/**
 * item-size — the size parser and the line ↔ candidate comparison.
 *
 * The descriptions in the "real descriptions" block below are the ones
 * that came off live data on 2026-10-24, where the POS shortlist
 * ranked an M22 bolt above the M16 the customer asked for because
 * they share the words "BOLT 8.8 ZP".
 */

import { describe, expect, it } from "vitest";

import {
  compareSizes,
  describeSize,
  parseItemSize,
  SIZE_RANK_EXACT,
  SIZE_RANK_KIND,
  SIZE_RANK_NEAR_BASE,
  SIZE_RANK_OTHER,
  SIZE_RANK_THREAD,
} from "./item-size";

describe("parseItemSize — the real descriptions", () => {
  it("reads a shorthand bolt", () => {
    expect(parseItemSize("BOLT HEX M16X60 GR8.8 ZP")).toEqual({
      kind: "bolt",
      variant: null,
      thread: "M16",
      length: 60,
      grade: "8.8",
      finish: "zp",
      dims: [],
    });
  });

  it("reads a spelled-out bolt", () => {
    expect(parseItemSize("Hex bolt M16 x 60 grade 8.8 zinc plated")).toEqual({
      kind: "bolt",
      variant: null,
      thread: "M16",
      length: 60,
      grade: "8.8",
      finish: "zp",
      dims: [],
    });
  });

  it("reads a bare grade and a different size", () => {
    expect(parseItemSize("M22x65 BOLT 8.8 ZP")).toEqual({
      kind: "bolt",
      variant: null,
      thread: "M22",
      length: 65,
      grade: "8.8",
      finish: "zp",
      dims: [],
    });
  });

  it("reads a nyloc nut in both word orders", () => {
    for (const text of ["NUT NYLOC M16 ZINC", "Nyloc nut M16 zinc plated"]) {
      expect(parseItemSize(text)).toEqual({
        kind: "nut",
        variant: "nyloc",
        thread: "M16",
        length: null,
        grade: null,
        finish: "zp",
        dims: [],
      });
    }
  });

  it("reads a flat washer", () => {
    expect(parseItemSize("WASHER FLAT M16 ZINC PLATED")).toEqual({
      kind: "washer",
      variant: "flat",
      thread: "M16",
      length: null,
      grade: null,
      finish: "zp",
      dims: [],
    });
  });

  it("reads a spring washer", () => {
    const s = parseItemSize("SPRING WASHER M16 ZP");
    expect(s.kind).toBe("washer");
    expect(s.variant).toBe("spring");
  });

  it("reads a funnel with two dimensions and no kind", () => {
    expect(parseItemSize('Funnel 150mm PVC round 2 piece Flexible ("6") Round')).toEqual({
      kind: null,
      variant: null,
      thread: null,
      length: null,
      grade: null,
      finish: null,
      dims: [
        { value: 150, unit: "mm" },
        { value: 6, unit: "in" },
      ],
    });
  });

  it("reads a welding rod", () => {
    expect(parseItemSize("Welding rod 2.5mm")).toEqual({
      kind: null,
      variant: null,
      thread: null,
      length: null,
      grade: null,
      finish: null,
      dims: [{ value: 2.5, unit: "mm" }],
    });
  });

  it("reads a U bolt with a bracketed length", () => {
    expect(parseItemSize("U BOLT M24(400) HDG")).toEqual({
      kind: "bolt",
      variant: null,
      thread: "M24",
      length: 400,
      grade: null,
      finish: "hdg",
      dims: [],
    });
  });
});

describe("parseItemSize — the attributes", () => {
  it("keeps the type word in either order", () => {
    expect(parseItemSize("hex bolt M16").kind).toBe("bolt");
    expect(parseItemSize("bolt hex M16").kind).toBe("bolt");
  });

  it("knows the other fastener types", () => {
    expect(parseItemSize("M6x30 SET SCR A2").kind).toBe("setscrew");
    expect(parseItemSize("M6x30 set screw A2").kind).toBe("setscrew");
    expect(parseItemSize("M8 cap screw 40").kind).toBe("cap_screw");
    expect(parseItemSize("M10 threaded stud 100").kind).toBe("stud");
    expect(parseItemSize("Chemical anchor 300").kind).toBe("anchor");
    expect(parseItemSize("4.8 rivet 16").kind).toBe("rivet");
  });

  it("leaves an unknown type alone", () => {
    expect(parseItemSize("Funnel 150mm PVC").kind).toBeNull();
    expect(parseItemSize("Welding rod 2.5mm").kind).toBeNull();
  });

  it("reads the thread from every spelling", () => {
    expect(parseItemSize("M16").thread).toBe("M16");
    expect(parseItemSize("M16X60").thread).toBe("M16");
    expect(parseItemSize("M16 x 60").thread).toBe("M16");
    expect(parseItemSize("m16x60mm").thread).toBe("M16");
    expect(parseItemSize("M 16").thread).toBe("M16");
  });

  it("reads an imperial thread", () => {
    expect(parseItemSize('1/2" bolt').thread).toBe('1/2"');
    expect(parseItemSize("1/2 UNC bolt").thread).toBe("1/2UNC");
  });

  it("reads the length that follows the thread", () => {
    expect(parseItemSize("M16x60").length).toBe(60);
    expect(parseItemSize("M16 X 60MM").length).toBe(60);
    expect(parseItemSize("M16 × 60").length).toBe(60);
    expect(parseItemSize("M16x60mm").length).toBe(60);
    expect(parseItemSize("M16").length).toBeNull();
  });

  it("reads the grade in every spelling", () => {
    expect(parseItemSize("bolt GR8.8").grade).toBe("8.8");
    expect(parseItemSize("bolt grade 8.8").grade).toBe("8.8");
    expect(parseItemSize("bolt GR 10.9").grade).toBe("10.9");
    expect(parseItemSize("bolt 12.9").grade).toBe("12.9");
    expect(parseItemSize("bolt 4.6").grade).toBe("4.6");
  });

  it("does not read a plain number as a grade", () => {
    expect(parseItemSize("bolt 60mm").grade).toBeNull();
    expect(parseItemSize("washer 150").grade).toBeNull();
  });

  it("reads the finish", () => {
    expect(parseItemSize("bolt zp").finish).toBe("zp");
    expect(parseItemSize("bolt zinc").finish).toBe("zp");
    expect(parseItemSize("bolt zinc plated").finish).toBe("zp");
    expect(parseItemSize("bolt hdg").finish).toBe("hdg");
    expect(parseItemSize("bolt galv").finish).toBe("hdg");
    expect(parseItemSize("bolt hot dip galvanised").finish).toBe("hdg");
    expect(parseItemSize("bolt ss").finish).toBe("ss");
    expect(parseItemSize("bolt stainless").finish).toBe("ss");
    expect(parseItemSize("bolt 304").finish).toBe("ss");
    expect(parseItemSize("bolt 316").finish).toBe("ss");
    expect(parseItemSize("bolt black").finish).toBe("black");
    expect(parseItemSize("bolt self colour").finish).toBe("black");
    expect(parseItemSize("bolt plain").finish).toBeNull();
  });

  it("reads a dimension with its unit", () => {
    expect(parseItemSize("pipe 150mm").dims).toEqual([{ value: 150, unit: "mm" }]);
    expect(parseItemSize("drum 20L").dims).toEqual([{ value: 20, unit: "l" }]);
    expect(parseItemSize("plate 2.5mm").dims).toEqual([{ value: 2.5, unit: "mm" }]);
    expect(parseItemSize('plate 6"').dims).toEqual([{ value: 6, unit: "in" }]);
  });

  it("does not read the thread length as a dimension", () => {
    expect(parseItemSize("M16x60mm").dims).toEqual([]);
    expect(parseItemSize("M16 X 60MM").dims).toEqual([]);
    expect(parseItemSize("U BOLT M24(400) HDG").dims).toEqual([]);
  });

  it("survives rubbish input", () => {
    expect(parseItemSize("")).toEqual({
      kind: null,
      variant: null,
      thread: null,
      length: null,
      grade: null,
      finish: null,
      dims: [],
    });
    expect(parseItemSize("the and of").kind).toBeNull();
  });
});

describe("compareSizes", () => {
  const line = parseItemSize("BOLT HEX M16X60 GR8.8 ZP");

  it("is exact when every attribute the line gives matches", () => {
    const cand = parseItemSize("HEX BOLT M16X60 8.8 ZP");
    const cmp = compareSizes(line, cand);
    expect(cmp.exact).toBe(true);
    expect(cmp.differs).toEqual([]);
    expect(cmp.rank).toBe(SIZE_RANK_EXACT);
  });

  it("spells the differences out in plain words", () => {
    const cmp = compareSizes(line, parseItemSize("M22x65 BOLT 8.8 ZP"));
    expect(cmp.exact).toBe(false);
    expect(cmp.differs).toContain("thread M22 vs M16");
    expect(cmp.differs).toContain("length 65 vs 60");
  });

  it("spells a finish difference out", () => {
    const cmp = compareSizes(line, parseItemSize("M16X60 BOLT 8.8 HDG"));
    expect(cmp.differs).toContain("finish HDG vs ZP");
  });

  it("never counts an attribute the line does not mention", () => {
    // The line says nothing about the finish — a candidate with a
    // different finish must not be marked down for it.
    const bare = parseItemSize("BOLT M16X60");
    const cmp = compareSizes(bare, parseItemSize("BOLT M16X60 HDG"));
    expect(cmp.differs).toEqual([]);
    expect(cmp.exact).toBe(true);
  });

  it("counts an attribute the candidate does not mention", () => {
    const cmp = compareSizes(line, parseItemSize("HEX BOLT M16"));
    expect(cmp.exact).toBe(false);
    expect(cmp.differs).toContain("length ? vs 60");
    expect(cmp.differs).toContain("grade ? vs 8.8");
    expect(cmp.differs).toContain("finish ? vs zp");
  });

  it("is never exact when the line says nothing about size", () => {
    const bare = parseItemSize("Widget");
    const cmp = compareSizes(bare, parseItemSize("Widget"));
    expect(cmp.exact).toBe(false);
    expect(cmp.rank).toBe(SIZE_RANK_OTHER);
  });

  it("is exact when the line only names a type and the candidate is the same type", () => {
    const cmp = compareSizes(parseItemSize("Hex bolt"), parseItemSize("HEX BOLT M16"));
    expect(cmp.exact).toBe(true);
  });

  it("ranks same kind + thread + length first", () => {
    const cmp = compareSizes(line, parseItemSize("HEX BOLT M16X60 8.8 ZP"));
    expect(cmp.rank).toBe(SIZE_RANK_EXACT);
  });

  it("ranks same kind + thread by how near the length is", () => {
    const near = compareSizes(line, parseItemSize("HEX BOLT M16X65 8.8 ZP"));
    const far = compareSizes(line, parseItemSize("HEX BOLT M16X170 8.8 ZP"));
    expect(near.rank).toBe(SIZE_RANK_NEAR_BASE + 5);
    expect(far.rank).toBe(SIZE_RANK_NEAR_BASE + 110);
    expect(near.rank).toBeLessThan(far.rank);
  });

  it("ranks the same thread above the same kind with a different thread", () => {
    const sameThread = compareSizes(line, parseItemSize("NUT M16 8.8 ZP"));
    const sameKind = compareSizes(line, parseItemSize("M22X60 BOLT 8.8 ZP"));
    expect(sameThread.rank).toBe(SIZE_RANK_THREAD);
    expect(sameKind.rank).toBe(SIZE_RANK_KIND);
    expect(sameThread.rank).toBeLessThan(sameKind.rank);
  });

  it("ranks an M16x60 bolt above an M22x65 bolt", () => {
    const right = compareSizes(line, parseItemSize("HEX BOLT M16X60 8.8 ZP"));
    const wrong = compareSizes(line, parseItemSize("HEX BOLT M22X65 8.8 ZP"));
    expect(right.rank).toBeLessThan(wrong.rank);
  });

  it("ranks everything else last", () => {
    const cmp = compareSizes(line, parseItemSize("Funnel 150mm PVC"));
    expect(cmp.rank).toBe(SIZE_RANK_OTHER);
  });

  it("compares dimensions", () => {
    const funnel = parseItemSize('Funnel 150mm PVC round 2 piece Flexible ("6") Round');
    const same = parseItemSize("Funnel 150mm PVC");
    const other = parseItemSize("Funnel 100mm PVC");
    expect(compareSizes(funnel, same).differs).toContain("size ? vs 6in");
    expect(compareSizes(funnel, other).differs).toContain("size 100mm vs 150mm");
  });
});

describe("describeSize", () => {
  it("writes one short line", () => {
    expect(describeSize(parseItemSize("BOLT HEX M16X60 GR8.8 ZP"))).toBe(
      "bolt, thread M16, length 60, grade 8.8, finish zp",
    );
  });

  it("says nothing when there is nothing to say", () => {
    expect(describeSize(parseItemSize("Widget"))).toBe("");
  });
});