import { parseCount } from "@/lib/utils";
import { runWithConcurrency } from "@/lib/utils/concurrency";
import { rankAndDedupe, type RankedPost } from "@/lib/ranking";
import type { ScanTask } from "@/lib/services/scan-tasks";
import { withSharedContext, type BrowserSessionOptions } from "./browser";
import {
  DEFAULT_TASK_STAGGER_MS,
  getBrowserConcurrency,
  humanLandingPause,
  humanPause,
  humanScrollPage,
} from "./human-behavior";
import { browserSessionOptions, type ActiveSession } from "./session";
import { extractFromPageScripts, extractPostsFromJson } from "./extract";
import { getProfilePostsOnPage } from "./profile";
import type { BrowserCrawlStep, BrowserProgressCallback } from "./progress";
import type { ThreadsPost } from "./types";
import {
  assertThreadsPageSafe,
  consumeCrawlerPageQuota,
  limitCrawlerTasks,
} from "./safety";

const HOME_URL = "https://www.threads.com/";
const IG_APP_ID = "238260118697367";

async function scrapeFromDom(page: import("playwright").Page): Promise<ThreadsPost[]> {
  const posts: ThreadsPost[] = [];
  const seen = new Set<string>();

  const postLinks = page.locator('a[href*="/post/"]');
  const count = await postLinks.count();

  for (let i = 0; i < Math.min(count, 40); i++) {
    const link = postLinks.nth(i);
    try {
      const href = await link.getAttribute("href", { timeout: 1200 });
      if (!href || seen.has(href)) continue;
      seen.add(href);

      const permalink = href.startsWith("http") ? href : `https://www.threads.com${href}`;
      const authorName = href.match(/@([^/]+)\/post/)?.[1];

      const container = link.locator("xpath=ancestor::*[contains(@data-pressable-container,'true')][1]");
      const hasContainer = (await container.count()) > 0;
      const scope = hasContainer ? container : link.locator("xpath=ancestor::div[position()<=6]").first();

      const textEl = scope.locator('div[dir="auto"], span[dir="auto"]').first();
      const text = await textEl.innerText({ timeout: 1200 }).catch(() => "");
      if (!text || text.length < 5) continue;

      const statsText = await scope.innerText().catch(() => "");
      const likeMatch = statsText.match(/(\d[\d.,kKmM萬]*)\s*(讚|likes?)/i);
      const replyMatch = statsText.match(/(\d[\d.,kKmM萬]*)\s*(則回覆|replies?|留言)/i);

      posts.push({
        text: text.trim(),
        permalink,
        authorName,
        likeCount: parseCount(likeMatch?.[1]),
        replyCount: parseCount(replyMatch?.[1]),
        externalId: href.match(/\/post\/([^/?]+)/)?.[1],
      });
    } catch {
      // skip unreadable post
    }
  }

  return posts;
}

async function primeSession(
  page: import("playwright").Page,
  onStep?: BrowserProgressCallback
): Promise<void> {
  await onStep?.("session_check");
  const response = await page.goto(HOME_URL, { waitUntil: "domcontentloaded", timeout: 45000 });
  await onStep?.("landing_pause", "首頁");
  await humanLandingPause(page);

  const bodyText = await page.locator("body").innerText().catch(() => "");
  await assertThreadsPageSafe(page, response?.status(), bodyText);
  if (page.url().includes("/login")) {
    throw new Error("Session 已失效，請到設定頁重新登入 Threads");
  }
}

function attachGraphqlCollector(page: import("playwright").Page, collected: ThreadsPost[]) {
  page.on("response", async (response) => {
    const url = response.url();
    if (!url.includes("graphql") && !url.includes("threads") && !url.includes("instagram")) {
      return;
    }
    try {
      const contentType = response.headers()["content-type"] ?? "";
      if (!contentType.includes("json")) return;
      const json = await response.json();
      extractPostsFromJson(json, collected);
    } catch {
      // ignore parse errors
    }
  });
}

export async function searchQueryOnPage(
  page: import("playwright").Page,
  query: string,
  limit = 20,
  onStep?: BrowserProgressCallback
): Promise<RankedPost[]> {
  const collected: ThreadsPost[] = [];
  attachGraphqlCollector(page, collected);

  const searchUrl = `https://www.threads.com/search?q=${encodeURIComponent(query)}&serp_type=default`;
  await onStep?.("open_page", `搜尋「${query}」`);
  const response = await page.goto(searchUrl, { waitUntil: "domcontentloaded", timeout: 45000 });
  await onStep?.("landing_pause");
  await humanLandingPause(page);

  const bodyText = await page.locator("body").innerText();
  await assertThreadsPageSafe(page, response?.status(), bodyText);
  if (bodyText.includes("走丟") || bodyText.includes("頁面不存在")) {
    await onStep?.("done", "0 篇");
    return [];
  }

  await onStep?.("wait_content");
  await page.waitForSelector('a[href*="/post/"]', { timeout: 12000 }).catch(() => undefined);
  await onStep?.("scroll");
  await humanScrollPage(page, { minPasses: 2, maxPasses: 4 });

  if (collected.length < 3) {
    await onStep?.("parse_scripts");
    const { posts: scriptPosts } = await extractFromPageScripts(page);
    collected.push(...scriptPosts);
  } else {
    await onStep?.("parse_network", `${collected.length} 篇`);
  }

  if (collected.length < 3) {
    await onStep?.("parse_dom");
    const domPosts = await scrapeFromDom(page);
    collected.push(...domPosts);
  }

  const ranked = rankAndDedupe(collected, limit);
  await onStep?.("done", `${ranked.length} 篇`);
  return ranked;
}

function resolveSessionOptions(session?: ActiveSession): BrowserSessionOptions | undefined {
  return session ? browserSessionOptions(session) : undefined;
}

export interface BrowserSearchOptions {
  onStep?: BrowserProgressCallback;
}

export async function search(
  storageState: string,
  query: string,
  limit = 20,
  session?: ActiveSession,
  options?: BrowserSearchOptions
): Promise<RankedPost[]> {
  return withSharedContext(
    storageState,
    async (context) => {
      const page = await context.newPage();
      await primeSession(page, options?.onStep);
      return searchQueryOnPage(page, query, limit, options?.onStep);
    },
    resolveSessionOptions(session)
  );
}

export type RankedPostWithTag = RankedPost & { searchTag?: string };

function mergePosts(batches: RankedPostWithTag[][]): RankedPostWithTag[] {
  const merged = new Map<string, RankedPostWithTag>();
  for (const batch of batches) {
    for (const post of batch) {
      const key = post.externalId ?? `${post.authorName ?? ""}:${post.text.trim().slice(0, 120)}`;
      const existing = merged.get(key);
      if (!existing || post.score > existing.score) {
        merged.set(key, post);
      }
    }
  }
  return Array.from(merged.values()).sort((a, b) => b.score - a.score);
}

/** 執行混合任務：關鍵字搜尋 + 帳號海巡，有限平行（建議 ≤3） */
export async function executeScanTasks(
  storageState: string,
  tasks: ScanTask[],
  options?: {
    session?: ActiveSession;
    concurrency?: number;
    onProgress?: (done: number, total: number, label: string) => void;
    shouldAbort?: () => boolean | Promise<boolean>;
    onTaskStart?: (task: ScanTask) => void | Promise<void>;
    onTaskDone?: (task: ScanTask, found: number) => void | Promise<void>;
    onTaskFail?: (task: ScanTask, error: unknown) => void | Promise<void>;
    onTaskStep?: (
      task: ScanTask,
      step: BrowserCrawlStep,
      detail?: string
    ) => void | Promise<void>;
  }
): Promise<RankedPostWithTag[]> {
  const safeTasks = limitCrawlerTasks(tasks);
  if (safeTasks.length === 0) return [];

  try {
    return await withSharedContext(storageState, async (context) => {
      const primePage = await context.newPage();
      await primeSession(primePage, (step, detail) =>
        options?.onTaskStep?.(safeTasks[0] ?? { id: "prime", kind: "keyword", query: "", label: "初始化", limit: 0 }, step, detail)
      );
      await primePage.close();

      const results = await runWithConcurrency(
        safeTasks,
        async (task) => {
          consumeCrawlerPageQuota(options?.session?.id);
          await options?.onTaskStart?.(task);
          const page = await context.newPage();
          const onStep: BrowserProgressCallback = (step, detail) =>
            options?.onTaskStep?.(task, step, detail);
          try {
            let posts: RankedPost[];
            if (task.kind === "account") {
              posts = await getProfilePostsOnPage(page, task.query, task.limit, onStep);
            } else {
              posts = await searchQueryOnPage(page, task.query, task.limit, onStep);
            }
            const mapped = posts.map((post) => ({ ...post, searchTag: task.label }));
            await options?.onTaskDone?.(task, mapped.length);
            return mapped;
          } catch (error) {
            await options?.onTaskFail?.(task, error);
            throw error;
          } finally {
            await onStep("between_pages");
            await humanPause("betweenPages");
            await page.close();
          }
        },
        {
          concurrency: options?.concurrency ?? getBrowserConcurrency(),
          staggerMs: DEFAULT_TASK_STAGGER_MS,
          shouldAbort: options?.shouldAbort,
          onProgress: (done, total) => {
            const task = safeTasks[done - 1];
            options?.onProgress?.(done, total, task?.label ?? "");
          },
        }
      );

      return mergePosts(results);
    }, resolveSessionOptions(options?.session));
  } catch (error) {
    if (error instanceof Error && error.message === "__JOB_ABORT__") {
      const { JobCancelledError } = await import("@/lib/jobs/cancel");
      throw new JobCancelledError();
    }
    throw error;
  }
}

/** @deprecated 使用 executeScanTasks */
export async function searchTagsParallel(
  storageState: string,
  tags: string[],
  perTagLimit: number,
  options?: {
    concurrency?: number;
    onProgress?: (done: number, total: number, tag: string) => void;
  }
): Promise<RankedPostWithTag[]> {
  const tasks: ScanTask[] = tags.map((tag) => ({
    id: `keyword:${tag}`,
    kind: "keyword",
    query: tag,
    label: tag,
    limit: perTagLimit,
  }));
  return executeScanTasks(storageState, tasks, options);
}

export { IG_APP_ID };