/**
 * Module dependencies.
 */

const tty = require('tty');
const util = require('util');

/**
 * This is the Node.js implementation of `debug()`.
 */

exports.init = init;
exports.log = log;
exports.formatArgs = formatArgs;
exports.save = save;
exports.load = load;
exports.useColors = useColors;
exports.destroy = util.deprecate(
    () => {},
    'Instance method `debug.destroy()` is deprecated and no longer does anything. It will be removed in the next major version of `debug`.'
);

/**
 * Colors.
 */

exports.colors = [6, 2, 3, 4, 5, 1];

try {
    // Optional dependency (as in, doesn't need to be installed, NOT like optionalDependencies in package.json)
    // eslint-disable-next-line import/no-extraneous-dependencies
    const supportsColor = require('supports-color');

    if (supportsColor && (supportsColor.stderr || supportsColor).level >= 2) {
        exports.colors = [
            20,
            21,
            26,
            27,
            32,
            33,
            38,
            39,
            40,
            41,
            42,
            43,
            44,
            45,
            56,
            57,
            62,
            63,
            68,
            69,
            74,
            75,
            76,
            77,
            78,
            79,
            80,
            81,
            92,
            93,
            98,
            99,
            112,
            113,
            128,
            129,
            134,
            135,
            148,
            149,
            160,
            161,
            162,
            163,
            164,
            165,
            166,
            167,
            168,
            169,
            170,
            171,
            172,
            173,
            178,
            179,
            184,
            185,
            196,
            197,
            198,
            199,
            200,
            201,
            202,
            203,
            204,
            205,
            206,
            207,
            208,
            209,
            214,
            215,
            220,
            221
        ];
    }
} catch (error) {
    // Swallow - we only care if `supports-color` is available; it doesn't have to be.
}

/**
 * Build up the default `inspectOpts` object from the environment variables.
 *
 *   $ DEBUG_COLORS=no DEBUG_DEPTH=10 DEBUG_SHOW_HIDDEN=enabled node script.js
 */

exports.inspectOpts = Object.keys(process.env).filter(key => {
    return /^debug_/i.test(key);
}).reduce((obj, key) => {
    // Camel-case
    const prop = key
        .substring(6)
        .toLowerCase()
        .replace(/_([a-z])/g, (_, k) => {
            return k.toUpperCase();
        });

    // Coerce string value into JS value
    let val = process.env[key];
    if (/^(yes|on|true|enabled)$/i.test(val)) {
        val = true;
    } else if (/^(no|off|false|disabled)$/i.test(val)) {
        val = false;
    } else if (val === 'null') {
        val = null;
    } else {
        val = Number(val);
    }

    obj[prop] = val;
    return obj;
}, {});

/**
 * Is stdout a TTY? Colored output is enabled when `true`.
 */

function useColors() {
    return 'colors' in exports.inspectOpts ?
        Boolean(exports.inspectOpts.colors) :
        tty.isatty(process.stderr.fd);
}

/**
 * Adds ANSI color escape codes if enabled.
 *
 * @api public
 */

function formatArgs(args) {
    const {namespace: name, useColors} = this;

    if (useColors) {
        const c = this.color;
        const colorCode = '\u001B[3' + (c < 8 ? c : '8;5;' + c);
        const prefix = `  ${colorCode};1m${name} \u001B[0m`;

        args[0] = prefix + args[0].split('\n').join('\n' + prefix);
        args.push(colorCode + 'm+' + module.exports.humanize(this.diff) + '\u001B[0m');
    } else {
        args[0] = getDate() + name + ' ' + args[0];
    }
}

function getDate() {
    if (exports.inspectOpts.hideDate) {
        return '';
    }
    return new Date().toISOString() + ' ';
}

/**
 * Invokes `util.format()` with the specified arguments and writes to stderr.
 */

function log(...args) {
    return process.stderr.write(util.format(...args) + '\n');
}

/**
 * Save `namespaces`.
 *
 * @param {String} namespaces
 * @api private
 */
function save(namespaces) {
    if (namespaces) {
        process.env.DEBUG = namespaces;
    } else {
        // If you set a process.env field to null or undefined, it gets cast to the
        // string 'null' or 'undefined'. Just delete instead.
        delete process.env.DEBUG;
    }
}

/**
 * Load `namespaces`.
 *
 * @return {String} returns the previously persisted debug modes
 * @api private
 */

function load() {
    return process.env.DEBUG;
}

/**
 * Init logic for `debug` instances.
 *
 * Create a new `inspectOpts` object in case `useColors` is set
 * differently for a particular `debug` instance.
 */

function init(debug) {
    debug.inspectOpts = {};

    const keys = Object.keys(exports.inspectOpts);
    for (let i = 0; i < keys.length; i++) {
        debug.inspectOpts[keys[i]] = exports.inspectOpts[keys[i]];
    }
}

module.exports = require('./common')(exports);

const {formatters} = module.exports;

/**
 * Map %o to `util.inspect()`, all on a single line.
 */

formatters.o = function (v) {
    this.inspectOpts.colors = this.useColors;
    return util.inspect(v, this.inspectOpts)
        .split('\n')
        .map(str => str.trim())
        .join(' ');
};

/**
 * Map %O to `util.inspect()`, allowing multiple lines if needed.
 */

formatters.O = function (v) {
    this.inspectOpts.colors = this.useColors;
    return util.inspect(v, this.inspectOpts);
};