#include "pfc.h"

static_assert(L'Ö' == 0xD6, "Compile as Unicode!!!");

namespace pfc { namespace io { namespace path {

#ifdef _WINDOWS
#define KPathSeparators "\\/|"
#else
#define KPathSeparators "/"
#endif

string getFileName(string path) {
	t_size split = path.lastIndexOfAnyChar(KPathSeparators);
	if (split == ~0) return path;
	else return path.subString(split+1);
}
string getFileNameWithoutExtension(string path) {
	string fn = getFileName(path);
	t_size split = fn.lastIndexOf('.');
	if (split == ~0) return fn;
	else return fn.subString(0,split);
}
string getFileExtension(string path) {
	string fn = getFileName(path);
	t_size split = fn.lastIndexOf('.');
	if (split == ~0) return "";
	else return fn.subString(split);
}
string getDirectory(string filePath) {return getParent(filePath);}

string getParent(string filePath) {
	t_size split = filePath.lastIndexOfAnyChar(KPathSeparators);
	if (split == ~0) return "";
#ifdef _WINDOWS
	if (split > 0 && getIllegalNameChars().contains(filePath[split-1])) {
		if (split + 1 < filePath.length()) return filePath.subString(0,split+1);
		else return "";
	}
#endif
	return filePath.subString(0,split);
}
string combine(string basePath,string fileName) {
	if (basePath.length() > 0) {
		if (!isSeparator(basePath.lastChar())) {
			basePath += getDefaultSeparator();
		}
		return basePath + fileName;
	} else {
		//todo?
		return fileName;
	}
}

bool isSeparator(char c) {
    return strchr(KPathSeparators, c) != nullptr;
}
string getSeparators() {
	return KPathSeparators;
}

const char * charReplaceDefault(char c) {
	switch (c) {
	case '*':
		return "x";
	case '\"':
		return "\'\'";
	case ':':
	case '/':
	case '\\':
		return "-";
	case '?':
		return "";
	default:
		return "_";
	}
}

const char * charReplaceModern(char c) {
	switch (c) {
	case '*':
		return u8"∗";
	case '\"':
		return u8"''";
	case ':':
		return u8"∶";
	case '/':
		return u8"⁄";
	case '\\':
		return u8"⧵";
	case '?':
		return u8"？";
	case '<':
		return u8"˂";
	case '>':
		return u8"˃";
	case '|':
		return u8"∣";
	default:
		return "_";
	}
}

string replaceIllegalPathChars(string fn, charReplace_t replaceIllegalChar) {
	string illegal = getIllegalNameChars();
	string separators = getSeparators();
	string_formatter output;
	for(t_size walk = 0; walk < fn.length(); ++walk) {
		const char c = fn[walk];
		if (separators.contains(c)) {
			output.add_byte(getDefaultSeparator());
		} else if (string::isNonTextChar(c) || illegal.contains(c)) {
			string replacement = replaceIllegalChar(c);
			if (replacement.containsAnyChar(illegal)) /*per-OS weirdness security*/ replacement = "_";
			output << replacement.ptr();
		} else {
			output.add_byte(c);
		}
	}
	return output.toString();
}

string replaceIllegalNameChars(string fn, bool allowWC, charReplace_t replaceIllegalChar) {
	const string illegal = getIllegalNameChars(allowWC);
	string_formatter output;
	for(t_size walk = 0; walk < fn.length(); ++walk) {
		const char c = fn[walk];
		if (string::isNonTextChar(c) || illegal.contains(c)) {
			string replacement = replaceIllegalChar(c);
			if (replacement.containsAnyChar(illegal)) /*per-OS weirdness security*/ replacement = "_";
			output << replacement.ptr();
		} else {
			output.add_byte(c);
		}
	}
	return output.toString();
}

bool isInsideDirectory(pfc::string directory, pfc::string inside) {
	//not very efficient
	string walk = inside;
	for(;;) {
		walk = getParent(walk);
		if (walk == "") return false;
		if (equals(directory,walk)) return true;
	}
}
bool isDirectoryRoot(string path) {
	return getParent(path).isEmpty();
}
//OS-dependant part starts here


char getDefaultSeparator() {
#ifdef _WINDOWS
	return '\\';
#else
    return '/';
#endif
}

#ifdef _WINDOWS
#define KIllegalNameCharsEx ":<>\""
#else
// Mac OS allows : in filenames but does funny things presenting them in Finder, so don't use it
#define KIllegalNameCharsEx ":"
#endif

#define KWildcardChars "*?"
 
#define KIllegalNameChars KPathSeparators KIllegalNameCharsEx KWildcardChars
#define KIllegalNameChars_noWC KPathSeparators KIllegalNameCharsEx

static string g_illegalNameChars ( KIllegalNameChars );
static string g_illegalNameChars_noWC ( KIllegalNameChars_noWC );

string getIllegalNameChars(bool allowWC) {
	return allowWC ? g_illegalNameChars_noWC : g_illegalNameChars;
}

#ifdef _WINDOWS
static const char * const specialIllegalNames[] = {
	"con", "aux", "lst", "prn", "nul", "eof", "inp", "out"
};

enum { maxPathComponent = 255 };
static size_t safeTruncat( const char * str, size_t maxLen ) {
	size_t i = 0;
	size_t ret = 0;
	for( ; i < maxLen; ++ i ) {
		auto d = pfc::utf8_char_len( str + ret );
		if ( d == 0 ) break;
		ret += d;
	}
	return ret;
}

static size_t utf8_length( const char * str ) {
	size_t ret = 0;
	for (; ++ret;) {
		size_t d = pfc::utf8_char_len( str );
		if ( d == 0 ) break;
		str += d;
	}
	return ret;
}
static string truncatePathComponent( string name, bool preserveExt ) {
	
	if (name.length() <= maxPathComponent) return name;
	if (preserveExt) {
		auto dot = name.lastIndexOf('.');
		if (dot != pfc_infinite) {
			const auto ext = name.subString(dot);
			const auto extLen = utf8_length( ext.c_str() );
			if (extLen < maxPathComponent) {
				auto lim = maxPathComponent - extLen;
				lim = safeTruncat( name.c_str(), lim );
				if (lim < dot) {
					return name.subString(0, lim) + ext;
				}
			}
		}
	}

	size_t truncat = safeTruncat( name.c_str(), maxPathComponent );
	return name.subString(0, truncat);
}
#endif // _WINDOWS

static string trailingSanity(string name, bool preserveExt, const char * lstIllegal) {

	const auto isIllegalTrailingChar = [lstIllegal](char c) {
		return strchr(lstIllegal, c) != nullptr;
	};

	t_size end = name.length();
	if (preserveExt) {
		size_t offset = pfc::string_find_last(name.c_str(), '.');
		if (offset < end) end = offset;
	}
	const size_t endEx = end;
	while (end > 0) {
		if (!isIllegalTrailingChar(name[end - 1])) break;
		--end;
	}
	t_size begin = 0;
	while (begin < end) {
		if (!isIllegalTrailingChar(name[begin])) break;
		++begin;
	}
	if (end < endEx || begin > 0) {
		name = name.subString(begin, end - begin) + name.subString(endEx);
	}
	return name;
}
string validateFileName(string name, bool allowWC, bool preserveExt, charReplace_t replaceIllegalChar) {
	if (!allowWC) { // special fix for filenames that consist only of question marks
		size_t end = name.length();
		if (preserveExt) {
			size_t offset = pfc::string_find_last(name.c_str(), '.');
			if (offset < end) end = offset;
		}
		bool unnamed = true;
		for (size_t walk = 0; walk < end; ++walk) {
			if (name[walk] != '?') unnamed = false;
		}
		if (unnamed) {
			name = string("[unnamed]") + name.subString(end);
		}
	}
	
	// Trailing sanity AFTER replaceIllegalNameChars
	// replaceIllegalNameChars may remove chars exposing illegal prefix/suffix chars
	name = replaceIllegalNameChars(name, allowWC, replaceIllegalChar);
	if (name.length() > 0 && !allowWC) {
		pfc::string8 lstIllegal = " ";
		if (!preserveExt) lstIllegal += ".";

		name = trailingSanity(name, preserveExt, lstIllegal);
	}

#ifdef _WINDOWS
	name = truncatePathComponent(name, preserveExt);
	
	for( unsigned w = 0; w < _countof(specialIllegalNames); ++w ) {
		if (pfc::stringEqualsI_ascii( name.c_str(), specialIllegalNames[w] ) ) {
			name += "-";
			break;
		}
	}
#endif

	if (name.isEmpty()) name = "_";
	return name;
}

}}} // namespaces