/*
** filesystem.cpp
**
** This file is part of mkxp.
**
** Copyright (C) 2013 Jonas Kulla <Nyocurio@gmail.com>
**
** mkxp is free software: you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation, either version 2 of the License, or
** (at your option) any later version.
**
** mkxp is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with mkxp.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "filesystem.h"

#include "util.h"
#include "exception.h"

#include "physfs.h"

#include <QHash>
#include <QByteArray>

#include "stdio.h"
#include "string.h"

#include <QDebug>

struct RGSS_entryData
{
	int64_t offset;
	uint64_t size;
	uint32_t startMagic;
};

struct RGSS_entryHandle
{
	RGSS_entryData data;
	uint32_t currentMagic;
	uint64_t currentOffset;
	PHYSFS_Io *io;

	RGSS_entryHandle(const RGSS_entryData &data)
	    : data(data),
	      currentMagic(data.startMagic),
	      currentOffset(0)
	{}

	RGSS_entryHandle(const RGSS_entryHandle &other)
	    : data(other.data),
	      currentMagic(other.currentMagic),
	      currentOffset(other.currentOffset)
	{}
};

typedef QList<QByteArray> QByteList;

struct RGSS_archiveData
{
	PHYSFS_Io *archiveIo;
	QHash<QByteArray, RGSS_entryData> entryHash;
	QHash<QByteArray, bool> dirHash;
};

static bool
readUint32(PHYSFS_Io *io, uint32_t &result)
{
	char buff[4];
	PHYSFS_sint64 count = io->read(io, buff, 4);

	result = ((buff[0] << 0x00) & 0x000000FF) |
	         ((buff[1] << 0x08) & 0x0000FF00) |
	         ((buff[2] << 0x10) & 0x00FF0000) |
	         ((buff[3] << 0x18) & 0xFF000000) ;

	return (count == 4);
}

#define RGSS_HEADER_1 0x53534752
#define RGSS_HEADER_2 0x01004441

#define RGSS_MAGIC 0xDEADCAFE

#define PHYSFS_ALLOC(type) \
	static_cast<type*>(PHYSFS_getAllocator()->Malloc(sizeof(type)))

static inline uint32_t
advanceMagic(uint32_t &magic)
{
	uint32_t old = magic;

	magic = magic * 7 + 3;

	return old;
}

struct MagicState
{
	uint32_t magic;
	uint64_t offset;

	MagicState(uint64_t offset = 0)
	    : offset(offset)
	{
		magic = RGSS_MAGIC;

		for (uint i = 0; i < (offset/4); ++i)
			advanceBlock();
	}

	uint8_t advancePath()
	{
		uint8_t ret = magic & 0xFF;

		offset++;
		advanceBlock();

		return ret;
	}

	uint8_t advanceData()
	{
		uint8_t ret = magic & 0xFF;

		if (offset++ % 4 == 0)
			advanceBlock();

		return ret;
	}

private:
	void advanceBlock()
	{
		magic = magic * 7 + 3;
	}
};

static PHYSFS_sint64
RGSS_ioRead(PHYSFS_Io *self, void *buffer, PHYSFS_uint64 len)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	uint64_t toRead = min<uint64_t>(entry->data.size - entry->currentOffset, len);
	uint64_t offs = entry->currentOffset;

	entry->io->seek(entry->io, entry->data.offset + offs);

	uint64_t buffI = 0;
	for (uint64_t o = offs; o < offs + toRead;)
	{
		uint8_t bitOffset = (0x8 * (o % 4));
		uint8_t magicByte = (entry->currentMagic >> bitOffset) & 0xFF;

		uint8_t byte;
		entry->io->read(entry->io, &byte, 1);

		((uint8_t*) buffer)[buffI++] = byte ^ magicByte;

		if (++o % 4 == 0)
			advanceMagic(entry->currentMagic);
	}

	entry->currentOffset += toRead;

	return toRead;
}

static int
RGSS_ioSeek(PHYSFS_Io *self, PHYSFS_uint64 offset)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	if (offset == entry->currentOffset)
		return 1;

	if (offset > entry->data.size-1)
		return 0;

	/* If rewinding, we need to rewind to begining */
	if (offset < entry->currentOffset)
	{
		entry->currentOffset = 0;
		entry->currentMagic = entry->data.startMagic;
	}

	/* For each 4 bytes sought, advance magic */
	uint64_t dwordsSought = (offset - entry->currentOffset) / 4;
	for (uint64_t i = 0; i < dwordsSought; ++i)
		advanceMagic(entry->currentMagic);

	entry->currentOffset = offset;
	entry->io->seek(entry->io, entry->data.offset + entry->currentOffset);

	return 1;
}

static PHYSFS_sint64
RGSS_ioTell(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	return entry->currentOffset;
}

static PHYSFS_sint64
RGSS_ioLength(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	return entry->data.size;
}

static PHYSFS_Io*
RGSS_ioDuplicate(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);
	RGSS_entryHandle *entryDup = new RGSS_entryHandle(*entry);

	PHYSFS_Io *dup = PHYSFS_ALLOC(PHYSFS_Io);
	*dup = *self;
	dup->opaque = entryDup;

	return dup;
}

static void
RGSS_ioDestroy(PHYSFS_Io *self)
{
	RGSS_entryHandle *entry = static_cast<RGSS_entryHandle*>(self->opaque);

	delete entry;

	PHYSFS_getAllocator()->Free(self);
}

static const PHYSFS_Io RGSS_IoTemplate =
{
    0, /* version */
    0, /* opaque */
    RGSS_ioRead,
    0, /* write */
    RGSS_ioSeek,
    RGSS_ioTell,
    RGSS_ioLength,
    RGSS_ioDuplicate,
    0, /* flush */
    RGSS_ioDestroy
};

static void*
RGSS_openArchive(PHYSFS_Io *io, const char *, int forWrite)
{
	if (forWrite)
		return 0;

	/* Check header */
	uint32_t header1, header2;
	readUint32(io, header1);
	readUint32(io, header2);

	if (header1 != RGSS_HEADER_1 || header2 != RGSS_HEADER_2)
		return 0;

	RGSS_archiveData *data = new RGSS_archiveData;
	data->archiveIo = io;

	uint32_t magic = RGSS_MAGIC;

	while (true)
	{
		/* Read filename length,
         * if nothing was read, no files remain */
		uint32_t nameLen;
		if (!readUint32(io, nameLen))
			break;

		nameLen ^= advanceMagic(magic);

		static char nameBuf[512];
		uint i;
		for (i = 0; i < nameLen; ++i)
		{
			char c;
			io->read(io, &c, 1);
			nameBuf[i] = c ^ (advanceMagic(magic) & 0xFF);
			if (nameBuf[i] == '\\')
				nameBuf[i] = '/';
		}
		nameBuf[i] = 0;

		uint32_t entrySize;
		readUint32(io, entrySize);
		entrySize ^= advanceMagic(magic);

		RGSS_entryData entry;
		entry.offset = io->tell(io);
		entry.size = entrySize;
		entry.startMagic = magic;

		data->entryHash.insert(nameBuf, entry);

		/* Test for new folder */
		for (i = nameLen; i > 0; i--)
			if (nameBuf[i] == '/')
			{
				nameBuf[i] = '\0';
				if (!data->dirHash.contains(nameBuf))
					data->dirHash.insert(nameBuf, true);
			}

		io->seek(io, entry.offset + entry.size);
	}

	return data;
}

static void
RGSS_enumerateFiles(void *opaque, const char *dirname,
                    PHYSFS_EnumFilesCallback cb,
                    const char *origdir, void *callbackdata)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	QString dirn(dirname);

	char dirBuf[512];
	char baseBuf[512];
	QByteList keys = data->entryHash.keys();
	keys += data->dirHash.keys();

	Q_FOREACH (const QByteArray &filename, keys)
	{
		/* Get the filename directory part */
		strcpy(dirBuf, filename.constData());
		strcpy(baseBuf, filename.constData());

		/* Extract path and basename */
		const char *dirpath = "";
		char *basename = dirBuf;

		for (int i = filename.size(); i >= 0; i--)
			if (dirBuf[i] == '/')
			{
				dirBuf[i] = '\0';
				dirpath = dirBuf;

				basename = &dirBuf[i+1];

				break;
			}

		/* Compare to provided dirname */
		if (strcmp(dirpath, dirname) == 0)
			cb(callbackdata, origdir, basename);
	}
}

static PHYSFS_Io*
RGSS_openRead(void *opaque, const char *filename)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	if (!data->entryHash.contains(filename))
		return 0;

	RGSS_entryHandle *entry = new RGSS_entryHandle(data->entryHash[filename]);
	entry->io = data->archiveIo->duplicate(data->archiveIo);

	PHYSFS_Io *io = PHYSFS_ALLOC(PHYSFS_Io);

	*io = RGSS_IoTemplate;
	io->opaque = entry;

	return io;
}

static int
RGSS_stat(void *opaque, const char *filename, PHYSFS_Stat *stat)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	bool hasFile = data->entryHash.contains(filename);
	bool hasDir  = data->dirHash.contains(filename);

	if (!hasFile && !hasDir)
	{
		PHYSFS_setErrorCode(PHYSFS_ERR_NOT_FOUND);
		return 0;
	}

	stat->modtime    =
	stat->createtime =
	stat->accesstime = 0;
	stat->readonly   = 1;

	if (hasFile)
	{
		RGSS_entryData &entry = data->entryHash[filename];

		stat->filesize = entry.size;
		stat->filetype = PHYSFS_FILETYPE_REGULAR;
	}
	else
	{
		stat->filesize = 0;
		stat->filetype = PHYSFS_FILETYPE_DIRECTORY;
	}

	return 1;
}

static void
RGSS_closeArchive(void *opaque)
{
	RGSS_archiveData *data = static_cast<RGSS_archiveData*>(opaque);

	delete data;
}

static PHYSFS_Io*
RGSS_noop1(void*, const char*)
{
	return 0;
}

static int
RGSS_noop2(void*, const char*)
{
	return 0;
}

static const PHYSFS_Archiver RGSS_Archiver =
{
	0,
    {
        "RGSSAD",
        "RGSS encrypted archive format",
        "Jonas Kulla <Nyocurio@gmail.com>",
        "http://k-du.de/rgss/rgss.html",
        0 /* symlinks not supported */
    },
    RGSS_openArchive,
    RGSS_enumerateFiles,
    RGSS_openRead,
    RGSS_noop1, /* openWrite */
    RGSS_noop1, /* openAppend */
    RGSS_noop2, /* remove */
    RGSS_noop2, /* mkdir */
    RGSS_stat,
    RGSS_closeArchive
};

FileStream::FileStream(PHYSFS_File *file)
{
	p = file;
}

FileStream::~FileStream()
{
//	if (p)
//		PHYSFS_close(p);
}

void FileStream::operator=(const FileStream &o)
{
	p = o.p;
}

sf::Int64 FileStream::read(void *data, sf::Int64 size)
{
	if (!p)
		return -1;

	return PHYSFS_readBytes(p, data, size);
}

sf::Int64 FileStream::seek(sf::Int64 position)
{
	if (!p)
		return -1;

	int success = PHYSFS_seek(p, (PHYSFS_uint64) position);

	return success ? position : -1;
}

sf::Int64 FileStream::tell()
{
	if (!p)
		return -1;

	return PHYSFS_tell(p);
}

sf::Int64 FileStream::getSize()
{
	if (!p)
		return -1;

	return PHYSFS_fileLength(p);
}

sf::Int64 FileStream::write(const void *data, sf::Int64 size)
{
	if (!p)
		return -1;

	return PHYSFS_writeBytes(p, data, size);
}

void FileStream::close()
{
	if (p)
	{
		PHYSFS_close(p);
		p = 0;
	}
}

static void enumCB(void *, const char *origdir,
                   const char *fname)
{
	qDebug() << origdir << fname;
	char buf[128];
	sprintf(buf, "%s/%s", origdir, fname);
	PHYSFS_enumerateFilesCallback(buf, enumCB, 0);
}

FileSystem::FileSystem(const char *argv0)
{
	PHYSFS_init(argv0);
	PHYSFS_registerArchiver(&RGSS_Archiver);
}

FileSystem::~FileSystem()
{
	if (PHYSFS_deinit() == 0)
		qDebug() << "PhyFS failed to deinit.";
}

void FileSystem::addPath(const char *path)
{
	PHYSFS_mount(path, 0, 1);
}

static const char *imgExt[] =
{
	"jpg",
	"png"
};

static const char *audExt[] =
{
//	"mid",
//	"midi",
	"mp3",
	"ogg",
	"wav",
	"wma"  // FIXME this prolly isn't even supported lol
};

static const char *fonExt[] =
{
    "ttf"
};

struct FileExtensions
{
	const char **ext;
	int count;
} fileExtensions[] =
{
	{ imgExt, ARRAY_SIZE(imgExt) },
	{ audExt, ARRAY_SIZE(audExt) },
	{ fonExt, ARRAY_SIZE(fonExt) }
};

static const char *completeFileName(const char *filename,
                                    FileSystem::FileType type)
{
	static char buff[1024];

	if (PHYSFS_exists(filename))
		return filename;

	if (type != FileSystem::Undefined)
	{
		FileExtensions *extTest = &fileExtensions[type];
		for (int i = 0; i < extTest->count; ++i)
		{
			snprintf(buff, sizeof(buff), "%s.%s", filename, extTest->ext[i]);
			if (PHYSFS_exists(buff))
				return buff;
		}
	}

	return 0;
}

static PHYSFS_File *openReadInt(const char *filename,
                                FileSystem::FileType type)
{
	const char *foundName = completeFileName(filename, type);

	if (!foundName)
		throw Exception(Exception::NoFileError,
	                "No such file or directory - %s", filename);

	PHYSFS_File *handle = PHYSFS_openRead(foundName);
	if (!handle)
		throw Exception(Exception::PHYSFSError, "PhysFS: %s", PHYSFS_getLastError());

	PHYSFS_fileLength(handle);

	return handle;
}

FileStream FileSystem::openRead(const char *filename,
                                FileType type)
{
	PHYSFS_File *handle = openReadInt(filename, type);

	return FileStream(handle);
}

static inline PHYSFS_File *sdlPHYS(SDL_RWops *ops)
{
	return static_cast<PHYSFS_File*>(ops->hidden.unknown.data1);
}

static Sint64 SDL_RWopsSize(SDL_RWops *ops)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return -1;

	return PHYSFS_fileLength(f);
}

static Sint64 SDL_RWopsSeek(SDL_RWops *ops, Sint64 offset, int whence)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return -1;

	Sint64 base;
	switch (whence)
	{
	default:
	case RW_SEEK_SET :
		base = 0;
		break;
	case RW_SEEK_CUR :
		base = PHYSFS_tell(f);
		break;
	case RW_SEEK_END :
		base = PHYSFS_fileLength(f);
		break;
	}

	int result = PHYSFS_seek(f, base + offset);

	return (result != 0) ? PHYSFS_tell(f) : -1;
}

static size_t SDL_RWopsRead(SDL_RWops *ops, void *buffer, size_t size, size_t maxnum)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return 0;

	PHYSFS_sint64 result = PHYSFS_readBytes(f, buffer, size*maxnum);

	return (result != -1) ? (result / size) : 0;
}

static size_t SDL_RWopsWrite(SDL_RWops *ops, const void *buffer, size_t size, size_t num)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return 0;

	PHYSFS_sint64 result = PHYSFS_writeBytes(f, buffer, size*num);

	return (result != -1) ? (result / size) : 0;
}

static int SDL_RWopsClose(SDL_RWops *ops)
{
	PHYSFS_File *f = sdlPHYS(ops);

	if (!f)
		return -1;

	int result = PHYSFS_close(f);

	f = 0;

	return (result != 0) ? 0 : -1;
}

const Uint32 SDL_RWOPS_PHYSFS = SDL_RWOPS_UNKNOWN+10;

void FileSystem::openRead(SDL_RWops &ops,
                          const char *filename,
                          FileType type)
{
	PHYSFS_File *handle = openReadInt(filename, type);

	ops.size  = SDL_RWopsSize;
	ops.seek  = SDL_RWopsSeek;
	ops.read  = SDL_RWopsRead;
	ops.write = SDL_RWopsWrite;
	ops.close = SDL_RWopsClose;

	ops.type = SDL_RWOPS_PHYSFS;
	ops.hidden.unknown.data1 = handle;
}

bool FileSystem::exists(const char *filename, FileType type)
{
	const char *foundName = completeFileName(filename, type);

	return (foundName != 0);
}