using System.IO;
using SkiaSharp;
 
namespace Microsoft.Maui.Resizetizer
{
	internal class Resizer
	{
		public const string RasterFileExtension = ".png";
 
		SkiaSharpTools tools;
 
		public Resizer(ResizeImageInfo info, string intermediateOutputPath, ILogger logger)
		{
			Info = info;
			Logger = logger;
			IntermediateOutputPath = intermediateOutputPath;
		}
 
		public ILogger Logger { get; private set; }
 
		public string IntermediateOutputPath { get; private set; }
 
		public ResizeImageInfo Info { get; private set; }
 
		public SKSize? BaseSize => Info.BaseSize;
 
		protected SkiaSharpTools Tools =>
			tools ??= SkiaSharpTools.Create(Info.IsVector, Info.Filename, Info.BaseSize, Info.Color, Info.TintColor, Logger);
 
		public string GetRasterFileDestination(DpiPath dpi, bool includeIntermediate = true, bool includeScale = true)
			=> GetRasterFileDestination(Info, dpi, includeIntermediate ? IntermediateOutputPath : null, includeScale);
 
		public string GetFileDestination(DpiPath dpi, bool includeIntermediate = true, bool includeScale = true)
			=> GetFileDestination(Info, dpi, includeIntermediate ? IntermediateOutputPath : null, includeScale);
 
		public static string GetRasterFileDestination(ResizeImageInfo info, DpiPath dpi, string intermediateOutputPath = default, bool includeScale = true)
		{
			var destination = GetFileDestination(info, dpi, intermediateOutputPath, includeScale);
 
			if (info.OutputIsVector)
				destination = Path.ChangeExtension(destination, RasterFileExtension);
 
			return destination;
		}
 
		public static string GetFileDestination(ResizeImageInfo info, DpiPath dpi, string intermediateOutputPath = default, bool includeScale = true)
		{
			var destination = Path.Combine(dpi.Path, info.OutputName + (includeScale ? dpi.FileSuffix : dpi.NameSuffix) + info.OutputExtension);
 
			if (!string.IsNullOrEmpty(intermediateOutputPath))
			{
				var fullIntermediateOutputPath = new DirectoryInfo(intermediateOutputPath);
				destination = Path.Combine(fullIntermediateOutputPath.FullName, destination);
			}
 
			var fileInfo = new FileInfo(destination);
			if (!fileInfo.Directory.Exists)
				fileInfo.Directory.Create();
 
			return destination;
		}
 
		public ResizedImageInfo CopyFile(DpiPath dpi, string inputsFile)
		{
			var destination = GetRasterFileDestination(dpi);
 
			if (IsUpToDate(Info.Filename, destination, inputsFile, Logger))
				return new ResizedImageInfo { Filename = destination, Dpi = dpi };
 
			if (Info.IsVector)
				Rasterize(dpi, destination);
			else
				File.Copy(Info.Filename, destination, true);
 
			return new ResizedImageInfo { Filename = destination, Dpi = dpi };
		}
 
		static bool IsUpToDate(string inputFile, string outputFile, string inputsFile, ILogger logger)
		{
			var fileIn = new FileInfo(inputFile);
			var fileOut = new FileInfo(outputFile);
			var fileInputs = inputsFile is null ? null : new FileInfo(inputsFile);
 
			if (fileIn.Exists && fileOut.Exists && fileInputs?.Exists == true
				&& fileIn.LastWriteTimeUtc <= fileOut.LastWriteTimeUtc
				&& fileInputs.LastWriteTimeUtc <= fileOut.LastWriteTimeUtc)
			{
				logger.Log($"Skipping '{inputFile}' as output '{outputFile}' is already up to date.");
				return true;
			}
 
			return false;
		}
 
		public ResizedImageInfo Resize(DpiPath dpi, string inputsFile)
		{
			var destination = GetFileDestination(dpi);
 
			if (Info.IsVector)
				destination = Path.ChangeExtension(destination, RasterFileExtension);
 
			if (IsUpToDate(Info.Filename, destination, inputsFile, Logger))
				return new ResizedImageInfo { Filename = destination, Dpi = dpi };
 
			Rasterize(dpi, destination);
 
			return new ResizedImageInfo { Filename = destination, Dpi = dpi };
		}
 
		public SKSize GetOriginalSize() =>
			Tools.GetOriginalSize();
 
		void Rasterize(DpiPath dpi, string destination) =>
			Tools.Resize(dpi, destination);
	}
}