#include <cerrno>
#include <cctype>
#include <ctime>
#include <algorithm>
#include <chrono>
#include <deque>
#include <string>

#include <sys/xattr.h>
#include <sys/stat.h>
#include <sys/paths.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

#include <strings.h>

#include <cpu/defs.h>
#include <cpu/CpuModule.h>
#include <cpu/fmem.h>

#include "os.h"
#include "toolbox.h"
#include "stackframe.h"


using ToolBox::Log;

namespace {

	using namespace OS;

	// time stuff.
	const long EpochAdjust = 86400 * (365 * (1970 - 1904) + 17); // 17 leap years.
	std::chrono::time_point<std::chrono::steady_clock> BootTime;



	// should make this public since it's needed by mpw/*
	uint16_t errno_to_oserr(int xerrno)
	{
		switch (xerrno)
		{
			case 0: return 0;
			case EBADF: return rfNumErr;
			case EIO: return ioErr;
			case EACCES: return permErr;
			case ENOENT: return fnfErr;
			case ENOTDIR: return dirNFErr;
			case EISDIR: return notAFileErr;
			case ENOTSUP: return extFSErr;
			case EROFS: return wPrErr;

			case EEXIST: return dupFNErr;

			case EBUSY: return fBsyErr;

			case EDQUOT: return dskFulErr;
			case ENOSPC: return dskFulErr;


			default:
				return ioErr;
		}

	}


	std::string extension(const std::string &s)
	{
		std::string tmp;
		int pos;

		pos = s.find_last_of("./:");

		if (pos == s.npos) return tmp;		
		if (s[pos++] != '.') return tmp;
		if (pos >= s.length()) return tmp;

		tmp = s.substr(pos);

		std::transform(tmp.begin(), tmp.end(), tmp.begin(), 
			[](char c) { return tolower(c); }
		);

		return tmp;
	}

	std::string basename(const std::string &s)
	{
		int pos = s.find_last_of("/:");
		if (pos == s.npos) return s;

		return s.substr(pos + 1);
	}


	// FSSpec garbage
	class FSSpecManager
	{
	public:

		const std::string &pathForID(int32_t id);
		int32_t idForPath(const std::string &path, bool insert = true);

	private:

		struct Entry
		{
			#if 0
			Entry(std::string &&p) : path(p), hash(std::hash(path))
			{}
			Entry(const std::string &p) : path(p), hash(std::hash(path))
			{} 
			#endif

			Entry(const std::string &&p, size_t h) :
				path(p), hash(h)
			{}

			std::string path;
			size_t hash;
		};

		std::deque<Entry> _pathQueue;
	};


	int32_t FSSpecManager::idForPath(const std::string &path, bool insert)
	{
		char buffer[PATH_MAX + 1];

		char *cp = realpath(path.c_str(), buffer);
		if (!cp) return -1;

		std::string s(cp);
		std::hash<std::string> hasher;
		size_t hash = hasher(s);

		int i = 1;
		for (const auto &e : _pathQueue)
		{
			if (e.hash == hash && e.path == s) return i;
			++i;
		}

		if (!insert) return -1;

		_pathQueue.emplace_back(Entry(std::move(s), hash));
		return _pathQueue.size();
	}


	const std::string &FSSpecManager::pathForID(int32_t id)
	{
		static std::string NullString;
		if (id < 1) return NullString;
		if (id > _pathQueue.size()) return NullString;

		return _pathQueue[id - 1].path;
	}
}

namespace OS
{

	bool Init()
	{
		BootTime = std::chrono::steady_clock::now();
		memoryWriteLong(0, 0x16A); // 0 ticks since boot.

		return true;
	}


	// known text file extensions
	bool IsTextFile(const std::string &s)
	{
		std::string ext = extension(s);
		if (ext.empty()) return false;

		char c = ext[0];
		switch(c)
		{
			case 'a':
				if (ext == "aii") // assembler
					return true;
				if (ext == "asm")
					return true;
				break;

			case 'c':
				if (ext == "c")
					return true;
				break;

			case 'e':
				if (ext == "equ") // asm iigs include file.
					return true;
				break;
			
			case 'i':
				if (ext == "i") // asmiigs include file
					return true;
				break;

			case 'h':
				if (ext == "h") // c header 
					return true;
				break;

			case 'l':
				if (ext == "lst") // asm iigs listing
					return true;
				break;

			case 'm':
				if (ext == "macros")
					return true;
				break;

			case 'p':
				if (ext == "pii") // pascal
					return true;
				break;

			case 'r':
				if (ext == "rii") // rez
					return true;
				break;

			case 's':
				if (ext == "src") // asm equates
					return true;
				break;

		}

		// check for e16.xxxx or m16.xxxx
		ext = basename(s);
		if (ext.length() > 4)
		{
			switch (ext[0])
			{
				case 'm':
				case 'M':
				case 'e':
				case 'E':
					if (!strncmp("16.", ext.c_str() + 1, 3))
						return true;
					break;
			}
		}

		return false;
	}

	// known binary file extensions
	bool IsBinaryFile(const std::string &s)
	{
		std::string ext = extension(s);
		if (ext.empty()) return false;

		char c = ext[0];
		switch(c)
		{
			case 'o':
				if (ext == "obj")
					return true;
				break;
		}

		return false;
	}

	uint16_t Close(uint16_t trap)
	{
		uint32_t d0;
		uint32_t parm = cpuGetAReg(0);

		Log("%04x Close(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint16_t ioRefNum = memoryReadWord(parm + 24);

		int rv = ::close(ioRefNum);
		if (rv < 0)
		{
			d0 = errno_to_oserr(errno);
		}
		else
		{
			d0 = 0;
		}


		memoryWriteWord(d0, parm + 16);
		return d0;
	}


	uint16_t Create(uint16_t trap)
	{
		uint32_t d0;

		uint32_t parm = cpuGetAReg(0);

		Log("%04x Create(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint32_t namePtr = memoryReadLong(parm + 18);

		//uint16_t ioVRefNum = memoryReadWord(parm + 22);
		//uint8_t ioFVersNum = memoryReadByte(parm + 26);

		std::string sname = ToolBox::ReadPString(namePtr, true);

		if (!sname.length())
		{
			memoryWriteWord(bdNamErr, parm + 16);
			return bdNamErr;
		}
		Log("     Create(%s)\n", sname.c_str());

		int fd;
		fd = ::open(sname.c_str(), O_WRONLY | O_CREAT | O_EXCL, 0666);

		if (fd < 0)
		{
			d0 = errno_to_oserr(errno);
		}
		else
		{
			::close(fd);
			d0 = 0;		
		}

		memoryWriteWord(d0, parm + 16);
		return d0;
	}

	uint16_t Open(uint16_t trap)
	{
		uint32_t d0;

		uint32_t parm = cpuGetAReg(0);

		Log("%04x Open(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint32_t namePtr = memoryReadLong(parm + 18);

		//uint16_t ioVRefNum = memoryReadWord(parm + 22);
		//uint8_t ioFVersNum = memoryReadByte(parm + 26);

		uint8_t ioPermission = memoryReadByte(parm + 27); 
		//uint32_t ioMisc = memoryReadLong(parm + 28);

		std::string sname = ToolBox::ReadPString(namePtr, true);

		if (!sname.length())
		{
			memoryWriteWord(bdNamErr, parm + 16);
			return bdNamErr;
		}
		Log("     Open(%s)\n", sname.c_str());


		int access = 0;
		switch(ioPermission)
		{
			case fsWrPerm:
			case fsRdWrPerm:
			case fsRdWrShPerm: 		
			case fsCurPerm:
				access = O_RDWR;
				break;
			case fsRdPerm:
				access = O_RDONLY;
				break;
			default:
				d0 = paramErr;
				memoryWriteWord(d0, parm + 16);
				return d0;
				break;
		}

		//todo -- FD table w/ flag for text/binary

		int fd = ::open(sname.c_str(), access);
		if (fd < 0 && ioPermission == fsCurPerm && errno == EACCES)
		{
			fd = ::open(sname.c_str(), O_RDONLY);
		}

		if (fd < 0)
		{
			d0 = errno_to_oserr(errno);
		}
		else
		{
			d0 = 0;
			memoryWriteWord(fd, parm + 24);	
		}

		memoryWriteWord(d0, parm + 16);
		return d0;
	}

	uint16_t Read(uint16_t trap)
	{
		uint32_t d0;
		uint32_t parm = cpuGetAReg(0);

		Log("%04x Read(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);

		uint16_t ioRefNum = memoryReadWord(parm + 24);
		uint32_t ioBuffer = memoryReadLong(parm + 32);
		int32_t ioReqCount = memoryReadLong(parm + 36);
		uint16_t ioPosMode = memoryReadWord(parm + 44);
		int32_t ioPosOffset = memoryReadLong(parm + 46);

		if (ioReqCount < 0)
		{
			d0 = paramErr;
			memoryWriteWord(d0, parm + 16);
			return d0;
		}

		off_t currentPos = ::lseek(ioRefNum, 0, SEEK_CUR);
		if (currentPos < 0)
		{
			if (errno != ESPIPE)
			{
				d0 = errno_to_oserr(errno);
				memoryWriteWord(d0, parm + 16);
				return d0;
			}
			currentPos = 0;
		}
		off_t pos = 0;

		switch(ioPosMode)
		{
			case fsFromStart:
				pos = ioPosOffset;
				break;
			case fsFromMark:
				pos = currentPos + ioPosOffset;
				break;
			case fsFromLEOF:
				{
					struct stat st;
					int rv;
					rv = ::fstat(ioRefNum, &st);
					if (rv < 0)
					{

					}
					pos = st.st_size + ioPosOffset;
				}
				break;
			case fsAtMark:
				pos = currentPos;
				break;
			default:
				d0 = paramErr;
				memoryWriteWord(d0, parm + 16);
				return d0;
				break;
		}

		if (pos != currentPos)
		{

			int rv = ::lseek(ioRefNum, pos, SEEK_SET);
			if (rv < 0)
			{
				d0 = paramErr;
				memoryWriteWord(d0, parm + 16);
				return d0;
			}
		}

		ssize_t count = ::read(ioRefNum, memoryPointer(ioBuffer), ioReqCount);
		if (count >= 0)
		{
			pos += count;
			memoryWriteLong(count, parm + 40);
		} 

		if (count == 0)
		{
			d0 = eofErr;
		}
		if (count < 0)
		{
			d0 = errno_to_oserr(errno);
		}

		memoryWriteLong(pos, parm + 46); // new offset.
		memoryWriteWord(d0, parm + 16);
		return d0;		

	}



	uint16_t Delete(uint16_t trap)
	{
		uint32_t d0;

		uint32_t parm = cpuGetAReg(0);

		Log("%04x Delete(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint32_t namePtr = memoryReadLong(parm + 18);

		//uint16_t ioVRefNum = memoryReadWord(parm + 22);
		//uint8_t ioFVersNum = memoryReadByte(parm + 26);

		std::string sname = ToolBox::ReadPString(namePtr, true);

		if (!sname.length())
		{
			memoryWriteWord(bdNamErr, parm + 16);
			return bdNamErr;
		}
		Log("     Delete(%s)\n", sname.c_str());

		int ok = ::unlink(sname.c_str());
		if (ok < 0)
			d0 = errno_to_oserr(errno);
		else
			d0 = 0;

		memoryWriteWord(d0, parm + 16);
		return d0;
	}

	uint16_t GetEOF(uint16_t trap)
	{
		uint32_t d0;
		size_t size;

		uint32_t parm = cpuGetAReg(0);

		Log("%04x GetEOF(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint16_t ioRefNum = memoryReadWord(parm + 24);

		struct stat st;

		if (::fstat(ioRefNum, &st) < 0)
		{
			d0 = errno_to_oserr(errno);
			size = 0;
		}
		else
		{
			d0 = 0;
			size = st.st_size;
		}

		memoryWriteWord(d0, parm + 16);
		memoryWriteLong(size, parm + 28);

		return d0;
	}



	// return the name of the default volume.
	// this does not translate well.
	uint16_t GetVol(uint16_t trap)
	{
		uint32_t parm = cpuGetAReg(0);

		Log("%04x GetVol(%08x)\n", trap, parm);


		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint32_t namePtr = memoryReadLong(parm + 18);

		// ioResult
		memoryWriteWord(0, parm + 16);
		// ioVRefNum
		memoryWriteWord(0, parm + 22);

		std::string tmp = "MacOS";
		ToolBox::WritePString(namePtr, tmp);

		return 0;
	}

	uint16_t GetFileInfo(uint16_t trap)
	{

		uint16_t d0;

		uint32_t parm = cpuGetAReg(0);

		Log("%04x GetFileInfo(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint32_t ioNamePtr = memoryReadLong(parm + 18);
		//uint16_t ioVRefNum = memoryReadWord(parm + 22);
		//uint8_t ioFVersNum = memoryReadByte(parm + 26);
		int16_t ioFDirIndex = memoryReadWord(parm + 28);

		if (ioFDirIndex <= 0)
		{
			// based name
			std::string sname;

			if (!ioNamePtr)
			{
				memoryWriteWord(bdNamErr, parm + 16);
				return bdNamErr;
			}

			sname = ToolBox::ReadPString(ioNamePtr, true);

			Log("     GetFileInfo(%s)\n", sname.c_str());

			// todo -- how are absolute, relative, etc paths handled...


			struct stat st;

			if (::stat(sname.c_str(), &st) < 0)
			{
				d0 = errno_to_oserr(errno);

				memoryWriteWord(d0, parm + 16);
				return d0;
			}

			// finder info
			{
				uint8_t buffer[32];
				std::memset(buffer, 0, sizeof(buffer));
				int rv;
				int xerrno;

				rv = ::getxattr(sname.c_str(), XATTR_FINDERINFO_NAME, buffer, 32, 0, 0);
				xerrno = errno;

				// override for source files.
				if (IsTextFile(sname))
				{
					std::memcpy(buffer, "TEXTMPS ", 8);
				}

				// only 16 bytes copied.
				std::memcpy(memoryPointer(parm + 32), buffer, 16);

			}


			// file reference number
			memoryWriteWord(0, parm + 24);
			// file attributes
			memoryWriteByte(0, parm + 30);
			// version (unused)
			memoryWriteByte(0, parm + 31);

			// file id
			memoryWriteLong(0, parm + 48);


			// file size
			memoryWriteWord(0, parm + 52);
			memoryWriteLong(st.st_size, parm + 54);
			memoryWriteLong(st.st_size, parm + 58);

			// create date.
			memoryWriteLong(UnixToMac(st.st_birthtime), parm + 72);
			memoryWriteLong(UnixToMac(st.st_mtime), parm + 76);

			// res fork...
			// do this last since it adjusts the name and the stat.

			sname.append(_PATH_RSRCFORKSPEC);
			if (::stat(sname.c_str(), &st) >= 0)
			{
				memoryWriteWord(0, parm + 62);
				memoryWriteLong(st.st_size, parm + 64);
				memoryWriteLong(st.st_size, parm + 68);
			}
			else
			{
				memoryWriteWord(0, parm + 62);
				memoryWriteLong(0, parm + 64);
				memoryWriteLong(0, parm + 68);
			}

			// no error.
			memoryWriteWord(0, parm + 16);


		}
		else
		{
			fprintf(stderr, "GetFileInfo -- ioFDirIndex not yet supported\n");
			exit(1);
		}

		// if iocompletion handler && asyn call....

		return 0;
	}

	uint16_t SetFileInfo(uint16_t trap)
	{
		std::string sname;
		uint16_t d0;


		uint32_t parm = cpuGetAReg(0);

		Log("%04x SetFileInfo(%08x)\n", trap, parm);

		//uint32_t ioCompletion = memoryReadLong(parm + 12);
		uint32_t ioNamePtr = memoryReadLong(parm + 18);
		//uint16_t ioVRefNum = memoryReadWord(parm + 22);
		//uint8_t ioFVersNum = memoryReadByte(parm + 26);
		//int16_t ioFDirIndex = memoryReadWord(parm + 28);

		// + 32 = finder data - 16 bytes.

		//uint32_t ioFlCrDat = memoryReadLong(parm + 72);
		//uint32_t ioFlMdDat = memoryReadLong(parm + 76);

		// currently, only sets finder info.

		if (!ioNamePtr)
		{
			memoryWriteWord(bdNamErr, parm + 16);
			return bdNamErr;
		}

		sname = ToolBox::ReadPString(ioNamePtr, true);
		Log("     SetFileInfo(%s)\n", sname.c_str());

		// check if the file actually exists
		{
			struct stat st;
			int ok;

			ok = ::stat(sname.c_str(), &st);
			if (ok < 0)
			{
				d0 = errno_to_oserr(errno);
				memoryWriteWord(d0, parm + 16);
				return d0; 
			}


		}

		// finder info is actually 32 bytes, so read and update the first 16.
		{
			uint8_t buffer[32];
			int ok;

			std::memset(buffer, 0, sizeof(buffer));

			ok = ::getxattr(sname.c_str(), XATTR_FINDERINFO_NAME, buffer, 32, 0, 0);

			// only 16 bytes copied.
			std::memcpy(buffer, memoryPointer(parm + 32), 16);

			ok = ::setxattr(sname.c_str(), XATTR_FINDERINFO_NAME, buffer, 32, 0, 0);	

			if (ok < 0)
			{
				d0 = errno_to_oserr(errno);
				memoryWriteWord(d0, parm + 16);
				return d0; 				
			}
		} 

		d0 = 0;
		memoryWriteWord(d0, parm + 16);
		return d0;
	}


	#pragma mark - String Utilities

	uint16_t CmpString(uint16_t trap)
	{

		/* 
		 * on entry:
		 * A0 Pointer to first character of first string
		 * A1 Pointer to first character of second string
		 * D0 (high) length of first string 
		 * D0 (low) length of second string
		 *
		 * on exit:
		 * D0 0 if strings equal, 1 if strings not equal.
		 *
		 */

		bool caseSens = trap & (1 << 9);
		//bool diacSens = trap & (1 << 10); // ignore for now...

		uint32_t aStr = cpuGetAReg(0);
		uint32_t bStr = cpuGetAReg(1);

		uint32_t length = cpuGetDReg(0);

		uint32_t aLen = (length >> 16);
		uint32_t bLen = (length & 0xffff);

		std::string a = ToolBox::ReadString(aStr, aLen);
		std::string b = ToolBox::ReadString(bStr, bLen);

		Log("%04x CmpString(%s, %s)\n", trap, a.c_str(), b.c_str());

		if (aLen != bLen) return 1; // different length...
		if (aStr == bStr) return 0; // same ptr...

		bool eq;
		eq = std::equal(
			a.begin(), 
			a.end(), 
			b.begin(), 
			[caseSens](char a, char b){
				if (!caseSens)
				{
					a = toupper(a);
					b = toupper(b);
				}
				return a == b;
			}
		);

		return eq ? 0 : 1;
	}


	#pragma mark - Time Utilities

	time_t UnixToMac(time_t t)
	{
		return t + EpochAdjust;
	}
	time_t MacToUnix(time_t t)
	{
		return t - EpochAdjust;
	}

	uint16_t ReadDateTime(uint16_t trap)
	{

		/* 
		 * on entry:
		 * A0 Pointer to long word secs
		 *
		 * on exit:
		 * A0 pointer to long word secs
		 * D0 Result code
		 *
		 */

		time_t now;

		uint32_t secsPtr = cpuGetAReg(0);

		Log("%04x ReadDateTime(%08x)\n", trap, secsPtr);

		now = ::time(NULL);


		now = UnixToMac(now);
		if (secsPtr) memoryWriteLong(now, secsPtr);

		// also set global variable Time.
		memoryWriteLong(now, 0x020c);
		return 0;
	}

	uint16_t SecondsToDate(uint16_t trap)
	{
		/* 
		 * on entry:
		 * D0 Seconds since midnight, January 1, 1904
		 * A0 pointer to date-time record
		 *
		 * on exit:
		 * D0 Result code
		 *
		 */

		uint32_t s = cpuGetDReg(0);
		uint32_t dtPtr = cpuGetAReg(0);

		Log("%04x SecondsToDate(%08x, %08x)\n", trap, s, dtPtr);


		if (dtPtr)
		{
			struct tm *tm;
			time_t t;
			t = MacToUnix(s);

			tm = ::localtime(&t);

			memoryWriteWord(tm->tm_year + 1900, dtPtr + 0);
			memoryWriteWord(tm->tm_mon + 1, dtPtr + 2);
			memoryWriteWord(tm->tm_mday, dtPtr + 4);
			memoryWriteWord(tm->tm_hour, dtPtr + 6);
			memoryWriteWord(tm->tm_min, dtPtr + 8);
			memoryWriteWord(tm->tm_sec, dtPtr + 10);
			memoryWriteWord(tm->tm_wday + 1, dtPtr + 12);
		}

		return 0;
	}

	uint16_t TickCount(uint16_t trap)
	{
		typedef std::chrono::duration<int32_t, std::ratio<1, 60> > ticks;

		Log("%04x TickCount()\n", trap);

		auto now = std::chrono::steady_clock::now();

		uint32_t t = std::chrono::duration_cast< ticks >(now - BootTime).count();


		// global Ticks
		memoryWriteLong(t, 0x16A);
		ToolReturn<4>(-1, t);

		return 0;
	}

	uint16_t Pack6(uint16_t trap)
	{
		char buffer[256];
		int length;
		std::string out;

		uint32_t dateTime;
		uint16_t flag;
		uint32_t result;
		uint16_t selector;

		// todo -- variable number of args.  Pop selector, act from that.

		StackFrame<12>(dateTime, flag, result, selector);

		Log("%04x Pack6(%08x, %04x, %08x, %04x)\n", 
			trap, dateTime, flag, result, selector);

		struct tm *tm;
		time_t t;
		t = MacToUnix(dateTime);

		tm = ::localtime(&t);

		if (selector == 0x00)
		{
			// void IUDateString(long dateTime,DateForm longFlag,Str255 result)
			// DateForm doesn't seem to do anything.

			// not strictly correct -- uses %d/%d/%2d form.
			length = std::strftime(buffer, sizeof(buffer), "%m/%d/%y", tm);
			out.assign(buffer, length);
		}
		else if (selector == 0x02)
		{
			// void IUTimeString(long dateTime,Boolean wantSeconds,Str255 result)
			// output: 12:00:00 AM or 12:00 AM

			length = std::strftime(buffer, sizeof(buffer), flag ? "%I:%M:%S %p" : "%I:%M %p", tm);

			out.assign(buffer, length);
		}
		else
		{
			fprintf(stderr, "Pack6: selector %04x not supported\n", selector);
			exit(1);
		}

		ToolBox::WritePString(result, out);
		return 0;
	}


}