// What happened while you were away, as a few facts before the reel:
// read from the missed steps as the server redacted them for you, so it
// tells you only what you would have seen at the table.

import type { GameEvent, GameView } from "@wizwar/engine";
import { cardName } from "./reference";

/** One step of a replayed stretch: who acted, what happened, the table
 * after, and any talk that landed alongside. */
export interface ReplayStep {
  seq: number;
  actor: string;
  events: GameEvent[];
  view: GameView;
  chat?: { player: string; text: string }[];
}

export interface MissedFact {
  text: string;
  /** The step of the reel this fact belongs to. */
  step: number;
}

function spell(id: string | null): string {
  return id ? cardName(id) : "a punch";
}

function nearHome(view: GameView, you: string, cell: { x: number; y: number }): boolean {
  const me = view.players.find((p) => p.id === you);
  if (!me) return false;
  return Math.abs(me.home.x - cell.x) + Math.abs(me.home.y - cell.y) <= 2;
}

/** The facts of the missed steps that touch you, in order, capped so the
 * slip stays a slip. Each fact points at its step for the reel. */
export function summarizeMissed(steps: readonly ReplayStep[], you: string, now: GameView | null): MissedFact[] {
  const facts: MissedFact[] = [];
  let lifeLost = 0;
  let lifeLostStep = -1;
  let talk = 0;
  steps.forEach((s, i) => {
    talk += s.chat?.length ?? 0;
    for (const e of s.events) {
      switch (e.type) {
        case "treasurePickedUp":
          if (e.owner === you && e.player !== you) facts.push({ text: `${e.player} took your treasure.`, step: i });
          else if (e.player !== you && e.owner !== e.player) facts.push({ text: `${e.player} picked up ${e.owner}'s treasure.`, step: i });
          break;
        case "treasureDropped": {
          const owner = s.view.treasures.find((t) => t.id === e.treasureId)?.owner;
          if (e.onHomeOf != null && owner && e.onHomeOf !== owner) {
            facts.push({ text: owner === you ? `Your treasure was carried home by ${e.player}.` : `${e.player} carried ${owner}'s treasure home.`, step: i });
          }
          break;
        }
        case "damaged":
          if (e.player === you && e.amount > 0) { lifeLost += e.amount; if (lifeLostStep < 0) lifeLostStep = i; }
          break;
        case "spellCast":
          if (e.target === you) facts.push({ text: `${e.caster} cast ${spell(e.cardId)} at you.`, step: i });
          break;
        case "punched":
          if (e.target === you) facts.push({ text: `${e.attacker} punched you.`, step: i });
          break;
        case "wallDestroyed":
          if (nearHome(s.view, you, e.edge.cell)) facts.push({ text: "A wall near your home was destroyed.", step: i });
          break;
        case "playerEliminated":
          facts.push({ text: e.player === you ? "You were eliminated." : `${e.player} is out of the game.`, step: i });
          break;
        case "gameWon":
          facts.push({ text: e.player === you ? "You won." : `${e.player} won the game.`, step: i });
          break;
        case "tableTalk":
          talk++;
          break;
        default:
          break;
      }
    }
  });
  // Life lost reads second: the first fact names who came for you.
  if (lifeLost > 0) facts.splice(Math.min(facts.length, 1), 0, { text: `You lost ${lifeLost} life.`, step: lifeLostStep });
  if (facts.length === 0) {
    // Nothing touched you: say what each wizard was up to, all the same.
    const doings = new Map<string, { moves: number; casts: number; first: number }>();
    steps.forEach((s, i) => {
      if (s.actor === you) return;
      const d = doings.get(s.actor) ?? { moves: 0, casts: 0, first: i };
      for (const e of s.events) {
        if (e.type === "moved" && e.player === s.actor) d.moves++;
        if (e.type === "spellCast" && e.caster === s.actor) d.casts++;
      }
      doings.set(s.actor, d);
    });
    for (const [who, d] of doings) {
      const bits = [d.moves > 0 ? `walked ${d.moves} square${d.moves === 1 ? "" : "s"}` : "", d.casts > 0 ? `cast ${d.casts} spell${d.casts === 1 ? "" : "s"}` : ""].filter(Boolean);
      facts.push({ text: `${who} ${bits.length ? bits.join(" and ") : "passed the time"}; nothing touched you.`, step: d.first });
    }
  }
  if (talk > 0) facts.push({ text: `${talk} line${talk === 1 ? "" : "s"} of table talk.`, step: -1 });
  const out = facts.slice(0, 6);
  if (facts.length > 6) out.push({ text: `…and ${facts.length - 6} more.`, step: -1 });
  if (now) {
    const me = now.players.find((p) => p.id === you);
    if (now.phase === "playing" && me?.alive) {
      const mine = now.activePlayerId === you || now.stack?.waitingOn === you || now.pendingDiscard === you;
      out.push({ text: mine ? "It's your turn." : `It's ${now.activePlayerId}'s turn.`, step: -1 });
    }
  }
  return out;
}