import {
  findAvailablePort,
  formatPortDecision,
  mapDevPortsToPortRange,
  normalizePort,
  reserveLinuxDevPortRange,
} from '../../../scripts/dev-stack-port-utils.mjs';

const agcDevHost = '127.0.0.1';
const legacyAgcDevPort = 3080;
const agcVitePortEnvKey = 'GENARRATIVE_AGC_VITE_PORT';

function readConfiguredAgcDevPort(env = process.env) {
  const rawPort = String(env[agcVitePortEnvKey] ?? '').trim();
  if (!rawPort) {
    return null;
  }

  const port = normalizePort(rawPort, -1);
  if (port < 1024) {
    throw new Error(`${agcVitePortEnvKey} 必须是 1024-65535 的有效端口`);
  }
  return port;
}

function createAgcDevEndpoint(port, portRange = null) {
  const url = `http://${agcDevHost}:${port}/`;
  return {
    host: agcDevHost,
    port,
    url,
    markerUrl: `${url}__agc_dev_server.json`,
    portRange,
  };
}

function readAgcDevEndpoint(env = process.env) {
  return createAgcDevEndpoint(
    readConfiguredAgcDevPort(env) ?? legacyAgcDevPort,
  );
}

async function resolveAgcDevEndpoint({
  env = process.env,
  platform = process.platform,
  strictConfigured = false,
  reservePortRange = reserveLinuxDevPortRange,
  findPort = findAvailablePort,
} = {}) {
  const configuredPort = readConfiguredAgcDevPort(env);
  let portRange = null;
  let preferredPort = configuredPort ?? legacyAgcDevPort;

  if (platform === 'linux') {
    const allocation = await reservePortRange({ env });
    if (!allocation?.range) {
      throw new Error('无法取得当前 Linux 用户的 dev 端口段');
    }
    portRange = allocation.range;
    const mappedAgcVitePort = mapDevPortsToPortRange(portRange)?.agcVitePort;
    if (!Number.isInteger(mappedAgcVitePort)) {
      throw new Error(
        `当前 Linux dev 端口段 ${portRange.label} 缺少 AGC Vite 槽位；请先迁移为至少 6 个端口且不与其它用户重叠的端口段`,
      );
    }
    if (configuredPort != null && configuredPort < mappedAgcVitePort) {
      throw new Error(
        `${agcVitePortEnvKey} ${configuredPort} 占用了 Linux dev 端口段 ${portRange.label} 的前五个服务槽位`,
      );
    }
    preferredPort = configuredPort ?? mappedAgcVitePort;
  }

  const port = await findPort({
    host: agcDevHost,
    preferredPort,
    portRange,
    strict: strictConfigured && configuredPort != null,
  });
  console.log(
    formatPortDecision({
      name: 'ai-game-creator-shell',
      host: agcDevHost,
      preferredPort,
      resolvedPort: port,
    }),
  );
  if (portRange) {
    console.log(`[ai-game-creator-shell] dev port-range: ${portRange.label}`);
  }

  return createAgcDevEndpoint(port, portRange);
}

function withAgcDevEndpointEnv(endpoint, env = process.env) {
  return {
    ...env,
    [agcVitePortEnvKey]: String(endpoint.port),
  };
}

export {
  agcDevHost,
  agcVitePortEnvKey,
  createAgcDevEndpoint,
  legacyAgcDevPort,
  readAgcDevEndpoint,
  readConfiguredAgcDevPort,
  resolveAgcDevEndpoint,
  withAgcDevEndpointEnv,
};