import fs from "node:fs/promises";
import path from "node:path";
import { resolveOpenClawPackageRootSync } from "../infra/openclaw-root.js";

type PluginPeerLinkLogger = {
  info?: (message: string) => void;
  warn?: (message: string) => void;
};

type RelinkManagedNpmRootResult = {
  checked: number;
  attempted: number;
  repaired: number;
  skipped: number;
};

type OpenClawPeerLinkAuditIssue = {
  packageName: string;
  packageDir: string;
  reason: string;
};

type AuditManagedNpmRootResult = {
  checked: number;
  broken: number;
  issues: OpenClawPeerLinkAuditIssue[];
};

type OpenClawPeerLinkResult = "linked" | "skipped" | "unchanged";

function readStringRecord(value: unknown): Record<string, string> {
  if (typeof value !== "object" || value === null || Array.isArray(value)) {
    return {};
  }
  const record: Record<string, string> = {};
  for (const [key, raw] of Object.entries(value)) {
    if (typeof raw === "string") {
      record[key] = raw;
    }
  }
  return record;
}

async function readPackagePeerDependencies(packageDir: string): Promise<Record<string, string>> {
  try {
    const raw = await fs.readFile(path.join(packageDir, "package.json"), "utf8");
    const parsed = JSON.parse(raw) as { peerDependencies?: unknown };
    return readStringRecord(parsed.peerDependencies);
  } catch (error) {
    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
      return {};
    }
    throw error;
  }
}

async function listManagedNpmRootPackageDirs(npmRoot: string): Promise<string[]> {
  const nodeModulesDir = path.join(npmRoot, "node_modules");
  let entries: import("node:fs").Dirent[];
  try {
    entries = await fs.readdir(nodeModulesDir, { withFileTypes: true });
  } catch (error) {
    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
      return [];
    }
    throw error;
  }

  const packageDirs: string[] = [];
  for (const entry of entries) {
    if (!entry.isDirectory() || entry.name === ".bin") {
      continue;
    }
    const entryPath = path.join(nodeModulesDir, entry.name);
    if (entry.name.startsWith("@")) {
      const scopedEntries = await fs.readdir(entryPath, { withFileTypes: true }).catch((error) => {
        if ((error as NodeJS.ErrnoException).code === "ENOENT") {
          return [];
        }
        throw error;
      });
      for (const scopedEntry of scopedEntries) {
        if (scopedEntry.isDirectory()) {
          packageDirs.push(path.join(entryPath, scopedEntry.name));
        }
      }
      continue;
    }
    if (!entry.name.startsWith(".")) {
      packageDirs.push(entryPath);
    }
  }
  return packageDirs.toSorted((a, b) => a.localeCompare(b));
}

async function safeRealpath(filePath: string): Promise<string | null> {
  try {
    return await fs.realpath(filePath);
  } catch {
    return null;
  }
}

function managedPackageNameFromDir(params: { npmRoot: string; packageDir: string }): string {
  return path
    .relative(path.join(params.npmRoot, "node_modules"), params.packageDir)
    .split(path.sep)
    .join("/");
}

async function auditOpenClawPeerDependency(params: {
  hostRoot: string;
  npmRoot: string;
  packageDir: string;
}): Promise<OpenClawPeerLinkAuditIssue | null> {
  const packageName = managedPackageNameFromDir({
    npmRoot: params.npmRoot,
    packageDir: params.packageDir,
  });
  const nodeModulesDir = path.join(params.packageDir, "node_modules");
  try {
    const existing = await fs.lstat(nodeModulesDir);
    if (!existing.isDirectory() || existing.isSymbolicLink()) {
      return {
        packageName,
        packageDir: params.packageDir,
        reason: `${nodeModulesDir} is not a real directory`,
      };
    }
  } catch (error) {
    if ((error as NodeJS.ErrnoException).code === "ENOENT") {
      return {
        packageName,
        packageDir: params.packageDir,
        reason: `missing ${path.join(nodeModulesDir, "openclaw")}`,
      };
    }
    throw error;
  }

  const linkPath = path.join(nodeModulesDir, "openclaw");
  const currentTarget = await safeRealpath(linkPath);
  if (!currentTarget) {
    return {
      packageName,
      packageDir: params.packageDir,
      reason: `missing ${linkPath}`,
    };
  }
  const expectedTarget = (await safeRealpath(params.hostRoot)) ?? params.hostRoot;
  if (currentTarget !== expectedTarget) {
    return {
      packageName,
      packageDir: params.packageDir,
      reason: `${linkPath} points to ${currentTarget} instead of ${expectedTarget}`,
    };
  }
  return null;
}

async function ensureRealNodeModulesDir(params: {
  installedDir: string;
  logger: PluginPeerLinkLogger;
}): Promise<string | null> {
  const nodeModulesDir = path.join(params.installedDir, "node_modules");
  try {
    const existing = await fs.lstat(nodeModulesDir);
    if (!existing.isDirectory() || existing.isSymbolicLink()) {
      params.logger.warn?.(
        `Skipping openclaw peerDependency link because ${nodeModulesDir} is not a real directory.`,
      );
      return null;
    }
    return nodeModulesDir;
  } catch (error) {
    if ((error as NodeJS.ErrnoException).code !== "ENOENT") {
      throw error;
    }
  }

  await fs.mkdir(nodeModulesDir, { recursive: true });
  const created = await fs.lstat(nodeModulesDir);
  if (!created.isDirectory() || created.isSymbolicLink()) {
    params.logger.warn?.(
      `Skipping openclaw peerDependency link because ${nodeModulesDir} is not a real directory.`,
    );
    return null;
  }
  return nodeModulesDir;
}

async function linkOpenClawPeerDependency(params: {
  hostRoot: string;
  installedDir: string;
  peerName: string;
  logger: PluginPeerLinkLogger;
}): Promise<OpenClawPeerLinkResult> {
  const nodeModulesDir = await ensureRealNodeModulesDir({
    installedDir: params.installedDir,
    logger: params.logger,
  });
  if (!nodeModulesDir) {
    return "skipped";
  }

  const linkPath = path.join(nodeModulesDir, params.peerName);
  const expectedTarget = (await safeRealpath(params.hostRoot)) ?? params.hostRoot;
  const currentTarget = await safeRealpath(linkPath);
  if (currentTarget === expectedTarget) {
    return "unchanged";
  }

  try {
    await fs.rm(linkPath, { recursive: true, force: true });
    await fs.symlink(params.hostRoot, linkPath, "junction");
    params.logger.info?.(`Linked peerDependency "${params.peerName}" -> ${params.hostRoot}`);
    return "linked";
  } catch (err) {
    params.logger.warn?.(`Failed to symlink peerDependency "${params.peerName}": ${String(err)}`);
    return "skipped";
  }
}

/**
 * Symlink the host openclaw package for plugins that declare it as a peer.
 * Plugin package managers still own third-party dependencies; this only wires
 * the host SDK package into the plugin-local Node graph.
 */
export async function linkOpenClawPeerDependencies(params: {
  installedDir: string;
  peerDependencies: Record<string, string>;
  logger: PluginPeerLinkLogger;
}): Promise<{ repaired: number; skipped: number }> {
  const peers = Object.keys(params.peerDependencies).filter((name) => name === "openclaw");
  if (peers.length === 0) {
    return { repaired: 0, skipped: 0 };
  }

  const hostRoot = resolveOpenClawPackageRootSync({
    argv1: process.argv[1],
    moduleUrl: import.meta.url,
    cwd: process.cwd(),
  });
  if (!hostRoot) {
    params.logger.warn?.(
      "Could not locate openclaw package root to symlink peerDependencies; plugin may fail to resolve openclaw at runtime.",
    );
    return { repaired: 0, skipped: peers.length };
  }

  let repaired = 0;
  let skipped = 0;
  for (const peerName of peers) {
    const result = await linkOpenClawPeerDependency({
      hostRoot,
      installedDir: params.installedDir,
      peerName,
      logger: params.logger,
    });
    if (result === "linked") {
      repaired += 1;
    } else if (result === "skipped") {
      skipped += 1;
    }
  }
  return { repaired, skipped };
}

export async function relinkOpenClawPeerDependenciesInManagedNpmRoot(params: {
  npmRoot: string;
  logger: PluginPeerLinkLogger;
}): Promise<RelinkManagedNpmRootResult> {
  let checked = 0;
  let attempted = 0;
  let repaired = 0;
  let skipped = 0;
  for (const packageDir of await listManagedNpmRootPackageDirs(params.npmRoot)) {
    const peerDependencies = await readPackagePeerDependencies(packageDir);
    if (!Object.hasOwn(peerDependencies, "openclaw")) {
      continue;
    }
    checked += 1;
    const result = await linkOpenClawPeerDependencies({
      installedDir: packageDir,
      peerDependencies,
      logger: params.logger,
    });
    attempted += 1;
    repaired += result.repaired;
    skipped += result.skipped;
  }
  return { checked, attempted, repaired, skipped };
}

export async function auditOpenClawPeerDependenciesInManagedNpmRoot(params: {
  npmRoot: string;
}): Promise<AuditManagedNpmRootResult> {
  const hostRoot = resolveOpenClawPackageRootSync({
    argv1: process.argv[1],
    moduleUrl: import.meta.url,
    cwd: process.cwd(),
  });
  if (!hostRoot) {
    return { checked: 0, broken: 0, issues: [] };
  }

  let checked = 0;
  const issues: OpenClawPeerLinkAuditIssue[] = [];
  for (const packageDir of await listManagedNpmRootPackageDirs(params.npmRoot)) {
    const peerDependencies = await readPackagePeerDependencies(packageDir);
    if (!Object.hasOwn(peerDependencies, "openclaw")) {
      continue;
    }
    checked += 1;
    const issue = await auditOpenClawPeerDependency({
      hostRoot,
      npmRoot: params.npmRoot,
      packageDir,
    });
    if (issue) {
      issues.push(issue);
    }
  }
  return { checked, broken: issues.length, issues };
}