import { access, realpath } from 'node:fs/promises';
import { constants } from 'node:fs';
import { createRequire } from 'node:module';
import { dirname, join } from 'node:path';
import { spawnSync } from 'node:child_process';
import { getBaseDir } from 'ee-core/ps';

/** 移植自 Noobi.ai src/main/codexLocator.ts，改动：去掉 ChatGPT.app 分支、改用 CJS 可用的 require 基准、增加不抛错的探测入口 */
const TARGETS: Record<string, { packageName: string; triple: string; executable: string }> = {
  'darwin-arm64': {
    packageName: '@openai/codex-darwin-arm64',
    triple: 'aarch64-apple-darwin',
    executable: 'codex',
  },
  'darwin-x64': {
    packageName: '@openai/codex-darwin-x64',
    triple: 'x86_64-apple-darwin',
    executable: 'codex',
  },
  'linux-arm64': {
    packageName: '@openai/codex-linux-arm64',
    triple: 'aarch64-unknown-linux-musl',
    executable: 'codex',
  },
  'linux-x64': {
    packageName: '@openai/codex-linux-x64',
    triple: 'x86_64-unknown-linux-musl',
    executable: 'codex',
  },
  'win32-arm64': {
    packageName: '@openai/codex-win32-arm64',
    triple: 'aarch64-pc-windows-msvc',
    executable: 'codex.exe',
  },
  'win32-x64': {
    packageName: '@openai/codex-win32-x64',
    triple: 'x86_64-pc-windows-msvc',
    executable: 'codex.exe',
  },
};

export interface CodexBinaryProbe {
  available: boolean;
  binaryPath: string | null;
  version: string | null;
  reason: string | null;
}

/** 探测顺序：环境变量 → 平台包 vendor → 应用根 node_modules → 系统 PATH */
function collectCandidates(): string[] {
  const candidates: string[] = [];
  if (process.env.ZSJZ_CODEX_BIN) candidates.push(process.env.ZSJZ_CODEX_BIN);

  const target = TARGETS[`${process.platform}-${process.arch}`];
  if (target) {
    // ee-bin 把主进程 bundle 成单文件 CJS，这里不能依赖 import.meta.url
    try {
      const packageJson = createRequire(__filename).resolve(`${target.packageName}/package.json`);
      candidates.push(join(dirname(packageJson), 'vendor', target.triple, 'bin', target.executable));
    } catch {
      // 平台包是 optionalDependency，缺失时继续尝试下面的候选
    }
    candidates.push(join(getBaseDir(), 'node_modules', target.packageName, 'vendor', target.triple, 'bin', target.executable));
  }

  const which = spawnSync(process.platform === 'win32' ? 'where' : 'which', ['codex'], {
    encoding: 'utf8',
    timeout: 3_000,
  });
  if (which.status === 0 && which.stdout.trim()) {
    candidates.push(which.stdout.trim().split(/\r?\n/u)[0]!);
  }
  return deduplicate(candidates);
}

/** 打包后 node_modules 在 app.asar 内，可执行文件必须走 asar.unpacked（builder.json 的 asarUnpack） */
export function unpackedAsarPath(value: string): string {
  return value.replace(/([/\\])app\.asar([/\\])/u, '$1app.asar.unpacked$2');
}

function deduplicate(values: string[]): string[] {
  return [...new Set(values.filter(Boolean))];
}

export async function locateCodexBinary(): Promise<string> {
  const failures: string[] = [];
  for (const lexical of collectCandidates()) {
    const candidate = unpackedAsarPath(lexical);
    try {
      await access(candidate, constants.X_OK);
      return await realpath(candidate);
    } catch (error) {
      failures.push(`${candidate}: ${error instanceof Error ? error.message : String(error)}`);
    }
  }
  throw new Error(
    `找不到可执行的 Codex 二进制，请设置 ZSJZ_CODEX_BIN。已检查 ${failures.length} 个候选路径。`,
  );
}

/** 供 ping 使用：任何失败都降级成 available:false + reason，不抛错 */
export async function probeCodexBinary(): Promise<CodexBinaryProbe> {
  try {
    const binaryPath = await locateCodexBinary();
    return { available: true, binaryPath, version: readCodexVersion(binaryPath), reason: null };
  } catch (error) {
    return {
      available: false,
      binaryPath: null,
      version: null,
      reason: error instanceof Error ? error.message : String(error),
    };
  }
}

export function readCodexVersion(binaryPath: string): string | null {
  const result = spawnSync(binaryPath, ['--version'], { encoding: 'utf8', timeout: 5_000 });
  return result.status === 0 ? result.stdout.trim() || null : null;
}