/** Shared Computer Use plugin cache reconciliation for isolated Codex homes. */
import fs from "node:fs/promises";
import path from "node:path";
import type { ResolvedCodexComputerUseConfig } from "./config.js";
import {
  resolveFirstExistingMacOSDesktopCodexBundledMarketplacePath,
  resolveMacOSDesktopCodexBundledMarketplaceCandidates,
} from "./desktop-app-paths.js";

type CodexComputerUsePluginCacheRepairResult =
  | {
      status: "disabled" | "explicit_marketplace" | "independent" | "source_missing" | "shared";
      changed: boolean;
      message: string;
      cachePath?: string;
      targetPath?: string;
      version?: string;
      removedStaleVersions: string[];
      warnings: string[];
    }
  | {
      status: "failed";
      changed: false;
      message: string;
      removedStaleVersions: string[];
      warnings: string[];
    };

const DEFAULT_CODEX_COMPUTER_USE_BUNDLED_MARKETPLACE_PATH =
  resolveMacOSDesktopCodexBundledMarketplaceCandidates("darwin")[0] ?? "";

const DEFAULT_BUNDLED_MARKETPLACE_NAME = "openai-bundled";

export async function ensureCodexComputerUseSharedPluginCache(params: {
  codexHome: string;
  config: ResolvedCodexComputerUseConfig;
  bundledMarketplacePath?: string;
  bundledMarketplacePathCandidates?: readonly string[];
}): Promise<CodexComputerUsePluginCacheRepairResult> {
  if (!params.config.enabled) {
    return skippedCacheResult(
      "disabled",
      "Computer Use cache sharing skipped because it is disabled.",
    );
  }
  if (params.config.pluginCacheMode === "independent") {
    return skippedCacheResult(
      "independent",
      "Computer Use cache sharing skipped because pluginCacheMode is independent.",
    );
  }
  if (params.config.marketplaceName || params.config.marketplacePath) {
    return skippedCacheResult(
      "explicit_marketplace",
      "Computer Use cache sharing skipped because an explicit marketplace is configured.",
    );
  }

  const bundledMarketplacePath = resolveComputerUseBundledMarketplacePath(params);
  const sourcePluginRoot = path.join(bundledMarketplacePath, "plugins", params.config.pluginName);
  const version = await readBundledPluginVersion(sourcePluginRoot);
  if (!version) {
    return skippedCacheResult(
      "source_missing",
      `Computer Use bundled plugin source was not found at ${sourcePluginRoot}.`,
    );
  }

  const marketplaceName = params.config.marketplaceName ?? DEFAULT_BUNDLED_MARKETPLACE_NAME;
  const cacheRoot = path.join(
    params.codexHome,
    "plugins",
    "cache",
    marketplaceName,
    params.config.pluginName,
  );
  const cachePath = path.join(cacheRoot, version);
  const changed = await ensureRealDirectoryCopy(cachePath, sourcePluginRoot, version);
  return {
    status: "shared",
    changed,
    cachePath,
    targetPath: sourcePluginRoot,
    version,
    removedStaleVersions: [],
    warnings: [],
    message: `Computer Use plugin cache ${cachePath} contains bundled plugin ${sourcePluginRoot}.`,
  };
}

function resolveComputerUseBundledMarketplacePath(params: {
  bundledMarketplacePath?: string;
  bundledMarketplacePathCandidates?: readonly string[];
}): string {
  return (
    params.bundledMarketplacePath ??
    resolveFirstExistingMacOSDesktopCodexBundledMarketplacePath({
      candidates: params.bundledMarketplacePathCandidates,
    }) ??
    params.bundledMarketplacePathCandidates?.[0] ??
    DEFAULT_CODEX_COMPUTER_USE_BUNDLED_MARKETPLACE_PATH
  );
}

async function readBundledPluginVersion(sourcePluginRoot: string): Promise<string | undefined> {
  const pluginJsonPath = path.join(sourcePluginRoot, ".codex-plugin", "plugin.json");
  let raw: string;
  try {
    raw = await fs.readFile(pluginJsonPath, "utf8");
  } catch {
    return undefined;
  }
  try {
    const parsed = JSON.parse(raw) as { version?: unknown };
    return typeof parsed.version === "string" && parsed.version.trim()
      ? parsed.version.trim()
      : undefined;
  } catch {
    return undefined;
  }
}

async function ensureRealDirectoryCopy(
  cachePath: string,
  sourcePluginRoot: string,
  version: string,
): Promise<boolean> {
  await fs.mkdir(path.dirname(cachePath), { recursive: true });
  const stat = await fs.lstat(cachePath).catch(() => undefined);
  if (stat?.isDirectory() && !stat.isSymbolicLink()) {
    const cachedVersion = await readBundledPluginVersion(cachePath);
    if (cachedVersion === version) {
      return false;
    }
  }
  const cacheRoot = path.dirname(cachePath);
  const cacheName = path.basename(cachePath);
  const stagingRoot = await fs.mkdtemp(path.join(cacheRoot, `.${cacheName}.staging-`));
  const stagedPath = path.join(stagingRoot, cacheName);
  const backupPath = path.join(cacheRoot, `.${cacheName}.backup-${process.pid}-${Date.now()}`);
  let backupCreated = false;
  try {
    await fs.cp(sourcePluginRoot, stagedPath, { recursive: true });
    if (stat) {
      await fs.rename(cachePath, backupPath);
      backupCreated = true;
    }
    try {
      await fs.rename(stagedPath, cachePath);
    } catch (error) {
      if (backupCreated) {
        try {
          await fs.rename(backupPath, cachePath);
          backupCreated = false;
        } catch (restoreError) {
          throw new Error(
            `Failed to install Computer Use cache ${cachePath} and restore its prior copy: ${String(error)}`,
            { cause: restoreError },
          );
        }
      }
      throw error;
    }
    if (backupCreated) {
      await fs.rm(backupPath, { recursive: true, force: true });
    }
    return true;
  } finally {
    await fs.rm(stagingRoot, { recursive: true, force: true });
  }
}

function skippedCacheResult(
  status: "disabled" | "explicit_marketplace" | "independent" | "source_missing",
  message: string,
): CodexComputerUsePluginCacheRepairResult {
  return {
    status,
    changed: false,
    message,
    removedStaleVersions: [],
    warnings: status === "source_missing" ? [message] : [],
  };
}