/*
 Copyright (c) 2013 yvt

 This file is part of OpenSpades.

 OpenSpades 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 3 of the License, or
 (at your option) any later version.

 OpenSpades 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 OpenSpades.  If not, see <http://www.gnu.org/licenses/>.

 */

#include <cstring>

#include <unzip/unzip.h>

// ioapi.h must be included after unzip.h
#include <unzip/ioapi.h>

#include <Core/Debug.h>
#include <Core/Exception.h>

#include "DynamicMemoryStream.h"
#include "IStream.h"
#include "ZipFileSystem.h"

namespace spades {
	class ZipFileSystem::ZipFileInputStream : public IStream {
		ZipFileSystem *fs;
		unzFile zip;
		uint64_t pos;

		bool streaming;

		// unzip library doesn't support opening multiple
		// file, but ZipFileSystem has to.
		// so when second file is open, the contents of
		// first file is read and is closed in unzip level.
		// read contents are stored in remainingData.
		// streaming becomes false.
		std::vector<unsigned char> remainingData;
		size_t remDataPos;

	public:
		ZipFileInputStream(ZipFileSystem *fs, unzFile zf) : fs(fs), zip(zf), streaming(true) {
			SPADES_MARK_FUNCTION();
		}

		~ZipFileInputStream() {
			SPADES_MARK_FUNCTION();
			if (streaming) {
				unzCloseCurrentFile(zip);
				SPAssert(this == fs->currentStream);
				fs->currentStream = NULL;
			}
		}

		void ForceCloseUnzipFile() {
			SPADES_MARK_FUNCTION();
			if (streaming) {
				streaming = false;
				unsigned char buf[1024];
				int bytes;
				while ((bytes = unzReadCurrentFile(zip, buf, sizeof(buf))) > 0) {
					remainingData.insert(remainingData.end(), buf, buf + bytes);
				}
				remDataPos = 0;

				int ret = unzCloseCurrentFile(zip);
				if (ret != UNZ_OK) {
					SPRaise("Zip file close error: 0x%08x", ret);
				}

				SPAssert(this == fs->currentStream);
				fs->currentStream = NULL;
			}
		}

		int ReadByte() override {
			SPADES_MARK_FUNCTION();
			int byte;
			if (streaming) {
				unsigned char b;
				int bytes = unzReadCurrentFile(zip, &b, 1);
				if (bytes < 0) {
					SPRaise("Unzip error: 0x%08x", bytes);
				} else if (bytes == 0) {
					byte = -1;
				} else {
					byte = b;
					pos++;
				}
			} else {
				if (remDataPos >= remainingData.size()) {
					return -1;
				} else {
					pos++;
					byte = remainingData[remDataPos];
					remDataPos++;
				}
			}
			return byte;
		}
		size_t Read(void *buf, size_t bytes) override {
			SPADES_MARK_FUNCTION();
			size_t outBytes;
			if (streaming) {
				int out = unzReadCurrentFile(zip, buf, (unsigned int)bytes);
				if (out < 0) {
					SPRaise("Unzip error: 0x%08x", bytes);
				}
				outBytes = (size_t)out;
			} else {
				outBytes = bytes;
				size_t rem = remainingData.size() - remDataPos;
				if (outBytes > rem)
					outBytes = rem;
				memcpy(buf, remainingData.data() + remDataPos, outBytes);

				remDataPos += outBytes;
			}

			pos += outBytes;
			return outBytes;
		}

		void WriteByte(int) override {
			SPADES_MARK_FUNCTION();
			SPUnsupported();
		}
		void Write(const void *, size_t bytes) override {
			SPADES_MARK_FUNCTION();
			SPUnsupported();
		}
		void Write(const std::string &) override {
			SPADES_MARK_FUNCTION();
			SPUnsupported();
		}

		uint64_t GetPosition() override { return pos; }
		void SetPosition(uint64_t) override {
			SPADES_MARK_FUNCTION();
			SPUnsupported();
		}

		uint64_t GetLength() override {
			SPADES_MARK_FUNCTION();
			ForceCloseUnzipFile();
			return pos + remainingData.size() - remDataPos;
		}
		void SetLength(uint64_t) override {
			SPADES_MARK_FUNCTION();
			SPUnsupported();
		}
	};

#pragma mark - Interface between ZipFileSystem and unzip

	class ZipFileSystem::ZipFileHandle {
		ZipFileSystem *fs;
		uint64_t pos;

		void ValidateCursor() {
			SPADES_MARK_FUNCTION();
			if (fs->cursorPos != pos) {
				fs->cursorPos = pos;
				fs->baseStream->SetPosition(pos);
			}
		}

	public:
		ZipFileHandle(ZipFileSystem *fs) : fs(fs) { pos = 0; }

		uint32_t Read(void *buf, uint32_t size) {
			SPADES_MARK_FUNCTION();
			ValidateCursor();
			size_t ret = fs->baseStream->Read(buf, size);
			pos += ret;
			fs->cursorPos += ret;
			return (uint32_t)ret;
		}

		uint32_t Write(void *buf, uint32_t size) {
			SPADES_MARK_FUNCTION();
			ValidateCursor();
			try {
				fs->baseStream->Write(buf, size);
			} catch (...) {
				// how many bytes written?
				size_t written = fs->baseStream->GetPosition() - pos;
				fs->cursorPos += written;
				pos += written;
				return pos;
			}
			pos += size;
			fs->cursorPos += size;
			return (uint32_t)size;
		}

		long Tell() { return (long)pos; }

		long Seek(int32_t offset, int origin) {
			switch (origin) {
				case ZLIB_FILEFUNC_SEEK_CUR: break;
				case ZLIB_FILEFUNC_SEEK_END: pos = fs->baseStream->GetLength(); break;
				case ZLIB_FILEFUNC_SEEK_SET: pos = 0; break;
			}
			pos += offset;
			return 0; // (long)pos;
		}

		int TestError() {
			return 0; // ??
		}
	};

	ZipFileSystem::ZipFileHandle *ZipFileSystem::InternalOpen(spades::ZipFileSystem *fs,
	                                                          const char *fn, int mode) {
		SPADES_MARK_FUNCTION();
		return new ZipFileHandle(fs);
	}

	uint32_t ZipFileSystem::InternalRead(spades::ZipFileSystem *fs,
	                                     spades::ZipFileSystem::ZipFileHandle *h, void *buf,
	                                     uint32_t size) {
		SPADES_MARK_FUNCTION_DEBUG();
		return h->Read(buf, size);
	}

	uint32_t ZipFileSystem::InternalWrite(spades::ZipFileSystem *fs,
	                                      spades::ZipFileSystem::ZipFileHandle *h, void *buf,
	                                      uint32_t size) {
		SPADES_MARK_FUNCTION_DEBUG();
		return h->Write(buf, size);
	}

	long ZipFileSystem::InternalTell(spades::ZipFileSystem *fs,
	                                 spades::ZipFileSystem::ZipFileHandle *h) {
		SPADES_MARK_FUNCTION_DEBUG();
		return h->Tell();
	}

	long ZipFileSystem::InternalSeek(spades::ZipFileSystem *fs,
	                                 spades::ZipFileSystem::ZipFileHandle *h, int32_t offset,
	                                 int origin) {
		SPADES_MARK_FUNCTION_DEBUG();
		return h->Seek(offset, origin);
	}

	int ZipFileSystem::InternalClose(spades::ZipFileSystem *fs,
	                                 spades::ZipFileSystem::ZipFileHandle *h) {
		SPADES_MARK_FUNCTION();
		delete h;
		return 0;
	}

	int ZipFileSystem::InternalTestError(spades::ZipFileSystem *fs,
	                                     spades::ZipFileSystem::ZipFileHandle *h) {
		SPADES_MARK_FUNCTION_DEBUG();
		return h->TestError();
	}

	zlib_filefunc_def ZipFileSystem::CreateZLibFileFunc() {
		zlib_filefunc_def def;
		def.opaque = this;
		def.zopen_file = (open_file_func)InternalOpen;
		def.zclose_file = (close_file_func)InternalClose;
		def.zread_file = (read_file_func)InternalRead;
		def.zwrite_file = (write_file_func)InternalWrite;
		def.ztell_file = (tell_file_func)InternalTell;
		def.zseek_file = (seek_file_func)InternalSeek;
		def.zerror_file = (testerror_file_func)InternalTestError;
		return def;
	}

#pragma mark - Zip file

	ZipFileSystem::ZipFileSystem(IStream *stream, bool autoClose)
	    : baseStream(stream), autoClose(autoClose) {
		SPADES_MARK_FUNCTION();

		cursorPos = stream->GetPosition();
		zlib_filefunc_def def = CreateZLibFileFunc();
		zip = unzOpen2("ZipFile.zip", &def);
		if (!zip) {
			SPRaise("Failed to open ZIP stream.");
		}

		currentStream = NULL;

		if (unzGoToFirstFile(zip) != UNZ_OK) {
			SPRaise("There was a problem while seeking the zip file to the first file.");
		}

		// create list of files
		do {
			char buf[513];
			buf[512] = 0;
			unzGetCurrentFileInfo(zip, nullptr, buf, 512, nullptr, 0, nullptr, 0);

			for (char *ptr = buf; *ptr; ptr++) {
				if (*ptr == '\\')
					*ptr = '/';
				else
					*ptr = tolower(*ptr);
			}

			unz_file_pos pos;
			if (unzGetFilePos(zip, &pos) != UNZ_OK) {
				SPRaise("unzGetFilePos failed");
			}
			files.insert(std::make_pair(buf, pos));
		} while (unzGoToNextFile(zip) == UNZ_OK);
	}

	ZipFileSystem::~ZipFileSystem() {
		SPADES_MARK_FUNCTION();
		if (currentStream) {
			currentStream->ForceCloseUnzipFile();
		}

		unzClose(zip);
	}

	std::unique_ptr<IStream> ZipFileSystem::OpenForReading(const char *fn) {
		SPADES_MARK_FUNCTION();

		if (currentStream) {
			currentStream->ForceCloseUnzipFile();
		}

		if (!MoveToFile(fn)) {
			SPFileNotFound(fn);
		}

		unzOpenCurrentFile(zip);
		try {
			currentStream = new ZipFileInputStream(this, zip);
			// load all data to allow seeking
			auto stream = stmp::make_unique<DynamicMemoryStream>();
			try {
				char buf[4096];
				size_t rd;
				while ((rd = currentStream->Read(buf, 4096)) > 0) {
					stream->Write(buf, rd);
				}
				currentStream->ForceCloseUnzipFile();
				stream->SetPosition(0);
				delete currentStream;
				return stream;
			} catch (...) {
				delete currentStream;
				throw;
			}
		} catch (...) {
			unzCloseCurrentFile(zip);
			throw;
		}
	}

	std::unique_ptr<IStream> ZipFileSystem::OpenForWriting(const char *fn) {
		SPADES_MARK_FUNCTION();
		SPRaise("ZIP file system doesn't support writing");
	}

	static bool MatchesZipFile(const char *fn, const char *path) {
		for (size_t i = 0;; i++) {
			if (path[i] == 0) {
				return true;
			}
			if (fn[i] == 0) {
				return false;
			}
			if ((fn[i] == '/' || fn[i] == '\\') && (path[i] == '/' || path[i] == '\\')) {
				continue;
			}
			if (tolower(fn[i]) != tolower(path[i]))
				return false;
		}
	}

	std::vector<std::string> ZipFileSystem::EnumFiles(const char *path) {

		if (currentStream) {
			currentStream->ForceCloseUnzipFile();
		}

		if (unzGoToFirstFile(zip) != UNZ_OK) {
			SPRaise("There was a problem while seeking the zip file to the first file.");
		}

		// FIXME: use `files` for faster search?
		std::vector<std::string> lst;
		size_t ln = strlen(path);
		do {
			char buf[513];
			buf[512] = 0;
			unzGetCurrentFileInfo(zip, nullptr, buf, 512, nullptr, 0, nullptr, 0);

			if (!MatchesZipFile(buf, path))
				continue;

			if (buf[ln] != '/' && buf[ln] != '\\') {
				// similar but bad pattern
				// path = foo
				// fn   = foobar\text.txt
				continue;
			}
			if (strchr(buf + ln + 1, '/') || strchr(buf + ln + 1, '\\')) {
				// similar but bad pattern
				// path = foo
				// fn   = foo\bar\text.txt
				continue;
			}
			lst.push_back(buf + ln + 1);
		} while (unzGoToNextFile(zip) == UNZ_OK);

		return lst;
	}

	bool ZipFileSystem::MoveToFile(const char *fn) {
		SPADES_MARK_FUNCTION();

		std::string f = fn;
		for (std::size_t i = 0; i < f.size(); i++) {
			if (f[i] == '\\')
				f[i] = '/';
			else
				f[i] = tolower(f[i]);
		}

		auto it = files.find(f);
		if (it == files.end()) {
			return false;
		}

		if (unzGoToFilePos(zip, &it->second) != UNZ_OK) {
			SPRaise("Failed to seek to the requested file.");
		}
		return true;
	}

	bool ZipFileSystem::FileExists(const char *fn) {
		SPADES_MARK_FUNCTION();

		std::string f = fn;
		for (std::size_t i = 0; i < f.size(); i++) {
			if (f[i] == '\\')
				f[i] = '/';
			else
				f[i] = tolower(f[i]);
		}

		return files.find(f) != files.end();
	}
}