import {IPropertyListDescriptor, PropertyDescriptorParsingType} from '../IPropertyDescriptor';
import {CSSValue, isNumberToken, nonWhiteSpace} from '../syntax/parser';
import {TokenType} from '../syntax/tokenizer';
import {Context} from '../../core/context';

export interface COUNTER_INCREMENT {
    counter: string;
    increment: number;
}

export type CounterIncrement = COUNTER_INCREMENT[] | null;

export const counterIncrement: IPropertyListDescriptor<CounterIncrement> = {
    name: 'counter-increment',
    initialValue: 'none',
    prefix: true,
    type: PropertyDescriptorParsingType.LIST,
    parse: (_context: Context, tokens: CSSValue[]) => {
        if (tokens.length === 0) {
            return null;
        }

        const first = tokens[0];

        if (first.type === TokenType.IDENT_TOKEN && first.value === 'none') {
            return null;
        }

        const increments = [];
        const filtered = tokens.filter(nonWhiteSpace);

        for (let i = 0; i < filtered.length; i++) {
            const counter = filtered[i];
            const next = filtered[i + 1];
            if (counter.type === TokenType.IDENT_TOKEN) {
                const increment = next && isNumberToken(next) ? next.number : 1;
                increments.push({counter: counter.value, increment});
            }
        }

        return increments;
    }
};