/*
 * REminiscence - Flashback interpreter
 * Copyright (C) 2005-2019 Gregory Montoir (cyx@users.sourceforge.net)
 */

#ifdef _WIN32
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#else
#include <dirent.h>
#include <sys/stat.h>
#include <sys/param.h>
#endif
#ifdef USE_RWOPS
#include <SDL_rwops.h>
#endif
#include "fs.h"
#include "util.h"

struct FileName {
	char *name;
	int dir;
};

struct FileSystem_impl {

	char **_dirsList;
	int _dirsCount;
	FileName *_filesList;
	int _filesCount;

	FileSystem_impl() :
		_dirsList(0), _dirsCount(0), _filesList(0), _filesCount(0) {
	}

	~FileSystem_impl() {
		for (int i = 0; i < _dirsCount; ++i) {
			free(_dirsList[i]);
		}
		free(_dirsList);
		for (int i = 0; i < _filesCount; ++i) {
			free(_filesList[i].name);
		}
		free(_filesList);
	}

	void setRootDirectory(const char *dir) {
		getPathListFromDirectory(dir);
		debug(DBG_FILE, "Found %d files and %d directories", _filesCount, _dirsCount);
	}

	int findPathIndex(const char *name) const {
		for (int i = 0; i < _filesCount; ++i) {
			if (strcasecmp(_filesList[i].name, name) == 0) {
				return i;
			}
		}
		return -1;
	}

	char *getPath(const char *name) const {
		const int i = findPathIndex(name);
		if (i >= 0) {
			const char *dir = _dirsList[_filesList[i].dir];
			const int len = strlen(dir) + 1 + strlen(_filesList[i].name) + 1;
			char *p = (char *)malloc(len);
			if (p) {
				snprintf(p, len, "%s/%s", dir, _filesList[i].name);
			}
			return p;
		}
		return 0;
	}

	void addPath(const char *dir, const char *name) {
		int index = -1;
		for (int i = 0; i < _dirsCount; ++i) {
			if (strcmp(_dirsList[i], dir) == 0) {
				index = i;
				break;
			}
		}
		if (index == -1) {
			_dirsList = (char **)realloc(_dirsList, (_dirsCount + 1) * sizeof(char *));
			if (_dirsList) {
				_dirsList[_dirsCount] = strdup(dir);
				index = _dirsCount;
				++_dirsCount;
			}
		}
		_filesList = (FileName *)realloc(_filesList, (_filesCount + 1) * sizeof(FileName));
		if (_filesList) {
			_filesList[_filesCount].name = strdup(name);
			_filesList[_filesCount].dir = index;
			++_filesCount;
		}
	}

	void getPathListFromDirectory(const char *dir);
};

#ifdef _WIN32
void FileSystem_impl::getPathListFromDirectory(const char *dir) {
	WIN32_FIND_DATA findData;
	char searchPath[MAX_PATH];
	snprintf(searchPath, sizeof(searchPath), "%s/*", dir);
	HANDLE h = FindFirstFile(searchPath, &findData);
	if (h) {
		do {
			if (findData.cFileName[0] == '.') {
				continue;
			}
			char filePath[MAX_PATH];
			snprintf(filePath, sizeof(filePath), "%s/%s", dir, findData.cFileName);
			if (findData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) {
				getPathListFromDirectory(filePath);
			} else {
				addPath(dir, findData.cFileName);
			}
		} while (FindNextFile(h, &findData));
		FindClose(h);
	}
}
#else
void FileSystem_impl::getPathListFromDirectory(const char *dir) {
	DIR *d = opendir(dir);
	if (d) {
		dirent *de;
		while ((de = readdir(d)) != NULL) {
			if (de->d_name[0] == '.') {
				continue;
			}
			char filePath[MAXPATHLEN];
			snprintf(filePath, sizeof(filePath), "%s/%s", dir, de->d_name);
			struct stat st;
			if (stat(filePath, &st) == 0) {
				if (S_ISDIR(st.st_mode)) {
					getPathListFromDirectory(filePath);
				} else {
					addPath(dir, de->d_name);
				}
			}
		}
		closedir(d);
	}
}
#endif

FileSystem::FileSystem(const char *dataPath) {
	_impl = new FileSystem_impl;
	_impl->setRootDirectory(dataPath);
}

FileSystem::~FileSystem() {
	delete _impl;
}

char *FileSystem::findPath(const char *filename) const {
	return _impl->getPath(filename);
}

bool FileSystem::exists(const char *filename) const {
	if (_impl->findPathIndex(filename) >= 0) {
		return true;
	}
#ifdef USE_RWOPS
	SDL_RWops *rw = SDL_RWFromFile(filename, "rb");
	if (rw) {
		SDL_RWclose(rw);
		return true;
	}
#endif
	return false;
}