/**************************************************************************/
/*  file_access_pack.cpp                                                  */
/**************************************************************************/
/*                         This file is part of:                          */
/*                             GODOT ENGINE                               */
/*                        https://godotengine.org                         */
/**************************************************************************/
/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur.                  */
/*                                                                        */
/* Permission is hereby granted, free of charge, to any person obtaining  */
/* a copy of this software and associated documentation files (the        */
/* "Software"), to deal in the Software without restriction, including    */
/* without limitation the rights to use, copy, modify, merge, publish,    */
/* distribute, sublicense, and/or sell copies of the Software, and to     */
/* permit persons to whom the Software is furnished to do so, subject to  */
/* the following conditions:                                              */
/*                                                                        */
/* The above copyright notice and this permission notice shall be         */
/* included in all copies or substantial portions of the Software.        */
/*                                                                        */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,        */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF     */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY   */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,   */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE      */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                 */
/**************************************************************************/

#include "file_access_pack.h"

#include "core/io/file_access_encrypted.h"
#include "core/object/script_language.h"
#include "core/os/os.h"
#include "core/version.h"

#include <stdio.h>

Error PackedData::add_pack(const String &p_path, bool p_replace_files, uint64_t p_offset) {
	for (int i = 0; i < sources.size(); i++) {
		if (sources[i]->try_open_pack(p_path, p_replace_files, p_offset)) {
			return OK;
		}
	}

	return ERR_FILE_UNRECOGNIZED;
}

void PackedData::add_path(const String &p_pkg_path, const String &p_path, uint64_t p_ofs, uint64_t p_size, const uint8_t *p_md5, PackSource *p_src, bool p_replace_files, bool p_encrypted) {
	String simplified_path = p_path.simplify_path();
	PathMD5 pmd5(simplified_path.md5_buffer());

	bool exists = files.has(pmd5);

	PackedFile pf;
	pf.encrypted = p_encrypted;
	pf.pack = p_pkg_path;
	pf.offset = p_ofs;
	pf.size = p_size;
	for (int i = 0; i < 16; i++) {
		pf.md5[i] = p_md5[i];
	}
	pf.src = p_src;

	if (!exists || p_replace_files) {
		files[pmd5] = pf;
	}

	if (!exists) {
		//search for dir
		String p = simplified_path.replace_first("res://", "");
		PackedDir *cd = root;

		if (p.contains("/")) { //in a subdir

			Vector<String> ds = p.get_base_dir().split("/");

			for (int j = 0; j < ds.size(); j++) {
				if (!cd->subdirs.has(ds[j])) {
					PackedDir *pd = memnew(PackedDir);
					pd->name = ds[j];
					pd->parent = cd;
					cd->subdirs[pd->name] = pd;
					cd = pd;
				} else {
					cd = cd->subdirs[ds[j]];
				}
			}
		}
		String filename = simplified_path.get_file();
		// Don't add as a file if the path points to a directory
		if (!filename.is_empty()) {
			cd->files.insert(filename);
		}
	}
}

void PackedData::add_pack_source(PackSource *p_source) {
	if (p_source != nullptr) {
		sources.push_back(p_source);
	}
}

PackedData *PackedData::singleton = nullptr;

PackedData::PackedData() {
	singleton = this;
	root = memnew(PackedDir);

	add_pack_source(memnew(PackedSourcePCK));
}

void PackedData::_free_packed_dirs(PackedDir *p_dir) {
	for (const KeyValue<String, PackedDir *> &E : p_dir->subdirs) {
		_free_packed_dirs(E.value);
	}
	memdelete(p_dir);
}

PackedData::~PackedData() {
	if (singleton == this) {
		singleton = nullptr;
	}

	for (int i = 0; i < sources.size(); i++) {
		memdelete(sources[i]);
	}
	_free_packed_dirs(root);
}

//////////////////////////////////////////////////////////////////

bool PackedSourcePCK::try_open_pack(const String &p_path, bool p_replace_files, uint64_t p_offset) {
	Ref<FileAccess> f = FileAccess::open(p_path, FileAccess::READ);
	if (f.is_null()) {
		return false;
	}

	bool pck_header_found = false;

	// Search for the header at the start offset - standalone PCK file.
	f->seek(p_offset);
	uint32_t magic = f->get_32();
	if (magic == PACK_HEADER_MAGIC) {
		pck_header_found = true;
	}

	// Search for the header in the executable "pck" section - self contained executable.
	if (!pck_header_found) {
		// Loading with offset feature not supported for self contained exe files.
		if (p_offset != 0) {
			ERR_FAIL_V_MSG(false, "Loading self-contained executable with offset not supported.");
		}

		int64_t pck_off = OS::get_singleton()->get_embedded_pck_offset();
		if (pck_off != 0) {
			// Search for the header, in case PCK start and section have different alignment.
			for (int i = 0; i < 8; i++) {
				f->seek(pck_off);
				magic = f->get_32();
				if (magic == PACK_HEADER_MAGIC) {
#ifdef DEBUG_ENABLED
					print_verbose("PCK header found in executable pck section, loading from offset 0x" + String::num_int64(pck_off - 4, 16));
#endif
					pck_header_found = true;
					break;
				}
				pck_off++;
			}
		}
	}

	// Search for the header at the end of file - self contained executable.
	if (!pck_header_found) {
		// Loading with offset feature not supported for self contained exe files.
		if (p_offset != 0) {
			ERR_FAIL_V_MSG(false, "Loading self-contained executable with offset not supported.");
		}

		f->seek_end();
		f->seek(f->get_position() - 4);
		magic = f->get_32();

		if (magic == PACK_HEADER_MAGIC) {
			f->seek(f->get_position() - 12);
			uint64_t ds = f->get_64();
			f->seek(f->get_position() - ds - 8);
			magic = f->get_32();
			if (magic == PACK_HEADER_MAGIC) {
#ifdef DEBUG_ENABLED
				print_verbose("PCK header found at the end of executable, loading from offset 0x" + String::num_int64(f->get_position() - 4, 16));
#endif
				pck_header_found = true;
			}
		}
	}

	if (!pck_header_found) {
		return false;
	}

	int64_t pck_start_pos = f->get_position() - 4;

	uint32_t version = f->get_32();
	uint32_t ver_major = f->get_32();
	uint32_t ver_minor = f->get_32();
	f->get_32(); // patch number, not used for validation.

	ERR_FAIL_COND_V_MSG(version != PACK_FORMAT_VERSION, false, "Pack version unsupported: " + itos(version) + ".");
	ERR_FAIL_COND_V_MSG(ver_major > VERSION_MAJOR || (ver_major == VERSION_MAJOR && ver_minor > VERSION_MINOR), false, "Pack created with a newer version of the engine: " + itos(ver_major) + "." + itos(ver_minor) + ".");

	uint32_t pack_flags = f->get_32();
	uint64_t file_base = f->get_64();

	bool enc_directory = (pack_flags & PACK_DIR_ENCRYPTED);
	bool rel_filebase = (pack_flags & PACK_REL_FILEBASE);

	for (int i = 0; i < 16; i++) {
		//reserved
		f->get_32();
	}

	int file_count = f->get_32();

	if (rel_filebase) {
		file_base += pck_start_pos;
	}

	if (enc_directory) {
		Ref<FileAccessEncrypted> fae;
		fae.instantiate();
		ERR_FAIL_COND_V_MSG(fae.is_null(), false, "Can't open encrypted pack directory.");

		Vector<uint8_t> key;
		key.resize(32);
		for (int i = 0; i < key.size(); i++) {
			key.write[i] = script_encryption_key[i];
		}

		Error err = fae->open_and_parse(f, key, FileAccessEncrypted::MODE_READ, false);
		ERR_FAIL_COND_V_MSG(err, false, "Can't open encrypted pack directory.");
		f = fae;
	}

	for (int i = 0; i < file_count; i++) {
		uint32_t sl = f->get_32();
		CharString cs;
		cs.resize(sl + 1);
		f->get_buffer((uint8_t *)cs.ptr(), sl);
		cs[sl] = 0;

		String path;
		path.parse_utf8(cs.ptr());

		uint64_t ofs = file_base + f->get_64();
		uint64_t size = f->get_64();
		uint8_t md5[16];
		f->get_buffer(md5, 16);
		uint32_t flags = f->get_32();

		PackedData::get_singleton()->add_path(p_path, path, ofs + p_offset, size, md5, this, p_replace_files, (flags & PACK_FILE_ENCRYPTED));
	}

	return true;
}

Ref<FileAccess> PackedSourcePCK::get_file(const String &p_path, PackedData::PackedFile *p_file) {
	return memnew(FileAccessPack(p_path, *p_file));
}

//////////////////////////////////////////////////////////////////

Error FileAccessPack::open_internal(const String &p_path, int p_mode_flags) {
	ERR_PRINT("Can't open pack-referenced file.");
	return ERR_UNAVAILABLE;
}

bool FileAccessPack::is_open() const {
	if (f.is_valid()) {
		return f->is_open();
	} else {
		return false;
	}
}

void FileAccessPack::seek(uint64_t p_position) {
	ERR_FAIL_COND_MSG(f.is_null(), "File must be opened before use.");

	if (p_position > pf.size) {
		eof = true;
	} else {
		eof = false;
	}

	f->seek(off + p_position);
	pos = p_position;
}

void FileAccessPack::seek_end(int64_t p_position) {
	seek(pf.size + p_position);
}

uint64_t FileAccessPack::get_position() const {
	return pos;
}

uint64_t FileAccessPack::get_length() const {
	return pf.size;
}

bool FileAccessPack::eof_reached() const {
	return eof;
}

uint64_t FileAccessPack::get_buffer(uint8_t *p_dst, uint64_t p_length) const {
	ERR_FAIL_COND_V_MSG(f.is_null(), -1, "File must be opened before use.");
	ERR_FAIL_COND_V(!p_dst && p_length > 0, -1);

	if (eof) {
		return 0;
	}

	int64_t to_read = p_length;
	if (to_read + pos > pf.size) {
		eof = true;
		to_read = (int64_t)pf.size - (int64_t)pos;
	}

	pos += to_read;

	if (to_read <= 0) {
		return 0;
	}
	f->get_buffer(p_dst, to_read);

	return to_read;
}

void FileAccessPack::set_big_endian(bool p_big_endian) {
	ERR_FAIL_COND_MSG(f.is_null(), "File must be opened before use.");

	FileAccess::set_big_endian(p_big_endian);
	f->set_big_endian(p_big_endian);
}

Error FileAccessPack::get_error() const {
	if (eof) {
		return ERR_FILE_EOF;
	}
	return OK;
}

void FileAccessPack::flush() {
	ERR_FAIL();
}

void FileAccessPack::store_buffer(const uint8_t *p_src, uint64_t p_length) {
	ERR_FAIL();
}

bool FileAccessPack::file_exists(const String &p_name) {
	return false;
}

void FileAccessPack::close() {
	f = Ref<FileAccess>();
}

FileAccessPack::FileAccessPack(const String &p_path, const PackedData::PackedFile &p_file) :
		pf(p_file),
		f(FileAccess::open(pf.pack, FileAccess::READ)) {
	ERR_FAIL_COND_MSG(f.is_null(), "Can't open pack-referenced file '" + String(pf.pack) + "'.");

	f->seek(pf.offset);
	off = pf.offset;

	if (pf.encrypted) {
		Ref<FileAccessEncrypted> fae;
		fae.instantiate();
		ERR_FAIL_COND_MSG(fae.is_null(), "Can't open encrypted pack-referenced file '" + String(pf.pack) + "'.");

		Vector<uint8_t> key;
		key.resize(32);
		for (int i = 0; i < key.size(); i++) {
			key.write[i] = script_encryption_key[i];
		}

		Error err = fae->open_and_parse(f, key, FileAccessEncrypted::MODE_READ, false);
		ERR_FAIL_COND_MSG(err, "Can't open encrypted pack-referenced file '" + String(pf.pack) + "'.");
		f = fae;
		off = 0;
	}
	pos = 0;
	eof = false;
}

//////////////////////////////////////////////////////////////////////////////////
// DIR ACCESS
//////////////////////////////////////////////////////////////////////////////////

Error DirAccessPack::list_dir_begin() {
	list_dirs.clear();
	list_files.clear();

	for (const KeyValue<String, PackedData::PackedDir *> &E : current->subdirs) {
		list_dirs.push_back(E.key);
	}

	for (const String &E : current->files) {
		list_files.push_back(E);
	}

	return OK;
}

String DirAccessPack::get_next() {
	if (list_dirs.size()) {
		cdir = true;
		String d = list_dirs.front()->get();
		list_dirs.pop_front();
		return d;
	} else if (list_files.size()) {
		cdir = false;
		String f = list_files.front()->get();
		list_files.pop_front();
		return f;
	} else {
		return String();
	}
}

bool DirAccessPack::current_is_dir() const {
	return cdir;
}

bool DirAccessPack::current_is_hidden() const {
	return false;
}

void DirAccessPack::list_dir_end() {
	list_dirs.clear();
	list_files.clear();
}

int DirAccessPack::get_drive_count() {
	return 0;
}

String DirAccessPack::get_drive(int p_drive) {
	return "";
}

PackedData::PackedDir *DirAccessPack::_find_dir(const String &p_dir) {
	String nd = p_dir.replace("\\", "/");

	// Special handling since simplify_path() will forbid it
	if (p_dir == "..") {
		return current->parent;
	}

	bool absolute = false;
	if (nd.begins_with("res://")) {
		nd = nd.replace_first("res://", "");
		absolute = true;
	}

	nd = nd.simplify_path();

	if (nd.is_empty()) {
		nd = ".";
	}

	if (nd.begins_with("/")) {
		nd = nd.replace_first("/", "");
		absolute = true;
	}

	Vector<String> paths = nd.split("/");

	PackedData::PackedDir *pd;

	if (absolute) {
		pd = PackedData::get_singleton()->root;
	} else {
		pd = current;
	}

	for (int i = 0; i < paths.size(); i++) {
		const String &p = paths[i];
		if (p == ".") {
			continue;
		} else if (p == "..") {
			if (pd->parent) {
				pd = pd->parent;
			}
		} else if (pd->subdirs.has(p)) {
			pd = pd->subdirs[p];

		} else {
			return nullptr;
		}
	}

	return pd;
}

Error DirAccessPack::change_dir(String p_dir) {
	PackedData::PackedDir *pd = _find_dir(p_dir);
	if (pd) {
		current = pd;
		return OK;
	} else {
		return ERR_INVALID_PARAMETER;
	}
}

String DirAccessPack::get_current_dir(bool p_include_drive) const {
	PackedData::PackedDir *pd = current;
	String p = current->name;

	while (pd->parent) {
		pd = pd->parent;
		p = pd->name.path_join(p);
	}

	return "res://" + p;
}

bool DirAccessPack::file_exists(String p_file) {
	p_file = fix_path(p_file);

	PackedData::PackedDir *pd = _find_dir(p_file.get_base_dir());
	if (!pd) {
		return false;
	}
	return pd->files.has(p_file.get_file());
}

bool DirAccessPack::dir_exists(String p_dir) {
	p_dir = fix_path(p_dir);

	return _find_dir(p_dir) != nullptr;
}

Error DirAccessPack::make_dir(String p_dir) {
	return ERR_UNAVAILABLE;
}

Error DirAccessPack::rename(String p_from, String p_to) {
	return ERR_UNAVAILABLE;
}

Error DirAccessPack::remove(String p_name) {
	return ERR_UNAVAILABLE;
}

uint64_t DirAccessPack::get_space_left() {
	return 0;
}

String DirAccessPack::get_filesystem_type() const {
	return "PCK";
}

DirAccessPack::DirAccessPack() {
	current = PackedData::get_singleton()->root;
}