// Copyright (c) AlphaSierraPapa for the SharpDevelop Team (for details please see \doc\copyright.txt)
// This code is distributed under the GNU LGPL (for details please see \doc\license.txt)
using System;
using System.Collections.Generic;
using Mono.Cecil.Cil;

namespace ICSharpCode.Decompiler.Disassembler
{
	public class ILCodeMapping
	{
		public int SourceCodeLine { get; set; }
		
		public Instruction ILInstruction { get; set; }
	}
	
	public class MethodMapping
	{
		public string TypeName { get; set; }
		
		public uint MetadataToken { get; set; }
		
		public List<ILCodeMapping> MethodCodeMappings { get; set; }
		
		/// <summary>
		/// Finds the IL instruction given a source code line number.
		/// </summary>
		/// <param name="sourceCodeLine">Source code line number.</param>
		/// <returns>IL Instruction or null, if the instruction was not found.</returns>
		public Instruction FindByLine(int sourceCodeLine)
		{
			if (sourceCodeLine <= 0)
				throw new ArgumentException("The source line must be greater thatn 0.");
			
			if (MethodCodeMappings == null || MethodCodeMappings.Count == 0)
				return null;
			
			foreach (var codeMapping in MethodCodeMappings) {
				if (codeMapping.SourceCodeLine == sourceCodeLine)
					return codeMapping.ILInstruction;
			}
			
			return null;
		}
		
		/// <summary>
		/// Finds the source code line given an IL instruction offset.
		/// </summary>
		/// <param name="instruction">IL Instruction offset.</param>
		/// <returns>Source code line, if it is found, -1 otherwise.</returns>
		public int FindByInstruction(int instructionOffset)
		{
			if (instructionOffset <= 0)
				throw new ArgumentNullException("The instruction offset cannot be lower than 0.");
			
			if (MethodCodeMappings == null || MethodCodeMappings.Count == 0)
				return -1;
			
			foreach (var codeMapping in MethodCodeMappings) {
				if (codeMapping.ILInstruction.Offset == instructionOffset)
					return codeMapping.SourceCodeLine;
			}
			
			return -1;
		}
	}
	
	public static class CodeMappings
	{
		static Dictionary<string, List<MethodMapping>> ilCodeMappings = new Dictionary<string, List<MethodMapping>>();
		
		/// <summary>
		/// Stores the source codes mappings: IL &lt;-&gt; editor lines
		/// </summary>
		public static Dictionary<string, List<MethodMapping>> ILSourceCodeMappings {
			get { return ilCodeMappings; }
			set { ilCodeMappings = value; }
		}
		
		public static ILCodeMapping GetInstructionByTypeAndLine(string typeName, int lineNumber, out uint metadataToken)
		{
			if (!ilCodeMappings.ContainsKey(typeName)) {
				metadataToken = 0;
				return null;
			}
			
			if (lineNumber <= 0) {
				metadataToken = 0;
				return null;
			}
			
			var methodMappings = ilCodeMappings[typeName];
			foreach (var maping in methodMappings) {
				var ilMap = maping.MethodCodeMappings.Find(m => m.SourceCodeLine == lineNumber);
				if (ilMap != null) {
					metadataToken = maping.MetadataToken;
					return ilMap;
				}
			}
			
			metadataToken = 0;
			return null;
		}
		
		public static void GetSourceCodeFromMetadataTokenAndOffset(uint token, int ilOffset, out string typeName, out int line)
		{
			typeName = null;
			line = 0;
			
			foreach (var typename in ilCodeMappings.Keys) {
				var mapping = ilCodeMappings[typename].Find(m => m.MetadataToken == token);
				if (mapping == null)
					continue;
				
				var ilCodeMapping = mapping.MethodCodeMappings.Find(cm => cm.ILInstruction.Offset == ilOffset);
				if (ilCodeMapping == null)
					continue;
				
				typeName = typename;
				line = ilCodeMapping.SourceCodeLine;
				break;
			}
		}
	}
}