'use strict';

// Load modules

const Net = require('net');
const Hoek = require('hoek');
let Isemail;                            // Loaded on demand
const Any = require('../any');
const Ref = require('../../ref');
const JoiDate = require('../date');
const Uri = require('./uri');
const Ip = require('./ip');

// Declare internals

const internals = {
    uriRegex: Uri.createUriRegex(),
    ipRegex: Ip.createIpRegex(['ipv4', 'ipv6', 'ipvfuture'], 'optional'),
    guidBrackets: {
        '{': '}', '[': ']', '(': ')', '': ''
    },
    guidVersions: {
        uuidv1: '1',
        uuidv2: '2',
        uuidv3: '3',
        uuidv4: '4',
        uuidv5: '5'
    },
    cidrPresences: ['required', 'optional', 'forbidden'],
    normalizationForms: ['NFC', 'NFD', 'NFKC', 'NFKD']
};

internals.String = class extends Any {

    constructor() {

        super();
        this._type = 'string';
        this._invalids.add('');
    }

    _base(value, state, options) {

        if (typeof value === 'string' &&
            options.convert) {

            if (this._flags.normalize) {
                value = value.normalize(this._flags.normalize);
            }

            if (this._flags.case) {
                value = (this._flags.case === 'upper' ? value.toLocaleUpperCase() : value.toLocaleLowerCase());
            }

            if (this._flags.trim) {
                value = value.trim();
            }

            if (this._inner.replacements) {

                for (let i = 0; i < this._inner.replacements.length; ++i) {
                    const replacement = this._inner.replacements[i];
                    value = value.replace(replacement.pattern, replacement.replacement);
                }
            }

            if (this._flags.truncate) {
                for (let i = 0; i < this._tests.length; ++i) {
                    const test = this._tests[i];
                    if (test.name === 'max') {
                        value = value.slice(0, test.arg);
                        break;
                    }
                }
            }

            if (this._flags.byteAligned && value.length % 2 !== 0) {
                value = `0${value}`;
            }
        }

        return {
            value,
            errors: (typeof value === 'string') ? null : this.createError('string.base', { value }, state, options)
        };
    }

    insensitive() {

        if (this._flags.insensitive) {
            return this;
        }

        const obj = this.clone();
        obj._flags.insensitive = true;
        return obj;
    }

    creditCard() {

        return this._test('creditCard', undefined, function (value, state, options) {

            let i = value.length;
            let sum = 0;
            let mul = 1;

            while (i--) {
                const char = value.charAt(i) * mul;
                sum = sum + (char - (char > 9) * 9);
                mul = mul ^ 3;
            }

            const check = (sum % 10 === 0) && (sum > 0);
            return check ? value : this.createError('string.creditCard', { value }, state, options);
        });
    }

    regex(pattern, patternOptions) {

        Hoek.assert(pattern instanceof RegExp, 'pattern must be a RegExp');

        const patternObject = {
            pattern: new RegExp(pattern.source, pattern.ignoreCase ? 'i' : undefined)         // Future version should break this and forbid unsupported regex flags
        };

        if (typeof patternOptions === 'string') {
            patternObject.name = patternOptions;
        }
        else if (typeof patternOptions === 'object') {
            patternObject.invert = !!patternOptions.invert;

            if (patternOptions.name) {
                patternObject.name = patternOptions.name;
            }
        }

        const errorCode = ['string.regex', patternObject.invert ? '.invert' : '', patternObject.name ? '.name' : '.base'].join('');

        return this._test('regex', patternObject, function (value, state, options) {

            const patternMatch = patternObject.pattern.test(value);

            if (patternMatch ^ patternObject.invert) {
                return value;
            }

            return this.createError(errorCode, { name: patternObject.name, pattern: patternObject.pattern, value }, state, options);
        });
    }

    alphanum() {

        return this._test('alphanum', undefined, function (value, state, options) {

            if (/^[a-zA-Z0-9]+$/.test(value)) {
                return value;
            }

            return this.createError('string.alphanum', { value }, state, options);
        });
    }

    token() {

        return this._test('token', undefined, function (value, state, options) {

            if (/^\w+$/.test(value)) {
                return value;
            }

            return this.createError('string.token', { value }, state, options);
        });
    }

    email(isEmailOptions) {

        if (isEmailOptions) {
            Hoek.assert(typeof isEmailOptions === 'object', 'email options must be an object');
            Hoek.assert(typeof isEmailOptions.checkDNS === 'undefined', 'checkDNS option is not supported');
            Hoek.assert(typeof isEmailOptions.tldWhitelist === 'undefined' ||
                typeof isEmailOptions.tldWhitelist === 'object', 'tldWhitelist must be an array or object');
            Hoek.assert(
                typeof isEmailOptions.minDomainAtoms === 'undefined' ||
                Number.isSafeInteger(isEmailOptions.minDomainAtoms) &&
                isEmailOptions.minDomainAtoms > 0,
                'minDomainAtoms must be a positive integer'
            );
            Hoek.assert(
                typeof isEmailOptions.errorLevel === 'undefined' ||
                typeof isEmailOptions.errorLevel === 'boolean' ||
                (
                    Number.isSafeInteger(isEmailOptions.errorLevel) &&
                    isEmailOptions.errorLevel >= 0
                ),
                'errorLevel must be a non-negative integer or boolean'
            );
        }

        return this._test('email', isEmailOptions, function (value, state, options) {

            Isemail = Isemail || require('isemail');

            try {
                const result = Isemail.validate(value, isEmailOptions);
                if (result === true || result === 0) {
                    return value;
                }
            }
            catch (e) { }

            return this.createError('string.email', { value }, state, options);
        });
    }

    ip(ipOptions = {}) {

        let regex = internals.ipRegex;
        Hoek.assert(typeof ipOptions === 'object', 'options must be an object');

        if (ipOptions.cidr) {
            Hoek.assert(typeof ipOptions.cidr === 'string', 'cidr must be a string');
            ipOptions.cidr = ipOptions.cidr.toLowerCase();

            Hoek.assert(Hoek.contain(internals.cidrPresences, ipOptions.cidr), 'cidr must be one of ' + internals.cidrPresences.join(', '));

            // If we only received a `cidr` setting, create a regex for it. But we don't need to create one if `cidr` is "optional" since that is the default
            if (!ipOptions.version && ipOptions.cidr !== 'optional') {
                regex = Ip.createIpRegex(['ipv4', 'ipv6', 'ipvfuture'], ipOptions.cidr);
            }
        }
        else {

            // Set our default cidr strategy
            ipOptions.cidr = 'optional';
        }

        let versions;
        if (ipOptions.version) {
            if (!Array.isArray(ipOptions.version)) {
                ipOptions.version = [ipOptions.version];
            }

            Hoek.assert(ipOptions.version.length >= 1, 'version must have at least 1 version specified');

            versions = [];
            for (let i = 0; i < ipOptions.version.length; ++i) {
                let version = ipOptions.version[i];
                Hoek.assert(typeof version === 'string', 'version at position ' + i + ' must be a string');
                version = version.toLowerCase();
                Hoek.assert(Ip.versions[version], 'version at position ' + i + ' must be one of ' + Object.keys(Ip.versions).join(', '));
                versions.push(version);
            }

            // Make sure we have a set of versions
            versions = Hoek.unique(versions);

            regex = Ip.createIpRegex(versions, ipOptions.cidr);
        }

        return this._test('ip', ipOptions, function (value, state, options) {

            if (regex.test(value)) {
                return value;
            }

            if (versions) {
                return this.createError('string.ipVersion', { value, cidr: ipOptions.cidr, version: versions }, state, options);
            }

            return this.createError('string.ip', { value, cidr: ipOptions.cidr }, state, options);
        });
    }

    uri(uriOptions) {

        let customScheme = '';
        let allowRelative = false;
        let relativeOnly = false;
        let allowQuerySquareBrackets = false;
        let regex = internals.uriRegex;

        if (uriOptions) {
            Hoek.assert(typeof uriOptions === 'object', 'options must be an object');

            const unknownOptions = Object.keys(uriOptions).filter((key) => !['scheme', 'allowRelative', 'relativeOnly', 'allowQuerySquareBrackets'].includes(key));
            Hoek.assert(unknownOptions.length === 0, `options contain unknown keys: ${unknownOptions}`);

            if (uriOptions.scheme) {
                Hoek.assert(uriOptions.scheme instanceof RegExp || typeof uriOptions.scheme === 'string' || Array.isArray(uriOptions.scheme), 'scheme must be a RegExp, String, or Array');

                if (!Array.isArray(uriOptions.scheme)) {
                    uriOptions.scheme = [uriOptions.scheme];
                }

                Hoek.assert(uriOptions.scheme.length >= 1, 'scheme must have at least 1 scheme specified');

                // Flatten the array into a string to be used to match the schemes.
                for (let i = 0; i < uriOptions.scheme.length; ++i) {
                    const scheme = uriOptions.scheme[i];
                    Hoek.assert(scheme instanceof RegExp || typeof scheme === 'string', 'scheme at position ' + i + ' must be a RegExp or String');

                    // Add OR separators if a value already exists
                    customScheme = customScheme + (customScheme ? '|' : '');

                    // If someone wants to match HTTP or HTTPS for example then we need to support both RegExp and String so we don't escape their pattern unknowingly.
                    if (scheme instanceof RegExp) {
                        customScheme = customScheme + scheme.source;
                    }
                    else {
                        Hoek.assert(/[a-zA-Z][a-zA-Z0-9+-\.]*/.test(scheme), 'scheme at position ' + i + ' must be a valid scheme');
                        customScheme = customScheme + Hoek.escapeRegex(scheme);
                    }
                }
            }

            if (uriOptions.allowRelative) {
                allowRelative = true;
            }

            if (uriOptions.relativeOnly) {
                relativeOnly = true;
            }

            if (uriOptions.allowQuerySquareBrackets) {
                allowQuerySquareBrackets = true;
            }
        }

        if (customScheme || allowRelative || relativeOnly || allowQuerySquareBrackets) {
            regex = Uri.createUriRegex(customScheme, allowRelative, relativeOnly, allowQuerySquareBrackets);
        }

        return this._test('uri', uriOptions, function (value, state, options) {

            if (regex.test(value)) {
                return value;
            }

            if (relativeOnly) {
                return this.createError('string.uriRelativeOnly', { value }, state, options);
            }

            if (customScheme) {
                return this.createError('string.uriCustomScheme', { scheme: customScheme, value }, state, options);
            }

            return this.createError('string.uri', { value }, state, options);
        });
    }

    isoDate() {

        return this._test('isoDate', undefined, function (value, state, options) {

            if (JoiDate._isIsoDate(value)) {
                if (!options.convert) {
                    return value;
                }

                const d = new Date(value);
                if (!isNaN(d.getTime())) {
                    return d.toISOString();
                }
            }

            return this.createError('string.isoDate', { value }, state, options);
        });
    }

    guid(guidOptions) {

        let versionNumbers = '';

        if (guidOptions && guidOptions.version) {
            if (!Array.isArray(guidOptions.version)) {
                guidOptions.version = [guidOptions.version];
            }

            Hoek.assert(guidOptions.version.length >= 1, 'version must have at least 1 valid version specified');
            const versions = new Set();

            for (let i = 0; i < guidOptions.version.length; ++i) {
                let version = guidOptions.version[i];
                Hoek.assert(typeof version === 'string', 'version at position ' + i + ' must be a string');
                version = version.toLowerCase();
                const versionNumber = internals.guidVersions[version];
                Hoek.assert(versionNumber, 'version at position ' + i + ' must be one of ' + Object.keys(internals.guidVersions).join(', '));
                Hoek.assert(!(versions.has(versionNumber)), 'version at position ' + i + ' must not be a duplicate.');

                versionNumbers += versionNumber;
                versions.add(versionNumber);
            }
        }

        const guidRegex = new RegExp(`^([\\[{\\(]?)[0-9A-F]{8}([:-]?)[0-9A-F]{4}\\2?[${versionNumbers || '0-9A-F'}][0-9A-F]{3}\\2?[${versionNumbers ? '89AB' : '0-9A-F'}][0-9A-F]{3}\\2?[0-9A-F]{12}([\\]}\\)]?)$`, 'i');

        return this._test('guid', guidOptions, function (value, state, options) {

            const results = guidRegex.exec(value);

            if (!results) {
                return this.createError('string.guid', { value }, state, options);
            }

            // Matching braces
            if (internals.guidBrackets[results[1]] !== results[results.length - 1]) {
                return this.createError('string.guid', { value }, state, options);
            }

            return value;
        });
    }

    hex(hexOptions = {}) {

        Hoek.assert(typeof hexOptions === 'object', 'hex options must be an object');
        Hoek.assert(typeof hexOptions.byteAligned === 'undefined' || typeof hexOptions.byteAligned === 'boolean',
            'byteAligned must be boolean');

        const byteAligned = hexOptions.byteAligned === true;
        const regex = /^[a-f0-9]+$/i;

        const obj = this._test('hex', regex, function (value, state, options) {

            if (regex.test(value)) {
                if (byteAligned && value.length % 2 !== 0) {
                    return this.createError('string.hexAlign', { value }, state, options);
                }
                return value;
            }

            return this.createError('string.hex', { value }, state, options);
        });

        if (byteAligned) {
            obj._flags.byteAligned = true;
        }

        return obj;
    }

    base64(base64Options = {}) {

        // Validation.
        Hoek.assert(typeof base64Options === 'object', 'base64 options must be an object');
        Hoek.assert(typeof base64Options.paddingRequired === 'undefined' || typeof base64Options.paddingRequired === 'boolean',
            'paddingRequired must be boolean');

        // Determine if padding is required.
        const paddingRequired = base64Options.paddingRequired === false ?
            base64Options.paddingRequired
            : base64Options.paddingRequired || true;

        // Set validation based on preference.
        const regex = paddingRequired ?
            // Padding is required.
            /^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/
            // Padding is optional.
            : /^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}(==)?|[A-Za-z0-9+\/]{3}=?)?$/;

        return this._test('base64', regex, function (value, state, options) {

            if (regex.test(value)) {
                return value;
            }

            return this.createError('string.base64', { value }, state, options);
        });
    }

    dataUri(dataUriOptions = {}) {

        const regex = /^data:[\w\/\+]+;((charset=[\w-]+|base64),)?(.*)$/;

        // Determine if padding is required.
        const paddingRequired = dataUriOptions.paddingRequired === false ?
            dataUriOptions.paddingRequired
            : dataUriOptions.paddingRequired || true;

        const base64regex =  paddingRequired ?
            /^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/
            : /^(?:[A-Za-z0-9+\/]{4})*(?:[A-Za-z0-9+\/]{2}(==)?|[A-Za-z0-9+\/]{3}=?)?$/;

        return this._test('dataUri', regex, function (value, state, options) {

            const matches = value.match(regex);

            if (matches) {
                if (!matches[2]) {
                    return value;
                }

                if (matches[2] !== 'base64') {
                    return value;
                }

                if (base64regex.test(matches[3])) {
                    return value;
                }
            }

            return this.createError('string.dataUri', { value }, state, options);
        });
    }

    hostname() {

        const regex = /^(([a-zA-Z0-9]|[a-zA-Z0-9][a-zA-Z0-9\-]*[a-zA-Z0-9])\.)*([A-Za-z0-9]|[A-Za-z0-9][A-Za-z0-9\-]*[A-Za-z0-9])$/;

        return this._test('hostname', undefined, function (value, state, options) {

            if ((value.length <= 255 && regex.test(value)) ||
                Net.isIPv6(value)) {

                return value;
            }

            return this.createError('string.hostname', { value }, state, options);
        });
    }

    normalize(form = 'NFC') {

        Hoek.assert(Hoek.contain(internals.normalizationForms, form), 'normalization form must be one of ' + internals.normalizationForms.join(', '));

        const obj = this._test('normalize', form, function (value, state, options) {

            if (options.convert ||
                value === value.normalize(form)) {

                return value;
            }

            return this.createError('string.normalize', { value, form }, state, options);
        });

        obj._flags.normalize = form;
        return obj;
    }

    lowercase() {

        const obj = this._test('lowercase', undefined, function (value, state, options) {

            if (options.convert ||
                value === value.toLocaleLowerCase()) {

                return value;
            }

            return this.createError('string.lowercase', { value }, state, options);
        });

        obj._flags.case = 'lower';
        return obj;
    }

    uppercase() {

        const obj = this._test('uppercase', undefined, function (value, state, options) {

            if (options.convert ||
                value === value.toLocaleUpperCase()) {

                return value;
            }

            return this.createError('string.uppercase', { value }, state, options);
        });

        obj._flags.case = 'upper';
        return obj;
    }

    trim(enabled = true) {

        Hoek.assert(typeof enabled === 'boolean', 'option must be a boolean');

        if ((this._flags.trim && enabled) || (!this._flags.trim && !enabled)) {
            return this;
        }

        let obj;
        if (enabled) {
            obj = this._test('trim', undefined, function (value, state, options) {

                if (options.convert ||
                    value === value.trim()) {

                    return value;
                }

                return this.createError('string.trim', { value }, state, options);
            });
        }
        else {
            obj = this.clone();
            obj._tests = obj._tests.filter((test) => test.name !== 'trim');
        }

        obj._flags.trim = enabled;
        return obj;
    }

    replace(pattern, replacement) {

        if (typeof pattern === 'string') {
            pattern = new RegExp(Hoek.escapeRegex(pattern), 'g');
        }

        Hoek.assert(pattern instanceof RegExp, 'pattern must be a RegExp');
        Hoek.assert(typeof replacement === 'string', 'replacement must be a String');

        // This can not be considere a test like trim, we can't "reject"
        // anything from this rule, so just clone the current object
        const obj = this.clone();

        if (!obj._inner.replacements) {
            obj._inner.replacements = [];
        }

        obj._inner.replacements.push({
            pattern,
            replacement
        });

        return obj;
    }

    truncate(enabled) {

        const value = enabled === undefined ? true : !!enabled;

        if (this._flags.truncate === value) {
            return this;
        }

        const obj = this.clone();
        obj._flags.truncate = value;
        return obj;
    }

};

internals.compare = function (type, compare) {

    return function (limit, encoding) {

        const isRef = Ref.isRef(limit);

        Hoek.assert((Number.isSafeInteger(limit) && limit >= 0) || isRef, 'limit must be a positive integer or reference');
        Hoek.assert(!encoding || Buffer.isEncoding(encoding), 'Invalid encoding:', encoding);

        return this._test(type, limit, function (value, state, options) {

            let compareTo;
            if (isRef) {
                compareTo = limit(state.reference || state.parent, options);

                if (!Number.isSafeInteger(compareTo)) {
                    return this.createError('string.ref', { ref: limit.key }, state, options);
                }
            }
            else {
                compareTo = limit;
            }

            if (compare(value, compareTo, encoding)) {
                return value;
            }

            return this.createError('string.' + type, { limit: compareTo, value, encoding }, state, options);
        });
    };
};


internals.String.prototype.min = internals.compare('min', (value, limit, encoding) => {

    const length = encoding ? Buffer.byteLength(value, encoding) : value.length;
    return length >= limit;
});


internals.String.prototype.max = internals.compare('max', (value, limit, encoding) => {

    const length = encoding ? Buffer.byteLength(value, encoding) : value.length;
    return length <= limit;
});


internals.String.prototype.length = internals.compare('length', (value, limit, encoding) => {

    const length = encoding ? Buffer.byteLength(value, encoding) : value.length;
    return length === limit;
});

// Aliases

internals.String.prototype.uuid = internals.String.prototype.guid;

module.exports = new internals.String();