import { AutocompleteInteraction } from "discord.js";
import { resolveUser } from "@systems/users";
import { getCharacters } from "@systems/characters";
import { Config } from "@systems/config";
import { Emoji } from "@systems/emojis";
import { CharacterRegistry } from "@registry/character-registry";
import { UserRegistry } from "@registry/user-registry";
import { Paths } from "@helpers/paths";
import { Nation } from "@types";
import { NATION_UNICODE } from "@systems/nations";
import { autocompleteLayout } from "@subcommands/tg-config/set-layout";
import { UpdatesCommands } from "@subcommands/admin/updates";
import { ResultCommands }      from "@subcommands/admin/result-post";
import { SetResultLayoutCommands }      from "@subcommands/tg-config/set-result-layout";
import { SetLeaderboardLayoutCommands } from "@subcommands/tg-config/set-leaderboard-layout";
import fs from "fs";

// ─── Usermap cache ────────────────────────────────────────────────────────────
let _usermapCache: Record<string, any> | null = null;

function getUsermapCache(): Record<string, any> {
  if (!_usermapCache) {
    try { _usermapCache = JSON.parse(fs.readFileSync(Paths.data("usermap.json"), "utf8")); }
    catch { _usermapCache = {}; }
  }
  return _usermapCache!;
}

export function invalidateUsermapCache(): void { _usermapCache = null; }

// ─── Autocomplete subsets ─────────────────────────────────────────────────────

async function autocompleteCharNames(
  interaction: AutocompleteInteraction,
  focused: string,
  nation?: Nation | null  // optional — if provided, filter by nation
): Promise<void> {
  const member = await interaction.guild!.members.fetch(interaction.user.id);
  const user   = await resolveUser(member);

  // For bringer set — scan all chars by nation, no user filter needed
  if (nation !== undefined) {
    const all = CharacterRegistry.all();
    const results = all
      .filter((c) => !nation || c.nation === nation)
      .filter((c) => c.name.toLowerCase().includes(focused.toLowerCase()))
      .map((c) => {
        const nationEmoji = c.nation ? (NATION_UNICODE[c.nation] || c.nation) : "";
        return { name: `${c.class} ${c.level} ${c.name} ${nationEmoji}`.trim(), value: c.name };
      })
      .slice(0, 25);
    return interaction.respond(results);
  }

  if (!user.userKey) return interaction.respond([]);

  // Own chars
  const ownChars = getCharacters(user.userKey).map((c) => {
    const nationEmoji = c.nation ? (Emoji.nation(c.nation) || c.nation) : "";
    return {
      name:  `${c.class} ${c.level} ${c.name} ${nationEmoji}`.trim(),
      value: c.name,
    };
  });

  // Shared chars
  const sharedChars = CharacterRegistry.sharedWith(user.userKey).map(({ char }) => {
    const nationEmoji = char.nation ? (Emoji.nation(char.nation) || char.nation) : "";
    return {
      name:  `${char.class} ${char.level} ${char.name} 🔗 ${nationEmoji}`.trim(),
      value: char.name,
    };
  });

  const all = [...ownChars, ...sharedChars]
    .filter((c) => c.name.toLowerCase().includes(focused.toLowerCase()))
    .slice(0, 25);

  await interaction.respond(all);
}

async function autocompleteUserKeys(
  interaction: AutocompleteInteraction,
  focused: string
): Promise<void> {
  try {
    const usermap = getUsermapCache();
    const choices = Object.entries(usermap)
      .map(([, entry]: [string, any]) => {
        const fileKey = typeof entry === "string" ? entry : entry.file;
        const alias   = typeof entry === "object" ? (entry.aliases?.[0] ?? fileKey) : fileKey;
        return { name: `${alias} (${fileKey})`, value: fileKey };
      })
      .filter((c) => c.name.toLowerCase().includes(focused.toLowerCase()))
      .slice(0, 25);
    await interaction.respond(choices);
  } catch {
    await interaction.respond([]);
  }
}

async function autocompleteSlots(
  interaction: AutocompleteInteraction,
  focused: string
): Promise<void> {
  const slots = Config.get({ section: "poll", key: "slots" })
    .filter((s) => s.active)
    .map((s) => ({ name: `${s.tgHour}:00`, value: String(s.tgHour) }))
    .filter((s) => s.name.includes(focused));
  await interaction.respond(slots);
}

// ─── Router ───────────────────────────────────────────────────────────────────

export async function handleAutocomplete(interaction: AutocompleteInteraction): Promise<void> {
  try {
    const focused      = interaction.options.getFocused(true);
    const optionName   = focused.name;
    const focusedValue = focused.value as string;
    const sub          = interaction.options.getSubcommand(false);
    const subGroup     = interaction.options.getSubcommandGroup(false);

    if (optionName === "char_name") {
      // Bringer set — filter by selected nation
      if (sub === "set" && subGroup === "bringer") {
        const nation = interaction.options.getString("nation") as Nation | null;
        return await autocompleteCharNames(interaction, focusedValue, nation);
      }
      return await autocompleteCharNames(interaction, focusedValue);
    }

    if (optionName === "name")  return await autocompleteUserKeys(interaction, focusedValue);
    if (optionName === "slot")  return await autocompleteSlots(interaction, focusedValue);
    if (optionName === "owner") return await autocompleteUserKeys(interaction, focusedValue);
    if (optionName === "layout") return await autocompleteLayout(interaction);
    if (optionName === "version") return UpdatesCommands.autocomplete(interaction);
    if (optionName === "history_key") return await ResultCommands.autocompleteHistory(interaction);
    if (optionName === "week_key")    return await ResultCommands.autocompleteWeekKey(interaction);

    if (optionName === "layout") {
      if (sub === "set-result-layout")      return await SetResultLayoutCommands.autocomplete(interaction);
      if (sub === "set-leaderboard-layout") return await SetLeaderboardLayoutCommands.autocomplete(interaction);
      return await autocompleteLayout(interaction); // poll default
    }

    await interaction.respond([]);
  } catch (err) {
    console.error("[autocomplete] error:", err);
    try { await interaction.respond([]); } catch {}
  }
}