using System.Text;
using System.Text.Json;
using Recordingtest.DiffReporter;

namespace Recordingtest.DiffReporter.Cli;

public static class Program
{
    public static int Main(string[] args)
    {
        try
        {
            string? approved = null, received = null, outDir = null;
            for (int i = 0; i < args.Length; i++)
            {
                switch (args[i])
                {
                    case "--approved": approved = args[++i]; break;
                    case "--received": received = args[++i]; break;
                    case "--out": outDir = args[++i]; break;
                }
            }
            if (approved is null || received is null || outDir is null)
            {
                Console.Error.WriteLine("Usage: --approved <path> --received <path> --out <dir>");
                return 2;
            }

            Directory.CreateDirectory(outDir);
            DiffResult result;
            try
            {
                result = Differ.Compare(approved, received);
            }
            catch (IOException ex)
            {
                Console.Error.WriteLine("I/O error: " + ex.Message);
                return 2;
            }
            catch (UnauthorizedAccessException ex)
            {
                Console.Error.WriteLine("I/O error: " + ex.Message);
                return 2;
            }

            var jsonOpts = new JsonSerializerOptions
            {
                PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                WriteIndented = true
            };
            File.WriteAllText(Path.Combine(outDir, "diff.json"),
                JsonSerializer.Serialize(result, jsonOpts), Encoding.UTF8);
            File.WriteAllText(Path.Combine(outDir, "diff.md"),
                RenderMarkdown(result), Encoding.UTF8);

            if (result.Identical)
            {
                Console.Out.WriteLine("identical");
                return 0;
            }
            Console.Out.WriteLine($"diff: +{result.Summary.Added} -{result.Summary.Removed} ~{result.Summary.Changed} in {result.File}");
            return 1;
        }
        catch (IOException ex)
        {
            Console.Error.WriteLine("I/O error: " + ex.Message);
            return 2;
        }
    }

    private static string RenderMarkdown(DiffResult r)
    {
        var sb = new StringBuilder();
        sb.AppendLine($"# Diff: {r.File}");
        sb.AppendLine();
        sb.AppendLine($"Identical: **{r.Identical}**");
        sb.AppendLine();
        sb.AppendLine("| Added | Removed | Changed |");
        sb.AppendLine("|------:|--------:|--------:|");
        sb.AppendLine($"| {r.Summary.Added} | {r.Summary.Removed} | {r.Summary.Changed} |");
        sb.AppendLine();
        if (r.Hunks.Count > 0)
        {
            sb.AppendLine("## Hunks");
            sb.AppendLine();
            sb.AppendLine("| # | LineOrOffset | Kind | Before | After |");
            sb.AppendLine("|--:|-------------:|------|--------|-------|");
            for (int i = 0; i < r.Hunks.Count; i++)
            {
                var h = r.Hunks[i];
                sb.AppendLine($"| {i} | {h.LineOrOffset} | {h.Kind} | {Escape(h.Before)} | {Escape(h.After)} |");
            }
        }
        return sb.ToString();
    }

    private static string Escape(string s) =>
        s.Replace("|", "\\|").Replace("\r", "").Replace("\n", "\\n");
}