from __future__ import annotations

import typing
from dataclasses import dataclass, field
import pygame

from button import Button
from config import HEIGHT, WIDTH, CHAT_SELECTOR_WIDTH, DARKER_BLUE, CHAT_PREVIEW_HEIGHT, WHITE, font, DARK_BLUE, \
    MESSAGE_HEIGHT
import degeon_core as dc

from input_field import TextField
from message import Message


@dataclass
class ActiveChat:
    """
    The widget with the current chat

    Attributes:
        :param chat (dc.Chat): the chat (Rust Chat type)
        :param height (int): the height of the active chat widget
        :param width (int): its width
        :param delta_x (int): distance from the left edge of the application to the left edge of the screen
        :param header_height (int): height of the header (the title)
    """
    chat: dc.Chat
    input_field: TextField = field(default_factory=lambda: TextField())
    send_button: Button = field(default_factory=lambda: Button(height=CHAT_PREVIEW_HEIGHT, width=100, text='Send',
                                                               top_left=(WIDTH - 112, HEIGHT - 85)))
    height: int = HEIGHT
    width: int = WIDTH - CHAT_SELECTOR_WIDTH - 10
    delta_x: int = CHAT_SELECTOR_WIDTH + 10
    header_height: int = int(CHAT_PREVIEW_HEIGHT * 1.5)

    @classmethod
    def new(cls, chat: dc.Chat, **kwargs) -> ActiveChat:
        """
        Create a new `Chat` from a rust Chat object
        :param chat: rusty chat
        :param kwargs: optional other paraeters
        :return: the `Chat`
        """
        return cls(chat=chat, **kwargs)

    def get_messages(self, core: dc.Degeon) -> typing.Iterable[Message]:
        """
        Get an iterator over all messages in this chat in the backwards order
        This function creates a python `message.Message` object from rust instances
        :return: an iterator of `message.Message` objects
        """
        for msg in reversed(self.chat.messages):
            yield Message(text=msg.get_content_py().text, is_from_me=core.check_message_ownership(msg))

    def get_header(self) -> pygame.Surface:
        """
        Render a pygame surface with the header.
        The header is (for now) just a name of the user written on a background

        :return: the header
        """
        surface: pygame.Surface = pygame.Surface((self.width, self.header_height))
        surface.fill(DARK_BLUE)
        name_surface: pygame.Surface = font.render(self.chat.profile.name, True, WHITE)
        surface.blit(name_surface, (20, 20))
        return surface

    def render(self, core: dc.Degeon) -> pygame.Surface:
        """
        Creates a pygame surface and draws the chat on it
        :return: the surface with the chat on it
        """
        surface: pygame.Surface = pygame.Surface((self.width, self.height))
        surface.fill(DARKER_BLUE)

        # Render messages
        # This is the y0 for the last message
        last_message_y = self.height - MESSAGE_HEIGHT * 2
        for i, message in zip(range(30), self.get_messages(core)):
            msg_surface = message.render()
            surface.blit(msg_surface, (0, last_message_y - (MESSAGE_HEIGHT + 30) * (i + 1)))
        # Render header
        header = self.get_header()
        surface.blit(header, (0, 10))
        # Render message input
        input_field_surface: pygame.Surface = self.input_field.render()
        surface.blit(input_field_surface, (0, self.height - input_field_surface.get_height()))
        # Render sending button
        sending_button_surface: pygame.Surface = self.send_button.render()
        surface.blit(sending_button_surface,
                     (self.send_button.top_left[0] - self.delta_x, self.send_button.top_left[1]))
        return surface

    def process_event(self, event: pygame.event.Event) -> typing.Optional[str]:
        """
        Process clicks in the active chat widget. Return a message to send if needed
        :param event: a pygame event
        :return: A message to send if there is one
        """
        self.input_field.process_event(event)
        if self.send_button.process_event(event):
            return self.input_field.collect()