// Brawler: aggressive pressure. Closes in while firing, and steps out of shots and areas it can see.
// Up close it lines up a slam (a wall behind the enemy), and the stun sets up a shot that can't miss.
import { chooseAttack, endTile, evadeDanger, cheb, inSafeZone, pickupStep, searchGoal, shove, stepToward, watchEnemy, type Ctx, type Observation, type Policy, type Turn } from "../lib/bot.ts";

/** Movement phase. */
function movement(obs: Observation, ctx: Ctx): Turn {
  const escape = evadeDanger(obs);
  if (escape) return escape;
  const pos = obs.self.pos;
  const cd = obs.self.cooldowns;
  const enemy = obs.enemies[0];
  if (cd.move !== 0) return {};

  // The zone comes first, before the enemy or a pickup: walk back toward the centre.
  if (!inSafeZone(obs, pos)) {
    const d = stepToward(ctx.map, pos, obs.zone.center, 0, enemy ? [enemy.pos] : []);
    if (d) return { move: d };
  }

  // Pickups are free to take: detour for a nearby one, farther when nobody is in sight.
  const grab = pickupStep(obs, ctx, enemy ? 3 : 8);
  if (grab) return { move: grab };

  if (!enemy) {
    const d = stepToward(ctx.map, pos, searchGoal(obs, ctx), 1);
    return d ? { move: d } : {};
  }

  // Combo setup: with the repulsor ready, stand on the side of the enemy that puts a wall behind them.
  const dist = cheb(pos, enemy.pos);
  if (cd.repulsor === 0 && dist <= 2) {
    const push = ctx.hello.rules.attacks.repulsor.push;
    if (dist === 1 && shove(ctx.map, pos, enemy.pos, push).slam) return {};
    const spot = obs.moves.find((m) => cheb(m.tile, enemy.pos) === 1 && shove(ctx.map, m.tile, enemy.pos, push).slam);
    if (spot) return { move: spot.dir };
  }

  // Close the distance: always when far or when the guns are cooling, sometimes when near.
  if (dist > 2 && (dist > 4 || cd.ranged !== 0 || ctx.rand() < 0.3)) {
    const d = stepToward(ctx.map, pos, enemy.pos, 2, [enemy.pos]);
    if (d) return { move: d };
  }
  return {};
}

/** A line to shout when it slams the enemy into a wall (talking is free, so it never costs a move). */
function taunt(obs: Observation): string | undefined {
  const slam = obs.events.some((e) => e.kind === "wall_slam" && e.attacker === obs.self.id);
  return slam && obs.self.cooldowns.shout === 0 ? "Say hello to the wall!" : undefined;
}

export const brawler: Policy = {
  version: "brawler-18",
  decide(obs, ctx): Turn {
    watchEnemy(obs, ctx);
    const shout = taunt(obs);
    if (obs.self.state !== "idle") return shout ? { shout } : {};
    const turn = movement(obs, ctx);
    const attack = chooseAttack(obs, ctx, endTile(obs, turn));
    if (attack) turn.attack = attack;
    if (shout) turn.shout = shout;
    return turn;
  },
};