import asyncio
import logging
from typing import Optional

import discord

from bot.display import StatsDisplay
from bot.reactor import human_jitter
from bot.storage import Storage

log = logging.getLogger(__name__)


async def undo_all_reactions(client: discord.Client, storage: Storage, display: Optional[StatsDisplay] = None) -> None:
    """Remove every reaction this script has previously logged, then clear those log entries."""
    rows = await asyncio.to_thread(storage.get_all_reactions)
    total = len(rows)
    log.info("Undo: removing %d previously-added reaction(s)...", total)

    removed = 0
    for i, row in enumerate(rows, start=1):
        channel_id = int(row["channel_id"])
        message_id = int(row["message_id"])
        emoji = row["emoji"]
        should_clear_log = True

        if display is not None:
            display.set_active_target(row["target_id"])
            display.set_status(f"Removing reaction from message {message_id} ({i}/{total})...")

        try:
            channel = client.get_channel(channel_id) or await client.fetch_channel(channel_id)
            message = await channel.fetch_message(message_id)
            await message.remove_reaction(emoji, client.user)
            removed += 1
            log.info("[%d/%d] Removed reaction from message %s", i, total, message_id)
        except discord.NotFound:
            log.info("[%d/%d] Message/reaction %s already gone, clearing log entry", i, total, message_id)
        except discord.HTTPException:
            log.exception("[%d/%d] Failed to remove reaction from message %s, will retry next run", i, total, message_id)
            should_clear_log = False

        if should_clear_log:
            await asyncio.to_thread(storage.delete_reaction, row["id"])
            if display is not None:
                await display.refresh()

        delay = human_jitter()
        if display is not None:
            display.start_countdown(delay, "next removal")
        await asyncio.sleep(delay)
        if display is not None:
            display.clear_countdown()

    if display is not None:
        display.set_active_target(None)
        display.set_status("Clearing channel resume points and found-message log...")
    cleared = await asyncio.to_thread(storage.clear_scan_state)
    await asyncio.to_thread(storage.reset_message_counts)
    if display is not None:
        display.set_status("Undo complete.")
        await display.refresh()
    log.info(
        "Undo complete: removed %d/%d reaction(s), cleared %d channel resume point(s) — "
        "the next normal run will do a full fresh backlog scan.",
        removed, total, cleared,
    )