import { mkdir, mkdtemp, rm, symlink, writeFile } from "node:fs/promises";
import { tmpdir } from "node:os";
import path from "node:path";
import { fileURLToPath } from "node:url";
import { afterEach, describe, expect, it } from "vitest";
import {
  discoverModules,
  ModuleDiscoveryError,
  type ModuleDiscoveryIssueCode,
} from "../src/modules/index.js";

interface ModuleFixtureOptions {
  directory?: string;
  manifest?: Record<string, unknown>;
  packageJson?: Record<string, unknown>;
  serverSource?: string;
}

const temporaryDirectories: string[] = [];

afterEach(async () => {
  await Promise.all(
    temporaryDirectories.splice(0).map((directory) => rm(directory, { recursive: true })),
  );
});

async function createModulesDirectory(): Promise<string> {
  const directory = await mkdtemp(path.join(tmpdir(), "ekklesia-modules-"));
  temporaryDirectories.push(directory);
  return directory;
}

function manifestFor(id: string): Record<string, unknown> {
  return {
    manifestVersion: 1,
    id,
    name: `${id} module`,
    version: "0.1.0",
    compatibility: {
      platform: "^0.1.0",
      moduleSdk: "^0.1.0",
    },
    capabilities: [`${id}.records`],
    permissions: [`${id}.records.read`],
    entrypoints: {
      server: "./src/server/index.ts",
    },
  };
}

async function createModule(
  modulesDirectory: string,
  id: string,
  options: ModuleFixtureOptions = {},
): Promise<void> {
  const directoryName = options.directory ?? id;
  const moduleDirectory = path.join(modulesDirectory, directoryName);
  const manifest = options.manifest ?? manifestFor(id);
  const packageJson = options.packageJson ?? {
    name: `@test/module-${id}`,
    version: "0.1.0",
    type: "module",
    ekklesia: { layer: "module" },
  };

  await mkdir(path.join(moduleDirectory, "src/server"), { recursive: true });
  await Promise.all([
    writeFile(path.join(moduleDirectory, "package.json"), JSON.stringify(packageJson)),
    writeFile(path.join(moduleDirectory, "ekklesia.module.json"), JSON.stringify(manifest)),
    writeFile(
      path.join(moduleDirectory, "src/server/index.ts"),
      options.serverSource ?? `export const moduleId = ${JSON.stringify(id)};`,
    ),
  ]);
}

async function discoveryError(
  modulesDirectory: string,
  versions: { moduleSdkVersion?: string; platformVersion?: string } = {},
): Promise<ModuleDiscoveryError> {
  try {
    await discoverModules({
      moduleSdkVersion: versions.moduleSdkVersion ?? "0.1.0",
      modulesDirectory,
      platformVersion: versions.platformVersion ?? "0.1.0",
    });
  } catch (error) {
    if (error instanceof ModuleDiscoveryError) {
      return error;
    }
    throw error;
  }
  throw new Error("Expected module discovery to fail.");
}

function issueCodes(error: ModuleDiscoveryError): ModuleDiscoveryIssueCode[] {
  return error.issues.map((issue) => issue.code);
}

describe("module discovery", () => {
  it("treats a missing or empty modules directory as zero installed modules", async () => {
    const parent = await createModulesDirectory();
    const missing = path.join(parent, "missing");

    await expect(
      discoverModules({
        moduleSdkVersion: "0.1.0",
        modulesDirectory: missing,
        platformVersion: "0.1.0",
      }),
    ).resolves.toEqual([]);
    await expect(
      discoverModules({
        moduleSdkVersion: "0.1.0",
        modulesDirectory: parent,
        platformVersion: "0.1.0",
      }),
    ).resolves.toEqual([]);
  });

  it("discovers static manifests and orders dependencies deterministically", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "calendar", {
      manifest: {
        ...manifestFor("calendar"),
        dependencies: {
          modules: { required: { people: "^0.1.0" } },
          capabilities: { required: ["people.records"] },
        },
        storage: { buckets: [{ id: "assets" }, { id: "exports" }] },
      },
      serverSource: 'throw new Error("discovery must never execute server code");',
    });
    await createModule(modulesDirectory, "people");

    const modules = await discoverModules({
      moduleSdkVersion: "0.1.0",
      modulesDirectory,
      platformVersion: "0.1.0",
    });

    expect(modules.map((module) => module.manifest.id)).toEqual(["people", "calendar"]);
    expect(modules[1]?.manifest.storage.buckets.map((bucket) => bucket.id)).toEqual([
      "assets",
      "exports",
    ]);
    expect(Object.isFrozen(modules[1]?.manifest)).toBe(true);
    const mutableBuckets = modules[1]?.manifest.storage.buckets as unknown as Array<{ id: string }>;
    expect(() => mutableBuckets.push({ id: "tampered" })).toThrow(TypeError);
  });

  it("accepts the repository's cloneable module template", async () => {
    const testDirectory = path.dirname(fileURLToPath(import.meta.url));
    const templatesDirectory = path.resolve(testDirectory, "../../templates");

    const modules = await discoverModules({
      moduleSdkVersion: "0.1.0",
      modulesDirectory: templatesDirectory,
      platformVersion: "0.1.0",
    });

    expect(modules.map((module) => module.manifest.id)).toEqual(["example"]);
  });

  it("aggregates malformed packages and manifests without partial discovery", async () => {
    const modulesDirectory = await createModulesDirectory();
    await mkdir(path.join(modulesDirectory, "missing"));
    await createModule(modulesDirectory, "invalid", {
      manifest: { ...manifestFor("invalid"), renderers: ["not-allowed"] },
      packageJson: {
        name: "@test/module-invalid",
        version: "not-semver",
        type: "commonjs",
      },
    });

    const error = await discoveryError(modulesDirectory);

    expect(issueCodes(error)).toEqual(
      expect.arrayContaining([
        "MODULE_MANIFEST_INVALID",
        "MODULE_MANIFEST_MISSING",
        "MODULE_PACKAGE_INVALID",
        "MODULE_PACKAGE_MISSING",
      ]),
    );
  });

  it("aggregates malformed JSON without exposing machine-specific paths", async () => {
    const modulesDirectory = await createModulesDirectory();
    const moduleDirectory = path.join(modulesDirectory, "broken-json");
    await mkdir(moduleDirectory);
    await Promise.all([
      writeFile(path.join(moduleDirectory, "package.json"), "{"),
      writeFile(path.join(moduleDirectory, "ekklesia.module.json"), "["),
    ]);

    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toEqual(
      expect.arrayContaining(["MODULE_MANIFEST_INVALID", "MODULE_PACKAGE_INVALID"]),
    );
    expect(error.issues.every((issue) => !issue.message.includes(modulesDirectory))).toBe(true);
  });

  it("requires package and manifest versions to match", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "mismatch", {
      packageJson: {
        name: "@test/module-mismatch",
        version: "0.2.0",
        type: "module",
        ekklesia: { layer: "module" },
      },
    });

    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_VERSION_MISMATCH");
  });

  it("rejects duplicate module IDs and package names", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "one", {
      manifest: {
        ...manifestFor("one"),
        id: "shared",
        capabilities: ["shared.records"],
        permissions: ["shared.records.read"],
      },
      packageJson: {
        name: "@test/duplicate",
        version: "0.1.0",
        type: "module",
        ekklesia: { layer: "module" },
      },
    });
    await createModule(modulesDirectory, "two", {
      manifest: {
        ...manifestFor("two"),
        id: "shared",
        capabilities: ["shared.records"],
        permissions: ["shared.records.read"],
      },
      packageJson: {
        name: "@test/duplicate",
        version: "0.1.0",
        type: "module",
        ekklesia: { layer: "module" },
      },
    });

    const error = await discoveryError(modulesDirectory);

    expect(issueCodes(error)).toEqual(
      expect.arrayContaining(["MODULE_ID_DUPLICATE", "MODULE_PACKAGE_NAME_DUPLICATE"]),
    );
  });

  it("enforces platform and Module SDK compatibility", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "future", {
      manifest: {
        ...manifestFor("future"),
        compatibility: { platform: ">=1.0.0", moduleSdk: ">=2.0.0" },
      },
    });

    const error = await discoveryError(modulesDirectory);

    expect(issueCodes(error)).toEqual(
      expect.arrayContaining(["MODULE_PLATFORM_INCOMPATIBLE", "MODULE_SDK_INCOMPATIBLE"]),
    );
  });

  it("allows missing optional dependencies but rejects missing required dependencies", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "optional-consumer", {
      manifest: {
        ...manifestFor("optional-consumer"),
        dependencies: { modules: { optional: { absent: "^1.0.0" } } },
      },
    });

    await expect(
      discoverModules({
        moduleSdkVersion: "0.1.0",
        modulesDirectory,
        platformVersion: "0.1.0",
      }),
    ).resolves.toHaveLength(1);

    await createModule(modulesDirectory, "required-consumer", {
      manifest: {
        ...manifestFor("required-consumer"),
        dependencies: { modules: { required: { absent: "^1.0.0" } } },
      },
    });
    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_DEPENDENCY_MISSING");
  });

  it("rejects installed dependencies with incompatible versions", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "people");
    await createModule(modulesDirectory, "calendar", {
      manifest: {
        ...manifestFor("calendar"),
        dependencies: { modules: { optional: { people: "^2.0.0" } } },
      },
    });

    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_DEPENDENCY_INCOMPATIBLE");
  });

  it("rejects missing required capabilities", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "consumer", {
      manifest: {
        ...manifestFor("consumer"),
        dependencies: { capabilities: { required: ["people.records"] } },
      },
    });
    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_CAPABILITY_MISSING");
  });

  it("detects dependency cycles", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "one", {
      manifest: {
        ...manifestFor("one"),
        dependencies: { modules: { required: { two: "^0.1.0" } } },
      },
    });
    await createModule(modulesDirectory, "two", {
      manifest: {
        ...manifestFor("two"),
        dependencies: { modules: { required: { one: "^0.1.0" } } },
      },
    });
    await createModule(modulesDirectory, "three", {
      manifest: {
        ...manifestFor("three"),
        dependencies: { modules: { required: { two: "^0.1.0" } } },
      },
    });

    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_DEPENDENCY_CYCLE");
    expect(error.issues.find((issue) => issue.code === "MODULE_DEPENDENCY_CYCLE")?.message).toBe(
      "Module dependency cycle contains: one, two.",
    );
  });

  it("rejects missing entrypoint targets and invalid caller versions", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "missing-server", {
      manifest: {
        ...manifestFor("missing-server"),
        entrypoints: { server: "./src/server/missing.ts" },
      },
    });

    let error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_ENTRYPOINT_MISSING");

    error = await discoveryError(modulesDirectory, { platformVersion: "invalid" });
    expect(issueCodes(error)).toContain("DISCOVERY_CONFIGURATION_INVALID");
  });

  it("requires executable entrypoints to be files and migrations to be a directory", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "wrong-entrypoint-kind", {
      manifest: {
        ...manifestFor("wrong-entrypoint-kind"),
        entrypoints: {
          server: "./src/server",
          migrations: "./src/server/index.ts",
        },
      },
    });

    const error = await discoveryError(modulesDirectory);
    expect(error.issues.filter((issue) => issue.code === "MODULE_ENTRYPOINT_INVALID")).toHaveLength(
      2,
    );
  });

  it("rejects package metadata links that escape the module directory", async () => {
    const modulesDirectory = await createModulesDirectory();
    await createModule(modulesDirectory, "linked");
    const externalManifest = path.join(modulesDirectory, "external-manifest.json");
    const linkedManifest = path.join(modulesDirectory, "linked", "ekklesia.module.json");
    await writeFile(externalManifest, JSON.stringify(manifestFor("linked")));
    await rm(linkedManifest);
    await symlink("../external-manifest.json", linkedManifest);

    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_MANIFEST_INVALID");
  });

  it("rejects symbolic links masquerading as installed module directories", async () => {
    const modulesDirectory = await createModulesDirectory();
    const externalModules = await createModulesDirectory();
    await createModule(externalModules, "outside");
    await symlink(
      path.join(externalModules, "outside"),
      path.join(modulesDirectory, "linked-module"),
      "dir",
    );

    const error = await discoveryError(modulesDirectory);
    expect(issueCodes(error)).toContain("MODULE_DIRECTORY_INVALID");
  });

  it("produces stable diagnostics independent of the absolute modules path", async () => {
    const firstModulesDirectory = await createModulesDirectory();
    const secondModulesDirectory = await createModulesDirectory();
    await mkdir(path.join(firstModulesDirectory, "broken"));
    await mkdir(path.join(secondModulesDirectory, "broken"));

    const [firstError, secondError] = await Promise.all([
      discoveryError(firstModulesDirectory),
      discoveryError(secondModulesDirectory),
    ]);

    expect(firstError.issues).toEqual(secondError.issues);
  });
});