/**
 * @file		RDat.cpp
 * @date		20/09/2022
 * @author		JackCarterSmith
 * @copyright	GPL-v3.0
 * @brief		Rogue Dat file class interface.
 *
 */

#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <vector>
#include <boost/filesystem.hpp>
#include <RDI_Datatypes.h>
#include "DatEntry.h"
#include "data_struct.h"
#include "RDat.h"


using std::string;
using std::ios;
using std::vector;
using boost::filesystem::path;
using boost::filesystem::file_size;


namespace RDI {

RDat::RDat( string fPath ) {
	RDI_RESULT errCode = RDI_OK;

	this->workingDir = fPath;

	// Process header file and dump data file in memory.
	errCode = DumpLegacyFiles();
	if (errCode == RDI_ERROR_FILESYSTEM) {
		std::cout << "Data files (DATA.DAT/DATA.HDR) not found! Interrupt." << std::endl;
		return;
	} else if (errCode == RDI_ERROR_MEMORY) {
		std::cout << "Memory allocation or file access failed! Interrupt." << std::endl;
		return;
	}

	// Process data file tree and filter file subtype into list.
	ProcessFilesTree();
}

RDat::~RDat() {
	for ( DirectoryEntry* de : *pFTRoot )
		delete de;
	delete pFTRoot;
	free(rDatPtr);
	delete pDatSection;
}

string RDat::getDataSectionName( unsigned char id ) { return pDatSection->at(id).name; }
unsigned int RDat::getDataSectionOffset( unsigned char id ) { return pDatSection->at(id).offset; }

/**
 * Helper function to search for legacy DATA.DAT/HDR and dump it in memory.
 *
 * @return Error status.
 */
RDI_RESULT RDat::DumpLegacyFiles() {
	unsigned int i;
	path fp(workingDir);
	MEMFILE pTmpFile;

	// If input as a directory, assume it's contain DATA.DAT/HDR.
	if (boost::filesystem::is_directory(fp)) fp.append("DATA.HDR");

	// If file specified in input is the "datas" file, process the header (HDR) before.
	if (fp.extension() == ".DAT") fp.replace_extension(".HDR");

	// Open and parse data header file.
	//if (boost::filesystem::exists(fp)) return RDI_ERROR_FILESYSTEM;
	pTmpFile = MallocFile(fp);
	if (!pTmpFile) return RDI_ERROR_MEMORY;

	cDatSection = file_size(fp) / sizeof(T_HDR_ENTRY);
	pDatSection = new vector<struct dataSection>(cDatSection);
	for ( i = 0; i < pDatSection->size(); i++ ) {
		// Store header infos into structure to make easier access later.
		pDatSection->at(i).name.append(((T_HDR_ENTRY*)(pTmpFile + i * sizeof(T_HDR_ENTRY)))->section_name);
		pDatSection->at(i).offset = ((T_HDR_ENTRY*)(pTmpFile + i * sizeof(T_HDR_ENTRY)))->section_offset;
	}

	free(pTmpFile);

	// Dump data file and store it's pointer into class member.
	fp.replace_extension(".DAT");
	//if (boost::filesystem::exists(fp)) return RDI_ERROR_FILESYSTEM;
	rDatPtr = MallocFile(fp);
	if (!rDatPtr) return RDI_ERROR_MEMORY;

	return RDI_OK;
}

/**
 * Dump file into to newly allocated memory.
 * @param filePath File path.
 *
 * @return Start memory pointer of the file.
 */
MEMFILE RDat::MallocFile( path filePath ) {
	const unsigned int size = file_size(filePath);
	std::fstream rdf;
	MEMFILE fPtr = NULL;

	rdf.open(filePath.string(), ios::in | ios::binary);
	if (rdf.is_open()) {
		fPtr = (MEMFILE)malloc(size);
		rdf.read(fPtr, size);
		rdf.close();
	}

	return fPtr;
}

/**
 * Helper function to process files content for further use in this library.
 *
 * @return Error status.
 */
RDI_RESULT RDat::ProcessFilesTree() {
	unsigned int curEntriesCount = 0, i;
	DirectoryEntry* curDir = nullptr;
	MEMFILE pFileDescriptors = nullptr;

	// Create new root files tree. One per data section.
	pFTRoot = new std::vector<DirectoryEntry*>;
	pFTRoot->clear();
	for ( i = 0; i < cDatSection; i++ ) {
		curDir = new DirectoryEntry(pDatSection->at(i).name);
		pFTRoot->push_back(curDir);

		// Recalculate files descriptor offset for current section.
		pFileDescriptors = rDatPtr + pDatSection->at(i).offset +
				((T_DAT_SECTION*)(rDatPtr + pDatSection->at(i).offset))->file_headers_offset;
		curEntriesCount = (((T_DAT_SECTION*)(rDatPtr + pDatSection->at(i).offset))->file_headers_size) / 32;

		// Process arborescente in recursive method.
		ProcessDirectoryContents(curDir, pFileDescriptors, curEntriesCount, rDatPtr + pDatSection->at(i).offset);
	}

	return RDI_OK;
}

RDI_RESULT RDat::ProcessDirectoryContents( DirectoryEntry* pCurDir, MEMFILE pDesc, const unsigned int count, MEMFILE pSectionStart ) {
	unsigned int i, newDRECnt;
	DAT_FILE_FLAGS curEntryFlags = {0};

	FileEntry* newFile = nullptr;
	DirectoryEntry* newDir = nullptr;
	std::string tmpStr;

	if ( count == 0) return RDI_ERROR_PROCESS;

	for ( i = 0; i < count; i++ ) {
		curEntryFlags.raw = ((T_FILE_HEADER*)(pDesc + i * sizeof(T_FILE_HEADER)))->flags;

		tmpStr.clear();
		tmpStr.append(((T_FILE_HEADER*)(pDesc + i * sizeof(T_FILE_HEADER)))->name);

		// Test for file or directory
		if (!curEntryFlags.isDirectory) {
			newFile = new FileEntry(tmpStr, curEntryFlags,
					((T_FILE_HEADER*)(pDesc + i * sizeof(T_FILE_HEADER)))->datas_size,
					pSectionStart + ((T_FILE_HEADER*)(pDesc + i * sizeof(T_FILE_HEADER)))->datas_offset);
			pCurDir->AddEntry(newFile);
		} else {
			newDir = new DirectoryEntry(tmpStr, curEntryFlags);
			pCurDir->AddEntry(newDir);

			// Keep entries count in new directory to jump over after processing it.
			newDRECnt = (((T_FILE_HEADER*)(pDesc + i * sizeof(T_FILE_HEADER)))->dir_entries_size - sizeof(T_FILE_HEADER)) / sizeof(T_FILE_HEADER);
			ProcessDirectoryContents(newDir, pDesc + (i + 1) * sizeof(T_FILE_HEADER), newDRECnt, pSectionStart);
			if (newDRECnt <= count) i += newDRECnt;
		}
	}

	return RDI_OK;
}

DatEntry *RDat::getElement( boost::filesystem::path virtualDirPath ) {
	bool skip = false;
	boost::filesystem::path newPath;

	for ( DatEntry* de : *pFTRoot ) {
		if (virtualDirPath.size() == 1 || virtualDirPath.begin() == --virtualDirPath.end()) {
			if (de->getName() == virtualDirPath.filename().string())
				return de;
		} else {
			if (de->getName() == virtualDirPath.begin()->string()) {
				for (auto& sp : virtualDirPath) {
									if (skip)
										newPath.append(sp);
									skip = true;
								}
				return SearchSectionForEntry(dynamic_cast<DirectoryEntry *>(de), newPath);
			}
		}
	}

	return nullptr;
}

DatEntry *RDat::SearchSectionForEntry( DirectoryEntry *curDir, boost::filesystem::path virtualDirPath ) {
	bool skip = false;
	boost::filesystem::path newPath;

	for ( DatEntry* e : curDir->getFiles() ) {
		if (virtualDirPath.size() == 1 || virtualDirPath.begin() == --virtualDirPath.end()) {
			if (e->getName() == virtualDirPath.filename().string())
				return e;
		} else {
			if (e->isDirectory() && (e->getName() == virtualDirPath.begin()->string())) {
				for (auto& sp : virtualDirPath) {
					if (skip)
						newPath.append(sp);
					skip = true;
				}
				//TODO: add safety when trying to access inside a file
				return SearchSectionForEntry(dynamic_cast<DirectoryEntry *>(e), newPath);
			}
		}
	}

	return nullptr;
}

}