using System.IO;
using UnityEditor;

namespace Chameleon.Editor.WebAssets
{
    /// <summary>Small shared helpers for the web-asset importer windows.</summary>
    public static class ImportUtil
    {
        public static string SanitizeFileName(string name)
        {
            foreach (var c in Path.GetInvalidFileNameChars())
                name = name.Replace(c, ' ');
            return name.Trim();
        }

        /// <summary>"2k"/"2K" -> 2. Unknown strings sort last.</summary>
        public static int ResolutionRank(string res)
        {
            if (string.IsNullOrEmpty(res)) return int.MaxValue;
            var digits = res.TrimEnd('k', 'K');
            return int.TryParse(digits, out var n) ? n : int.MaxValue;
        }

        /// <summary>Maps a "2k"-style resolution to a valid Unity max texture size.</summary>
        public static int ResolutionToMaxSize(string res)
        {
            int k = ResolutionRank(res);
            int px = k * 1024;
            int[] valid = { 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384 };
            foreach (var v in valid)
                if (px <= v) return v;
            return 16384;
        }

        public static void EnsureFolder(string folder)
        {
            if (AssetDatabase.IsValidFolder(folder))
                return;
            var parts = folder.Split('/');
            string cur = parts[0]; // "Assets"
            for (int i = 1; i < parts.Length; i++)
            {
                string next = $"{cur}/{parts[i]}";
                if (!AssetDatabase.IsValidFolder(next))
                    AssetDatabase.CreateFolder(cur, parts[i]);
                cur = next;
            }
        }

        /// <summary>
        /// Non-destructive folder-collision handling: if the folder exists, asks the user
        /// (New folder / Cancel / Overwrite). Returns the folder to use, or null on cancel.
        /// </summary>
        public static string ResolveFolderCollision(string folder, string dialogTitle)
        {
            if (!AssetDatabase.IsValidFolder(folder))
                return folder;

            int choice = EditorUtility.DisplayDialogComplex(dialogTitle,
                $"Folder already exists:\n{folder}", "New folder", "Cancel", "Overwrite");
            if (choice == 1) return null;                          // Cancel
            if (choice == 0) return AssetDatabase.GenerateUniqueAssetPath(folder); // New folder
            return folder;                                          // Overwrite
        }
    }
}