/**
 * Updates — manages bot changelog/update posts to #updates channel.
 *
 * Usage:
 *   import { Updates } from "@systems/updates";
 *
 *   Updates.list()
 *   Updates.latest()
 *   Updates.get({ version: "v0.8" })
 *   Updates.post({ version: "v0.8", client })
 *   Updates.preview({ version: "v0.8", interaction })
 */

 import fs from "fs";
 import path from "path";
 import { Client, EmbedBuilder, TextChannel, MessageFlags, ChatInputCommandInteraction } from "discord.js";
 import { Store } from "@systems/store";
 import { Paths } from "@paths";
 import { Emoji } from "@systems/emojis";
 import { Config } from "@systems/config";
 import { Logger } from "@systems/logger";
 import { PollUI } from "@ui/poll";
 import { Nation, VoteEntry, PollState } from "@types";
 import { WRank } from "@systems/wrank";
 import { Leaves } from "@systems/leaves";
 import { PersistentMessage } from "@systems/persistent-message";
 import { TGKey } from "@systems/tg-key";
 
 const log = Logger.for("updates");
 
 // ─── Types ────────────────────────────────────────────────────────────────────
 
 interface UpdateItem {
   text:     string;
   emojiKey?: string | null;
 }
 
 interface UpdateSection {
   type:  "new" | "improvement" | "fix" | "technical";
   label: string;
   emoji: string;
   items: UpdateItem[];
 }
 
 interface UpdateExample {
   caption: string;
   type:    "poll";
   layout:  string;
   file:    string;
 }
 
 export interface UpdateEntry {
   version:  string;
   date:     string;
   title:    string;
   layout:   string;
   sections: UpdateSection[];
   examples: UpdateExample[];
 }
 
 interface VersionsIndex {
   latest:   string;
   versions: string[];
 }
 
 interface ExamplePollState {
   slot:      number;
   locked:    boolean;
   confirmed: "yes" | "no" | null;
   yes:       VoteEntry[];
   no:        VoteEntry[];
   wrank?:    {
     characterName: string;
     userKey:       string;
     nation:        Nation;
     currentRank:   number;
     previousRank?: number;
     weeklyPoints:  number;
     tgCount:       number;
   }[];
   leaves?: {
     characterName: string;
     historyKey:    TGKey;
   }[];
 }
 
 // ─── Paths ────────────────────────────────────────────────────────────────────
 
 function updatesDir(): string {
   return Paths.data("updates");
 }
 
 function versionDir(version: string): string {
   return path.join(updatesDir(), version);
 }
 
 function messageIdsPath(): string {
   return path.join(updatesDir(), ".message-ids.json");
 }
 
 // ─── Versions cache ───────────────────────────────────────────────────────────
 
 let _versionsCache: string[] | null = null;
 let _latestCache:   string  | null  = null;
 
 function loadVersionsIndex(): void {
   if (_versionsCache) return;
   const index    = Store.read<VersionsIndex>(path.join(updatesDir(), "versions.json"));
   _versionsCache = index?.versions ?? [];
   _latestCache   = index?.latest   ?? null;
 }
 
 // ─── Embed building ───────────────────────────────────────────────────────────
 
 function buildUpdateEmbed(entry: UpdateEntry): EmbedBuilder {
   const embed = new EmbedBuilder()
     .setTitle(`⚔️ The Arbiter — ${entry.version}  ·  ${entry.date}`)
     .setColor(0xe8a317)
     .setTimestamp();
 
   const lines: string[] = [];
 
   for (const section of entry.sections) {
     lines.push(`${section.emoji} **${section.label}**`);
     for (const item of section.items) {
      const emojiStr    = item.emojiKey ? (Emoji.get(item.emojiKey) || "•") : "•";
      // Only resolve tokens if text contains our <:key:> pattern (no ID)
      const resolvedText = item.text.includes("<:") && item.text.includes(":>")
        ? Emoji.resolveTokens(item.text)
        : item.text;
      lines.push(`${emojiStr} ${resolvedText}`);
    }
     lines.push("");
   }
 
   embed.setDescription(lines.join("\n").trim());
   embed.setFooter({ text: `${entry.version} — ${entry.title}` });
   return embed;
 }
 
 function buildExamplePollState(exampleData: ExamplePollState): PollState {
   const yes = new Map<string, VoteEntry>();
   const no  = new Map<string, VoteEntry>();
 
   for (const entry of exampleData.yes) {
     yes.set(entry.userKey ?? entry.displayName ?? entry.characterName ?? "", entry);
   }
   for (const entry of (exampleData.no ?? [])) {
     no.set(entry.userKey ?? entry.displayName ?? "", entry);
   }
 
   return { slot: exampleData.slot, locked: exampleData.locked, confirmed: exampleData.confirmed, yes, no };
 }
 
 function injectMockWrank(exampleData: ExamplePollState): (() => void) | null {
   if (!exampleData.wrank?.length) return null;
 
   const week     = WRank.currentWeek();
   const original = JSON.parse(JSON.stringify(week.entries));
 
   week.entries[Nation.Capella] = [];
   week.entries[Nation.Procyon] = [];
 
   for (const e of exampleData.wrank) {
     const nation = e.nation === Nation.Capella ? Nation.Capella : Nation.Procyon;
     week.entries[nation].push({
       userKey:      e.userKey,
       characterName: e.characterName,
       class:         "WI" as any,
       nation,
       weeklyPoints:  e.weeklyPoints,
       tgCount:       e.tgCount,
       currentRank:   e.currentRank,
       previousRank:  e.previousRank,
     });
   }
 
   return () => {
     week.entries[Nation.Capella] = original[Nation.Capella] ?? [];
     week.entries[Nation.Procyon] = original[Nation.Procyon] ?? [];
   };
 }
 
 function injectMockLeaves(exampleData: ExamplePollState): (() => void) | null {
   if (!exampleData.leaves?.length) return null;
   for (const l of exampleData.leaves) {
     Leaves.mark({ characterName: l.characterName, ownerKey: "example", historyKey: l.historyKey as any, markedBy: "example" });
   }
   return () => {
     for (const l of exampleData.leaves!) {
       Leaves.unmark({ characterName: l.characterName, historyKey: l.historyKey as any });
     }
   };
 }
 
 // ─── Updates namespace ────────────────────────────────────────────────────────
 
 export const Updates = {
   list(): string[] {
     loadVersionsIndex();
     return _versionsCache ?? [];
   },
 
   latest(): string | null {
     loadVersionsIndex();
     return _latestCache;
   },
 
   get({ version }: { version: string }): UpdateEntry | null {
     return Store.read<UpdateEntry>(path.join(versionDir(version), "update.json"));
   },
 
   buildEmbeds(entry: UpdateEntry): EmbedBuilder[] {
     const embeds: EmbedBuilder[] = [buildUpdateEmbed(entry)];
 
     for (const example of entry.examples) {
       const examplePath = path.join(versionDir(entry.version), example.file);
       const exampleData = Store.read<ExamplePollState>(examplePath);
       if (!exampleData) continue;
 
       const cleanupWrank  = injectMockWrank(exampleData);
       const cleanupLeaves = injectMockLeaves(exampleData);
 
       try {
         PollUI.setLayout(example.layout);
         const state        = buildExamplePollState(exampleData);
         const exampleEmbed = PollUI.buildEmbed(state, { 
          overrideLockMsg: `🪲 ${example.caption}`,
          historyKey: exampleData.leaves?.[0]?.historyKey
        });
         exampleEmbed.setTitle(`📋 Example — ${example.caption}`);
         embeds.push(exampleEmbed);
       } finally {
         cleanupWrank?.();
         cleanupLeaves?.();
         PollUI.setLayout(Config.get({ section: "poll", key: "layout" }));
       }
     }
 
     return embeds;
   },
 
   async post({ version, client }: { version: string; client: Client }): Promise<void> {
     const entry = Updates.get({ version });
     if (!entry) { log.error(`Version ${version} not found`); return; }
 
     const channelId = Config.get({ section: "channels", key: "updates" });
     if (!channelId) { log.error("updates channel not configured"); return; }
 
     const channel   = await client.channels.fetch(channelId) as TextChannel;
     const embeds    = Updates.buildEmbeds(entry);
     const messageId = PersistentMessage.get({ store: "updates", key: version });
 
     log.debug(`post: version=${version} messageId=${messageId} idsPath=${messageIdsPath()}`);

     if (messageId) {
       try {
         const msg = await channel.messages.fetch(messageId);
         await msg.edit({ embeds });
         log.info(`Edited ${version} (${messageId})`);
         return;
       } catch {
         log.warn(`Could not edit ${messageId}, posting new`);
         PersistentMessage.delete({ store: "updates", key: version });
       }
     }
 
     const msg = await channel.send({ embeds });
     PersistentMessage.set({ store: "updates", key: version, messageId: msg.id });
     log.info(`Posted ${version} (${msg.id})`);
   },
 
   async preview({ version, interaction }: {
     version:     string;
     interaction: ChatInputCommandInteraction;
   }): Promise<void> {
     const entry = Updates.get({ version });
     if (!entry) {
       await interaction.editReply("❌ Version not found.");
       return;
     }
     const embeds = Updates.buildEmbeds(entry);
     await interaction.editReply({ embeds });
   },
 };