# -*- coding: utf-8 -*-
"""The app module, containing the app factory function."""
import datetime
import decimal
import logging
import os
import sys
from inspect import getmembers
from logging.handlers import RotatingFileHandler
from pathlib import Path

from flask import Flask
from flask import jsonify
from flask import make_response
from flask.blueprints import Blueprint
from flask.cli import click
from flask.json.provider import DefaultJSONProvider

import api.views.entry
from api.extensions import (bcrypt, cache, celery, cors, db, es, login_manager, migrate, rd)
from api.extensions import inner_secrets
from api.lib.perm.authentication.cas import CAS
from api.lib.perm.authentication.oauth2 import OAuth2
from api.lib.secrets.secrets import InnerKVManger
from api.models.acl import User

HERE = os.path.abspath(os.path.dirname(__file__))
PROJECT_ROOT = os.path.join(HERE, os.pardir)
BASE_DIR = Path(__file__).resolve().parent.parent


@login_manager.user_loader
def load_user(user_id):
    """Load user by ID."""
    return User.get_by_id(int(user_id))


class ReverseProxy(object):
    """Wrap the application in this middleware and configure the
    front-end server to add these headers, to let you quietly bind
    this to a URL other than / and to an HTTP scheme that is
    different than what is used locally.

    In nginx:
    location /myprefix {
        proxy_pass http://192.168.0.1:5001;
        proxy_set_header Host $host;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Scheme $scheme;
        proxy_set_header X-Script-Name /myprefix;
        }

    :param app: the WSGI application
    """

    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        script_name = environ.get('HTTP_X_SCRIPT_NAME', '')
        if script_name:
            environ['SCRIPT_NAME'] = script_name
            path_info = environ['PATH_INFO']
            if path_info.startswith(script_name):
                environ['PATH_INFO'] = path_info[len(script_name):]

        scheme = environ.get('HTTP_X_SCHEME', '')
        if scheme:
            environ['wsgi.url_scheme'] = scheme
        return self.app(environ, start_response)


class MyJSONEncoder(DefaultJSONProvider):
    def default(self, o):
        if isinstance(o, (decimal.Decimal, datetime.date, datetime.time)):
            return str(o)

        if isinstance(o, datetime.datetime):
            return o.strftime('%Y-%m-%d %H:%M:%S')

        return o


def create_app(config_object="settings"):
    """Create application factory, as explained here: http://flask.pocoo.org/docs/patterns/appfactories/.

    :param config_object: The configuration object to use.
    """
    app = Flask(__name__.split(".")[0])

    app.config.from_object(config_object)
    app.json = MyJSONEncoder(app)
    configure_logger(app)
    register_extensions(app)
    register_blueprints(app)
    register_error_handlers(app)
    register_shell_context(app)
    register_commands(app)
    CAS(app)
    OAuth2(app)
    app.wsgi_app = ReverseProxy(app.wsgi_app)
    configure_upload_dir(app)

    return app


def configure_upload_dir(app):
    upload_dir = app.config.get('UPLOAD_DIRECTORY', 'uploaded_files')
    common_setting_path = os.path.join(HERE, upload_dir)
    for path in [common_setting_path]:
        if not os.path.exists(path):
            app.logger.warning(f"{path}, not exist, create...")
            os.makedirs(path)

    app.config['UPLOAD_DIRECTORY_FULL'] = common_setting_path


def register_extensions(app):
    """Register Flask extensions."""
    bcrypt.init_app(app)
    cache.init_app(app)
    db.init_app(app)
    cors.init_app(app)
    login_manager.init_app(app)
    migrate.init_app(app, db, directory=f"{BASE_DIR}/migrations")
    rd.init_app(app)
    if app.config.get('USE_ES'):
        es.init_app(app)

    app.config.update(app.config.get("CELERY"))
    celery.conf.update(app.config)

    if app.config.get('SECRETS_ENGINE') == 'inner':
        with app.app_context():
            inner_secrets.init_app(app, InnerKVManger())


def register_blueprints(app):
    for item in getmembers(api.views.entry):
        if item[0].startswith("blueprint") and isinstance(item[1], Blueprint):
            app.register_blueprint(item[1])


def register_error_handlers(app):
    """Register error handlers."""

    def render_error(error):
        """Render error template."""
        import traceback
        app.logger.error(traceback.format_exc())
        error_code = getattr(error, "code", 500)
        if not str(error_code).isdigit():
            error_code = 400

        return make_response(jsonify(message=str(error)), error_code)

    for errcode in app.config.get("ERROR_CODES") or [400, 401, 403, 404, 405, 500, 502]:
        app.errorhandler(errcode)(render_error)

    app.handle_exception = render_error


def register_shell_context(app):
    """Register shell context objects."""

    def shell_context():
        """Shell context objects."""
        return {"db": db, "User": User}

    app.shell_context_processor(shell_context)


def register_commands(app):
    """Register Click commands."""
    for root, _, files in os.walk(os.path.join(HERE, "commands")):
        for filename in files:
            if not filename.startswith("_") and filename.endswith("py"):
                if root not in sys.path:
                    sys.path.insert(1, root)
                command = __import__(os.path.splitext(filename)[0])
                func_list = [o[0] for o in getmembers(command) if isinstance(o[1], click.core.Command)]
                for func_name in func_list:
                    app.cli.add_command(getattr(command, func_name))


def configure_logger(app):
    """Configure loggers."""
    handler = logging.StreamHandler(sys.stdout)
    formatter = logging.Formatter(
        "%(asctime)s %(levelname)s %(pathname)s %(lineno)d - %(message)s")

    if app.debug:
        handler.setFormatter(formatter)
        app.logger.addHandler(handler)

    log_file = app.config['LOG_PATH']
    if log_file and log_file != "/dev/stdout":
        file_handler = RotatingFileHandler(log_file,
                                           maxBytes=2 ** 30,
                                           backupCount=7)
        file_handler.setLevel(getattr(logging, app.config['LOG_LEVEL']))
        file_handler.setFormatter(formatter)
        app.logger.addHandler(file_handler)
    app.logger.setLevel(getattr(logging, app.config['LOG_LEVEL']))