import React from 'react';
import ReactDOM from 'react-dom';
import ClassNames from 'classnames';
import Input from '../input';
import events from '../utils/events';
import style from './style';

const POSITION = {
  AUTO: 'auto',
  DOWN: 'down',
  UP: 'up'
};

class Autocomplete extends React.Component {
  static propTypes = {
    className: React.PropTypes.string,
    direction: React.PropTypes.oneOf(['auto', 'up', 'down']),
    disabled: React.PropTypes.bool,
    error: React.PropTypes.string,
    label: React.PropTypes.string,
    multiple: React.PropTypes.bool,
    onChange: React.PropTypes.func,
    source: React.PropTypes.any,
    value: React.PropTypes.any
  };

  static defaultProps = {
    className: '',
    direction: 'auto',
    multiple: true,
    source: {}
  };

  state = {
    direction: this.props.direction,
    focus: false,
    query: this.query(this.props.value)
  };

  shouldComponentUpdate (nextProps, nextState) {
    if (!this.state.focus && nextState.focus && this.props.direction === POSITION.AUTO) {
      const direction = this.calculateDirection();
      if (this.state.direction !== direction) {
        this.setState({ direction });
        return false;
      }
    }
    return true;
  }

  handleChange = (keys, event) => {
    const key = this.props.multiple ? keys : keys[0];
    const query = this.query(key);
    if (this.props.onChange) this.props.onChange(key, event);
    this.setState({ focus: false, query }, () => { this.refs.input.blur(); });
  };

  handleQueryBlur = () => {
    if (this.state.focus) this.setState({focus: false});
  };

  handleQueryChange = (value) => {
    this.setState({query: value});
  };

  handleQueryFocus = () => {
    this.refs.suggestions.scrollTop = 0;
    this.setState({active: '', focus: true});
  };

  handleQueryKeyUp = (event) => {
    if (event.which === 13 && this.state.active) this.select(this.state.active, event);
    if (event.which === 27) this.refs.input.blur();
    if ([40, 38].indexOf(event.which) !== -1) {
      const suggestionsKeys = [...this.suggestions().keys()];
      let index = suggestionsKeys.indexOf(this.state.active) + (event.which === 40 ? +1 : -1);
      if (index < 0) index = suggestionsKeys.length - 1;
      if (index >= suggestionsKeys.length) index = 0;
      this.setState({active: suggestionsKeys[index]});
    }
  };

  handleSuggestionHover = (key) => {
    this.setState({active: key});
  };

  calculateDirection () {
    if (this.props.direction === 'auto') {
      const client = ReactDOM.findDOMNode(this.refs.input).getBoundingClientRect();
      const screen_height = window.innerHeight || document.documentElement.offsetHeight;
      const up = client.top > ((screen_height / 2) + client.height);
      return up ? 'up' : 'down';
    } else {
      return this.props.direction;
    }
  }

  query (key) {
    return !this.props.multiple && this.props.value ? this.source().get(key) : '';
  }

  suggestions () {
    const suggestions = new Map();
    const query = this.state.query.toLowerCase().trim() || '';
    const values = this.values();
    for (const [key, value] of this.source()) {
      if (!values.has(key) && value.toLowerCase().trim().startsWith(query)) {
        suggestions.set(key, value);
      }
    }
    return suggestions;
  }

  source () {
    const { source } = this.props;
    if (source.hasOwnProperty('length')) {
      return new Map(source.map((item) => [item, item]));
    } else {
      return new Map(Object.keys(source).map((key) => [key, source[key]]));
    }
  }

  values () {
    const valueMap = new Map();
    const values = this.props.multiple ? this.props.value : [this.props.value];
    for (const [k, v] of this.source()) {
      if (values.indexOf(k) !== -1) valueMap.set(k, v);
    }
    return valueMap;
  }

  select (key, event) {
    events.pauseEvent(event);
    const values = this.values(this.props.value);
    this.handleChange([key, ...values.keys()], event);
  }

  unselect (key, event) {
    const values = this.values(this.props.value);
    values.delete(key);
    this.handleChange([...values.keys()], event);
  }

  renderSelected () {
    if (this.props.multiple) {
      const selectedItems = [...this.values()].map(([key, value]) => {
        return <li key={key} className={style.value} onClick={this.unselect.bind(this, key)}>{value}</li>;
      });

      return <ul className={style.values}>{selectedItems}</ul>;
    }
  }

  renderSuggestions () {
    const suggestions = [...this.suggestions()].map(([key, value]) => {
      const className = ClassNames(style.suggestion, {[style.active]: this.state.active === key});
      return (
        <li
          key={key}
          className={className}
          onMouseDown={this.select.bind(this, key)}
          onMouseOver={this.handleSuggestionHover.bind(this, key)}
        >
          {value}
        </li>
      );
    });

    const className = ClassNames(style.suggestions, {[style.up]: this.state.direction === 'up'});
    return <ul ref='suggestions' className={className}>{suggestions}</ul>;
  }

  render () {
    const className = ClassNames(style.root, {
      [style.focus]: this.state.focus,
      [style.errored]: this.props.error
    }, this.props.className);

    return (
      <div data-react-toolbox='autocomplete' className={className}>
        {this.props.label ? <label className={style.label}>{this.props.label}</label> : null}
        {this.renderSelected()}
        <Input
          ref='input'
          {...this.props}
          className={style.input}
          label=''
          onBlur={this.handleQueryBlur}
          onChange={this.handleQueryChange}
          onFocus={this.handleQueryFocus}
          onKeyUp={this.handleQueryKeyUp}
          value={this.state.query}
        />
        {this.renderSuggestions()}
      </div>
    );
  }
}

export default Autocomplete;