/*
The original version of this code is taken from Douglas Crockford's json2.js:
https://github.com/douglascrockford/JSON-js/blob/master/json2.js

I made some modifications to ensure a canonical output.
*/

function f(n) {
    // Format integers to have at least two digits.
    return n < 10 ? '0' + n : n;
}

var cx = /[\u0000\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
    escapable = /[\\\"\x00-\x1f\x7f-\x9f\u00ad\u0600-\u0604\u070f\u17b4\u17b5\u200c-\u200f\u2028-\u202f\u2060-\u206f\ufeff\ufff0-\uffff]/g,
    gap,
    indent,
    meta = {    // table of character substitutions
        '\b': '\\b',
        '\t': '\\t',
        '\n': '\\n',
        '\f': '\\f',
        '\r': '\\r',
        '"' : '\\"',
        '\\': '\\\\'
    },
    rep;


function quote(string) {

// If the string contains no control characters, no quote characters, and no
// backslash characters, then we can safely slap some quotes around it.
// Otherwise we must also replace the offending characters with safe escape
// sequences.

    escapable.lastIndex = 0;
    return escapable.test(string) ? '"' + string.replace(escapable, function (a) {
        var c = meta[a];
        return typeof c === 'string'
            ? c
            : '\\u' + ('0000' + a.charCodeAt(0).toString(16)).slice(-4);
    }) + '"' : '"' + string + '"';
}


function str(key, holder) {

// Produce a string from holder[key].

    var i,          // The loop counter.
        k,          // The member key.
        v,          // The member value.
        length,
        mind = gap,
        partial,
        value = holder[key];

// If the value has a toJSON method, call it to obtain a replacement value.

    if (value && typeof value === 'object' &&
            typeof value.toJSON === 'function') {
        value = value.toJSON(key);
    }

// If we were called with a replacer function, then call the replacer to
// obtain a replacement value.

    if (typeof rep === 'function') {
        value = rep.call(holder, key, value);
    }

// What happens next depends on the value's type.

    switch (typeof value) {
    case 'string':
        return quote(value);

    case 'number':

// JSON numbers must be finite. Encode non-finite numbers as null.

        return isFinite(value) ? String(value) : 'null';

    case 'boolean':
    case 'null':

// If the value is a boolean or null, convert it to a string. Note:
// typeof null does not produce 'null'. The case is included here in
// the remote chance that this gets fixed someday.

        return String(value);

// If the type is 'object', we might be dealing with an object or an array or
// null.

    case 'object':

// Due to a specification blunder in ECMAScript, typeof null is 'object',
// so watch out for that case.

        if (!value) {
            return 'null';
        }

// Make an array to hold the partial results of stringifying this object value.

        gap += indent;
        partial = [];

// Is the value an array?

        if (Object.prototype.toString.apply(value) === '[object Array]') {

// The value is an array. Stringify every element. Use null as a placeholder
// for non-JSON values.

            length = value.length;
            for (i = 0; i < length; i += 1) {
                partial[i] = str(i, value) || 'null';
            }

// Join all of the elements together, separated with commas, and wrap them in
// brackets.

            v = partial.length === 0
                ? '[]'
                : gap
                ? '[\n' + gap + partial.join(',\n' + gap) + '\n' + mind + ']'
                : '[' + partial.join(',') + ']';
            gap = mind;
            return v;
        }

// If the replacer is an array, use it to select the members to be stringified.

        if (rep && typeof rep === 'object') {
            length = rep.length;
            for (i = 0; i < length; i += 1) {
                if (typeof rep[i] === 'string') {
                    k = rep[i];
                    v = str(k, value);
                    if (v) {
                        partial.push(quote(k) + (gap ? ': ' : ':') + v);
                    }
                }
            }
        } else {

// Otherwise, iterate through all of the keys in the object.
            var keysSorted = Object.keys(value).sort()
            for (i in keysSorted) {
                k = keysSorted[i]
                if (Object.prototype.hasOwnProperty.call(value, k)) {
                    v = str(k, value);
                    if (v) {
                        partial.push(quote(k) + (gap ? ': ' : ':') + v);
                    }
                }
            }
        }

// Join all of the member texts together, separated with commas,
// and wrap them in braces.

        v = partial.length === 0
            ? '{}'
            : gap
            ? '{\n' + gap + partial.join(',\n' + gap) + '\n' + mind + '}'
            : '{' + partial.join(',') + '}';
        gap = mind;
        return v;
    }
}

// If the JSON object does not yet have a stringify method, give it one.
var stringify = function (value, replacer, space) {

// The stringify method takes a value and an optional replacer, and an optional
// space parameter, and returns a JSON text. The replacer can be a function
// that can replace values, or an array of strings that will select the keys.
// A default replacer method can be provided. Use of the space parameter can
// produce text that is more easily readable.

    var i;
    gap = '';
    indent = '';

// If the space parameter is a number, make an indent string containing that
// many spaces.

    if (typeof space === 'number') {
        for (i = 0; i < space; i += 1) {
            indent += ' ';
        }

// If the space parameter is a string, it will be used as the indent string.

    } else if (typeof space === 'string') {
        indent = space;
    }

// If there is a replacer, it must be a function or an array.
// Otherwise, throw an error.

    rep = replacer;
    if (replacer && typeof replacer !== 'function' &&
            (typeof replacer !== 'object' ||
            typeof replacer.length !== 'number')) {
        throw new Error('JSON.stringify');
    }

// Make a fake root object containing our value under the key of ''.
// Return the result of stringifying the value.

    return str('', {'': value});
};

module.exports = stringify