using System;
using System.Diagnostics;
using System.IO;
using System.Management.Automation;
using SQLite;

namespace PowershellModule.Git;

[Cmdlet(VerbsCommon.New, Noun)]
public class NewGitRepoCommand : PSCmdlet
{
	private const string Noun = "GitRepo";

	[Parameter(
		Mandatory = true,
		Position = 0,
		ValueFromPipeline = true,
		HelpMessage = "Reference name for the repo")]
	public string Name { get; set; }

	public NewGitRepoCommand()
	{
		Console.WriteLine($"{nameof(NewGitRepoCommand)} init");
		var gm = GitManager.Instance;
	}

	protected override void BeginProcessing()
	{
		//using var conn = new SQLiteConnection("./test.db");

		var pwd = this.SessionState.Path.CurrentLocation.Path;
		WriteObject("Checking if current directory is a git repository...");

		var repoFolfder = IsGitRepo(pwd);


		base.BeginProcessing();
	}

	private ParsedGitFolderDetails? IsGitRepo(string path)
	{
		var ps = new ProcessStartInfo("git",
			["rev-parse", "--show-toplevel"])
		{
			RedirectStandardOutput = true,
			RedirectStandardError = true,
			WorkingDirectory = path
		};

		// If the user doesn't have git on their path, this will throw an exception that I don't have to do anything
		// special with, it'll be unhandled and powershell will handle it
		var gitProcess = Process.Start(ps);

		// This probably shouldn't be possible? Not really sure of the conditions where the process could be started
		// but return null, but I'm going to consider that unrecoverable error territory
		if (gitProcess is null)
		{
			throw new Exception("git failed to start");
		}

		gitProcess.WaitForExit();

		if (!gitProcess.StandardOutput.EndOfStream)
		{
			var directory = gitProcess.StandardOutput.ReadToEnd();
			// Gotta trim what we get as it might already have a newline character at the end
			var dirInfo = new DirectoryInfo(directory.Trim());

			var repoFolderInfo = new ParsedGitFolderDetails
			{
				Directory = dirInfo.FullName,
				Folder = dirInfo.Name,
			};

			return repoFolderInfo;
		}

		if (!gitProcess.StandardError.EndOfStream)
		{
			var errorAsException = new Exception(gitProcess.StandardError.ReadToEnd());
			WriteError(new ErrorRecord(errorAsException, "git-not-found", ErrorCategory.FromStdErr, null));
		}

		return null;
	}

	/// <summary>
	/// The directory details of the directory returned from git rev-parse --show-toplevel
	/// </summary>
	private class ParsedGitFolderDetails
	{
		/// <summary>
		/// The full path to the top level folder containing a git repository
		/// </summary>
		public string Directory { get; set; } = null!;

		/// <summary>
		/// The last folder name of the directory
		/// </summary>
		public string Folder { get; set; } = null!;
	}
}

[Cmdlet(VerbsCommon.Set, Noun)]
public class SetGitRepoCommand : PSCmdlet
{
	private const string Noun = "GitRepo";

	public SetGitRepoCommand()
	{
		Console.WriteLine($"{nameof(NewGitRepoCommand)} init");
		var a = GitManager.Instance;
	}

	protected override void BeginProcessing()
	{
		base.BeginProcessing();
	}
}

// TODO: better name for this
public class GitManager
{
	private static readonly Lazy<GitManager> GitManagerInstance = new(() => new GitManager());
	public static GitManager Instance => GitManagerInstance.Value;

	private GitManager()
	{
		Console.WriteLine($"{nameof(GitManager)} init");
	}
}