#!/usr/bin/env python3
# -*- coding: utf-8 -*-

# Copyright (C) 2018 Andy Stewart
#
# Author:     Andy Stewart <lazycat.manatee@gmail.com>
# Maintainer: Andy Stewart <lazycat.manatee@gmail.com>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# NOTE
# QtWebEngine will throw error "ImportError: QtWebEngineWidgets must be imported before a QCoreApplication instance is created"
# So we import browser module before start Qt application instance to avoid this error, but we never use this module.
from app.browser.buffer import AppBuffer as NeverUsed # noqa

from PyQt5.QtNetwork import QNetworkProxy
from PyQt5.QtWidgets import QApplication
from core.view import View
from dbus.mainloop.glib import DBusGMainLoop
import dbus
import dbus.service
import importlib
import json
import os

EAF_DBUS_NAME = "com.lazycat.eaf"
EAF_OBJECT_NAME = "/com/lazycat/eaf"

class EAF(dbus.service.Object):
    def __init__(self, args):
        global emacs_width, emacs_height

        dbus.service.Object.__init__(
            self,
            dbus.service.BusName(EAF_DBUS_NAME, bus=dbus.SessionBus()),
            EAF_OBJECT_NAME)

        (emacs_width, emacs_height, proxy_host, proxy_port) = args
        emacs_width = int(emacs_width)
        emacs_height = int(emacs_height)

        self.buffer_dict = {}
        self.view_dict = {}

        self.start_finish()

        self.session_file_path = os.path.expanduser("~/.emacs.d/eaf/session.json")

        # Set HTTP proxy.
        if proxy_host != "" and proxy_port != "":
            proxy = QNetworkProxy()
            proxy.setType(QNetworkProxy.HttpProxy)
            proxy.setHostName(proxy_host)
            proxy.setPort(int(proxy_port))
            QNetworkProxy.setApplicationProxy(proxy)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="ssss", out_signature="s")
    def new_buffer(self, buffer_id, url, app_name, arguments):
        # NOTE: We need use function str convert dbus.String to String,
        # otherwise some library will throw error, such as fitz library.
        return self.create_app(buffer_id, str(url), "app.{0}.buffer".format(str(app_name)), str(arguments))

    @dbus.service.method(EAF_DBUS_NAME, in_signature="sss", out_signature="")
    def update_buffer_with_url(self, module_path, buffer_url, update_data):
        for buffer in list(self.buffer_dict.values()):
            if buffer.module_path == module_path and buffer.url == buffer_url:
                buffer.update_with_data(update_data)
                break

    @dbus.service.method(EAF_DBUS_NAME, in_signature="sss", out_signature="")
    def scroll_buffer(self, view_info, scroll_direction, scroll_type):
        (buffer_id, _, _, _, _) = view_info.split(":")
        if buffer_id in self.buffer_dict:
            self.buffer_dict[buffer_id].scroll(scroll_direction, scroll_type)

    def get_new_browser_window_buffer_id(self):
        import secrets

        return "{0}-{1}-{2}-{3}-{4}-{5}-{6}".format(
            secrets.token_hex(2),
            secrets.token_hex(2),
            secrets.token_hex(2),
            secrets.token_hex(2),
            secrets.token_hex(2),
            secrets.token_hex(2),
            secrets.token_hex(2))

    def create_new_browser_window(self):
        # Generate buffer id same as eaf.el does.
        buffer_id = self.get_new_browser_window_buffer_id()

        # Create buffer for create new browser window.
        app_buffer = self.create_buffer(buffer_id, "http://0.0.0.0", "app.browser.buffer", "")

        # Create emacs buffer with buffer id.
        self.create_new_browser_buffer(buffer_id)

        # Return new QWebEngineView for create new browser window.
        return app_buffer.buffer_widget

    def create_app(self, buffer_id, url, module_path, arguments):
        try:
            self.create_buffer(buffer_id, url, module_path, arguments)

            return ""
        except ImportError:
            import traceback
            traceback.print_exc()
            return "EAF: Something went wrong when trying to import {0}".format(module_path)

    def create_buffer(self, buffer_id, url, module_path, arguments):
        global emacs_width, emacs_height

        # Create application buffer.
        module = importlib.import_module(module_path)
        app_buffer = module.AppBuffer(buffer_id, url, arguments)
        app_buffer.module_path = module_path

        # Add buffer to buffer dict.
        self.buffer_dict[buffer_id] = app_buffer

        # Resize buffer with emacs max window size,
        # view (QGraphicsView) will adjust visual area along with emacs window changed.
        app_buffer.buffer_widget.resize(emacs_width, emacs_height)

        # Monitor buffer signals.
        app_buffer.update_title.connect(self.update_buffer_title)
        app_buffer.open_url.connect(self.open_buffer_url)
        app_buffer.translate_text.connect(self.translate_text)

        # Send message to emacs.
        app_buffer.input_message.connect(self.input_message)

        # Get variables defined in emacs.
        self.get_emacs_var()

        # Handle buffer close request.
        app_buffer.close_buffer.connect(self.request_kill_buffer)

        # Handle message to emacs.
        app_buffer.message_to_emacs.connect(self.message_to_emacs)

        # Handle set emacs var signal.
        app_buffer.set_emacs_var.connect(self.set_emacs_var)

        # Handle eval form in emacs.
        app_buffer.eval_in_emacs.connect(self.eval_in_emacs)

        # Add create new window callback if module is browser
        if module_path == "app.browser.buffer":
            app_buffer.buffer_widget.create_new_browser_window_callback = self.create_new_browser_window

        # Restore buffer session.
        self.restore_buffer_session(app_buffer)

        return app_buffer

    @dbus.service.method(EAF_DBUS_NAME, in_signature="s", out_signature="")
    def update_views(self, args):
        view_infos = args.split(",")

        # Do something if buffer's all view hide after update_views operation.
        old_view_buffer_ids = list(set(map(lambda v: v.buffer_id, self.view_dict.values())))
        new_view_buffer_ids = list(set(map(lambda v: v.split(":")[0], view_infos)))

        # Call all_views_hide interface when buffer's all views will hide.
        # We do something in app's buffer interface, such as videoplayer will pause video when all views hide.
        # Note, we must call this function before last view destroy,
        # such as QGraphicsVideoItem will report "Internal data stream error" error.
        for old_view_buffer_id in old_view_buffer_ids:
            if old_view_buffer_id not in new_view_buffer_ids:
                self.buffer_dict[old_view_buffer_id].all_views_hide()

        # Remove old key from view dict and destroy old view.
        for key in list(self.view_dict):
            if key not in view_infos:
                self.view_dict[key].handle_destroy()
                self.view_dict.pop(key, None)

        # Create new view and udpate in view dict.
        if view_infos != ['']:
            for view_info in view_infos:
                if view_info not in self.view_dict:
                    (buffer_id, _, _, _, _, _) = view_info.split(":")
                    view = View(self.buffer_dict[buffer_id], view_info)
                    self.view_dict[view_info] = view

                    view.trigger_focus_event.connect(self.focus_emacs_buffer)

        # Call some_view_show interface when buffer's view switch back.
        # Note, this must call after new view create, otherwise some buffer,
        # such as QGraphicsVideoItem will report "Internal data stream error" error.
        if view_infos != ['']:
            for new_view_buffer_id in new_view_buffer_ids:
                if new_view_buffer_id not in old_view_buffer_ids:
                    self.buffer_dict[new_view_buffer_id].some_view_show()

        # Adjust buffer size along with views change.
        # Note: just buffer that option `fit_to_view' is False need to adjust,
        # if buffer option fit_to_view is True, buffer render adjust by view.resizeEvent()
        for buffer in list(self.buffer_dict.values()):
            if not buffer.fit_to_view:
                buffer_views = list(filter(lambda v: v.buffer_id == buffer.buffer_id, list(self.view_dict.values())))

                # Adjust buffer size to max view's size.
                if len(buffer_views) > 0:
                    max_view = max(buffer_views, key=lambda v: v.width * v.height)

                    buffer.buffer_widget.resize(max_view.width, max_view.height)
                # Adjust buffer size to emacs window size if not match view found.
                else:
                    buffer.buffer_widget.resize(emacs_width, emacs_height)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="", out_signature="")
    def kill_emacs(self):
        tmp_buffer_dict = {}
        for buffer_id in self.buffer_dict:
            tmp_buffer_dict[buffer_id] = self.buffer_dict[buffer_id]

        for buffer_id in tmp_buffer_dict:
            self.kill_buffer(buffer_id)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="s", out_signature="")
    def kill_buffer(self, buffer_id):
        # Kill all view base on buffer_id.
        for key in list(self.view_dict):
            if buffer_id == self.view_dict[key].buffer_id:
                self.view_dict[key].handle_destroy()
                self.view_dict.pop(key, None)

        # Clean buffer from buffer dict.
        if buffer_id in self.buffer_dict:
            # Save buffer session.
            self.save_buffer_session(self.buffer_dict[buffer_id])

            self.buffer_dict[buffer_id].handle_destroy()
            self.buffer_dict.pop(buffer_id, None)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="ss", out_signature="")
    def execute_function(self, buffer_id, function_name):
        if buffer_id in self.buffer_dict:
            try:
                self.buffer_dict[buffer_id].execute_function(function_name)
            except AttributeError:
                self.message_to_emacs("Cannot execute function: " + function_name)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="ss", out_signature="s")
    def call_function(self, buffer_id, function_name):
        if buffer_id in self.buffer_dict:
            try:
                return self.buffer_dict[buffer_id].call_function(function_name)
            except AttributeError:
                self.message_to_emacs("Cannot call function: " + function_name)
                return ""

    @dbus.service.method(EAF_DBUS_NAME, in_signature="s", out_signature="")
    def action_quit(self, buffer_id):
        if buffer_id in self.buffer_dict:
            self.buffer_dict[buffer_id].action_quit()

    @dbus.service.method(EAF_DBUS_NAME, in_signature="ss", out_signature="")
    def send_key(self, buffer_id, event_string):
        # Send event to buffer when found match buffer.
        if buffer_id in self.buffer_dict:
            self.buffer_dict[buffer_id].fake_key_event(event_string)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="sss", out_signature="")
    def handle_input_message(self, buffer_id, callback_type, callback_result):
        for buffer in list(self.buffer_dict.values()):
            if buffer.buffer_id == buffer_id:
                buffer.handle_input_message(callback_type, callback_result)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="ss", out_signature="")
    def cancel_input_message(self, buffer_id, callback_type):
        for buffer in list(self.buffer_dict.values()):
            if buffer.buffer_id == buffer_id:
                buffer.cancel_input_message(callback_type)

    @dbus.service.method(EAF_DBUS_NAME, in_signature="s", out_signature="")
    def store_emacs_var(self, var_dict_string):
        for var_pair in var_dict_string.split(","):
            (var_name, var_value) = var_pair.split(":")
            for buffer in list(self.buffer_dict.values()):
                buffer.emacs_var_dict[var_name] = var_value
                buffer.update_settings()

    @dbus.service.signal(EAF_DBUS_NAME)
    def focus_emacs_buffer(self, message):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def start_finish(self):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def update_buffer_title(self, buffer_id, title):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def open_buffer_url(self, url):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def translate_text(self, text):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def input_message(self, buffer_id, message, callback_type):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def create_new_browser_buffer(self, buffer_id):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def request_kill_buffer(self, buffer_id):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def message_to_emacs(self, message):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def set_emacs_var(self, var_name, var_value):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def eval_in_emacs(self, elisp_code_string):
        pass

    @dbus.service.signal(EAF_DBUS_NAME)
    def get_emacs_var(self):
        pass

    def save_buffer_session(self, buf):
        # Create config file it not exist.
        if not os.path.exists(self.session_file_path):
            basedir = os.path.dirname(self.session_file_path)
            if not os.path.exists(basedir):
                os.makedirs(basedir)

            with open(self.session_file_path, 'a'):
                os.utime(self.session_file_path, None)

            print("Create session file %s" % (self.session_file_path))

        # Save buffer session to file.
        buf_session_data = buf.save_session_data()
        if buf_session_data != "":
            with open(self.session_file_path, "r+") as session_file:
                # Init session dict.
                session_dict = {}
                try:
                    session_dict = json.load(session_file)
                except ValueError:
                    pass

                # Init module path dict.
                if buf.module_path not in session_dict:
                    session_dict[buf.module_path] = {}

                # Update session data.
                session_dict[buf.module_path].update({buf.url: buf_session_data})

                # Clean session file and update new content.
                session_file.seek(0)
                session_file.truncate(0)
                json.dump(session_dict, session_file)

                print("Save session: ", buf.module_path, buf.url, buf_session_data)

    def restore_buffer_session(self, buf):
        if os.path.exists(self.session_file_path):
            with open(self.session_file_path, "r+") as session_file:
                session_dict = {}
                try:
                    session_dict = json.load(session_file)
                except ValueError:
                    pass

                if buf.module_path in session_dict:
                    if buf.url in session_dict[buf.module_path]:
                        buf.restore_session_data(session_dict[buf.module_path][buf.url])

                        print("Restored session: ", buf.buffer_id, buf.module_path, self.session_file_path)
                    else:
                        print("No session data about %s, no need to restore session." % (buf.url))
                else:
                    print("No data present in session file, no need to restore session.")
        else:
            print("Cannot find %s, no need restore session." % (self.session_file_path))

if __name__ == "__main__":
    import sys
    import signal

    DBusGMainLoop(set_as_default=True) # WARING: only use once in one process

    bus = dbus.SessionBus()
    if bus.request_name(EAF_DBUS_NAME) != dbus.bus.REQUEST_NAME_REPLY_PRIMARY_OWNER:
        print("EAF process has startup.")
    else:
        emacs_width = emacs_height = 0

        app = QApplication(sys.argv)

        eaf = EAF(sys.argv[1:])

        print("EAF process start.")

        signal.signal(signal.SIGINT, signal.SIG_DFL)
        sys.exit(app.exec_())