83 lines
2.8 KiB
JavaScript
83 lines
2.8 KiB
JavaScript
/* global module */
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/**
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* 终端播报长度配置拆成“总量”和“单段”两层：
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* 1. 总量决定一轮回答最多取多少正文；
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* 2. 单段决定每次送给 TTS 的请求大小，用来压低首段等待时延；
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* 3. 单段限制必须保守落在 gateway 当前长度校验之内；
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* 4. “分片长度”只控制单段字符窗口，实际仍会再受 UTF-8 byte 上限兜底。
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*/
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const DEFAULT_TTS_SPEAKABLE_MAX_CHARS = 500;
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const MIN_TTS_SPEAKABLE_MAX_CHARS = 120;
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const MAX_TTS_SPEAKABLE_MAX_CHARS = 1200;
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const DEFAULT_TTS_SEGMENT_MAX_CHARS = 80;
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const MIN_TTS_SEGMENT_MAX_CHARS = 40;
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const MAX_TTS_SEGMENT_MAX_CHARS = 200;
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const TTS_SEGMENT_MAX_CHARS = DEFAULT_TTS_SEGMENT_MAX_CHARS;
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const TTS_SEGMENT_MAX_UTF8_BYTES = DEFAULT_TTS_SEGMENT_MAX_CHARS * 3;
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function normalizeTtsSpeakableMaxChars(value) {
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const parsed = Number(value);
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if (!Number.isFinite(parsed)) {
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return DEFAULT_TTS_SPEAKABLE_MAX_CHARS;
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}
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const normalized = Math.round(parsed);
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if (normalized < MIN_TTS_SPEAKABLE_MAX_CHARS) {
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return MIN_TTS_SPEAKABLE_MAX_CHARS;
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}
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if (normalized > MAX_TTS_SPEAKABLE_MAX_CHARS) {
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return MAX_TTS_SPEAKABLE_MAX_CHARS;
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}
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return normalized;
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}
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function normalizeTtsSegmentMaxChars(value) {
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const parsed = Number(value);
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if (!Number.isFinite(parsed)) {
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return DEFAULT_TTS_SEGMENT_MAX_CHARS;
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}
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const normalized = Math.round(parsed);
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if (normalized < MIN_TTS_SEGMENT_MAX_CHARS) {
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return MIN_TTS_SEGMENT_MAX_CHARS;
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}
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if (normalized > MAX_TTS_SEGMENT_MAX_CHARS) {
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return MAX_TTS_SEGMENT_MAX_CHARS;
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}
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return normalized;
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}
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/**
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* 总量截断只负责控制“这一轮最多保留多少正文”，并不直接对应单次网关请求。
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* 对中文按 3 bytes/字估算，可让 500 字正文完整进入后续分段流程。
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*/
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function resolveTtsSpeakableUtf8ByteLimit(maxChars) {
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const normalized = normalizeTtsSpeakableMaxChars(maxChars);
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return Math.max(TTS_SEGMENT_MAX_UTF8_BYTES, Math.min(normalized * 3, MAX_TTS_SPEAKABLE_MAX_CHARS * 3));
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}
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/**
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* 单段 byte 限制始终卡在安全阈值内：
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* 1. 默认 80 字对应 240 bytes；
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* 2. 即使用户把分片长度调大，最终也不会超过 360 bytes；
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* 3. 这样可避免单段再次撞到网关 450 bytes 的校验。
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*/
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function resolveTtsSegmentUtf8ByteLimit(maxChars) {
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const normalized = normalizeTtsSegmentMaxChars(maxChars);
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return Math.max(TTS_SEGMENT_MAX_UTF8_BYTES, Math.min(normalized * 3, 360));
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}
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module.exports = {
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DEFAULT_TTS_SPEAKABLE_MAX_CHARS,
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MIN_TTS_SPEAKABLE_MAX_CHARS,
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MAX_TTS_SPEAKABLE_MAX_CHARS,
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DEFAULT_TTS_SEGMENT_MAX_CHARS,
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MIN_TTS_SEGMENT_MAX_CHARS,
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MAX_TTS_SEGMENT_MAX_CHARS,
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TTS_SEGMENT_MAX_CHARS,
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TTS_SEGMENT_MAX_UTF8_BYTES,
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normalizeTtsSpeakableMaxChars,
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normalizeTtsSegmentMaxChars,
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resolveTtsSpeakableUtf8ByteLimit,
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resolveTtsSegmentUtf8ByteLimit
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};
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