import { Metadata } from 'next';
import { notFound } from 'next/navigation';
import Link from 'next/link';
import { createClient } from '@supabase/supabase-js';
import { DashboardLayout } from '@/components/layout/sidebar';
import { Button } from '@/components/ui/button';
import { Badge } from '@/components/ui/badge';
import { ArrowLeft, FileText, FileType, FileIcon, FileCode, Edit3, Trash2, Clock, Folder } from 'lucide-react';
import { cn } from '@/lib/utils';
import { Document, DocumentType, DOCUMENT_TYPE_COLORS } from '@/types/documents';
import ReactMarkdown from 'react-markdown';
import remarkGfm from 'remark-gfm';

const typeIcons: Record<DocumentType, typeof FileText> = {
  markdown: FileType,
  text: FileText,
  pdf: FileIcon,
  code: FileCode,
};

function getSupabaseServerClient() {
  const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
  const supabaseServiceKey = process.env.SUPABASE_SERVICE_ROLE_KEY;

  if (!supabaseUrl || !supabaseServiceKey) {
    throw new Error('Server configuration error: Missing Supabase credentials');
  }

  return createClient(supabaseUrl, supabaseServiceKey, {
    auth: {
      autoRefreshToken: false,
      persistSession: false,
    },
  });
}

async function getDocument(id: string): Promise<Document | null> {
  try {
    const supabase = getSupabaseServerClient();

    const { data, error } = await supabase
      .from('mission_control_documents')
      .select('*')
      .eq('id', id)
      .single();

    if (error || !data) {
      console.error('Error fetching document:', error);
      return null;
    }

    return {
      id: data.id,
      title: data.title,
      content: data.content,
      type: data.type as DocumentType,
      folder: data.folder || 'General',
      tags: data.tags || [],
      createdAt: data.created_at,
      updatedAt: data.updated_at,
      size: data.size || 0,
      description: data.description,
    };
  } catch (err) {
    console.error('Failed to fetch document:', err);
    return null;
  }
}

function formatFileSize(bytes: number): string {
  if (bytes === 0) return '0 B';
  const k = 1024;
  const sizes = ['B', 'KB', 'MB', 'GB'];
  const i = Math.floor(Math.log(bytes) / Math.log(k));
  return parseFloat((bytes / Math.pow(k, i)).toFixed(1)) + ' ' + sizes[i];
}

function formatDate(dateString: string): string {
  const date = new Date(dateString);
  return date.toLocaleDateString('en-US', {
    month: 'short',
    day: 'numeric',
    year: 'numeric',
    hour: '2-digit',
    minute: '2-digit',
  });
}

interface PageProps {
  params: Promise<{ id: string }>;
}

export async function generateMetadata({ params }: PageProps): Promise<Metadata> {
  const { id } = await params;
  const document = await getDocument(id);
  
  return {
    title: document ? `${document.title} - Mission Control` : 'Document - Mission Control',
  };
}

export default async function DocumentPage({ params }: PageProps) {
  const { id } = await params;
  const document = await getDocument(id);

  if (!document) {
    notFound();
  }

  const Icon = typeIcons[document.type];
  const colorClass = DOCUMENT_TYPE_COLORS[document.type];

  return (
    <DashboardLayout>
      <div className="space-y-6">
        {/* Header with back button */}
        <div className="flex items-center gap-4">
          <Link href="/documents">
            <Button variant="outline" size="sm">
              <ArrowLeft className="w-4 h-4 mr-2" />
              Back to Documents
            </Button>
          </Link>
        </div>

        {/* Document Header */}
        <div className="border rounded-lg p-6 bg-card">
          <div className="flex flex-col sm:flex-row sm:items-start justify-between gap-4">
            <div className="flex items-start gap-4">
              <div className={cn('p-3 rounded-lg shrink-0', colorClass)}>
                <Icon className="w-6 h-6" />
              </div>
              <div className="min-w-0">
                <h1 className="text-xl sm:text-2xl font-semibold">{document.title}</h1>
                <div className="flex flex-wrap items-center gap-2 text-sm text-muted-foreground mt-2">
                  <span className="flex items-center gap-1">
                    <Folder className="w-4 h-4" />
                    {document.folder}
                  </span>
                  <span>•</span>
                  <span>{formatFileSize(document.size)}</span>
                  <span>•</span>
                  <span className="flex items-center gap-1">
                    <Clock className="w-4 h-4" />
                    Updated {formatDate(document.updatedAt)}
                  </span>
                </div>
              </div>
            </div>
            <div className="flex items-center gap-2 shrink-0">
              <Link href={`/documents?id=${document.id}&edit=true`}>
                <Button variant="outline" size="sm">
                  <Edit3 className="w-4 h-4 mr-2" />
                  Edit
                </Button>
              </Link>
            </div>
          </div>

          {/* Tags */}
          {document.tags.length > 0 && (
            <div className="flex flex-wrap gap-2 mt-4 pt-4 border-t">
              {document.tags.map((tag) => (
                <Badge key={tag} variant="secondary" className="text-xs">
                  #{tag}
                </Badge>
              ))}
            </div>
          )}
        </div>

        {/* Document Content */}
        <div className="border rounded-lg p-6 bg-card">
          <div className="prose prose-base dark:prose-invert max-w-none prose-headings:mt-6 prose-headings:mb-4 prose-p:my-3 prose-ul:my-3 prose-ol:my-3">
            <ReactMarkdown remarkPlugins={[remarkGfm]}>
              {document.content || '*No content*'}
            </ReactMarkdown>
          </div>
        </div>

        {/* Footer with back button */}
        <div className="flex items-center justify-center pt-4">
          <Link href="/documents">
            <Button variant="outline">
              <ArrowLeft className="w-4 h-4 mr-2" />
              Back to Documents
            </Button>
          </Link>
        </div>
      </div>
    </DashboardLayout>
  );
}