from flask import Flask, request
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager
from flask_migrate import Migrate
from flask_mail import Mail
from flask_wtf.csrf import CSRFProtect
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address
from werkzeug.middleware.proxy_fix import ProxyFix
from config import config
import os
import logging
from logging.handlers import RotatingFileHandler

db            = SQLAlchemy()
login_manager = LoginManager()
migrate       = Migrate()
mail          = Mail()
csrf          = CSRFProtect()    # initialized here; .init_app() called in create_app()
limiter       = Limiter(
    key_func       = get_remote_address,
    default_limits = [],          # no global limit — applied per-route only
    # Use Redis when REDIS_URL is set in the environment (production multi-worker).
    # Falls back to in-process memory for local development (single-worker only;
    # counters are NOT shared across Gunicorn workers in memory:// mode).
    storage_uri    = os.environ.get('REDIS_URL', 'memory://'),
)


# ── Design A/B test: per-request template overrides (phase48) ────────────────
# A user on the 'modern' design gets templates/modern/<name>.html in place of
# templates/<name>.html whenever that override exists; otherwise the normal
# template is used and only the layout shell + CSS differ.
#
# The rewrite happens in get_template() (not in the loader) so Jinja's template
# cache is keyed on the REWRITTEN name — a cached modern template can never be
# served to a classic user, or vice versa.
from flask.templating import Environment as _FlaskJinjaEnvironment


class ThemedEnvironment(_FlaskJinjaEnvironment):
    """Jinja environment that redirects template names to modern/<name>."""

    # Populated once in create_app() by scanning templates/modern/.
    jqc_modern_templates: set = set()

    def get_template(self, name, parent=None, globals=None):
        if (isinstance(name, str)
                and self.jqc_modern_templates
                and not name.startswith('modern/')):
            candidate = 'modern/' + name
            if candidate in self.jqc_modern_templates:
                from flask import g, has_request_context
                if has_request_context() and getattr(g, 'jqc_theme', 'classic') == 'modern':
                    name = candidate
        return super().get_template(name, parent, globals)


def create_app(config_name='default'):
    app = Flask(__name__)
    # Must be assigned BEFORE app.jinja_env is first touched (it is a cached
    # property), so the themed subclass is the one actually instantiated.
    app.jinja_environment = ThemedEnvironment
    app.config.from_object(config[config_name])

    # ── Reverse-proxy awareness (Nginx) ──────────────────────────────────────
    # Nginx terminates TLS and forwards requests over the loopback interface,
    # setting X-Forwarded-For / X-Forwarded-Proto / X-Forwarded-Host. Without
    # ProxyFix, request.remote_addr is always 127.0.0.1, which collapses every
    # Flask-Limiter key into a single shared bucket (rate limits become global
    # instead of per-client) and makes url_for(_external) emit http:// links.
    # x_for=1 trusts exactly one proxy hop — our own Nginx.
    app.wsgi_app = ProxyFix(app.wsgi_app, x_for=1, x_proto=1, x_host=1)

    db.init_app(app)
    login_manager.init_app(app)
    migrate.init_app(app, db)
    mail.init_app(app)
    csrf.init_app(app)    # enables CSRF protection for all web routes
    limiter.init_app(app) # rate limiting — applied per-route via @limiter.limit()

    login_manager.login_view         = 'auth.login'
    login_manager.login_message      = 'Please log in to access this page.'
    login_manager.login_message_category = 'info'

    # ── Logging setup ────────────────────────────────────────────────────────
    # Configure root logger so that logger.info/error calls in all modules
    # (notifications.py, issues.py, etc.) actually write output.
    # Writes to stdout (captured by journalctl/gunicorn) AND a rotating file.
    if not app.debug or os.environ.get('LOG_TO_FILE'):
        log_level = logging.INFO

        formatter = logging.Formatter(
            '[%(asctime)s] %(levelname)s in %(module)s: %(message)s',
            datefmt='%Y-%m-%d %H:%M:%S',
        )

        # Stream handler — always on; journalctl captures stdout
        stream_handler = logging.StreamHandler()
        stream_handler.setLevel(log_level)
        stream_handler.setFormatter(formatter)

        # Rotating file handler — keeps 5 × 5 MB log files
        log_dir  = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'logs')
        os.makedirs(log_dir, exist_ok=True)
        file_handler = RotatingFileHandler(
            os.path.join(log_dir, 'jqc.log'),
            maxBytes=5 * 1024 * 1024,
            backupCount=5,
        )
        file_handler.setLevel(log_level)
        file_handler.setFormatter(formatter)

        # Apply to both the Flask app logger and the root logger so all
        # getLogger(__name__) calls in sub-modules are captured.
        app.logger.setLevel(log_level)
        app.logger.addHandler(stream_handler)
        app.logger.addHandler(file_handler)

        root_logger = logging.getLogger()
        root_logger.setLevel(log_level)
        if not root_logger.handlers:
            root_logger.addHandler(stream_handler)
            root_logger.addHandler(file_handler)

    # Register csrf_token() as an app-wide Jinja2 global so templates that
    # render manual forms (no WTForms object) can still inject the CSRF token.
    # CSRFProtect (initialized above) is the authoritative guard for web routes;
    # the /api/v1 blueprint is exempted below via csrf.exempt().
    from flask_wtf.csrf import generate_csrf
    app.jinja_env.globals['csrf_token'] = generate_csrf
    app.jinja_env.globals['enumerate']  = enumerate

    # SLA helpers available in all templates
    from app.utils.sla import sla_status, sla_deadline, sla_hours_remaining, SLA_HOURS
    app.jinja_env.globals['sla_status']          = sla_status
    app.jinja_env.globals['sla_deadline']        = sla_deadline
    app.jinja_env.globals['sla_hours_remaining'] = sla_hours_remaining
    app.jinja_env.globals['SLA_HOURS']           = SLA_HOURS

    # Photo URL resolver — routes through the active storage backend so templates
    # work unchanged when the backend flips from local to R2 (see utils/storage.py).
    from app.utils import storage as _storage
    app.jinja_env.globals['media_url'] = _storage.media_url

    # ── Design A/B test wiring (phase48) ──────────────────────────────────
    # Index the modern/ override templates once at boot, so get_template()
    # never has to touch the filesystem per request.
    _modern_root = os.path.join(app.template_folder or 'templates', 'modern')
    if not os.path.isabs(_modern_root):
        _modern_root = os.path.join(app.root_path, _modern_root)
    _modern_set = set()
    if os.path.isdir(_modern_root):
        for _dirpath, _dirnames, _filenames in os.walk(_modern_root):
            for _fn in _filenames:
                if _fn.endswith('.html'):
                    _rel = os.path.relpath(os.path.join(_dirpath, _fn), _modern_root)
                    _modern_set.add('modern/' + _rel.replace(os.sep, '/'))
    ThemedEnvironment.jqc_modern_templates = _modern_set
    app.logger.info('UI themes | modern overrides indexed: %s', len(_modern_set))

    from flask import g

    @app.before_request
    def resolve_ui_theme():
        """Stash the active design on `g` for ThemedEnvironment.get_template()."""
        # The mobile API renders no templates and authenticates by JWT — skip it
        # so this never touches the Flask-Login session loader on API traffic.
        if request.path.startswith('/api/'):
            g.jqc_theme = 'classic'
            return
        from flask_login import current_user as _cu
        theme = 'classic'
        try:
            if _cu.is_authenticated:
                theme = _cu.ui_theme or 'classic'
        except Exception:      # DB column missing (migration not yet run)
            theme = 'classic'
        g.jqc_theme = theme if theme in ('classic', 'modern') else 'classic'

    @app.context_processor
    def inject_ui_theme():
        """Give base.html the shell to extend."""
        from app.utils.time_utils import now_eastern
        theme = getattr(g, 'jqc_theme', 'classic')
        _now = now_eastern()
        return {
            'jqc_theme':  theme,
            'jqc_layout': 'layouts/modern.html' if theme == 'modern'
                          else 'layouts/classic.html',
            # Long-form date shown in the modern dashboard header. The day is
            # interpolated rather than formatted with '%-d' — that flag is a
            # glibc extension and raises ValueError on Windows, which would
            # 500 every page (this context processor runs on both themes).
            'now_display': f'{_now.strftime("%A, %B")} {_now.day}, {_now.year}',
        }

    # ── Inject unread notification count into every template context ──────
    # This powers the red badge on the navbar bell icon without requiring
    # individual routes to pass the count manually.
    from flask_login import current_user

    @app.context_processor
    def inject_notification_count():
        if not current_user.is_authenticated:
            return {
                'unread_notification_count':  0,
                'pending_verification_count': 0,
                'open_support_tickets_count': 0,
            }

        # ── Unread notification count (all roles) ──────────────────────────
        # Computed first, in its own try/except, so a failure in the
        # director-specific queries below never zeroes out the bell badge.
        try:
            from app.models.notification import Notification
            unread = Notification.query.filter_by(
                user_id=current_user.id, is_read=False
            ).count()
        except Exception as exc:
            import logging as _logging
            _logging.getLogger(__name__).warning(
                'inject_notification_count: unread query failed: %s', exc
            )
            unread = 0

        # ── Director/admin-only counts ─────────────────────────────────────
        pv_count    = 0
        open_support = 0
        if current_user.role in ('admin', 'director'):
            try:
                from app.models.issue import Issue
                pv_count = Issue.query.filter_by(
                    status='pending_verification'
                ).count()
            except Exception as exc:
                import logging as _logging
                _logging.getLogger(__name__).warning(
                    'inject_notification_count: pv_count query failed: %s', exc
                )
            try:
                from app.models.support import SupportTicket
                open_support = SupportTicket.query.filter_by(status='open').count()
            except Exception as exc:
                import logging as _logging
                _logging.getLogger(__name__).warning(
                    'inject_notification_count: support_tickets query failed: %s', exc
                )

        return {
            'unread_notification_count':  unread,
            'pending_verification_count': pv_count,
            'open_support_tickets_count': open_support,
        }

    os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)

    from app.routes import auth, dashboard, inspections, templates, reports, facilities
    from app.routes import issues          # Phase 3
    from app.routes import notifications   # Notification system
    from app.routes import audit           # Audit Trail
    from app.routes import projects        # Phase 1/2 — Project management
    from app.routes import customers       # Phase 5 — Customer management
    from app.routes import scheduled_reports  # Phase 6 — Scheduled reports
    from app.routes import support         # Support chat + admin tickets
    from app.routes import broadcast       # Admin broadcast notifications
    from app.routes import devices         # Admin device registry
    from app.routes import public          # Public facility QR pages (no login)
    from app.routes import scheduled_inspections  # Planned/recurring inspections
    from app.routes import ui              # phase48 — design A/B test + new pages

    app.register_blueprint(auth.bp)
    app.register_blueprint(dashboard.bp)
    app.register_blueprint(inspections.bp)
    app.register_blueprint(templates.bp)
    app.register_blueprint(reports.bp)
    app.register_blueprint(facilities.bp)
    app.register_blueprint(issues.bp)
    app.register_blueprint(notifications.bp)
    app.register_blueprint(audit.bp)
    app.register_blueprint(projects.bp)
    app.register_blueprint(customers.bp)
    app.register_blueprint(scheduled_reports.bp)
    app.register_blueprint(support.bp)
    app.register_blueprint(broadcast.bp)
    app.register_blueprint(devices.bp)
    app.register_blueprint(public.bp)
    app.register_blueprint(scheduled_inspections.bp)
    app.register_blueprint(ui.bp)

    # ── Enrollment form (self-contained — see app/enrollment/__init__.py) ────
    # Deliberately NOT part of the app's data model: it owns its own templates
    # and stores submissions as JSON files, so it touches no table and needs no
    # migration. Registered last because nothing else depends on it.
    from app.enrollment import register_enrollment
    register_enrollment(app)

    # ── Mobile API (Phase 7 / Phase A / Phase B / Phase C) ───────────────────
    # The /api/v1 blueprint group uses JWT Bearer tokens — no CSRF cookies needed.
    #
    # Flask-WTF's _is_exempt() checks whether the *leaf* blueprint object
    # is in _exempt_blueprints.  Exempting the parent api_bp does NOT cascade
    # to sub-blueprints.  Each child blueprint must be exempted individually.
    from app.api import register_api, api_bp
    from app.api.auth          import bp as _api_auth_bp
    from app.api.facilities    import bp as _api_facilities_bp
    from app.api.templates     import bp as _api_templates_bp
    from app.api.inspections   import bp as _api_inspections_bp
    from app.api.issues        import bp as _api_issues_bp
    from app.api.photos        import bp as _api_photos_bp
    from app.api.notifications import bp as _api_notifications_bp
    from app.api.stats         import bp as _api_stats_bp
    from app.api.comments      import bp as _api_comments_bp
    from app.api.scheduled      import bp as _api_scheduled_bp
    csrf.exempt(_api_auth_bp)
    csrf.exempt(_api_facilities_bp)
    csrf.exempt(_api_templates_bp)
    csrf.exempt(_api_inspections_bp)
    csrf.exempt(_api_issues_bp)
    csrf.exempt(_api_photos_bp)
    csrf.exempt(_api_notifications_bp)
    csrf.exempt(_api_stats_bp)
    csrf.exempt(_api_comments_bp)
    csrf.exempt(_api_scheduled_bp)
    register_api(app)

    # ── Security response headers ─────────────────────────────────────────
    # Applied to every response. Blocks clickjacking, MIME sniffing, and
    # obvious XSS vectors without breaking Bootstrap CDN / Google Fonts.
    # Allow R2 presigned photo URLs in the CSP img-src when the s3 storage
    # backend is configured. Derived from R2_ENDPOINT_URL (the presigned URL
    # host is the same R2 account endpoint), so nothing is hardcoded and the
    # local backend is unaffected.
    _r2_img_src = ''
    _r2_endpoint = app.config.get('R2_ENDPOINT_URL')
    if _r2_endpoint:
        from urllib.parse import urlparse
        _r2_host = urlparse(_r2_endpoint).netloc
        if _r2_host:
            _r2_img_src = f' https://{_r2_host}'

    @app.after_request
    def set_security_headers(response):
        response.headers.setdefault('X-Content-Type-Options', 'nosniff')
        response.headers.setdefault('X-Frame-Options', 'SAMEORIGIN')
        response.headers.setdefault('Referrer-Policy', 'strict-origin-when-cross-origin')
        # Only asserted over an actual HTTPS request — ProxyFix (x_proto=1) makes
        # request.is_secure reflect the real client-facing scheme behind Nginx,
        # so this never fires for plain-HTTP local/dev requests.
        if request.is_secure:
            response.headers.setdefault(
                'Strict-Transport-Security', 'max-age=31536000; includeSubDomains'
            )
        response.headers.setdefault(
            'Content-Security-Policy',
            "default-src 'self'; "
            "script-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; "
            "style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net https://fonts.googleapis.com; "
            "font-src 'self' data: https://fonts.gstatic.com https://cdn.jsdelivr.net; "
            f"img-src 'self' data: blob: https://maps.gstatic.com https://maps.googleapis.com{_r2_img_src}; "
            "connect-src 'self' https://cdn.jsdelivr.net; "
            "frame-src https://maps.google.com https://www.google.com; "
            "frame-ancestors 'none';"
        )
        return response

    # ── Error handler: 413 Request Entity Too Large ───────────────────────
    # Nginx can return 413 before Flask sees the request; this handler covers
    # the Flask-side rejection and gives users a clear, actionable message
    # with a redirect back into the inspection workflow.
    from werkzeug.exceptions import RequestEntityTooLarge

    @app.errorhandler(RequestEntityTooLarge)
    @app.errorhandler(413)
    def handle_413(e):
        from flask import request as flask_request, flash as flask_flash, redirect, url_for
        flask_flash(
            f'The uploaded file(s) are too large. '
            f'Please reduce the photo size or upload fewer photos at once '
            f'(maximum {app.config["MAX_CONTENT_LENGTH"] // (1024 * 1024)}MB per submission).',
            'danger'
        )
        # Redirect back to the referring page if available, otherwise dashboard
        referrer = flask_request.referrer
        return redirect(referrer or url_for('dashboard.index')), 302

    return app