const MAX_LOG_ENTRIES = 300;
const logBuffer = [];
let snapshotProvider = null;
let browserDiagnosticsInstalled = false;

const safeError = (error) => {
  if (!error) return null;
  if (error instanceof Error) {
    return {
      name: error.name,
      message: error.message,
      stack: error.stack || null,
    };
  }
  return { message: String(error) };
};

const trimLogs = () => {
  if (logBuffer.length > MAX_LOG_ENTRIES) {
    logBuffer.splice(0, logBuffer.length - MAX_LOG_ENTRIES);
  }
};

export const airshipLog = (event, data = {}, level = 'info') => {
  const entry = {
    ts: new Date().toISOString(),
    level,
    event,
    ...data,
  };

  logBuffer.push(entry);
  trimLogs();

  const method = level === 'error' ? 'error' : level === 'warn' ? 'warn' : 'log';
  console[method]('[airship]', event, entry);
  return entry;
};

export const registerDebugSnapshot = (provider) => {
  snapshotProvider = typeof provider === 'function' ? provider : null;
};

export const getAirshipLogs = () => logBuffer.map((entry) => ({ ...entry }));

export const clearAirshipLogs = () => {
  logBuffer.length = 0;
};

export const installBrowserDiagnostics = () => {
  if (typeof window === 'undefined' || browserDiagnosticsInstalled) return;
  browserDiagnosticsInstalled = true;

  window.__AIRSHIP_LOGS__ = logBuffer;
  window.airshipDebug = {
    getLogs: getAirshipLogs,
    clearLogs: clearAirshipLogs,
    snapshot: () => {
      try {
        return snapshotProvider?.() ?? null;
      } catch (error) {
        airshipLog('debug:snapshot-error', { error: safeError(error) }, 'error');
        return null;
      }
    },
  };

  window.addEventListener('error', (event) => {
    airshipLog('runtime:error', {
      message: event.message || 'Unknown window error',
      source: event.filename || null,
      line: event.lineno || null,
      column: event.colno || null,
      error: safeError(event.error),
    }, 'error');
  });

  window.addEventListener('unhandledrejection', (event) => {
    airshipLog('runtime:unhandled-rejection', {
      error: safeError(event.reason),
    }, 'error');
  });

  airshipLog('diagnostics:installed', {
    userAgent: navigator?.userAgent || 'unknown',
  });
};

installBrowserDiagnostics();