'use client';

import { useEffect, useState } from 'react';
import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
import { Button } from '@/components/ui/button';
import { Input } from '@/components/ui/input';
import { Badge } from '@/components/ui/badge';
import { Alert, AlertDescription } from '@/components/ui/alert';
import { RefreshCw, Check, X, Cpu, Search } from 'lucide-react';

interface Model {
  id: string;
  name: string;
}

export function ModelSwitcher() {
  const [models, setModels] = useState<Model[]>([]);
  const [activeModel, setActiveModelState] = useState<string | null>(null);
  const [loading, setLoading] = useState(true);
  const [switching, setSwitching] = useState<string | null>(null);
  const [filter, setFilter] = useState('');
  const [message, setMessage] = useState<{ type: 'success' | 'error'; text: string } | null>(null);

  const fetchData = async () => {
    setLoading(true);
    try {
      const response = await fetch('/api/models');
      const data = await response.json();
      setModels(data.models || []);
      setActiveModelState(data.activeModel);
    } catch (error) {
      console.error('Failed to fetch models:', error);
      setMessage({ type: 'error', text: 'Failed to load models' });
    } finally {
      setLoading(false);
    }
  };

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

  const handleSwitchModel = async (modelId: string) => {
    if (switching) return;

    setSwitching(modelId);
    setMessage(null);

    try {
      const response = await fetch('/api/models', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ modelId }),
      });

      const result = await response.json();

      if (result.success) {
        setMessage({ type: 'success', text: result.message });
        setActiveModelState(modelId);
      } else {
        setMessage({ type: 'error', text: result.message || 'Failed to switch model' });
      }
    } catch (error) {
      setMessage({ type: 'error', text: 'Failed to switch model' });
    } finally {
      setSwitching(null);
    }
  };

  const groupedModels = models.reduce((acc, model) => {
    const provider = model.id.split('/')[0];
    if (!acc[provider]) {
      acc[provider] = [];
    }
    acc[provider].push(model);
    return acc;
  }, {} as Record<string, Model[]>);

  const filteredGroups = filter
    ? Object.fromEntries(
        Object.entries(groupedModels).filter(([_, models]) =>
          models.some((m) =>
            m.name.toLowerCase().includes(filter.toLowerCase()) ||
            m.id.toLowerCase().includes(filter.toLowerCase())
          )
        )
      )
    : groupedModels;

  return (
    <div className="space-y-4">
      {/* Header */}
      <div className="flex flex-wrap gap-2 items-center justify-between">
        <div className="flex items-center gap-4">
          <Button
            onClick={fetchData}
            disabled={loading}
            variant="outline"
            className="border-zinc-700 hover:bg-zinc-800"
          >
            <RefreshCw className={`w-4 h-4 mr-2 ${loading ? 'animate-spin' : ''}`} />
            Refresh
          </Button>
          {activeModel && (
            <div className="flex items-center gap-2 px-3 py-1.5 rounded-lg bg-green-500/10 border border-green-500/20">
              <Cpu className="w-4 h-4 text-green-400" />
              <span className="text-sm text-green-400">Active: {activeModel}</span>
            </div>
          )}
        </div>
        <div className="relative min-w-[200px] max-w-md flex-1">
          <Search className="absolute left-3 top-1/2 -translate-y-1/2 w-4 h-4 text-zinc-500" />
          <Input
            placeholder="Search models..."
            value={filter}
            onChange={(e) => setFilter(e.target.value)}
            className="pl-10 bg-zinc-900/50 border-zinc-700 focus:border-orange-500"
          />
        </div>
      </div>

      {/* Message */}
      {message && (
        <Alert variant={message.type === 'error' ? 'destructive' : 'default'} className={
          message.type === 'success' ? 'bg-green-500/10 border-green-500/20 text-green-400' : ''
        }>
          {message.type === 'success' ? (
            <Check className="h-4 w-4" />
          ) : (
            <X className="h-4 w-4" />
          )}
          <AlertDescription>{message.text}</AlertDescription>
        </Alert>
      )}

      {/* Models List */}
      {loading ? (
        <div className="flex items-center justify-center h-64">
          <RefreshCw className="w-8 h-8 animate-spin text-orange-400" />
        </div>
      ) : Object.keys(filteredGroups).length === 0 ? (
        <Card className="bg-zinc-900/50 border-zinc-800">
          <CardContent className="py-12 text-center text-zinc-500">
            <Cpu className="w-12 h-12 mx-auto mb-4 opacity-50" />
            <p>{filter ? 'No models match your search' : 'No models found'}</p>
          </CardContent>
        </Card>
      ) : (
        <div className="space-y-4">
          {Object.entries(filteredGroups).map(([provider, providerModels]) => (
            <Card key={provider} className="bg-zinc-900/50 border-zinc-800">
              <CardHeader>
                <CardTitle className="capitalize text-lg">
                  {provider}
                  <Badge variant="outline" className="ml-2 border-zinc-700">
                    {providerModels.length}
                  </Badge>
                </CardTitle>
              </CardHeader>
              <CardContent>
                <div className="grid grid-cols-1 md:grid-cols-2 gap-3">
                  {providerModels
                    .filter((model) =>
                      !filter ||
                      model.name.toLowerCase().includes(filter.toLowerCase()) ||
                      model.id.toLowerCase().includes(filter.toLowerCase())
                    )
                    .map((model) => (
                    <div
                      key={model.id}
                      className={`p-4 rounded-lg border transition-all ${
                        activeModel === model.id
                          ? 'bg-orange-500/10 border-orange-500/50'
                          : 'bg-zinc-800/50 border-zinc-700 hover:border-zinc-600'
                      }`}
                    >
                      <div className="flex items-start justify-between gap-2">
                        <div className="flex-1 min-w-0">
                          <p className="font-medium truncate" title={model.name}>
                            {model.name}
                          </p>
                          <p className="text-xs text-zinc-500 truncate mt-1" title={model.id}>
                            {model.id}
                          </p>
                        </div>
                        <Badge
                          variant={activeModel === model.id ? 'default' : 'outline'}
                          className={
                            activeModel === model.id
                              ? 'bg-orange-500 text-white'
                              : 'border-zinc-700'
                          }
                        >
                          {activeModel === model.id ? 'Active' : 'Available'}
                        </Badge>
                      </div>
                      <Button
                        onClick={() => handleSwitchModel(model.id)}
                        disabled={switching === model.id || activeModel === model.id}
                        variant={activeModel === model.id ? 'secondary' : 'outline'}
                        size="sm"
                        className="mt-3 w-full"
                      >
                        {switching === model.id ? (
                          <>
                            <RefreshCw className="w-4 h-4 mr-2 animate-spin" />
                            Switching...
                          </>
                        ) : activeModel === model.id ? (
                          'Active'
                        ) : (
                          'Switch to this model'
                        )}
                      </Button>
                    </div>
                  ))}
                </div>
              </CardContent>
            </Card>
          ))}
        </div>
      )}

      <div className="text-sm text-zinc-500">
        <p>ℹ️ Switching models restarts the Gateway to apply changes.</p>
      </div>
    </div>
  );
}