using System;
using System.IO;
using SabreTools.Numerics.Extensions;

namespace SabreTools.Wrappers
{
    public partial class WAD3 : IExtractable
    {
        /// <inheritdoc/>
        public bool Extract(string outputDirectory, bool includeDebug)
        {
            // If we have no lumps
            if (DirEntries.Length == 0)
                return false;

            // Loop through and extract all lumps to the output
            bool allExtracted = true;
            for (int i = 0; i < DirEntries.Length; i++)
            {
                allExtracted &= ExtractLump(i, outputDirectory, includeDebug);
            }

            return allExtracted;
        }

        /// <summary>
        /// Extract a lump from the WAD3 to an output directory by index
        /// </summary>
        /// <param name="index">Lump index to extract</param>
        /// <param name="outputDirectory">Output directory to write to</param>
        /// <param name="includeDebug">True to include debug data, false otherwise</param>
        /// <returns>True if the lump extracted, false otherwise</returns>
        public bool ExtractLump(int index, string outputDirectory, bool includeDebug)
        {
            // If we have no lumps
            if (DirEntries.Length == 0)
                return false;

            // If the lumps index is invalid
            if (index < 0 || index >= DirEntries.Length)
                return false;

            // Read the data -- TODO: Handle uncompressed lumps (see BSP.ExtractTexture)
            var lump = DirEntries[index];
            var data = ReadRangeFromSource((int)lump.Offset, (int)lump.Length);
            if (data.Length == 0)
                return false;

            // If we have an invalid output directory
            if (string.IsNullOrEmpty(outputDirectory))
                return false;

            // Ensure directory separators are consistent
            string filename = $"{lump.Name}.lmp";
            filename = filename.TrimStart(['\\', '/']);
            if (Path.DirectorySeparatorChar == '\\')
                filename = filename.Replace('/', '\\');
            else if (Path.DirectorySeparatorChar == '/')
                filename = filename.Replace('\\', '/');

            // Ensure the full output directory exists
            filename = Path.Combine(outputDirectory, filename);
            var directoryName = Path.GetDirectoryName(filename);
            if (directoryName is not null && !Directory.Exists(directoryName))
                Directory.CreateDirectory(directoryName);

            // Try to write the data
            try
            {
                // Open the output file for writing
                using var fs = File.Open(filename, FileMode.Create, FileAccess.Write, FileShare.None);
                fs.Write(data);
                fs.Flush();
            }
            catch (Exception ex)
            {
                if (includeDebug) Console.Error.WriteLine(ex);
                return false;
            }

            return true;
        }
    }
}