using System;
using System.Collections.Generic;
using System.Text;

namespace Cosmos.Kernel.FileSystem {
	public partial class Ext2Old: FileSystem {

		private static unsafe GroupDescriptor[] ReadGroupDescriptorsOfBlock(byte aController, byte aDrive, uint aBlockGroup, SuperBlock aSuperBlock, ushort* aBuffer) {
			uint xGroupDescriptorCount = aSuperBlock.INodesCount / aSuperBlock.INodesPerGroup;
			GroupDescriptor[] xResult = new GroupDescriptor[xGroupDescriptorCount];
			GroupDescriptor* xDescriptorPtr = (GroupDescriptor*)aBuffer;
			for (int i = 0; i < xGroupDescriptorCount; i++) {
				int xATABlock = (int)((8));
				xATABlock += (i / 16);
				if ((i % 16) == 0) {
					if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, xATABlock, aBuffer)) {
						Console.WriteLine("[Ext2|GroupDescriptors] Error while reading GroupDescriptor data");
						return null;
					}
				}
				xResult[i] = xDescriptorPtr[i % 16];
			}
			return xResult;
		}

		public static unsafe void PrintAllFilesAndDirectories(byte aController, byte aDrive) {
            //ushort* xBuffer = (ushort*)Heap.MemAlloc(512);
            ushort* xBuffer = null;
            if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, 2, xBuffer)) {
				Console.WriteLine("[Ext2|SuperBlock] Error while reading SuperBlock data");
				return;
			}
			SuperBlock xSuperBlock = *(SuperBlock*)xBuffer;
			int xBlockSize = (int)(1024 << (byte)(xSuperBlock.LogBlockSize));
			uint xGroupsCount = xSuperBlock.INodesCount / xSuperBlock.INodesPerGroup;
			uint xGroupDescriptorsPerBlock = (uint)(xBlockSize / sizeof(GroupDescriptor));
			GroupDescriptor[] xGroupDescriptors = ReadGroupDescriptorsOfBlock(aController, aDrive, xSuperBlock.FirstDataBlock + 1, xSuperBlock, xBuffer);
			if (xGroupDescriptors == null) {
				return;
			}
			bool[] xUsedINodes = new bool[32];
			uint xCount = 0;
			INode* xINodeTable = (INode*)xBuffer;
			for (uint g = 0; g < xGroupDescriptors.Length; g++) {
				GroupDescriptor xGroupDescriptor = xGroupDescriptors[g];
				if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)((xGroupDescriptor.INodeBitmap) * 8), xBuffer)) {
					return;
				}
				if (!ConvertBitmapToBoolArray((uint*)xBuffer, xUsedINodes)) {
					return;
				}
				for (int i = 0; i < 32; i++) {
					if ((i % 4) == 0) {
						uint index = (uint)((i % xSuperBlock.INodesPerGroup) * sizeof(INode));
						uint offset = index / 512;
						if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)((xGroupDescriptor.INodeTable * 8) + offset), xBuffer)) {
							Console.WriteLine("[Ext2] Error reading INode table entries");
							return;
						}
					}
					uint xINodeIdentifier = (uint)((g * xSuperBlock.INodesPerGroup) + i + 1);
					if (xINodeIdentifier == 0xB) {
						continue;
					}
					if (xUsedINodes[i]) {
						INode xINode = xINodeTable[i % 4];
						//DebugUtil.SendExt2_INode((uint)((g * xSuperBlock.INodesPerGroup) + i), g, &xINodeTable[i % 4]);
						if ((xINode.Mode & INodeModeEnum.Directory) != 0) {
							//DebugUtil.SendNumber("Ext2", "Directory found", (uint)((g * xSuperBlock.INodesPerGroup) + i + 1), 32);
							if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)(xINode.Block1 * 8), xBuffer)) {
								Console.WriteLine("[Ext2] Error reading INode entries");
								return;
							}
							DirectoryEntry* xEntryPtr = (DirectoryEntry*)xBuffer;
							uint xTotalSize = xINode.Size;
							while (xTotalSize != 0/* && xEntryPtr->@INode != 0*/) {
								//DebugUtil.SendExt2_DirectoryEntry(xEntryPtr);
								uint xPtrAddress = (uint)xEntryPtr;
								//if (xEntryPtr->@INode == 0xC) {
								char[] xName = new char[xEntryPtr->NameLength];
								byte* xNamePtr = &xEntryPtr->FirstNameChar;
								for (int c = 0; c < xName.Length; c++) {
									xName[c] = (char)xNamePtr[c];
								}
								string s = new String(xName);
//								DebugUtil.SendMessage("Ext2, DirectoryEntryName", s);
								//}
								xPtrAddress += xEntryPtr->RecordLength;
								xTotalSize -= xEntryPtr->RecordLength;
								xEntryPtr = (DirectoryEntry*)xPtrAddress;
							}
						}
						xCount++;
					}
				}
			}

//			DebugUtil.SendNumber("Ext2", "Used INode count", xCount, 32);
		}

		public static unsafe byte[] ReadFile(byte aController, byte aDrive, string[] xPath) {
            //ushort* xBuffer = (ushort*)Heap.MemAlloc(512);
            ushort* xBuffer = null;
            if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, 2, xBuffer)) {
				Console.WriteLine("[Ext2|SuperBlock] Error while reading SuperBlock data");
				return null;
			}
			SuperBlock xSuperBlock = *(SuperBlock*)xBuffer;
			//DebugUtil.SendExt2_SuperBlock("ReadFileContents", &xSuperBlock);
			int xBlockSize = (int)(1024 << (byte)(xSuperBlock.LogBlockSize));
			uint xGroupsCount = xSuperBlock.INodesCount / xSuperBlock.INodesPerGroup;
			uint xGroupDescriptorsPerBlock = (uint)(xBlockSize / sizeof(GroupDescriptor));
			GroupDescriptor[] xGroupDescriptors = ReadGroupDescriptorsOfBlock(aController, aDrive, xSuperBlock.FirstDataBlock + 1, xSuperBlock, xBuffer);
			if (xGroupDescriptors == null) {
				return null;
			}
			bool[] xUsedINodes = new bool[32];
			uint xCount = 0;
			INode* xINodeTable = (INode*)xBuffer;
			uint xPathPointer = 0;
			uint xCurrentINode = 2;
			Console.WriteLine("Looking up directories");
			Console.Write("    xPath.Length = ");
			Hardware.Storage.ATAOld.WriteNumber((uint)xPath.Length, 16);
			Console.WriteLine("");
			int xIterations = 0;
			while (xPathPointer != (xPath.Length + 1)) {
				if (xIterations == 5) {
					Console.WriteLine("DEBUG: Stopping iteration");
					break;
				}
				Console.WriteLine("Searching items");
				Console.Write("    xPathPointer = ");
				Hardware.Storage.ATAOld.WriteNumber(xPathPointer, 16);
				Console.WriteLine("");
				Console.Write("    xCurrentINode = ");
				Hardware.Storage.ATAOld.WriteNumber(xCurrentINode, 32);
				Console.WriteLine("");

//				DebugUtil.SendNumber("Ext2", "Current INode", xCurrentINode, 32);
				for (uint g = 0; g < xGroupDescriptors.Length; g++) {
					GroupDescriptor xGroupDescriptor = xGroupDescriptors[g];
					if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)((xGroupDescriptor.INodeBitmap) * 8), xBuffer)) {
						return null;
					}
					if (!ConvertBitmapToBoolArray((uint*)xBuffer, xUsedINodes)) {
						return null;
					}
					for (int i = 0; i < 32; i++) {
						if ((i % 4) == 0) {
							uint index = (uint)((i % xSuperBlock.INodesPerGroup) * sizeof(INode));
							uint offset = index / 512;
							if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)((xGroupDescriptor.INodeTable * 8) + offset), xBuffer)) {
								Console.WriteLine("[Ext2] Error reading INode table entries");
								return null;
							}
						}
						uint xINodeIdentifier = (uint)((g * xSuperBlock.INodesPerGroup) + i + 1);
						//DebugUtil.SendNumber("Ext2", "Checking INode", xINodeIdentifier, 32);
						if (xINodeIdentifier != xCurrentINode) {
							continue;
						}
						if (xUsedINodes[i]) {
							INode xINode = xINodeTable[i % 4];
							//DebugUtil.SendExt2_INode((uint)((g * xSuperBlock.INodesPerGroup) + i), g, &xINodeTable[i % 4]);
							if (xPathPointer == xPath.Length) {
								#region temporary checks
								if (xINode.Block2 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block3 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block4 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block5 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block6 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block7 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block8 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block9 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block10 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block11 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block12 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block13 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block14 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								if (xINode.Block15 != 0) {
									Console.WriteLine("Multiblock files not supported yet!");
									return null;
								}
								#endregion
								Console.WriteLine("Get file contents now");
								if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)(xINode.Block1 * 8), xBuffer)) {
									Console.WriteLine("[Ext2] Error reading INode entries");
									return null;
								}
								byte[] xResult = new byte[512];
								byte* xByteBuff = (byte*)xBuffer;
								for (int b = 0; b < 512; b++) {
									xResult[b] = xByteBuff[b];
								}
								return xResult;
							} else {
								if ((xINode.Mode & INodeModeEnum.Directory) != 0) {
									//DebugUtil.SendNumber("Ext2", "Directory found", (uint)((g * xSuperBlock.INodesPerGroup) + i + 1), 32);
									//DebugUtil.SendExt2_INode(xINodeIdentifier, g, &xINodeTable[i % 4]);
									//DebugUtil.SendExt2_INodeMode(xINodeIdentifier, (ushort)xINode.Mode);
									if (!Hardware.Storage.ATAOld.ReadDataNew(aController, aDrive, (int)(xINode.Block1 * 8), xBuffer)) {
										Console.WriteLine("[Ext2] Error reading INode entries");
										return null;
									}
									DirectoryEntry* xEntryPtr = (DirectoryEntry*)xBuffer;
									uint xTotalSize = xINode.Size;
									while (xTotalSize != 0/* && xEntryPtr->@INode != 0*/) {
										//DebugUtil.SendExt2_DirectoryEntry(xEntryPtr);
										uint xPtrAddress = (uint)xEntryPtr;
										char[] xName = new char[xEntryPtr->NameLength];
										byte* xNamePtr = &xEntryPtr->FirstNameChar;
										for (int c = 0; c < xName.Length; c++) {
											xName[c] = (char)xNamePtr[c];
										}
										if (EqualsName(xPath[xPathPointer], xName)) {
											xPathPointer++;
											xCurrentINode = xEntryPtr->@INode;
											continue;
										}
										xPtrAddress += xEntryPtr->RecordLength;
										xTotalSize -= xEntryPtr->RecordLength;
										xEntryPtr = (DirectoryEntry*)xPtrAddress;
									}
								}
							}
							xCount++;
						}
					}
				}
			}
			//DebugUtil.SendMessage("Ext2", "Lookup file now");
			//DebugUtil.SendExt2_SuperBlock("Looking up file", &xSuperBlock);
			//Console.WriteLine("Lookup file now:");
			//DebugUtil.SendNumber("Ext2", "CurrentINode", xCurrentINode, 32);
			//uint xGroup = xCurrentINode / xSuperBlock.INodesPerGroup;
			//uint xGroupINodeBase = xGroup * xSuperBlock.INodesPerGroup;
			//for (int i = 0; i < 32; i++) {
			//    if ((i % 4) == 0) {
			//        uint index = (uint)((i % xSuperBlock.INodesPerGroup) * sizeof(INode));
			//        uint offset = index / 512;
			//        if (!Hardware.Storage.ATA.ReadDataNew(aController, aDrive, (int)((xGroupDescriptors[xGroup].INodeTable * 8) + offset), xBuffer)) {
			//            Console.WriteLine("[Ext2] Error reading INode entries");
			//            return null;
			//        }
			//    }
			//    INode xItem = xINodeTable[i % 4];
			//    if (((xGroupINodeBase + i) == xCurrentINode) && ((xItem.Mode & INodeModeEnum.RegularFile) != 0)) {
			//        DebugUtil.SendExt2_INode(xCurrentINode, xGroup, &xItem);
			//        Console.WriteLine("File found :-)");
			//        //return null;
			//    }
			//}
			//Console.WriteLine("Directory found");
			//DebugUtil.SendNumber("Ext2", "Used INode count", xCount, 32);
			Console.WriteLine("TODO: Lookup File now");
			return null;
		}

		private static unsafe bool ConvertBitmapToBoolArray(uint* aBitmap, bool[] aArray) {
			if (aArray == null || aArray.Length != 32) {
				Console.WriteLine("[ConvertBitmapToBoolArray] Incorrect Array");
				return false;
			}
			uint xValue = *aBitmap;
			for (byte b = 0; b < 32; b++) {
				uint xCheckBit = (uint)(1 << b);
				aArray[b] = (xValue & xCheckBit) != 0;
			}
			return true;
		}

		private static bool EqualsName(string a1, char[] a2) {
			if (a1 == null || a2 == null) {
				return false;
			}
			if (a1.Length != a2.Length) {
				return false;
			}
			for (int i = 0; i < a1.Length; i++) {
				if (a1[i] != a2[i]) {
					return false;
				}
			}
			return true;
		}
	}
}