/**
 * KHAELOR
 * File: tests/tui/fuzzy.test.ts
 * Description: Fuzzy matcher tests — subsequence matching, ranking bonuses, stability, matched indices.
 *
 * Author: Simon-Pierre Boucher
 * Contact: contact@spboucher.ai
 */

import { describe, expect, it } from "vitest";
import { fuzzyFilter, fuzzyMatch } from "../../src/tui/composer/fuzzy.js";

describe("fuzzyMatch", () => {
  it("matches subsequences case-insensitively", () => {
    expect(fuzzyMatch("agt", "src/kernel/Agent.ts")).not.toBeNull();
    expect(fuzzyMatch("zzz", "src/kernel/agent.ts")).toBeNull();
  });

  it("returns matched indices for underlining", () => {
    const m = fuzzyMatch("se", "sessions");
    expect(m?.indices).toEqual([0, 1]);
  });

  it("empty query matches everything with score 0", () => {
    expect(fuzzyMatch("", "anything")).toEqual({ score: 0, indices: [] });
  });

  it("exact prefix outranks a scattered match", () => {
    const prefix = fuzzyMatch("diff", "diff viewer") as { score: number };
    const scattered = fuzzyMatch("diff", "docs/if_frame.ts") as { score: number };
    expect(prefix.score).toBeGreaterThan(scattered.score);
  });

  it("boundary matches outrank mid-word matches", () => {
    const boundary = fuzzyMatch("ag", "src/agent.ts") as { score: number };
    const midWord = fuzzyMatch("ag", "src/flagpole.ts") as { score: number };
    expect(boundary.score).toBeGreaterThan(midWord.score);
  });
});

describe("fuzzyFilter", () => {
  const items = ["src/kernel/agent.ts", "src/agents/agent-runtime.ts", "tests/agent.test.ts"];

  it("excludes non-matches and ranks by score", () => {
    const ranked = fuzzyFilter("agent", items, (s) => s);
    expect(ranked.length).toBe(3);
    expect(ranked.every((r) => r.score > 0)).toBe(true);
  });

  it("shorter target wins ties (length penalty)", () => {
    const ranked = fuzzyFilter("cost", ["/cost-explorer", "/cost"], (s) => s);
    expect(ranked[0]?.item).toBe("/cost");
  });

  it("keeps provider order for equal scores (stable)", () => {
    const ranked = fuzzyFilter("", items, (s) => s);
    expect(ranked.map((r) => r.item)).toEqual(items);
  });

  it("filters slash commands by fragment", () => {
    const cmds = ["/sessions", "/new", "/resume", "/cost"];
    const ranked = fuzzyFilter("se", cmds, (s) => s);
    expect(ranked.map((r) => r.item)).toContain("/sessions");
    expect(ranked.map((r) => r.item)).not.toContain("/cost");
  });
});