using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;

namespace Character_Builder;

/// <summary>Reads/writes a composition as a human-readable .md file.</summary>
public static class BuildMd
{
    public static void Save(string path, BuildDefinition b)
    {
        var sb = new StringBuilder();
        sb.AppendLine($"# Character Build — {b.Name}");
        sb.AppendLine();
        sb.AppendLine("> Saved by Character_Builder. Layers are composited: body + head(expression) + hair tint + accessories.");
        sb.AppendLine("> Coordinate convention (for the Dansori app): stage 520x680. Each layer image is drawn Height=680 (Stretch=Uniform),");
        sb.AppendLine("> centered in the stage, scaled about its center by 'scale', then translated by (x, y) pixels. transform = x, y, scale.");
        sb.AppendLine("> The app can either reuse these transforms directly (same convention) or re-run alpha neck-alignment and treat these as deltas.");
        sb.AppendLine();
        sb.AppendLine($"name: {b.Name}");
        sb.AppendLine($"character: {b.Character}");
        sb.AppendLine($"body: {b.BodyFile}");
        sb.AppendLine($"body.transform: {F(b.BodyOffsetX)}, {F(b.BodyOffsetY)}, {F(b.BodyScale)}");
        sb.AppendLine($"head: {b.HeadFile}");
        sb.AppendLine($"expression: {b.ExpressionFile}");
        sb.AppendLine($"hairmask: {b.HairmaskFile}");
        sb.AppendLine($"hairColor: {b.HairColor}");
        sb.AppendLine($"head.transform: {F(b.HeadOffsetX)}, {F(b.HeadOffsetY)}, {F(b.HeadScale)}");
        sb.AppendLine();
        sb.AppendLine("## accessories");
        foreach (var a in b.Accessories)
            sb.AppendLine($"- {a.FileName} | {F(a.OffsetX)}, {F(a.OffsetY)}, {F(a.Scale)}");
        File.WriteAllText(path, sb.ToString(), new UTF8Encoding(false));
    }

    public static BuildDefinition Load(string path)
    {
        var b = new BuildDefinition();
        bool inAcc = false;
        foreach (var raw in File.ReadAllLines(path))
        {
            var line = raw.Trim();
            if (line.Length == 0) continue;
            if (line.StartsWith("## accessories", StringComparison.OrdinalIgnoreCase)) { inAcc = true; continue; }
            if (line.StartsWith("#")) continue;
            if (line.StartsWith(">")) continue;

            if (inAcc && line.StartsWith("-"))
            {
                var body = line.TrimStart('-', ' ');
                var parts = body.Split('|');
                var a = new AccessoryLayer { FileName = parts[0].Trim() };
                if (parts.Length > 1) ApplyTransform(parts[1], (x, y, s) => { a.OffsetX = x; a.OffsetY = y; a.Scale = s; });
                if (!string.IsNullOrEmpty(a.FileName)) b.Accessories.Add(a);
                continue;
            }

            int c = line.IndexOf(':');
            if (c < 0) continue;
            var key = line.Substring(0, c).Trim().ToLowerInvariant();
            var val = line.Substring(c + 1).Trim();
            switch (key)
            {
                case "name": b.Name = val; break;
                case "character": b.Character = val; break;
                case "body": b.BodyFile = Empty(val); break;
                case "body.transform":
                    ApplyTransform(val, (x, y, s) => { b.BodyOffsetX = x; b.BodyOffsetY = y; b.BodyScale = s; });
                    break;
                case "head": b.HeadFile = Empty(val); break;
                case "expression": b.ExpressionFile = Empty(val); break;
                case "hairmask": b.HairmaskFile = Empty(val); break;
                case "haircolor": b.HairColor = Empty(val); break;
                case "head.transform":
                    ApplyTransform(val, (x, y, s) => { b.HeadOffsetX = x; b.HeadOffsetY = y; b.HeadScale = s; });
                    break;
            }
        }
        return b;
    }

    private static string? Empty(string v) => string.IsNullOrWhiteSpace(v) ? null : v;

    private static void ApplyTransform(string s, Action<double, double, double> set)
    {
        var t = s.Split(',');
        double x = t.Length > 0 ? D(t[0]) : 0;
        double y = t.Length > 1 ? D(t[1]) : 0;
        double sc = t.Length > 2 ? D(t[2]) : 1;
        set(x, y, sc);
    }

    private static double D(string s) =>
        double.TryParse(s.Trim(), NumberStyles.Any, CultureInfo.InvariantCulture, out var v) ? v : 0;

    private static string F(double v) => v.ToString("0.###", CultureInfo.InvariantCulture);
}