import { existsSync, readFileSync, readdirSync, statSync } from "node:fs";
import { dirname, join, relative, resolve } from "node:path";
import { describe, expect, it } from "vitest";
import { parse } from "yaml";

// F4 (D41 #4/#6) packaging contract: the editor's electron-builder config must
// stay valid, its files globs must cover the compiled entrypoints, and every
// main-process runtime import must resolve inside the production dependency
// closure (so the packaged app's auto-collected node_modules contains it).

const APP_DIR = resolve(process.cwd());
const CONFIG = readFileSync(join(APP_DIR, "electron-builder.yml"), "utf8");
const config = parse(CONFIG) as Record<string, unknown>;

const PACKAGE_JSON = JSON.parse(readFileSync(join(APP_DIR, "package.json"), "utf8")) as {
  main?: string;
  scripts?: Record<string, string>;
  dependencies?: Record<string, string>;
};

function asStringList(value: unknown): string[] {
  return Array.isArray(value) ? value.map((v) => String(v)) : [];
}

function escapeRegex(text: string): string {
  return text.replace(/[.*+?^${}()|[\]\\]/g, "\\$&");
}

/** Minimal glob matcher for electron-builder-style patterns (`**` + `*`). */
function globMatches(pattern: string, relPath: string): boolean {
  const parts = pattern.split("/");
  const pathParts = relPath.split("/");
  const queue = [{ p: 0, q: 0 }];
  const seen = new Set<string>();
  while (queue.length > 0) {
    const { p, q } = queue.pop() as { p: number; q: number };
    const key = `${p}:${q}`;
    if (seen.has(key)) continue;
    seen.add(key);
    if (p === parts.length) {
      if (q === pathParts.length) return true;
      continue;
    }
    const part = parts[p] ?? "";
    if (part === "**") {
      queue.push({ p: p + 1, q });
      if (q < pathParts.length) queue.push({ p, q: q + 1 });
      continue;
    }
    if (q >= pathParts.length) continue;
    const re = new RegExp(`^${part.split("*").map(escapeRegex).join("[^/]*")}$`);
    if (re.test(pathParts[q] ?? "")) queue.push({ p: p + 1, q: q + 1 });
  }
  return false;
}

function walkFiles(dir: string, base: string, out: string[]): string[] {
  for (const entry of readdirSync(dir)) {
    const abs = join(dir, entry);
    const rel = relative(base, abs).split("\\").join("/");
    if (statSync(abs).isDirectory()) walkFiles(abs, base, out);
    else out.push(rel);
  }
  return out;
}

function fileList(): string[] {
  return walkFiles(join(APP_DIR, "dist"), APP_DIR, []);
}

function productionDeps(): Set<string> {
  const closure = new Set<string>();
  const visit = (pkgDir: string): void => {
    const pkgPath = join(pkgDir, "package.json");
    if (!existsSync(pkgPath)) return;
    const pkg = JSON.parse(readFileSync(pkgPath, "utf8")) as { dependencies?: Record<string, string> };
    for (const dep of Object.keys(pkg.dependencies ?? {})) {
      if (closure.has(dep)) continue;
      closure.add(dep);
      const found = join(pkgDir, "node_modules", dep);
      if (existsSync(found)) visit(found);
    }
  };
  visit(APP_DIR);
  return closure;
}

function mainProcessImports(): Map<string, string[]> {
  const imports = new Map<string, string[]>();
  const source = readFileSync(join(APP_DIR, "dist/main/main.js"), "utf8");
  const specs = [...source.matchAll(/^\s*(?:import|export)[^'"`]*?\bfrom\s+["']([^"']+)["']/gm)].map((m) => m[1] ?? "");
  specs.push(...[...source.matchAll(/^\s*import\s+["']([^"']+)["']/gm)].map((m) => m[1] ?? ""));
  for (const spec of specs) {
    if (spec.startsWith(".") || spec.startsWith("node:")) continue;
    const top = spec.startsWith("@") ? spec.split("/").slice(0, 2).join("/") : spec.split("/")[0] ?? spec;
    if (imports.has(top)) continue;
    imports.set(top, []);
    try {
      findPkgDir(top);
    } catch {
      imports.set(top, [spec]);
    }
  }
  return imports;
}

/** Node-style node_modules walk upward from the app dir (follows symlinks). */
function findPkgDir(top: string): string {
  let dir = APP_DIR;
  for (;;) {
    const candidate = join(dir, "node_modules", top);
    if (existsSync(join(candidate, "package.json"))) return candidate;
    const parent = dirname(dir);
    if (parent === dir) throw new Error(`cannot find package ${top}`);
    dir = parent;
  }
}

describe("electron-builder config (F4 editor distribution)", () => {
  it("is valid and pins appId/productName/output/targets", () => {
    expect(typeof config).toBe("object");
    expect(config.appId).toBe("com.nengine.editor");
    expect(config.productName).toBe("nEngine Editor");
    expect(config.directories).toMatchObject({ output: "dist-app" });

    const linux = config.linux as { target?: string[]; category?: string };
    expect(asStringList(linux?.target)).toContain("AppImage");
    expect(linux?.category).toBe("Development");

    const win = config.win as { target?: string[] };
    expect(asStringList(win?.target)).toContain("nsis");

    const files = asStringList(config.files);
    expect(files).toContain("dist/**");
    expect(files).toContain("package.json");
  });

  it("main/scripts point at the packaged layout (dist-app, electron-builder --linux)", () => {
    expect(PACKAGE_JSON.main).toBe("dist/main/main.js");
    expect(PACKAGE_JSON.scripts?.dist).toBe("electron-builder --linux");
    expect(PACKAGE_JSON.scripts?.["dist:win"]).toBe("electron-builder --win");
  });

  it("files globs cover the compiled entrypoints of a fresh build output", () => {
    expect(existsSync(join(APP_DIR, "dist/main/main.js"))).toBe(true);
    expect(existsSync(join(APP_DIR, "dist/preload/preload.js"))).toBe(true);
    expect(existsSync(join(APP_DIR, "dist/renderer/index.html"))).toBe(true);

    const files = asStringList(config.files);
    const listing = fileList();
    expect(listing).toContain("dist/main/main.js");
    expect(listing).toContain("dist/main/mcp-stdio.js");
    expect(listing).toContain("dist/preload/preload.js");
    expect(listing).toContain("dist/renderer/index.html");

    const covered = new Set(listing.filter((rel) => files.some((pattern) => globMatches(pattern, rel))));
    expect(covered.has("dist/main/main.js")).toBe(true);
    expect(covered.has("dist/main/mcp-stdio.js")).toBe(true);
    expect(covered.has("dist/preload/preload.js")).toBe(true);
    expect(covered.has("dist/renderer/index.html")).toBe(true);
    expect(covered.size).toBeGreaterThan(0);
  });

  it("main-process runtime imports resolve inside the production dependency closure", () => {
    const closure = productionDeps();
    const unresolvable = mainProcessImports();
    for (const [top, missing] of unresolvable) {
      // electron is provided by the Electron runtime binary, not packaged
      if (top === "electron") continue;
      expect(missing, `cannot resolve ${top} from the compiled main process`).toEqual([]);
      expect(closure.has(top), `@nengine/editor must declare ${top} (or a dependency chain to it) as a runtime dependency`).toBe(true);
    }
    expect(closure.has("vite")).toBe(true);
    expect(closure.has("@modelcontextprotocol/sdk")).toBe(true);
  });
});