import {
  cp,
  lstat,
  mkdir,
  mkdtemp,
  readFile,
  realpath,
  rm,
  symlink,
  writeFile,
} from "node:fs/promises";
import { tmpdir } from "node:os";
import path from "node:path";
import { fileURLToPath } from "node:url";

/**
 * Generated module fixtures for the packager's tests: a built module directory in a temporary
 * location, whose `node_modules` links to the real Module SDK and Drizzle this package depends on.
 * Everything a development module directory holds is there, including what must never ship
 * (`src/`, `tests/`, declarations, source maps, `workspace:` ranges), so a test can prove the
 * packager leaves it out.
 */

const packageRoot = path.resolve(path.dirname(fileURLToPath(import.meta.url)), "..", "..");

export interface FakePackage {
  readonly name: string;
  readonly version?: string;
  readonly packageJson?: Record<string, unknown>;
  /** Files relative to the fake package's root. */
  readonly files?: Record<string, string | Uint8Array>;
}

export interface FixtureModuleOptions {
  readonly databaseAbi?: 1;
  readonly id?: string;
  readonly license?: unknown;
  readonly licenseText?: string | Uint8Array;
  readonly version?: string;
  readonly serverSource?: string;
  readonly withModuleDatabase?: boolean;
  readonly withSchema?: boolean;
  /** The module's `engines` field; omitted from `package.json` when `null`. */
  readonly engines?: Record<string, unknown> | null;
  /** How the module's `@ekklesia/*` dependencies are installed: linked to this workspace's packages
   * (the default), or copied as real directories into a flat `node_modules`, as a registry install
   * lays them out. */
  readonly ekklesiaInstall?: "workspace" | "registry";
  readonly fakePackages?: readonly FakePackage[];
  readonly manifest?: (manifest: Record<string, unknown>) => Record<string, unknown>;
}

const temporaryDirectories: string[] = [];

export async function cleanupFixtures(): Promise<void> {
  await Promise.all(
    temporaryDirectories
      .splice(0)
      .map((directory) => rm(directory, { force: true, recursive: true })),
  );
}

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

async function write(file: string, contents: string | Uint8Array): Promise<void> {
  await mkdir(path.dirname(file), { recursive: true });
  await writeFile(file, contents);
}

const defaultServer = (
  id: string,
  version: string,
  databaseAbi?: 1,
) => `import { defineModuleRuntime } from "@ekklesia/module-sdk";
export default defineModuleRuntime({ ${databaseAbi === 1 ? "database: { abi: 1 }, " : ""}id: ${JSON.stringify(id)}, version: ${JSON.stringify(version)}, register() {} });
`;

const schemaSource = (id: string, databaseAbi?: 1) => `import { createModuleTable${
  databaseAbi === 1 ? ", moduleDrizzleSchemaMetadata" : ""
} } from "@ekklesia/module-database/drizzle";
import { text, uuid } from "drizzle-orm/pg-core";
export const records = createModuleTable(${JSON.stringify(id)})("records", {
  id: uuid("id").primaryKey(),
  value: text("value").notNull(),
});
export default ${
  databaseAbi === 1
    ? `moduleDrizzleSchemaMetadata(${JSON.stringify(id)}, { records })`
    : `{ moduleId: ${JSON.stringify(id)}, tables: { records } }`
};
`;

export async function fixtureModule(options: FixtureModuleOptions = {}): Promise<string> {
  const id = options.id ?? "example";
  const version = options.version ?? "0.1.0";
  const root = await scratchDirectory("ekklesia-pack-fixture-");
  const moduleDirectory = path.join(root, id);
  const tableName = `${id.replaceAll("-", "_")}_records`;
  const usesModuleDatabase =
    options.withModuleDatabase || options.withSchema || options.databaseAbi === 1;
  const engines = options.engines === undefined ? { node: ">=24.11.0 <25" } : options.engines;

  const baseManifest: Record<string, unknown> = {
    manifestVersion: 8,
    id,
    name: `${id} module`,
    version,
    compatibility: { platform: "^0.1.0", moduleSdk: "^0.1.0" },
    ...(options.databaseAbi === 1 ? { database: { abi: 1 } } : {}),
    capabilities: [],
    permissions: [],
    entrypoints: {
      server: "./dist/server/index.js",
      ...(options.withSchema ? { schema: "./dist/schema/index.js" } : {}),
      migrations: "./drizzle",
    },
  };
  const manifest = options.manifest ? options.manifest(baseManifest) : baseManifest;

  await write(
    path.join(moduleDirectory, "ekklesia.module.json"),
    `${JSON.stringify(manifest, null, 2)}\n`,
  );
  await write(
    path.join(moduleDirectory, "package.json"),
    `${JSON.stringify(
      {
        name: `@test/module-${id}`,
        version,
        license: Object.hasOwn(options, "license") ? options.license : "MIT",
        private: true,
        type: "module",
        ...(engines === null ? {} : { engines }),
        scripts: { build: "tsc" },
        dependencies: {
          "@ekklesia/module-sdk": "workspace:*",
          ...(usesModuleDatabase ? { "@ekklesia/module-database": "workspace:*" } : {}),
          "drizzle-orm": "0.45.2",
        },
        devDependencies: { typescript: "7.0.2" },
        exports: { ".": "./dist/server/index.js" },
        ekklesia: { layer: "module" },
      },
      null,
      2,
    )}\n`,
  );
  await write(
    path.join(moduleDirectory, "LICENSE"),
    options.licenseText ?? "MIT License\n\nCopyright (c) 2026 Example Module\n",
  );
  await write(
    path.join(moduleDirectory, "dist/server/index.js"),
    options.serverSource ?? defaultServer(id, version, options.databaseAbi),
  );
  await write(path.join(moduleDirectory, "dist/server/index.js.map"), '{"version":3}\n');
  await write(path.join(moduleDirectory, "dist/server/index.d.ts"), "export {};\n");
  if (options.withSchema) {
    await write(
      path.join(moduleDirectory, "dist/schema/index.js"),
      schemaSource(id, options.databaseAbi),
    );
  }
  await write(path.join(moduleDirectory, "src/server/index.ts"), "export {};\n");
  await write(path.join(moduleDirectory, "tests/server.test.ts"), "export {};\n");
  await write(path.join(moduleDirectory, "README.md"), "# Development notes\n");

  await write(
    path.join(moduleDirectory, "drizzle/0000_initial.sql"),
    `CREATE TABLE "${tableName}" ("id" uuid PRIMARY KEY NOT NULL, "value" text NOT NULL);\n`,
  );
  await write(
    path.join(moduleDirectory, "drizzle/meta/_journal.json"),
    JSON.stringify({
      version: "7",
      dialect: "postgresql",
      entries: [
        { idx: 0, version: "7", when: 1_700_000_000_000, tag: "0000_initial", breakpoints: true },
      ],
    }),
  );
  await write(
    path.join(moduleDirectory, "drizzle/meta/_ekklesia.json"),
    JSON.stringify({
      version: 1,
      moduleId: id,
      entries: [{ tag: "0000_initial", destructive: { mode: "none" } }],
    }),
  );
  await write(
    path.join(moduleDirectory, "drizzle/meta/0000_snapshot.json"),
    JSON.stringify({
      version: "7",
      dialect: "postgresql",
      id: "10000000-0000-4000-8000-000000000001",
      prevId: "00000000-0000-0000-0000-000000000000",
    }),
  );

  // The module's dependencies: the real packages this package depends on, either linked as a
  // workspace links them, or copied as a registry install would place them.
  const modules = path.join(moduleDirectory, "node_modules");
  await mkdir(path.join(modules, "@ekklesia"), { recursive: true });
  const ekklesiaPackages = [
    "module-sdk",
    ...(usesModuleDatabase ? ["module-database"] : []),
  ] as const;
  if (options.ekklesiaInstall === "registry") {
    await installLikeARegistry(modules, [...ekklesiaPackages, "contracts"]);
  } else {
    for (const name of ekklesiaPackages) {
      await symlink(
        await realpath(path.join(packageRoot, "node_modules", "@ekklesia", name)),
        path.join(modules, "@ekklesia", name),
      );
    }
  }
  await symlink(
    await realpath(path.join(packageRoot, "node_modules", "drizzle-orm")),
    path.join(modules, "drizzle-orm"),
  );
  for (const fake of options.fakePackages ?? []) {
    const fakeRoot = path.join(modules, ...fake.name.split("/"));
    await write(
      path.join(fakeRoot, "package.json"),
      JSON.stringify({
        name: fake.name,
        version: fake.version ?? "1.0.0",
        type: "module",
        main: "index.js",
        license: "MIT",
        ...fake.packageJson,
      }),
    );
    for (const [relative, contents] of Object.entries(fake.files ?? {})) {
      await write(path.join(fakeRoot, relative), contents);
    }
  }
  return moduleDirectory;
}

/**
 * Copies each `@ekklesia/*` package's published files (`package.json`, `dist`, `LICENSE`) into a flat
 * `node_modules` as real directories, and links the third-party packages they depend on beside them:
 * the layout a registry install produces, with nothing pointing back into the workspace's sources.
 */
async function installLikeARegistry(modules: string, names: readonly string[]): Promise<void> {
  for (const name of names) {
    const source = await realpath(path.join(packageRoot, "..", name));
    const target = path.join(modules, "@ekklesia", name);
    await mkdir(target, { recursive: true });
    for (const entry of ["package.json", "dist", "LICENSE"]) {
      await cp(path.join(source, entry), path.join(target, entry), {
        force: false,
        recursive: true,
      }).catch((error: NodeJS.ErrnoException) => {
        if (error.code !== "ENOENT") throw error;
      });
    }
    const manifest = JSON.parse(
      await readFile(path.join(source, "package.json"), "utf8"),
    ) as Record<string, Record<string, string> | undefined>;
    for (const dependency of Object.keys(manifest.dependencies ?? {})) {
      const link = path.join(modules, ...dependency.split("/"));
      if (dependency.startsWith("@ekklesia/") || (await exists(link))) continue;
      await mkdir(path.dirname(link), { recursive: true });
      await symlink(await realpath(path.join(source, "node_modules", dependency)), link);
    }
  }
}

async function exists(file: string): Promise<boolean> {
  try {
    await lstat(file);
    return true;
  } catch {
    return false;
  }
}

export const SOURCE_REVISION = "86ae907f59458508e3277666cdd214f5bd7c1078";

const nativeFixtureSource = path.join(packageRoot, "tests", "fixtures", "native-module");

/**
 * The checked-in native proof module (`tests/fixtures/native-module`), copied to a fresh, unrelated
 * temporary directory with `node_modules` linking the real sharp and Module SDK this package's
 * workspace installed, as a module's own install would provide them.
 */
export async function nativeFixtureModule(): Promise<string> {
  // Inside this package, beside its own node_modules, as a module checkout sits beside its own: a
  // bundle's module keys are paths relative to the module, so a copy in the system temporary
  // directory would bundle paths that climb out of it and into this checkout.
  const fixtures = path.join(packageRoot, ".fixtures");
  await mkdir(fixtures, { recursive: true });
  const root = await realpath(await mkdtemp(path.join(fixtures, "native-")));
  temporaryDirectories.push(root);
  const moduleDirectory = path.join(root, "native-proof");
  await cp(nativeFixtureSource, moduleDirectory, { recursive: true });
  const modules = path.join(moduleDirectory, "node_modules");
  await mkdir(path.join(modules, "@ekklesia"), { recursive: true });
  await symlink(
    await realpath(path.join(packageRoot, "node_modules", "sharp")),
    path.join(modules, "sharp"),
  );
  await symlink(
    await realpath(path.join(packageRoot, "node_modules", "@ekklesia", "module-sdk")),
    path.join(modules, "@ekklesia", "module-sdk"),
  );
  return moduleDirectory;
}

/** The workspace's real installed package, for tests that build fake native packages from it. */
export async function installedPackageFile(...segments: string[]): Promise<string> {
  return realpath(path.join(packageRoot, "node_modules", ...segments));
}