import React, { useRef, useState } from 'react';
import { useFrame } from '@react-three/fiber';
import { Text, Html } from '@react-three/drei';
import * as THREE from 'three';

// ── Isometric grid helper: convert grid coords → world position ──
// Isometric: x = (col - row) * tileW/2, z = (col + row) * tileH/2
const TILE_W = 1.0;
const TILE_H = 0.5;

export function gridToWorld(row, col) {
  return [
    (col - row) * (TILE_W / 2),
    0,
    (col + row) * (TILE_H / 2),
  ];
}

// ── World pos to grid (inverse) ──────────────────────────────────
export function worldToGrid(x, z) {
  const col = (x / (TILE_W / 2) + z / (TILE_H / 2)) / 2;
  const row = (z / (TILE_H / 2) - x / (TILE_W / 2)) / 2;
  return { row: Math.round(row), col: Math.round(col) };
}

// ── Activity → glow color ────────────────────────────────────────
const ACTIVITY_COLORS = {
  idle: '#44cc44',
  thinking: '#ffcc00',
  working: '#4488ff',
  blocked: '#ff4444',
  offline: '#666666',
};

const LERP_SPEED = 0.08;

export default function AgentSprite({ agent, hovered, onHover }) {
  const meshRef = useRef();
  const glowRef = useRef();
  const [targetPos, setTargetPos] = useState(null);

  // Initialize position
  if (!targetPos && agent.position) {
    setTargetPos(gridToWorld(agent.position.row, agent.position.col));
  } else if (agent.targetPosition) {
    setTargetPos(gridToWorld(agent.targetPosition.row, agent.targetPosition.col));
  }

  useFrame((state, delta) => {
    if (!meshRef.current || !agent) return;

    // Calculate target world position
    const tgt = agent.targetPosition || agent.position;
    if (!tgt) return;

    const [tx, , tz] = gridToWorld(tgt.row, tgt.col);

    // Smooth lerp toward target
    meshRef.current.position.x += (tx - meshRef.current.position.x) * LERP_SPEED;
    meshRef.current.position.z += (tz - meshRef.current.position.z) * LERP_SPEED;

    // If close enough, snap to target
    if (
      Math.abs(tx - meshRef.current.position.x) < 0.01 &&
      Math.abs(tz - meshRef.current.position.z) < 0.01
    ) {
      meshRef.current.position.x = tx;
      meshRef.current.position.z = tz;
    }

    // Floating bob
    const bob = Math.sin(state.clock.elapsedTime * 2 + agent.position?.row || 0) * 0.05;
    meshRef.current.position.y = 0.15 + bob;

    // Glow pulse based on activity
    if (glowRef.current) {
      const pulse = Math.sin(state.clock.elapsedTime * 3) * 0.5 + 0.5;
      glowRef.current.material.opacity = agent.activity === 'working' ? 0.3 + pulse * 0.4 :
        agent.activity === 'thinking' ? 0.2 + pulse * 0.3 :
        agent.activity === 'offline' ? 0 :
        0.15;
    }
  });

  if (!agent) return null;

  const color = agent.activity === 'offline' ? '#666666' : agent.color;
  const glowColor = ACTIVITY_COLORS[agent.activity] || '#44cc44';

  return (
    <group>
      {/* Agent body — isometric cube */}
      <mesh
        ref={meshRef}
        position={targetPos || [0, 0.15, 0]}
        onPointerEnter={(e) => {
          e.stopPropagation();
          onHover(agent.id, true);
        }}
        onPointerLeave={(e) => {
          e.stopPropagation();
          onHover(agent.id, false);
        }}
        castShadow
      >
        <boxGeometry args={[0.4, 0.5, 0.3]} />
        <meshStandardMaterial
          color={color}
          emissive={color}
          emissiveIntensity={agent.activity === 'offline' ? 0 : 0.3}
          roughness={0.6}
          metalness={0.1}
        />
      </mesh>

      {/* Glow ring below agent */}
      <mesh
        ref={glowRef}
        position={
          targetPos
            ? [targetPos[0], 0.02, targetPos[2]]
            : [0, 0.02, 0]
        }
        rotation={[-Math.PI / 2, 0, 0]}
      >
        <ringGeometry args={[0.25, 0.35, 32]} />
        <meshBasicMaterial
          color={glowColor}
          transparent
          opacity={0.2}
          side={THREE.DoubleSide}
        />
      </mesh>

      {/* Agent name label */}
      <Text
        position={
          targetPos
            ? [targetPos[0], 0.7, targetPos[2]]
            : [0, 0.7, 0]
        }
        fontSize={0.15}
        color={agent.activity === 'offline' ? '#888888' : '#ffffff'}
        anchorX="center"
        anchorY="middle"
        outlineWidth={0.01}
        outlineColor="#000000"
      >
        {agent.name}
      </Text>

      {/* Hover tooltip */}
      {hovered && (
        <Html
          position={
            targetPos
              ? [targetPos[0], 0.9, targetPos[2]]
              : [0, 0.9, 0]
          }
          center
          distanceFactor={15}
          style={{ pointerEvents: 'none' }}
        >
          <div style={{
            background: 'rgba(20,20,40,0.95)',
            color: '#eee',
            padding: '8px 12px',
            borderRadius: '6px',
            fontSize: '12px',
            whiteSpace: 'nowrap',
            border: '1px solid rgba(255,255,255,0.15)',
            backdropFilter: 'blur(8px)',
          }}>
            <div style={{ fontWeight: 'bold', color: agent.color, marginBottom: 4 }}>
              {agent.name}
            </div>
            <div style={{ opacity: 0.8 }}>
              Status: <span style={{ color: glowColor }}>{agent.activity}</span>
            </div>
            {agent.currentTask && (
              <div style={{ opacity: 0.7, marginTop: 2 }}>
                {agent.currentTask}
              </div>
            )}
          </div>
        </Html>
      )}
    </group>
  );
}