Japanese util refactor (#510)

* Convert mixed japanese.js to utility class

* Copy functions from bg/js/japanese.js into mixed/js/japanese.js

* Remove bg/js/japanese.js

* Make wanakana dependency optional

* Update tests

1 files changed, 0 insertions, 426 deletions

diff --git a/ext/bg/js/japanese.js b/ext/bg/js/japanese.js
deleted file mode 100644
index ac81acb5..00000000
--- a/ext/bg/js/japanese.js
+++ /dev/null
@@ -1,426 +0,0 @@
-/*
- * Copyright (C) 2016-2020  Yomichan Authors
- *
- * 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 3 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, see <https://www.gnu.org/licenses/>.
- */
-
-/* global
- * jp
- * wanakana
- */
-
-(() => {
-    const HALFWIDTH_KATAKANA_MAPPING = new Map([
-        ['ｦ', 'ヲヺ-'],
-        ['ｧ', 'ァ--'],
-        ['ｨ', 'ィ--'],
-        ['ｩ', 'ゥ--'],
-        ['ｪ', 'ェ--'],
-        ['ｫ', 'ォ--'],
-        ['ｬ', 'ャ--'],
-        ['ｭ', 'ュ--'],
-        ['ｮ', 'ョ--'],
-        ['ｯ', 'ッ--'],
-        ['ｰ', 'ー--'],
-        ['ｱ', 'ア--'],
-        ['ｲ', 'イ--'],
-        ['ｳ', 'ウヴ-'],
-        ['ｴ', 'エ--'],
-        ['ｵ', 'オ--'],
-        ['ｶ', 'カガ-'],
-        ['ｷ', 'キギ-'],
-        ['ｸ', 'クグ-'],
-        ['ｹ', 'ケゲ-'],
-        ['ｺ', 'コゴ-'],
-        ['ｻ', 'サザ-'],
-        ['ｼ', 'シジ-'],
-        ['ｽ', 'スズ-'],
-        ['ｾ', 'セゼ-'],
-        ['ｿ', 'ソゾ-'],
-        ['ﾀ', 'タダ-'],
-        ['ﾁ', 'チヂ-'],
-        ['ﾂ', 'ツヅ-'],
-        ['ﾃ', 'テデ-'],
-        ['ﾄ', 'トド-'],
-        ['ﾅ', 'ナ--'],
-        ['ﾆ', 'ニ--'],
-        ['ﾇ', 'ヌ--'],
-        ['ﾈ', 'ネ--'],
-        ['ﾉ', 'ノ--'],
-        ['ﾊ', 'ハバパ'],
-        ['ﾋ', 'ヒビピ'],
-        ['ﾌ', 'フブプ'],
-        ['ﾍ', 'ヘベペ'],
-        ['ﾎ', 'ホボポ'],
-        ['ﾏ', 'マ--'],
-        ['ﾐ', 'ミ--'],
-        ['ﾑ', 'ム--'],
-        ['ﾒ', 'メ--'],
-        ['ﾓ', 'モ--'],
-        ['ﾔ', 'ヤ--'],
-        ['ﾕ', 'ユ--'],
-        ['ﾖ', 'ヨ--'],
-        ['ﾗ', 'ラ--'],
-        ['ﾘ', 'リ--'],
-        ['ﾙ', 'ル--'],
-        ['ﾚ', 'レ--'],
-        ['ﾛ', 'ロ--'],
-        ['ﾜ', 'ワ--'],
-        ['ﾝ', 'ン--']
-    ]);
-
-    const ITERATION_MARK_CODE_POINT = 0x3005;
-
-    const HIRAGANA_SMALL_TSU_CODE_POINT = 0x3063;
-    const KATAKANA_SMALL_TSU_CODE_POINT = 0x30c3;
-    const KANA_PROLONGED_SOUND_MARK_CODE_POINT = 0x30fc;
-
-    // Existing functions
-
-    const isCodePointKanji = jp.isCodePointKanji;
-    const isStringEntirelyKana = jp.isStringEntirelyKana;
-
-
-    // Conversion functions
-
-    function convertKatakanaToHiragana(text) {
-        let result = '';
-        for (const c of text) {
-            if (wanakana.isKatakana(c)) {
-                result += wanakana.toHiragana(c);
-            } else {
-                result += c;
-            }
-        }
-
-        return result;
-    }
-
-    function convertHiraganaToKatakana(text) {
-        let result = '';
-        for (const c of text) {
-            if (wanakana.isHiragana(c)) {
-                result += wanakana.toKatakana(c);
-            } else {
-                result += c;
-            }
-        }
-
-        return result;
-    }
-
-    function convertToRomaji(text) {
-        return wanakana.toRomaji(text);
-    }
-
-    function convertReading(expression, reading, readingMode) {
-        switch (readingMode) {
-            case 'hiragana':
-                return convertKatakanaToHiragana(reading);
-            case 'katakana':
-                return convertHiraganaToKatakana(reading);
-            case 'romaji':
-                if (reading) {
-                    return convertToRomaji(reading);
-                } else {
-                    if (isStringEntirelyKana(expression)) {
-                        return convertToRomaji(expression);
-                    }
-                }
-                return reading;
-            case 'none':
-                return '';
-            default:
-                return reading;
-        }
-    }
-
-    function convertNumericToFullWidth(text) {
-        let result = '';
-        for (const char of text) {
-            let c = char.codePointAt(0);
-            if (c >= 0x30 && c <= 0x39) { // ['0', '9']
-                c += 0xff10 - 0x30; // 0xff10 = '0' full width
-                result += String.fromCodePoint(c);
-            } else {
-                result += char;
-            }
-        }
-        return result;
-    }
-
-    function convertHalfWidthKanaToFullWidth(text, sourceMap=null) {
-        let result = '';
-
-        // This function is safe to use charCodeAt instead of codePointAt, since all
-        // the relevant characters are represented with a single UTF-16 character code.
-        for (let i = 0, ii = text.length; i < ii; ++i) {
-            const c = text[i];
-            const mapping = HALFWIDTH_KATAKANA_MAPPING.get(c);
-            if (typeof mapping !== 'string') {
-                result += c;
-                continue;
-            }
-
-            let index = 0;
-            switch (text.charCodeAt(i + 1)) {
-                case 0xff9e: // dakuten
-                    index = 1;
-                    break;
-                case 0xff9f: // handakuten
-                    index = 2;
-                    break;
-            }
-
-            let c2 = mapping[index];
-            if (index > 0) {
-                if (c2 === '-') { // invalid
-                    index = 0;
-                    c2 = mapping[0];
-                } else {
-                    ++i;
-                }
-            }
-
-            if (sourceMap !== null && index > 0) {
-                sourceMap.combine(result.length, 1);
-            }
-            result += c2;
-        }
-
-        return result;
-    }
-
-    function convertAlphabeticToKana(text, sourceMap=null) {
-        let part = '';
-        let result = '';
-
-        for (const char of text) {
-            // Note: 0x61 is the character code for 'a'
-            let c = char.codePointAt(0);
-            if (c >= 0x41 && c <= 0x5a) { // ['A', 'Z']
-                c += (0x61 - 0x41);
-            } else if (c >= 0x61 && c <= 0x7a) { // ['a', 'z']
-                // NOP; c += (0x61 - 0x61);
-            } else if (c >= 0xff21 && c <= 0xff3a) { // ['A', 'Z'] fullwidth
-                c += (0x61 - 0xff21);
-            } else if (c >= 0xff41 && c <= 0xff5a) { // ['a', 'z'] fullwidth
-                c += (0x61 - 0xff41);
-            } else if (c === 0x2d || c === 0xff0d) { // '-' or fullwidth dash
-                c = 0x2d; // '-'
-            } else {
-                if (part.length > 0) {
-                    result += convertAlphabeticPartToKana(part, sourceMap, result.length);
-                    part = '';
-                }
-                result += char;
-                continue;
-            }
-            part += String.fromCodePoint(c);
-        }
-
-        if (part.length > 0) {
-            result += convertAlphabeticPartToKana(part, sourceMap, result.length);
-        }
-        return result;
-    }
-
-    function convertAlphabeticPartToKana(text, sourceMap, sourceMapStart) {
-        const result = wanakana.toHiragana(text);
-
-        // Generate source mapping
-        if (sourceMap !== null) {
-            let i = 0;
-            let resultPos = 0;
-            const ii = text.length;
-            while (i < ii) {
-                // Find smallest matching substring
-                let iNext = i + 1;
-                let resultPosNext = result.length;
-                while (iNext < ii) {
-                    const t = wanakana.toHiragana(text.substring(0, iNext));
-                    if (t === result.substring(0, t.length)) {
-                        resultPosNext = t.length;
-                        break;
-                    }
-                    ++iNext;
-                }
-
-                // Merge characters
-                const removals = iNext - i - 1;
-                if (removals > 0) {
-                    sourceMap.combine(sourceMapStart, removals);
-                }
-                ++sourceMapStart;
-
-                // Empty elements
-                const additions = resultPosNext - resultPos - 1;
-                for (let j = 0; j < additions; ++j) {
-                    sourceMap.insert(sourceMapStart, 0);
-                    ++sourceMapStart;
-                }
-
-                i = iNext;
-                resultPos = resultPosNext;
-            }
-        }
-
-        return result;
-    }
-
-
-    // Furigana distribution
-
-    function distributeFurigana(expression, reading) {
-        const fallback = [{furigana: reading, text: expression}];
-        if (!reading) {
-            return fallback;
-        }
-
-        let isAmbiguous = false;
-        const segmentize = (reading2, groups) => {
-            if (groups.length === 0 || isAmbiguous) {
-                return [];
-            }
-
-            const group = groups[0];
-            if (group.mode === 'kana') {
-                if (convertKatakanaToHiragana(reading2).startsWith(convertKatakanaToHiragana(group.text))) {
-                    const readingLeft = reading2.substring(group.text.length);
-                    const segs = segmentize(readingLeft, groups.splice(1));
-                    if (segs) {
-                        return [{text: group.text, furigana: ''}].concat(segs);
-                    }
-                }
-            } else {
-                let foundSegments = null;
-                for (let i = reading2.length; i >= group.text.length; --i) {
-                    const readingUsed = reading2.substring(0, i);
-                    const readingLeft = reading2.substring(i);
-                    const segs = segmentize(readingLeft, groups.slice(1));
-                    if (segs) {
-                        if (foundSegments !== null) {
-                            // more than one way to segmentize the tail, mark as ambiguous
-                            isAmbiguous = true;
-                            return null;
-                        }
-                        foundSegments = [{text: group.text, furigana: readingUsed}].concat(segs);
-                    }
-                    // there is only one way to segmentize the last non-kana group
-                    if (groups.length === 1) {
-                        break;
-                    }
-                }
-                return foundSegments;
-            }
-        };
-
-        const groups = [];
-        let modePrev = null;
-        for (const c of expression) {
-            const codePoint = c.codePointAt(0);
-            const modeCurr = isCodePointKanji(codePoint) || codePoint === ITERATION_MARK_CODE_POINT ? 'kanji' : 'kana';
-            if (modeCurr === modePrev) {
-                groups[groups.length - 1].text += c;
-            } else {
-                groups.push({mode: modeCurr, text: c});
-                modePrev = modeCurr;
-            }
-        }
-
-        const segments = segmentize(reading, groups);
-        if (segments && !isAmbiguous) {
-            return segments;
-        }
-        return fallback;
-    }
-
-    function distributeFuriganaInflected(expression, reading, source) {
-        const output = [];
-
-        let stemLength = 0;
-        const shortest = Math.min(source.length, expression.length);
-        const sourceHiragana = convertKatakanaToHiragana(source);
-        const expressionHiragana = convertKatakanaToHiragana(expression);
-        while (stemLength < shortest && sourceHiragana[stemLength] === expressionHiragana[stemLength]) {
-            ++stemLength;
-        }
-        const offset = source.length - stemLength;
-
-        const stemExpression = source.substring(0, source.length - offset);
-        const stemReading = reading.substring(
-            0,
-            offset === 0 ? reading.length : reading.length - expression.length + stemLength
-        );
-        for (const segment of distributeFurigana(stemExpression, stemReading)) {
-            output.push(segment);
-        }
-
-        if (stemLength !== source.length) {
-            output.push({text: source.substring(stemLength), furigana: ''});
-        }
-
-        return output;
-    }
-
-
-    // Miscellaneous
-
-    function collapseEmphaticSequences(text, fullCollapse, sourceMap=null) {
-        let result = '';
-        let collapseCodePoint = -1;
-        const hasSourceMap = (sourceMap !== null);
-        for (const char of text) {
-            const c = char.codePointAt(0);
-            if (
-                c === HIRAGANA_SMALL_TSU_CODE_POINT ||
-                c === KATAKANA_SMALL_TSU_CODE_POINT ||
-                c === KANA_PROLONGED_SOUND_MARK_CODE_POINT
-            ) {
-                if (collapseCodePoint !== c) {
-                    collapseCodePoint = c;
-                    if (!fullCollapse) {
-                        result += char;
-                        continue;
-                    }
-                }
-            } else {
-                collapseCodePoint = -1;
-                result += char;
-                continue;
-            }
-
-            if (hasSourceMap) {
-                sourceMap.combine(Math.max(0, result.length - 1), 1);
-            }
-        }
-        return result;
-    }
-
-
-    // Exports
-
-    Object.assign(jp, {
-        convertKatakanaToHiragana,
-        convertHiraganaToKatakana,
-        convertToRomaji,
-        convertReading,
-        convertNumericToFullWidth,
-        convertHalfWidthKanaToFullWidth,
-        convertAlphabeticToKana,
-        distributeFurigana,
-        distributeFuriganaInflected,
-        collapseEmphaticSequences
-    });
-})();