using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using Luneraria.View;
using Newtonsoft.Json.Linq;
using UnityEditor;
using UnityEngine;

namespace Luneraria.EditorTools
{
    /// <summary>
    /// Creates the shared materials (U2B) from the Godot material library
    /// (scripts/luneraria/view/lune_materials.gd), the baked world materials and the prop
    /// materials of map_props.fbx, with team variants for team surfaces. Every material uses
    /// Luneraria/Surface (modes see the shader) or Luneraria/Pad. Idempotent: existing assets are
    /// updated in place, so scene references stay valid.
    /// </summary>
    public static class LuneMaterialFactory
    {
        public const string Folder = "Assets/Luneraria/Materials";
        public const string SetPath = Folder + "/LuneMaterials.asset";
        const string StoneMapPath = "Assets/Luneraria/Art/Textures/limestone-albedo.png";

        // Surface modes of Luneraria/Surface.
        public const int Plain = 0, Terrain = 1, Stone = 2, Paving = 3, Soil = 4, Bark = 5, Foliage = 6, Water = 7, Vein = 8, Crystal = 9;

        /// <summary>Team style (Blau, Rot, neutral grotto) of lune_materials.gd TEAM_STYLE.</summary>
        public static readonly Color[] TeamCrystal = { Hex("78c6ff"), Hex("ff7d45"), Hex("b784ff") };
        public static readonly Color[] TeamRune = { Hex("86d2ff"), Hex("ffae5a"), Hex("c29cff") };
        public static readonly Color[] TeamMetal = { new Color(.80f, .85f, .92f), new Color(.92f, .64f, .34f), new Color(.70f, .62f, .50f) };
        public static readonly Color[] TeamCloth = { Hex("2a5aa8"), Hex("9a2c20"), Hex("45305f") };
        public static readonly Color[] TeamLight = { Hex("8cc8ff"), Hex("ffae72"), Hex("b37cff") };
        public static readonly Color[] TeamColor = { Hex("5aa8ff"), Hex("ff6a55"), Hex("b37cff") };
        static readonly string[] TeamNames = { "Blau", "Rot", "Neutral" };

        sealed class Spec
        {
            public int Mode;
            public Color Base = Color.white;
            public float Roughness = .88f;
            public float Metallic;
            public Color Emission = Color.black;
            public float Energy;
            public bool VertexColor;
            public bool DoubleSided;
            public float StoneScale = .23f;
            public float Relief = .016f;
        }

        static Shader _surface;
        static Texture2D _stone;

        public static Color Hex(string hex)
        {
            ColorUtility.TryParseHtmlString("#" + hex, out Color color);
            return color;
        }

        /// <summary>
        /// An HDR emission value for an [HDR] material colour: Godot's emission (sRGB colour, linear
        /// energy multiplier) as the linear value Unity hands to the shader unchanged.
        /// </summary>
        public static Color Hdr(Color srgb, float energy)
        {
            Color linear = srgb.linear * energy;
            return new Color(linear.r, linear.g, linear.b, 1f);
        }

        /// <summary>
        /// A plain (non-HDR) colour that Unity converts from gamma to linear, carrying a linear
        /// value above one (RenderSettings.ambientLight = colour * energy).
        /// </summary>
        public static Color GammaEncoded(Color srgb, float energy)
        {
            Color linear = srgb.linear * energy;
            return new Color(Mathf.LinearToGammaSpace(linear.r), Mathf.LinearToGammaSpace(linear.g), Mathf.LinearToGammaSpace(linear.b), 1f);
        }

        public static LuneMaterialSet Build(LuneWorldBake bake, out Dictionary<int, Material> worldMaterials)
        {
            Directory.CreateDirectory(Folder + "/Buildings");
            Directory.CreateDirectory(Folder + "/World");
            Directory.CreateDirectory(Folder + "/Props");
            AssetDatabase.Refresh();
            _surface = Shader.Find("Luneraria/Surface");
            if (_surface == null)
                throw new InvalidOperationException("shader Luneraria/Surface missing");
            _stone = AssetDatabase.LoadAssetAtPath<Texture2D>(StoneMapPath);
            var set = AssetDatabase.LoadAssetAtPath<LuneMaterialSet>(SetPath);
            if (set == null)
            {
                set = ScriptableObject.CreateInstance<LuneMaterialSet>();
                AssetDatabase.CreateAsset(set, SetPath);
            }
            set.Entries.Clear();
            BuildingMaterials(set);
            PropMaterials(set);
            worldMaterials = WorldMaterials(bake);
            EditorUtility.SetDirty(set);
            AssetDatabase.SaveAssets();
            return set;
        }

        // ------------------------------------------------------------ G2 buildings and boss (LN_*)
        static void BuildingMaterials(LuneMaterialSet set)
        {
            Fixed(set, "LN_Stone_Pale", new Spec { Mode = Stone, Base = new Color(.72f, .68f, .61f), VertexColor = true });
            Fixed(set, "LN_Stone_Dark", new Spec { Mode = Stone, Base = new Color(.30f, .30f, .33f), Roughness = .9f, VertexColor = true });
            Fixed(set, "LN_Stone_Grotto", new Spec { Mode = Stone, Base = new Color(.43f, .43f, .46f), VertexColor = true });
            Fixed(set, "LN_Rock", new Spec { Mode = Stone, Base = new Color(.38f, .38f, .40f), Roughness = .93f, VertexColor = true, StoneScale = .13f });
            Teams(set, "LN_Metal_Team", team => new Spec { Mode = Plain, Base = TeamMetal[team] * .92f, Metallic = .9f, Roughness = .32f, VertexColor = true });
            Fixed(set, "LN_Metal_Iron", new Spec { Mode = Plain, Base = new Color(.24f, .24f, .26f), Metallic = .8f, Roughness = .52f, VertexColor = true });
            Fixed(set, "LN_Metal_Bronze", new Spec { Mode = Plain, Base = new Color(.66f, .47f, .24f), Metallic = .9f, Roughness = .42f, VertexColor = true });
            Teams(set, "LN_Crystal_Team", team => new Spec { Mode = Crystal, Base = TeamCrystal[team], Emission = TeamCrystal[team], Energy = 3.2f });
            Fixed(set, "LN_Crystal_Grotto", new Spec { Mode = Crystal, Base = TeamCrystal[2], Emission = TeamCrystal[2], Energy = 3.2f });
            // Godot lights only the glyph strokes of a rune band; a dim band stands in for them.
            Teams(set, "LN_Rune_Team", team => new Spec { Mode = Plain, Base = new Color(.16f, .16f, .18f), Emission = TeamRune[team], Energy = .45f, Roughness = .5f, VertexColor = true });
            Fixed(set, "LN_Rune_Grotto", new Spec { Mode = Plain, Base = new Color(.16f, .16f, .18f), Emission = TeamRune[2], Energy = .45f, Roughness = .5f, VertexColor = true });
            Teams(set, "LN_Cloth_Team", team => new Spec { Mode = Plain, Base = TeamCloth[team], Roughness = .85f, DoubleSided = true, VertexColor = true });
            Fixed(set, "LN_Water_Glow", new Spec { Mode = Plain, Base = new Color(.45f, .35f, .80f) * .3f, Emission = new Color(.45f, .35f, .80f), Energy = 1.2f, Roughness = .1f });
            Fixed(set, "LN_Boss_Hide", new Spec { Mode = Plain, Base = new Color(.24f, .25f, .29f), Roughness = .84f, VertexColor = true });
            Fixed(set, "LN_Boss_Bone", new Spec { Mode = Plain, Base = new Color(.74f, .71f, .64f), Roughness = .62f, VertexColor = true });
            Fixed(set, "LN_Boss_Bronze", new Spec { Mode = Plain, Base = new Color(.42f, .31f, .18f), Metallic = .85f, Roughness = .42f, VertexColor = true });
            // The grotto boss glows in the neutral colour; a deployed boss in its team's.
            Teams(set, "LN_Crystal_Boss", team => new Spec { Mode = Crystal, Base = TeamCrystal[team], Emission = TeamCrystal[team], Energy = 2.4f }, neutral: true);
            Fixed(set, "LN_Wood", new Spec { Mode = Plain, Base = new Color(.33f, .23f, .15f), Roughness = .82f, VertexColor = true });
            Fixed(set, "LN_Cave", new Spec { Mode = Plain, Base = new Color(.02f, .015f, .03f), Roughness = 1f });
        }

        // ------------------------------------------------------------ props of map_props.fbx (ENV_*)
        static void PropMaterials(LuneMaterialSet set)
        {
            const string props = "Assets/Luneraria/Art/Environment/map_props.fbx";
            foreach (Material source in AssetDatabase.LoadAllAssetsAtPath(props).OfType<Material>())
            {
                string key = source.name;
                Color color = source.HasProperty("_BaseColor") ? source.GetColor("_BaseColor") : source.color;
                Spec spec;
                if (key.Contains("brass"))
                    // Godot keeps the glTF material for brass (no Kluft surface).
                    spec = new Spec { Mode = Plain, Base = color, Metallic = source.HasProperty("_Metallic") ? source.GetFloat("_Metallic") : .8f, Roughness = .4f };
                else if (key.StartsWith("ENV_"))
                    spec = new Spec { Mode = SurfaceMode(key), Base = color };
                else
                    spec = new Spec { Mode = Plain, Base = color, Roughness = .8f, DoubleSided = true };
                Add(set, key, Create(Folder + "/Props/" + key + ".mat", spec), null, null);
            }
        }

        public static int SurfaceMode(string key)
        {
            if (key.Contains("leaf"))
                return Foliage;
            if (key.Contains("bark"))
                return Bark;
            if (key.Contains("soil"))
                return Soil;
            if (key.Contains("paving"))
                return Paving;
            return Stone;
        }

        // ------------------------------------------------------------ baked world materials
        static Dictionary<int, Material> WorldMaterials(LuneWorldBake bake)
        {
            var result = new Dictionary<int, Material>();
            var materials = (JArray)bake.Data["materials"];
            var veins = 0;
            for (int index = 0; index < materials.Count; index++)
            {
                var entry = (JObject)materials[index];
                string type = (string)entry["type"];
                string shader = (string)entry["shader"] ?? "";
                string key = (string)entry["surface_key"];
                JObject parameters = (JObject)entry["params"] ?? new JObject();
                string name;
                Spec spec;
                if (key != null)
                {
                    name = key;
                    spec = new Spec { Mode = SurfaceMode(key), Base = ColorOf(parameters["base_color"]) };
                }
                else if (shader.EndsWith("lune_terrain.gdshader"))
                {
                    name = "Terrain";
                    spec = new Spec { Mode = Terrain, StoneScale = .21f };
                }
                else if (shader.EndsWith("river.gdshader"))
                {
                    name = "River";
                    spec = new Spec { Mode = Water };
                }
                else if (shader.EndsWith("lune_vein.gdshader"))
                {
                    // Vein tint and seed are per-instance parameters in Godot; the builder assigns
                    // one material per vein (see VeinMaterial).
                    continue;
                }
                else if (shader.EndsWith("lune_pad.gdshader"))
                {
                    Color tint = ColorOf(parameters["tint"]);
                    int team = tint.r > tint.b ? 1 : 0;
                    name = "Pad_" + TeamNames[team];
                    result[index] = PadMaterial(Folder + "/World/" + name + ".mat", tint, (float)parameters["pad_length"], (float)parameters["row_start"]);
                    continue;
                }
                else if (type == "standard")
                {
                    Color albedo = ColorOf(entry["albedo"]);
                    bool glow = entry["emission"] != null;
                    name = "Glow_" + ColorUtility.ToHtmlStringRGB(albedo) + (glow ? "_" + ((float)entry["emission_energy"]).ToString("0.0#", System.Globalization.CultureInfo.InvariantCulture) : "");
                    spec = new Spec { Mode = Plain, Base = albedo, Roughness = (float)entry["roughness"], Metallic = (float)entry["metallic"] };
                    if (glow)
                    {
                        spec.Emission = ColorOf(entry["emission"]);
                        spec.Energy = (float)entry["emission_energy"];
                    }
                }
                else
                {
                    throw new InvalidOperationException("unknown world material " + entry);
                }
                result[index] = Create(Folder + "/World/" + name + ".mat", spec);
            }
            return result;
        }

        /// <summary>One material per energy vein (tint from its team, seed from the bake).</summary>
        public static Material VeinMaterial(string name, Color tint, float seed)
        {
            Material material = Create(Folder + "/World/" + name + ".mat", new Spec { Mode = Vein, Base = tint });
            material.SetFloat("_Seed", seed);
            material.SetFloat("_Energy", 1f);
            EditorUtility.SetDirty(material);
            return material;
        }

        static Material PadMaterial(string path, Color tint, float length, float rowStart)
        {
            Shader shader = Shader.Find("Luneraria/Pad");
            var material = AssetDatabase.LoadAssetAtPath<Material>(path);
            if (material == null)
            {
                material = new Material(shader);
                AssetDatabase.CreateAsset(material, path);
            }
            material.shader = shader;
            material.SetColor("_Tint", tint);
            material.SetFloat("_PadLength", length);
            material.SetFloat("_RowStart", rowStart);
            EditorUtility.SetDirty(material);
            return material;
        }

        public static Color ColorOf(JToken values)
        {
            return new Color((float)values[0], (float)values[1], (float)values[2], values.Count() > 3 ? (float)values[3] : 1f);
        }

        static void Fixed(LuneMaterialSet set, string key, Spec spec)
        {
            Add(set, key, Create(Folder + "/Buildings/" + key + ".mat", spec), null, null);
        }

        static void Teams(LuneMaterialSet set, string key, Func<int, Spec> spec, bool neutral = true)
        {
            Material blau = Create(Folder + "/Buildings/" + key + "_Blau.mat", spec(0));
            Material rot = Create(Folder + "/Buildings/" + key + "_Rot.mat", spec(1));
            Material none = neutral ? Create(Folder + "/Buildings/" + key + "_Neutral.mat", spec(2)) : blau;
            Add(set, key, none, blau, rot);
        }

        static void Add(LuneMaterialSet set, string key, Material neutral, Material blau, Material rot)
        {
            set.Entries.Add(new LuneMaterialSet.Entry { Key = key, Neutral = neutral, Blau = blau, Rot = rot });
        }

        static Material Create(string path, Spec spec)
        {
            var material = AssetDatabase.LoadAssetAtPath<Material>(path);
            if (material == null)
            {
                material = new Material(_surface);
                AssetDatabase.CreateAsset(material, path);
            }
            material.shader = _surface;
            material.enableInstancing = true;
            material.SetColor("_BaseColor", spec.Base);
            material.SetFloat("_Mode", spec.Mode);
            material.SetFloat("_VertexColor", spec.VertexColor ? 1f : 0f);
            material.SetFloat("_Metallic", spec.Metallic);
            material.SetFloat("_Roughness", spec.Roughness);
            material.SetColor("_EmissionColor", spec.Energy > 0f ? Hdr(spec.Emission, spec.Energy) : Color.black);
            material.SetFloat("_StoneScale", spec.StoneScale);
            material.SetFloat("_Relief", spec.Relief);
            material.SetFloat("_Cull", spec.DoubleSided ? 0f : 2f);
            material.SetTexture("_StoneMap", _stone);
            material.globalIlluminationFlags = MaterialGlobalIlluminationFlags.None;
            EditorUtility.SetDirty(material);
            return material;
        }
    }
}