"""
Unlinked servers see only /drb link and /help (server-26#213).

Discord registers slash commands globally, so an unlinked server still lists
the others in its command picker; this gate answers them with how to link
instead of running them. Per-guild command sync would hide them outright but
costs one sync per server per change — not worth it while C2 refuses every
unlinked request anyway (this gate is UX, C2 is the enforcement).

Whether a server is "linked" is C2's answer: its own discord_guilds link, or
DISCORD_UNLINKED_GUILD_ORG_ID when that is set — so with the default
("founding") nothing is gated, exactly as before.
"""
from __future__ import annotations

import time
from typing import Optional

import discord
from discord import app_commands

from app.internal.c2_client import c2
from app.internal.logger import logger

ALWAYS_ALLOWED = frozenset({"drb link", "help"})
LINKED_TTL = 60.0
UNLINKED_TTL = 10.0   # short, so a fresh /drb link (or a web-side link) shows up fast

UNLINKED_TEXT = (
    "This server is not linked to a DRB organization yet.\n"
    "An owner of the DRB organization generates a code under **Settings → Organization → Discord servers**; "
    "then someone with **Manage Server** here runs `/drb link code:<code>`."
)

_cache: dict[int, tuple[float, bool]] = {}


async def is_linked(guild_id: int) -> Optional[bool]:
    """True/False from C2, or None when C2 could not be reached."""
    hit = _cache.get(guild_id)
    if hit and time.monotonic() < hit[0]:
        return hit[1]
    data = await c2.guild_overview(guild_id)
    if data.get("error"):
        return None
    linked = bool(data.get("org_id"))
    _cache[guild_id] = (time.monotonic() + (LINKED_TTL if linked else UNLINKED_TTL), linked)
    return linked


def forget(guild_id: int) -> None:
    _cache.pop(guild_id, None)


class GatedTree(app_commands.CommandTree):
    async def interaction_check(self, interaction: discord.Interaction) -> bool:
        if interaction.guild_id is None:
            return True
        if interaction.type not in (discord.InteractionType.application_command,
                                    discord.InteractionType.autocomplete):
            return True
        cmd = interaction.command
        if cmd is not None and cmd.qualified_name in ALWAYS_ALLOWED:
            return True
        # None = C2 unreachable: let the command run and report that itself.
        if await is_linked(interaction.guild_id) is not False:
            return True
        try:
            if interaction.type is discord.InteractionType.autocomplete:
                await interaction.response.autocomplete([])
            else:
                await interaction.response.send_message(UNLINKED_TEXT, ephemeral=True)
        except discord.HTTPException as e:
            logger.warning(f"unlinked-guild reply failed: {e}")
        return False