/**
 * Generate and maintain a form based on a given layout (in object structure) and a data model
 */
import React from 'react';
import validateForm from './impl/form-validate';
import { setValue } from '../commons/utils';
import formRender from './impl/form-render';
import createSnapshot from './impl/form-snapshot';
import formControl from './controls/form-control';
import { initDefaultValues } from './impl/form-init';
import FormUtils from './form-utils';

import './form.less';

/**
 * Create a form based on a given json layout and a data model
 */
export default class Form extends React.Component {

    /**
     * Register a new type to be supported by the forms
     * @param  {[type]} Comp [description]
     */
    static registerType(Comp) {
        if (Comp.constructor.name === 'Array') {
            Comp.forEach(item => Form.registerType(item));
            return;
        }

        const name = Comp.typeName();

        if (__DEV__) {
            if (!name) {
                /* eslint no-console: "off" */
                console.log('No name defined for ' + (Comp.typeName ? Comp.typeName() : Comp) + '.typeName()');
            }
        }

        if (name.constructor.name === 'Array') {
            name.forEach(k => {
                Form.types[k] = formControl(Comp);
            });
        }

        Form.types[name] = formControl(Comp);
    }

    constructor(props) {
        super(props);
        this._onChange = this._onChange.bind(this);
        this._onRequest = this._onRequest.bind(this);
        this.state = {};

        // this code block is just available in development mode
        if (__DEV__) {
            if (!this.props.doc) {
                throw new Error('Form document is required (property doc)');
            }

            const schema = this.props.schema;
            if (!schema) {
                throw new Error('Form schema is required (property schema)');
            }

            // validate the schema
            if (schema.controls) {
                schema.controls.forEach(elem => {
                    if (!elem.type) {
                        throw new Error('Element type not defined for ' + elem.property);
                    }

                    const comp = FormUtils.getControl(elem);
                    if (!comp) {
                        throw new Error('Component type not found: ' + elem.type);
                    }
                });
            }
        }
    }

    componentWillMount() {
        initDefaultValues(this);

        this.updateSnapshot();

        // start recording any request made by the children
        this.recordRequests();
    }

    componentDidMount() {
        const self = this;
        // called first time the form is mounted
        this.applyRequests().then(res => {
            // once the form is ready, set the focus
            self.focus();
            return res;
        });
    }

    componentWillUpdate() {
        this.recordRequests();
    }

    componentDidUpdate() {
        // called on every consecutive render (except the first render)
        this.applyRequests();
    }

    /**
     * Validate the form and return validation messages, if any erro is found
     * @return {[type]}           [description]
     */
    validate() {
        return validateForm(this);
    }

    /**
     * Set the focus on the first available control
     * @return {[type]} [description]
     */
    focus() {
        // set focus on the first control that supports it
        this.state.snapshots.find(it => it.snapshot.readOnly ? false : this.refs[it.snapshot.id].focus());
    }

    /**
     * Update element state list. Element state is just update if it has changed
     * @return {Array} List of element states
     */
    updateSnapshot() {
        const lst = createSnapshot(this);
        this.setState({ snapshots: lst });
        return lst;
    }

    /**
     * Called every time a component value is changed
     */
    _onChange(evt) {
        // update value in the data model
        const schema = evt.schema;
        const value = evt.value;
        setValue(this.props.doc, schema.property, value, true);

        // check if schema is mapping changes
        if (schema.onChange) {
            schema.onChange.call(this.props.doc, this.props.doc);
        }

        // notify parent about changes
        if (this.props.onChange) {
            this.props.onChange(this.props.doc, schema, value);
        }

        this.updateSnapshot();
    }

    /**
     * Receive a request from a control to be dispatched to the server
     * @param  {[type]} schema [description]
     * @param  {[type]} req    [description]
     * @return {[type]}        [description]
     */
    _onRequest(schema, req) {
        if (this.reqs) {
            this.reqs.push({ schema: schema, req: req });
        } else {
            this.recordRequests();
            this.reqs.push({ schema: schema, req: req });
            this.applyRequests();
        }
    }

    recordRequests() {
        this.reqs = [];
    }

    /**
     * Apply the requests made by the controls during the render phase. If there are
     * requests made by the client using the onRequest event, these requests are
     * gathered together and sent once to the server
     */
    applyRequests() {
        // check if there is any request to be dispatched
        if (!this.reqs || this.reqs.length === 0) {
            if (!this.state.resources && !this.props.resources) {
                this.setState({ resources: [] });
            }
            return Promise.resolve([]);
        }

        // mount request list
        const req = this.reqs.map(it => ({
            id: it.schema.id, cmd: it.req.cmd, params: it.req.params
        }));

        const self = this;

        // request the server all the requests that came from the children
        const prom = FormUtils.serverRequest(req).then(res => self.setState({ resources: Object.assign({}, this.state.resources, res) }));

        // clean up the requests
        delete this.reqs;

        // return the promise to fullfill the request
        return prom;
    }

    /**
     * Rend form
     * @return {[type]} [description]
     */
    render() {
        // render the form
        const form = formRender(this);
        return React.createElement(
            'div',
            { className: this.props.className },
            form
        );
    }
}

Form.propTypes = {
    schema: React.PropTypes.object,
    doc: React.PropTypes.object,
    errors: React.PropTypes.array,
    resources: React.PropTypes.object,
    onChange: React.PropTypes.func,
    readOnly: React.PropTypes.bool,
    className: React.PropTypes.string
};

/**
 * List of supported types
 * @type {Object}
 */
Form.types = {};

Form.control = formControl;

/**
 * Automatically register common controls
 */

import InputControl from './controls/input-control';
import BoolControl from './controls/bool-control';
import TextControl from './controls/text-control';
import SelectControl from './controls/select-control';
import DateControl from './controls/date-control';
import SubtitleControl from './controls/subtitle-control';
import GroupControl from './controls/group-control';
import PeriodControl from './controls/period-control';
import MonthYearControl from './controls/month-year-control';

Form.registerType([InputControl, BoolControl, TextControl, SelectControl, DateControl, SubtitleControl, GroupControl, PeriodControl, MonthYearControl]);