import { doesExist } from '@apextoaster/js-utils';
import { prng } from 'seedrandom';

import { randomItem } from './utils';

/**
 * A reference to another label.
 */
export interface LabelRef {
  name: string;
}

/**
 * A set of labels to add and/or remove.
 */
export interface ChangeSet {
  adds: Array<LabelRef>;
  removes: Array<LabelRef>;
}

/**
 * Common fields for all labels.
 */
export interface BaseLabel {
  /**
   * Label name.
   */
  name: string;

  /**
   * Display color.
   */
  color?: string;

  /**
   * Long-form description.
   */
  desc?: string;

  /**
   * Label priority.
   */
  priority: number;
}

/**
 * Individual labels: the equivalent of a checkbox.
 */
export interface FlagLabel extends BaseLabel, ChangeSet {
  requires: Array<LabelRef>;
}

/**
 * The transition between two state values.
 */
export interface StateChange extends ChangeSet {
  /**
   * Required labels for this state change to occur.
   */
  matches: Array<LabelRef>;
}

/**
 * One of many values for a particular state.
 */
export interface StateValue extends BaseLabel, ChangeSet {
  /**
   * State changes that could occur to this value.
   */
  becomes: Array<StateChange>;
}

/**
 * Grouped labels: the equivalent of a radio group.
 */
export interface StateLabel extends BaseLabel {
  /**
   * Values for this state.
   */
  values: Array<StateValue>;
}

/**
 * Calculate the set of unique names for a list of flags and a list of states, with all state values
 * qualified and included.
 */
export function getLabelNames(flags: Array<FlagLabel>, states: Array<StateLabel>): Set<string> {
  const labels = [];

  for (const flag of flags) {
    labels.push(flag.name);
  }

  for (const state of states) {
    for (const value of state.values) {
      labels.push(getValueName(state, value));
    }
  }

  return new Set(labels);
}

export function splitValueName(name: string): Array<string> {
  return name.split('/');
}

export function getValueName(state: StateLabel, value: StateValue): string {
  return `${state.name}/${value.name}`;
}

/**
 * Sort labels by their priority field, highest first.
 *
 * TODO: add some sort options: high-first or low-first, case-sensitivity
 */
export function prioritySort<TLabel extends BaseLabel>(labels: Array<TLabel>): Array<TLabel> {
  return labels.sort((a, b) => {
    if (a.priority === b.priority) {
      const aName = a.name.toLocaleLowerCase();
      const bName = b.name.toLocaleLowerCase();
      return aName.localeCompare(bName);
    } else {
      // B first for high-to-low
      return b.priority - a.priority;
    }
  });
}

/**
 * Pick a label color, preferring the label data if set, falling back to a randomly selected color.
 */
export function getLabelColor(colors: Array<string>, random: prng, flag: FlagLabel): string;
export function getLabelColor(colors: Array<string>, random: prng, state: StateLabel, value: StateValue): string;
export function getLabelColor(colors: Array<string>, random: prng, label: BaseLabel, value?: StateValue): string {
  if (doesExist(value) && doesExist(value.color) && value.color !== '') {
    return value.color;
  }

  if (doesExist(label.color) && label.color !== '') {
    return label.color;
  }

  return randomItem(colors, random);
}