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

from flask import Flask
from flask import make_response, jsonify
from flask.blueprints import Blueprint
from flask.cli import click

import api.views
from api.extensions import (
    bcrypt,
    cors,
    cache,
    db,
    login_manager,
    migrate,
    celery,
    rd,
    es
)
from api.flask_cas import CAS
from api.models.acl import User

HERE = os.path.abspath(os.path.dirname(__file__))
PROJECT_ROOT = os.path.join(HERE, os.pardir)
API_PACKAGE = "api"


@login_manager.user_loader
def load_user(user_id):
    """Load user by ID."""
    return User.get_by(uid=int(user_id), first=True, to_dict=False)


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)


def create_app(config_object="{0}.settings".format(API_PACKAGE)):
    """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)
    register_extensions(app)
    register_blueprints(app)
    register_error_handlers(app)
    register_shell_context(app)
    register_commands(app)
    configure_logger(app)
    CAS(app)
    app.wsgi_app = ReverseProxy(app.wsgi_app)
    return app


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)
    rd.init_app(app)
    if app.config.get("USE_ES"):
        es.init_app(app)
    celery.conf.update(app.config)


def register_blueprints(app):
    for item in getmembers(api.views):
        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)
        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"):
                module_path = os.path.join(API_PACKAGE, root[root.index("commands"):])
                if module_path not in sys.path:
                    sys.path.insert(1, module_path)
                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']
    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']))