"""Sync Slack channel list, members-in-channel, and user list to DB using loops (not recursion)."""
from celery.utils.log import get_task_logger

from sqlmodel import Session

from app.managers.slack import (
    fetch_conversations_list,
    fetch_conversations_members,
    fetch_users_list,
)
from app.managers.team import get_team_by_name
from app.models import ChannelList, MembersInChannel, UserList

logger = get_task_logger(__name__)


def sync_channel_list(session: Session, team_name: str) -> None:
    """Fetch channel list and members per channel from Slack, merge into DB."""
    team = get_team_by_name(session, team_name)
    if not team:
        raise ValueError(f"Team not found: {team_name}")

    logger.info("[%s] Channel sync started", team_name)
    token = team.team_token
    cursor = ""
    total_channels = 0
    total_members = 0
    page = 0

    while True:
        page += 1
        resp = fetch_conversations_list(token, cursor)
        if not resp.get("ok"):
            logger.error("[%s] Failed to fetch channels page %d: %s", team_name, page, resp.get("error"))
            break

        channels = resp.get("channels", [])
        for c in channels:
            total_members += _sync_members_in_channel(session, token, c["id"])
            session.merge(ChannelList(
                channel_id=c["id"],
                channel_name=c.get("name"),
                team_name=team_name,
            ))

        session.commit()
        total_channels += len(channels)
        logger.info("[%s] Channel sync page %d: %d channels", team_name, page, len(channels))

        cursor = (resp.get("response_metadata") or {}).get("next_cursor")
        if not cursor:
            break

    logger.info("[%s] Channel sync complete: %d channels, %d members across %d page(s)",
                team_name, total_channels, total_members, page)


def _sync_members_in_channel(session: Session, token: str, channel_id: str) -> int:
    """Sync members for one channel, returns total member count synced."""
    cursor = ""
    total = 0

    while True:
        resp = fetch_conversations_members(token, channel_id, cursor)
        if not resp.get("ok"):
            logger.error("Failed to fetch members for channel %s: %s", channel_id, resp.get("error"))
            break

        members = resp.get("members", [])
        for m in members:
            session.merge(MembersInChannel(channel_id=channel_id, user_id=m))

        session.commit()
        total += len(members)

        cursor = (resp.get("response_metadata") or {}).get("next_cursor")
        if not cursor:
            break

    return total


def sync_user_list(session: Session, team_name: str) -> None:
    """Fetch user list from Slack, merge into DB."""
    team = get_team_by_name(session, team_name)
    if not team:
        raise ValueError(f"Team not found: {team_name}")

    logger.info("[%s] User sync started", team_name)
    token = team.team_token
    cursor = ""
    total_synced = 0
    total_skipped = 0
    page = 0

    while True:
        page += 1
        resp = fetch_users_list(token, cursor)
        if not resp.get("ok"):
            logger.error("[%s] Failed to fetch users page %d: %s", team_name, page, resp.get("error"))
            break

        members = resp.get("members", [])
        page_synced = 0
        page_skipped = 0
        for i in members:
            profile = i.get("profile") or {}
            email = profile.get("email")
            if not email:
                page_skipped += 1
                continue

            session.merge(UserList(
                user_id=i["id"],
                user_name=i.get("name"),
                tz=i.get("tz") or "",
                email=email,
                team_name=team_name,
            ))
            page_synced += 1

        session.commit()
        total_synced += page_synced
        total_skipped += page_skipped
        logger.info("[%s] User sync page %d: %d synced, %d skipped (no email)",
                    team_name, page, page_synced, page_skipped)

        cursor = (resp.get("response_metadata") or {}).get("next_cursor")
        if not cursor:
            break

    logger.info("[%s] User sync complete: %d synced, %d skipped across %d page(s)",
                team_name, total_synced, total_skipped, page)