'use client';

import { useState, useEffect } from 'react';
import { db, Item } from '@/lib/db';
import { inventoryApi } from '@/lib/api';
import PageShell from '@/components/PageShell';
import { History, Search, Activity, ArrowDownCircle, ArrowUpCircle, RefreshCw } from 'lucide-react';
import { cn } from '@/lib/utils';
import { fetchAndCacheItems } from '@/lib/sync';
import StatCard from '@/components/StatCard';
import LogsTable from '@/components/LogsTable';

export default function LogsPage() {
  const [auditLogs, setAuditLogs] = useState<any[]>([]);
  const [inventory, setInventory] = useState<Item[]>([]);
  const [loading, setLoading] = useState(true);
  const [searchQuery, setSearchQuery] = useState('');
  const [filterAction, setFilterAction] = useState('ALL');

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

  const loadData = async () => {
    setLoading(true);
    try {
      // 1. First, try to get fresh items to resolve names
      let freshItems: Item[] = [];
      try {
        freshItems = await fetchAndCacheItems();
      } catch (itemErr) {
        console.warn("Item sync failed, using local cache for names", itemErr);
        freshItems = await db.items.toArray();
      }
      setInventory(freshItems);
      
      // 2. Then, fetch fresh logs
      const logs = await inventoryApi.getAuditLogs(100);
      
      // 3. Pre-resolve names to avoid UI flickering/mismatches
      const enrichedLogs = (logs || []).map((log: any) => {
        // [AUDIT HARDENING] Prioritize the historical snapshot from the backend
        if (log.target_item_name) {
          return { ...log, resolved_name: log.target_item_name };
        }

        // Fallback for legacy logs or system operations
        const hasTarget = log.target_item_id && String(log.target_item_id) !== 'null';
        const item = hasTarget ? freshItems.find(i => String(i.id) === String(log.target_item_id)) : null;
        
        return {
          ...log,
          resolved_name: item ? item.name : (hasTarget ? `Item #${log.target_item_id}` : "System Operation")
        };
      });

      setAuditLogs(enrichedLogs);
    } catch (err: any) {
      console.error("Critical log load failure:", err);
    } finally {
      setLoading(false);
    }
  };

  const filteredLogs = auditLogs.filter(log => {
    const matchesSearch = (log.resolved_name || '').toLowerCase().includes(searchQuery.toLowerCase()) ||
                         log.action.toLowerCase().includes(searchQuery.toLowerCase()) ||
                         (log.username || '').toLowerCase().includes(searchQuery.toLowerCase());
    
    const matchesAction = filterAction === 'ALL' || log.action.includes(filterAction);
    
    return matchesSearch && matchesAction;
  });

  // Calculate stats
  const totalCount = auditLogs.length;
  const inCount = auditLogs.filter(l => l.action.includes('IN') || l.action.includes('ADD')).length;
  const outCount = auditLogs.filter(l => l.action.includes('OUT') || l.action.includes('TRASH') || l.action.includes('DELETE')).length;
  const criticalLogsCount = auditLogs.filter(l => l.action.includes('DELETE') || l.action.includes('TRASH')).length;

  const mostActiveUser = auditLogs.length > 0 ? 
    Object.entries(auditLogs.reduce((acc: any, curr) => {
      const user = curr.username || 'System';
      acc[user] = (acc[user] || 0) + 1;
      return acc;
    }, {})).sort((a: any, b: any) => b[1] - a[1])[0]?.[0] : 'N/A';

  return (
    <PageShell>
      <main className="p-4 md:p-8 max-w-7xl mx-auto space-y-3 md:space-y-6 mb-20">
        <header className="flex flex-col sm:flex-row sm:items-end justify-between gap-3 md:gap-4 mb-6 md:mb-8">
          <div className="flex items-center gap-4">
            <div className="p-4 bg-primary/10 text-primary border border-primary/20">
              <History size={28} className="md:w-8 md:h-8" />
            </div>
            <div>
              <h1 className="text-2xl md:text-3xl font-normal tracking-tight text-white leading-tight">Operations Audit</h1>
              <p className="text-xs md:text-sm text-secondary font-normal mt-0.5">Real-time Intervention Tracking</p>
            </div>
          </div>
          
          <div className="flex gap-2 ml-auto sm:ml-0">
             <button 
               onClick={loadData}
               disabled={loading}
               className="flex items-center gap-2 px-5 py-2.5 bg-surface border border-slate-800 text-secondary hover:text-white text-xs font-normal transition-all active:scale-95 disabled:opacity-50"
             >
               <RefreshCw size={14} className={cn(loading && "animate-spin")} />
               Sync Logs
             </button>
          </div>
        </header>

        {/* Stats Grid */}
        <section className="grid grid-cols-2 lg:grid-cols-4 gap-2.5 md:gap-4">
          <StatCard
            label="Total Events"
            value={totalCount}
            icon={Activity}
          />
          <StatCard
            label="Inbound"
            value={inCount}
            icon={ArrowDownCircle}
          />
          <StatCard
            label="Outbound"
            value={outCount}
            icon={ArrowUpCircle}
          />
          <StatCard
            label="Integrity"
            value={totalCount - criticalLogsCount}
            icon={History}
          />
        </section>

        <section className="space-y-3 md:space-y-4">
          <div className="relative group">
            <input 
              type="text"
              placeholder="Filter by user, action or asset..."
              value={searchQuery}
              onChange={(e) => setSearchQuery(e.target.value)}
              className="w-full bg-surface/50 border border-slate-800 py-3 lg:py-4 xl:py-5.5 pr-4 pl-12 text-sm lg:text-base xl:text-lg lg:text-xl xl:text-2xl lg:text-3xl xl:text-4xl focus:border-primary outline-none transition-all placeholder:text-secondary"
            />
            <div className="absolute left-4 top-1/2 -translate-y-1/2 text-secondary transition-colors group-focus-within:text-primary">
              <Search size={18} />
            </div>
          </div>

          <div className="flex items-center gap-2 overflow-x-auto no-scrollbar pb-1 px-1 -mx-1">
            <button
              onClick={() => setFilterAction('ALL')}
              className={cn(
                "px-5 py-2 text-xs font-normal transition-all whitespace-nowrap border",
                filterAction === 'ALL' 
                  ? "bg-white text-slate-950 border-white" 
                  : "bg-surface/70 text-secondary border-slate-800 hover:border-slate-700"
              )}
            >
              All Streams
            </button>
            {['ADD', 'REMOVE', 'ADJUST', 'DELETE', 'LOGIN'].map((f) => (
              <button
                key={f}
                onClick={() => setFilterAction(f)}
                className={cn(
                  "px-5 py-2 text-xs font-normal transition-all whitespace-nowrap border",
                  filterAction === f 
                    ? "bg-primary text-white border-primary" 
                    : "bg-surface/70 text-secondary border-slate-800 hover:border-slate-700"
                )}
              >
                {f}
              </button>
            ))}
          </div>
        </section>

        <section className="space-y-3">
          <LogsTable logs={filteredLogs} loading={loading} />
        </section>
      </main>
    </PageShell>
  );
}