// Hotseat: the whole game runs in this browser — the engine is pure
// TypeScript, so no server is involved at all. The device is passed between
// players; a hand-off screen keeps hands private between seats. The game
// saves itself after every command (config + command log, replayed on
// resume — the same determinism trick the server uses).

import {
  applyCommand,
  createGame,
  viewFor,
  type Command,
  type GameConfig,
  type GameState,
  type GameView,
  type PlayerId,
  type GameEvent,
  redactEvent,
} from "@wizwar/engine";
import { humanize, net } from "./net.svelte";

const SAVE_KEY = "wizwar-hotseat";

interface SavedHotseat {
  config: GameConfig;
  commands: { playerId: PlayerId; command: Command }[];
  /** Anonymous tally identity + table-time bookkeeping; absent in older saves. */
  tallyId?: string;
  activeMs?: number;
  lastMoveAt?: number;
}

/** Whose input does the game need right now? */
function actorId(state: GameState): PlayerId {
  return (
    state.pendingDiscard ??
    state.outOfTurnWindow?.playerId ??
    state.stack?.waitingOn ??
    state.players[state.turn.activeIndex]!.id
  );
}

class LocalGame {
  active = $state(false);
  /** Hotseat setup round: players name themselves one by one. */
  setup = $state<{ count: number; expansion: boolean; names: PlayerId[]; colors: number[] } | null>(null);
  gameState = $state<GameState | null>(null);
  viewerId = $state<PlayerId | null>(null);
  /** Set while the device should be handed to the named player. */
  handoffTo = $state<PlayerId | null>(null);
  log = $state<string[]>([]);
  /** The opening roll-off, shown once as the boards flip. */
  openingRolls = $state<{ rolls: Record<string, number[]>; first: string; players: string[] } | null>(null);
  /** Board flourishes: the app hooks in to animate command results. */
  onFx: ((events: GameEvent[]) => void) | null = null;
  /** The finished game as a reel, each step from its actor's own seat. */
  replaySteps = $state<{ seq: number; actor: PlayerId; events: GameEvent[]; view: GameView }[] | null>(null);
  view = $derived(
    this.gameState && this.viewerId ? viewFor(this.gameState, this.viewerId) : null,
  );

  private config: GameConfig | null = null;
  private commands: { playerId: PlayerId; command: Command }[] = [];
  private tallyId: string | null = null;
  private activeMs = 0;
  private lastMoveAt = 0;

  /** The tabletop D4 for house calls: chronicle only, no game state. */
  rollTableDie(): void {
    if (!this.viewerId) return;
    const roll = 1 + (crypto.getRandomValues(new Uint32Array(1))[0]! % 4);
    this.log = [...this.log, `\u{1F3B2} ${this.viewerId} rolls the die \u2014 ${roll}`];
  }

  /** Rebuild the whole game as replay steps (finished games only). */
  buildReplay(): void {
    if (!this.config || this.gameState?.phase !== "finished") return;
    const { state } = createGame(this.config);
    let current = state;
    const steps: { seq: number; actor: PlayerId; events: GameEvent[]; view: GameView }[] = [];
    this.commands.forEach((c, i) => {
      const r = applyCommand(current, c.playerId, c.command);
      if (!r.ok) return;
      current = r.state;
      steps.push({
        seq: i,
        actor: c.playerId,
        events: r.events.map((e) => redactEvent(e, c.playerId)).filter((e): e is GameEvent => e !== null),
        view: viewFor(current, c.playerId),
      });
    });
    this.replaySteps = steps;
  }

  hasSave(): boolean {
    return localStorage.getItem(SAVE_KEY) !== null;
  }

  beginSetup(count: number, expansion: boolean): void {
    this.setup = { count, expansion, names: [], colors: [] };
  }

  cancelSetup(): void {
    this.setup = null;
  }

  /** One wizard names themselves and picks a standee; the last starts the game. */
  submitName(raw: string, colorIndex: number): string | null {
    if (!this.setup) return "no setup in progress";
    const name = raw.trim();
    if (!name) return "every wizard needs a name";
    if (this.setup.names.some((n) => n.toLowerCase() === name.toLowerCase())) {
      return "that name is already taken at this table";
    }
    if (this.setup.colors.includes(colorIndex)) {
      return "that wizard has already been claimed";
    }
    this.setup = {
      ...this.setup,
      names: [...this.setup.names, name],
      colors: [...this.setup.colors, colorIndex],
    };
    if (this.setup.names.length === this.setup.count) {
      const { names, expansion, colors } = this.setup;
      this.setup = null;
      return this.start(names, expansion, colors);
    }
    return null;
  }

  start(names: PlayerId[], expansion: boolean, colors?: number[]): string | null {
    const cleaned = [...new Set(names.map((n) => n.trim()).filter(Boolean))];
    if (cleaned.length < 2 || cleaned.length > 6) return "two to six wizards, each with a name";
    const seed = crypto.getRandomValues(new Uint32Array(1))[0]!;
    const config: GameConfig = {
      playerIds: cleaned,
      seed,
      sets: expansion ? ["basic", "expansion1"] : ["basic"],
      ...(colors ? { colors } : {}),
      deckRev: 30,
    };
    const { state, events } = createGame(config);
    for (const e of events) {
      if (e.type === "gameStarted") {
        this.openingRolls = { rolls: e.dieRolls, first: e.firstPlayer, players: e.players };
      }
    }
    this.config = config;
    this.commands = [];
    this.gameState = state;
    this.log = [];
    for (const e of events) {
      const line = humanize(e);
      if (line) this.log = [...this.log, line];
    }
    this.active = true;
    this.viewerId = null;
    this.handoffTo = actorId(state);
    this.tallyId = crypto.randomUUID();
    this.activeMs = 0;
    this.lastMoveAt = Date.now();
    // iOS evicts unprotected origin storage under pressure; ask for durability
    // so a saved hotseat game survives more than a forced reload.
    navigator.storage?.persist?.().catch(() => {});
    net.reportHotseat({ id: this.tallyId, stage: "started", players: cleaned.length });
    this.persist();
    return null;
  }

  resume(): boolean {
    const raw = localStorage.getItem(SAVE_KEY);
    if (!raw) return false;
    try {
      const saved = JSON.parse(raw) as SavedHotseat;
      const { state, events } = createGame(saved.config);
      let current = state;
      this.log = [];
      for (const e of events) {
        const line = humanize(e);
        if (line) this.log = [...this.log, line];
      }
      for (const c of saved.commands) {
        const result = applyCommand(current, c.playerId, c.command);
        if (!result.ok) throw new Error(`replay failed: ${result.error}`);
        current = result.state;
        for (const e of result.events) {
          const line = humanize(e);
          if (line) this.log = [...this.log, line];
        }
      }
      this.config = saved.config;
      this.commands = saved.commands;
      this.tallyId = saved.tallyId ?? crypto.randomUUID();
      this.activeMs = saved.activeMs ?? 0;
      this.lastMoveAt = saved.lastMoveAt ?? Date.now();
      this.gameState = current;
      this.active = true;
      this.viewerId = null;
      navigator.storage?.persist?.().catch(() => {});
      this.handoffTo = actorId(current);
      return true;
    } catch (e) {
      console.error("hotseat resume failed:", e);
      localStorage.removeItem(SAVE_KEY);
      return false;
    }
  }

  /** The named player takes the device: their hand becomes visible. */
  takeSeat(): void {
    if (!this.handoffTo) return;
    this.viewerId = this.handoffTo;
    this.handoffTo = null;
  }

  command(command: Command): void {
    if (!this.gameState || !this.viewerId) return;
    // The engine deep-clones with structuredClone, which cannot handle
    // Svelte's reactive proxies — hand it a plain snapshot.
    const plain = $state.snapshot(this.gameState) as GameState;
    const result = applyCommand(plain, this.viewerId, command);
    if (!result.ok) {
      this.log = [...this.log, `— ${result.error} —`];
      return;
    }
    this.onFx?.(result.events);
    this.gameState = result.state;
    this.commands = [...this.commands, { playerId: this.viewerId, command }];
    const now = Date.now();
    if (this.lastMoveAt && now - this.lastMoveAt < 10 * 60 * 1000) this.activeMs += now - this.lastMoveAt;
    this.lastMoveAt = now;
    if (this.gameState.phase === "finished" && this.tallyId) {
      net.reportHotseat({
        id: this.tallyId, stage: "finished",
        players: this.gameState.players.length,
        commands: this.commands.length,
        minutes: Math.round(this.activeMs / 60_000),
        winReason: this.gameState.winReason ?? undefined,
      });
    }
    for (const e of result.events) {
      const line = humanize(e);
      if (line) this.log = [...this.log, line];
    }
    this.persist();
    if (this.gameState.phase === "playing") {
      const next = actorId(this.gameState);
      if (next !== this.viewerId) this.handoffTo = next;
    }
  }

  /** End the hotseat session (the save survives unless the game is over). */
  leave(): void {
    if (this.gameState?.phase === "finished") localStorage.removeItem(SAVE_KEY);
    this.active = false;
    this.gameState = null;
    this.viewerId = null;
    this.handoffTo = null;
    this.log = [];
  }

  abandon(): void {
    localStorage.removeItem(SAVE_KEY);
    this.leave();
  }

  private persist(): void {
    if (!this.config) return;
    localStorage.setItem(
      SAVE_KEY,
      JSON.stringify({
        config: this.config, commands: this.commands,
        tallyId: this.tallyId ?? undefined, activeMs: this.activeMs, lastMoveAt: this.lastMoveAt,
      } satisfies SavedHotseat),
    );
  }
}

export const local = new LocalGame();