import { passwordChars } from '../shared';

function generate(length: number): string;
function generate(
    length: number,
    exclude: { number?: boolean; lower?: boolean; upper?: boolean; special?: boolean },
): string;
function generate(
    length: number,
    exclude?: { number?: boolean; lower?: boolean; upper?: boolean; special?: boolean },
): string {
    if (length <= 3) throw new Error('Length must be bigger than 3');
    if (exclude?.number && exclude?.lower && exclude?.upper && exclude?.special)
        throw new Error('All possible chars are excluded');

    const getRandomChar = (chars: string): string => chars[Math.floor(Math.random() * chars.length)];

    const password: string[] = [];
    if (!exclude?.number) password.push(getRandomChar(passwordChars.number));
    if (!exclude?.lower) password.push(getRandomChar(passwordChars.lower));
    if (!exclude?.upper) password.push(getRandomChar(passwordChars.upper));
    if (!exclude?.special) password.push(getRandomChar(passwordChars.special));

    const fullChars: string = [
        !exclude?.number ? passwordChars.number : '',
        !exclude?.lower ? passwordChars.lower : '',
        !exclude?.upper ? passwordChars.upper : '',
        !exclude?.special ? passwordChars.special : '',
    ].join('');
    while (password.length < length) password.push(getRandomChar(fullChars));

    return password.sort(() => (Math.random() < 0.5 ? 1 : -1)).join('');
}

function getStrength(password: string): number {
    const count = {
        upper: 0,
        lower: 0,
        number: 0,
        symbol: 0,
        middle: 0,
        repeatInc: 0,
        repeatChar: 0,
        consecutiveUpper: 0,
        consecutiveLower: 0,
        consecutiveNumber: 0,
        sequentialLetter: 0,
        sequentialNumber: 0,
        sequentialSymbol: 0,
    };

    const chars = { letter: passwordChars.lower, number: passwordChars.number, symbol: passwordChars.special };
    const aPassword = password.replace(/\s+/g, '').split(/\s*/);

    let lastCharType: null | 'U' | 'L' | 'N' | 'S' = null;
    aPassword.forEach((character: string, index: number) => {
        if (character.match(/[A-Z]/g)) {
            count.upper++;
            if (lastCharType === 'U') count.consecutiveUpper++;
            lastCharType = 'U';
        } else if (character.match(/[a-z]/g)) {
            count.lower++;
            if (lastCharType === 'L') count.consecutiveLower++;
            lastCharType = 'L';
        } else if (character.match(/[0-9]/g)) {
            count.number++;
            if (index > 0 && index < aPassword.length - 1) count.middle++;
            if (lastCharType === 'N') count.consecutiveNumber++;
            lastCharType = 'N';
        } else {
            count.symbol++;
            if (index > 0 && index < aPassword.length - 1) count.middle++;
            lastCharType = 'S';
        }

        let exists: boolean = false;
        aPassword.forEach((checkCharacter: string, checkIndex: number) => {
            if (character === checkCharacter && index !== checkIndex) {
                exists = true;
                count.repeatInc += Math.abs(aPassword.length / (checkIndex - index));
            }
        });
        if (exists) {
            count.repeatChar++;
            const unique: number = aPassword.length - count.repeatChar;
            count.repeatInc = unique !== 0 ? Math.ceil(count.repeatInc / unique) : Math.ceil(count.repeatInc);
        }
    });

    const requirement: number =
        (password.length >= 8 ? 1 : 0) +
        (count.upper !== 0 ? 1 : 0) +
        (count.lower !== 0 ? 1 : 0) +
        (count.number !== 0 ? 1 : 0) +
        (count.symbol !== 0 ? 1 : 0);

    for (let l = 0; l < chars.letter.length - 2; l++) {
        const fwd: string = chars.letter.substring(l, l + 3);
        const rev: string = fwd.split('').reverse().join('');

        if (password.toLowerCase().indexOf(fwd) !== -1 || password.toLowerCase().indexOf(rev) !== -1)
            count.sequentialLetter++;
    }

    for (let n = 0; n < chars.number.length - 2; n++) {
        const fwd: string = chars.number.substring(n, n + 3);
        const rev: string = fwd.split('').reverse().join('');

        if (password.toLowerCase().indexOf(fwd) !== -1 || password.toLowerCase().indexOf(rev) !== -1)
            count.sequentialNumber++;
    }

    for (let s = 0; s < chars.symbol.length - 2; s++) {
        const fwd: string = chars.symbol.substring(s, s + 3);
        const rev: string = fwd.split('').reverse().join('');

        if (password.toLowerCase().indexOf(fwd) !== -1 || password.toLowerCase().indexOf(rev) !== -1)
            count.sequentialSymbol++;
    }

    const additions: number = [
        // Number of Characters
        password.length * 4,
        // Uppercase Letters
        count.upper ? (password.length - count.upper) * 2 : 0,
        // Lowercase Letters
        count.lower ? (password.length - count.lower) * 2 : 0,
        // Numbers
        count.number * 4,
        // Symbols
        count.symbol * 6,
        // 	Middle Numbers or Symbols
        count.middle * 2,
        // Requirements
        requirement > 3 ? requirement * 2 : 0,
    ].reduce((pv, cv) => pv + cv, 0);

    const deductions: number = [
        // Letters Only
        count.number !== 0 || count.symbol !== 0 ? 0 : password.length,
        // Numbers Only
        count.upper !== 0 || count.lower !== 0 || count.symbol !== 0 ? 0 : password.length,
        // Repeat Characters (Case Insensitive)
        count.repeatInc,
        // Consecutive Uppercase Letters
        count.consecutiveUpper * 2,
        // Consecutive Lowercase Letters
        count.consecutiveLower * 2,
        // Consecutive Numbers
        count.consecutiveNumber * 2,
        // Sequential Letters (3+)
        count.sequentialLetter * 3,
        // Sequential Numbers (3+)
        count.sequentialNumber * 3,
        // Sequential Symbols (3+)
        count.sequentialSymbol * 3,
    ].reduce((pv, cv) => pv + cv, 0);

    const score: number = (additions - deductions) / 10;
    return score > 10 ? 10 : score < 0 ? 0 : score;
}

export const PASSWORD = {
    generate,
    getStrength,
};