/*
 * This code is part of the programming language Ivy.
 * Ivy comes with ABSOLUTELY NO WARRANTY and is licensed under AGPL-3.0 or later.
 *    Copyright (C) 2024  VegOwOtenks
 *
 * This program 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.
 *
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

#include "StringView.h"

#include <ctype.h>
#include <string.h>
#include <stdint.h>

StringView StringView_FromString(const char* source)
{
	return StringView_FromStringSized(source, strlen(source));
}

StringView StringView_FromStringSized(const char* source, size_t length)
{
	StringView view = {
		.source = source,
		.length = length,
	};

	return view;
}

bool StringView_Equal(StringView first, StringView second)
{
	return 	first.length == second.length
		&&
		strncmp(first.source, second.source, first.length) == 0;
}

bool StringView_StartsWith(StringView string, StringView start)
{
	return strncmp(string.source, start.source, start.length) == 0;
}

bool StringView_EndsWith(StringView string, StringView end)
{
	if (end.length > string.length) {
		return false;
	}

	return StringView_Equal(
			end,
			StringView_Slice(
				string,
				string.length - end.length,
				string.length
				)
			);
}

bool StringView_Contains(StringView string, StringView find)
{
	return StringView_FindString(string, find).source != NULL;
}

size_t StringView_Count(StringView string, StringView find)
{
	size_t count = 0;
	while ((find = StringView_FindString(string, find)).source != NULL) {
		size_t offset = (uintptr_t) (find.source) - (uintptr_t) (string.source);
		string = (StringView) {string.source + offset, string.length - offset};
	}

	return count;
}

size_t StringView_FindStringOffset(StringView haystack, StringView needle)
{
	size_t offset = 0;
	size_t index = 0;

	while (offset < haystack.length) {
		while (index < needle.length && needle.source[index] == haystack.source[offset + index]) {
			index++;
		}
		if (index == needle.length) {
			return offset;
		}
		offset++;
	}

	return SIZE_MAX;
}

StringView StringView_FindString(StringView haystack, StringView needle)
{
	size_t offset = 0;
	size_t index = 0;

	while (offset < haystack.length) {
		while (index < needle.length && needle.source[index] == haystack.source[offset + index]) {
			index++;
		}
		if (index == needle.length) {
			return (StringView) {haystack.source + offset, needle.length};
		}
		offset++;
	}

	return (StringView) {NULL, 0};
}

StringView StringView_Slice(StringView string, size_t start, size_t end)
{
	if (end > string.length || start > string.length) {
		return (StringView) {NULL, 0};
	}

	StringView slice = {
		.length = end - start,
		.source = string.source + start,
	};

	return slice;
}

bool StringView_NextSplit(StringView* dest, StringView* source, StringView delim)
{
	if (source->length == 0) return false;

	size_t offset = StringView_FindStringOffset(*source, delim);
	if (offset == SIZE_MAX) {
		// No more delimiters, return entire source
		offset = source->length;
	}

	*dest   = StringView_Slice(*source, 0, offset);
	*source = StringView_Slice(*source, offset + delim.length, source->length);

	return true;
}

StringView StringView_StripLeft(StringView sv, StringView strip)
{
	while (StringView_StartsWith(sv, strip)) {
		sv = StringView_Slice(sv, strip.length, sv.length);
	}

	return sv;
}

StringView StringView_StripRight(StringView sv, StringView strip)
{
	while (StringView_EndsWith(sv, strip)) {
		sv = StringView_Slice(sv, 0, sv.length - strip.length);
	}

	return sv;
}


void StringView_Paste(char* destination, StringView source)
{
	memcpy(destination, source.source, source.length);
}

int StringView_ParseInt(StringView source)
{
	int value = 0;
	int sign = 1;

	switch (source.source[0]) {
	case '+':
		sign = 1;
		source.source++;
		source.length--;
		break;
	case '-':
		sign = -1;
		source.source++;
		source.length--;
		break;
	default:
		break;
	}

	while (source.length && isdigit(source.source[0])) {
		int digit = source.source[0] - '0';
		value *= 10;
		value += digit;

		source.source++;
		source.length--;
	}

	return value * sign;
}