// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

import 'dart:async';
import 'dart:io';

import 'package:io/ansi.dart';
import 'package:logging/logging.dart';

typedef LogWriter =
    void Function(
      Level level,
      String message, {
      String? error,
      String? loggerName,
      String? stackTrace,
    });

var _verbose = false;
StreamSubscription<LogRecord>? _subscription;

void configureLogWriter(bool verbose, {LogWriter? customLogWriter}) {
  _verbose = verbose;
  _logWriter = customLogWriter ?? _logWriter;
  Logger.root.level = verbose ? Level.ALL : Level.INFO;
  _subscription ??= Logger.root.onRecord.listen((event) {
    logWriter(
      event.level,
      event.message,
      error: event.error?.toString(),
      loggerName: event.loggerName,
      stackTrace: event.stackTrace?.toString(),
    );
  });
}

// ignore: prefer_function_declarations_over_variables
LogWriter _logWriter =
    (level, message, {String? error, String? loggerName, String? stackTrace}) {
      // Erases the previous line
      if (!_verbose) stdout.write('\x1b[2K\r');
      final log = formatLog(
        level,
        message,
        error: error,
        loggerName: loggerName,
        stackTrace: stackTrace,
        withColors: true,
      );

      if (level >= Level.INFO || _verbose) {
        stdout.write(log);
        // Prevent multiline logs and > info messages from being erased.
        if (level > Level.INFO ||
            _verbose ||
            (log.contains('\n') && !log.endsWith('\n'))) {
          stdout.writeln('');
        }
      }
    };

LogWriter get logWriter => _logWriter;

/// Colors the message and writes it to stdout.
String formatLog(
  Level level,
  String message, {
  bool? withColors,
  String? error,
  String? loggerName,
  String? stackTrace,
}) {
  withColors ??= false;
  final buffer = StringBuffer(message);
  if (error != null) {
    buffer.writeln(error);
  }

  if (_verbose && stackTrace != null) {
    buffer.writeln(stackTrace);
  }

  var formattedLevel = '[$level]';
  if (withColors) {
    AnsiCode color;
    if (level < Level.WARNING) {
      color = cyan;
    } else if (level < Level.SEVERE) {
      color = yellow;
    } else {
      color = red;
    }
    formattedLevel = color.wrap(formattedLevel) ?? formattedLevel;
  }

  final loggerNameOutput =
      (loggerName != null && (_verbose || loggerName.contains(' ')))
      ? ' $loggerName:'
      : '';
  return '$formattedLevel$loggerNameOutput $buffer';
}