import { spawnSync } from "node:child_process";
import { createHash } from "node:crypto";
import { mkdirSync, readdirSync, readFileSync, writeFileSync } from "node:fs";
import path from "node:path";
import { fileURLToPath, pathToFileURL } from "node:url";

function dedupe(values: string[]): string[] {
  const seen = new Set<string>();
  const out: string[] = [];
  for (const value of values) {
    if (!value || seen.has(value)) {
      continue;
    }
    seen.add(value);
    out.push(value);
  }
  return out;
}

const scriptPath = fileURLToPath(import.meta.url);
const scriptDir = path.dirname(scriptPath);
const rootDir = path.resolve(scriptDir, "..");
const distDir = path.join(rootDir, "dist");
const outputPath = path.join(distDir, "cli-startup-metadata.json");
const extensionsDir = path.join(rootDir, "extensions");
const CORE_CHANNEL_ORDER = [
  "telegram",
  "whatsapp",
  "discord",
  "irc",
  "googlechat",
  "slack",
  "signal",
  "imessage",
] as const;

type ExtensionChannelEntry = {
  id: string;
  order: number;
  label: string;
};

type BundledChannelCatalog = {
  ids: string[];
  signature: string;
};

function resolveRootHelpBundleIdentity(
  distDirOverride: string = distDir,
): { bundleName: string; signature: string } | null {
  const bundleName = readdirSync(distDirOverride).find(
    (entry) => entry.startsWith("root-help-") && entry.endsWith(".js"),
  );
  if (!bundleName) {
    return null;
  }
  const bundlePath = path.join(distDirOverride, bundleName);
  const raw = readFileSync(bundlePath, "utf8");
  return {
    bundleName,
    signature: createHash("sha1").update(raw).digest("hex"),
  };
}

export function readBundledChannelCatalog(
  extensionsDirOverride: string = extensionsDir,
): BundledChannelCatalog {
  const entries: ExtensionChannelEntry[] = [];
  const signature = createHash("sha1");
  for (const dirEntry of readdirSync(extensionsDirOverride, { withFileTypes: true })) {
    if (!dirEntry.isDirectory()) {
      continue;
    }
    const packageJsonPath = path.join(extensionsDirOverride, dirEntry.name, "package.json");
    try {
      const raw = readFileSync(packageJsonPath, "utf8");
      signature.update(`${dirEntry.name}\0${raw}\0`);
      const parsed = JSON.parse(raw) as {
        openclaw?: {
          channel?: {
            id?: unknown;
            order?: unknown;
            label?: unknown;
          };
        };
      };
      const id = parsed.openclaw?.channel?.id;
      if (typeof id !== "string" || !id.trim()) {
        continue;
      }
      const orderRaw = parsed.openclaw?.channel?.order;
      const labelRaw = parsed.openclaw?.channel?.label;
      entries.push({
        id: id.trim(),
        order: typeof orderRaw === "number" ? orderRaw : 999,
        label: typeof labelRaw === "string" ? labelRaw : id.trim(),
      });
    } catch {
      // Ignore malformed or missing extension package manifests.
    }
  }
  return {
    ids: entries
      .toSorted((a, b) =>
        a.order === b.order ? a.label.localeCompare(b.label) : a.order - b.order,
      )
      .map((entry) => entry.id),
    signature: signature.digest("hex"),
  };
}

export function readBundledChannelCatalogIds(
  extensionsDirOverride: string = extensionsDir,
): string[] {
  return readBundledChannelCatalog(extensionsDirOverride).ids;
}

export async function renderBundledRootHelpText(
  _distDirOverride: string = distDir,
): Promise<string> {
  const bundleIdentity = resolveRootHelpBundleIdentity(_distDirOverride);
  if (!bundleIdentity) {
    throw new Error("No root-help bundle found in dist; cannot write CLI startup metadata.");
  }
  const moduleUrl = pathToFileURL(path.join(_distDirOverride, bundleIdentity.bundleName)).href;
  const inlineModule = [
    `const mod = await import(${JSON.stringify(moduleUrl)});`,
    "if (typeof mod.outputRootHelp !== 'function') {",
    `  throw new Error(${JSON.stringify(`Bundle ${bundleIdentity.bundleName} does not export outputRootHelp.`)});`,
    "}",
    "await mod.outputRootHelp();",
    "process.exit(0);",
  ].join("\n");
  const result = spawnSync(process.execPath, ["--input-type=module", "--eval", inlineModule], {
    cwd: _distDirOverride,
    encoding: "utf8",
    timeout: 30_000,
  });
  if (result.error) {
    throw result.error;
  }
  if (result.status !== 0) {
    const stderr = result.stderr?.trim();
    throw new Error(
      `Failed to render bundled root help from ${bundleIdentity.bundleName}` +
        (stderr ? `: ${stderr}` : result.signal ? `: terminated by ${result.signal}` : ""),
    );
  }
  return result.stdout ?? "";
}

async function renderSourceRootHelpText(): Promise<string> {
  const module = await import("../src/cli/program/root-help.ts");
  return module.renderRootHelpText({ pluginSdkResolution: "src" });
}

export async function writeCliStartupMetadata(options?: {
  distDir?: string;
  outputPath?: string;
  extensionsDir?: string;
}): Promise<void> {
  const resolvedDistDir = options?.distDir ?? distDir;
  const resolvedOutputPath = options?.outputPath ?? outputPath;
  const resolvedExtensionsDir = options?.extensionsDir ?? extensionsDir;
  const channelCatalog = readBundledChannelCatalog(resolvedExtensionsDir);
  const bundleIdentity = resolveRootHelpBundleIdentity(resolvedDistDir);
  const channelOptions = dedupe([...CORE_CHANNEL_ORDER, ...channelCatalog.ids]);

  try {
    const existing = JSON.parse(readFileSync(resolvedOutputPath, "utf8")) as {
      rootHelpBundleSignature?: unknown;
      channelCatalogSignature?: unknown;
    };
    if (
      bundleIdentity &&
      existing.rootHelpBundleSignature === bundleIdentity.signature &&
      existing.channelCatalogSignature === channelCatalog.signature
    ) {
      return;
    }
  } catch {
    // Missing or malformed existing metadata means we should regenerate it.
  }

  let rootHelpText: string;
  try {
    rootHelpText = await renderBundledRootHelpText(resolvedDistDir);
  } catch {
    rootHelpText = await renderSourceRootHelpText();
  }

  mkdirSync(resolvedDistDir, { recursive: true });
  writeFileSync(
    resolvedOutputPath,
    `${JSON.stringify(
      {
        generatedBy: "scripts/write-cli-startup-metadata.ts",
        channelOptions,
        channelCatalogSignature: channelCatalog.signature,
        rootHelpBundleSignature: bundleIdentity?.signature ?? null,
        rootHelpText,
      },
      null,
      2,
    )}\n`,
    "utf8",
  );
}

if (process.argv[1] && path.resolve(process.argv[1]) === scriptPath) {
  await writeCliStartupMetadata();
  process.exit(0);
}