# Copyright 2026 Logan Fick
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

"""Bulk-ingests the message history of channels.

Channels are processed by the bot's semaphore-bounded dynamic tasks.
"""

import logging
from typing import TYPE_CHECKING

import discord

from crabstero import metrics
from crabstero.messages import ingest_message

if TYPE_CHECKING:
    from crabstero.bot import Crabstero, IngestableChannel
    from crabstero.database import Database

MAXIMUM_MESSAGES_PER_CHANNEL = (
    50000  # The maximum amount of historical messages to ingest per channel.
)

logger = logging.getLogger(__name__)


def queue_channels_for_ingestion(guild: discord.Guild, bot: Crabstero) -> None:
    """Enqueue every textable channel in a guild for message history ingestion.

    :param guild: The Discord guild whose channels should be ingested.
    :param bot: The bot instance.
    """
    for channel in guild.channels:
        if isinstance(channel, (discord.TextChannel, discord.VoiceChannel)):
            bot.queue_channel_for_ingestion(channel)


async def ingest_channel(
    channel: IngestableChannel,
    db: Database,
) -> None:
    """Bulk-ingest the message history of a given channel.

    End early if permissions do not allow ingesting this channel or if it has
    already been ingested.

    :param channel: The channel to ingest.
    :param db: The database instance.
    """
    if not channel.permissions_for(channel.guild.me).read_message_history:
        logger.warning(
            "[%s] Unable to ingest channel history"
            " due to lacking permissions. Ignoring.",
            channel.id,
        )
        return

    if await db.is_channel_ingested(channel.id):
        return

    await db.mark_channel_ingested(channel.id)

    logger.info("[%s] Starting ingestion of textable channel history.", channel.id)

    with metrics.CHANNEL_INGESTION_DURATION.time():
        count = 0
        async for message in channel.history(limit=MAXIMUM_MESSAGES_PER_CHANNEL):
            count += 1
            await ingest_message(db, message)

    metrics.CHANNEL_INGESTION_MESSAGES.observe(count)

    logger.info(
        "[%s] Ingestion of channel history complete. %d messages iterated.",
        channel.id,
        count,
    )