import { registerOpenCodeProxy } from './proxy.js';

export const createServerUtilsRuntime = (dependencies) => {
  const {
    fs,
    os,
    path,
    process,
    openCodeReadyGraceMs,
    longRequestTimeoutMs,
    getRuntime,
    getOpenCodeAuthHeaders,
    buildOpenCodeUrl,
    ensureOpenCodeApiPrefix,
    getUiNotificationClients,
    getOpenCodePort,
    setOpenCodePortState,
    syncToHmrState,
    markOpenCodeNotReady,
    setOpenCodeNotReadySince,
    clearLastOpenCodeError,
    getLoginShellPath,
  } = dependencies;

  const setOpenCodePort = (port) => {
    if (!Number.isFinite(port) || port <= 0) {
      return;
    }

    const numericPort = Math.trunc(port);
    const currentPort = getOpenCodePort();
    const portChanged = currentPort !== numericPort;

    if (portChanged || currentPort === null) {
      setOpenCodePortState(numericPort);
      syncToHmrState();
      console.log(`Detected OpenCode port: ${numericPort}`);

      if (portChanged) {
        markOpenCodeNotReady();
      }
      setOpenCodeNotReadySince(Date.now());
    }

    clearLastOpenCodeError();
  };

  const pathLooksUserConfigured = (value) => {
    if (typeof value !== 'string' || !value) {
      return false;
    }

    const home = os.homedir();
    return value.split(path.delimiter).some((segment) => (
      segment.startsWith(home + path.sep)
      || segment === home
      || segment.startsWith('/opt/homebrew/')
      || segment.startsWith('/opt/pkg/')
      || segment.startsWith('/opt/pmk/')
    ));
  };

  const waitForOpenCodePort = async (timeoutMs = 15000) => {
    if (getOpenCodePort() !== null) {
      return getOpenCodePort();
    }

    const deadline = Date.now() + timeoutMs;
    while (Date.now() < deadline) {
      await new Promise((resolve) => setTimeout(resolve, 50));
      if (getOpenCodePort() !== null) {
        return getOpenCodePort();
      }
    }

    throw new Error('Timed out waiting for OpenCode port');
  };

  const buildAugmentedPath = () => {
    const home = os.homedir();
    const currentPath = process.env.PATH || '';
    const loginShellPath = getLoginShellPath();
    const currentPathLooksUserConfigured = pathLooksUserConfigured(currentPath);
    const primaryPath = currentPathLooksUserConfigured ? currentPath : loginShellPath;
    const fallbackPath = currentPathLooksUserConfigured ? loginShellPath : currentPath;
    const seen = new Set();
    const augmented = [];

    const addSegments = (value) => {
      if (typeof value !== 'string' || !value) {
        return;
      }
      for (const segment of value.split(path.delimiter)) {
        if (segment && !seen.has(segment)) {
          seen.add(segment);
          augmented.push(segment);
        }
      }
    };

    addSegments(primaryPath);
    addSegments(fallbackPath);

    return augmented.join(path.delimiter);
  };

  const buildManagedOpenCodePath = () => {
    const currentPath = process.env.PATH || '';
    if (pathLooksUserConfigured(currentPath)) {
      return currentPath;
    }

    return getLoginShellPath() || currentPath;
  };

  const parseSseDataPayload = (block) => {
    if (!block || typeof block !== 'string') {
      return null;
    }
    const dataLines = block
      .split('\n')
      .filter((line) => line.startsWith('data:'))
      .map((line) => line.slice(5).replace(/^\s/, ''));

    if (dataLines.length === 0) {
      return null;
    }

    const payloadText = dataLines.join('\n').trim();
    if (!payloadText) {
      return null;
    }

    try {
      const parsed = JSON.parse(payloadText);
      if (
        parsed &&
        typeof parsed === 'object' &&
        typeof parsed.payload === 'object' &&
        parsed.payload !== null
      ) {
        return parsed.payload;
      }
      return parsed;
    } catch {
      return null;
    }
  };

  const fetchArraySnapshot = async (route, invalidMessage) => {
    if (!getOpenCodePort()) {
      throw new Error('OpenCode port is not available');
    }

    const response = await fetch(buildOpenCodeUrl(route), {
      method: 'GET',
      headers: { Accept: 'application/json', ...getOpenCodeAuthHeaders() },
    });

    if (!response.ok) {
      throw new Error(`Failed to fetch ${invalidMessage} (status ${response.status})`);
    }

    const payload = await response.json().catch(() => null);
    if (!Array.isArray(payload)) {
      throw new Error(`Invalid ${invalidMessage} payload from OpenCode`);
    }
    return payload;
  };

  const fetchAgentsSnapshot = () => fetchArraySnapshot('/agent', 'agents snapshot');
  const fetchProvidersSnapshot = () => fetchArraySnapshot('/provider', 'providers snapshot');
  const fetchModelsSnapshot = () => fetchArraySnapshot('/model', 'models snapshot');

  const setupProxy = (app) => {
    registerOpenCodeProxy(app, {
      fs,
      os,
      path,
      OPEN_CODE_READY_GRACE_MS: openCodeReadyGraceMs,
      LONG_REQUEST_TIMEOUT_MS: longRequestTimeoutMs,
      getRuntime,
      getOpenCodeAuthHeaders,
      buildOpenCodeUrl,
      ensureOpenCodeApiPrefix,
      getUiNotificationClients,
    });
  };

  return {
    setOpenCodePort,
    waitForOpenCodePort,
    buildAugmentedPath,
    buildManagedOpenCodePath,
    parseSseDataPayload,
    fetchAgentsSnapshot,
    fetchProvidersSnapshot,
    fetchModelsSnapshot,
    setupProxy,
  };
};