##########################################################################
#
# pgAdmin 4 - PostgreSQL Tools
#
# Copyright (C) 2013 - 2015, The pgAdmin Development Team
# This software is released under the PostgreSQL Licence
#
##########################################################################

"""The main pgAdmin module. This handles the application initialisation tasks,
such as setup of logging, dynamic loading of modules etc."""

from flask import Flask, abort, request, current_app
from flask.ext.babel import Babel
from flask.ext.security import Security, SQLAlchemyUserDatastore
from flask_security.utils import login_user
from flask_mail import Mail
from htmlmin.minify import html_minify
from settings.settings_model import db, Role, User
from importlib import import_module
from werkzeug.local import LocalProxy
from pgadmin.utils import PgAdminModule
from werkzeug.utils import find_modules
import sys
import logging

# Configuration settings
import config


class PgAdmin(Flask):

    def find_submodules(self, basemodule):
        for module_name in find_modules(basemodule, True):
            if module_name in self.config['MODULE_BLACKLIST']:
                self.logger.info('Skipping blacklisted module: %s' %
                                module_name)
                continue
            self.logger.info('Examining potential module: %s' % module_name)
            module = import_module(module_name)
            for key, value in module.__dict__.items():
                if isinstance(value, PgAdminModule):
                    yield value


def _find_blueprint():
    if request.blueprint:
        return current_app.blueprints[request.blueprint]

current_blueprint = LocalProxy(_find_blueprint)


def create_app(app_name=config.APP_NAME):
    """Create the Flask application, startup logging and dynamically load
    additional modules (blueprints) that are found in this directory."""
    app = PgAdmin(__name__, static_url_path='/static')
    app.config.from_object(config)

    ##########################################################################
    # Setup logging and log the application startup
    ##########################################################################

    # Add SQL level logging, and set the base logging level
    logging.addLevelName(25, 'SQL')
    app.logger.setLevel(logging.DEBUG)
    app.logger.handlers = []

    # We also need to update the handler on the webserver in order to see request.
    # Setting the level prevents werkzeug from setting up it's own stream handler
    # thus ensuring all the logging goes through the pgAdmin logger.
    logger = logging.getLogger('werkzeug')
    logger.setLevel(logging.INFO)

    # File logging
    fh = logging.FileHandler(config.LOG_FILE)
    fh.setLevel(config.FILE_LOG_LEVEL)
    fh.setFormatter(logging.Formatter(config.FILE_LOG_FORMAT))
    app.logger.addHandler(fh)
    logger.addHandler(fh)

    # Console logging
    ch = logging.StreamHandler()
    ch.setLevel(config.CONSOLE_LOG_LEVEL)
    ch.setFormatter(logging.Formatter(config.CONSOLE_LOG_FORMAT))
    app.logger.addHandler(ch)
    logger.addHandler(ch)

    # Log the startup
    app.logger.info('################################################################################')
    app.logger.info('Starting %s v%s...', config.APP_NAME, config.APP_VERSION)
    app.logger.info('################################################################################')
    app.logger.debug("Python syspath: %s", sys.path)

    ##########################################################################
    # Setup i18n
    ##########################################################################

    # Initialise i18n
    babel = Babel(app)

    app.logger.debug('Available translations: %s' % babel.list_translations())

    @babel.localeselector
    def get_locale():
        """Get the best language for the user."""
        language = request.accept_languages.best_match(config.LANGUAGES.keys())
        return language

    ##########################################################################
    # Setup authentication
    ##########################################################################

    app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///' + config.SQLITE_PATH.replace('\\', '/')

    # Only enable password related functionality in server mode.
    if config.SERVER_MODE is True:
        # TODO: Figure out how to disable /logout and /login
        app.config['SECURITY_RECOVERABLE'] = True
        app.config['SECURITY_CHANGEABLE'] = True

    # Create database connection object and mailer
    db.init_app(app)
    Mail(app)

    # Setup Flask-Security
    user_datastore = SQLAlchemyUserDatastore(db, User, Role)
    Security(app, user_datastore)

    ##########################################################################
    # Load plugin modules
    ##########################################################################
    for module in app.find_submodules('pgadmin'):
        app.logger.info('Registering blueprint module: %s' % module)
        app.register_blueprint(module)

    ##########################################################################
    # Handle the desktop login
    ##########################################################################

    @app.before_request
    def before_request():
        """Login the default user if running in desktop mode"""
        if config.SERVER_MODE is False:
            user = user_datastore.get_user(config.DESKTOP_USER)

            # Throw an error if we failed to find the desktop user, to give
            # the sysadmin a hint. We'll continue to try to login anyway as
            # that'll through a nice 500 error for us.
            if user is None:
                app.logger.error('The desktop user %s was not found in the configuration database.' % config.DESKTOP_USER)
                abort(401)

            login_user(user)

    ##########################################################################
    # Minify output
    ##########################################################################
    @app.after_request
    def response_minify(response):
        """Minify html response to decrease traffic"""
        if config.MINIFY_HTML and not config.DEBUG:
            if response.content_type == u'text/html; charset=utf-8':
                response.set_data(
                    html_minify(response.get_data(as_text=True))
                )

        return response

    @app.context_processor
    def inject_blueprint():
        """Inject a reference to the current blueprint, if any."""
        return {
            'current_blueprint': current_blueprint,
            'menu_items': getattr(current_blueprint, "menu_items", {})}

    ##########################################################################
    # All done!
    ##########################################################################

    app.logger.debug('URL map: %s' % app.url_map)
    return app