import React, { useEffect, useRef, useState, useCallback } from 'react';
import { useAssets } from '../../hooks/useAssets';
import { clickableProps } from '../../utils/a11y';
import { copyToClipboard } from '../../utils/clipboard';

/** How long the "Delete?" confirm state stays armed before auto-resetting. */
const DELETE_CONFIRM_TIMEOUT_MS = 4000;

export const AssetsPanel: React.FC = () => {
  const { assets, loading, error, loadAssets, uploadAsset, deleteAsset } = useAssets();
  const fileInputRef = useRef<HTMLInputElement>(null);
  const [isDragOver, setIsDragOver] = useState(false);
  const [copiedUrl, setCopiedUrl] = useState<string | null>(null);
  const [copyErrorUrl, setCopyErrorUrl] = useState<string | null>(null);
  const [confirmDeleteName, setConfirmDeleteName] = useState<string | null>(null);
  const deleteConfirmTimeoutRef = useRef<ReturnType<typeof setTimeout> | null>(null);

  useEffect(() => {
    return () => {
      if (deleteConfirmTimeoutRef.current) clearTimeout(deleteConfirmTimeoutRef.current);
    };
  }, []);

  const resetDeleteConfirm = useCallback(() => {
    if (deleteConfirmTimeoutRef.current) clearTimeout(deleteConfirmTimeoutRef.current);
    setConfirmDeleteName(null);
  }, []);

  const armDeleteConfirm = useCallback((name: string) => {
    setConfirmDeleteName(name);
    if (deleteConfirmTimeoutRef.current) clearTimeout(deleteConfirmTimeoutRef.current);
    deleteConfirmTimeoutRef.current = setTimeout(() => setConfirmDeleteName(null), DELETE_CONFIRM_TIMEOUT_MS);
  }, []);

  useEffect(() => {
    loadAssets();
  }, [loadAssets]);

  const handleFileSelect = useCallback(async (files: FileList | null) => {
    if (!files) return;
    for (let i = 0; i < files.length; i++) {
      await uploadAsset(files[i]);
    }
  }, [uploadAsset]);

  const handleDrop = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragOver(false);
    handleFileSelect(e.dataTransfer.files);
  }, [handleFileSelect]);

  const handleDragOver = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragOver(true);
  }, []);

  const handleDragLeave = useCallback((e: React.DragEvent) => {
    e.preventDefault();
    e.stopPropagation();
    setIsDragOver(false);
  }, []);

  const copyUrl = useCallback(async (url: string) => {
    const ok = await copyToClipboard(url);
    if (ok) {
      setCopyErrorUrl(null);
      setCopiedUrl(url);
      setTimeout(() => setCopiedUrl(null), 2000);
    } else {
      setCopiedUrl(null);
      setCopyErrorUrl(url);
      setTimeout(() => setCopyErrorUrl(null), 2500);
    }
  }, []);

  const isImage = (type: string) =>
    type.startsWith('image/') || /\.(jpg|jpeg|png|gif|svg|webp|ico)$/i.test(type);

  return (
    <div style={{ display: 'flex', flexDirection: 'column', gap: 10 }}>
      {/* Upload button */}
      <input
        ref={fileInputRef}
        type="file"
        multiple
        style={{ display: 'none' }}
        onChange={(e) => handleFileSelect(e.target.files)}
      />
      <button
        onClick={() => fileInputRef.current?.click()}
        disabled={loading}
        style={{
          width: '100%',
          padding: '8px 12px',
          fontSize: 12,
          fontWeight: 600,
          color: '#fff',
          background: loading ? 'var(--color-bg-active)' : 'var(--color-accent)',
          border: 'none',
          borderRadius: 'var(--radius-md)',
          cursor: loading ? 'not-allowed' : 'pointer',
          transition: 'all var(--transition-fast)',
        }}
      >
        {loading ? 'Uploading...' : 'Upload File'}
      </button>

      {/* Drop zone */}
      <div
        onDrop={handleDrop}
        onDragOver={handleDragOver}
        onDragLeave={handleDragLeave}
        style={{
          padding: 20,
          border: `2px dashed ${isDragOver ? 'var(--color-accent)' : 'var(--color-border)'}`,
          borderRadius: 'var(--radius-md)',
          background: isDragOver ? 'var(--color-accent-subtle)' : 'transparent',
          textAlign: 'center',
          color: isDragOver ? 'var(--color-accent)' : 'var(--color-text-dim)',
          fontSize: 11,
          transition: 'all var(--transition-fast)',
        }}
      >
        Drop files here to upload
      </div>

      {/* Error message */}
      {error && (
        <div
          style={{
            padding: '6px 10px',
            fontSize: 11,
            color: 'var(--color-danger)',
            background: 'rgba(239, 68, 68, 0.1)',
            borderRadius: 'var(--radius-sm)',
            border: '1px solid rgba(239, 68, 68, 0.2)',
          }}
        >
          {error}
        </div>
      )}

      {/* Asset grid */}
      {assets.length === 0 && !loading && (
        <div
          style={{
            textAlign: 'center',
            padding: 20,
            color: 'var(--color-text-dim)',
            fontSize: 12,
            fontStyle: 'italic',
          }}
        >
          No assets uploaded yet
        </div>
      )}

      <div
        style={{
          display: 'grid',
          gridTemplateColumns: 'repeat(2, 1fr)',
          gap: 6,
        }}
      >
        {assets.map((asset) => {
          const isConfirmingDelete = confirmDeleteName === asset.name;
          return (
          <div
            key={asset.name}
            {...clickableProps(() => {
              // While armed, clicking anywhere on the tile (other than the
              // delete control itself) counts as "click elsewhere" and
              // disarms the confirm instead of copying the URL.
              if (isConfirmingDelete) {
                resetDeleteConfirm();
                return;
              }
              copyUrl(asset.url);
            })}
            style={{
              position: 'relative',
              background: 'var(--color-bg-elevated)',
              border: '1px solid var(--color-border)',
              borderRadius: 'var(--radius-md)',
              overflow: 'visible',
              cursor: 'pointer',
              transition: 'border-color var(--transition-fast)',
            }}
            title={`Click to copy URL: ${asset.url}`}
          >
            {/* Thumbnail */}
            <div
              style={{
                width: '100%',
                aspectRatio: '1',
                display: 'flex',
                alignItems: 'center',
                justifyContent: 'center',
                background: 'var(--color-bg-base)',
                overflow: 'hidden',
                borderRadius: 'var(--radius-md) var(--radius-md) 0 0',
              }}
            >
              {isImage(asset.type) ? (
                <img
                  src={asset.url}
                  alt={asset.name}
                  style={{
                    width: '100%',
                    height: '100%',
                    objectFit: 'cover',
                  }}
                  loading="lazy"
                />
              ) : (
                <span
                  style={{
                    fontSize: 20,
                    color: 'var(--color-text-dim)',
                  }}
                >
                  &#128196;
                </span>
              )}
            </div>

            {/* Name / status */}
            <div
              style={{
                padding: '4px 6px',
                fontSize: 10,
                color: copyErrorUrl === asset.url ? 'var(--color-danger)' : 'var(--color-text-muted)',
                overflow: 'hidden',
                textOverflow: 'ellipsis',
                whiteSpace: 'nowrap',
              }}
            >
              {copyErrorUrl === asset.url ? 'Copy failed' : copiedUrl === asset.url ? 'Copied!' : asset.name}
            </div>

            {/* Delete control: idle icon, or an in-app two-step confirm */}
            {isConfirmingDelete ? (
              <div
                style={{
                  position: 'absolute',
                  top: 4,
                  right: 4,
                  display: 'flex',
                  gap: 3,
                  zIndex: 1,
                }}
              >
                <button
                  onClick={(e) => {
                    e.stopPropagation();
                    resetDeleteConfirm();
                    deleteAsset(asset.name);
                  }}
                  title="Click again to permanently delete"
                  aria-label={`Confirm delete ${asset.name}`}
                  autoFocus
                  style={{
                    padding: '2px 6px',
                    fontSize: 9,
                    fontWeight: 700,
                    color: '#fff',
                    background: 'var(--color-danger)',
                    border: 'none',
                    borderRadius: 'var(--radius-sm)',
                    cursor: 'pointer',
                    whiteSpace: 'nowrap',
                  }}
                >
                  Delete?
                </button>
                <button
                  onClick={(e) => {
                    e.stopPropagation();
                    resetDeleteConfirm();
                  }}
                  title="Cancel"
                  aria-label={`Cancel delete ${asset.name}`}
                  style={{
                    width: 18,
                    height: 18,
                    display: 'flex',
                    alignItems: 'center',
                    justifyContent: 'center',
                    fontSize: 9,
                    color: '#fff',
                    background: 'rgba(0,0,0,0.6)',
                    border: 'none',
                    borderRadius: '50%',
                    cursor: 'pointer',
                  }}
                >
                  &#10005;
                </button>
              </div>
            ) : (
              <button
                onClick={(e) => {
                  e.stopPropagation();
                  armDeleteConfirm(asset.name);
                }}
                title="Delete asset"
                aria-label={`Delete ${asset.name}`}
                style={{
                  position: 'absolute',
                  top: 4,
                  right: 4,
                  width: 20,
                  height: 20,
                  display: 'flex',
                  alignItems: 'center',
                  justifyContent: 'center',
                  fontSize: 10,
                  color: '#fff',
                  background: 'rgba(0,0,0,0.6)',
                  border: 'none',
                  borderRadius: '50%',
                  cursor: 'pointer',
                  opacity: 0.7,
                  transition: 'opacity var(--transition-fast)',
                }}
                onMouseEnter={(e) => { (e.target as HTMLElement).style.opacity = '1'; }}
                onMouseLeave={(e) => { (e.target as HTMLElement).style.opacity = '0.7'; }}
              >
                &#10005;
              </button>
            )}
          </div>
          );
        })}
      </div>

      {/* Loading indicator */}
      {loading && assets.length > 0 && (
        <div
          style={{
            textAlign: 'center',
            padding: 10,
            color: 'var(--color-text-dim)',
            fontSize: 11,
          }}
        >
          Loading...
        </div>
      )}
    </div>
  );
};