/* globals: Konva */

// ---------------------------------------------------------------------------
// Constants & mutable state
// ---------------------------------------------------------------------------

const PPM = 60; // pixels per meter

let rooms   = [];   // [{id, name, x, y, width, height}]
let sensors = [];   // [{id, sensor_id, name?, floor_x, floor_y, room_id}]
let mode    = 'view';

let _fittedOnce = false;
let _dragging   = false; // true while any room group is being dragged

// Room currently showing dimension overlay (follows during drag).
let _dimRoom  = null;
let _dimGroup = null;

// ---------------------------------------------------------------------------
// Stage & layers
// ---------------------------------------------------------------------------

const stage = new Konva.Stage({
  container: 'canvas-container',
  width: window.innerWidth,
  height: window.innerHeight,
});
stage.draggable(true);
Konva.hitOnDragEnabled = true;

const roomsLayer      = new Konva.Layer();
const dimensionsLayer = new Konva.Layer();
const sensorsLayer    = new Konva.Layer();
const tagsLayer       = new Konva.Layer();
const particlesLayer  = new Konva.Layer();
stage.add(roomsLayer, dimensionsLayer, sensorsLayer, tagsLayer, particlesLayer);

new ResizeObserver(() => {
  stage.width(window.innerWidth);
  stage.height(window.innerHeight);
}).observe(document.body);

// ---------------------------------------------------------------------------
// Pinch-to-zoom & mouse wheel zoom
// ---------------------------------------------------------------------------

let _lastPinchDist = 0;

stage.on('touchmove', (e) => {
  e.evt.preventDefault();
  const touches = e.evt.touches;
  if (touches.length !== 2) return;
  stage.stopDrag();
  const dist = Math.hypot(
    touches[0].clientX - touches[1].clientX,
    touches[0].clientY - touches[1].clientY,
  );
  if (_lastPinchDist === 0) { _lastPinchDist = dist; return; }
  _applyZoom(
    { x: (touches[0].clientX + touches[1].clientX) / 2,
      y: (touches[0].clientY + touches[1].clientY) / 2 },
    dist / _lastPinchDist,
  );
  _lastPinchDist = dist;
});
stage.on('touchend touchcancel', () => { _lastPinchDist = 0; });

stage.on('wheel', (e) => {
  e.evt.preventDefault();
  _applyZoom(stage.getPointerPosition(), e.evt.deltaY < 0 ? 1.06 : 1 / 1.06);
});

function _applyZoom(center, factor) {
  const oldScale = stage.scaleX();
  const newScale = Math.max(0.1, Math.min(20, oldScale * factor));
  const anchorX  = (center.x - stage.x()) / oldScale;
  const anchorY  = (center.y - stage.y()) / oldScale;
  stage.scale({ x: newScale, y: newScale });
  stage.position({ x: center.x - anchorX * newScale, y: center.y - anchorY * newScale });
}

// ---------------------------------------------------------------------------
// Room rendering
// ---------------------------------------------------------------------------

function renderRooms() {
  if (_dragging) return; // never destroy groups while a drag is live
  roomsLayer.destroyChildren();
  rooms.forEach(_buildRoomGroup);
  roomsLayer.batchDraw();
}

function _buildRoomGroup(room) {
  const rw = room.width  * PPM;
  const rh = room.height * PPM;

  const group = new Konva.Group({
    id: `room-${room.id}`,
    x: room.x * PPM,
    y: room.y * PPM,
    draggable: mode === 'edit',
  });

  // Floor area
  group.add(new Konva.Rect({
    width: rw, height: rh,
    fill: '#ffffff',
    stroke: '#444444',
    strokeWidth: 1.5,
  }));

  // Room label
  group.add(new Konva.Text({
    width: rw, height: rh,
    text: room.name,
    fontSize: 12,
    fill: 'rgba(0,0,0,0.45)',
    align: 'center',
    verticalAlign: 'middle',
    letterSpacing: 0.8,
    listening: false,
  }));

  group.on('click tap', () => {
    if (mode === 'edit') {
      _dimRoom  = room;
      _dimGroup = group;
      _showDimensions(room, group.x(), group.y());
      notifyFlutter({ type: 'roomTapped', id: room.id });
    }
  });

  group.on('dragstart', () => {
    _dragging = true;
    if (mode === 'edit') {
      _dimRoom  = room;
      _dimGroup = group;
      _showDimensions(room, group.x(), group.y());
    }
  });

  group.on('dragend', () => { _dragging = false; _onRoomDragEnd(room, group); });
  roomsLayer.add(group);
}

// ---------------------------------------------------------------------------
// Room edge snapping during drag
// ---------------------------------------------------------------------------

const SNAP_THRESHOLD = 10; // screen pixels; scaled by stage zoom for layer coords

roomsLayer.on('dragmove', (e) => {
  if (mode !== 'edit') return;
  const node = e.target;
  if (!node.id().startsWith('room-')) return;
  const roomId = parseInt(node.id().replace('room-', ''), 10);
  const draggedRoom = rooms.find(r => r.id === roomId);
  if (!draggedRoom) return;

  const threshold = SNAP_THRESHOLD / stage.scaleX();
  const x = node.x(), y = node.y();
  const w = draggedRoom.width * PPM, h = draggedRoom.height * PPM;

  let bestX = null, bestY = null, dX = threshold, dY = threshold;

  rooms.forEach(r => {
    if (r.id === draggedRoom.id) return;
    const rx = r.x * PPM, ry = r.y * PPM;
    const rw = r.width * PPM, rh = r.height * PPM;

    // Four X snap candidates: left↔left, right↔right, right→left, left←right
    [[x, rx], [x + w, rx + rw], [x + w, rx], [x, rx + rw]].forEach(([a, b]) => {
      const d = Math.abs(a - b);
      if (d < dX) { dX = d; bestX = x + (b - a); }
    });

    // Four Y snap candidates
    [[y, ry], [y + h, ry + rh], [y + h, ry], [y, ry + rh]].forEach(([a, b]) => {
      const d = Math.abs(a - b);
      if (d < dY) { dY = d; bestY = y + (b - a); }
    });
  });

  if (bestX !== null) node.x(bestX);
  if (bestY !== null) node.y(bestY);

  if (_dimRoom && _dimRoom.id === draggedRoom.id) {
    _showDimensions(_dimRoom, node.x(), node.y());
  }

  // Move sensors belonging to this room so they keep their relative position.
  const newRoomX = node.x() / PPM;
  const newRoomY = node.y() / PPM;
  sensors.forEach(s => {
    if (s.room_id !== roomId || s.floor_x == null) return;
    const sg = sensorsLayer.findOne(`#sensor-${s.id}`);
    if (!sg) return;
    sg.x((newRoomX + s.floor_x) * PPM);
    sg.y((newRoomY + s.floor_y) * PPM);
  });
  sensorsLayer.batchDraw();
});

// ---------------------------------------------------------------------------
// Dimension overlay (tap-to-show in edit mode)
// ---------------------------------------------------------------------------

function _showDimensions(room, lx, ly) {
  dimensionsLayer.destroyChildren();
  const c   = '#1565C0';
  const DIM = 26;
  const EXT = 5;
  const rx  = lx;
  const ry  = ly;
  const rw  = room.width  * PPM;
  const rh  = room.height * PPM;

  // Determine which outer sides are free from adjacent rooms (use stored positions).
  let widthBelow  = true;
  let heightRight = true;
  rooms.forEach(r => {
    if (r.id === room.id) return;
    if (Math.abs(r.y * PPM - (ry + rh)) < DIM + EXT + 4) widthBelow  = false;
    if (Math.abs(r.x * PPM - (rx + rw)) < DIM + EXT + 4) heightRight = false;
  });

  const arrowCfg = {
    stroke: c, fill: c,
    strokeWidth: 1,
    pointerLength: 5, pointerWidth: 4,
    pointerAtBeginning: true,
    listening: false,
  };

  // Width dimension
  if (widthBelow) {
    const wy = ry + rh + DIM;
    dimensionsLayer.add(new Konva.Arrow({ ...arrowCfg, points: [rx, wy, rx + rw, wy] }));
    dimensionsLayer.add(new Konva.Line({ points: [rx,      ry + rh, rx,      wy + EXT], stroke: c, strokeWidth: 0.8, listening: false }));
    dimensionsLayer.add(new Konva.Line({ points: [rx + rw, ry + rh, rx + rw, wy + EXT], stroke: c, strokeWidth: 0.8, listening: false }));
    dimensionsLayer.add(new Konva.Text({
      x: rx + rw / 2 - 20, y: wy - 13, width: 40,
      text: `${room.width.toFixed(1)} m`,
      fontSize: 9, fill: c, align: 'center', listening: false,
    }));
  } else {
    // Inside the room near the bottom edge
    const wy = ry + rh - 18;
    dimensionsLayer.add(new Konva.Arrow({ ...arrowCfg, points: [rx + 4, wy, rx + rw - 4, wy] }));
    dimensionsLayer.add(new Konva.Text({
      x: rx + rw / 2 - 20, y: wy - 12, width: 40,
      text: `${room.width.toFixed(1)} m`,
      fontSize: 9, fill: c, align: 'center', listening: false,
    }));
  }

  // Height dimension
  if (heightRight) {
    const hx = rx + rw + DIM;
    dimensionsLayer.add(new Konva.Arrow({ ...arrowCfg, points: [hx, ry, hx, ry + rh] }));
    dimensionsLayer.add(new Konva.Line({ points: [rx + rw, ry,      hx + EXT, ry],      stroke: c, strokeWidth: 0.8, listening: false }));
    dimensionsLayer.add(new Konva.Line({ points: [rx + rw, ry + rh, hx + EXT, ry + rh], stroke: c, strokeWidth: 0.8, listening: false }));
    dimensionsLayer.add(new Konva.Text({
      x: hx - 10, y: ry + rh / 2,
      width: rh, align: 'center',
      text: `${room.height.toFixed(1)} m`,
      fontSize: 9, fill: c, listening: false,
      rotation: -90, offsetX: rh / 2, offsetY: 4.5,
    }));
  } else {
    // Inside the room near the right edge
    const hx = rx + rw - 18;
    dimensionsLayer.add(new Konva.Arrow({ ...arrowCfg, points: [hx, ry + 4, hx, ry + rh - 4] }));
    dimensionsLayer.add(new Konva.Text({
      x: hx - 10, y: ry + rh / 2,
      width: rh, align: 'center',
      text: `${room.height.toFixed(1)} m`,
      fontSize: 9, fill: c, listening: false,
      rotation: -90, offsetX: rh / 2, offsetY: 4.5,
    }));
  }

  dimensionsLayer.batchDraw();
}

function _clearDimensions() {
  _dimRoom  = null;
  _dimGroup = null;
  dimensionsLayer.destroyChildren();
  dimensionsLayer.batchDraw();
}

// ---------------------------------------------------------------------------
// Room drag end
// ---------------------------------------------------------------------------

function _onRoomDragEnd(room, group) {
  room.x = group.x() / PPM;
  room.y = group.y() / PPM;

  // Normalize: shift all rooms so the top-left of the bounding box is (0,0).
  const minX = Math.min(...rooms.map(r => r.x));
  const minY = Math.min(...rooms.map(r => r.y));
  if (minX !== 0 || minY !== 0) {
    rooms.forEach(r => { r.x -= minX; r.y -= minY; });
    rooms.forEach(r => {
      const g = roomsLayer.findOne(`#room-${r.id}`);
      if (g) { g.x(r.x * PPM); g.y(r.y * PPM); }
    });
  }

  // Reposition sensor groups to reflect any normalization shift.
  sensors.forEach(s => {
    if (s.floor_x == null) return;
    const r = rooms.find(r => r.id === s.room_id);
    if (!r) return;
    const sg = sensorsLayer.findOne(`#sensor-${s.id}`);
    if (!sg) return;
    sg.x((r.x + s.floor_x) * PPM);
    sg.y((r.y + s.floor_y) * PPM);
  });
  sensorsLayer.batchDraw();

  // Keep dimensions visible at the final position after normalization.
  if (_dimRoom && _dimRoom.id === room.id) {
    _showDimensions(room, group.x(), group.y());
  }

  notifyFlutter({
    type: 'roomsUpdated',
    rooms,
  });
  roomsLayer.batchDraw();
}

// ---------------------------------------------------------------------------
// Sensor rendering
// ---------------------------------------------------------------------------

function renderSensors() {
  sensorsLayer.destroyChildren();
  sensors.forEach(sensor => {
    if (sensor.room_id == null || sensor.floor_x == null) return;
    const room = rooms.find(r => r.id === sensor.room_id);
    if (!room) return;

    const absX = (room.x + sensor.floor_x) * PPM;
    const absY = (room.y + sensor.floor_y) * PPM;
    const label = sensor.name ?? sensor.sensor_id;

    const group = new Konva.Group({
      id: `sensor-${sensor.id}`,
      x: absX, y: absY,
      draggable: mode === 'edit',
    });

    group.add(new Konva.Circle({
      radius: 8,
      fill: '#1565C0',
      stroke: '#ffffff',
      strokeWidth: 2,
    }));

    // Highlight ring — shown by highlightSensor().
    group.add(new Konva.Circle({
      name: 'highlight-ring',
      radius: 14,
      stroke: '#FDD835',
      strokeWidth: 3,
      visible: false,
      listening: false,
    }));

    group.add(new Konva.Text({
      text: label,
      fontSize: 10,
      fill: '#424242',
      y: 11,
      offsetX: 30,
      width: 60,
      align: 'center',
      listening: false,
    }));

    let pressTimer = null;
    group.on('mousedown touchstart', () => {
      pressTimer = setTimeout(() => {
        notifyFlutter({ type: 'sensorTapped', id: String(sensor.id) });
        pressTimer = null;
      }, 500);
    });
    group.on('mouseup touchend touchcancel dragstart', () => {
      clearTimeout(pressTimer);
      pressTimer = null;
    });
    group.on('dragend', () => _onSensorDragEnd(sensor, group, room));
    sensorsLayer.add(group);
  });
  sensorsLayer.batchDraw();
}

function _onSensorDragEnd(sensor, group, originalRoom) {
  const newAbsX = group.x() / PPM;
  const newAbsY = group.y() / PPM;
  const target  = rooms.find(r =>
    newAbsX >= r.x && newAbsX <= r.x + r.width &&
    newAbsY >= r.y && newAbsY <= r.y + r.height,
  ) ?? originalRoom;

  notifyFlutter({
    type: 'sensorMoved',
    id: String(sensor.id),
    roomId: target.id,
    x: newAbsX - target.x,
    y: newAbsY - target.y,
  });
}

// ---------------------------------------------------------------------------
// Tag rendering (chips grouped by room)
// ---------------------------------------------------------------------------

function renderTags(tags) {
  tagsLayer.destroyChildren();

  const byRoom = {};
  tags.forEach(t => {
    if (t.roomId != null) (byRoom[t.roomId] ??= []).push(t);
  });

  Object.entries(byRoom).forEach(([roomId, roomTags]) => {
    const room = rooms.find(r => r.id === Number(roomId));
    if (!room) return;

    const chipW = 64, chipH = 22, chipGap = 4;
    const totalW = roomTags.length * chipW + (roomTags.length - 1) * chipGap;
    const cx = (room.x + room.width  / 2) * PPM;
    const cy = (room.y + room.height / 2) * PPM;

    roomTags.forEach((tag, i) => {
      const gx = cx - totalW / 2 + i * (chipW + chipGap);
      const g = new Konva.Group({ x: gx, y: cy - chipH / 2, listening: false });
      g.add(new Konva.Rect({ width: chipW, height: chipH, cornerRadius: 4, fill: tag.color || '#546E7A' }));
      g.add(new Konva.Text({
        width: chipW, height: chipH,
        text: tag.name,
        fontSize: 10, fill: '#ffffff',
        align: 'center', verticalAlign: 'middle',
      }));
      tagsLayer.add(g);
    });
  });
  tagsLayer.batchDraw();
}

// ---------------------------------------------------------------------------
// Fit stage to show all rooms
// ---------------------------------------------------------------------------

function _fitToRooms() {
  if (rooms.length === 0) return;
  const maxX = Math.max(...rooms.map(r => r.x + r.width));
  const maxY = Math.max(...rooms.map(r => r.y + r.height));
  const pad   = 60; // px padding
  const scale = Math.min(
    (stage.width()  - pad * 2) / (maxX * PPM),
    (stage.height() - pad * 2) / (maxY * PPM),
    2,
  );
  stage.scale({ x: scale, y: scale });
  stage.position({
    x: (stage.width()  - maxX * PPM * scale) / 2,
    y: (stage.height() - maxY * PPM * scale) / 2,
  });
}

// Dismiss dimensions when tapping the stage background.
stage.on('click tap', (e) => {
  if (e.target === stage) {
    _clearDimensions();
    notifyFlutter({ type: 'selectionCleared' });
  }
});

// ---------------------------------------------------------------------------
// Flutter → JS bridge
// ---------------------------------------------------------------------------

function notifyFlutter(msg) {
  if (window.FlutterBridge) FlutterBridge.postMessage(JSON.stringify(msg));
}

// ---------------------------------------------------------------------------
// Public API — called from Flutter via runJavaScript()
// ---------------------------------------------------------------------------

window.companion = {

  loadFloorPlan(roomsData) {
    rooms = roomsData;
    renderRooms();
    renderSensors();
    if (!_fittedOnce && rooms.length > 0) {
      _fitToRooms();
      _fittedOnce = true;
    }
    _clearDimensions();
  },

  loadSensors(sensorsData) {
    sensors = sensorsData;
    renderSensors();
  },

  updateTags(tags) {
    renderTags(tags);
  },

  updateCloud(particles) {
    particlesLayer.destroyChildren();
    particles.forEach(({ x, y, weight }) => {
      particlesLayer.add(new Konva.Circle({
        x: x * PPM, y: y * PPM,
        radius: 2,
        fill: `rgba(255,152,0,${Math.max(0, Math.min(1, weight))})`,
        listening: false,
      }));
    });
    particlesLayer.batchDraw();
  },

  setMode(newMode) {
    mode = newMode;
    const edit = newMode === 'edit';
    roomsLayer.find('Group').forEach(g => g.draggable(edit));
    sensorsLayer.find('Group').forEach(g => g.draggable(edit));
    tagsLayer.visible(!edit);
    particlesLayer.visible(!edit);
    _clearDimensions();
    stage.batchDraw();
  },

  highlightSensor(id) {
    sensorsLayer.find('.highlight-ring').forEach(r => r.visible(false));
    if (id) {
      const group = sensorsLayer.findOne(`#sensor-${id}`);
      if (group) {
        group.findOne('.highlight-ring')?.visible(true);
        const s = stage.scaleX();
        stage.position({
          x: stage.width()  / 2 - group.x() * s,
          y: stage.height() / 2 - group.y() * s,
        });
      }
    }
    sensorsLayer.batchDraw();
  },

  addRoom() {
    const s  = stage.scaleX();
    const cx = (stage.width()  / 2 - stage.x()) / s / PPM;
    const cy = (stage.height() / 2 - stage.y()) / s / PPM;
    notifyFlutter({ type: 'roomAdded', x: cx, y: cy });
  },

  fitToRooms() {
    _fitToRooms();
  },

  getPositionAtCenter() {
    const s  = stage.scaleX();
    const cx = (stage.width()  / 2 - stage.x()) / s / PPM;
    const cy = (stage.height() / 2 - stage.y()) / s / PPM;
    let result = { type: 'positionAtCenter', roomId: null };
    for (const room of rooms) {
      if (cx >= room.x && cx <= room.x + room.width &&
          cy >= room.y && cy <= room.y + room.height) {
        result = {
          type: 'positionAtCenter',
          roomId: room.id,
          x: cx - room.x,
          y: cy - room.y,
        };
        break;
      }
    }
    FlutterBridge.postMessage(JSON.stringify(result));
  },
};