"""
app.py — Qualora Enterprise Quality Auditor
===========================================
Core Flask app with modular architecture for MongoDB write-through,
Strict HTTP-Only JWT auth, RAG pipeline (Atlas Vector), and 
multi-tier LLM fallback cascade. Hardened for Vercel deployment.
"""
import os
# Ensure ChromaDB telemetry is disabled as early as possible so imported
# libraries (including chromadb) do not attempt PostHog capture calls.
os.environ.setdefault("CHROMADB_DISABLE_TELEMETRY", "1")
os.environ.setdefault("CHROMA_DISABLE_TELEMETRY", "1")
os.environ.setdefault("ANONYMIZED_TELEMETRY", "True")

import sys
import jwt
from datetime import datetime, timezone
from flask import Flask, request, jsonify, send_from_directory, render_template, redirect, url_for, make_response
from flask_cors import CORS
from services.security import generate_csrf_token, decode_token

# ── Import infrastructure ─────────────────────────────────────────────────────
from core import (
    BASE_DIR, ALLOWED_ORIGIN, MAX_CONTENT_LENGTH, DEBUG, GITHUB_URL, 
    JWT_SECRET, get_logger, log_request_middleware, get_db, get_db_status, LOG_LEVEL
)

# Import blueprints with graceful fallback if any fail
try:
    from routes.auth_bp import auth_bp
except Exception as e:
    auth_bp = None
    import traceback
    print(f"ERROR: Failed to import auth_bp: {e}\n{traceback.format_exc()}")

try:
    from routes.audits_bp import audits_bp
except Exception as e:
    audits_bp = None
    import traceback
    print(f"ERROR: Failed to import audits_bp: {e}\n{traceback.format_exc()}")

try:
    from routes.kb_bp import kb_bp
except Exception as e:
    kb_bp = None
    import traceback
    print(f"ERROR: Failed to import kb_bp: {e}\n{traceback.format_exc()}")

try:
    from routes.admin_bp import admin_bp
except Exception as e:
    admin_bp = None
    import traceback
    print(f"ERROR: Failed to import admin_bp: {e}\n{traceback.format_exc()}")

try:
    from routes.dashboard_bp import dashboard_bp
except Exception as e:
    dashboard_bp = None
    import traceback
    print(f"ERROR: Failed to import dashboard_bp: {e}\n{traceback.format_exc()}")

try:
    from routes.alerts_bp import alerts_bp
except Exception as e:
    alerts_bp = None
    import traceback
    print(f"ERROR: Failed to import alerts_bp: {e}\n{traceback.format_exc()}")

try:
    from routes.agents_bp import agents_bp
except Exception as e:
    agents_bp = None
    import traceback
    print(f"ERROR: Failed to import agents_bp: {e}\n{traceback.format_exc()}")

# ── Initialize logger ─────────────────────────────────────────────────────────
log = get_logger(__name__)

# ── Create Flask app ──────────────────────────────────────────────────────────
app = Flask(__name__, static_folder=None, template_folder=BASE_DIR)
app.config['MAX_CONTENT_LENGTH'] = MAX_CONTENT_LENGTH

# ── Enable CORS ───────────────────────────────────────────────────────────────
CORS(app, 
     resources={r"/*": {
         "origins": ALLOWED_ORIGIN,
         "methods": ["GET", "POST", "PUT", "DELETE", "OPTIONS", "PATCH"],
         "allow_headers": ["Content-Type", "X-CSRF-Token"], # Removed Authorization, using strict HTTP-Only cookies
         "expose_headers": ["X-CSRF-Token"],
         "supports_credentials": True,
         "max_age": 3600
     }})

# ── Security Headers Middleware ────────────────────────────────────────────────
@app.after_request
def set_security_headers(response):
    """Add enterprise-grade security headers to all responses."""
    response.headers['X-Frame-Options'] = 'DENY'
    response.headers['X-Content-Type-Options'] = 'nosniff'
    response.headers['X-XSS-Protection'] = '1; mode=block'
    response.headers['Referrer-Policy'] = 'strict-origin-when-cross-origin'
    
    # Content Security Policy: Strict definitions
    response.headers['Content-Security-Policy'] = (
        "default-src 'self'; "
        "script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net https://fonts.googleapis.com; "
        "style-src 'self' 'unsafe-inline' https://fonts.googleapis.com; " 
        "font-src 'self' https://fonts.gstatic.com; "
        "img-src 'self' data: https:; "
        "connect-src 'self' https:; "
        "object-src 'none'; "
        "frame-ancestors 'none'; "
        "upgrade-insecure-requests; "
        "base-uri 'self';"
    )
    
    # HSTS: enforce HTTPS (Always on in production, Vercel standard)
    if not DEBUG:
        response.headers['Strict-Transport-Security'] = 'max-age=31536000; includeSubDomains; preload'
    
    return response

# ── Global Jinja Context ─────────────────────────────────────────────────────
@app.context_processor
def inject_global_template_vars():
    # Attempt to decode JWT from HTTP-only cookie so templates can
    # perform server-side role-aware rendering (non-sensitive).
    user = None
    try:
        token = request.cookies.get('access_token')
        if token:
            payload = decode_token(token)
            if payload:
                # expose only non-sensitive fields to templates
                user = {
                    'email': payload.get('email'),
                    'role': payload.get('role'),
                    'org_id': payload.get('org_id')
                }
    except Exception:
        user = None

    return {
        'github_url': GITHUB_URL,
        'current_year': datetime.now(timezone.utc).year,
        'get_csrf_token': generate_csrf_token,
        'current_user': user,
        # Frontend may opt to disable console logging when server is set to OFF
        'quiet_logs': True if (isinstance(LOG_LEVEL, str) and LOG_LEVEL.upper() in ("OFF", "NONE", "DISABLED")) else False
    }

# ── Register middleware & blueprints ──────────────────────────────────────────
try:
    log_request_middleware(app)
except Exception as e:
    log.warning(f"Failed to register request middleware: {e}")

blueprints_to_register = [
    (auth_bp, '/api/auth'),
    (audits_bp, '/api/audits'),
    (kb_bp, '/api/kb'),
    (admin_bp, '/api/admin'),
    (dashboard_bp, '/api/dashboard'),
    (alerts_bp, '/api/alerts'),
    (agents_bp, '/api/agents'),
]

for bp, url_prefix in blueprints_to_register:
    if bp is None:
        log.warning(f"Skipping blueprint registration for {url_prefix} — blueprint failed to import")
        continue
    try:
        app.register_blueprint(bp, url_prefix=url_prefix)
    except Exception as e:
        log.error(f"Failed to register blueprint {bp.name} at {url_prefix}: {e}", exc_info=True)

# ── Health checks ─────────────────────────────────────────────────────────────
@app.route('/api/health', methods=['GET'])
def health():
    """Shallow health check — fast, no aggregation (Vercel warm-up)."""
    db = get_db()
    ok = db is not None
    return jsonify({
        'status':    'healthy' if ok else 'degraded',
        'database':  'connected' if ok else 'disconnected',
        'timestamp': datetime.now(timezone.utc).isoformat()
    }), (200 if ok else 503)

@app.route('/api/health/deep', methods=['GET'])
def health_deep():
    """Deep health check — ensures MongoDB Atlas Vector Search is functional."""
    status = get_db_status()
    db_connected = status.get('connected', False)
    
    return jsonify({
        'status':       'healthy' if db_connected else 'degraded',
        'mongodb':      status,
        # RAG strictly uses Atlas Vector Search to avoid Vercel SQLite exhaustion
        'vector_store': 'connected' if status.get('atlas_vector_index') else 'degraded',
        'timestamp':    datetime.now(timezone.utc).isoformat()
    }), (200 if db_connected else 503)

@app.route('/api/config/social', methods=['GET'])
def get_social_config():
    """Return public configurations."""
    return jsonify({'github': GITHUB_URL}), 200

# ── Authentication Helper ─────────────────────────────────────────────────────
def verify_http_only_jwt() -> bool:
    """
    Strictly enforces HTTP-Only cookie JWT validation for MVC routing.
    Protects against XSS token theft.
    """
    token = request.cookies.get('access_token')
    if not token:
        return False
    try:
        jwt.decode(token, JWT_SECRET, algorithms=["HS256"])
        return True
    except (jwt.ExpiredSignatureError, jwt.InvalidTokenError):
        return False

# ── MVC Protected UI Routes ───────────────────────────────────────────────────
@app.route('/dashboard', methods=['GET'])
def dashboard():
    if not verify_http_only_jwt():
        return redirect(url_for('index'))
    return render_template('dashboard.html')

@app.route('/audit', methods=['GET'])
def audit():
    if not verify_http_only_jwt():
        return redirect(url_for('index'))
    return render_template('audit.html')

@app.route('/knowledge-base', methods=['GET'])
def knowledge_base():
    if not verify_http_only_jwt():
        return redirect(url_for('index'))
    # Enforce server-side RBAC: only admins may access KB UI
    token = request.cookies.get('access_token')
    payload = decode_token(token) if token else None
    if not payload or payload.get('role') != 'admin':
        return redirect(url_for('dashboard'))
    return render_template('knowledge-base.html')

@app.route('/agents', methods=['GET'])
def agents():
    if not verify_http_only_jwt():
        return redirect(url_for('index'))
    # Enforce server-side RBAC: only admins may access Agents UI
    token = request.cookies.get('access_token')
    payload = decode_token(token) if token else None
    if not payload or payload.get('role') != 'admin':
        return redirect(url_for('dashboard'))
    return render_template('agents.html')

# ── Public / Static Routes ────────────────────────────────────────────────────
@app.route('/', methods=['GET'])
def index():
    """Serve landing/login page. Redirect to dashboard if already authenticated."""
    if verify_http_only_jwt():
        return redirect(url_for('dashboard'))
    return render_template('index.html')

@app.route('/assets/<path:filename>')
def serve_assets(filename):
    """
    Securely serve static assets.
    Relies on Werkzeug's `send_from_directory` C-level path sanitization
    to prevent directory traversal attacks (e.g., ../../etc/passwd).
    """
    assets_dir = os.path.join(BASE_DIR, 'assets')
    if not os.path.isdir(assets_dir):
        return jsonify({'error': 'Assets directory missing'}), 404
    return send_from_directory(assets_dir, filename, max_age=3600)
# -- Deterministic custom static routes (consistent with routes.create_app)
@app.route('/style.css', methods=['GET'])
def serve_style():
    project_root = os.path.dirname(BASE_DIR)
    STATIC_DIR = os.path.join(project_root, 'static')
    return send_from_directory(STATIC_DIR, 'css/style.css', mimetype='text/css')


@app.route('/script.js', methods=['GET'])
def serve_script():
    project_root = os.path.dirname(BASE_DIR)
    STATIC_DIR = os.path.join(project_root, 'static')
    return send_from_directory(STATIC_DIR, 'js/script.js', mimetype='application/javascript')


@app.route('/auth-init.js', methods=['GET'])
def serve_auth_init():
    project_root = os.path.dirname(BASE_DIR)
    STATIC_DIR = os.path.join(project_root, 'static')
    return send_from_directory(STATIC_DIR, 'js/auth-init.js', mimetype='application/javascript')


@app.route('/favicon.svg', methods=['GET'])
def serve_favicon():
    project_root = os.path.dirname(BASE_DIR)
    STATIC_DIR = os.path.join(project_root, 'static')
    return send_from_directory(STATIC_DIR, 'img/favicon.svg', mimetype='image/svg+xml')


@app.route('/data/<path:filename>')
def serve_data(filename):
    """Serve public data files (policies, sitemap) from the project-level data/ directory."""
    project_root = os.path.dirname(BASE_DIR)
    data_dir = os.path.join(project_root, 'data')

    # Security: only allow safe extensions
    ALLOWED_DATA_EXTS = {'.md', '.json', '.txt'}
    ext = os.path.splitext(filename)[1].lower()
    if ext not in ALLOWED_DATA_EXTS:
        return jsonify({'error': 'Access denied'}), 403

    # Traversal guard
    full = os.path.normpath(os.path.join(data_dir, filename))
    data_abs = os.path.abspath(data_dir)
    if not full.startswith(data_abs + os.sep) and full != data_abs:
        return jsonify({'error': 'Access denied'}), 403

    if not os.path.isfile(full):
        return jsonify({'error': 'File not found'}), 404

    MIME_MAP = {'.md': 'text/markdown', '.json': 'application/json', '.txt': 'text/plain'}
    mime = MIME_MAP.get(ext)
    if mime:
        return send_from_directory(data_dir, filename, mimetype=mime, max_age=3600)
    return send_from_directory(data_dir, filename, max_age=3600)


@app.route('/<path:filename>')
def serve_static(filename):
    """Serve public static assets with unified path resolution."""
    project_root = os.path.dirname(BASE_DIR)
    STATIC_DIR = os.path.join(project_root, 'static')
    static_abs = os.path.abspath(STATIC_DIR)

    # ── Security gates ────────────────────────────────────────────────────
    ALLOWED_EXTS = {'.css', '.js', '.ico', '.png', '.jpg', '.jpeg', '.svg',
                    '.json', '.txt', '.pdf', '.webp', '.gif', '.md'}
    BLOCKED = {'__pycache__', '.git', '.gitignore'}

    ext = os.path.splitext(filename)[1].lower()
    if ext in {'.py', '.env'}:
        return jsonify({'error': 'Access denied'}), 403
    if ext not in ALLOWED_EXTS:
        return jsonify({'error': 'Access denied'}), 403
    if any(b in filename for b in BLOCKED):
        return jsonify({'error': 'Access denied'}), 403

    # ── MIME type map ─────────────────────────────────────────────────────
    MIME_MAP = {'.css': 'text/css', '.js': 'application/javascript',
                '.svg': 'image/svg+xml', '.json': 'application/json'}

    # ── Unified path resolution ───────────────────────────────────────────
    # Strip redundant 'static/' prefix (templates may use /static/css/…)
    clean = filename.replace('\\', '/')
    if clean.startswith('static/'):
        clean = clean[len('static/'):]

    # Build ordered list of candidate relative paths to try
    basename = clean.split('/')[-1]
    EXT_DIRS = {'.css': 'css', '.js': 'js',
                '.png': 'img', '.jpg': 'img', '.jpeg': 'img',
                '.svg': 'img', '.ico': 'img', '.webp': 'img', '.gif': 'img'}

    candidates = [clean]                                       # 1) exact relative path   (css/style.css)
    if ext in EXT_DIRS:
        mapped = f"{EXT_DIRS[ext]}/{basename}"
        if mapped != clean:
            candidates.append(mapped)                          # 2) extension-mapped path  (css/style.css from style.css)
    if ext in {'.json', '.txt', '.pdf', '.md'}:
        candidates.append(f"assets/{basename}")                # 3) assets fallback
    candidates.append(basename)                                # 4) bare filename in root

    for rel in candidates:
        full = os.path.normpath(os.path.join(STATIC_DIR, rel))
        # Directory traversal guard
        if not full.startswith(static_abs + os.sep) and full != static_abs:
            continue
        if os.path.isfile(full):
            safe_rel = os.path.relpath(full, STATIC_DIR).replace('\\', '/')
            mime = MIME_MAP.get(ext)
            if mime:
                return send_from_directory(STATIC_DIR, safe_rel,
                                           mimetype=mime, max_age=3600)
            return send_from_directory(STATIC_DIR, safe_rel, max_age=3600)

    # ── Log suppressing for noisy browser/extension probes ────────────────
    NOISY_PROBES = {'.well-known', 'favicon.ico', 'manifest.json', '.map'}
    is_noisy = any(probe in filename for probe in NOISY_PROBES)
    
    if not is_noisy:
        log.warning("Static file not found", extra={
            "requested_file": filename, "candidates": candidates,
            "static_dir": static_abs
        })
    
    return jsonify({'error': 'File not found'}), 404

# ── Error handlers ───────────────────────────────────────────────────────────
@app.errorhandler(400)
def bad_request(e):
    return jsonify({'error': 'Bad request'}), 400

@app.errorhandler(401)
def unauthorized(e):
    return jsonify({'error': 'Unauthorized', 'message': 'Invalid or missing HTTP-only cookie'}), 401

@app.errorhandler(403)
def forbidden(e):
    return jsonify({'error': 'Forbidden', 'message': 'CSRF validation failed or insufficient permissions'}), 403

@app.errorhandler(404)
def not_found(e):
    if request.path.startswith('/api/'):
        log.debug("API endpoint not found", extra={"path": request.path})
        return jsonify({'error': 'API endpoint not found'}), 404
    # Redirect to landing page for unknown routes
    return redirect(url_for('index'))

@app.errorhandler(500)
def server_error(e):
    log.error("Unhandled server error", extra={
        "error": str(e),
        "path": request.path,
        "method": request.method,
        "remote_ip": request.remote_addr
    })
    return jsonify({'error': 'Internal server error'}), 500

# ── Startup ───────────────────────────────────────────────────────────────────
if __name__ == '__main__':
    log.info("Starting Qualora Quality Auditor", extra={
        "environment": "vercel" if os.getenv("VERCEL_ENV") else "local"
    })
    
    # Startup health check: verify critical services (warn, don't exit — for HF Spaces flexibility)
    db = get_db()
    if db is None:
        log.warning("MongoDB connection unavailable at startup. Ensure MONGODB_URI is set via environment or secrets.")
    else:
        log.info("✓ MongoDB connected. Ready for audit operations.")
        
    log.info("✓ Flask app initialized. Ready to handle requests.")
    # Fix for Windows: Werkzeug's select() crashes with WinError 10038 during concurrent requests
    is_windows = os.name == 'nt'
    port = int(os.getenv("PORT", "8000"))
    log.info(f"Listening on port {port}")
    try:
        app.run(debug=DEBUG, port=port, threaded=not is_windows)
    except KeyboardInterrupt:
        # Graceful local shutdown (Ctrl+C) without emitting a noisy traceback.
        log.info("Shutdown requested by user (KeyboardInterrupt).")