import { UsageError } from "./errors.js";
import type { Command, CommandContext, Registry } from "./command.js";
import { flagString } from "./command.js";
import { loadConfig } from "./config.js";
import { request } from "./http.js";

/** 共用：載入設定並執行一次 API 請求，把結果印成 JSON。 */
async function call(
  ctx: CommandContext,
  path: string,
  options: { method?: string; body?: unknown; auth?: boolean; print?: boolean } = {},
): Promise<unknown> {
  const { print = true } = options;
  const config = await loadConfig({
    apiUrl: flagString(ctx.args.flags, "api-url"),
    token: flagString(ctx.args.flags, "token"),
  });
  const data = await request(config, path, options);
  if (print) ctx.print(data);
  return data;
}

/**
 * 讀取內容類選項（--content／--prompt／--previous-context）的值。
 * 值為 "-" 時改從 stdin 讀入全部內容（適合多行文字經管線傳入）；
 * stdin 是終端機時直接報用法錯誤，避免掛起等待輸入。
 */
async function readValue(
  flagName: string,
  value: string | undefined,
): Promise<string | undefined> {
  if (value !== "-") return value;
  if (process.stdin.isTTY) {
    throw new UsageError(
      `--${flagName} - 需經管線傳入內容（stdin 是終端機，會無限等待）；用法：cat 檔案 | fox … --${flagName} -`,
    );
  }
  const chunks: Buffer[] = [];
  for await (const chunk of process.stdin) {
    chunks.push(chunk as Buffer);
  }
  return Buffer.concat(chunks).toString("utf8");
}

/** 讀取位置參數並要求非空。 */
function requirePositional(
  positionals: string[],
  index: number,
  name: string,
  usage: string,
): string {
  const value = positionals[index];
  if (value === undefined || !value.trim()) {
    throw new UsageError(`缺少 <${name}>；用法：${usage}`);
  }
  return value.trim();
}

/** 讀取必填的字串選項。 */
async function requireFlag(
  flags: Record<string, string | boolean>,
  flagName: string,
  usage: string,
): Promise<string> {
  const value = await readValue(flagName, flagString(flags, flagName));
  if (value === undefined || !value.trim()) {
    throw new UsageError(`缺少 --${flagName}；用法：${usage}`);
  }
  return value.trim();
}

export function registerAuthCommands(registry: Registry): void {
  registry.add({
    path: ["auth", "status"],
    summary: "查詢登入／SSO 設定（公開端點）",
    usage: "fox auth status",
    run: async (ctx) => {
      await call(ctx, "auth/status");
    },
  });
}

export function registerTokenCommands(registry: Registry): void {
  registry.add({
    path: ["tokens", "verify"],
    summary: "驗證手中 token 是否有效（無效回非零 exit code）",
    usage: "fox tokens verify",
    run: async (ctx) => {
      await call(ctx, "access-tokens/verify", { auth: true });
    },
  });

  registry.add({
    path: ["tokens", "create"],
    summary: "建立新 token（原始值只在這次輸出顯示）",
    usage:
      "fox tokens create --name <名稱> [--expires-at <ISO8601>] [--scopes read,write,generate]",
    run: async (ctx) => {
      const name = flagString(ctx.args.flags, "name");
      if (!name || !name.trim()) {
        throw new UsageError(
          "缺少 --name <名稱>；用法：fox tokens create --name <名稱> [--expires-at <ISO8601>] [--scopes read,write,generate]",
        );
      }
      const expiresAt = flagString(ctx.args.flags, "expires-at");
      if (expiresAt !== undefined && Number.isNaN(Date.parse(expiresAt))) {
        throw new UsageError(`--expires-at 不是有效的 ISO 8601 日期：${expiresAt}`);
      }
      const body: Record<string, unknown> = { name: name.trim() };
      if (expiresAt !== undefined) body.expiresAt = new Date(expiresAt).toISOString();

      const scopes = flagString(ctx.args.flags, "scopes");
      if (scopes !== undefined) {
        const list = scopes
          .split(",")
          .map((s) => s.trim())
          .filter(Boolean);
        const valid = ["read", "write", "generate"];
        const bad = list.filter((s) => !valid.includes(s));
        if (bad.length > 0) {
          throw new UsageError(
            `--scopes 含無效值：${bad.join(",")}（可用：read、write、generate）`,
          );
        }
        body.scopes = list;
      }
      await call(ctx, "access-tokens", { method: "POST", body });
    },
  });

  registry.add({
    path: ["tokens", "list"],
    summary: "列出 token（不含 hash／原始值）",
    usage: "fox tokens list",
    run: async (ctx) => {
      await call(ctx, "access-tokens");
    },
  });

  registry.add({
    path: ["tokens", "revoke"],
    summary: "撤銷 token（冪等）",
    usage: "fox tokens revoke <id>",
    run: async (ctx) => {
      const id = ctx.args.positionals[0];
      const n = Number(id);
      if (id === undefined || !/^\d+$/.test(id) || !Number.isSafeInteger(n)) {
        throw new UsageError("缺少或無效的 token id；用法：fox tokens revoke <id>");
      }
      await call(ctx, `access-tokens/${n}`, { method: "DELETE", print: false });
      ctx.print({ ok: true, id: n });
    },
  });
}

const CHAPTER_USAGE =
  "fox chapters <list|get|create|update|delete> <novelSlug> …（見 fox chapters --help）";
const CHAPTER_STATUSES = ["draft", "published", "hidden"] as const;
const NOVEL_STATUSES = ["draft", "serializing", "completed", "hidden"] as const;

/** 讀取 --status 並驗證值域（draft／published／hidden）。 */
function readChapterStatusFlag(flags: Record<string, string | boolean>): string | undefined {
  const value = flagString(flags, "status");
  if (value === undefined) return undefined;
  if (!CHAPTER_STATUSES.includes(value as (typeof CHAPTER_STATUSES)[number])) {
    throw new UsageError(`--status 不正確（${CHAPTER_STATUSES.join("｜")}）：${value}`);
  }
  return value;
}

/** 讀取 --status 並驗證值域（draft／serializing／completed／hidden）。 */
function readNovelStatusFlag(flags: Record<string, string | boolean>): string | undefined {
  const value = flagString(flags, "status");
  if (value === undefined) return undefined;
  if (!NOVEL_STATUSES.includes(value as (typeof NOVEL_STATUSES)[number])) {
    throw new UsageError(`--status 不正確（${NOVEL_STATUSES.join("｜")}）：${value}`);
  }
  return value;
}

/** 讀取 --sort-order 並驗證為 0–1000000 的整數。 */
function readSortOrderFlag(flags: Record<string, string | boolean>): number | undefined {
  const raw = flagString(flags, "sort-order");
  if (raw === undefined) return undefined;
  const n = Number(raw);
  if (!/^\d+$/.test(raw.trim()) || !Number.isInteger(n) || n < 0 || n > 1_000_000) {
    throw new UsageError(`--sort-order 須為 0–1000000 的整數：${raw}`);
  }
  return n;
}

export function registerNovelCommands(registry: Registry): void {
  registry.add({
    path: ["novels", "get"],
    summary: "查單一作品（公開端點）",
    usage: "fox novels get <slug>",
    run: async (ctx) => {
      const slug = requirePositional(ctx.args.positionals, 0, "slug", "fox novels get <slug>");
      await call(ctx, `novels/${encodeURIComponent(slug)}`);
    },
  });

  registry.add({
    path: ["novels", "list"],
    summary: "列出自己的作品（需授權）",
    usage: "fox novels list",
    run: async (ctx) => {
      await call(ctx, "novels", { auth: true });
    },
  });

  registry.add({
    path: ["novels", "create"],
    summary: "建立作品（需授權；slug 由書名自動生成，衝突時加流水號）",
    usage:
      "fox novels create --title <書名> [--slug <slug>] [--synopsis <簡介>] [--tags <標籤1,標籤2>]",
    run: async (ctx) => {
      const usage =
        "fox novels create --title <書名> [--slug <slug>] [--synopsis <簡介>] [--tags <標籤1,標籤2>]";
      const title = await requireFlag(ctx.args.flags, "title", usage);
      const body: Record<string, unknown> = { title };
      const slug = flagString(ctx.args.flags, "slug");
      if (slug !== undefined) body.slug = slug.trim();
      const synopsis = flagString(ctx.args.flags, "synopsis");
      if (synopsis !== undefined) body.synopsis = synopsis;
      const tags = flagString(ctx.args.flags, "tags");
      if (tags !== undefined) body.tags = tags;
      await call(ctx, "novels", { method: "POST", body, auth: true });
    },
  });

  registry.add({
    path: ["novels", "update"],
    summary: "更新作品（需授權；只傳要改的欄位）",
    usage:
      "fox novels update <slug> [--title <書名>] [--slug <新slug>] [--synopsis <簡介>] [--tags <標籤>] [--status <狀態>]",
    run: async (ctx) => {
      const usage =
        "fox novels update <slug> [--title <書名>] [--slug <新slug>] [--synopsis <簡介>] [--tags <標籤>] [--status <狀態>]";
      const slug = requirePositional(ctx.args.positionals, 0, "slug", usage);
      const body: Record<string, unknown> = {};
      const title = flagString(ctx.args.flags, "title");
      if (title !== undefined) body.title = title.trim();
      const newSlug = flagString(ctx.args.flags, "slug");
      if (newSlug !== undefined) body.slug = newSlug.trim();
      const synopsis = flagString(ctx.args.flags, "synopsis");
      if (synopsis !== undefined) body.synopsis = synopsis;
      const tags = flagString(ctx.args.flags, "tags");
      if (tags !== undefined) body.tags = tags;
      const status = readNovelStatusFlag(ctx.args.flags);
      if (status !== undefined) body.status = status;
      if (Object.keys(body).length === 0) {
        throw new UsageError(`沒有指定任何要更新的欄位；用法：${usage}`);
      }
      await call(ctx, `novels/${encodeURIComponent(slug)}`, {
        method: "PATCH",
        body,
        auth: true,
      });
    },
  });
}

export function registerChapterCommands(registry: Registry): void {
  registry.add({
    path: ["chapters", "list"],
    summary: "列章節（公開僅 published；帶作者 token 可見全部）",
    usage: "fox chapters list <novelSlug>",
    run: async (ctx) => {
      const slug = requirePositional(ctx.args.positionals, 0, "novelSlug", "fox chapters list <novelSlug>");
      // 公開端點：有 token 就帶上（作者本人可見 draft／hidden），沒有也照常呼叫。
      const config = await loadConfig({
        apiUrl: flagString(ctx.args.flags, "api-url"),
        token: flagString(ctx.args.flags, "token"),
      });
      const data = await request(
        config,
        `novels/${encodeURIComponent(slug)}/chapters`,
        config.token ? { auth: true } : {},
      );
      ctx.print(data);
    },
  });

  registry.add({
    path: ["chapters", "get"],
    summary: "查單一章節（draft 僅作者／admin）",
    usage: "fox chapters get <novelSlug> <chapterSlug>",
    run: async (ctx) => {
      const usage = "fox chapters get <novelSlug> <chapterSlug>";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      const chapterSlug = requirePositional(ctx.args.positionals, 1, "chapterSlug", usage);
      const config = await loadConfig({
        apiUrl: flagString(ctx.args.flags, "api-url"),
        token: flagString(ctx.args.flags, "token"),
      });
      const data = await request(
        config,
        `novels/${encodeURIComponent(novelSlug)}/chapters/${encodeURIComponent(chapterSlug)}`,
        config.token ? { auth: true } : {},
      );
      ctx.print(data);
    },
  });

  registry.add({
    path: ["chapters", "create"],
    summary: "建立章節（需授權；slug 由標題生成，狀態預設 draft）",
    usage:
      "fox chapters create <novelSlug> --title <標題> [--slug <slug>] [--content <內容|->] [--sort-order <N>] [--status <狀態>]",
    run: async (ctx) => {
      const usage =
        "fox chapters create <novelSlug> --title <標題> [--slug <slug>] [--content <內容|->] [--sort-order <N>] [--status <狀態>]";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      const title = await requireFlag(ctx.args.flags, "title", usage);
      const body: Record<string, unknown> = { title };
      const slug = flagString(ctx.args.flags, "slug");
      if (slug !== undefined) body.slug = slug.trim();
      const content = await readValue("content", flagString(ctx.args.flags, "content"));
      if (content !== undefined) body.content = content;
      const sortOrder = readSortOrderFlag(ctx.args.flags);
      if (sortOrder !== undefined) body.sortOrder = sortOrder;
      const status = readChapterStatusFlag(ctx.args.flags);
      if (status !== undefined) body.status = status;
      await call(ctx, `novels/${encodeURIComponent(novelSlug)}/chapters`, {
        method: "POST",
        body,
        auth: true,
      });
    },
  });

  registry.add({
    path: ["chapters", "update"],
    summary: "更新章節（需授權；只傳要改的欄位）",
    usage:
      "fox chapters update <novelSlug> <chapterSlug> [--title <標題>] [--slug <slug>] [--content <內容|->] [--sort-order <N>] [--status <狀態>]",
    run: async (ctx) => {
      const usage =
        "fox chapters update <novelSlug> <chapterSlug> [--title <標題>] [--slug <slug>] [--content <內容|->] [--sort-order <N>] [--status <狀態>]";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      const chapterSlug = requirePositional(ctx.args.positionals, 1, "chapterSlug", usage);
      const body: Record<string, unknown> = {};
      const title = flagString(ctx.args.flags, "title");
      if (title !== undefined) body.title = title.trim();
      const slug = flagString(ctx.args.flags, "slug");
      if (slug !== undefined) body.slug = slug.trim();
      const content = await readValue("content", flagString(ctx.args.flags, "content"));
      if (content !== undefined) body.content = content;
      const sortOrder = readSortOrderFlag(ctx.args.flags);
      if (sortOrder !== undefined) body.sortOrder = sortOrder;
      const status = readChapterStatusFlag(ctx.args.flags);
      if (status !== undefined) body.status = status;
      if (Object.keys(body).length === 0) {
        throw new UsageError(`沒有指定任何要更新的欄位；用法：${usage}`);
      }
      await call(
        ctx,
        `novels/${encodeURIComponent(novelSlug)}/chapters/${encodeURIComponent(chapterSlug)}`,
        { method: "PATCH", body, auth: true },
      );
    },
  });

  registry.add({
    path: ["chapters", "delete"],
    summary: "刪除章節（需授權；冪等）",
    usage: "fox chapters delete <novelSlug> <chapterSlug>",
    run: async (ctx) => {
      const usage = "fox chapters delete <novelSlug> <chapterSlug>";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      const chapterSlug = requirePositional(ctx.args.positionals, 1, "chapterSlug", usage);
      await call(
        ctx,
        `novels/${encodeURIComponent(novelSlug)}/chapters/${encodeURIComponent(chapterSlug)}`,
        { method: "DELETE", auth: true },
      );
    },
  });
}

export function registerGenerateCommands(registry: Registry): void {
  /** 共用：組生成請求 body 並 POST。 */
  async function postGenerate(
    ctx: CommandContext,
    novelSlug: string,
    action: "draft" | "continue" | "rewrite",
  ): Promise<void> {
    const usage = `fox generate ${action} <novelSlug> [--prompt <指示|->] [--previous-context <前文摘要|->]`;
    const body: Record<string, unknown> = {};
    const prompt = await readValue("prompt", flagString(ctx.args.flags, "prompt"));
    if (prompt !== undefined && prompt.trim()) body.prompt = prompt.trim();
    const previousContext = await readValue(
      "previous-context",
      flagString(ctx.args.flags, "previous-context"),
    );
    if (previousContext !== undefined && previousContext.trim()) {
      body.previousContext = previousContext.trim();
    }
    if (action === "draft" && body.prompt === undefined) {
      throw new UsageError(`缺少 --prompt <指示>；用法：${usage}`);
    }
    if (action === "continue" && body.previousContext === undefined) {
      throw new UsageError(`續寫需提供前文摘要；用法：${usage}`);
    }
    await call(ctx, `novels/${encodeURIComponent(novelSlug)}/generate${action === "draft" ? "" : `/${action}`}`, {
      method: "POST",
      body,
      auth: true,
    });
  }

  registry.add({
    path: ["generate", "draft"],
    summary: "草稿生成（需授權；token 需 generate scope）",
    usage: "fox generate draft <novelSlug> --prompt <指示|-> [--previous-context <前文摘要|->]",
    run: async (ctx) => {
      const usage =
        "fox generate draft <novelSlug> --prompt <指示|-> [--previous-context <前文摘要|->]";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      await postGenerate(ctx, novelSlug, "draft");
    },
  });

  registry.add({
    path: ["generate", "continue"],
    summary: "續寫（需授權；--previous-context 必填）",
    usage: "fox generate continue <novelSlug> --previous-context <前文摘要|-> [--prompt <指示|->]",
    run: async (ctx) => {
      const usage =
        "fox generate continue <novelSlug> --previous-context <前文摘要|-> [--prompt <指示|->]";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      await postGenerate(ctx, novelSlug, "continue");
    },
  });

  registry.add({
    path: ["generate", "rewrite"],
    summary: "改寫（需授權；原文放在 --prompt）",
    usage: "fox generate rewrite <novelSlug> --prompt <原文|-> [--previous-context <前文摘要|->]",
    run: async (ctx) => {
      const usage =
        "fox generate rewrite <novelSlug> --prompt <原文|-> [--previous-context <前文摘要|->]";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      await postGenerate(ctx, novelSlug, "rewrite");
    },
  });

  registry.add({
    path: ["generate", "usages"],
    summary: "查詢生成用量記帳（需授權；作者／admin）",
    usage: "fox generate usages <novelSlug>",
    run: async (ctx) => {
      const usage = "fox generate usages <novelSlug>";
      const novelSlug = requirePositional(ctx.args.positionals, 0, "novelSlug", usage);
      await call(ctx, `novels/${encodeURIComponent(novelSlug)}/generate/usages`, {
        auth: true,
      });
    },
  });
}

/** 共用型別：命令實作可引用的介面（保持單一來源）。 */
export type { Command };