from contextlib import nullcontext
from datetime import datetime, timedelta

from flask import Flask, g, has_app_context, request
from .extensions import default_config


def register_extensions(app):
    from .extensions import db
    db.init_app(app)


def register_jinja2_filters(app):
    import orjson
    with app.app_context():
        @app.template_filter('to_json')
        def to_json(value):
            return orjson.dumps(value).decode('utf-8')

        @app.template_filter('to_duration')
        def to_duration(seconds):
            out = ''
            (days, remainder) = divmod(seconds, 86400)
            (hours, remainder) = divmod(remainder, 3600)
            (minutes, seconds) = divmod(remainder, 60)
            if days:
                out += f'{days:.0f}d '
            if hours:
                out += f'{hours:.0f}h '
            if minutes:
                out += f'{minutes:.0f}m '
            out += f'{seconds:.0f}s'
            return out


def register_blueprints(app):
    with app.app_context():
        # Register blueprints
        from .views import bp as views_bp
        app.register_blueprint(views_bp, url_prefix='/')


def setup_logging(app):
    # Logging
    if app.debug:
        @app.before_request
        def log_before_request():
            g.log_datetime = datetime.now()

        @app.after_request
        def log_after_request(response):
            now = datetime.now()
            delta = (now - g.log_datetime).total_seconds() * 1_000
            dt = now.isoformat().replace('T', ' ').split('.')[0]
            print(f'[{dt}] {request.method} {request.path} -> {response.status} ({delta:.2f}ms)')
            return response


def register_shell_context(app):
    import inspect
    from pprint import pprint

    from flask_sqlalchemy import get_debug_queries

    from demweb import models
    from demweb.extensions import db

    @app.shell_context_processor
    def make_shell_context():
        return {
            'app': app,
            'db': db,
            'query': get_debug_queries,
            'print': pprint,
            **dict(inspect.getmembers(models, inspect.isclass))
        }


def fix_sqlalchemy_uwsgi_multiprocess_bug(app):
    from demweb.extensions import db

    def _dispose_db_pool():
        print('uWSGI+SQLAlchemy: Disposing forked() db pool!')
        with app.app_context() if not has_app_context() else nullcontext():
            db.engine.dispose()

    try:
        from uwsgidecorators import postfork
        postfork(_dispose_db_pool)
    except ImportError:
        pass


def create_app(test_config=None):
    # Create flask application object
    app = Flask(__name__)

    if test_config is None:
        app.config.update(default_config)
    else:
        app.config.update(test_config)

    register_extensions(app)
    register_jinja2_filters(app)
    register_blueprints(app)
    register_shell_context(app)
    setup_logging(app)
    fix_sqlalchemy_uwsgi_multiprocess_bug(app)

    return app