using System;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading;

internal static class TestFixture
{
    private static int Main(string[] args)
    {
        string exe = Path.GetFileName(Environment.GetCommandLineArgs()[0]).ToLowerInvariant();
        if (exe == "adb.exe")
        {
            return RunAdb(args);
        }
        if (exe == "scrcpy.exe")
        {
            return RunScrcpy(args);
        }
        Console.Error.WriteLine("Unexpected fixture executable name.");
        return 90;
    }

    private static int RunAdb(string[] args)
    {
        Log("ADB " + string.Join(" ", args));
        string mode = Environment.GetEnvironmentVariable("APU_FIXTURE_MODE") ?? "single";

        if (args.SequenceEqual(new[] { "version" }))
        {
            Console.WriteLine("Android Debug Bridge version 1.0.41");
            return 0;
        }

        if (args.SequenceEqual(new[] { "mdns", "services" }))
        {
            if (mode == "none")
            {
                return 0;
            }
            if (mode == "pair")
            {
                Console.WriteLine("adb-EXAMPLE-PAIR _adb-tls-pairing._tcp 192.0.2.10:37123");
                return 0;
            }
            Console.WriteLine("adb-EXAMPLE-A _adb-tls-connect._tcp 192.0.2.10:12345");
            if (mode == "multi")
            {
                Console.WriteLine("adb-EXAMPLE-B _adb-tls-connect._tcp 198.51.100.20:23456");
            }
            return 0;
        }

        if (args.Length == 2 && args[0] == "connect")
        {
            Console.WriteLine("connected to " + args[1]);
            return 0;
        }

        if (args.Length == 2 && args[0] == "pair")
        {
            if (!string.IsNullOrEmpty(Environment.GetEnvironmentVariable("APU_PAIRING_CODE")) ||
                !string.IsNullOrEmpty(Environment.GetEnvironmentVariable("AWC_PAIRING_CODE")))
            {
                Console.Error.WriteLine("Pairing code leaked into the ADB child environment.");
                return 94;
            }

            string expectedCode = Environment.GetEnvironmentVariable("APU_FIXTURE_EXPECT_PAIRING_CODE");
            if (!string.IsNullOrWhiteSpace(expectedCode))
            {
                string suppliedCode = Console.In.ReadLine();
                if (!string.Equals(suppliedCode, expectedCode, StringComparison.Ordinal))
                {
                    Console.Error.WriteLine("Pairing code was not received through standard input.");
                    return 93;
                }
            }
            Console.WriteLine("Successfully paired to " + args[1]);
            return 0;
        }

        if (args.Length == 3 && args[0] == "-s" && args[2] == "get-state")
        {
            Console.WriteLine("device");
            return 0;
        }

        if (args.SequenceEqual(new[] { "devices" }))
        {
            Console.WriteLine("List of devices attached");
            Console.WriteLine("192.0.2.10:12345\tdevice");
            if (mode == "alias")
            {
                Console.WriteLine("adb-EXAMPLE-A._adb-tls-connect._tcp\tdevice");
            }
            return 0;
        }

        if (args.Length > 0 && args[0] == "shell")
        {
            Console.Error.WriteLine("Bare adb shell is forbidden by the fixture.");
            return 91;
        }

        Console.Error.WriteLine("Unexpected adb arguments: " + string.Join(" ", args));
        return 92;
    }

    private static int RunScrcpy(string[] args)
    {
        if (args.SequenceEqual(new[] { "--version" }))
        {
            Console.WriteLine("scrcpy 4.0 <https://github.com/Genymobile/scrcpy>");
            return 0;
        }

        Log("SCRCPY " + string.Join(" ", args));
        int sleepMs;
        if (int.TryParse(Environment.GetEnvironmentVariable("APU_FIXTURE_SCRCPY_SLEEP_MS"), out sleepMs) && sleepMs > 0)
        {
            Thread.Sleep(sleepMs);
        }

        int exitCode;
        if (int.TryParse(Environment.GetEnvironmentVariable("APU_FIXTURE_SCRCPY_EXIT"), out exitCode))
        {
            return exitCode;
        }
        return 0;
    }

    private static void Log(string line)
    {
        string path = Environment.GetEnvironmentVariable("APU_FIXTURE_LOG");
        if (string.IsNullOrWhiteSpace(path))
        {
            return;
        }

        byte[] bytes = Encoding.UTF8.GetBytes(line + Environment.NewLine);
        for (int attempt = 0; attempt < 20; attempt++)
        {
            try
            {
                using (var stream = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write, FileShare.ReadWrite))
                {
                    stream.Seek(0, SeekOrigin.End);
                    stream.Write(bytes, 0, bytes.Length);
                    stream.Flush();
                }
                return;
            }
            catch (IOException)
            {
                Thread.Sleep(25);
            }
        }
        throw new IOException("Fixture invocation log remained locked.");
    }
}