// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using Microsoft.Extensions.Logging;

namespace Microsoft.DotNet.Watch;

internal sealed class ConsoleInputReader(IConsole console, LogLevel logLevel, bool suppressEmojis)
{
    private readonly object _writeLock = new();

    public async Task<ConsoleKeyInfo> GetKeyAsync(string prompt, Func<ConsoleKeyInfo, bool> validateInput, CancellationToken cancellationToken)
    {
        if (logLevel > LogLevel.Information)
        {
            return new ConsoleKeyInfo('\u001b', ConsoleKey.Escape, shift: false, alt: false, control: false);
        }

        var questionMark = suppressEmojis ? "?" : "❔";
        while (true)
        {
            // Start listening to the key before printing the prompt to avoid race condition
            // in tests that wait for the prompt before sending the key press.
            var tcs = new TaskCompletionSource<ConsoleKeyInfo>(TaskCreationOptions.RunContinuationsAsynchronously);
            console.KeyPressed += KeyPressed;

            WriteLine($"  {questionMark} {prompt}");

            lock (_writeLock)
            {
                console.ForegroundColor = ConsoleColor.DarkGray;
                console.Out.Write($"  {questionMark} ");
                console.ResetColor();
            }

            try
            {
                return await tcs.Task.WaitAsync(cancellationToken);
            }
            catch (ArgumentException)
            {
                // Prompt again for valid input
            }
            finally
            {
                console.KeyPressed -= KeyPressed;
            }

            void KeyPressed(ConsoleKeyInfo key)
            {
                var keyDisplay = GetDisplayString(key);
                if (validateInput(key))
                {
                    WriteLine(keyDisplay);
                    tcs.TrySetResult(key);
                }
                else
                {
                    WriteLine(keyDisplay, ConsoleColor.DarkRed);
                    tcs.TrySetException(new ArgumentException($"Invalid key '{keyDisplay}' entered."));
                }
            }

            static string GetDisplayString(ConsoleKeyInfo key)
            {
                var keyDisplay = (key.Modifiers == ConsoleModifiers.None) ? key.KeyChar.ToString() : key.Key.ToString();

                if (key.Modifiers.HasFlag(ConsoleModifiers.Alt))
                {
                    keyDisplay = "Alt+" + keyDisplay;
                }

                if (key.Modifiers.HasFlag(ConsoleModifiers.Shift))
                {
                    keyDisplay = "Shift+" + keyDisplay;
                }

                if (key.Modifiers.HasFlag(ConsoleModifiers.Control))
                {
                    keyDisplay = "Ctrl+" + keyDisplay;
                }

                return keyDisplay;
            }
        }

        void WriteLine(string message, ConsoleColor color = ConsoleColor.DarkGray)
        {
            lock (_writeLock)
            {
                console.ForegroundColor = color;
                console.Out.WriteLine(message);
                console.ResetColor();
            }
        }
    }
}