/**
 * StudioParameterList - Display and add discovered parameters as design variables
 */

import React, { useState, useEffect } from 'react';
import { Plus, Check, SlidersHorizontal, Loader2 } from 'lucide-react';
import { intakeApi } from '../../api/intake';

interface Expression {
  name: string;
  value: number | null;
  units: string | null;
  is_candidate: boolean;
  confidence: number;
}

interface StudioParameterListProps {
  draftId: string;
  onParameterAdded: () => void;
}

export const StudioParameterList: React.FC<StudioParameterListProps> = ({
  draftId,
  onParameterAdded,
}) => {
  const [expressions, setExpressions] = useState<Expression[]>([]);
  const [addedParams, setAddedParams] = useState<Set<string>>(new Set());
  const [adding, setAdding] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  
  // Load expressions from spec introspection
  useEffect(() => {
    loadExpressions();
  }, [draftId]);
  
  const loadExpressions = async () => {
    setLoading(true);
    try {
      const data = await intakeApi.getStudioDraft(draftId);
      const introspection = (data.spec as any)?.model?.introspection;
      
      if (introspection?.expressions) {
        setExpressions(introspection.expressions);
        
        // Check which are already added as DVs
        const existingDVs = new Set<string>(
          ((data.spec as any)?.design_variables || []).map((dv: any) => dv.expression_name as string)
        );
        setAddedParams(existingDVs);
      }
    } catch (err) {
      console.error('Failed to load expressions:', err);
    } finally {
      setLoading(false);
    }
  };
  
  const addAsDesignVariable = async (expressionName: string) => {
    setAdding(expressionName);
    
    try {
      await intakeApi.createDesignVariables(draftId, [expressionName]);
      setAddedParams(prev => new Set([...prev, expressionName]));
      onParameterAdded();
    } catch (err) {
      console.error('Failed to add design variable:', err);
    } finally {
      setAdding(null);
    }
  };
  
  // Sort: candidates first, then by confidence
  const sortedExpressions = [...expressions].sort((a, b) => {
    if (a.is_candidate !== b.is_candidate) {
      return b.is_candidate ? 1 : -1;
    }
    return (b.confidence || 0) - (a.confidence || 0);
  });
  
  // Show only candidates by default, with option to show all
  const [showAll, setShowAll] = useState(false);
  const displayExpressions = showAll 
    ? sortedExpressions 
    : sortedExpressions.filter(e => e.is_candidate);
  
  if (loading) {
    return (
      <div className="flex items-center justify-center py-4">
        <Loader2 className="w-5 h-5 text-primary-400 animate-spin" />
      </div>
    );
  }
  
  if (expressions.length === 0) {
    return (
      <p className="text-xs text-dark-500 italic py-2">
        No expressions found. Try running introspection.
      </p>
    );
  }
  
  const candidateCount = expressions.filter(e => e.is_candidate).length;
  
  return (
    <div className="space-y-2">
      {/* Header with toggle */}
      <div className="flex items-center justify-between text-xs text-dark-400">
        <span>{candidateCount} candidates</span>
        <button
          onClick={() => setShowAll(!showAll)}
          className="hover:text-primary-400 transition-colors"
        >
          {showAll ? 'Show candidates only' : `Show all (${expressions.length})`}
        </button>
      </div>
      
      {/* Parameter List */}
      <div className="space-y-1 max-h-48 overflow-y-auto">
        {displayExpressions.map((expr) => {
          const isAdded = addedParams.has(expr.name);
          const isAdding = adding === expr.name;
          
          return (
            <div
              key={expr.name}
              className={`flex items-center gap-2 px-2 py-1.5 rounded text-sm
                         ${isAdded ? 'bg-green-500/10' : 'bg-dark-700/50 hover:bg-dark-700'}
                         transition-colors`}
            >
              <SlidersHorizontal className="w-3.5 h-3.5 text-dark-400 flex-shrink-0" />
              <div className="flex-1 min-w-0">
                <span className={`block truncate ${isAdded ? 'text-green-400' : 'text-dark-200'}`}>
                  {expr.name}
                </span>
                {expr.value !== null && (
                  <span className="text-xs text-dark-500">
                    = {expr.value}{expr.units ? ` ${expr.units}` : ''}
                  </span>
                )}
              </div>
              
              {isAdded ? (
                <Check className="w-4 h-4 text-green-400 flex-shrink-0" />
              ) : (
                <button
                  onClick={() => addAsDesignVariable(expr.name)}
                  disabled={isAdding}
                  className="p-1 hover:bg-primary-400/20 rounded text-primary-400 transition-colors disabled:opacity-50"
                  title="Add as design variable"
                >
                  {isAdding ? (
                    <Loader2 className="w-3.5 h-3.5 animate-spin" />
                  ) : (
                    <Plus className="w-3.5 h-3.5" />
                  )}
                </button>
              )}
            </div>
          );
        })}
      </div>
      
      {displayExpressions.length === 0 && (
        <p className="text-xs text-dark-500 italic py-2">
          No candidate parameters found. Click "Show all" to see all expressions.
        </p>
      )}
    </div>
  );
};

export default StudioParameterList;