'use client';

import { useState, useEffect, useRef, useCallback } from 'react';
import { CheckCircle2, Circle, ArrowRight, Loader2 } from 'lucide-react';

interface DiscoveredTool {
  name: string;
  method: string;
  description: string;
  paramCount: number;
  enabled: boolean;
}

interface AnalysisStreamProps {
  /** The analysis ID or spec input to stream */
  analysisInput: { type: 'url' | 'raw'; value: string };
  /** Called when analysis completes with selected tools */
  onComplete: (tools: DiscoveredTool[]) => void;
  /** Called if user clicks Continue */
  onContinue: (tools: DiscoveredTool[]) => void;
}

const METHOD_COLORS: Record<string, string> = {
  GET: 'bg-emerald-500/20 text-emerald-400 border-emerald-500/30',
  POST: 'bg-blue-500/20 text-blue-400 border-blue-500/30',
  PUT: 'bg-amber-500/20 text-amber-400 border-amber-500/30',
  PATCH: 'bg-orange-500/20 text-orange-400 border-orange-500/30',
  DELETE: 'bg-red-500/20 text-red-400 border-red-500/30',
};

export function AnalysisStream({
  analysisInput,
  onComplete,
  onContinue,
}: AnalysisStreamProps) {
  const [tools, setTools] = useState<DiscoveredTool[]>([]);
  const [progress, setProgress] = useState(0);
  const [step, setStep] = useState('Initializing...');
  const [done, setDone] = useState(false);
  const [error, setError] = useState<string | null>(null);
  const eventSourceRef = useRef<EventSource | null>(null);
  const containerRef = useRef<HTMLDivElement>(null);

  useEffect(() => {
    const params = new URLSearchParams();
    params.set('type', analysisInput.type);
    params.set('value', analysisInput.value);

    const es = new EventSource(`/api/analyze?${params.toString()}`);
    eventSourceRef.current = es;

    es.addEventListener('progress', (e) => {
      try {
        const data = JSON.parse(e.data);
        setProgress(data.percent || 0);
        setStep(data.step || '');
      } catch {}
    });

    es.addEventListener('tool_found', (e) => {
      try {
        const data = JSON.parse(e.data);
        const tool: DiscoveredTool = {
          name: data.name || 'Unknown',
          method: data.method || 'GET',
          description: data.description || '',
          paramCount: data.paramCount || Object.keys(data.inputSchema?.properties || {}).length || 0,
          enabled: true,
        };
        setTools((prev) => [...prev, tool]);
      } catch {}
    });

    es.addEventListener('complete', (e) => {
      try {
        const data = JSON.parse(e.data);
        setProgress(100);
        setStep('Analysis complete');
        setDone(true);

        // If complete event includes all tools, sync them
        if (data.tools && Array.isArray(data.tools)) {
          const allTools: DiscoveredTool[] = data.tools.map((t: any) => ({
            name: t.name || 'Unknown',
            method: t.method || 'GET',
            description: t.description || '',
            paramCount: t.paramCount || Object.keys(t.inputSchema?.properties || {}).length || 0,
            enabled: true,
          }));
          setTools(allTools);
          onComplete(allTools);
        }
      } catch {}
      es.close();
    });

    es.addEventListener('error', (e) => {
      try {
        const data = JSON.parse((e as any).data || '{}');
        setError(data.message || 'Analysis failed');
      } catch {
        setError('Connection lost. Analysis may have failed.');
      }
      es.close();
    });

    es.onerror = () => {
      if (!done) {
        setError('Connection lost');
        es.close();
      }
    };

    return () => {
      es.close();
    };
  }, [analysisInput, done, onComplete]);

  // Auto-scroll as tools appear
  useEffect(() => {
    if (containerRef.current) {
      containerRef.current.scrollTop = containerRef.current.scrollHeight;
    }
  }, [tools]);

  const toggleTool = useCallback((index: number) => {
    setTools((prev) =>
      prev.map((t, i) => (i === index ? { ...t, enabled: !t.enabled } : t)),
    );
  }, []);

  const enabledCount = tools.filter((t) => t.enabled).length;

  return (
    <div className="w-full space-y-6">
      {/* Progress bar */}
      <div className="space-y-2">
        <div className="flex items-center justify-between text-sm">
          <span className="text-gray-400">{step}</span>
          <span className="text-gray-500 font-mono">{Math.round(progress)}%</span>
        </div>
        <div className="w-full h-2 bg-gray-800 rounded-full overflow-hidden">
          <div
            className="h-full bg-gradient-to-r from-indigo-600 to-indigo-400 rounded-full
                       transition-all duration-500 ease-out"
            style={{ width: `${progress}%` }}
          />
        </div>
      </div>

      {/* Error state */}
      {error && (
        <div className="p-4 rounded-xl bg-red-500/10 border border-red-500/20 text-red-400 text-sm">
          {error}
        </div>
      )}

      {/* Tool list */}
      <div
        ref={containerRef}
        className="space-y-2 max-h-[400px] overflow-y-auto pr-1"
        style={{ scrollbarWidth: 'thin', scrollbarColor: '#374151 transparent' }}
      >
        {tools.map((tool, i) => (
          <div
            key={`${tool.name}-${i}`}
            className="flex items-center gap-3 p-3 rounded-lg bg-gray-800/50 border border-gray-800
                       animate-in slide-in-from-bottom-2 duration-300"
            style={{ animationDelay: `${i * 50}ms`, animationFillMode: 'both' }}
          >
            {/* Checkbox */}
            <button
              onClick={() => toggleTool(i)}
              className="flex-shrink-0"
            >
              {tool.enabled ? (
                <CheckCircle2 className="h-5 w-5 text-indigo-400" />
              ) : (
                <Circle className="h-5 w-5 text-gray-600" />
              )}
            </button>

            {/* Method badge */}
            <span
              className={`
                flex-shrink-0 px-2 py-0.5 rounded text-xs font-mono font-bold border
                ${METHOD_COLORS[tool.method] || METHOD_COLORS.GET}
              `}
            >
              {tool.method}
            </span>

            {/* Tool info */}
            <div className="flex-1 min-w-0">
              <span className="text-sm font-medium text-gray-200">{tool.name}</span>
              <p className="text-xs text-gray-500 truncate">{tool.description}</p>
            </div>

            {/* Param count */}
            <span className="flex-shrink-0 text-xs text-gray-600 font-mono">
              {tool.paramCount}p
            </span>
          </div>
        ))}

        {/* Loading indicator while streaming */}
        {!done && !error && (
          <div className="flex items-center gap-2 p-3 text-gray-500 text-sm">
            <Loader2 className="h-4 w-4 animate-spin" />
            Discovering tools...
          </div>
        )}
      </div>

      {/* Summary + Continue */}
      {done && tools.length > 0 && (
        <div className="flex items-center justify-between pt-4 border-t border-gray-800">
          <span className="text-sm text-gray-400">
            {enabledCount} of {tools.length} tools selected
          </span>
          <button
            onClick={() => onContinue(tools.filter((t) => t.enabled))}
            className="inline-flex items-center gap-2 px-6 py-2.5 rounded-lg
                       font-medium text-sm bg-indigo-600 text-white
                       hover:bg-indigo-500 transition-colors
                       shadow-lg shadow-indigo-600/20"
          >
            Continue to Editor
            <ArrowRight className="h-4 w-4" />
          </button>
        </div>
      )}
    </div>
  );
}