import { PackBuilder, Cube, DraftOptions } from ".";
import EventEmitter from "eventemitter3";
import { Card } from "@/mlpccg";
import { Pack, Direction } from "./types";
import { DraftProvider } from "./provider";
import { DraftBot } from "./bot";
import { I8PCube } from "./i8pcube";

export class Session extends EventEmitter {
  private options: DraftOptions;
  private provider: DraftProvider;
  private pod: SessionPlayer[] = [];
  private players: string[] = [];
  private pending: number[] = [];
  private assigned: boolean = false;
  private direction: Direction = "cw";

  constructor(options: DraftOptions, provider: DraftProvider) {
    super();
    this.options = options;
    this.provider = provider;
    this.pod = new Array(options.players).fill(0).map((x, i) => {
      const player = new SessionPlayer(provider.getPacks());
      player.on("pick", this.picked.bind(this, i));
      return player;
    });
    // Populate prev/next references
    this.pod.forEach((val, i) => {
      if (i > 0) {
        val.prev = this.pod[i - 1];
      } else {
        val.prev = this.pod[this.pod.length - 1];
      }
      if (i < this.pod.length - 1) {
        val.next = this.pod[i + 1];
      } else {
        val.next = this.pod[0];
      }
    });
  }

  public assign(
    players: string[],
    assignFn: (name: string, instance: SessionPlayer) => void
  ) {
    // Figure out how many players there are vs spots to be filled
    this.players = players;
    const spots = this.options.players;
    const playerNum = players.length;
    if (playerNum > spots) {
      throw new Error("too many players in the pod");
    }

    if (playerNum < 1) {
      throw new Error("not enough players");
    }

    // Place players in the pod
    switch (this.options.spacing) {
      case "evenly": {
        const playerRatio = spots / playerNum;
        let i = 0;
        for (const player of players) {
          const pos = Math.floor(playerRatio * i);
          this.pod[pos].name = player;
          assignFn(player, this.pod[pos]);
          i += 1;
        }
        break;
      }
      case "randomly":
        for (const player of players) {
          const free = [...Array(spots).keys()].filter(
            i => this.pod[i].name == ""
          );
          const idx = Math.floor(Math.random() * free.length);
          const chosen = free[idx];
          assignFn(player, this.pod[chosen]);
        }
        break;
    }

    // All the non-assigned places go to bots!
    this.pod.forEach(p => {
      if (p.name == "") {
        p.name = "bot";
        const bot = new DraftBot();
        bot.assign(p);
      }
    });

    this.assigned = true;
  }

  public start() {
    if (!this.assigned) {
      throw new Error("Must assign players first (see assign())");
    }
    this.emit("start", this.order);
    this.nextPack();
  }

  public get order(): string[] {
    return this.pod.map(p => p.name);
  }

  private picked(
    playerIndex: number,
    _card: string,
    lastPick: boolean,
    lastPack: boolean
  ) {
    if (!this.pending.includes(playerIndex)) {
      // Uh oh.
      throw new Error(
        `unexpected pick: player "${this.pod[playerIndex].name}" already picked their card`
      );
    }
    const idx = this.pending.indexOf(playerIndex);
    this.pending.splice(idx, 1);

    this.emit("player-pick", this.pod[playerIndex].name);

    // Don't continue unless everyone picked their card
    if (this.pending.length > 0) {
      return;
    }

    // Was this the last pick for this round of packs?
    if (lastPick) {
      // Was the it the last pack?
      if (lastPack) {
        this.emit("draft-over");
        this.pod.forEach(p => p.emit("your-picks", p.picks));
        return;
      }
      this.nextPack();
      return;
    }

    // Pass packs between players for next pick
    this.resetPending();
    this.pod.forEach(p => p.sendPack(this.direction));
    this.emit("next-pick");
  }

  private nextPack() {
    this.resetPending();
    this.flipOrder();
    this.pod.forEach(p => p.nextPack());
    this.emit("next-pack");
  }

  private resetPending() {
    this.pending = this.pod.map((_, i) => i);
  }

  private flipOrder() {
    if (this.direction == "cw") {
      this.direction = "ccw";
    } else {
      this.direction = "cw";
    }
  }

  static async create(options: DraftOptions): Promise<Session> {
    switch (options.source) {
      case "set": {
        const factory = await PackBuilder.fromSet(options.set);
        const provider = DraftProvider.set(factory, options.packs);
        return new Session(options, provider);
      }
      case "block":
        throw new Error("not implemented");
      case "cube": {
        const cube = await Cube.fromURL(options.url);
        const factory = new PackBuilder(cube.schema());
        const provider = DraftProvider.set(factory, options.packs);
        return new Session(options, provider);
      }
      case "i8pcube": {
        const cube = await I8PCube.fromURL(options.url);
        const provider = new DraftProvider(cube.schema());
        return new Session(options, provider);
      }
      default:
        throw new Error("Unknown draft source");
    }
  }
}

export class SessionPlayer extends EventEmitter {
  public name: string = "";
  public currentPack?: Pack;
  public picks: Pack;
  public packs: Pack[];
  public toSend: Pack | null = null;
  public next?: SessionPlayer;
  public prev?: SessionPlayer;
  public ready: boolean = false;

  constructor(packs: Pack[]) {
    super();
    this.packs = packs;
    this.picks = [];
  }

  public pick(card: string) {
    if (!this.ready) {
      throw new Error("not ready to pick");
    }
    if (!this.currentPack) {
      throw new Error("no pack to pick from");
    }
    const idx = this.currentPack.findIndex(c => c.ID == card);
    if (idx < 0) {
      throw new Error("card not in available picks");
    }
    const pick = this.currentPack.splice(idx, 1);
    this.picks.push(pick[0]);
    this.toSend = this.currentPack;
    this.ready = false;

    this.emit("pick", card, this.currentPack.length < 1, this.packs.length < 1);
  }

  public sendPack(direction: Direction) {
    if (!this.toSend) {
      throw new Error("no pack to pass");
    }
    if (this.toSend.length < 1) {
      throw new Error("empty pack");
    }
    if (direction == "cw") {
      if (!this.next) {
        throw new Error("no player to pass cards to");
      }
      this.next.receivePack(this.toSend);
    } else {
      if (!this.prev) {
        throw new Error("no player to pass cards to");
      }
      this.prev.receivePack(this.toSend);
    }
    this.toSend = null;
  }

  public receivePack(cards: Pack) {
    this.currentPack = cards;
    this.ready = true;
    this.emit("available-picks", cards);
  }

  public nextPack() {
    // Open new pack
    const newPack = this.packs.shift();
    if (!newPack) {
      throw new Error("no packs left");
    }
    this.receivePack(newPack);
  }
}