import * as React from 'react';
import * as _ from 'lodash';
import {IntField, DecField, NumberField} from '../field';
import {CharsControl} from './charsControl';

const ErrInvalidNumber = '无效的数字';
const ErrMin = '最小值为';
const ErrMax = '最大值为';

const KeyCode_Neg = 45;
const KeyCode_Dot = 46;

export class NumberControl extends CharsControl {
    protected field: IntField | DecField | NumberField;
    protected value: number;
    protected extraChars: number[];
    
    protected init() {
        super.init();
        this.extraChars = [];
        let {min, max} = this.field;
        if (min !== undefined) {
            this.rules.push((v:number) => {if (v === undefined) return; if (v<min) return ErrMin + min; return true;});
            if (min < 0) this.extraChars.push(KeyCode_Neg);
        }
        else {
            this.extraChars.push(KeyCode_Neg);
        }

        if (max !== undefined) {
            this.rules.push((v:number) => {if (v === undefined) return; if (v>max) return ErrMax + max; return true});
        }
        switch (this.field.type) {
            case 'dec':
            case 'number': this.extraChars.push(KeyCode_Dot); break;
        }
    }

    protected parseValue(value?:string):any {
        if (value === undefined) return undefined;
        if (value.trim().length === 0) return undefined;
        let n = Number.parseFloat(value);
        if (isNaN(n)) throw new Error(ErrInvalidNumber);
        return n;
    }

    protected setProps() {
        super.setProps();
        _.assign(this.props, {
            type: 'number',
            step: (this.field as DecField).step,
            onKeyPress: this.onKeyPress.bind(this),
        });
    }

    onKeyPress(event:KeyboardEvent) {
        let ch = event.charCode;
        if (ch === 8 || ch === 0 || ch === 13 || ch >= 48 && ch <= 57) return;
        if (this.extraChars !== undefined) {
            if (this.extraChars.indexOf(ch) >= 0) {
                switch (ch) {
                    case KeyCode_Dot: this.onKeyDot(); break;
                    case KeyCode_Neg: this.onKeyNeg(); event.preventDefault(); break;
                }
                return;
            }
        }
        event.preventDefault();
    }

    private onKeyDot() {
        let v = this.element.value;
        let p = v.indexOf('.');
        if (p >= 0) this.element.value = v.replace('.', '');
    }
    private onKeyNeg() {
        let v = this.element.value;
        let p = v.indexOf('-');
        if (p >= 0) v = v.replace('-', '');
        else v = '-'+v;
        this.element.value = v;
    }
}