Intlayer

import { splitTextByLines } from '@intlayer/chokidar'; import { type ChunkLineResult, chunkText } from './calculateChunks'; export interface ChunkMapping { baseChunk: ChunkLineResult; updatedChunk: ChunkLineResult | null; // null if the chunk was deleted hasChanges: boolean; } /** * Maps chunks from base file to corresponding chunks in updated file, * handling insertions, deletions, and modifications properly. */ export const mapChunksBetweenFiles = ( baseFileContent: string, updatedFileContent: string, maxCharsPerChunk: number = 800, changedLines?: number[] ): ChunkMapping[] => { const baseChunks = chunkText(baseFileContent, maxCharsPerChunk, 0); const baseLines = splitTextByLines(baseFileContent); const updatedLines = splitTextByLines(updatedFileContent); // Create a simple line mapping using LCS (Longest Common Subsequence) approach const lineMapping = createLineMapping(baseLines, updatedLines); return baseChunks.map((baseChunk): ChunkMapping => { // Map the base chunk's line range to the updated file const mappedRange = mapLineRange( baseChunk.lineStart, baseChunk.lineLength, lineMapping ); if (!mappedRange) { // This chunk was completely deleted return { baseChunk, updatedChunk: null, hasChanges: true, }; } // Create the corresponding chunk in the updated file const updatedChunk: ChunkLineResult = { lineStart: mappedRange.start, lineLength: mappedRange.length, charStart: 0, // Will be calculated when needed charLength: 0, // Will be calculated when needed content: extractLinesFromRange( updatedLines, mappedRange.start, mappedRange.length ), }; // Calculate character positions updatedChunk.charStart = getCharStartForLine( updatedFileContent, updatedChunk.lineStart ); updatedChunk.charLength = updatedChunk.content.length; // Determine if this chunk has changes const hasChanges = determineIfChunkHasChanges( baseChunk, updatedChunk, changedLines ); return { baseChunk, updatedChunk, hasChanges, }; }); }; /** * Creates a mapping between line numbers in base file and updated file * Returns a map where key = base line number, value = updated line number (or null if deleted) */ const createLineMapping = ( baseLines: string[], updatedLines: string[] ): Map<number, number | null> => { const mapping = new Map<number, number | null>(); // Use a simple diff algorithm (similar to Myers algorithm but simplified) const dp: number[][] = Array(baseLines.length + 1) .fill(null) .map(() => Array(updatedLines.length + 1).fill(0)); // Fill the DP table for (let i = 1; i <= baseLines.length; i++) { for (let j = 1; j <= updatedLines.length; j++) { if (baseLines[i - 1] === updatedLines[j - 1]) { dp[i][j] = dp[i - 1][j - 1] + 1; } else { dp[i][j] = Math.max(dp[i - 1][j], dp[i][j - 1]); } } } // Backtrack to create the mapping let i = baseLines.length; let j = updatedLines.length; while (i > 0 || j > 0) { if (i > 0 && j > 0 && baseLines[i - 1] === updatedLines[j - 1]) { // Lines match mapping.set(i - 1, j - 1); i--; j--; } else if (i > 0 && (j === 0 || dp[i - 1][j] >= dp[i][j - 1])) { // Line was deleted from base mapping.set(i - 1, null); i--; } else { // Line was added to updated (no mapping needed for base) j--; } } return mapping; }; /** * Maps a line range from base file to updated file using the line mapping */ const mapLineRange = ( baseStart: number, baseLength: number, lineMapping: Map<number, number | null> ): { start: number; length: number } | null => { const mappedLines: number[] = []; for (let i = baseStart; i < baseStart + baseLength; i++) { const mappedLine = lineMapping.get(i); if (mappedLine !== null && mappedLine !== undefined) { mappedLines.push(mappedLine); } } if (mappedLines.length === 0) { return null; // All lines were deleted } // Find the continuous range in the mapped lines mappedLines.sort((a, b) => a - b); const start = mappedLines[0]; const end = mappedLines[mappedLines.length - 1]; return { start, length: end - start + 1, }; }; /** * Extracts lines from a range in the lines array */ const extractLinesFromRange = ( lines: string[], start: number, length: number ): string => { const endIndex = Math.min(start + length, lines.length); return lines.slice(start, endIndex).join(''); }; /** * Gets the character position where a line starts in the text */ const getCharStartForLine = (text: string, lineNumber: number): number => { const lines = splitTextByLines(text); let charStart = 0; for (let i = 0; i < Math.min(lineNumber, lines.length); i++) { charStart += lines[i].length; } return charStart; }; /** * Determines if a chunk has changes based on git changed lines or content comparison */ const determineIfChunkHasChanges = ( baseChunk: ChunkLineResult, updatedChunk: ChunkLineResult, changedLines?: number[] ): boolean => { // If we have git changed lines, use them for precise detection if (changedLines && changedLines.length > 0) { return changedLines.some( (line) => line >= updatedChunk.lineStart && line < updatedChunk.lineStart + updatedChunk.lineLength ); } // Fallback to content comparison return baseChunk.content !== updatedChunk.content; };