// THE COACHING DRILL — the cognitive mode. Second design, after Oliver played the first:
//
//   "daniel announcing is maximum annoying"
//   "don't let the rush in position just let them coming from the back in steady speed..
//    try to space them not too close"
//   "when one combination is done just let the new one in.. in a continuous stream that
//    increases in speed and difficulty" / "the rounds can stay, they should be continuous"
//
// So the ROUND survives as the unit — a called combination, put down in order, counted — and every
// SEAM around it is gone: no walk-on to a mark, no announcement beat, no between-rounds pause, no
// deal. Bodies walk in from the far baseline at a steady speed for as long as the mode runs, and a
// round is drawn from whoever happens to be on court. Finish one and the next is drawn on the spot,
// out of the same rolling population — the bodies you were ignoring a second ago are the ones being
// called now. Speed, spawn rate and combination length all ramp with time survived, so the stream
// IS the difficulty curve.
//
// THE MODE TRANSITIONS ARE NOT HERE — startDrill/endDrill live in beats.js with every other one
// (CLAUDE.md rule 3). This file is the stream, the round and the rules. It imports no renderer:
// render.js reads DRILL_COLS and draws.

import { TUNE } from './config.js';
import { G } from './state.js';
import { zombies, spawnZombie } from './zombies.js';
import { voice } from './audio.js';

// The colours. Six, and a colour is on court at most once, so a colour always names exactly one body.
//
// THE MODE HAS NO SOUND OF ITS OWN, and that is now deliberate. Two attempts have been vetoed: the
// recorded umpire reading the list aloud ("daniel announcing is maximum annoying" — at ~0.8 s a word
// he needed four seconds for a list of four, over and over), and the arpeggio that replaced him
// ("no bleeps please"). What is left is the game's own vocabulary: a kill bursts and splats like
// every other kill in the game, and the strip carries the list. Do not put a third noise here
// without a reason — the two that were tried both read as the mode talking over itself.
//
// THERE IS NO REDUNDANT CHANNEL ANY MORE, and that is a known accessibility gap rather than an
// oversight. Die-face dots rode on the bib and the HUD chip so the mode could be played without
// separating red from green (~8% of men cannot) — but they were noise to everyone who can, and they
// shrank to nothing on a body at distance, which is exactly where the channel had to work. Cut on
// Oliver's call. If the mode ships, the answer is bibs that differ by SHAPE or marking at sprite
// scale, not dots: a channel that fails at the far baseline is not a channel.
export const DRILL_COLS = [
  { key: 'red',    col: '#e5342c', name: 'RED' },
  { key: 'blue',   col: '#2f6bff', name: 'BLUE' },
  { key: 'yellow', col: '#f2c318', name: 'YELLOW' },
  { key: 'green',  col: '#27bd4a', name: 'GREEN' },
  { key: 'purple', col: '#9b3fd8', name: 'PURPLE' },
  { key: 'white',  col: '#f2f0e8', name: 'WHITE' },
];

// ---- THE RAMP. One number, 0..1 off time survived; everything else is a lerp on it. Time, not
// rounds won: a round-counted ramp cannot escalate while you stand still.
const ramp = d => Math.min(1, d.t / TUNE.drillRampT);
const lerp = (a, b, k) => a + (b - a) * k;
export const drillSpeed = d => lerp(TUNE.drillSpeed, TUNE.drillSpeedMax, ramp(d));
const batchSize = d => Math.round(lerp(TUNE.drillBatch, TUNE.drillBatchMax, ramp(d)));
const eaterGap = d => lerp(TUNE.drillEaterEvery, TUNE.drillEaterMin, ramp(d));

const shuffle = a => { for (let i = a.length - 1; i > 0; i--) { const j = Math.floor(Math.random() * (i + 1)); [a[i], a[j]] = [a[j], a[i]]; } return a; };
const bibs = () => zombies.filter(z => z.bib !== undefined);

// ---- THE BATCH IS THE ROUND, AND IT IS WHAT MAKES THE MODE WINNABLE. Oliver: "make the game that
// it is actually winable meaning that all required colors are visible on the far side before when a
// color combination is shown.. for now no colors that are not in the current combination".
//
// Two rules follow from that and they are the whole shape of this file now:
//   1. every colour on court is IN the current combination. There are no coloured decoys — so a
//      colour you can see is a colour you will be asked for, and the strip can never name a body
//      that is not there.
//   2. a combination is only ever shown once its bodies are ALL standing on the far side, which is
//      free here because the batch is born there: they walk the full length of the court at you,
//      and that length is the time you are given to work through the list.
// The pressure moved to the EATERS below instead, which is a better place for it — the puzzle stays
// fair and the danger is a separate thing arriving on its own clock.
function spawnBatch(d) {
  const k = Math.min(DRILL_COLS.length, batchSize(d));
  // distinct colours, distinct lanes, fanned across the width and shuffled so the called order has
  // nothing to do with the left-to-right order
  const cols = shuffle(DRILL_COLS.map((_, i) => i)).slice(0, k);
  const lanes = shuffle(cols.map((_, i) => -TUNE.drillSpread + (2 * TUNE.drillSpread) * (i / Math.max(1, k - 1))));
  cols.forEach((bib, i) => {
    // staggered in depth as well as across, so the batch arrives as a loose group rather than as a
    // rank walking in abreast — but every one of them still starts on the far side, which is the
    // promise the mode now makes.
    spawnZombie(lanes[i] + (Math.random() - 0.5) * 0.4,
                TUNE.drillSpawnZ + Math.random() * TUNE.drillBatchDepth, Math.random() < 0.25 ? 'b' : 'a');
    const zb = zombies[zombies.length - 1];
    zb.bib = bib;
    zb.drill = true;                 // holds its lane (see updateZombies) — the lane is the puzzle
    zb.v = drillSpeed(d) * (0.92 + Math.random() * 0.16);
  });
  newRound(d);
}

// ---- THE EATERS. Plain, unbibbed shamblers on their own clock: no colour, no place in any
// combination, nothing to remember about them. Killing one is never a fault (drillKill ignores a
// body with no bib) and letting one reach you is the ordinary caught. They exist because with the
// puzzle made fair the mode needed its danger back from somewhere, and a threat you simply have to
// DEAL WITH is a cleaner source of it than a puzzle that cheats.
// Deliberately NOT flagged `drill`, so they keep the gore mode's homing: they converge on you while
// the bibbed batch walks its lanes, which is exactly the "stop what you are doing" interruption the
// mode was missing.
function spawnEater(d) {
  if (zombies.filter(z => z.bib === undefined).length >= TUNE.drillEaterMax) return;
  spawnZombie((Math.random() * 2 - 1) * TUNE.drillSpread, TUNE.drillSpawnZ + Math.random() * 0.8,
              Math.random() < 0.3 ? 'b' : 'a');
  const zb = zombies[zombies.length - 1];
  zb.v = drillSpeed(d) * TUNE.drillEaterSpeed * (0.9 + Math.random() * 0.2);
}

// ---- THE ROUND: the order the batch has to be taken in. Drawn from every bibbed body on court,
// which — see rule 1 above — is exactly the batch and nothing else.
function newRound(d) {
  const pool = bibs();
  d.step = 0; d.faults = 0;
  d.seq = pool.length ? shuffle(pool.map(z => z.bib)) : [];
  // (no sound: the strip IS the call — see the note on DRILL_COLS)
}

// Called by beats.startDrill once the court is its own.
export function startDrillStream() {
  const d = G.drill; if (!d) return;
  zombies.length = 0;
  d.seq = []; d.step = 0; d.faults = 0; d.t = 0; d.eaterT = TUNE.drillEaterEvery; d.rounds = 0; d.lost = 0; d.msg = null;
  spawnBatch(d);   // the mode has to be whole the moment it starts — a batch on the far side and a
                   // combination already called off it
}

export function updateDrill(dt) {
  const d = G.drill; if (!d) return;
  d.t += dt;
  if (d.msg) d.msg.t -= dt;
  // the eaters keep coming on their own clock, independently of the puzzle
  if ((d.eaterT -= dt) <= 0) { spawnEater(d); d.eaterT = eaterGap(d) * (0.75 + Math.random() * 0.5); }
  // THE CONTINUOUS PART. The batch is the round; kill the last of it and the next batch walks in on
  // the same frame with its combination already called. No pause, no deal, no announcement beat —
  // and because a batch is born on the far side, "all the colours are visible before you are asked
  // for them" holds by construction rather than by a check that could be wrong.
  if (!bibs().length) { spawnBatch(d); return; }
  if (!d.seq.length) newRound(d);   // survivors after a double fault: same bodies, fresh order
}

// A drill body went down. Called from killZombie — the single kill funnel — so no weapon path can
// miss it (the bug this codebase has had twice).
export function drillKill(zb) {
  const d = G.drill; if (!d || zb.bib === undefined) return;
  if (zb.bib === d.seq[d.step]) {
    d.step++;
    // no tick here either — killZombie is already bursting the body and playing the splat, and that
    // burst is a far better "yes, that one" than a beep laid over the top of it
    if (d.step >= d.seq.length) {            // round complete — and the next one is already here
      d.rounds++;
      d.msg = { text: 'GOOD', t: 0.9 };
      newRound(d);
    }
    return;
  }
  // Wrong body — one never called, or one due later. It is dead either way, so drop it from the list
  // rather than leaving a slot nobody can fill: an un-winnable round reads as a broken game, and the
  // fault below is the punishment already.
  d.faults++;
  d.seq = d.seq.filter((c, i) => i < d.step || c !== zb.bib);
  if (d.faults >= 2) {
    d.lost++;
    voice('double_fault', 0.1);
    d.msg = { text: 'DOUBLE FAULT', t: 1.6, bad: true };
    return newRound(d);                      // scrubbed, and a fresh one off the same court
  }
  voice('fault', 0.1);
  d.msg = { text: 'FAULT', t: 1.2, bad: true };
  if (d.step >= d.seq.length) { d.rounds++; newRound(d); } // the wrong kill was the last one outstanding
}

// A drill body reached you. Called from killPlayer, the single death path for BOTH damage channels.
// Contact costs the POINT and a cleared court, never the run: permadeath is settled for the gore
// mode, and a memory game where one lapse deletes a long run punishes the skill it is teaching.
// This is the ONE thing that interrupts the stream, which is exactly what makes it read as a setback.
export function drillCaught() {
  const d = G.drill;
  d.lost++;
  voice('game_opponent', 0.1);
  d.msg = { text: 'CAUGHT', t: 1.8, bad: true };
  zombies.length = 0;
  d.seq = []; d.step = 0; d.faults = 0; d.spawnT = 0;
  d.t = Math.max(0, d.t - TUNE.drillCaughtBack);  // ...and the ramp backs off a little
}

// Which body is owed right now — the HUD highlights it. NOT used for aiming: the auto-aim is gone.
export const drillTarget = () => zombies.find(z => G.drill && z.bib === G.drill.seq[G.drill.step]) || null;