/*---------------------------------------------------------------------------------------------

* Copyright (c) Microsoft Corporation. All rights reserved.

* Licensed under the MIT License. See License.txt in the project root for license information.

*--------------------------------------------------------------------------------------------*/

import { DiffHunk, DiffLine, parseDiffHunk } from './diffHunk';

/**

* Line position in a git diff is 1 based, except for the case when the original or changed file have

* no content, in which case it is 0. Normalize the position to be zero based.

* @param line The line in a file from the diff header

*/

export function getZeroBased(line: number): number {

if (line === undefined || line === 0) {

return 0;

}

return line - 1;

}

export function getDiffLineByPosition(diffHunks: DiffHunk[], diffLineNumber: number): DiffLine | undefined {

for (let i = 0; i < diffHunks.length; i++) {

const diffHunk = diffHunks[i];

for (let j = 0; j < diffHunk.diffLines.length; j++) {

if (diffHunk.diffLines[j].positionInHunk === diffLineNumber) {

return diffHunk.diffLines[j];

}

}

}

return undefined;

}

export function mapOldPositionToNew(patch: string, line: number): number {

const diffReader = parseDiffHunk(patch);

let diffIter = diffReader.next();

let delta = 0;

while (!diffIter.done) {

const diffHunk: DiffHunk = diffIter.value;

if (diffHunk.oldLineNumber > line) {

// No-op

} else if (diffHunk.oldLineNumber + diffHunk.oldLength - 1 < line) {

delta += diffHunk.newLength - diffHunk.oldLength;

} else {

delta += diffHunk.newLength - diffHunk.oldLength;

return line + delta;

}

diffIter = diffReader.next();

}

return line + delta;

}

export function mapNewPositionToOld(patch: string, line: number): number {

const diffReader = parseDiffHunk(patch);

let diffIter = diffReader.next();

let delta = 0;

while (!diffIter.done) {

const diffHunk: DiffHunk = diffIter.value;

if (diffHunk.newLineNumber > line) {

// No-op

} else if (diffHunk.newLineNumber + diffHunk.newLength - 1 < line) {

delta += diffHunk.oldLength - diffHunk.newLength;

} else {

delta += diffHunk.oldLength - diffHunk.newLength;

return line + delta;

}

diffIter = diffReader.next();

}

return line + delta;

}