import logging
from dataclasses import dataclass
from typing import List, Optional

import discord

log = logging.getLogger(__name__)


@dataclass
class Target:
    target_id: int
    target_type: str  # "guild" | "group_dm" | "dm"
    name: str


async def resolve_friend(client: discord.Client, friend_id: int) -> discord.User:
    """Fetch the target user object so we can display who the script is
    actually reacting to (helps catch a wrong/typo'd friend_id early)."""
    user = client.get_user(friend_id)
    if user is None:
        user = await client.fetch_user(friend_id)
    return user


async def discover_targets(
    client: discord.Client, friend: discord.User, manual_guild_ids: Optional[List[int]] = None
) -> List[Target]:
    friend_id = friend.id
    targets: List[Target] = []
    guild_ids_seen = set()

    try:
        profile = await friend.profile(with_mutual_guilds=True, with_mutual_friends=False, with_mutual_friends_count=False)
        for mutual in (profile.mutual_guilds or []):
            guild = client.get_guild(mutual.id)
            name = guild.name if guild else f"Unknown Guild {mutual.id}"
            targets.append(Target(mutual.id, "guild", name))
            guild_ids_seen.add(mutual.id)
    except discord.NotFound:
        log.warning(
            "No mutual guild/friend relationship visible for user %s "
            "(profile lookup requires already being friends or sharing a server). "
            "Relying on manual_guild_ids and group DMs only.",
            friend_id,
        )
    except discord.HTTPException:
        log.warning("Mutual-guilds profile lookup failed; falling back to manual_guild_ids only", exc_info=True)

    for guild_id in (manual_guild_ids or []):
        if guild_id in guild_ids_seen:
            continue
        guild = client.get_guild(guild_id)
        name = guild.name if guild else f"Manual Guild {guild_id}"
        targets.append(Target(guild_id, "guild", name))
        guild_ids_seen.add(guild_id)

    try:
        dm_channel = friend.dm_channel or await friend.create_dm()
        targets.append(Target(dm_channel.id, "dm", f"DM with {friend}"))
    except discord.HTTPException:
        log.warning("Failed to open the 1:1 DM channel with %s", friend, exc_info=True)

    for channel in client.private_channels:
        if isinstance(channel, discord.GroupChannel) and any(u.id == friend_id for u in channel.recipients):
            name = channel.name or ", ".join(u.name for u in channel.recipients)
            targets.append(Target(channel.id, "group_dm", name))

    return targets