let's talk numbers

src/voice.ts

@@ -1,4 +1,4 @@
-
+import path from 'path';
 
 interface Voice {
     directory: string;
@@ -7,4 +7,167 @@ interface Voice {
 
 type Voices = { [name: string]: Voice };
 
+const LINES = {
+    NEGATIVE: 'negative',
+    POINT: 'point',
+    ZERO: 'zero',
+    ONE: 'one',
+    TWO: 'two',
+    THREE: 'three',
+    FOUR: 'four',
+    FIVE: 'five',
+    SIX: 'six',
+    SEVEN: 'seven',
+    EIGHT: 'eight',
+    NINE: 'nine',
+    TEN: 'ten',
+    ELEVEN: 'eleven',
+    TWELVE: 'twelve',
+    THIRTEEN: 'thirteen',
+    FIFTEEN: 'fifteen',
+    TEEN: 'teen',
+    TWENTY: 'twenty',
+    THIRTY: 'thirty',
+    FORTY: 'forty',
+    FIFTY: 'fifty',
+    SIXTY: 'sixty',
+    SEVENTY: 'seventy',
+    EIGHTY: 'eighty',
+    NINETY: 'ninety',
+    HUNDRED: 'hundred',
+    THOUSAND: 'thousand',
+    MILLION: 'million',
+    BILLION: 'billion',
+    TRILLION: 'trillion'
+}
+
+function formatNumber(num: number): string {
+    const parts = num.toString().split(".");
+    parts[0] = parts[0].replace(/\B(?=(\d{3})+(?!\d))/g, ",");
+    return parts.join(".");
+}
+
+function digitByDigit(str: string): string[] {
+    const tokens: string[] = [];
+    const input = str.replaceAll(',', '');
+    const map = [
+        LINES.ZERO,
+        LINES.ONE,
+        LINES.TWO,
+        LINES.THREE,
+        LINES.FOUR,
+        LINES.FIVE,
+        LINES.SIX,
+        LINES.SEVEN,
+        LINES.EIGHT,
+        LINES.NINE
+    ]
+    for (let i = 0; i < input.length; i++) {
+        tokens.push(map[parseInt(input.charAt(i))]);
+    }
+    return tokens;
+}
+
+function tens(str: string): string[] {
+    if (str === '0') {
+        return [LINES.ZERO];
+    }
+    const tokens: string[] = [];
+    const num = parseInt(str);
+    const map = {
+        '2': LINES.TWENTY,
+        '3': LINES.THIRTY,
+        '4': LINES.FORTY,
+        '5': LINES.FIFTY,
+        '6': LINES.SIXTY,
+        '7': LINES.SEVENTY,
+        '8': LINES.EIGHTY,
+        '9': LINES.NINETY
+    };
+    const ones = str.charAt(str.length - 1);
+    if (num === 0) {
+        return [];
+    }
+    else if (num >= 20) {
+        tokens.push(map[str.charAt(0)]);
+        if (ones !== '0') {
+            tokens.push(...digitByDigit(ones));
+        }
+    }
+    else if (num < 10) {
+        tokens.push(...digitByDigit(ones));
+    }
+    else {
+        const weirdoNumberMap = [
+            [LINES.TEN],
+            [LINES.ELEVEN],
+            [LINES.TWELVE],
+            [LINES.THIRTEEN],
+            [LINES.FOUR, LINES.TEEN],
+            [LINES.FIFTEEN],
+            [LINES.SIX, LINES.TEEN],
+            [LINES.SEVEN, LINES.TEEN],
+            [LINES.EIGHT, LINES.TEEN],
+            [LINES.NINE, LINES.TEEN],
+        ]
+        tokens.push(...weirdoNumberMap[num - 10]);
+    }
+    return tokens;
+}
+
+function hundreds(str: string): string[] {
+    const tokens: string[] = [];
+    if (str.length === 3 && str.charAt(0) !== '0') {
+        tokens.push(...digitByDigit(str.charAt(0)));
+        tokens.push(LINES.HUNDRED);
+        str = str.substring(1);
+    }
+    tokens.push(...tens(str));
+    return tokens;
+}
+
+function integer(str: string): string[] {
+    const tokens: string[] = [];
+    const numGroups = str.split(',');
+    const seperators = [LINES.TRILLION, LINES.BILLION, LINES.MILLION, LINES.THOUSAND];
+    if (numGroups.length > 5) {
+        return digitByDigit(str);
+    }
+    seperators.splice(0, seperators.length - numGroups.length + 1);
+    numGroups.forEach(g => {
+        if (g !== '000') {
+            tokens.push(...hundreds(g));
+        }
+        if (seperators.length === 0) {
+            return;
+        }
+        const sep = seperators.shift();
+        if (g !== '000') {
+            tokens.push(sep);
+        }
+    });
+    return tokens;
+}
+
+function voiceLines(voice: Voice, num: number): string[] {
+    if (Math.abs(num) > 999999999999999 || isNaN(num)) {
+        return [];
+    }
+    const tokens: string[] = [];
+    const str = formatNumber(num);
+    const parts = str.split('.');
+    if (parts[0].startsWith('-')) {
+        tokens.push(LINES.NEGATIVE);
+        parts[0] = parts[0].substring(1);
+    }
+    tokens.push(...integer(parts[0]));
+    if (parts.length > 1) {
+        tokens.push(LINES.POINT);
+        tokens.push(...digitByDigit(parts[1]));
+    }
+    return tokens.map(l => path.join(voice.directory, `${l}.${voice.extension}`));
+}
+
+export default voiceLines;
+export { voiceLines };
 export type { Voice, Voices };