import 'dart:developer' as developer;

import 'package:flutter/foundation.dart' show debugPrint, kDebugMode;
import 'package:nhance_app_pwa/config/environment.dart';

String _timestamp() => DateTime.now().toIso8601String();

enum LogLevel { debug, info, warning, error }

class LoggerConfig {
  static bool enabled = true;

  /// Logs below this level are dropped ([logDebug] when this is [LogLevel.info]).
  static LogLevel minLevel = LogLevel.info;

  // Stack parsing is expensive; keep it disabled unless specifically needed.
  static bool includeCallerFromStack = false;
}

String? _inferCallerTag(StackTrace stackTrace) {
  final lines = stackTrace.toString().split('\n');

  // Find the first stack frame that is not inside this logger file.
  for (final line in lines) {
    if (line.contains('logger.dart')) continue;

    // Example formats vary by platform; we try to extract a readable symbol name.
    // Common patterns:
    //  - "#0      foo.bar (package:.../file.dart:12:3)"
    //  - "foo.bar (file.dart:12:3)"
    final match = RegExp(r'(?:(?:#\d+)\s+)?([A-Za-z0-9_$.<>]+)\s*\(').firstMatch(line);
    final symbol = match?.group(1);
    if (symbol != null && symbol.trim().isNotEmpty) return symbol.trim();
  }
  return null;
}

void _log(
  LogLevel level,
  Object? message, {
  String? tag,
  Object? error,
  StackTrace? stackTrace,
}) {
  if (!LoggerConfig.enabled) return;

  // Verbose minimum: UAT (all modes), or local Dev when using a debug Flutter build.
  final LogLevel effectiveMinLevel = switch (Environment.flavor) {
    Flavor.uat => LogLevel.debug,
    Flavor.dev when kDebugMode => LogLevel.debug,
    _ => LoggerConfig.minLevel,
  };
  if (level.index < effectiveMinLevel.index) return;

  // Debug lines: debug Flutter build (typical `flutter run`), or any UAT build.
  if (level == LogLevel.debug && !kDebugMode && Environment.flavor != Flavor.uat) {
    return;
  }

  final inferredTag = tag ??
      (LoggerConfig.includeCallerFromStack
          ? _inferCallerTag(stackTrace ?? StackTrace.current)
          : null);
  final levelName = level.name.toUpperCase();
  final fullMessage = '[${_timestamp()}] [$levelName]${inferredTag != null ? ' [$inferredTag]' : ''} $message';

  developer.log(
    fullMessage,
    name: inferredTag ?? 'app',
    error: error,
    stackTrace: stackTrace,
  );

  // `developer.log` is easy to miss in release/profile (IDE filters, logcat tags).
  // UAT: always mirror to stdout-style logging so `adb logcat`, Xcode, and web consoles show lines.
  // Debug builds: mirror too for parity with `print` during local runs.
  if (Environment.flavor == Flavor.uat || kDebugMode) {
    debugPrint(fullMessage);
    if (Environment.flavor == Flavor.uat && (error != null || stackTrace != null)) {
      debugPrint('$error\n$stackTrace');
    }
  }
}

/// **Dev + localhost:** shown when you use `flutter run` (debug mode); not in `flutter run --release`.
/// **UAT:** also emitted in profile/release (verbose).
/// **Prod / Prod1:** debug Flutter build only; in release/profile use [logInfo] or `print`.
void logDebug(Object? message, {String? tag}) {
  _log(LogLevel.debug, message, tag: tag);
}

void logInfo(Object? message, {String? tag}) {
  _log(LogLevel.info, message, tag: tag);
}

void logWarning(Object? message, {String? tag}) {
  _log(LogLevel.warning, message, tag: tag);
}

void logError(Object? message, {String? tag, Object? error, StackTrace? stackTrace}) {
  _log(LogLevel.error, message, tag: tag, error: error, stackTrace: stackTrace);
}