#!/usr/bin/env python3

"""
matrix-redact: Delete all messages and media a user has sent in a matrix room.
"""

import random
import math
import asyncio
import argparse
import getpass
import sys
import subprocess
from nio import(
        AsyncClient,
        MatrixRoom,
        LoginResponse,
        RoomInfo,
        MessageDirection,
        RedactedEvent,
        RedactionEvent,
        RoomMessagesError,
        RoomRedactError,

        RoomMemberEvent,
        RoomCreateEvent,
        RoomEncryptionEvent,
        RoomGuestAccessEvent,
        RoomHistoryVisibilityEvent,
        RoomJoinRulesEvent,
        PowerLevelsEvent,

        responses
)
from typing import Optional


async def select_room(client: AsyncClient, sync_response) -> MatrixRoom:
    rooms = []
    for room_id, room in client.rooms.items():
        if room_id in sync_response.rooms.join:
            rooms.append({
                "room_id": room_id,
                "display_name": room.display_name,
            })
            print(f"{rooms[-1]['room_id']} | {rooms[-1]['display_name']}")

    selection = input("\nManually type the full room ID to which redaction will be performed: ")
    for room in rooms:
        if room['room_id'] == selection:
            print(f"{selection} will be redacted")
            return room
    print(f"{selection} is invalid. ")
    return None

async def client_login() -> Optional[AsyncClient]:
    uid = input("Full user ID (eg. @user:matrix.server.com): ")
    upass = getpass.getpass(f"Enter the password for {uid}: ")
    user, hserv = uid[1:].split(':', 1)
    client = AsyncClient(f"https://{hserv}", uid)

    if not isinstance(await client.login(upass), LoginResponse):
        print("could not login, returning None")
        return None
    print("login was successful, returning client.")
    return client

# TODO: Can we fetch the total number of messages from `client.user_id` first, to show % progress?
async def redact_room(client: AsyncClient, room: MatrixRoom) -> None:
    print(f"\nAll events sent by '{client.user_id}' in " +
          f"'{room['room_id']}' ({room['display_name']}) will be deleted.")
    if not input("\n\nIs this room correct? (Type 'Continue') to proceed: ") == "Continue":
        return None

    sync_resp = await client.sync(timeout=30000, full_state=True)
    start_token = sync_resp.rooms.join[room['room_id']].timeline.prev_batch
    current_token = start_token

    tracked = set()
    events_redacted = 0

    while True:
        try:
            print(f"getting messages in {room['room_id']}")
            resp = await client.room_messages(
                    room['room_id'],
                    current_token,
                    limit=500,
                    direction=MessageDirection.back,
            )
        except Exception as e:
            print(f"could not get room message: {e}")
            break
        if isinstance(resp, RoomMessagesError):
            print(f"Could not get room message: {resp}")
            break
        current_token = resp.end
        if len(resp.chunk) == 0:
            print("no more messages to fetch.")
            break

        tasks = []
        for event in resp.chunk:
            event_id = event.event_id

            if (event_id in tracked
            or not hasattr(event, 'sender')
            or event.sender != client.user_id
            or isinstance(event, RedactionEvent)
            or isinstance(event, RedactedEvent)
            or isinstance(event, (RoomMemberEvent,
                                 RoomCreateEvent,
                                 RoomEncryptionEvent,
                                 RoomGuestAccessEvent,
                                 RoomHistoryVisibilityEvent,
                                 RoomJoinRulesEvent,
                                 PowerLevelsEvent))):
                continue

            tracked.add(event_id)

            try:
# NOTE:
  # Fetching room events seems to not have a rate limit (or at least very minimally)
  # Can we therefore in concurrency, fetch events "ahead" whenever redaction limits are returned?

                redact_resp = await client.room_redact(
                        room['room_id'],
                        event_id,
                        reason=""
                )

                if isinstance(redact_resp, RoomRedactError):
                    print(f"Could not redact event {event.event_id} in {room['room_id']}: {redact_resp}")
                else:
                    print(f"Successfully redacted event {event.event_id} in {room['room_id']}")
                    events_redacted += 1
                    print(f"current redactions: {events_redacted}")
                    await asyncio.sleep(1)
            except Exception as e:
                print(f"Error redacting event {event.event_id}: {e}")

    for event in tracked:
        print(event)

    if events_redacted:
        print(f"Total messages redacted: {events_redacted}")
    else:
        print("Could not redact any messages, room is probably redacted already")

async def main(args) -> None:
    print("\n" + "="*80)
    print("WARNING: THIS PROGRAM PERFORMS A PERMANENT DESTRUCTIVE ACTION IN A PROVIDED MATRIX ROOM.\n")
    print("Make absolutely sure you understand what this program does before proceeding.\n\n")

    confirmation = input("Type 'YES I UNDERSTAND' to continue: ")
    if confirmation != "YES I UNDERSTAND":
        print("Exiting.")
        sys.exit(1)

    client = None
    try:
        client = await client_login()
        if not client:
            print("Could not login.")
            sys.exit(1)

        sync_resp = await client.sync(timeout=30000, full_state=True)
        room = await select_room(client, sync_resp)

        if room:
            await redact_room(client, room)

    except Exception as e:
        print(f"Error: {e}")
    finally:
        if client:
            print("logging out.")
            await client.logout()
            await client.close()

if __name__ == "__main__":
    parser = argparse.ArgumentParser(
            description="matrix-mcnt: Matrix Unread Message Count"
    )

    # TODO:
    # - delete just from a specific date range
    # - delete the first a to b messages in DIRECTION

    asyncio.run(main(parser.parse_args()))