import { useMemo } from 'react';
import { useWindowDimensions, View } from 'react-native';
import Svg, { Circle, Path, G } from 'react-native-svg';
import { useColors } from '../../lib/theme';

const TILE = 80;
const OPACITY = 0.07;

type Symbol = 'star' | 'heart' | 'check' | 'dot' | 'cloud' | 'wave' | 'diamond';

const SEQUENCE: Symbol[] = [
  'star', 'dot', 'heart', 'wave', 'check', 'dot', 'cloud',
  'diamond', 'dot', 'star', 'check', 'heart', 'dot', 'wave',
];

function SymbolShape({ type, color }: { type: Symbol; color: string }) {
  switch (type) {
    case 'star':
      return (
        <Path
          d="M10 2 L11.8 7.6 L18 7.6 L13 11.2 L14.8 16.8 L10 13.2 L5.2 16.8 L7 11.2 L2 7.6 L8.2 7.6 Z"
          fill={color}
          opacity={OPACITY}
        />
      );
    case 'heart':
      return (
        <Path
          d="M10 15 C10 15 3 10 3 6 C3 3.8 4.8 2 7 2 C8.3 2 9.5 2.7 10 3.7 C10.5 2.7 11.7 2 13 2 C15.2 2 17 3.8 17 6 C17 10 10 15 10 15 Z"
          fill={color}
          opacity={OPACITY}
        />
      );
    case 'check':
      return (
        <Path
          d="M3 9 L7 13 L17 4"
          stroke={color}
          strokeWidth={2}
          strokeLinecap="round"
          strokeLinejoin="round"
          fill="none"
          opacity={OPACITY}
        />
      );
    case 'dot':
      return <Circle cx="10" cy="10" r="3.5" fill={color} opacity={OPACITY} />;
    case 'cloud':
      return (
        <Path
          d="M5 12 C3.3 12 2 10.7 2 9 C2 7.4 3.2 6.1 4.7 6 C5 4.3 6.5 3 8.3 3 C9.8 3 11.1 3.9 11.7 5.2 C12 5.1 12.3 5 12.7 5 C14.5 5 16 6.5 16 8.3 C16 10.3 14.3 12 12.3 12 Z"
          fill={color}
          opacity={OPACITY}
        />
      );
    case 'wave':
      return (
        <Path
          d="M2 10 Q5 7 8 10 Q11 13 14 10 Q17 7 20 10"
          stroke={color}
          strokeWidth={1.5}
          strokeLinecap="round"
          fill="none"
          opacity={OPACITY}
        />
      );
    case 'diamond':
      return (
        <Path
          d="M10 2 L18 10 L10 18 L2 10 Z"
          fill={color}
          opacity={OPACITY}
        />
      );
  }
}

export function DmChatBackground() {
  const { width, height } = useWindowDimensions();
  const colors = useColors();

  const patternColor = colors.text;

  const cols = Math.ceil(width / TILE) + 1;
  const rows = Math.ceil(height / TILE) + 1;

  const symbols = useMemo(() => {
    const items: { x: number; y: number; type: Symbol; rotate: number }[] = [];
    let seq = 0;
    for (let r = 0; r < rows; r++) {
      for (let c = 0; c < cols; c++) {
        const offsetX = r % 2 === 0 ? 0 : TILE / 2;
        items.push({
          x: c * TILE + offsetX + TILE / 2,
          y: r * TILE + TILE / 2,
          type: SEQUENCE[seq % SEQUENCE.length],
          rotate: [0, 15, -10, 30, -20, 5, -15][seq % 7],
        });
        seq++;
      }
    }
    return items;
  }, [cols, rows]);

  return (
    <View style={{ position: 'absolute', top: 0, left: 0, right: 0, bottom: 0 }} pointerEvents="none">
      <Svg width={width} height={height}>
        {symbols.map((s, i) => (
          <G
            key={i}
            transform={`translate(${s.x - 10}, ${s.y - 10}) rotate(${s.rotate}, 10, 10)`}
          >
            <SymbolShape type={s.type} color={patternColor} />
          </G>
        ))}
      </Svg>
    </View>
  );
}