using System.Diagnostics;
using System.Text;
using CVRManager.Models;

namespace CVRManager.Services;

public static class HookService
{
    static readonly TimeSpan Timeout = TimeSpan.FromMinutes(5);

    public static async Task<List<string>> RunEventAsync(
        IEnumerable<HookDef> hooks, InstallInfo install, string evt, string buildId, Action<string> log, CancellationToken ct)
    {
        var failures = new List<string>();
        foreach (var hook in hooks.Where(h => install.HookIds.Contains(h.Id) && h.Runs(evt)))
        {
            try
            {
                if (!await RunAsync(hook, install, buildId, log, ct)) failures.Add(hook.Name);
            }
            catch (OperationCanceledException) { throw; }
            catch (Exception e)
            {
                log($"[{hook.Name}] failed: {e.Message}");
                failures.Add(hook.Name);
            }
        }
        return failures;
    }

    public static async Task<bool> RunAsync(HookDef hook, InstallInfo install, string buildId, Action<string> log, CancellationToken ct)
    {
        var game = Paths.GameDir(install);
        if (!Directory.Exists(Path.Combine(game, "ChilloutVR_Data")))
        {
            log($"[{hook.Name}] skipped: the game files are not installed yet.");
            return true;
        }
        log($"[{hook.Name}] running for {install.Name}...");
        return await RunCommandAsync(hook, install, game, buildId, log, ct);
    }

    static async Task<bool> RunCommandAsync(HookDef hook, InstallInfo install, string game, string buildId, Action<string> log, CancellationToken ct)
    {
        if (string.IsNullOrWhiteSpace(hook.Command)) throw new InvalidOperationException("The hook has no command set.");
        string Expand(string s) => s
            .Replace("{game}", game, StringComparison.OrdinalIgnoreCase)
            .Replace("{install}", install.Name, StringComparison.OrdinalIgnoreCase)
            .Replace("{branch}", install.Branch, StringComparison.OrdinalIgnoreCase)
            .Replace("{build}", buildId, StringComparison.OrdinalIgnoreCase);

        var command = Expand(hook.Command.Trim());
        var args = SplitArgs(Expand(hook.Arguments)).ToList();
        var ext = Path.GetExtension(command).ToLowerInvariant();
        ProcessStartInfo psi;
        if (ext == ".ps1")
        {
            psi = new ProcessStartInfo(Path.Combine(Environment.SystemDirectory, "WindowsPowerShell", "v1.0", "powershell.exe"));
            foreach (var a in new[] { "-NoProfile", "-ExecutionPolicy", "Bypass", "-File", command }) psi.ArgumentList.Add(a);
        }
        else if (ext is ".bat" or ".cmd")
        {
            psi = new ProcessStartInfo("cmd.exe");
            psi.ArgumentList.Add("/c");
            psi.ArgumentList.Add(command);
        }
        else psi = new ProcessStartInfo(command);
        foreach (var a in args) psi.ArgumentList.Add(a);

        psi.Environment["CVR_GAME_DIR"] = game;
        psi.Environment["CVR_INSTALL_NAME"] = install.Name;
        psi.Environment["CVR_BRANCH"] = install.Branch;
        psi.Environment["CVR_BUILD"] = buildId;

        var code = await RunProcessAsync(psi, game, hook.Name, log, ct);
        if (code != 0) log($"[{hook.Name}] exited with code {code}");
        return code == 0;
    }

    static async Task<int> RunProcessAsync(ProcessStartInfo psi, string workDir, string label, Action<string> log, CancellationToken ct)
    {
        psi.WorkingDirectory = workDir;
        psi.UseShellExecute = false;
        psi.CreateNoWindow = true;
        psi.RedirectStandardOutput = true;
        psi.RedirectStandardError = true;
        psi.RedirectStandardInput = true;
        psi.StandardOutputEncoding = Encoding.UTF8;
        psi.StandardErrorEncoding = Encoding.UTF8;

        using var proc = new Process { StartInfo = psi };
        proc.OutputDataReceived += (_, e) => { if (!string.IsNullOrWhiteSpace(e.Data)) log($"[{label}] {e.Data.TrimEnd()}"); };
        proc.ErrorDataReceived += (_, e) => { if (!string.IsNullOrWhiteSpace(e.Data)) log($"[{label}] {e.Data.TrimEnd()}"); };
        proc.Start();
        proc.StandardInput.Close();
        proc.BeginOutputReadLine();
        proc.BeginErrorReadLine();

        using var cts = CancellationTokenSource.CreateLinkedTokenSource(ct);
        cts.CancelAfter(Timeout);
        try
        {
            await proc.WaitForExitAsync(cts.Token);
        }
        catch (OperationCanceledException)
        {
            try { proc.Kill(true); } catch { }
            if (ct.IsCancellationRequested) throw;
            throw new TimeoutException($"timed out after {Timeout.TotalMinutes:0} minutes");
        }
        proc.WaitForExit();
        return proc.ExitCode;
    }

    public static IEnumerable<string> SplitArgs(string s)
    {
        var sb = new StringBuilder();
        var quoted = false;
        foreach (var c in s)
        {
            if (c == '"') quoted = !quoted;
            else if (char.IsWhiteSpace(c) && !quoted)
            {
                if (sb.Length > 0) { yield return sb.ToString(); sb.Clear(); }
            }
            else sb.Append(c);
        }
        if (sb.Length > 0) yield return sb.ToString();
    }
}