/**
 * player.js
 * Player state, grid movement, and inventory management.
 * No rendering, no DOM — pure logic.
 */

class Player {
  constructor() {
    this.reset();
  }

  reset() {
    // Grid position: col 0-3 (left → right), row 0-2 (top → bottom)
    this.col = 0;
    this.row = 1;

    // Carried goods (max SETTINGS.MAX_CARRY)
    this.goods = [];

    // Whether the player is holding the medication vial
    this.hasMedication = false;

    // Movement cooldown (ms)
    this.moveCooldown = 0;

    // Walk-cycle: phase advances (radians) while moveCooldown > 0
    this.walkPhase = 0;
    this.animFrame = 0;
    this.animTimer  = 0;

    // Flash timer when interacting
    this.interactFlash = 0;
  }

  /* ── Helpers ──────────────────────────────────────────────── */

  /** Pixel x centre of current column inside the middle zone. */
  pixelX() {
    // Evenly distribute columns across the middle zone with a 30px margin
    // from each edge, so col 0 sits just right of the belt end and
    // col (PLAYER_COLS-1) sits just left of the right-zone border.
    const margin = 30;
    const avail  = SETTINGS.MIDDLE_ZONE_END - SETTINGS.MIDDLE_ZONE_START - margin * 2;
    const step   = avail / (SETTINGS.PLAYER_COLS - 1);
    return SETTINGS.MIDDLE_ZONE_START + margin + this.col * step;
  }

  /** Pixel y centre of current row. */
  pixelY() {
    return SETTINGS.BELT_ROWS[this.row];
  }

  canMove() {
    return this.moveCooldown <= 0;
  }

  canCarryMore() {
    return this.goods.length < SETTINGS.MAX_CARRY;
  }

  /* ── Movement ─────────────────────────────────────────────── */

  move(direction) {
    if (!this.canMove()) return false;

    let nc = this.col;
    let nr = this.row;

    switch (direction) {
      case 'up':    nr = Math.max(0, nr - 1); break;
      case 'down':  nr = Math.min(SETTINGS.PLAYER_ROWS - 1, nr + 1); break;
      case 'left':  nc = Math.max(0, nc - 1); break;
      case 'right': nc = Math.min(SETTINGS.PLAYER_COLS - 1, nc + 1); break;
      default: return false;
    }

    if (nc === this.col && nr === this.row) return false;

    this.col = nc;
    this.row = nr;
    this.moveCooldown = SETTINGS.PLAYER_MOVE_COOLDOWN;
    return true;
  }

  /* ── Inventory ────────────────────────────────────────────── */

  /**
   * Attempt to add a good to the inventory.
   * Returns true on success, false if full.
   */
  addGood(good) {
    if (!this.canCarryMore()) return false;
    this.goods.push(good);
    this.interactFlash = 300;
    return true;
  }

  /**
   * Remove and return all carried goods (for lab deposit).
   */
  depositGoods() {
    const deposited = [...this.goods];
    this.goods = [];
    this.interactFlash = 400;
    return deposited;
  }

  pickupMedication() {
    this.hasMedication = true;
    this.interactFlash = 400;
  }

  /**
   * Deliver medication to patient.
   * Returns true if medication was delivered.
   */
  deliverMedication() {
    if (!this.hasMedication) return false;
    this.hasMedication = false;
    this.interactFlash = 600;
    return true;
  }

  /* ── Update ───────────────────────────────────────────────── */

  update(dt) {
    if (this.moveCooldown > 0) {
      this.moveCooldown -= dt;
      // Advance walk cycle: ~π radians per 180 ms move cooldown → one leg swing per step
      this.walkPhase += dt * 0.0175;
    }
    if (this.interactFlash > 0) this.interactFlash -= dt;

    this.animTimer += dt;
    if (this.animTimer >= 200) {
      this.animTimer -= 200;
      this.animFrame = (this.animFrame + 1) % 4;
    }
  }
}