import { describe, expect, it } from "vitest";
import {
  checkBudget,
  DEFAULT_PRIORITY_ORDER,
  determineMode,
  evaluateCacheVolume,
  type InflightTask,
  type ModeInput,
  priorityOf,
  sortByPriority,
  validatePriorityOrder,
} from "../src/index.ts";

const GiB = 1024 ** 3;
const base: ModeInput = {
  entity: null,
  releaseUnits: [],
  satisfiedUnits: [],
  slotSatisfied: false,
  now: "2026-09-27T00:00:00Z",
  newTitleWindowDays: 90,
};

describe("三种模式判定", () => {
  it("新作品按发行日期,不按站点上传日期", () => {
    expect(determineMode({ ...base, firstReleaseDate: "2026-08-01" })).toEqual({
      mode: "new_title",
      reason: "released_within_window",
    });
    expect(determineMode({ ...base, firstReleaseDate: "1999-03-31" }).reason).toBe("not_new_release");
    expect(determineMode(base).reason).toBe("release_date_unknown");
    expect(determineMode({ ...base, firstReleaseDate: "bad" }).reason).toBe("release_date_unknown");
    expect(determineMode({ ...base, firstReleaseDate: "2027-01-01" }).reason).toBe("not_yet_released");
  });
  it("追更补缺:覆盖未满足的单元", () => {
    const tv = { ...base, entity: { tracked: true, kind: "tv" as const } };
    expect(determineMode({ ...tv, releaseUnits: ["e1", "e2"], satisfiedUnits: ["e1"] }).mode).toBe("catch_up");
    expect(determineMode({ ...tv, releaseUnits: ["e1"], satisfiedUnits: ["e1"] }).reason).toBe("already_satisfied");
    expect(determineMode({ ...tv, releaseUnits: ["e1"], satisfiedUnits: ["e1"], upgradeCandidate: true }).mode).toBe(
      "upgrade",
    );
    expect(determineMode({ ...tv }).reason).toBe("no_units_resolved");
  });
  it("已有电影:Slot 缺口/更优版本 → 升级;只登记的作品不自动下载", () => {
    const mv = { ...base, entity: { tracked: true, kind: "movie" as const } };
    expect(determineMode(mv)).toEqual({ mode: "upgrade", reason: "slot_gap" });
    expect(determineMode({ ...mv, slotSatisfied: true }).mode).toBeNull();
    expect(determineMode({ ...mv, slotSatisfied: true, upgradeCandidate: true }).reason).toBe("better_version");
    expect(determineMode({ ...mv, entity: { tracked: false, kind: "movie" } }).reason).toBe("not_tracked");
  });
});

describe("优先级", () => {
  const items = [
    { id: "u", priorityClass: priorityOf("upgrade"), enqueuedAt: "2026-01-01T00:00:00Z" },
    { id: "n", priorityClass: priorityOf("new_title"), enqueuedAt: "2026-01-01T00:00:00Z" },
    { id: "c2", priorityClass: priorityOf("catch_up"), enqueuedAt: "2026-01-02T00:00:00Z" },
    { id: "c1", priorityClass: priorityOf("catch_up"), enqueuedAt: "2026-01-01T00:00:00Z" },
    { id: "i", priorityClass: priorityOf("upgrade", true), enqueuedAt: "2026-01-03T00:00:00Z" },
  ];
  it("默认 即时 > 追更 > 新作品 > 升级,同级先进先出", () => {
    expect(sortByPriority(items).map((x) => x.id)).toEqual(["i", "c1", "c2", "n", "u"]);
    expect(DEFAULT_PRIORITY_ORDER[0]).toBe("immediate");
  });
  it("可配置", () => {
    expect(sortByPriority(items, ["immediate", "new_title", "catch_up", "upgrade"]).map((x) => x.id)).toEqual([
      "i",
      "n",
      "c1",
      "c2",
      "u",
    ]);
  });
  it("配置必须完整", () => {
    expect(() => validatePriorityOrder(["immediate", "catch_up"])).toThrow();
    expect(() => validatePriorityOrder(["immediate", "catch_up", "catch_up", "upgrade"])).toThrow();
  });
});

describe("预算", () => {
  const budget = { maxNewTitlesPerDay: 3, maxBytesPerDay: 100 * GiB, maxConcurrent: 2 };
  it("放行", () => {
    const r = checkBudget(
      budget,
      { newTitlesToday: 2, bytesToday: 10 * GiB, activeDownloads: 1 },
      { countsAsNewTitle: true, bytes: GiB },
    );
    expect(r).toEqual({ decision: "allow", violations: [], unknown: [] });
  });
  it("超限列出全部违规,预留字节计入", () => {
    const r = checkBudget(
      budget,
      { newTitlesToday: 3, bytesToday: 60 * GiB, reservedBytesToday: 30 * GiB, activeDownloads: 2 },
      { countsAsNewTitle: true, bytes: 20 * GiB },
    );
    expect(r.decision).toBe("deny");
    expect(r.violations.map((v) => v.kind)).toEqual(["new_titles", "bytes", "concurrency"]);
    expect(r.violations[1]!.current).toBe(90 * GiB);
  });
  it("体积未知 → unknown,不放行;追更不占新作品额度", () => {
    const r = checkBudget(
      budget,
      { newTitlesToday: 3, bytesToday: 0, activeDownloads: 0 },
      { countsAsNewTitle: false },
    );
    expect(r).toEqual({ decision: "unknown", violations: [], unknown: ["bytes"] });
    expect(
      checkBudget({}, { newTitlesToday: 99, bytesToday: 0, activeDownloads: 99 }, { countsAsNewTitle: true }).decision,
    ).toBe("allow");
  });
});

describe("缓存卷硬阈值", () => {
  const cfg = { hardPct: 90, resumePct: 85 };
  const vol = (usedPct: number) => ({ volumeId: "v1", totalBytes: 1000 * GiB, usedBytes: usedPct * 10 * GiB });
  const task = (over: Partial<InflightTask>): InflightTask => ({
    taskId: "t",
    volumeId: "v1",
    sizeBytes: 50 * GiB,
    onDiskBytes: 0,
    managed: true,
    status: "downloading",
    ...over,
  });
  it("读不到磁盘状态 → 保守阻止", () => {
    const r = evaluateCacheVolume({
      volume: null,
      config: cfg,
      inflight: [],
      reservations: [],
      pausedByThreshold: false,
    });
    expect(r.decision).toBe("block");
    expect(r.reasons).toEqual(["volume_state_unknown"]);
  });
  it("配置校验", () => {
    expect(() =>
      evaluateCacheVolume({
        volume: vol(1),
        config: { hardPct: 80, resumePct: 85 },
        inflight: [],
        reservations: [],
        pausedByThreshold: false,
      }),
    ).toThrow();
  });
  it("达到硬阈值 → 暂停纳管的下载中任务", () => {
    const r = evaluateCacheVolume({
      volume: vol(91),
      config: cfg,
      inflight: [
        task({ taskId: "a" }),
        task({ taskId: "b", managed: false }),
        task({ taskId: "c", status: "paused" }),
        task({ taskId: "d", volumeId: "v2" }),
      ],
      reservations: [],
      pausedByThreshold: false,
    });
    expect(r.decision).toBe("pause_managed");
    expect(r.pauseTaskIds).toEqual(["a"]);
    expect(r.unmanagedGrowthRisk).toBe(true);
  });
  it("在途剩余需求 + 预留:已预分配不重复扣,已提交计划不重复算预留", () => {
    const r = evaluateCacheVolume({
      volume: vol(70),
      config: cfg,
      inflight: [
        task({ taskId: "a", planId: "p1", sizeBytes: 100 * GiB, onDiskBytes: 100 * GiB }),
        task({ taskId: "b", planId: "p2", sizeBytes: 100 * GiB, onDiskBytes: 40 * GiB }),
        task({ taskId: "c", status: "completed", sizeBytes: 500 * GiB }),
      ],
      reservations: [
        { planId: "p2", volumeId: "v1", bytes: 100 * GiB },
        { planId: "p3", volumeId: "v1", bytes: 50 * GiB },
        { planId: "p4", volumeId: "v2", bytes: 999 * GiB },
      ],
      request: { bytes: 60 * GiB },
      pausedByThreshold: false,
    });
    expect(r.pendingBytes).toBe(60 * GiB);
    expect(r.reservedBytes).toBe(50 * GiB);
    expect(r.projectedPct).toBeCloseTo(87);
    expect(r.decision).toBe("allow");
    const over = evaluateCacheVolume({
      volume: vol(70),
      config: cfg,
      inflight: [task({ sizeBytes: 150 * GiB })],
      reservations: [],
      request: { bytes: 60 * GiB },
      pausedByThreshold: false,
    });
    expect(over.decision).toBe("block");
    expect(over.reasons).toContain("projected_over_threshold");
  });
  it("体积未知 → 阻止新提交", () => {
    const r = evaluateCacheVolume({
      volume: vol(10),
      config: cfg,
      inflight: [task({ sizeBytes: undefined, taskId: "m" })],
      reservations: [],
      request: {},
      pausedByThreshold: false,
    });
    expect(r.decision).toBe("block");
    expect(r.reasons).toEqual(["request_size_unknown", "inflight_size_unknown"]);
    expect(r.unknownSizeTaskIds).toEqual(["m"]);
  });
  it("恢复水位滞回:85%~90% 之间保持暂停,≤85% 恢复阈值暂停的任务", () => {
    const mid = evaluateCacheVolume({
      volume: vol(87),
      config: cfg,
      inflight: [],
      reservations: [],
      pausedByThreshold: true,
    });
    expect(mid.decision).toBe("block");
    expect(mid.resumeThresholdPaused).toBe(false);
    const low = evaluateCacheVolume({
      volume: vol(80),
      config: cfg,
      inflight: [],
      reservations: [],
      pausedByThreshold: true,
    });
    expect(low.decision).toBe("allow");
    expect(low.resumeThresholdPaused).toBe(true);
    expect(low.reasons).toEqual(["below_resume_watermark"]);
  });
});