const grid = document.getElementById("service-grid");
const modalBackdrop = document.getElementById("service-modal-backdrop");
const modalClose = document.getElementById("service-modal-close");
const modalTitle = document.getElementById("service-modal-title");
const modalCategory = document.getElementById("service-modal-category");
const modalGrid = document.getElementById("service-modal-grid");

const services = new Map();
const tiles = new Map();
let openServiceName = "";
let socket = null;
let reconnectTimer = 0;

function formatTimestamp(value) {
  const date = new Date(value);
  return date.toLocaleString(undefined, {
    month: "short",
    day: "numeric",
    year: "numeric",
    hour: "numeric",
    minute: "2-digit",
    second: "2-digit",
    timeZoneName: "short"
  });
}

function formatTime(value) {
  const date = new Date(value);
  return date.toLocaleTimeString(undefined, {
    hour: "numeric",
    minute: "2-digit",
    second: "2-digit"
  });
}

function escapeHTML(value) {
  return String(value).replace(/[&<>"']/g, function(char) {
    const entities = {
      "&": "&amp;",
      "<": "&lt;",
      ">": "&gt;",
      '"': "&quot;",
      "'": "&#39;"
    };
    return entities[char];
  });
}

function sortServices(items) {
  return items.sort(function(a, b) {
    if (a.healthy === b.healthy) {
      return a.name.localeCompare(b.name);
    }
    return a.healthy ? -1 : 1;
  });
}

function serviceTile(service) {
  const tile = document.createElement("article");
  tile.className = "tile tile-enter";
  tile.dataset.serviceName = service.name;
  tile.innerHTML =
    '<div class="row">' +
      '<span class="category"></span>' +
      '<span class="pill"><span class="dot"></span><span class="pill-label"></span></span>' +
    '</div>' +
    '<h2 class="name"></h2>' +
    '<div class="stats">' +
      '<div class="stat">' +
        '<span class="label">HTTP Status</span>' +
        '<span class="value status-code"></span>' +
      '</div>' +
      '<div class="stat">' +
        '<span class="label">Response Time</span>' +
        '<span class="value response-time"></span>' +
      '</div>' +
    '</div>';

  applyServiceToTile(tile, service);
  tile.setAttribute("role", "button");
  tile.setAttribute("tabindex", "0");
  tile.addEventListener("click", function() {
    openModal(service.name);
  });
  tile.addEventListener("keydown", function(event) {
    if (event.key === "Enter" || event.key === " ") {
      event.preventDefault();
      openModal(service.name);
    }
  });
  window.setTimeout(function() {
    tile.classList.remove("tile-enter");
  }, 500);
  return tile;
}

function applyServiceToTile(tile, service) {
  const pill = tile.querySelector(".pill");
  const pillLabel = tile.querySelector(".pill-label");
  const statusCode = service.status_code > 0 ? service.status_code : "n/a";

  tile.querySelector(".category").textContent = service.category + " · " + String(service.protocol || "").toUpperCase();
  tile.querySelector(".name").textContent = service.name;
  tile.querySelector(".status-code").textContent = statusCode;
  tile.querySelector(".response-time").textContent = service.response_time;

  pill.classList.toggle("ok", service.healthy);
  pill.classList.toggle("bad", !service.healthy);
  pillLabel.textContent = service.healthy ? "Healthy" : "Down";
}

function modalField(label, value) {
  return '<div class="modal-stat">' +
    '<span class="label">' + escapeHTML(label) + '</span>' +
    '<span class="value">' + escapeHTML(value) + '</span>' +
  '</div>';
}

function renderModal(service) {
  const statusCode = service.status_code > 0 ? String(service.status_code) : "n/a";
  modalCategory.textContent = service.category + " · " + String(service.protocol || "").toUpperCase();
  modalTitle.textContent = service.name;
  modalGrid.innerHTML =
    modalField("Status", service.healthy ? "Healthy" : "Down") +
    modalField("URL", service.url || "n/a") +
    modalField("HTTP Status", statusCode) +
    modalField("Response Time", service.response_time || "n/a") +
    modalField("Last Checked", formatTimestamp(service.last_checked)) +
    modalField("Message", service.message || "n/a") +
    modalField("Details", service.details || "n/a") +
    modalField("Category", service.category || "n/a") +
    modalField("Protocol", String(service.protocol || "").toUpperCase() || "n/a");
}

function openModal(serviceName) {
  const service = services.get(serviceName);
  if (!service) {
    return;
  }

  openServiceName = serviceName;
  renderModal(service);
  modalBackdrop.classList.remove("hidden");
  document.body.classList.add("modal-open");
}

function closeModal() {
  openServiceName = "";
  modalBackdrop.classList.add("hidden");
  document.body.classList.remove("modal-open");
}

function syncGridOrder(items) {
  items.forEach(function(service) {
    let tile = tiles.get(service.name);
    if (!tile) {
      tile = serviceTile(service);
      tiles.set(service.name, tile);
    } else {
      applyServiceToTile(tile, service);
    }

    grid.appendChild(tile);
  });
}

function syncTiles(items) {
  const liveNames = new Set(items.map(function(service) {
    return service.name;
  }));

  Array.from(tiles.keys()).forEach(function(name) {
    if (!liveNames.has(name)) {
      const tile = tiles.get(name);
      if (tile) {
        tile.remove();
      }
      tiles.delete(name);
    }
  });
}

function renderSnapshot() {
  const items = sortServices(Array.from(services.values()));
  if (items.length === 0) {
    grid.replaceChildren();
    return;
  }

  syncTiles(items);
  syncGridOrder(items);
}

function upsertService(service) {
  services.set(service.name, service);

  const items = sortServices(Array.from(services.values()));
  syncGridOrder(items);

  if (openServiceName === service.name) {
    renderModal(service);
  }
}

function scheduleReconnect() {
  if (reconnectTimer) {
    return;
  }

  reconnectTimer = window.setTimeout(function() {
    reconnectTimer = 0;
    connectWebSocket();
  }, 2000);
}

function connectWebSocket() {
  const protocol = window.location.protocol === "https:" ? "wss:" : "ws:";
  socket = new WebSocket(protocol + "//" + window.location.host + "/ws");

  socket.addEventListener("open", function() {
    loadInitialStatus().catch(function(error) {
      console.error("Failed to reload status after websocket reconnect:", error);
    });
  });

  socket.addEventListener("message", function(event) {
    const payload = JSON.parse(event.data);

    if (payload.type === "service_update" && payload.service) {
      upsertService(payload.service);
    }
  });

  socket.addEventListener("close", function() {
    socket = null;
    scheduleReconnect();
  });

  socket.addEventListener("error", function() {
    socket.close();
  });
}

modalClose.addEventListener("click", closeModal);
modalBackdrop.addEventListener("click", function(event) {
  if (event.target === modalBackdrop) {
    closeModal();
  }
});
document.addEventListener("keydown", function(event) {
  if (event.key === "Escape" && !modalBackdrop.classList.contains("hidden")) {
    closeModal();
  }
});

function loadInitialStatus() {
  return fetch("/api/status", {
    headers: {
      "Accept": "application/json"
    }
  }).then(function(response) {
    if (!response.ok) {
      throw new Error("Request failed with status " + response.status);
    }

    return response.json();
  }).then(function(payload) {
    services.clear();
    (payload.services || []).forEach(function(service) {
      services.set(service.name, service);
    });
    renderSnapshot();
  });
}

loadInitialStatus().finally(function() {
  connectWebSocket();
});