"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.pickFontFileForFallbackGeneration = pickFontFileForFallbackGeneration;
const next_font_error_1 = require("../next-font-error");
const NORMAL_WEIGHT = 400;
const BOLD_WEIGHT = 700;
/**
 * Convert the weight string to a number so it can be used for comparison.
 * Weights can be defined as a number, 'normal' or 'bold'. https://developer.mozilla.org/docs/Web/CSS/@font-face/font-weight
 */
function getWeightNumber(weight) {
    return weight === 'normal'
        ? NORMAL_WEIGHT
        : weight === 'bold'
            ? BOLD_WEIGHT
            : Number(weight);
}
/**
 * Get the distance from normal (400) weight for the provided weight.
 * If it's not a variable font we can just return the distance.
 * If it's a variable font we need to compare its weight range to 400.
 */
function getDistanceFromNormalWeight(weight) {
    if (!weight)
        return 0;
    // If it's a variable font the weight is defined with two numbers "100 900", rather than just one "400"
    const [firstWeight, secondWeight] = weight
        .trim()
        .split(/ +/)
        .map(getWeightNumber);
    if (Number.isNaN(firstWeight) || Number.isNaN(secondWeight)) {
        (0, next_font_error_1.nextFontError)(`Invalid weight value in src array: \`${weight}\`.\nExpected \`normal\`, \`bold\` or a number.`);
    }
    // If the weight doesn't have have a second value, it's not a variable font
    // If that's the case, just return the distance from normal weight
    if (!secondWeight) {
        return firstWeight - NORMAL_WEIGHT;
    }
    // Normal weight is within variable font range
    if (firstWeight <= NORMAL_WEIGHT && secondWeight >= NORMAL_WEIGHT) {
        return 0;
    }
    // Normal weight is outside variable font range
    // Return the distance of normal weight to the variable font range
    const firstWeightDistance = firstWeight - NORMAL_WEIGHT;
    const secondWeightDistance = secondWeight - NORMAL_WEIGHT;
    if (Math.abs(firstWeightDistance) < Math.abs(secondWeightDistance)) {
        return firstWeightDistance;
    }
    return secondWeightDistance;
}
/**
 * If multiple font files are provided for a font family, we need to pick one to use for the automatic fallback generation.
 * This function returns the font file that is most likely to be used for the bulk of the text on a page.
 *
 * There are some assumptions here about the text on a page when picking the font file:
 * - Most of the text will have normal weight, use the one closest to 400
 * - Most of the text will have normal style, prefer normal over italic
 * - If two font files have the same distance from normal weight, the thinner one will most likely be the bulk of the text
 */
function pickFontFileForFallbackGeneration(fontFiles) {
    return fontFiles.reduce((usedFontFile, currentFontFile) => {
        if (!usedFontFile)
            return currentFontFile;
        const usedFontDistance = getDistanceFromNormalWeight(usedFontFile.weight);
        const currentFontDistance = getDistanceFromNormalWeight(currentFontFile.weight);
        // Prefer normal style if they have the same weight
        if (usedFontDistance === currentFontDistance &&
            (typeof currentFontFile.style === 'undefined' ||
                currentFontFile.style === 'normal')) {
            return currentFontFile;
        }
        const absUsedDistance = Math.abs(usedFontDistance);
        const absCurrentDistance = Math.abs(currentFontDistance);
        // Use closest absolute distance to normal weight
        if (absCurrentDistance < absUsedDistance)
            return currentFontFile;
        // Prefer the thinner font if both have the same absolute distance from normal weight
        if (absUsedDistance === absCurrentDistance &&
            currentFontDistance < usedFontDistance) {
            return currentFontFile;
        }
        return usedFontFile;
    });
}
