import { describe, test, expect } from "bun:test";
import {
  trendingScore,
  bayesianRating,
  timeDecayFactor,
  popularScore,
  parseToolSlugRoute,
  normalizeDomain,
  slugify,
  type ToolSignals,
} from "../src/lib/ranking/score";

// ========== Trending 评分 ==========

describe("trendingScore", () => {
  const baseSignals: ToolSignals = {
    votesInWindow: 10,
    favoritesInWindow: 5,
    reviewsInWindow: 2,
    viewsInWindow: 100,
    ageHours: 24,
  };

  test("互动越多分数越高", () => {
    const more: ToolSignals = { ...baseSignals, votesInWindow: 50 };
    expect(trendingScore(more)).toBeGreaterThan(trendingScore(baseSignals));
  });

  test("无互动分数为 0（避免空榜填充）", () => {
    const empty: ToolSignals = {
      votesInWindow: 0,
      favoritesInWindow: 0,
      reviewsInWindow: 0,
      viewsInWindow: 0,
      ageHours: 100,
    };
    expect(trendingScore(empty)).toBe(0);
  });

  test("新工具衰减慢：相同互动下，新工具 > 老工具（防止老工具永久霸榜）", () => {
    const fresh = trendingScore({ ...baseSignals, ageHours: 24 });
    const old = trendingScore({ ...baseSignals, ageHours: 24 * 365 });
    expect(fresh).toBeGreaterThan(old);
  });

  test("评论权重高于投票", () => {
    const reviewHeavy = trendingScore({ ...baseSignals, reviewsInWindow: 3, votesInWindow: 0 });
    const voteHeavy = trendingScore({ ...baseSignals, reviewsInWindow: 0, votesInWindow: 3 });
    expect(reviewHeavy).toBeGreaterThan(voteHeavy);
  });
});

// ========== 贝叶斯评分 ==========

describe("bayesianRating", () => {
  test("评论极少时被先验拉低", () => {
    const oneFiveStar = bayesianRating(5, 1, 4.0);
    expect(oneFiveStar).toBeLessThan(5);
  });

  test("评论很多时接近观测均值", () => {
    const manyReviews = bayesianRating(4.8, 200, 4.0);
    expect(manyReviews).toBeGreaterThan(4.7);
    expect(manyReviews).toBeLessThanOrEqual(4.8);
  });

  test("样本相同的两工具，均值高者胜", () => {
    expect(bayesianRating(4.8, 10, 4.0)).toBeGreaterThan(bayesianRating(4.2, 10, 4.0));
  });

  test("无评论返回 0", () => {
    expect(bayesianRating(5, 0, 4)).toBe(0);
  });
});

// ========== 时间衰减 / Popular ==========

describe("timeDecayFactor", () => {
  test("未衰减为 1，随时间单调递减", () => {
    expect(timeDecayFactor(0)).toBe(1);
    expect(timeDecayFactor(100)).toBeLessThan(1);
    expect(timeDecayFactor(200)).toBeLessThan(timeDecayFactor(100));
  });

  test("半衰期处恰好为 0.5", () => {
    expect(timeDecayFactor(168, 168)).toBeCloseTo(0.5);
  });
});

describe("popularScore", () => {
  test("全量互动加权求和", () => {
    expect(popularScore(10, 10, 10, 1000)).toBe(10 * 2 + 10 * 1.5 + 10 * 3 + 1000 * 0.1);
  });
});

// ========== 复合路由解析（Alternatives / Comparison SEO） ==========

describe("parseToolSlugRoute", () => {
  test("普通工具", () => {
    expect(parseToolSlugRoute("chatgpt")).toEqual({ kind: "tool", slug: "chatgpt" });
  });

  test("alternatives 页", () => {
    expect(parseToolSlugRoute("chatgpt-alternatives")).toEqual({
      kind: "alternatives",
      base: "chatgpt",
    });
  });

  test("vs 对比页", () => {
    expect(parseToolSlugRoute("cursor-vs-windsurf")).toEqual({
      kind: "comparison",
      a: "cursor",
      b: "windsurf",
    });
  });

  test("名称中带连字符的对比页", () => {
    expect(parseToolSlugRoute("github-copilot-vs-tabnine")).toEqual({
      kind: "comparison",
      a: "github-copilot",
      b: "tabnine",
    });
  });
});

// ========== 域名归一化（重复工具检测） ==========

describe("normalizeDomain", () => {
  test("https URL 提取主机", () => {
    expect(normalizeDomain("https://chatgpt.com/")).toBe("chatgpt.com");
  });

  test("去 www", () => {
    expect(normalizeDomain("www.anthropic.com")).toBe("anthropic.com");
  });

  test("带路径与查询参数", () => {
    expect(normalizeDomain("https://openai.com/chatgpt?ref=x")).toBe("openai.com");
  });

  test("子域保留（重复检测按主机比较）", () => {
    expect(normalizeDomain("http://chat.openai.com")).toBe("chat.openai.com");
  });

  test("非法输入返回 null", () => {
    expect(normalizeDomain("")).toBeNull();
    expect(normalizeDomain("not a url")).toBeNull();
  });
});

// ========== slug 生成 ==========

describe("slugify", () => {
  test("空格转连字符 + 小写", () => {
    expect(slugify("Best AI Writing Tools")).toBe("best-ai-writing-tools");
  });

  test("去除特殊字符", () => {
    expect(slugify("DALL·E 3!")).toBe("dalle-3");
  });

  test("合并连续连字符", () => {
    expect(slugify("a  --  b")).toBe("a-b");
  });
});