import logging
import os
from flask import Flask
from app.config import config
from app.extensions import db, login_manager, migrate, csrf
from app.utils.formatters import format_currency, format_percent, format_large_number


def _setup_logging(app):
    """
    Configure the 'app' namespace logger to write to a rotating file AND stderr.

    Uses a pipe-delimited format so the log viewer can parse each field easily:
        2026-06-01 12:00:00|INFO|app.services.teller_service|message text

    The file path comes from LOG_FILE_PATH config (defaults to logs/app.log
    next to the project root). The directory is created automatically.
    """
    import sys
    from logging.handlers import RotatingFileHandler

    app_log = logging.getLogger('app')
    if app_log.handlers:
        return  # already configured (avoids duplicate handlers on reload)

    app_log.setLevel(logging.INFO)
    app_log.propagate = False  # don't double-emit through the root logger

    fmt = logging.Formatter(
        '%(asctime)s|%(levelname)s|%(name)s|%(message)s',
        datefmt='%Y-%m-%d %H:%M:%S',
    )

    # --- rotating file handler (primary — always on) ---
    log_file = app.config.get('LOG_FILE_PATH', '')
    if log_file:
        try:
            os.makedirs(os.path.dirname(log_file), exist_ok=True)
            fh = RotatingFileHandler(
                log_file,
                maxBytes=app.config.get('LOG_MAX_BYTES', 10 * 1024 * 1024),
                backupCount=app.config.get('LOG_BACKUP_COUNT', 5),
                encoding='utf-8',
            )
            fh.setLevel(logging.INFO)
            fh.setFormatter(fmt)
            app_log.addHandler(fh)
        except Exception as exc:
            # Can't open file (permissions, bad path) — fall through to stderr only
            print(f'[pfm] WARNING: could not open log file {log_file!r}: {exc}', file=sys.stderr)

    # --- stderr handler (secondary — also always on so Gunicorn captures it) ---
    sh = logging.StreamHandler(sys.stderr)
    sh.setLevel(logging.INFO)
    sh.setFormatter(fmt)
    app_log.addHandler(sh)

    app_log.info('Logging initialised — file=%s', log_file or '(none)')


def create_app(config_name=None):
    if config_name is None:
        config_name = os.environ.get('FLASK_ENV', 'development')
        config_name = 'production' if config_name == 'production' else 'development'

    app = Flask(__name__)
    app.config.from_object(config[config_name])

    # Wire app.* loggers into Gunicorn's error log (or stderr in dev).
    # basicConfig is a no-op under Gunicorn because Gunicorn already
    # installed root handlers before our app is imported — so we must
    # attach handlers explicitly.
    _setup_logging(app)

    db.init_app(app)
    login_manager.init_app(app)
    migrate.init_app(app, db)
    csrf.init_app(app)

    from app.routes.auth import auth_bp
    from app.routes.dashboard import dashboard_bp
    from app.routes.accounts import accounts_bp
    from app.routes.categories import categories_bp
    from app.routes.transactions import transactions_bp
    from app.routes.budgets import budgets_bp
    from app.routes.goals import goals_bp
    from app.routes.investments import investments_bp
    from app.routes.ai import ai_bp
    from app.routes.reports import reports_bp
    from app.routes.settings import settings_bp
    from app.routes.teller import teller_bp
    from app.routes.logs import logs_bp
    from app.routes.bank_import import bank_import_bp

    app.register_blueprint(auth_bp)
    app.register_blueprint(dashboard_bp)
    app.register_blueprint(accounts_bp)
    app.register_blueprint(categories_bp)
    app.register_blueprint(transactions_bp)
    app.register_blueprint(budgets_bp)
    app.register_blueprint(goals_bp)
    app.register_blueprint(investments_bp)
    app.register_blueprint(ai_bp)
    app.register_blueprint(reports_bp)
    app.register_blueprint(settings_bp)
    app.register_blueprint(teller_bp)
    app.register_blueprint(logs_bp)
    app.register_blueprint(bank_import_bp)

    with app.app_context():
        from app.models import (
            User, Account, Category, Receipt, RecurringRule,
            Transaction, Budget, Goal, GoalContribution,
            Investment, InvestmentTransaction, NetWorthSnapshot,
            AiInsight, FxRate
        )
        from app.models.teller_enrollment import TellerEnrollment, TellerAccount

    app.jinja_env.globals['format_currency'] = format_currency
    app.jinja_env.globals['format_percent'] = format_percent
    app.jinja_env.globals['format_large_number'] = format_large_number

    @app.template_filter('currency')
    def currency_filter(value, symbol=None):
        return format_currency(value, symbol)

    @app.template_filter('percent')
    def percent_filter(value):
        return format_percent(value)

    @app.template_filter('shares')
    def shares_filter(value):
        """Format share quantity — strips trailing zeros, keeps up to 8 decimal places."""
        try:
            f = float(value)
        except (TypeError, ValueError):
            return '0'
        # Format to 8 decimal places then strip trailing zeros
        s = '{:.8f}'.format(f).rstrip('0').rstrip('.')
        return s if s else '0'

    return app