// IMP-56 (#90) u18 — vitest coverage for the vite POST /api/connect
// middleware and its supporting mirrorDirRecursive helper.
//
// Scope:
//   1) mirrorDirRecursive (pure helper):
//      - absent src → returns 0 (no-throw, no dst creation).
//      - file-only src → flat copy + count.
//      - nested src → recursive copy + count.
//      - overwrites pre-existing dst files (cel mirror semantics).
//   2) handleConnectMirror (POST):
//      - method != POST → false (chain continues; next middleware may handle).
//      - invalid JSON / non-object body → 400.
//      - missing run_id or slug → 400.
//      - invalid run_id or slug (key gate / path traversal) → 400.
//      - final.html missing → 404.
//      - success without run-assets dir → 200, assets_copied: 0, html copy ok.
//      - success with run-assets dir → 200, assets_copied = file count, dst dir
//        populated.
//      - dstSlidesDir auto-created when celRoot/public/slides missing.
//
// Tests exercise the pure handler with mock req/res — no real vite server.

import { describe, it, expect, beforeEach, afterEach } from "vitest";
import { EventEmitter } from "node:events";
import * as fs from "node:fs";
import * as os from "node:os";
import * as path from "node:path";
import {
  handleConnectMirror,
  mirrorDirRecursive,
} from "../../vite.config";

function makeMockRes() {
  const state = {
    statusCode: 0,
    headers: {} as Record<string, string>,
    body: "",
    ended: false,
  };
  return {
    state,
    res: {
      writeHead(status: number, headers?: Record<string, string>) {
        state.statusCode = status;
        if (headers) state.headers = headers;
      },
      end(body?: string) {
        state.body = body ?? "";
        state.ended = true;
      },
    },
  };
}

function makeMockReq(opts: {
  method?: string;
}): EventEmitter & { method?: string; send: (body: string) => void } {
  const ee = new EventEmitter() as EventEmitter & {
    method?: string;
    send: (body: string) => void;
  };
  ee.method = opts.method;
  ee.send = (body: string) => {
    if (body.length > 0) ee.emit("data", Buffer.from(body, "utf-8"));
    ee.emit("end");
  };
  return ee;
}

function seedRun(daRoot: string, runId: string, htmlBody: string): string {
  const runDir = path.join(daRoot, "data", "runs", runId, "phase_z2");
  fs.mkdirSync(runDir, { recursive: true });
  const html = path.join(runDir, "final.html");
  fs.writeFileSync(html, htmlBody, "utf-8");
  return runDir;
}

describe("mirrorDirRecursive (IMP-56 #90 u18)", () => {
  let tmp: string;

  beforeEach(() => {
    tmp = fs.mkdtempSync(path.join(os.tmpdir(), "imp90-u18-mirror-"));
  });

  afterEach(() => {
    fs.rmSync(tmp, { recursive: true, force: true });
  });

  it("returns 0 and does not throw when src absent", () => {
    const dst = path.join(tmp, "dst");
    const n = mirrorDirRecursive(path.join(tmp, "missing"), dst);
    expect(n).toBe(0);
    expect(fs.existsSync(dst)).toBe(false);
  });

  it("returns 0 when src exists but is a file (not a directory)", () => {
    const srcFile = path.join(tmp, "src.txt");
    fs.writeFileSync(srcFile, "x", "utf-8");
    const dst = path.join(tmp, "dst");
    const n = mirrorDirRecursive(srcFile, dst);
    expect(n).toBe(0);
    expect(fs.existsSync(dst)).toBe(false);
  });

  it("flat-copies file entries and returns the file count", () => {
    const src = path.join(tmp, "src");
    fs.mkdirSync(src);
    fs.writeFileSync(path.join(src, "a.css"), "/*a*/", "utf-8");
    fs.writeFileSync(path.join(src, "b.png"), "PNG", "utf-8");
    const dst = path.join(tmp, "dst");
    const n = mirrorDirRecursive(src, dst);
    expect(n).toBe(2);
    expect(fs.readFileSync(path.join(dst, "a.css"), "utf-8")).toBe("/*a*/");
    expect(fs.readFileSync(path.join(dst, "b.png"), "utf-8")).toBe("PNG");
  });

  it("recurses into nested directories and counts only files", () => {
    const src = path.join(tmp, "src");
    fs.mkdirSync(path.join(src, "nested", "deep"), { recursive: true });
    fs.writeFileSync(path.join(src, "root.txt"), "r", "utf-8");
    fs.writeFileSync(path.join(src, "nested", "n.txt"), "n", "utf-8");
    fs.writeFileSync(path.join(src, "nested", "deep", "d.txt"), "d", "utf-8");
    const dst = path.join(tmp, "dst");
    const n = mirrorDirRecursive(src, dst);
    expect(n).toBe(3);
    expect(fs.readFileSync(path.join(dst, "nested", "deep", "d.txt"), "utf-8"))
      .toBe("d");
  });

  it("overwrites pre-existing files in dst (cel mirror semantics)", () => {
    const src = path.join(tmp, "src");
    fs.mkdirSync(src);
    fs.writeFileSync(path.join(src, "a.css"), "NEW", "utf-8");
    const dst = path.join(tmp, "dst");
    fs.mkdirSync(dst);
    fs.writeFileSync(path.join(dst, "a.css"), "OLD", "utf-8");
    mirrorDirRecursive(src, dst);
    expect(fs.readFileSync(path.join(dst, "a.css"), "utf-8")).toBe("NEW");
  });
});

describe("handleConnectMirror (IMP-56 #90 u18)", () => {
  let daRoot: string;
  let celRoot: string;

  beforeEach(() => {
    daRoot = fs.mkdtempSync(path.join(os.tmpdir(), "imp90-u18-da-"));
    celRoot = fs.mkdtempSync(path.join(os.tmpdir(), "imp90-u18-cel-"));
  });

  afterEach(() => {
    fs.rmSync(daRoot, { recursive: true, force: true });
    fs.rmSync(celRoot, { recursive: true, force: true });
  });

  it("returns false (next chained) when method != POST", () => {
    const req = makeMockReq({ method: "GET" });
    const { res, state } = makeMockRes();
    const handled = handleConnectMirror(req, res, daRoot, celRoot);
    expect(handled).toBe(false);
    expect(state.ended).toBe(false);
  });

  it("returns 400 on invalid JSON body", () => {
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    const handled = handleConnectMirror(req, res, daRoot, celRoot);
    expect(handled).toBe(true);
    req.send("{not-json}");
    expect(state.statusCode).toBe(400);
    expect(JSON.parse(state.body).error).toBe("invalid JSON");
  });

  it("returns 400 when body is not a JSON object (array root)", () => {
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify(["not", "an", "object"]));
    expect(state.statusCode).toBe(400);
    expect(JSON.parse(state.body).error).toBe("body must be a JSON object");
  });

  it("returns 400 when run_id or slug is missing", () => {
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "abc" })); // slug missing
    expect(state.statusCode).toBe(400);
    expect(JSON.parse(state.body).error).toBe("missing run_id or slug");
  });

  it("returns 400 when run_id contains path traversal", () => {
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "../escape", slug: "03" }));
    expect(state.statusCode).toBe(400);
    expect(JSON.parse(state.body).error).toBe("invalid run_id or slug");
  });

  it("returns 400 when slug contains a forward slash", () => {
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "valid_id", slug: "03/etc" }));
    expect(state.statusCode).toBe(400);
    expect(JSON.parse(state.body).error).toBe("invalid run_id or slug");
  });

  it("returns 404 when final.html does not exist for run_id", () => {
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "ghost_run", slug: "03" }));
    expect(state.statusCode).toBe(404);
    expect(JSON.parse(state.body).error).toBe("final.html not found");
  });

  it("copies final.html to cel/public/slides/<slug>.html on success", () => {
    seedRun(daRoot, "mdx03_run", "<html>03</html>");
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "mdx03_run", slug: "03" }));

    expect(state.statusCode).toBe(200);
    const dstHtml = path.join(celRoot, "public", "slides", "03.html");
    expect(fs.existsSync(dstHtml)).toBe(true);
    expect(fs.readFileSync(dstHtml, "utf-8")).toBe("<html>03</html>");
    const body = JSON.parse(state.body);
    expect(body.success).toBe(true);
    expect(body.run_id).toBe("mdx03_run");
    expect(body.slug).toBe("03");
    expect(body.assets_copied).toBe(0);
    expect(body.html_target).toBe(dstHtml);
  });

  it("auto-creates cel/public/slides when missing", () => {
    seedRun(daRoot, "mdx04_run", "<html>04</html>");
    expect(fs.existsSync(path.join(celRoot, "public", "slides"))).toBe(false);
    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "mdx04_run", slug: "04" }));
    expect(state.statusCode).toBe(200);
    expect(fs.existsSync(path.join(celRoot, "public", "slides", "04.html"))).toBe(true);
  });

  it("mirrors assets/ recursively when present in the run dir", () => {
    const runDir = seedRun(daRoot, "mdx05_run", "<html>05</html>");
    fs.mkdirSync(path.join(runDir, "assets", "css"), { recursive: true });
    fs.writeFileSync(path.join(runDir, "assets", "main.css"), "*{}", "utf-8");
    fs.writeFileSync(path.join(runDir, "assets", "css", "extra.css"), "p{}", "utf-8");

    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "mdx05_run", slug: "05" }));

    expect(state.statusCode).toBe(200);
    expect(JSON.parse(state.body).assets_copied).toBe(2);
    expect(fs.readFileSync(path.join(celRoot, "public", "slides", "assets", "main.css"), "utf-8"))
      .toBe("*{}");
    expect(fs.readFileSync(path.join(celRoot, "public", "slides", "assets", "css", "extra.css"), "utf-8"))
      .toBe("p{}");
  });

  it("overwrites pre-existing cel slide html (re-Connect semantics)", () => {
    seedRun(daRoot, "mdx03_run", "NEW");
    const dstSlidesDir = path.join(celRoot, "public", "slides");
    fs.mkdirSync(dstSlidesDir, { recursive: true });
    fs.writeFileSync(path.join(dstSlidesDir, "03.html"), "OLD", "utf-8");

    const req = makeMockReq({ method: "POST" });
    const { res, state } = makeMockRes();
    handleConnectMirror(req, res, daRoot, celRoot);
    req.send(JSON.stringify({ run_id: "mdx03_run", slug: "03" }));

    expect(state.statusCode).toBe(200);
    expect(fs.readFileSync(path.join(dstSlidesDir, "03.html"), "utf-8")).toBe("NEW");
  });
});