const BOARD_SIZE = 10;

const state = {
  fleetDef: [],
  selectedShip: null,
  orientation: "h",
  status: "placing",
};

const el = (id) => document.getElementById(id);

const CAP_COLORS = ["#c0392b", "#2980b9", "#27ae60", "#8e44ad", "#d35400", "#16a085", "#f1c40f", "#c2185b"];
function capColorFor(row, col) {
  return CAP_COLORS[(row * 7 + col * 3) % CAP_COLORS.length];
}

async function api(path, options) {
  const res = await fetch(path, {
    method: options?.method || "GET",
    headers: { "Content-Type": "application/json" },
    body: options?.body ? JSON.stringify(options.body) : undefined,
  });
  const data = await res.json();
  if (!res.ok) {
    setMessage(data.error || "Fehler", true);
    throw new Error(data.error || "Request failed");
  }
  return data;
}

function setMessage(text, isError = false) {
  const m = el("message");
  m.textContent = text;
  m.style.color = isError ? "#ff8b8b" : "";
}

function wapplerSprite(hat) {
  const wrap = document.createElement("div");
  wrap.className = "wappler";
  wrap.style.setProperty("--hat", hat);
  wrap.innerHTML =
    '<div class="cap"></div><div class="head"></div><div class="brille"></div>' +
    '<div class="grinser"></div><div class="stoppel"></div>';
  return wrap;
}

function buildBoard(container, size, onClick) {
  container.innerHTML = "";
  const cells = [];
  for (let r = 0; r < size; r++) {
    const rowCells = [];
    for (let c = 0; c < size; c++) {
      const cell = document.createElement("div");
      cell.className = "cell";
      cell.dataset.row = r;
      cell.dataset.col = c;
      if (onClick) cell.addEventListener("click", () => onClick(r, c, cell));
      container.appendChild(cell);
      rowCells.push(cell);
    }
    cells.push(rowCells);
  }
  return cells;
}

// ----- Placement screen -----
let placementCells = null;

function renderFleetPicker(data) {
  const picker = el("fleet-picker");
  picker.innerHTML = "";
  const placedIds = new Set();
  for (const row of data.player_board) {
    for (const cell of row) if (cell) placedIds.add(cell);
  }
  for (const ship of data.fleet_def) {
    const btn = document.createElement("button");
    btn.type = "button";
    const isPlaced = placedIds.has(ship.id);
    btn.textContent = `${ship.name} (${ship.size})`;
    btn.style.setProperty("--hat", ship.hat);
    btn.classList.toggle("placed", isPlaced);
    btn.classList.toggle("selected", state.selectedShip === ship.id);
    btn.disabled = isPlaced;
    btn.addEventListener("click", () => {
      state.selectedShip = ship.id;
      renderFleetPicker(data);
    });
    picker.appendChild(btn);
  }
}

function renderPlacementBoard(data) {
  if (!placementCells) {
    placementCells = buildBoard(el("placement-board"), BOARD_SIZE, handlePlacementClick);
  }
  for (let r = 0; r < BOARD_SIZE; r++) {
    for (let c = 0; c < BOARD_SIZE; c++) {
      const cell = placementCells[r][c];
      cell.className = "cell own";
      cell.innerHTML = "";
      const shipId = data.player_board[r][c];
      if (shipId) {
        cell.appendChild(wapplerSprite(capColorFor(r, c)));
      }
    }
  }
  const placedCount = new Set(data.player_board.flat().filter(Boolean)).size;
  el("start-btn").disabled = placedCount !== data.fleet_def.length;
}

async function handlePlacementClick(r, c) {
  if (!state.selectedShip) {
    setMessage("Wähle zuerst einen Wappler aus.", true);
    return;
  }
  try {
    const data = await api("/api/place_ship", {
      method: "POST",
      body: { ship_id: state.selectedShip, row: r, col: c, orientation: state.orientation },
    });
    applyState(data);
    state.selectedShip = null;
  } catch (e) {
    /* message already shown */
  }
}

// ----- Battle screen -----
let ownCells = null;
let enemyCells = null;

function renderBattle(data) {
  if (!ownCells) ownCells = buildBoard(el("own-board"), BOARD_SIZE, null);
  if (!enemyCells) enemyCells = buildBoard(el("enemy-board"), BOARD_SIZE, handleFireClick);

  for (let r = 0; r < BOARD_SIZE; r++) {
    for (let c = 0; c < BOARD_SIZE; c++) {
      const own = ownCells[r][c];
      own.className = "cell own";
      own.innerHTML = "";
      const shipId = data.player_board[r][c];
      const receivedShot = data.player_shots_received[r][c];
      if (shipId) own.appendChild(wapplerSprite(capColorFor(r, c)));
      if (receivedShot) own.classList.add(receivedShot);

      const enemy = enemyCells[r][c];
      enemy.className = "cell";
      enemy.innerHTML = "";
      const madeShot = data.player_shots_made[r][c];
      if (madeShot) enemy.classList.add(madeShot);
    }
  }

  renderFleetStatus(el("own-fleet"), data.player_fleet);
  renderFleetStatus(el("enemy-fleet"), data.computer_fleet);
}

function renderFleetStatus(container, fleet) {
  container.innerHTML = "";
  for (const ship of fleet) {
    const badge = document.createElement("span");
    badge.className = "badge" + (ship.sunk ? " sunk" : "");
    badge.textContent = `${ship.name}`;
    container.appendChild(badge);
  }
}

async function handleFireClick(r, c) {
  if (state.status !== "playing") return;
  try {
    const data = await api("/api/fire", { method: "POST", body: { row: r, col: c } });
    applyState(data);
  } catch (e) {
    /* message already shown */
  }
}

// ----- Shared -----
function applyState(data) {
  state.fleetDef = data.fleet_def;
  state.status = data.status;
  setMessage(data.message);

  const placementScreen = el("placement-screen");
  const battleScreen = el("battle-screen");

  if (data.status === "placing") {
    placementScreen.classList.remove("hidden");
    battleScreen.classList.add("hidden");
    renderFleetPicker(data);
    renderPlacementBoard(data);
  } else {
    placementScreen.classList.add("hidden");
    battleScreen.classList.remove("hidden");
    renderBattle(data);
    el("new-game-btn").classList.toggle(
      "hidden",
      !(data.status === "player_win" || data.status === "computer_win")
    );
  }
}

function init() {
  el("rotate-btn").addEventListener("click", () => {
    state.orientation = state.orientation === "h" ? "v" : "h";
    el("rotate-btn").textContent =
      "🔄 Ausrichtung: " + (state.orientation === "h" ? "horizontal" : "vertikal");
  });

  el("random-btn").addEventListener("click", async () => {
    const data = await api("/api/random_place", { method: "POST" });
    applyState(data);
  });

  el("reset-btn").addEventListener("click", async () => {
    const data = await api("/api/reset_placement", { method: "POST" });
    applyState(data);
  });

  el("start-btn").addEventListener("click", async () => {
    try {
      const data = await api("/api/start", { method: "POST" });
      applyState(data);
    } catch (e) {
      /* message already shown */
    }
  });

  el("new-game-btn").addEventListener("click", async () => {
    const data = await api("/api/new_game", { method: "POST" });
    applyState(data);
  });

  api("/api/state").then(applyState);
}

init();