import React, { useMemo } from 'react';

export default function OptionsPanel({ snapshot, service, onSnapshot }) {
  if (!snapshot) return null;

  const apply = (snap) => onSnapshot(snap);

  return (
    <div>
      <TemplatePicker
        groups={snapshot.templateOptions}
        onPick={(tpl) => apply(service.selectTemplate(tpl.id))}
      />

      <div className="section">
        <h3>Layer options ({snapshot.layerOptions.length})</h3>
        {snapshot.layerOptions.length === 0 && (
          <div style={{ color: '#94a3b8', fontSize: 12, padding: 8, background: '#1e293b', borderRadius: 4 }}>
            {snapshot.template
              ? `Template "${snapshot.template.name}" không có layer interactive nào (không có layer nào có form_label). Đây là template tĩnh — thử chọn template khác.`
              : 'Chưa chọn template. Pick một template phía trên để bắt đầu.'}
          </div>
        )}
        {snapshot.layerOptions.map((layer) => (
          <LayerControl
            key={layer.id}
            layer={layer}
            service={service}
            onSnapshot={apply}
            errors={snapshot.validation.errors}
          />
        ))}
      </div>
    </div>
  );
}

function TemplatePicker({ groups, onPick }) {
  if (!groups || groups.length === 0) return null;
  return (
    <>
      {groups.map((group) => (
        <div className="section" key={group.artworkId}>
          <h3>{group.label}</h3>
          <div className="template-grid">
            {group.optionValues.map((tpl) => (
              <div
                key={tpl.id}
                className={'template-tile' + (tpl.active ? ' active' : '')}
                onClick={() => onPick(tpl)}
              >
                {tpl.thumbnail && <img src={tpl.thumbnail} alt={tpl.name} />}
                <div className="name">{tpl.name}</div>
              </div>
            ))}
          </div>
        </div>
      ))}
    </>
  );
}

function LayerControl({ layer, service, onSnapshot, errors }) {
  const error = errors.find((e) => e.type === 'layer' && e.layerId === layer.id);

  return (
    <div className="layer-control">
      <div className="label">
        <span>
          {layer.form_label || layer.name || layer.id}
          {layer.required && <span className="required">*</span>}
        </span>
        <span className="badge">{layer.input_type}</span>
      </div>

      {layer.form_visibility && (
        <div className="checkbox-row">
          <input
            id={`vis-${layer.id}`}
            type="checkbox"
            checked={layer.form_visibility_value !== false}
            onChange={(e) =>
              onSnapshot(service.changeLayerVisibility(layer, e.target.checked))
            }
          />
          <label htmlFor={`vis-${layer.id}`} style={{ fontSize: 12 }}>
            Show layer
          </label>
        </div>
      )}

      <ControlBody layer={layer} service={service} onSnapshot={onSnapshot} />

      {error && <div className="error-box">{error.message}</div>}
    </div>
  );
}

function ControlBody({ layer, service, onSnapshot }) {
  switch (layer.input_type) {
    case 'text':
      return <TextControl layer={layer} service={service} onSnapshot={onSnapshot} />;
    case 'photo':
      return <PhotoControl layer={layer} service={service} onSnapshot={onSnapshot} />;
    case 'option':
    case 'clipart':
      return <OptionGrid layer={layer} service={service} onSnapshot={onSnapshot} />;
    case 'grouped_clipart':
      return <GroupedClipartControl layer={layer} service={service} onSnapshot={onSnapshot} />;
    default:
      return (
        <div style={{ fontSize: 12, color: '#64748b' }}>
          Unsupported input_type: {layer.input_type}
        </div>
      );
  }
}

function TextControl({ layer, service, onSnapshot }) {
  return (
    <input
      type="text"
      value={layer.value || ''}
      maxLength={layer.max_length || undefined}
      placeholder={layer.text || ''}
      onChange={(e) => onSnapshot(service.changeInputValue(layer, e.target.value))}
    />
  );
}

function PhotoControl({ layer, service, onSnapshot }) {
  const onPick = (e) => {
    const file = e.target.files?.[0];
    if (!file) return;
    const url = URL.createObjectURL(file);
    onSnapshot(service.changeUploadValue(layer, url, { file }));
  };
  return (
    <div>
      {layer.show_value && (
        <img
          src={layer.show_value}
          alt=""
          style={{
            maxWidth: '100%',
            maxHeight: 100,
            border: '1px solid #334155',
            borderRadius: 4,
            marginBottom: 6,
          }}
        />
      )}
      <input type="file" accept="image/*" onChange={onPick} style={{ fontSize: 12 }} />
    </div>
  );
}

function OptionGrid({ layer, service, onSnapshot }) {
  const items = layer.option_items || [];
  if (items.length === 0) {
    return <div style={{ fontSize: 12, color: '#64748b' }}>(no items)</div>;
  }
  return (
    <div className="option-grid">
      {items.map((item) => (
        <div
          key={item.id}
          className={'option-tile' + (item.active ? ' active' : '')}
          onClick={() => onSnapshot(service.changeLayerOptionValue(item, layer))}
          title={item.name}
        >
          {item.url || item.thumbnail ? (
            <img src={item.thumbnail || item.url} alt={item.name} />
          ) : (
            <span className="label-text">{item.name}</span>
          )}
        </div>
      ))}
    </div>
  );
}

function GroupedClipartControl({ layer, service, onSnapshot }) {
  const groups = layer.option_items || [];
  const activeGroup = useMemo(
    () => groups.find((g) => g.active) || groups[0] || null,
    [groups]
  );

  if (!groups.length) {
    return <div style={{ fontSize: 12, color: '#64748b' }}>(no groups)</div>;
  }

  return (
    <div>
      <div className="group-tabs">
        {groups.map((group) => (
          <div
            key={group.id}
            className={'group-tab' + (group.active ? ' active' : '')}
            onClick={() => onSnapshot(service.changeOptionGroupClipartValue(group, layer))}
            title={group.name}
          >
            {group.thumbnail ? (
              <img src={group.thumbnail} alt={group.name} />
            ) : (
              <span className="name">{group.name}</span>
            )}
          </div>
        ))}
      </div>

      {activeGroup && (
        <div className="option-grid">
          {(activeGroup.options || []).map((item) => (
            <div
              key={item.id}
              className={'option-tile' + (item.active ? ' active' : '')}
              onClick={() =>
                onSnapshot(service.changeLayerOptionValue(item, activeGroup, layer))
              }
              title={item.name}
            >
              {item.url || item.thumbnail ? (
                <img src={item.thumbnail || item.url} alt={item.name} />
              ) : (
                <span className="label-text">{item.name}</span>
              )}
            </div>
          ))}
        </div>
      )}
    </div>
  );
}