34 lines
1.6 KiB
TypeScript
34 lines
1.6 KiB
TypeScript
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import { textIndex, processingPolicy } from "./text-processing.js";
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export type VariantSection = { start: number; end: number; text?: string };
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export type TextVariant = {
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source: string;
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sourceRevision: string;
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difficulty: string;
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sections: VariantSection[];
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};
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/** Canonical ranges never change when an earlier section expands or contracts.
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* Output offsets are appended in order, so annotations on ready text stay valid. */
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export function createVariant(source: string, sourceRevision: string, difficulty: string): TextVariant {
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const policy = processingPolicy({ chunkChars: 1400 });
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return { source, sourceRevision, difficulty, sections: textIndex(source).chunks(policy.chunkChars) };
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}
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export function parseVariant(raw: string): TextVariant | null {
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const value = JSON.parse(raw);
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return typeof value.source === "string" && Array.isArray(value.sections) ? value : null;
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}
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export function nextSection(variant: TextVariant) {
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return variant.sections.find((section) => section.text === undefined);
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}
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export function applySection(variant: TextVariant, start: number, end: number, text: string) {
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const section = nextSection(variant);
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if (!section || section.start !== start || section.end !== end) throw Error("Variant section changed");
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if (!text.trim() || text.length > 12000) throw Error("Invalid variant text");
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return { ...variant, sections: variant.sections.map((item) => (item === section ? { ...item, text } : item)) };
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}
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export function variantText(variant: TextVariant) {
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return variant.sections
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.filter((section) => section.text !== undefined)
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.map((section) => section.text)
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.join("\n\n");
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}
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