import { useState } from 'react';
import { ChevronDown, ChevronRight, Loader2, User, Sparkles } from 'lucide-react';

export default function NeonModelSelector({ models, selected, onSelectionChange, loading }) {
  const [expandedModel, setExpandedModel] = useState(null);

  const isModelSelected = (modelId, personaName) =>
    selected.some(s => s.model_id === modelId && s.persona_name === personaName);

  const togglePersona = (model, persona) => {
    const key = { model_id: model.model_id, persona_name: persona.persona_name, system_prompt: persona.system_prompt || '' };
    if (isModelSelected(model.model_id, persona.persona_name)) {
      onSelectionChange(selected.filter(s => !(s.model_id === model.model_id && s.persona_name === persona.persona_name)));
    } else {
      onSelectionChange([...selected, key]);
    }
  };

  const shortName = (name) => name.split('/').pop();

  if (loading) {
    return (
      <div className="selector-section">
        <h3 className="selector-title"><Sparkles size={16} className="selector-title-icon" aria-hidden /> Neon.ai Models</h3>
        <div className="selector-loading"><Loader2 size={20} className="spin" /> Loading models...</div>
      </div>
    );
  }

  return (
    <div className="selector-section">
      <h3 className="selector-title"><Sparkles size={16} className="selector-title-icon" aria-hidden /> Neon.ai Models</h3>
      <p className="selector-hint">Select model + persona for comparison</p>
      <div className="neon-model-list">
        {[...models].sort((a, b) => shortName(a.name).localeCompare(shortName(b.name))).map(model => {
          const isExpanded = expandedModel === model.model_id;
          const activePersonas = model.personas.filter(p => p.enabled !== false);
          const selectedCount = selected.filter(s => s.model_id === model.model_id).length;

          return (
            <div key={model.model_id} className="neon-model-card">
              <button
                className="neon-model-header"
                onClick={() => setExpandedModel(isExpanded ? null : model.model_id)}
              >
                <div className="neon-model-info">
                  <span className="neon-model-name">{shortName(model.name)}</span>
                  <span className="neon-model-version">v{model.version}</span>
                </div>
                <div className="neon-model-meta">
                  {selectedCount > 0 && <span className="badge badge-neon">{selectedCount}</span>}
                  {isExpanded ? <ChevronDown size={16} /> : <ChevronRight size={16} />}
                </div>
              </button>
              {isExpanded && (
                <div className="neon-persona-list">
                  {activePersonas.map(persona => {
                    const checked = isModelSelected(model.model_id, persona.persona_name);
                    return (
                      <label key={persona.id} className={`neon-persona-item ${checked ? 'selected' : ''}`}>
                        <input
                          type="checkbox"
                          checked={checked}
                          onChange={() => togglePersona(model, persona)}
                        />
                        <div className="persona-details">
                          <div className="persona-name">
                            <User size={12} />
                            {persona.persona_name}
                          </div>
                          {persona.system_prompt && (
                            <div className="persona-prompt-preview">
                              {persona.system_prompt.slice(0, 120)}
                              {persona.system_prompt.length > 120 ? '...' : ''}
                            </div>
                          )}
                          {!persona.system_prompt && (
                            <div className="persona-prompt-preview">No system prompt (vanilla)</div>
                          )}
                        </div>
                      </label>
                    );
                  })}
                </div>
              )}
            </div>
          );
        })}
      </div>

      <style>{`
        .selector-section {
          display: flex;
          flex-direction: column;
          gap: 8px;
        }
        .selector-title {
          display: flex;
          align-items: center;
          gap: 6px;
          font-size: 15px;
          font-weight: 700;
          color: var(--text-primary);
          text-decoration: underline;
          text-underline-offset: 3px;
          text-decoration-color: var(--border-primary);
        }
        .selector-title-icon {
          height: 16px;
          width: auto;
        }
        .selector-hint {
          font-size: 12px;
          color: var(--text-muted);
        }
        .selector-loading {
          display: flex;
          align-items: center;
          gap: 8px;
          font-size: 13px;
          color: var(--text-tertiary);
          padding: 12px 0;
        }
        .neon-model-list {
          display: flex;
          flex-direction: column;
          gap: 6px;
        }
        .neon-model-card {
          border: 1px solid var(--border-primary);
          border-radius: 8px;
          overflow: hidden;
          background: #EAE0FD;
        }
        :root[data-theme="dark"] .neon-model-card {
          background: #2D2640;
        }
        .neon-model-header {
          display: flex;
          align-items: center;
          justify-content: space-between;
          width: 100%;
          padding: 10px 12px;
          background: none;
          border: none;
          color: var(--text-primary);
          font-size: 13px;
          text-align: left;
          transition: background 0.15s;
        }
        .neon-model-header:hover {
          background: var(--card-hover);
        }
        .neon-model-info {
          display: flex;
          align-items: baseline;
          gap: 6px;
        }
        .neon-model-name {
          font-weight: 600;
        }
        .neon-model-version {
          font-size: 11px;
          color: var(--text-muted);
        }
        .neon-model-meta {
          display: flex;
          align-items: center;
          gap: 6px;
          color: var(--text-tertiary);
        }
        .neon-persona-list {
          border-top: 1px solid var(--border-muted);
          padding: 4px;
        }
        .neon-persona-item {
          display: flex;
          align-items: flex-start;
          gap: 8px;
          padding: 8px;
          border-radius: 6px;
          cursor: pointer;
          transition: background 0.15s;
        }
        .neon-persona-item:hover {
          background: var(--card-hover);
        }
        .neon-persona-item.selected {
          background: var(--card-bg);
        }
        .neon-persona-item input[type="checkbox"] {
          margin-top: 2px;
          accent-color: var(--neon-accent);
        }
        .persona-details {
          flex: 1;
          min-width: 0;
        }
        .persona-name {
          display: flex;
          align-items: center;
          gap: 4px;
          font-size: 13px;
          font-weight: 500;
          color: var(--text-primary);
        }
        .persona-prompt-preview {
          font-size: 11px;
          color: var(--text-muted);
          line-height: 1.4;
          margin-top: 2px;
          overflow: hidden;
          display: -webkit-box;
          -webkit-line-clamp: 2;
          -webkit-box-orient: vertical;
        }
      `}</style>
    </div>
  );
}