'use client';

import { useRef } from 'react';
import { trackShareCardGenerated } from '@/lib/analytics';

interface ShareCardProps {
  sport: 'NBA' | 'MLB' | 'WNBA';
  player: string;
  stat: string;
  line: number;
  direction: 'over' | 'under';
  grade: string;
  projection?: number;
  sampleSize?: number;
}

const SPORT_COLOR: Record<ShareCardProps['sport'], string> = {
  NBA: '#E94B3C',
  MLB: '#1E90FF',
  WNBA: '#FFB347',
};

function gradeColor(grade: string): string {
  const g = (grade || '').trim().toUpperCase().charAt(0);
  if (g === 'A') return '#00C896';
  if (g === 'B') return '#4A9EFF';
  if (g === 'C') return '#FFB347';
  return '#FF6B6B';
}

/**
 * Renders a 1200x630 OG-shaped share image into a hidden canvas, then
 * provides Download + Copy actions. Intentionally hides the analysis —
 * shares the GRADE only, which is what drives traffic back to the site.
 */
export function useShareCard(props: ShareCardProps) {
  const canvasRef = useRef<HTMLCanvasElement | null>(null);

  const ensureCanvas = (): HTMLCanvasElement => {
    if (canvasRef.current) return canvasRef.current;
    const c = document.createElement('canvas');
    c.width = 1200;
    c.height = 630;
    canvasRef.current = c;
    return c;
  };

  const renderToCanvas = async (): Promise<HTMLCanvasElement> => {
    const c = ensureCanvas();
    const ctx = c.getContext('2d');
    if (!ctx) throw new Error('No 2D context.');

    // Background — obsidian with diagonal accent
    ctx.fillStyle = '#0A0A0F';
    ctx.fillRect(0, 0, c.width, c.height);

    // Diagonal gradient overlay
    const g = ctx.createLinearGradient(0, 0, c.width, c.height);
    g.addColorStop(0, 'rgba(26,74,58,0.20)');
    g.addColorStop(1, 'rgba(0,200,150,0.02)');
    ctx.fillStyle = g;
    ctx.fillRect(0, 0, c.width, c.height);

    // VYNDR wordmark top-left
    ctx.fillStyle = '#F0F0F5';
    ctx.font = '800 38px "JetBrains Mono", "SF Mono", ui-monospace, monospace';
    ctx.fillText('VYND', 64, 96);
    ctx.fillStyle = '#00D4A0';
    ctx.fillText('R', 64 + ctx.measureText('VYND').width, 96);

    // Sport badge
    const sportColor = SPORT_COLOR[props.sport];
    ctx.font = '700 16px "JetBrains Mono", monospace';
    ctx.fillStyle = sportColor;
    ctx.fillText(props.sport, 64, 220);

    // Player name (large)
    ctx.fillStyle = '#F0F0F5';
    ctx.font = '700 72px "Instrument Sans", system-ui, sans-serif';
    wrapText(ctx, props.player, 64, 300, 780, 80);

    // Prop line (mono)
    ctx.fillStyle = '#8A8A9A';
    ctx.font = '500 28px "JetBrains Mono", monospace';
    const cap = (s: string) => s.charAt(0).toUpperCase() + s.slice(1);
    ctx.fillText(
      `${cap(props.direction)} ${props.line} ${props.stat.replace(/_/g, ' ')}`,
      64,
      420,
    );

    // Grade letter (huge, colored)
    const gc = gradeColor(props.grade);
    ctx.fillStyle = gc;
    ctx.font = '800 240px "JetBrains Mono", monospace';
    ctx.textAlign = 'right';
    ctx.fillText(props.grade || '—', c.width - 64, 380);

    // Glow ring behind the grade
    ctx.shadowColor = gc;
    ctx.shadowBlur = 60;
    ctx.fillText(props.grade || '—', c.width - 64, 380);
    ctx.shadowBlur = 0;

    // Projection (small, beneath player line)
    if (props.projection != null) {
      ctx.textAlign = 'left';
      ctx.fillStyle = '#5A5A6A';
      ctx.font = '500 22px "JetBrains Mono", monospace';
      ctx.fillText(`Projection ${props.projection.toFixed(1)}`, 64, 470);
    }

    // Footer — watermark
    ctx.textAlign = 'left';
    ctx.fillStyle = '#5A5A6A';
    ctx.font = '500 18px "JetBrains Mono", monospace';
    ctx.fillText('vyndr.app', 64, 580);
    ctx.textAlign = 'right';
    ctx.fillStyle = '#5A5A6A';
    ctx.fillText('Built in Detroit.', c.width - 64, 580);

    return c;
  };

  const download = async () => {
    const c = await renderToCanvas();
    c.toBlob((blob) => {
      if (!blob) return;
      const url = URL.createObjectURL(blob);
      const a = document.createElement('a');
      a.href = url;
      a.download = `vyndr-${props.player.replace(/\W+/g, '-')}-${props.grade}.png`.toLowerCase();
      document.body.appendChild(a);
      a.click();
      a.remove();
      URL.revokeObjectURL(url);
      trackShareCardGenerated({ sport: props.sport, grade: props.grade });
    }, 'image/png');
  };

  const copyToClipboard = async (): Promise<boolean> => {
    if (typeof ClipboardItem === 'undefined' || !navigator.clipboard?.write) return false;
    const c = await renderToCanvas();
    return new Promise<boolean>((resolve) => {
      c.toBlob(async (blob) => {
        if (!blob) return resolve(false);
        try {
          await navigator.clipboard.write([new ClipboardItem({ 'image/png': blob })]);
          trackShareCardGenerated({ sport: props.sport, grade: props.grade });
          resolve(true);
        } catch {
          resolve(false);
        }
      }, 'image/png');
    });
  };

  return { download, copyToClipboard };
}

function wrapText(
  ctx: CanvasRenderingContext2D,
  text: string,
  x: number,
  y: number,
  maxWidth: number,
  lineHeight: number,
) {
  const words = text.split(' ');
  let line = '';
  for (const word of words) {
    const test = line ? `${line} ${word}` : word;
    const m = ctx.measureText(test);
    if (m.width > maxWidth && line) {
      ctx.fillText(line, x, y);
      line = word;
      y += lineHeight;
    } else {
      line = test;
    }
  }
  if (line) ctx.fillText(line, x, y);
}