using System.Diagnostics;
using Xunit;

namespace DevTool.Tests;

public sealed class HeadlessExecutionTests
{
    [Fact]
    public async Task HeadlessRun_JsonMode_EmitsVersionedEventsAndSummary()
    {
        var root = CreateTempProject("""
{
  "name": "headless-demo",
  "version": "0.1.0",
  "workflows": [
    {
      "id": "build",
      "label": "Build",
      "description": "Build",
      "group": "Build",
      "dependsOn": [],
      "steps": [
        {
          "id": "s1",
          "label": "dotnet --version",
          "command": "dotnet",
          "args": ["--version"],
          "workingDir": ".",
          "requires": []
        }
      ]
    }
  ]
}
""");

        var result = await RunSdtAsync(["run", "build", "--json", "--project-root", root]);

        Assert.Equal(0, result.ExitCode);
        Assert.Contains($"\"run_event_version\":\"{Sdt.Core.HeadlessExecutionService.ContractVersion}\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"event_type\":\"WorkflowStarted\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"category\":\"workflow\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"success\":true", result.StdOut, StringComparison.Ordinal);
    }

    [Fact]
    public async Task HeadlessRun_NonInteractive_MissingPrereq_UsesDeterministicExitCode()
    {
        var root = CreateTempProject("""
{
  "name": "headless-demo",
  "version": "0.1.0",
  "workflows": [
    {
      "id": "build",
      "label": "Build",
      "description": "Build",
      "group": "Build",
      "dependsOn": [],
      "steps": [
        {
          "id": "s1",
          "label": "dotnet --version",
          "command": "dotnet",
          "args": ["--version"],
          "workingDir": ".",
          "requires": [
            { "tool": "definitely-missing-tool", "installPolicy": "Prompt" }
          ]
        }
      ]
    }
  ]
}
""");

        var result = await RunSdtAsync(["run", "build", "--json", "--project-root", root, "--non-interactive"]);

        Assert.Equal(14, result.ExitCode);
        Assert.Contains("\"stopReason\":\"UserDeclined\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"exactFixCommand\"", result.StdOut, StringComparison.Ordinal);
    }

    [Fact]
    public async Task HeadlessDebug_JsonMode_EmitsDebugSummary()
    {
        var root = CreateTempProject("""
{
  "name": "headless-demo",
  "version": "0.1.0",
  "workflows": [],
  "debug": {
    "profiles": [
      {
        "id": "d1",
        "label": "Dotnet Info",
        "type": "dotnet",
        "command": "dotnet",
        "args": ["--info"],
        "workingDir": ".",
        "env": {},
        "requires": []
      }
    ]
  }
}
""");

        var result = await RunSdtAsync(["debug", "d1", "--json", "--project-root", root]);

        Assert.Equal(0, result.ExitCode);
        Assert.Contains("\"category\":\"debug\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"event_type\":\"DebugStarted\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"success\":true", result.StdOut, StringComparison.Ordinal);
    }

    [Fact]
    public async Task HeadlessRun_CommandFailure_MapsToDeterministicExitCode()
    {
        var root = CreateTempProject("""
{
  "name": "headless-demo",
  "version": "0.1.0",
  "workflows": [
    {
      "id": "build",
      "label": "Build",
      "description": "Build",
      "group": "Build",
      "dependsOn": [],
      "steps": [
        {
          "id": "s1",
          "label": "dotnet bad command",
          "command": "dotnet",
          "args": ["__definitely_invalid_command__"],
          "workingDir": ".",
          "requires": []
        }
      ]
    }
  ]
}
""");

        var result = await RunSdtAsync(["run", "build", "--json", "--project-root", root]);

        Assert.Equal(12, result.ExitCode);
        Assert.Contains("\"stopReason\":\"CommandFailed\"", result.StdOut, StringComparison.Ordinal);
        Assert.Contains("\"retryInstruction\"", result.StdOut, StringComparison.Ordinal);
    }

    [Fact]
    public async Task HeadlessRun_AllowsGuidedAliasSelection()
    {
        var root = CreateTempProject("""
{
  "name": "headless-demo",
  "version": "0.1.0",
  "workflows": [
    {
      "id": "build",
      "label": "Build project",
      "guidedName": "build app",
      "aliases": ["app", "compile"],
      "description": "Build",
      "group": "Build",
      "dependsOn": [],
      "steps": [
        {
          "id": "s1",
          "label": "dotnet --version",
          "command": "dotnet",
          "args": ["--version"],
          "workingDir": ".",
          "requires": []
        }
      ]
    }
  ]
}
""");

        var result = await RunSdtAsync(["run", "app", "--json", "--project-root", root]);

        Assert.Equal(0, result.ExitCode);
        Assert.Contains("\"success\":true", result.StdOut, StringComparison.Ordinal);
    }

    private static async Task<(int ExitCode, string StdOut, string StdErr)> RunSdtAsync(IReadOnlyList<string> args)
    {
        var exe = Path.Combine(AppContext.BaseDirectory, OperatingSystem.IsWindows() ? "sdt.exe" : "sdt");
        if (!File.Exists(exe))
            throw new InvalidOperationException($"Could not find test runtime executable: {exe}");

        var psi = new ProcessStartInfo
        {
            FileName = exe,
            RedirectStandardOutput = true,
            RedirectStandardError = true,
            UseShellExecute = false,
            CreateNoWindow = true,
        };

        foreach (var arg in args)
            psi.ArgumentList.Add(arg);

        using var process = new Process { StartInfo = psi };
        process.Start();
        var stdout = await process.StandardOutput.ReadToEndAsync();
        var stderr = await process.StandardError.ReadToEndAsync();
        await process.WaitForExitAsync();
        return (process.ExitCode, stdout, stderr);
    }

    private static string CreateTempProject(string devtoolJson)
    {
        var root = Path.Combine(Path.GetTempPath(), "sdt-headless-" + Guid.NewGuid().ToString("N"));
        Directory.CreateDirectory(root);
        File.WriteAllText(Path.Combine(root, "sdtconfig-headless.json"), devtoolJson);
        return root;
    }
}