"use strict"

export function insertionPointReturnValue(pt: number) {
    return ((-pt) - 1)
}

export function binarySearch(array: number[], sought: number) {

    let lower = 0
    let upper = array.length - 1

    while (lower <= upper) {
        let idx = Math.floor((lower + upper) / 2)
        const value = array[idx]

        if (value === sought) {
            return idx;
        }

        if (lower === upper) {
            const insertionPoint = (value < sought) ? idx + 1 : idx
            return insertionPointReturnValue(insertionPoint)
        }

        if (sought > value) {
            lower = idx + 1;
        } else if (sought < value) {
            upper = idx - 1;
        }
    }
}

export function getLineStartPositions(text: string) {
    const lineStartPositions = [0];
    for (var i = 0; i < text.length; i++) {
        const c = text[i];

        if (c === '\r') {
            // Check for Windows encoding, otherwise we are old Mac
            if (i + 1 < text.length && text[i + 1] == '\n') {
                i++;
            }

            lineStartPositions.push(i + 1);
        } else if (c === '\n'){
            lineStartPositions.push(i + 1);
        }
    }

    return lineStartPositions;
}

export function getPosition(pos: number, lineStartPositions: number[]){
    let line = binarySearch(lineStartPositions, pos)

    if (line < 0){
        const insertionPoint = -1 * line - 1;
        line = insertionPoint - 1;
    }

    return {line, column: pos - lineStartPositions[line]}
}