import { mkdtempSync, rmSync } from "node:fs";
import { tmpdir } from "node:os";
import { join } from "node:path";
import { describe, expect, it } from "vitest";
import {
  emptyArtifact,
  serializeArtifact,
  type Artifact,
  type Proposal,
} from "../src/model";
import { CoauthorStore } from "../src/store";
import { addProposal, proposalBody, removeProposal } from "../src/proposalModel";

const agent = {
  kind: "agent" as const,
  id: "claude",
  agent: { sdk: "@cline/sdk", model: "sonnet", sessionId: "s1" },
};

describe("Proposal model (spec §6.3, INV-13)", () => {
  it("serializes proposals with stable field order and survives a round-trip", () => {
    const a = emptyArtifact("docs/x.md");
    a.anchors["a_1"] = {
      fingerprint: { text: "old text", before: "", after: "", lineHint: 0 },
    };
    const p: Proposal = {
      id: "pr_1",
      anchorId: "a_1",
      replacement: "new text",
      author: agent,
      createdAt: "2026-06-10T00:00:00.000Z",
      turnId: "turn-1",
      instruction: "tighten",
    };
    a.proposals.push(p);
    const reloaded = JSON.parse(serializeArtifact(a)) as Artifact;
    expect(reloaded.proposals).toHaveLength(1);
    expect(reloaded.proposals[0]).toEqual(p);
    // optional fields are OMITTED (not null) when absent
    const bare: Proposal = {
      id: "pr_2", anchorId: "a_1", replacement: "r", author: agent,
      createdAt: "2026-06-10T00:00:00.000Z",
    };
    a.proposals.push(bare);
    const again = JSON.parse(serializeArtifact(a)) as Artifact;
    expect("turnId" in again.proposals[1]).toBe(false);
    expect("instruction" in again.proposals[1]).toBe(false);
    // serialization is byte-stable (INV-2)
    expect(serializeArtifact(again)).toBe(serializeArtifact(a));
  });
});

describe("CoauthorStore prune with proposals (spec §6.3)", () => {
  it("retains anchors referenced only by proposals; prunes them after removal", () => {
    const dir = mkdtempSync(join(tmpdir(), "cowriting-prune-"));
    try {
      const store = new CoauthorStore(dir);
      store.update("docs/x.md", (a) => {
        a.anchors["a_p"] = {
          fingerprint: { text: "t", before: "", after: "", lineHint: 0 },
        };
        a.proposals.push({
          id: "pr_1", anchorId: "a_p", replacement: "r", author: agent,
          createdAt: "2026-06-10T00:00:00.000Z",
        });
      });
      expect(store.load("docs/x.md")!.anchors["a_p"]).toBeDefined();
      store.update("docs/x.md", (a) => {
        a.proposals = a.proposals.filter((p) => p.id !== "pr_1");
      });
      expect(store.load("docs/x.md")!.anchors["a_p"]).toBeUndefined();
    } finally {
      rmSync(dir, { recursive: true, force: true });
    }
  });
});

describe("proposalModel helpers (spec §6.4)", () => {
  const fp = { text: "old line one\nold line two", before: "", after: "", lineHint: 3 };

  it("addProposal creates the anchor + pending record; removeProposal deletes by id", () => {
    const a = emptyArtifact("docs/x.md");
    const { proposalId, anchorId } = addProposal(a, fp, "new line", agent, {
      turnId: "turn-9", instruction: "shorten",
    });
    expect(a.anchors[anchorId].fingerprint).toEqual(fp);
    expect(a.proposals).toHaveLength(1);
    expect(a.proposals[0].id).toBe(proposalId);
    expect(a.proposals[0].replacement).toBe("new line");
    expect(a.proposals[0].turnId).toBe("turn-9");
    expect(a.proposals[0].instruction).toBe("shorten");
    expect(removeProposal(a, proposalId)).toBe(true);
    expect(a.proposals).toHaveLength(0);
    expect(removeProposal(a, proposalId)).toBe(false);
  });

  it("proposalBody renders instruction + a fenced unified diff of old → new", () => {
    const a = emptyArtifact("docs/x.md");
    addProposal(a, fp, "new only line", agent, { instruction: "merge the lines" });
    const body = proposalBody(fp.text, a.proposals[0]);
    expect(body).toContain("**Claude proposes** — _merge the lines_");
    expect(body).toContain("```diff");
    expect(body).toContain("- old line one");
    expect(body).toContain("- old line two");
    expect(body).toContain("+ new only line");
  });
});