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

import {
  appendNote,
  buildBackToPendingNote,
  formatNotesForDisplay,
  parseStoredNotes,
  type NoteEntry,
} from "./note-feed";

const entry = (over: Partial<NoteEntry> = {}): NoteEntry => ({
  ts: "2026-10-01T09:00:00.000Z",
  actorId: "u1",
  actorName: "Dana",
  category: "note",
  body: "something",
  ...over,
});

describe("parseStoredNotes", () => {
  it("returns an empty feed for empty / null / undefined input", () => {
    expect(parseStoredNotes("")).toEqual([]);
    expect(parseStoredNotes("   ")).toEqual([]);
    expect(parseStoredNotes(null)).toEqual([]);
    expect(parseStoredNotes(undefined)).toEqual([]);
  });

  it("returns an empty feed for legacy plain text instead of throwing", () => {
    // The old assign route wrote a bare string. Parsing must degrade.
    expect(parseStoredNotes("spoke to David")).toEqual([]);
  });

  it("returns an empty feed for a JSON object", () => {
    expect(parseStoredNotes('{"body":"x"}')).toEqual([]);
  });

  it("drops malformed entries but keeps the good ones", () => {
    const stored = JSON.stringify([entry(), { ts: "nope" }, null, "junk"]);
    const parsed = parseStoredNotes(stored);
    expect(parsed).toHaveLength(1);
    expect(parsed[0].actorName).toBe("Dana");
  });

  it("drops an entry whose category is unknown", () => {
    // Unknown category => the next read would silently lose the entry.
    const stored = JSON.stringify([entry({ category: "not-a-category" as never })]);
    expect(parseStoredNotes(stored)).toEqual([]);
  });

  it("keeps the new pending category", () => {
    const stored = JSON.stringify([entry({ category: "pending" })]);
    expect(parseStoredNotes(stored)).toHaveLength(1);
  });
});

describe("appendNote", () => {
  it("appends after the existing entries, preserving them", () => {
    const first = appendNote("", { ts: "2026-10-01T09:00:00.000Z", actor: { id: "u1", name: "Dana" }, category: "note", body: "first" });
    const second = appendNote(first, { ts: "2026-10-02T09:00:00.000Z", actor: { id: "u2", name: "Ruan" }, category: "pending", body: "second" });

    const parsed = parseStoredNotes(second);
    expect(parsed).toHaveLength(2);
    expect(parsed[0].body).toBe("first");
    expect(parsed[1].body).toBe("second");
    expect(parsed[1].actorName).toBe("Ruan");
  });

  it("does not mutate or alias the caller's string", () => {
    const before = appendNote("", { ts: "2026-10-01T09:00:00.000Z", actor: { id: "u1", name: "Dana" }, category: "note", body: "first" });
    const after = appendNote(before, { ts: "2026-10-02T09:00:00.000Z", actor: { id: "u1", name: "Dana" }, category: "note", body: "second" });

    expect(parseStoredNotes(before)).toHaveLength(1);
    expect(parseStoredNotes(after)).toHaveLength(2);
  });
});

describe("buildBackToPendingNote", () => {
  // A pre-existing entry, so the tests prove the new one is APPENDED
  // rather than written in place of the history.
  const seed = JSON.stringify([
    { ts: "2026-09-01T09:00:00.000Z", actorId: "u0", actorName: "Dana", category: "collection", body: "Collected" },
  ]);
  const last = (value: string) => {
    const entries = parseStoredNotes(value);
    return entries[entries.length - 1];
  };

  it("appends after the existing feed instead of replacing it", () => {
    const out = buildBackToPendingNote({
      currentNotes: seed,
      note: "supplier pushed it a week",
      actor: { id: "u1", name: "Dana" },
      unassigned: true,
      unready: true,
      timestamp: "2026-10-15T08:00:00.000Z",
    });
    const entries = parseStoredNotes(out);
    expect(entries).toHaveLength(2);
    expect(entries[0].body).toBe("Collected");
    expect(last(out).category).toBe("pending");
    expect(last(out).ts).toBe("2026-10-15T08:00:00.000Z");
    expect(last(out).actorName).toBe("Dana");
  });

  it("names both things it cleared", () => {
    const out = buildBackToPendingNote({
      currentNotes: "",
      note: "supplier pushed it a week",
      actor: { id: "u1", name: "Dana" },
      unassigned: true,
      unready: true,
      timestamp: "2026-10-15T08:00:00.000Z",
    });
    expect(last(out).body).toContain("driver unassigned");
    expect(last(out).body).toContain("no longer ready for collection");
    expect(last(out).body).toContain("supplier pushed it a week");
  });

  it("only claims what actually changed", () => {
    const out = buildBackToPendingNote({
      currentNotes: "",
      note: "was never assigned",
      actor: { id: "u1", name: "Dana" },
      unassigned: false,
      unready: true,
      timestamp: "2026-10-15T08:00:00.000Z",
    });
    expect(last(out).body).not.toContain("driver unassigned");
    expect(last(out).body).toContain("no longer ready");
  });

  it("still writes an entry when there was nothing to clear", () => {
    const out = buildBackToPendingNote({
      currentNotes: "",
      note: "operator nudged it",
      actor: { id: "u1", name: "Dana" },
      unassigned: false,
      unready: false,
      timestamp: "2026-10-15T08:00:00.000Z",
    });
    expect(last(out).body).toContain("no state change needed");
    expect(last(out).body).toContain("operator nudged it");
  });

  it("starts a fresh feed from a legacy plain-string value", () => {
    const out = buildBackToPendingNote({
      currentNotes: "spoke to David",
      note: "pushed back",
      actor: { id: "u1", name: "Dana" },
      unassigned: false,
      unready: true,
      timestamp: "2026-10-15T08:00:00.000Z",
    });
    const entries = parseStoredNotes(out);
    expect(entries).toHaveLength(1);
    expect(entries[0].category).toBe("pending");
    expect(entries[0].body).toContain("pushed back");
  });
});

describe("formatNotesForDisplay", () => {
  it("renders the feed as readable lines, newest first", () => {
    const stored = appendNote("", {
      ts: "2026-09-01T09:00:00.000Z",
      actor: { id: "u1", name: "Dana" },
      category: "collection",
      body: "Collected",
    });
    const withSecond = appendNote(stored, {
      ts: "2026-10-15T21:17:58.000Z",
      actor: { id: "operator", name: "Operator" },
      category: "status",
      body: "Set the expected-ready date to 21 Oct 2026",
    });

    const lines = formatNotesForDisplay(withSecond);
    expect(lines).toHaveLength(2);
    // Newest first.
    expect(lines[0]).toContain("Operator");
    expect(lines[0]).toContain("Set the expected-ready date to 21 Oct 2026");
    expect(lines[1]).toContain("Dana");
    expect(lines[1]).toContain("Collected");
  });

  it("never leaks raw JSON to the operator", () => {
    const stored = JSON.stringify([
      { ts: "2026-10-15T21:17:58.000Z", actorId: "operator", actorName: "Operator", category: "status", body: "Marked ready" },
    ]);
    const [line] = formatNotesForDisplay(stored);
    expect(line).not.toContain('"ts"');
    expect(line).not.toContain("actorId");
    expect(line).not.toContain("{");
  });

  it("flattens a multi-line note so each entry stays one line", () => {
    const stored = JSON.stringify([
      {
        ts: "2026-10-15T21:17:58.000Z",
        actorId: "operator",
        actorName: "Operator",
        category: "status",
        body: "Set the date — Delivery Date:\n1 for est. delivery\n2",
      },
    ]);
    const lines = formatNotesForDisplay(stored);
    expect(lines).toHaveLength(1);
    expect(lines[0]).not.toContain("\n");
  });

  it("renders a non-string body object without crashing", () => {
    const stored = JSON.stringify([
      {
        ts: "2026-10-15T21:17:58.000Z",
        actorId: "u1",
        actorName: "Dana",
        category: "cost",
        body: { prevCost: 100, newCost: 120 },
      },
    ]);
    const [line] = formatNotesForDisplay(stored);
    expect(line).toContain("120");
  });

  it("falls back to the raw string for a legacy plain-text value", () => {
    expect(formatNotesForDisplay("spoke to David")).toEqual(["spoke to David"]);
  });

  it("returns nothing for empty / missing input", () => {
    expect(formatNotesForDisplay("")).toEqual([]);
    expect(formatNotesForDisplay(null)).toEqual([]);
    expect(formatNotesForDisplay(undefined)).toEqual([]);
  });
});