/*
 * Copyright (C) 2019- TeraTerm Project
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdlib.h>
#include <stdio.h>

#include "unicode.h"

/**
 *	East_Asian_Width 参考特性 取得
 *
 *	@retval	'F'		Fullwidth 全角
 *	@retval	'H'		Halfwidth 半角
 *	@retval	'W'		Wide 広
 *	@retval	'n'		Na,Narrow 狭
 *	@retval	'A'		Ambiguous 曖昧
 *					文脈によって文字幅が異なる文字。
 *					東アジアの組版とそれ以外の組版の両方に出現し、
 *					東アジアの従来文字コードではいわゆる全角として扱われることがある。
 *					ギリシア文字やキリル文字など。
 *	@retval	'N'		Neutral 中立
 *					東アジアの組版には通常出現せず、全角でも半角でもない。アラビア文字など。
 */
char UnicodeGetWidthProperty(unsigned long u32)
{
	typedef struct {
		unsigned long code_from;
		unsigned long code_to;
		char property;
	} east_asian_width_map_t;
	// テーブルに入っていない場合は H
	const static east_asian_width_map_t east_asian_width_map[] = {
#include "unicode_asian_width.tbl"
	};
	const east_asian_width_map_t *table = east_asian_width_map;
	const size_t table_size = _countof(east_asian_width_map);
	char result;

	// テーブル外チェック
	if (u32 < east_asian_width_map[0].code_from) {
		return 'H';
	}
	if (east_asian_width_map[table_size-1].code_to < u32) {
		return 'H';
	}

	// テーブル検索
	result = 'H';
	size_t low = 0;
	size_t high = table_size - 1;
	while (low < high) {
		size_t mid = (low + high) / 2;
		if (table[mid].code_from <= u32 && u32 <= table[mid].code_to) {
			result = table[mid].property;
			break;
		} else if (table[mid].code_to < u32) {
			low = mid + 1;
		} else {
			high = mid;
		}
	}

	return result;
}

typedef struct {
	unsigned long code_from;
	unsigned long code_to;
} UnicodeTable_t;

/**
 * u32がテーブルのデータに含まれているか調べる
 */
static int UnicodeSimpleSearchTable(
	const UnicodeTable_t *table, size_t table_size,
	unsigned long u32)
{
	if (u32 < table[0].code_from) {
		return 0;
	}
	if (u32 > table[table_size-1].code_to) {
		return 0;
	}
	size_t low = 0;
	size_t high = table_size - 1;
	while (low <= high) {
		size_t mid = (low + high) / 2;
		if (table[mid].code_from <= u32 && u32 <= table[mid].code_to) {
			return 1;
		} else if (table[mid].code_to < u32) {
			low = mid + 1;
		} else {
			high = mid - 1;
		}
	}
	// テーブルの範囲外
	return 0;
}

/*
 * 結合文字か検査する
 *		EMOJI MODIFIER も結合文字として扱う
 *
 *	@retval	0		結合文字ではない
 *	@retval	1		結合文字である
 */
int UnicodeIsCombiningCharacter(unsigned long u32)
{
	const static UnicodeTable_t CombiningCharacterList[] = {
#include "unicode_combine.tbl"
	};
	return UnicodeSimpleSearchTable(
		CombiningCharacterList, _countof(CombiningCharacterList),
		u32);
}


int UnicodeIsEmoji(unsigned long u32)
{
	const static UnicodeTable_t EmojiList[] = {
#include "unicode_emoji.tbl"
	};
	return UnicodeSimpleSearchTable(
		EmojiList, _countof(EmojiList),
		u32);
}

/**
 *	異体字セレクタかチェックする
 *
 *	@retval	0		異体字セレクタではない
 *	@retval	1		異体字セレクタである
 */
int UnicodeIsVariationSelector(unsigned long u32)
{
	if ((0x00180b <= u32 && u32 <= 0x00180d) ||	// FVS (Mongolian Free Variation Selector)
		(0x00fe00 <= u32 && u32 <= 0x00fe0f) ||	// SVS VS1〜VS16
		(0x0e0100 <= u32 && u32 <= 0x0e01ef))	// IVS VS17〜VS256
	{
		return 1;
	}
	return 0;
}


#if 0
int main(int, char *[])
{
	static const unsigned long codes[] = {
#if 0
		0, 1, 0x7f,
		0x80,
		0x0e00ff,
		0x0e0100,
		0x10fffd,
#endif
		0x10fffe,
	};

	for (size_t i = 0; i < _countof(codes); i++) {
		unsigned long code = codes[i];
		printf("U+%06lx %c\n", code, UnicodeGetWidthProperty(code));
	}
	return 0;
}
#endif

//
// Unicode Combining Character Support
//
#include "uni_combining.map"

unsigned short UnicodeGetPrecomposedChar(int start_index, unsigned short first_code, unsigned short code)
{
	const combining_map_t *table = mapCombiningToPrecomposed;
	int tmax = _countof(mapCombiningToPrecomposed);
	unsigned short result = 0;
	int i;

	for (i = start_index ; i < tmax ; i++) {
		if (table[i].first_code != first_code) { // 1文字目が異なるなら、以降はもう調べなくてよい。
			break;
		}

		if (table[i].second_code == code) {
			result = table[i].precomposed;
			break;
		}
	}

	return (result);
}

int UnicodeGetIndexOfCombiningFirstCode(unsigned short code)
{
	const combining_map_t *table = mapCombiningToPrecomposed;
	int tmax = _countof(mapCombiningToPrecomposed);
	int low, mid, high;
	int index = -1;

	low = 0;
	high = tmax - 1;

	// binary search
	while (low < high) {
		mid = (low + high) / 2;
		if (table[mid].first_code < code) {
			low = mid + 1;
		} else {
			high = mid;
		}
	}

	if (table[low].first_code == code) {
		while (low >= 0 && table[low].first_code == code) {
			index = low;
			low--;
		}
	}

	return (index);
}

/**
 *	Unicodeの結合処理を行う
 *	@param[in]	first_code
 *	@param[in]	code
 *	@retval		0		結合できない
 *	@retval		以外	結合したUnicode
 */
unsigned short UnicodeCombining(unsigned short first_code, unsigned short code)
{
	int first_code_index = UnicodeGetIndexOfCombiningFirstCode(first_code);
	if (first_code_index == -1) {
		return 0;
	}
	unsigned short cset = UnicodeGetPrecomposedChar(first_code_index, first_code, code);
	return cset;
}
