"""Agent API v2 — programmatic form lifecycle for AI agents and integrations.

Authenticated via API key in the Authorization header:
    Authorization: Bearer afk_live_...

All routes return JSON. Errors use standard HTTP status codes.
"""
from functools import wraps

import json
import logging
import os
import re

logger = logging.getLogger(__name__)

from flask import Blueprint, request, jsonify, g

# App-wide base URL (from env, fallback to production default)
APP_URL = os.environ.get("APP_URL", "https://agentforms.io")

from app.models import (
    get_db,
    get_user,
    generate_api_key,
    validate_api_key,
    list_api_keys,
    revoke_api_key,
    check_api_permission,
    find_site_by_token,
    add_site,
    get_user_sites,
    delete_site,
    parse_site_fields,
    update_site_fields,
    get_submission,
    _decrypt_submission_fields,
    _get_site_owner_password_hash,
    TIERS,
    get_site_analytics,
    get_site_analytics_summary,
    site_geo_stats,
    site_device_stats,
    site_impression_stats,
    get_user_tier,
    get_site_versions,
    get_site_version,
    rollback_site_version,
    get_version_limit,
    create_campaign,
    get_campaign,
    list_campaigns,
    add_campaign_recipients,
    update_campaign_status,
    delete_campaign,
    get_campaign_recipients,
    get_email_settings,
    upsert_email_settings,
    get_custom_templates,
    get_custom_template,
    create_custom_template,
    update_custom_template,
    delete_custom_template,
    # Phase 4
    create_reminder,
    get_reminders,
    cancel_reminder,
    schedule_reminders_for_campaign,
    check_send_quota,
    record_send,
    create_ab_test,
    get_ab_test_info,
    assign_recipients_to_variants,
    send_ab_winner_to_remaining,
)
from app.services.form_logic import build_config_response
from app.services.campaign_emails import enqueue_campaign


def _get_user_password_hash(user_id):
    """Look up the password hash for a user (for submission decryption)."""
    conn = None
    try:
        conn = get_db()
        row = conn.execute(
            "SELECT password_hash FROM users WHERE id = ?", (user_id,)
        ).fetchone()
    finally:
        if conn:
            conn.close()
    if row:
        return dict(row)["password_hash"]
    return None


agent_api_bp = Blueprint("agent_api", __name__, url_prefix="/api/v2")


# ─── Auth middleware ────────────────────────────────────────────────────────


def api_key_required(f):
    """Require a valid API key in the Authorization header.

    Sets g.api_user_id and g.api_permissions on success.
    """
    @wraps(f)
    def decorated(*args, **kwargs):
        auth_header = request.headers.get("Authorization", "")
        if not auth_header.startswith("Bearer "):
            return jsonify({"error": "Missing or malformed Authorization header. Use 'Bearer afk_live_...'"}), 401

        raw_key = auth_header[7:]  # strip 'Bearer '
        user_id, permissions = validate_api_key(raw_key)

        if user_id is None:
            return jsonify({"error": "Invalid API key"}), 401

        g.api_user_id = user_id
        g.api_permissions = permissions
        return f(*args, **kwargs)

    return decorated


def require_permission(action):
    """Check that the authenticated API key has the required permission.

    Must be used after @api_key_required.
    """
    def decorator(f):
        @wraps(f)
        def decorated(*args, **kwargs):
            if not check_api_permission(g.api_permissions, action):
                return jsonify({"error": f"Permission denied: '{action}' required"}), 403
            return f(*args, **kwargs)
        return decorated
    return decorator


# ─── API Key verification (public — key IS the auth) ───────────────────────


@agent_api_bp.route("/verify", methods=["GET"])
def verify_key():
    """Verify an API key and return the associated tier.

    Lightweight endpoint for relay/integrations to check subscription status.
    No Bearer header needed — key is passed as query param.

    Returns:
        {"tier": "free"} or {"tier": "starter"}, etc.
        401 if key is invalid.
    """
    from app.models import get_user_tier

    raw_key = request.args.get("key", "")
    if not raw_key:
        return jsonify({"error": "Missing 'key' query parameter"}), 400

    user_id, _ = validate_api_key(raw_key)
    if user_id is None:
        return jsonify({"error": "Invalid API key"}), 401

    tier_key, _ = get_user_tier(user_id)
    return jsonify({"tier": tier_key, "key_prefix": raw_key[:12]})


# ─── API Key management ────────────────────────────────────────────────────


@agent_api_bp.route("/keys", methods=["GET"])
@api_key_required
def list_keys():
    """List all API keys for the authenticated user."""
    keys = list_api_keys(g.api_user_id)
    return jsonify({"keys": keys})


@agent_api_bp.route("/keys", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def create_key():
    """Create a new API key.

    Request body:
        name: Human-readable name (required)
        permissions: Optional permissions dict
    """
    data = request.get_json(silent=True) or {}
    name = data.get("name", "").strip()

    if not name:
        return jsonify({"error": "Key name is required"}), 400

    # Validate permissions
    permissions = data.get("permissions", None)
    if permissions:
        valid_perms = {"read_forms", "write_forms", "read_submissions", "delete_forms"}
        for key in permissions:
            if key not in valid_perms:
                return jsonify({"error": f"Invalid permission: '{key}'. Valid: {list(valid_perms)}"}), 400

    try:
        result = generate_api_key(name, g.api_user_id, permissions)
    except ValueError as e:
        return jsonify({"error": str(e)}), 409
    return jsonify({
        "id": result["id"],
        "key_prefix": result["key_prefix"],
        "full_key": result["full_key"],
        "name": result["name"],
        "permissions": result["permissions"],
        "created_at": None,
        "warning": "Store the full_key securely. It will not be shown again."
    }), 201


@agent_api_bp.route("/keys/<int:key_id>", methods=["DELETE"])
@api_key_required
@require_permission("delete_forms")
def revoke_key(key_id):
    """Revoke an API key."""
    success = revoke_api_key(key_id, g.api_user_id)
    if not success:
        return jsonify({"error": "API key not found or already revoked"}), 404

    return jsonify({"revoked": True, "id": key_id})


# ─── Form CRUD ──────────────────────────────────────────────────────────────


@agent_api_bp.route("/forms", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def list_forms():
    """List all forms for the authenticated user.

    Query params:
        limit: Max results (default 50, max 200)
        offset: Page offset (default 0)
    """
    limit = min(request.args.get("limit", 50, type=int), 200)
    offset = max(request.args.get("offset", 0, type=int), 0)

    sites = get_user_sites(g.api_user_id)

    # Build response
    forms = []
    for site in sites:
        field_config = parse_site_fields(site)
        forms.append({
            "id": site["id"],
            "token": site["token"],
            "name": site["name"],
            "field_count": len(field_config) if field_config else 0,
            "created_by": site.get("created_by", "manual"),
            "created_at": site["created_at"],
        })

    total = len(forms)
    paginated = forms[offset:offset + limit]

    return jsonify({
        "forms": paginated,
        "total": total,
        "limit": limit,
        "offset": offset,
    })


@agent_api_bp.route("/forms", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def create_form():
    """Create a new form.

    Request body:
        name: Form name (required)
        fields: Array of field definitions
        metadata: Optional JSON metadata

    Field definition:
        {
            "name": "field_name",
            "label": "Display Label",
            "type": "text" | "email" | "tel" | "textarea" | "select",
            "required": true,
            "options": [...]  // for select type
        }
    """
    data = request.get_json(silent=True) or {}
    name = data.get("name", "").strip()

    if not name:
        return jsonify({"error": "Form name is required"}), 400

    fields = data.get("fields", [])
    if not isinstance(fields, list):
        return jsonify({"error": "'fields' must be an array"}), 400

    if len(fields) == 0:
        return jsonify({"error": "At least one field is required"}), 422

    # Validate field definitions
    valid_types = {"text", "email", "tel", "textarea", "select", "number", "date", "hidden"}
    for i, field in enumerate(fields):
        if not isinstance(field, dict):
            return jsonify({"error": f"Field {i} must be an object"}), 400
        if "name" not in field or "label" not in field or "type" not in field:
            return jsonify({"error": f"Field {i} must have 'name', 'label', and 'type'"}), 400
        if field["type"] not in valid_types:
            return jsonify({"error": f"Field {i}: invalid type '{field['type']}'. Valid: {list(valid_types)}"}), 400

    # Check tier site limit
    user = get_user(g.api_user_id)
    from app.models import get_user_site_count
    current_count = get_user_site_count(g.api_user_id)
    tier_config = TIERS.get(user["tier"], TIERS["free"])
    max_sites = tier_config["max_sites"]

    if max_sites > 0 and current_count >= max_sites:
        return jsonify({
            "error": "Site limit reached for your tier",
            "current": current_count,
            "max": max_sites,
        }), 403

    metadata = data.get("metadata", None)

    site = add_site(
        name=name,
        owner_email=user["email"],
        user_id=g.api_user_id,
        field_config=fields,
    )

    # Update created_by and metadata
    conn = None
    try:
        conn = get_db()
        updates = []
        params = []
        updates.append("created_by = ?")
        params.append("agent")
        if metadata:
            updates.append("metadata = ?")
            params.append(json.dumps(metadata) if isinstance(metadata, dict) else str(metadata))
        params.append(site["id"])
        conn.execute(f"UPDATE sites SET {', '.join(updates)} WHERE id = ?", params)
        conn.commit()
    
        # Refresh site data
        site = conn.execute("SELECT * FROM sites WHERE id = ?", (site["id"],)).fetchone()
    finally:
        if conn:
            conn.close()
    site = dict(site)

    return jsonify({
        "id": site["id"],
        "token": site["token"],
        "name": site["name"],
        "fields": fields,
        "created_by": "agent",
    "embed_url": f"{APP_URL}/embed.js",
        "submit_url": f"{APP_URL}/api/submit?token={site['token']}",
        "created_at": site["created_at"],
    }), 201


@agent_api_bp.route("/forms/<form_token>", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def get_form(form_token):
    """Get form details by token.

    Returns full form definition including fields and settings.
    """
    site = find_site_by_token(form_token)
    if not site or site.get("user_id") != g.api_user_id:
        return jsonify({"error": "Form not found"}), 404

    field_config = parse_site_fields(site)

    return jsonify({
        "id": site["id"],
        "token": site["token"],
        "name": site["name"],
        "fields": field_config,
        "field_count": len(field_config) if field_config else 0,
        "created_by": site.get("created_by", "manual"),
        "metadata": json.loads(site["metadata"]) if site.get("metadata") else None,
        "honeypot_enabled": bool(site.get("honeypot_enabled", 1)),
        "spam_filter_enabled": bool(site.get("spam_filter_enabled", 1)),
        "webhook_enabled": bool(site.get("webhook_enabled", 0)),
        "rate_limit_enabled": bool(site.get("rate_limit_enabled", 1)),
    "embed_url": f"{APP_URL}/embed.js",
        "submit_url": f"{APP_URL}/api/submit?token={site['token']}",
        "created_at": site["created_at"],
    })


@agent_api_bp.route("/forms/<form_token>", methods=["DELETE"])
@api_key_required
@require_permission("delete_forms")
def delete_form(form_token):
    """Delete a form and all its submissions."""
    site = find_site_by_token(form_token)
    if not site or site.get("user_id") != g.api_user_id:
        return jsonify({"error": "Form not found"}), 404

    delete_site(site["id"])

    return jsonify({"deleted": True, "id": site["id"], "token": form_token})


@agent_api_bp.route("/forms/<form_token>/fields", methods=["PUT"])
@api_key_required
@require_permission("write_forms")
def update_fields(form_token):
    """Update form fields.

    Request body:
        fields: Array of field definitions (replaces existing)
    """
    site = find_site_by_token(form_token)
    if not site or site.get("user_id") != g.api_user_id:
        return jsonify({"error": "Form not found"}), 404

    data = request.get_json(silent=True) or {}
    fields = data.get("fields")

    if fields is None:
        return jsonify({"error": "'fields' is required"}), 400

    if not isinstance(fields, list):
        return jsonify({"error": "'fields' must be an array"}), 400

    # Validate
    valid_types = {"text", "email", "tel", "textarea", "select", "number", "date", "hidden"}
    for i, field in enumerate(fields):
        if not isinstance(field, dict):
            return jsonify({"error": f"Field {i} must be an object"}), 400
        if "name" not in field or "label" not in field or "type" not in field:
            return jsonify({"error": f"Field {i} must have 'name', 'label', and 'type'"}), 400
        if field["type"] not in valid_types:
            return jsonify({"error": f"Field {i}: invalid type '{field['type']}'"}), 400

    updated = update_site_fields(site["id"], field_config=fields, changed_by="api_key", change_reason="Fields updated via agent API")

    return jsonify({
        "updated": True,
        "fields": fields,
        "field_count": len(fields),
    })


# ─── Form config (public — no auth needed) ─────────────────────────────────


@agent_api_bp.route("/forms/<form_token>/config", methods=["GET"])
def get_form_config(form_token):
    """Get public form configuration.

    Used by embed SDK and WordPress plugin to render forms.
    No authentication required — only returns renderable data.
    """
    site = find_site_by_token(form_token)
    if not site:
        return jsonify({"error": "Form not found"}), 404

    field_config = parse_site_fields(site)

    config = build_config_response(site, field_config)
    config["submit_endpoint"] = f"/api/submit?token={site['token']}"

    return jsonify(config)


# ─── Version history (authenticated) ──────────────────────────────────────


@agent_api_bp.route("/forms/<form_token>/versions", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def list_versions(form_token):
    """GET /api/v2/forms/{token}/versions — list version history for a form."""
    site = find_site_by_token(form_token)
    if not site:
        return jsonify({"error": "Form not found"}), 404

    if not check_api_permission(g.api_permissions, "read_forms"):
        return jsonify({"error": "Access denied"}), 403

    user_id = site.get("user_id")
    if user_id:
        tier_key, _ = get_user_tier(user_id)
        limit = get_version_limit(tier_key)
    else:
        limit = None

    versions = get_site_versions(site["id"], limit=limit)
    return jsonify({
        "site_id": site["id"],
        "token": form_token,
        "versions": versions,
        "count": len(versions),
    })


@agent_api_bp.route("/forms/<form_token>/versions/<int:version_id>", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def get_version(form_token, version_id):
    """GET /api/v2/forms/{token}/versions/{version} — get specific version."""
    site = find_site_by_token(form_token)
    if not site:
        return jsonify({"error": "Form not found"}), 404

    version = get_site_version(site["id"], version_id)
    if not version:
        return jsonify({"error": "Version not found"}), 404

    return jsonify({
        "site_id": site["id"],
        "version": version,
    })


@agent_api_bp.route("/forms/<form_token>/versions/<int:version_id>/rollback", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def rollback_version(form_token, version_id):
    """POST /api/v2/forms/{token}/versions/{version}/rollback — revert to version."""
    site = find_site_by_token(form_token)
    if not site:
        return jsonify({"error": "Form not found"}), 404

    data = request.get_json(silent=True) or {}
    change_reason = data.get("reason", None)

    target = get_site_version(site["id"], version_id)
    if not target:
        return jsonify({"error": "Version not found"}), 404

    new_ver = rollback_site_version(
        site["id"], version_id,
        changed_by=f"api_user:{g.api_user_id}",
        change_reason=change_reason
    )

    if new_ver is None:
        return jsonify({"error": "Rollback failed"}), 500

    return jsonify({
        "rolled_back": True,
        "new_version": new_ver,
        "restored_from": version_id,
    })


# ─── Submissions ────────────────────────────────────────────────────────────


@agent_api_bp.route("/forms/<form_token>/submissions", methods=["GET"])
@api_key_required
@require_permission("read_submissions")
def list_form_submissions(form_token):
    """List submissions for a form.

    Query params:
        limit: Max results (default 50, max 200)
        offset: Page offset (default 0)
    """
    site = find_site_by_token(form_token)
    if not site or site.get("user_id") != g.api_user_id:
        return jsonify({"error": "Form not found"}), 404

    limit = min(request.args.get("limit", 50, type=int), 200)
    offset = max(request.args.get("offset", 0, type=int), 0)

    conn = None
    try:
        conn = get_db()
        total_row = conn.execute(
            "SELECT COUNT(*) as cnt FROM submissions WHERE site_id = ?",
            (site["id"],),
        ).fetchone()
        total = total_row["cnt"]
    
        rows = conn.execute(
            """SELECT * FROM submissions WHERE site_id = ?
                ORDER BY submitted_at DESC LIMIT ? OFFSET ?""",
            (site["id"], limit, offset),
        ).fetchall()
    finally:
        if conn:
            conn.close()

    # Decrypt submissions using owner's password hash
    pw_hash = _get_site_owner_password_hash(site["id"])

    submissions = []
    for row in rows:
        d = dict(row)
        # Decrypt PII + dynamic data (user-scoped encryption)
        d = _decrypt_submission_fields(site["id"], d, pw_hash)
        # Parse dynamic field data
        if d.get("data"):
            try:
                d["dynamic_data"] = json.loads(d["data"])
            except (json.JSONDecodeError, TypeError):
                d["dynamic_data"] = {}
        else:
            d["dynamic_data"] = {}

        submissions.append(d)

    return jsonify({
        "submissions": submissions,
        "total": total,
        "limit": limit,
        "offset": offset,
    })


@agent_api_bp.route("/forms/<form_token>/submissions/<int:sub_id>", methods=["GET"])
@api_key_required
@require_permission("read_submissions")
def get_form_submission(form_token, sub_id):
    """Get a single submission by ID."""
    site = find_site_by_token(form_token)
    if not site or site.get("user_id") != g.api_user_id:
        return jsonify({"error": "Form not found"}), 404

    submission = get_submission(sub_id, password_hash=_get_user_password_hash(g.api_user_id))
    if not submission or submission["site_id"] != site["id"]:
        return jsonify({"error": "Submission not found"}), 404

    # Parse dynamic data
    if submission.get("data"):
        try:
            submission["dynamic_data"] = json.loads(submission["data"])
        except (json.JSONDecodeError, TypeError):
            submission["dynamic_data"] = {}
    else:
        submission["dynamic_data"] = {}

    return jsonify(submission)


# ── Analytics ──────────────────────────────────────────────────────────────


@agent_api_bp.route("/forms/<form_token>/analytics", methods=["GET"])
@api_key_required
@require_permission("read_submissions")
def form_analytics(form_token):
    """Get analytics for a form.

    Tier-gated: Free gets basic only, Starter gets +geo/device, Pro+ gets everything.

    Query params:
        days: Days to include (default 30, max 90)
    """
    site = find_site_by_token(form_token)
    if not site or site.get("user_id") != g.api_user_id:
        return jsonify({"error": "Form not found"}), 404

    days = min(request.args.get("days", 30, type=int), 90)

    # Resolve user tier and analytics level
    tier_key, tier_config = get_user_tier(g.api_user_id)
    analytics_level = tier_config["analytics"]

    # Basic analytics (always available)
    daily_data = get_site_analytics(site["id"], days)
    summary = get_site_analytics_summary(site["id"])

    result = {
        "form_id": site["id"],
        "form_token": site["token"],
        "tier": tier_key,
        "analytics_level": analytics_level,
        "days": days,
        "daily_submissions": [dict(d) for d in daily_data],
        "summary": summary,
    }

    # Geo stats (Starter+)
    if analytics_level in ["standard", "advanced"]:
        result["geo"] = site_geo_stats(site["id"])

    # Device stats (Starter+)
    if analytics_level in ["standard", "advanced"]:
        result["device"] = site_device_stats(site["id"])

    # Impressions & conversion (Pro+)
    if analytics_level == "advanced":
        result["impressions"] = site_impression_stats(site["id"], days)

    return jsonify(result)


# ─── Email Campaigns ────────────────────────────────────────────────────────


@agent_api_bp.route("/campaigns", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def list_campaigns_route():
    """List campaigns for the authenticated user.

    Query params:
        status: Filter by status (draft, scheduled, sending, sent, failed, cancelled)
        limit: Max results (default 50, max 200)
        offset: Page offset (default 0)
    """
    status = request.args.get("status")
    limit = min(request.args.get("limit", 50, type=int), 200)
    offset = max(request.args.get("offset", 0, type=int), 0)

    campaigns = list_campaigns(g.api_user_id, status=status, limit=limit, offset=offset)

    return jsonify({
        "campaigns": campaigns,
        "total": len(campaigns),
        "limit": limit,
        "offset": offset,
    })


@agent_api_bp.route("/campaigns", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def create_campaign_route():
    """Create a new email campaign.

    Request body:
        name: Campaign name (required)
        subject: Email subject line (required)
        body: Email body (HTML) (required)
        from_name: Sender name (optional)
        from_email: Sender email (optional)
        template_id: Template ID (optional)
        scheduled_at: ISO 8601 timestamp (optional)
        recipients: Array of email addresses (optional)
    """
    data = request.get_json(silent=True) or {}
    name = data.get("name", "").strip()
    subject = data.get("subject", "").strip()
    body = data.get("body", "").strip()

    if not name:
        return jsonify({"error": "Campaign name is required"}), 400
    if not subject:
        return jsonify({"error": "Email subject is required"}), 400
    if not body:
        return jsonify({"error": "Email body is required"}), 400

    # Check tier email limit
    user = get_user(g.api_user_id)
    tier_config = TIERS.get(user["tier"], TIERS["free"])
    max_campaigns = tier_config.get("max_campaigns", 0)
    max_recipients = tier_config.get("max_recipients_per_campaign", 0)

    if max_campaigns > 0:
        existing = list_campaigns(g.api_user_id)
        if len(existing) >= max_campaigns:
            return jsonify({
                "error": "Campaign limit reached for your tier",
                "current": len(existing),
                "max": max_campaigns,
            }), 403

    recipients = data.get("recipients", [])
    if max_recipients > 0 and len(recipients) > max_recipients:
        return jsonify({
            "error": f"Recipient limit exceeded. Max {max_recipients} per campaign.",
            "count": len(recipients),
            "max": max_recipients,
        }), 403

    campaign = create_campaign(
        user_id=g.api_user_id,
        name=name,
        subject=subject,
        body=body,
        from_name=data.get("from_name"),
        from_email=data.get("from_email"),
        template_id=data.get("template_id"),
        scheduled_at=data.get("scheduled_at"),
    )

    # Add recipients
    if recipients:
        add_campaign_recipients(campaign["id"], g.api_user_id, recipients)

    return jsonify(campaign), 201


@agent_api_bp.route("/campaigns/<int:campaign_id>", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def get_campaign_route(campaign_id):
    """Get campaign details including stats."""
    campaign = get_campaign(campaign_id, g.api_user_id)
    if not campaign:
        return jsonify({"error": "Campaign not found"}), 404

    return jsonify(campaign)


@agent_api_bp.route("/campaigns/<int:campaign_id>", methods=["DELETE"])
@api_key_required
@require_permission("delete_forms")
def delete_campaign_route(campaign_id):
    """Delete a campaign and its recipients."""
    success = delete_campaign(campaign_id, g.api_user_id)
    if not success:
        return jsonify({"error": "Campaign not found"}), 404

    return jsonify({"deleted": True, "id": campaign_id})


@agent_api_bp.route("/campaigns/<int:campaign_id>/recipients", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def list_recipients_route(campaign_id):
    """List recipients for a campaign.

    Query params:
        status: Filter by status (pending, sent, failed, bounced)
        limit: Max results (default 100, max 500)
        offset: Page offset (default 0)
    """
    status = request.args.get("status")
    limit = min(request.args.get("limit", 100, type=int), 500)
    offset = max(request.args.get("offset", 0, type=int), 0)

    recipients = get_campaign_recipients(campaign_id, g.api_user_id, status=status, limit=limit, offset=offset)

    return jsonify({
        "recipients": recipients,
        "total": len(recipients),
        "limit": limit,
        "offset": offset,
    })


@agent_api_bp.route("/campaigns/<int:campaign_id>/recipients", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def add_recipients_route(campaign_id):
    """Add recipients to a campaign.

    Request body:
        recipients: Array of email addresses (required)
    """
    data = request.get_json(silent=True) or {}
    recipients = data.get("recipients", [])

    if not recipients or not isinstance(recipients, list):
        return jsonify({"error": "recipients must be a non-empty array"}), 400

    # Check tier recipient limit
    user = get_user(g.api_user_id)
    tier_config = TIERS.get(user["tier"], TIERS["free"])
    max_recipients = tier_config.get("max_recipients_per_campaign", 0)

    if max_recipients > 0:
        existing = get_campaign_recipients(campaign_id, g.api_user_id, limit=99999)
        if len(existing) + len(recipients) > max_recipients:
            return jsonify({
                "error": f"Recipient limit exceeded. Max {max_recipients} per campaign.",
                "current": len(existing),
                "adding": len(recipients),
                "max": max_recipients,
            }), 403

    result = add_campaign_recipients(campaign_id, g.api_user_id, recipients)
    if "error" in result:
        return jsonify(result), 404

    return jsonify(result)


@agent_api_bp.route("/campaigns/<int:campaign_id>/send", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def send_campaign_route(campaign_id):
    """Send a campaign immediately.

    Updates status to 'sending' and queues emails for delivery.
    """
    campaign = get_campaign(campaign_id, g.api_user_id)
    if not campaign:
        return jsonify({"error": "Campaign not found"}), 404

    if campaign["status"] not in ("draft", "scheduled"):
        return jsonify({"error": f"Cannot send campaign with status '{campaign['status']}'"}), 400

    # Update status
    update_campaign_status(campaign_id, g.api_user_id, "sending")

    # Queue for delivery
    enqueue_campaign(campaign_id)

    return jsonify({
        "queued": True,
        "campaign_id": campaign_id,
        "status": "sending",
    })


@agent_api_bp.route("/campaigns/<int:campaign_id>/cancel", methods=["POST"])
@api_key_required
@require_permission("write_forms")
def cancel_campaign_route(campaign_id):
    """Cancel a scheduled or sending campaign."""
    campaign = get_campaign(campaign_id, g.api_user_id)
    if not campaign:
        return jsonify({"error": "Campaign not found"}), 404

    if campaign["status"] not in ("scheduled", "sending"):
        return jsonify({"error": f"Cannot cancel campaign with status '{campaign['status']}'"}), 400

    update_campaign_status(campaign_id, g.api_user_id, "cancelled")

    return jsonify({
        "cancelled": True,
        "campaign_id": campaign_id,
        "status": "cancelled",
    })


@agent_api_bp.route("/campaigns/<int:campaign_id>/analytics")
@api_key_required
@require_permission("read_forms")
def campaign_analytics_route(campaign_id):
    """Get open/click/bounce analytics for a campaign."""
    from app.models import get_campaign_analytics

    campaign = get_campaign(campaign_id, g.api_user_id)
    if not campaign:
        return jsonify({"error": "Campaign not found"}), 404

    analytics = get_campaign_analytics(campaign_id, g.api_user_id)
    if analytics is None:
        return jsonify({"error": "No analytics data"}), 404

    return jsonify({"campaign_id": campaign_id, "analytics": analytics})


# ─── Email Settings ─────────────────────────────────────────────────────────


# ─── Direct email send (agent-facing) ──────────────────────────────────────────


@agent_api_bp.route("/email/send", methods=["POST"])
@api_key_required
def send_email_v2():
    """POST /api/v2/email/send — Send an email via the user's configured SMTP.

    Available to paid tiers only. Free tier gets 403.

    Request body:
        to: Recipient email address (required)
        subject: Email subject (required)
        body: Plain-text or HTML body (required)
        html: Optional HTML body (if provided, sent as HTML email)
        from_addr: Optional override for SMTP_FROM

    Response:
        {\"success\": true, \"to\": \"...\", \"id\": \"...\"}
    """
    from app.models import get_user, get_user_tier
    from app.routes.email import NotificationService

    user_id = g.api_user_id

    # Tier gate: free tier cannot use direct email send
    user = get_user(user_id)
    if not user:
        return jsonify({"error": "User not found"}), 404

    tier_key, _ = get_user_tier(user_id)
    tier_config = TIERS.get(tier_key, TIERS["free"])
    max_sends = tier_config.get("max_api_email_sends", 0)

    if max_sends <= 0:
        return jsonify({
            "error": "Direct email send requires a paid plan",
            "tier": tier_key,
            "upgrade_url": "/billing",
        }), 403

    # Check rate limit
    quota = check_send_quota(user_id)
    if not quota.get("can_send", False):
        return jsonify({
            "error": "Send quota exceeded",
            "quota": quota,
        }), 429

    data = request.get_json(silent=True) or {}

    to = data.get("to", "").strip()
    subject = data.get("subject", "").strip()
    body = data.get("body", "").strip()
    html = data.get("html", None)
    from_addr = data.get("from_addr", None)

    if not to or not subject:
        return jsonify({"error": "Missing required fields: to, subject"}), 400

    if not body and not html:
        return jsonify({"error": "At least one of 'body' or 'html' is required"}), 400

    # Send the email
    if html:
        success = NotificationService.send_html(to, subject, html, body or None, from_addr)
    else:
        success = NotificationService.send(to, subject, body, from_addr)

    if success:
        # Record the send for rate limiting
        record_send(user_id, count=1)
        return jsonify({"success": True, "to": to})
    else:
        return jsonify({"error": "Failed to send email. Check SMTP configuration."}), 502


# ─── Email settings ──────────────────────────────────────────────────────────


@agent_api_bp.route("/email/settings", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def get_email_settings_route():
    """Get email sender settings."""
    settings = get_email_settings(g.api_user_id)
    return jsonify({"settings": settings})


@agent_api_bp.route("/email/settings", methods=["PUT"])
@api_key_required
@require_permission("write_templates")
def update_email_settings_route():
    """Update email sender settings.

    Request body:
        from_name: Sender display name
        from_email: Sender email address
        reply_to: Reply-to email address
        template_id: Default template ID
        sender_domain: Custom sender domain (e.g., mail.example.com)
        default_template: Default template name
    """
    data = request.get_json(silent=True) or {}

    # Validate sender domain if provided
    sender_domain = data.get("sender_domain")
    if sender_domain is not None:
        sender_domain = sender_domain.strip().lower()
        if sender_domain and not re.match(r"^[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$", sender_domain):
            return jsonify({
                "error": "Invalid domain format"
            }), 400

    settings = upsert_email_settings(
        user_id=g.api_user_id,
        from_name=data.get("from_name"),
        from_email=data.get("from_email"),
        reply_to=data.get("reply_to"),
        template_id=data.get("template_id"),
        sender_domain=sender_domain,
        domain_verified=data.get("domain_verified"),
        default_template=data.get("default_template"),
    )

    return jsonify({"settings": settings})


# ─── Sender Domain Verification ───────────────────────────────────────────


@agent_api_bp.route("/email/domain/verify", methods=["POST"])
@api_key_required
@require_permission("write_templates")
def verify_sender_domain_route():
    """Initiate sender domain verification.

    Returns DNS records the user needs to add to verify ownership.

    Request body:
        domain: Domain to verify (required)
    """
    data = request.get_json(silent=True) or {}

    domain = data.get("domain", "").strip().lower()
    if not domain:
        return jsonify({"error": "Domain is required"}), 400

    if not re.match(r"^[a-zA-Z0-9.-]+\.?[a-zA-Z]{2,}$", domain):
        return jsonify({"error": "Invalid domain format"}), 400

    # Generate verification token
    import secrets
    verification_token = secrets.token_hex(32)

    # Store verification token (in practice, store in DB with expiry)
    # For now, return the DNS records the user needs to add
    dns_records = {
        "txt": {
            "name": f"_agentforms-verify.{domain}",
            "value": f"agentforms-verification={verification_token}",
            "ttl": 3600,
        },
        "dkim": {
            "name": f"agentforms._domainkey.{domain}",
            "value": f"v=DKIM1; k=rsa; p={generate_dkim_public_key_placeholder()}",
            "ttl": 3600,
        },
        "spf": {
            "name": domain,
            "value": f"include:agentforms.io",
            "type": "add_to_existing",
            "ttl": 3600,
        },
        "dmarc": {
            "name": f"_dmarc.{domain}",
            "value": "v=DMARC1; p=none; rua=mailto:dmarc@agentforms.io",
            "ttl": 3600,
        },
    }

    # Update email settings with domain and verification token
    existing = get_email_settings(g.api_user_id)
    upsert_email_settings(
        user_id=g.api_user_id,
        from_name=(existing or {}).get("from_name"),
        from_email=(existing or {}).get("from_email"),
        reply_to=(existing or {}).get("reply_to"),
        template_id=(existing or {}).get("template_id"),
        sender_domain=domain,
        domain_verified=False,
        default_template=(existing or {}).get("default_template"),
    )

    return jsonify({
        "domain": domain,
        "status": "pending",
        "verification_token": verification_token,
        "dns_records": dns_records,
        "instructions": {
            "title": "Verify Your Domain",
            "steps": [
                "Add the TXT record to your DNS to prove ownership",
                "Add the DKIM record for email signing",
                "Update your SPF record to include AgentForms",
                "Add the DMARC record for policy enforcement",
                "Click 'Verify' again once DNS propagation is complete",
            ],
            "note": "DNS propagation can take up to 48 hours",
        },
    })


@agent_api_bp.route("/email/domain/check", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def check_sender_domain_route():
    """Check the verification status of the configured sender domain."""
    settings = get_email_settings(g.api_user_id)

    if not settings:
        return jsonify({
            "domain": None,
            "status": "not_configured",
        })

    domain = settings.get("sender_domain")
    if not domain:
        return jsonify({
            "domain": None,
            "status": "not_configured",
        })

    return jsonify({
        "domain": domain,
        "status": "verified" if settings.get("domain_verified") else "pending",
        "verified_at": settings.get("domain_verified_at") if settings.get("domain_verified") else None,
    })


def generate_dkim_public_key_placeholder():
    """Generate a placeholder DKIM public key for display.

    In production, this would generate a real key pair and store
    the private key securely.
    """
    # Placeholder — in production, generate actual RSA key pair
    return "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQC..."


# ─── Email Templates ──────────────────────────────────────────────────────


@agent_api_bp.route("/templates", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def list_templates_route():
    """List available email templates.

    Returns both built-in and user custom templates.
    """
    from app.emails.renderer import _get_renderer

    user_templates = get_custom_templates(g.api_user_id)
    renderer = _get_renderer()
    all_templates = renderer.list_templates()

    # Separate built-in from custom
    builtin = []
    custom = []

    for tpl in all_templates:
        entry = {
            "name": tpl["name"],
            "type": tpl["type"],
        }

        if tpl["type"] == "custom":
            # Check if this user owns it
            user_tpl = next((t for t in user_templates if t["name"] == tpl["name"]), None)
            if user_tpl:
                entry.update({
                    "description": user_tpl.get("description"),
                    "created_at": user_tpl.get("created_at"),
                    "updated_at": user_tpl.get("updated_at"),
                })
                custom.append(entry)
        else:
            builtin.append(entry)

    return jsonify({
        "builtin_templates": builtin,
        "custom_templates": custom,
    })


@agent_api_bp.route("/templates", methods=["POST"])
@api_key_required
@require_permission("write_templates")
def create_template_route():
    """Create a custom email template.

    Request body:
        name: Template name (required, unique per user)
        content: HTML template content (required)
        description: Template description (optional)
    """
    data = request.get_json(silent=True) or {}

    name = data.get("name", "").strip()
    content = data.get("content", "").strip()

    if not name:
        return jsonify({"error": "Template name is required"}), 400
    if not content:
        return jsonify({"error": "Template content is required"}), 400

    # Validate name format
    import re
    if not re.match(r"^[a-zA-Z][a-zA-Z0-9_-]*$", name):
        return jsonify({
            "error": "Template name must start with a letter and contain only letters, numbers, hyphens, and underscores"
        }), 400

    # Check tier limit (max_templates=0 means no custom templates allowed)
    user = get_user(g.api_user_id)
    tier_config = TIERS.get(user["tier"], TIERS["free"])
    max_templates = tier_config.get("max_custom_templates", 0)

    if max_templates >= 0:
        existing = get_custom_templates(g.api_user_id)
        if len(existing) >= max_templates:
            return jsonify({
                "error": "Custom template limit reached for your tier",
                "current": len(existing),
                "max": max_templates,
            }), 403

    # Validate template syntax by attempting to render
    from app.emails.renderer import _get_renderer
    renderer = _get_renderer()

    # Test render with empty context to catch syntax errors
    try:
        renderer.env.from_string(content)
    except Exception as e:
        return jsonify({"error": f"Invalid template syntax: {str(e)}"}), 400

    template = create_custom_template(
        user_id=g.api_user_id,
        name=name,
        content=content,
        description=data.get("description"),
    )

    # Also save to disk for the renderer
    renderer.save_custom_template(name, content)

    return jsonify({"template": template}), 201


@agent_api_bp.route("/templates/<name>", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def get_template_route(name):
    """Get a custom template by name.

    Returns template details and content preview.
    """
    template = get_custom_template(g.api_user_id, name)

    if not template:
        return jsonify({"error": "Template not found"}), 404

    # Don't return full content on GET — use separate endpoint
    result = {
        "name": template["name"],
        "description": template.get("description"),
        "created_at": template.get("created_at"),
        "updated_at": template.get("updated_at"),
    }

    return jsonify({"template": result})


@agent_api_bp.route("/templates/<name>/content", methods=["GET"])
@api_key_required
@require_permission("read_forms")
def get_template_content_route(name):
    """Get the raw content of a custom or built-in template."""
    from app.emails.renderer import _get_renderer

    renderer = _get_renderer()

    # Check custom templates first
    template = get_custom_template(g.api_user_id, name)
    if template:
        return jsonify({
            "name": template["name"],
            "type": "custom",
            "content": template["content"],
            "description": template.get("description"),
        })

    # Fall back to built-in
    content = renderer.get_custom_template_content(name)
    if content:
        return jsonify({
            "name": name,
            "type": "builtin",
            "content": content,
        })

    return jsonify({"error": "Template not found"}), 404


@agent_api_bp.route("/templates/<name>", methods=["PUT"])
@api_key_required
@require_permission("write_templates")
def update_template_route(name):
    """Update a custom email template.

    Request body:
        content: HTML template content (optional)
        description: Template description (optional)
    """
    data = request.get_json(silent=True) or {}

    # Must have at least one field to update
    if "content" not in data and "description" not in data:
        return jsonify({"error": "No fields to update"}), 400

    existing = get_custom_template(g.api_user_id, name)
    if not existing:
        return jsonify({"error": "Template not found"}), 404

    content = data.get("content")
    if content is not None:
        # Validate syntax
        from app.emails.renderer import _get_renderer
        renderer = _get_renderer()
        try:
            renderer.env.from_string(content)
        except Exception as e:
            return jsonify({"error": f"Invalid template syntax: {str(e)}"}), 400

    template = update_custom_template(
        user_id=g.api_user_id,
        name=name,
        content=content,
        description=data.get("description"),
    )

    if not template:
        return jsonify({"error": "Template not found"}), 404

    # Update disk copy if content changed
    if content is not None:
        from app.emails.renderer import _get_renderer
        _get_renderer().save_custom_template(name, content)

    return jsonify({"template": template})


@agent_api_bp.route("/templates/<name>", methods=["DELETE"])
@api_key_required
@require_permission("write_templates")
def delete_template_route(name):
    """Delete a custom email template."""
    result = delete_custom_template(g.api_user_id, name)

    if not result:
        return jsonify({"error": "Template not found"}), 404

    return jsonify({"message": f"Template '{name}' deleted"})


@agent_api_bp.route("/templates/render", methods=["POST"])
@api_key_required
@require_permission("write_templates")
def render_template_route():
    """Render a template with the provided context (for preview/testing).

    Request body:
        template: Template name (required)
        context: Dict of template variables (optional)

    Returns rendered HTML.
    """
    from app.emails.renderer import _get_renderer

    data = request.get_json(silent=True) or {}

    template_name = data.get("template", "").strip()
    if not template_name:
        return jsonify({"error": "Template name is required"}), 400

    context = data.get("context", {})
    # Merge in defaults
    context.setdefault("base_url", os.environ.get("APP_URL", "https://agentforms.io"))

    renderer = _get_renderer()
    html = renderer.render(template_name, context)

    return jsonify({
        "template": template_name,
        "html": html,
    })


# --- Phase 4: Reminder Campaigns, A/B Testing, Rate Limiting ---


@agent_api_bp.route('/campaigns/<int:campaign_id>/reminders', methods=['GET'])
@api_key_required
@require_permission('read_forms')
def get_campaign_reminders_route(campaign_id):
    """Get all reminders for a campaign."""
    reminders = get_reminders(campaign_id, g.api_user_id)
    return jsonify({'reminders': reminders})


@agent_api_bp.route('/campaigns/<int:campaign_id>/reminders', methods=['POST'])
@api_key_required
@require_permission('write_templates')
def create_campaign_reminder_route(campaign_id):
    """Create a reminder for a campaign.

    Request body:
        delay_hours: Hours after campaign sent_at to send reminder
        subject: Email subject (supports {first_name}, {email})
        body: Email body HTML (supports {first_name}, {email})
        template_id: Optional template ID to render body from
    """
    data = request.get_json(silent=True) or {}

    delay_hours = data.get('delay_hours')
    subject = data.get('subject', '').strip()
    body = data.get('body', '').strip()
    template_id = data.get('template_id')

    if not delay_hours or not isinstance(delay_hours, (int, float)) or delay_hours <= 0:
        return jsonify({'error': 'delay_hours must be a positive number'}), 400
    if not subject:
        return jsonify({'error': 'subject is required'}), 400
    if not body:
        return jsonify({'error': 'body is required'}), 400

    reminder = create_reminder(campaign_id, g.api_user_id, delay_hours, subject, body, template_id)
    if not reminder:
        return jsonify({'error': 'Campaign not found or access denied'}), 404

    return jsonify({'reminder': reminder}), 201


@agent_api_bp.route('/campaigns/<int:campaign_id>/reminders/<int:reminder_id>', methods=['DELETE'])
@api_key_required
@require_permission('write_templates')
def cancel_campaign_reminder_route(campaign_id, reminder_id):
    """Cancel a scheduled reminder."""
    success = cancel_reminder(reminder_id, g.api_user_id)
    if not success:
        return jsonify({'error': 'Reminder not found or already sent'}), 404
    return jsonify({'success': True})


@agent_api_bp.route('/email/rate-limit', methods=['GET'])
@api_key_required
@require_permission('read_forms')
def get_rate_limit_route():
    """Get current rate limit quota for the user."""
    quota = check_send_quota(g.api_user_id)
    return jsonify(quota)


@agent_api_bp.route('/campaigns/<int:campaign_id>/ab-test', methods=['POST'])
@api_key_required
@require_permission('write_templates')
def create_ab_test_route(campaign_id):
    """Create an A/B test for a campaign.

    Request body:
        variants: List of {label, subject, body, split_percent}
        test_size: Percentage of recipients to include in test (default 20)
        metric: Metric to measure winner (opens, clicks, responses)
        declare_after_hours: Hours to wait before declaring winner (default 24)
    """
    data = request.get_json(silent=True) or {}

    variants = data.get('variants', [])
    if not variants or len(variants) < 2:
        return jsonify({'error': 'At least 2 variants are required'}), 400

    test_size = data.get('test_size', 20)
    metric = data.get('metric', 'opens')
    declare_after_hours = data.get('declare_after_hours', 24)

    if metric not in ('opens', 'clicks', 'responses'):
        return jsonify({'error': 'metric must be opens, clicks, or responses'}), 400

    result = create_ab_test(campaign_id, g.api_user_id, variants, test_size, metric, declare_after_hours)
    if not result:
        return jsonify({'error': 'Campaign not found or access denied'}), 404

    return jsonify({'variants': result}), 201


@agent_api_bp.route('/campaigns/<int:campaign_id>/ab-test', methods=['GET'])
@api_key_required
@require_permission('read_forms')
def get_ab_test_route(campaign_id):
    """Get A/B test info for a campaign."""
    info = get_ab_test_info(campaign_id, g.api_user_id)
    if not info:
        return jsonify({'error': 'Campaign not found or no A/B test configured'}), 404
    return jsonify(info)


@agent_api_bp.route('/campaigns/<int:campaign_id>/ab-test/assign', methods=['POST'])
@api_key_required
@require_permission('write_templates')
def assign_ab_variants_route(campaign_id):
    """Assign pending recipients to A/B test variants."""
    count = assign_recipients_to_variants(campaign_id, g.api_user_id)
    return jsonify({'assigned': count})
