import { describe, expect, test } from "bun:test";
import {
  mergeEvents,
  titleExtends,
  titleSimilarity,
} from "../src/ingest/merge.ts";
import { recordedSame } from "../src/ingest/aliases.ts";
import type { GachaEvent } from "../src/shared/schema.ts";

const NOW = "2026-08-14T00:00:00.000Z";

function event(overrides: Partial<GachaEvent> = {}): GachaEvent {
  return {
    id: "genshin:test-event:2026-08-12",
    game: "genshin",
    title: "Test Event",
    type: "other",
    summary: null,
    startsAt: "2026-08-12T00:00:00.000Z",
    startPrecision: "day",
    endsAt: "2026-08-24T00:00:00.000Z",
    endPrecision: "day",
    regionScoped: false,
    regionEnds: null,
    sourceUrl: "https://example.test/a",
    sourceId: "source-a",
    status: "published",
    confidence: 0.9,
    extractionMethod: "parser",
    version: 1,
    firstSeenAt: NOW,
    updatedAt: NOW,
    ...overrides,
  };
}

describe("mergeEvents", () => {
  test("keeps distinct events from different sources", () => {
    const a = event({ id: "genshin:a:2026-08-12", title: "Alpha" });
    const b = event({
      id: "genshin:b:2026-09-01",
      title: "Beta",
      startsAt: "2026-09-01T00:00:00.000Z",
      endsAt: "2026-09-10T00:00:00.000Z",
      sourceId: "source-b",
    });
    const { events, conflicts } = mergeEvents([[a], [b]]);
    expect(events).toHaveLength(2);
    expect(conflicts).toHaveLength(0);
  });

  test("collapses the same event seen by two sources", () => {
    const a = event({ sourceId: "source-a", confidence: 0.85 });
    const b = event({ sourceId: "source-b", confidence: 0.9 });
    const { events } = mergeEvents([[a], [b]]);
    expect(events).toHaveLength(1);
  });

  test("raises confidence when an independent source corroborates", () => {
    const a = event({ sourceId: "source-a", confidence: 0.85 });
    const b = event({ sourceId: "source-b", confidence: 0.85 });
    const { events } = mergeEvents([[a], [b]]);
    // Two sources independently agreeing is stronger evidence than one.
    expect(events[0]?.confidence).toBeCloseTo(0.95, 5);
  });

  test("does not corroborate a duplicate from the same source", () => {
    const a = event({ sourceId: "source-a", confidence: 0.85 });
    const { events } = mergeEvents([[a, { ...a }]]);
    expect(events).toHaveLength(1);
    expect(events[0]?.confidence).toBeCloseTo(0.85, 5);
  });

  test("matches the same event under slightly different titles", () => {
    const a = event({ title: "Stygian Onslaught", sourceId: "source-a" });
    const b = event({
      id: "genshin:stygian-onslaught-event:2026-08-12",
      title: "Stygian Onslaught Event",
      sourceId: "source-b",
    });
    const { events } = mergeEvents([[a], [b]]);
    expect(events).toHaveLength(1);
  });

  test("flags an end-date disagreement instead of picking silently", () => {
    const a = event({ sourceId: "source-a", confidence: 0.9 });
    const b = event({
      sourceId: "source-b",
      confidence: 0.8,
      endsAt: "2026-08-28T00:00:00.000Z", // 4 days later
    });
    const { events, conflicts } = mergeEvents([[a], [b]]);
    expect(events).toHaveLength(1);
    expect(conflicts).toHaveLength(1);
    expect(conflicts[0]?.field).toBe("endsAt");
    expect(conflicts[0]?.deltaHours).toBe(96);
    // The conflict is surfaced, not averaged away, and confidence is NOT
    // bumped — disagreement is the opposite of corroboration.
    expect(events[0]?.confidence).toBeCloseTo(0.9, 5);
  });

  test("treats a same-name rerun months later as a separate event", () => {
    const a = event({ title: "Windblume Festival" });
    const b = event({
      id: "genshin:windblume-festival:2027-03-01",
      title: "Windblume Festival",
      startsAt: "2027-03-01T00:00:00.000Z",
      endsAt: "2027-03-20T00:00:00.000Z",
      sourceId: "source-b",
    });
    const { events } = mergeEvents([[a], [b]]);
    expect(events).toHaveLength(2);
  });

  test("returns events sorted by start date", () => {
    const late = event({
      id: "genshin:late:2026-09-01",
      title: "Late",
      startsAt: "2026-09-01T00:00:00.000Z",
      endsAt: "2026-09-05T00:00:00.000Z",
    });
    const early = event({ id: "genshin:early:2026-08-01", title: "Early",
      startsAt: "2026-08-01T00:00:00.000Z" });
    const { events } = mergeEvents([[late], [early]]);
    expect(events.map((e) => e.title)).toEqual(["Early", "Late"]);
  });
});

describe("titleSimilarity", () => {
  test("identical titles score 1", () => {
    expect(titleSimilarity("Stygian Onslaught", "Stygian Onslaught")).toBe(1);
  });

  test("ignores case and punctuation", () => {
    expect(titleSimilarity("Gold Clash!", "gold clash")).toBe(1);
  });

  test("unrelated titles score low", () => {
    expect(titleSimilarity("Gold Clash", "Fishing Frenzy")).toBeLessThan(0.3);
  });
});

describe("titleExtends", () => {
  test("matches a title with an appended qualifier", () => {
    // Real case: Game8 says "Bedazzling Dawnstar Sign-In", wiki.gg says
    // "Bedazzling Dawnstar". Token overlap scores 0.67 — under any safe
    // threshold — but it is plainly one event.
    expect(titleExtends("Bedazzling Dawnstar", "Bedazzling Dawnstar Sign-In")).toBe(true);
  });

  test("refuses a single shared word", () => {
    // A one-word title would otherwise swallow everything containing it.
    expect(titleExtends("Rerun", "Overflowing Abundance Rerun")).toBe(false);
  });

  test("refuses a shared-word subset that is not a prefix", () => {
    // Subset matching would fuse these; they are different events.
    expect(titleExtends("Gold Clash", "Gold Rush Clash Royale")).toBe(false);
  });

  test("refuses two titles of equal length", () => {
    expect(titleExtends("Gold Clash", "Gold Rush")).toBe(false);
  });

  test("matches a title with a category label in front", () => {
    // Game8 heads Genshin's pass `Battle Pass - Moontrace` where Fandom says
    // `Moontrace`: the same qualifier, written at the other end.
    expect(titleExtends("Frozen Wilds", "Battle Pass - Frozen Wilds")).toBe(true);
  });

  test("refuses a one-word title under a label, as at the end", () => {
    // The floor holds in both directions. `Moontrace` itself is made one ID by
    // the Game8 parser dropping the label, not by loosening this.
    expect(titleExtends("Moontrace", "Battle Pass - Moontrace")).toBe(false);
  });

  test("refuses shared words in the middle", () => {
    expect(titleExtends("Gold Clash", "Royal Gold Clash Rush")).toBe(false);
  });
});

describe("merging two sources for one game", () => {
  test("collapses an appended-qualifier duplicate and flags the date gap", () => {
    const g8 = event({
      id: "endfield:bedazzling-dawnstar-sign-in:2026-08-09",
      game: "endfield",
      title: "Bedazzling Dawnstar Sign-In",
      startsAt: "2026-08-09T00:00:00.000Z",
      endsAt: "2026-08-30T00:00:00.000Z",
      sourceId: "endfield-game8-events",
      confidence: 0.85,
    });
    const wiki = event({
      id: "endfield:bedazzling-dawnstar:2026-08-09",
      game: "endfield",
      title: "Bedazzling Dawnstar",
      startsAt: "2026-08-09T04:00:00.000Z",
      endsAt: "2026-09-01T22:00:00.000Z",
      sourceId: "endfield-wikigg-events",
      confidence: 0.95,
    });
    const { events, conflicts } = mergeEvents([[g8], [wiki]]);
    expect(events).toHaveLength(1);
    // The better-sourced copy wins, and the disagreement is surfaced rather
    // than averaged into a date neither source states.
    expect(events[0]?.sourceId).toBe("endfield-wikigg-events");
    expect(conflicts).toHaveLength(1);
    expect(conflicts[0]?.field).toBe("endsAt");
  });

  test("fuses a pair when one summary names the other's title", () => {
    // Game8 and Fandom name Genshin's anniversary selectors with no word in
    // common, and Game8's own blurb names the Fandom event. That is the page
    // saying they are one, which is what a person read to establish it.
    const g8 = event({
      id: "genshin:free-limited-5-star-anniversary-selector:2026-09-23",
      title: "Free Limited 5-Star Anniversary Selector",
      summary:
        "Choose a 5-Star event-exclusive character for free in the new, annual, limited 5-star selector, Tabletop Troupe: A Gathering on Adventure's Eve!",
      startsAt: "2026-09-23T00:00:00.000Z",
      endsAt: "2026-11-03T00:00:00.000Z",
      sourceId: "genshin-game8-events",
      confidence: 0.85,
    });
    const fandom = event({
      id: "genshin:tabletop-troupe-a-gathering-on-adventures-eve:2026-09-23",
      title: "Tabletop Troupe: A Gathering on Adventure's Eve",
      startsAt: "2026-09-23T00:00:00.000Z",
      endsAt: "2026-11-03T00:00:00.000Z",
      sourceId: "genshin-fandom-events",
      confidence: 0.85,
    });
    const fused = mergeEvents([[g8], [fandom]]);
    expect(fused.events.map((e) => e.id)).toEqual([g8.id]);
    expect(fused.events[0]?.confidence).toBeCloseTo(0.95, 5);

    // Same blurb, but the named event runs a different window: a summary may
    // mention another event ("complete X to unlock this"), so both boundaries
    // must agree before a mention counts.
    const laterEnd = { ...fandom, endsAt: "2026-10-20T00:00:00.000Z" };
    expect(mergeEvents([[g8], [laterEnd]]).events).toHaveLength(2);

    // A summary that names nothing of the other's title is not evidence.
    const standardFandom = {
      ...fandom,
      id: "genshin:across-the-frozen-wilds-honing-ones-edge:2026-09-23",
      title: "Across the Frozen Wilds, Honing One's Edge",
    };
    expect(mergeEvents([[g8], [standardFandom]]).events).toHaveLength(2);
  });

  test("a blurb naming a parent event does not fuse the sub-event into it", () => {
    // Both sources list the festival and its shop over one window, and Game8's
    // shop blurb names the festival. The shop already has its own twin on
    // Fandom, so the mention is about another event, not about itself.
    const window = { startsAt: "2026-09-23T00:00:00.000Z", endsAt: "2026-11-03T00:00:00.000Z" };
    const g8Shop = event({
      ...window,
      id: "genshin:festival-shop:2026-09-23",
      title: "Festival Shop",
      summary: "Spend tokens from Starlit Gala Festival in the Festival Shop.",
      sourceId: "genshin-game8-events",
    });
    const fandomFestival = event({
      ...window,
      id: "genshin:starlit-gala-festival:2026-09-23",
      title: "Starlit Gala Festival",
      sourceId: "genshin-fandom-events",
    });
    const fandomShop = event({
      ...window,
      id: "genshin:festival-shop:2026-09-23",
      title: "Festival Shop",
      sourceId: "genshin-fandom-events",
    });
    const { events } = mergeEvents([[g8Shop], [fandomFestival, fandomShop]]);
    expect(events.map((e) => e.id).sort()).toEqual(
      [fandomFestival.id, g8Shop.id].sort(),
    );
  });

  test("a one-word title in a summary is not a mention", () => {
    const g8 = event({
      id: "genshin:free-selector:2026-09-23",
      title: "Free Selector",
      summary: "Pick a character before Moontrace ends.",
      sourceId: "genshin-game8-events",
    });
    const fandom = event({
      id: "genshin:moontrace:2026-08-12",
      title: "Moontrace",
      sourceId: "genshin-fandom-events",
    });
    expect(mergeEvents([[g8], [fandom]]).events).toHaveLength(2);
  });

  test("the survivor lists every id it absorbed", () => {
    const a = event({ id: "genshin:stygian-onslaught:2026-08-12", title: "Stygian Onslaught", sourceId: "s-a" });
    const b = event({ id: "genshin:stygian-onslaught-event:2026-08-12", title: "Stygian Onslaught Event", sourceId: "s-b" });
    const c = event({ id: "genshin:stygian-onslaught-trial:2026-08-12", title: "Stygian Onslaught Trial", sourceId: "s-c" });
    const { events } = mergeEvents([[a], [b], [c]]);
    expect(events).toHaveLength(1);
    expect(events[0]?.mergedIds).toEqual([b.id, c.id]);
  });

  test("a higher-confidence newcomer inherits what the old copy absorbed", () => {
    const a = event({ id: "genshin:x-y:2026-08-12", title: "X Y", sourceId: "s-a", confidence: 0.8 });
    const b = event({ id: "genshin:x-y-z:2026-08-12", title: "X Y Z", sourceId: "s-b", confidence: 0.8 });
    const c = event({ id: "genshin:x-y-w:2026-08-12", title: "X Y W", sourceId: "s-c", confidence: 0.95 });
    const { events } = mergeEvents([[a], [b], [c]]);
    expect(events.map((e) => e.id)).toEqual([c.id]);
    expect([...(events[0]?.mergedIds ?? [])].sort()).toEqual([a.id, b.id].sort());
  });

  test("a recorded pair matches in either order, and only itself", () => {
    const table = [{ ids: ["g:a:2026-01-01", "g:b:2026-01-01"] as const, evidence: "test" }];
    expect(recordedSame("g:b:2026-01-01", "g:a:2026-01-01", table)).toBe(true);
    expect(recordedSame("g:a:2026-01-01", "g:c:2026-01-01", table)).toBe(false);
  });

  test("an id seen twice is not an absorbed id", () => {
    const a = event({ sourceId: "s-a" });
    const { events } = mergeEvents([[a], [{ ...a, sourceId: "s-b" }]]);
    expect(events[0]?.mergedIds).toBeUndefined();
  });

  test("collapses a leading-label duplicate and keeps the first copy's id", () => {
    const g8 = event({
      id: "genshin:battle-pass-frozen-wilds:2026-09-23",
      title: "Battle Pass - Frozen Wilds",
      startsAt: "2026-09-23T00:00:00.000Z",
      endsAt: "2026-11-02T00:00:00.000Z",
      sourceId: "genshin-game8-events",
      confidence: 0.85,
    });
    const fandom = event({
      id: "genshin:frozen-wilds:2026-09-23",
      title: "Frozen Wilds",
      startsAt: "2026-09-23T00:00:00.000Z",
      endsAt: "2026-11-02T00:00:00.000Z",
      sourceId: "genshin-fandom-events",
      confidence: 0.85,
    });
    const { events, conflicts } = mergeEvents([[g8], [fandom]]);
    expect(events).toHaveLength(1);
    expect(events[0]?.id).toBe(g8.id);
    expect(conflicts).toHaveLength(0);
  });
});

describe("near matches within one source", () => {
  test("two rows from one page stay two events", () => {
    // The page has already told us these are two things, and the parser has
    // already dropped repeats of the same id — so fusing them here overrules a
    // distinction the publisher made on purpose. Game8's Umamusume banner list
    // is the real case: two concurrent banners whose titles differ by one
    // parenthetical and which start on the same day. Fusing them dropped a live
    // banner off the calendar with nothing reporting it.
    const character = event({
      id: "uma:3-star-guaranteed-1-5-anniversary-scout-character:2026-07-22",
      game: "uma",
      title: "3 Star Guaranteed 1.5 Anniversary Scout (Character)",
      sourceId: "uma-game8-events",
    });
    const support = event({
      id: "uma:3-star-guaranteed-1-5-anniversary-scout-support:2026-07-22",
      game: "uma",
      title: "3 Star Guaranteed 1.5 Anniversary Scout (Support)",
      sourceId: "uma-game8-events",
    });

    const merged = mergeEvents([[character, support]]);
    expect(merged.events).toHaveLength(2);
    expect(merged.conflicts).toHaveLength(0);
  });

  test("the same id twice from one source is still one event", () => {
    // The exception that keeps the rule safe: an identical id is the same row
    // seen twice, whatever it is called.
    const once = event({ sourceId: "source-a" });
    const twice = event({ sourceId: "source-a", title: "Test Event (again)" });
    expect(mergeEvents([[once, twice]]).events).toHaveLength(1);
  });

  test("near matches across two sources still fuse", () => {
    // The behaviour this rule narrows, not removes: reconciling two sources
    // that describe one event under different titles is the whole job.
    const a = event({ title: "Bedazzling Dawnstar", sourceId: "source-a" });
    const b = event({
      id: "genshin:bedazzling-dawnstar-sign-in:2026-08-12",
      title: "Bedazzling Dawnstar Sign-In",
      sourceId: "source-b",
    });
    expect(mergeEvents([[a], [b]]).events).toHaveLength(1);
  });
});