'use strict';

const color = require('kleur');

const _require = require('sisteransi'),
      cursor = _require.cursor;

const Prompt = require('./prompt');

const _require2 = require('../util'),
      clear = _require2.clear,
      figures = _require2.figures,
      style = _require2.style,
      wrap = _require2.wrap,
      strip = _require2.strip;
/**
 * MultiselectPrompt Base Element
 * @param {Object} opts Options
 * @param {String} opts.message Message
 * @param {Array} opts.choices Array of choice objects
 * @param {String} [opts.hint] Hint to display
 * @param {String} [opts.warn] Hint shown for disabled choices
 * @param {Number} [opts.max] Max choices
 * @param {Number} [opts.cursor=0] Cursor start position
 * @param {Stream} [opts.stdin] The Readable stream to listen to
 * @param {Stream} [opts.stdout] The Writable stream to write readline data to
 */


class MultiselectPrompt extends Prompt {
  constructor(opts = {}) {
    super(opts);
    this.msg = opts.message;
    this.cursor = opts.cursor || 0;
    this.scrollIndex = opts.cursor || 0;
    this.hint = opts.hint || '';
    this.warn = opts.warn || '- This option is disabled -';
    this.minSelected = opts.min;
    this.showMinError = false;
    this.maxChoices = opts.max;
    this.instructions = opts.instructions;
    this.value = opts.choices.map((ch, idx) => {
      if (typeof ch === 'string') ch = {
        title: ch,
        value: idx
      };
      return {
        title: ch && (ch.title || ch.value || ch),
        description: ch && ch.description,
        value: ch && (ch.value || idx),
        selected: ch && ch.selected,
        disabled: ch && ch.disabled
      };
    });
    this.clear = clear('');

    if (!opts.overrideRender) {
      this.render();
    }
  }

  reset() {
    this.value.map(v => !v.selected);
    this.cursor = 0;
    this.fire();
    this.render();
  }

  selected() {
    return this.value.filter(v => v.selected);
  }

  abort() {
    this.done = this.aborted = true;
    this.fire();
    this.render();
    this.out.write('\n');
    this.close();
  }

  submit() {
    const selected = this.value.filter(e => e.selected);

    if (this.minSelected && selected.length < this.minSelected) {
      this.showMinError = true;
      this.render();
    } else {
      this.done = true;
      this.aborted = false;
      this.fire();
      this.render();
      this.out.write('\n');
      this.close();
    }
  }

  first() {
    this.cursor = 0;
    this.render();
  }

  last() {
    this.cursor = this.value.length - 1;
    this.render();
  }

  next() {
    this.cursor = (this.cursor + 1) % this.value.length;
    this.render();
  }

  up() {
    if (this.cursor === 0) {
      this.cursor = this.value.length - 1;
    } else {
      this.cursor--;
    }

    this.render();
  }

  down() {
    if (this.cursor === this.value.length - 1) {
      this.cursor = 0;
    } else {
      this.cursor++;
    }

    this.render();
  }

  left() {
    this.value[this.cursor].selected = false;
    this.render();
  }

  right() {
    if (this.value.filter(e => e.selected).length >= this.maxChoices) return this.bell();
    this.value[this.cursor].selected = true;
    this.render();
  }

  handleSpaceToggle() {
    const v = this.value[this.cursor];

    if (v.selected) {
      v.selected = false;
      this.render();
    } else if (v.disabled || this.value.filter(e => e.selected).length >= this.maxChoices) {
      return this.bell();
    } else {
      v.selected = true;
      this.render();
    }
  }

  toggleAll() {
    if (this.maxChoices !== undefined || this.value[this.cursor].disabled) {
      return this.bell();
    }

    const newSelected = !this.value[this.cursor].selected;
    this.value.filter(v => !v.disabled).forEach(v => v.selected = newSelected);
    this.render();
  }

  _(c, key) {
    if (c === ' ') {
      this.handleSpaceToggle();
    } else if (c === 'a') {
      this.toggleAll();
    } else {
      return this.bell();
    }
  }

  renderInstructions() {
    if (this.instructions === undefined || this.instructions) {
      if (typeof this.instructions === 'string') {
        return this.instructions;
      }

      return '\nInstructions:\n' + `    ${figures.arrowUp}/${figures.arrowDown}: Highlight option\n` + `    ${figures.arrowLeft}/${figures.arrowRight}/[space]: Toggle selection\n` + (this.maxChoices === undefined ? `    a: Toggle all\n` : '') + `    enter/return: Complete answer`;
    }

    return '';
  }

  renderOption(cursor, v, i) {
    const prefix = (v.selected ? color.green(figures.radioOn) : figures.radioOff) + '  ';
    let title, desc;

    if (v.disabled) {
      title = cursor === i ? color.gray().underline(v.title) : color.strikethrough().gray(v.title);
    } else {
      title = cursor === i ? color.cyan().underline(v.title) : v.title;

      if (cursor === i && v.description) {
        desc = ` - ${v.description}`;

        if (prefix.length + title.length + desc.length >= this.out.columns || v.description.split(/\r?\n/).length > 1) {
          desc = '\n' + wrap(v.description, {
            margin: prefix.length,
            width: this.out.columns
          });
        }
      }
    }

    return prefix + title + color.gray(desc || '');
  } // shared with autocompleteMultiselect


  paginateOptions(options) {
    const c = this.cursor;
    let styledOptions = options.map((v, i) => this.renderOption(c, v, i));
    const numOfOptionsToRender = 10; // if needed, can add an option to change this.

    let scopedOptions = styledOptions;
    let hint = '';

    if (styledOptions.length === 0) {
      return color.red('No matches for this query.');
    } else if (styledOptions.length > numOfOptionsToRender) {
      let startIndex = c - numOfOptionsToRender / 2;
      let endIndex = c + numOfOptionsToRender / 2;

      if (startIndex < 0) {
        startIndex = 0;
        endIndex = numOfOptionsToRender;
      } else if (endIndex > options.length) {
        endIndex = options.length;
        startIndex = endIndex - numOfOptionsToRender;
      }

      scopedOptions = styledOptions.slice(startIndex, endIndex);
      hint = color.dim('(Move up and down to reveal more choices)');
    }

    return '\n' + scopedOptions.join('\n') + '\n' + hint;
  } // shared with autocomleteMultiselect


  renderOptions(options) {
    if (!this.done) {
      return this.paginateOptions(options);
    }

    return '';
  }

  renderDoneOrInstructions() {
    if (this.done) {
      const selected = this.value.filter(e => e.selected).map(v => v.title).join(', ');
      return selected;
    }

    const output = [color.gray(this.hint), this.renderInstructions()];

    if (this.value[this.cursor].disabled) {
      output.push(color.yellow(this.warn));
    }

    return output.join(' ');
  }

  render() {
    if (this.closed) return;
    if (this.firstRender) this.out.write(cursor.hide);
    super.render(); // print prompt

    let prompt = [style.symbol(this.done, this.aborted), color.bold(this.msg), style.delimiter(false), this.renderDoneOrInstructions()].join(' ');

    if (this.showMinError) {
      prompt += color.red(`You must select a minimum of ${this.minSelected} choices.`);
      this.showMinError = false;
    }

    prompt += this.renderOptions(this.value);
    this.out.write(this.clear + prompt);
    this.clear = clear(prompt);
  }

}

module.exports = MultiselectPrompt;