import React, { useEffect, useState } from 'react';
import { UploadIcon } from './icons/UploadIcon';
import { TrendingUpIcon } from './icons/TrendingUpIcon';
import { BugIcon } from './icons/BugIcon';
import { ClockIcon } from './icons/ClockIcon';
import { LightbulbIcon } from './icons/LightbulbIcon';
import { ExclamationTriangleIcon } from './icons/StatusIcons';
import apiService, { AnalyticsResponse, AgencyAnalyticsItem } from '../services/apiService';

// Agent performance is still static for now - would need separate API
const agentPerformance = [
    { name: 'Legal Agent', passRate: 85, avgIssues: 1.2, trend: 'up' },
    { name: 'Brand Agent', passRate: 68, avgIssues: 2.5, trend: 'down' },
    { name: 'Channel Best Practices Agent', passRate: 92, avgIssues: 0.8, trend: 'up' },
    { name: 'Channel Tech Specs Agent', passRate: 71, avgIssues: 1.9, trend: 'stable' },
];

const UpArrow = () => <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={3} stroke="currentColor" className="h-4 w-4"><path strokeLinecap="round" strokeLinejoin="round" d="M4.5 15.75l7.5-7.5 7.5 7.5" /></svg>;
const DownArrow = () => <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={3} stroke="currentColor" className="h-4 w-4"><path strokeLinecap="round" strokeLinejoin="round" d="M19.5 8.25l-7.5 7.5-7.5-7.5" /></svg>;
const StableLine = () => <svg xmlns="http://www.w3.org/2000/svg" fill="none" viewBox="0 0 24 24" strokeWidth={3} stroke="currentColor" className="h-4 w-4"><path strokeLinecap="round" strokeLinejoin="round" d="M3.75 12h16.5" /></svg>;

const TrendIndicator: React.FC<{ trend: 'up' | 'down' | 'stable' }> = ({ trend }) => {
    if (trend === 'up') {
        return <div className="flex items-center gap-1.5 text-success"><UpArrow/> Improving</div>;
    }
    if (trend === 'down') {
        return <div className="flex items-center gap-1.5 text-oliver-orange"><DownArrow/> Declining</div>;
    }
    return <div className="flex items-center gap-1.5 text-oliver-black"><StableLine/> Stable</div>;
};

export const Analytics: React.FC<{ agencyId?: string; isAdmin?: boolean }> = ({ agencyId, isAdmin }) => {
    const [analytics, setAnalytics] = useState<AnalyticsResponse | null>(null);
    const [agencyAnalytics, setAgencyAnalytics] = useState<AgencyAnalyticsItem[]>([]);
    const [isLoading, setIsLoading] = useState(true);

    useEffect(() => {
        const loadAnalytics = async () => {
            setIsLoading(true);
            try {
                const data = await apiService.getAnalytics(agencyId);
                setAnalytics(data);
            } catch (error) {
                console.error('Failed to load analytics:', error);
            } finally {
                setIsLoading(false);
            }
        };
        loadAnalytics();
    }, [agencyId]);

    useEffect(() => {
        if (!isAdmin) return;
        const loadAgencyAnalytics = async () => {
            try {
                const data = await apiService.getAnalyticsByAgency();
                setAgencyAnalytics(data.agencies);
            } catch (error) {
                console.error('Failed to load agency analytics:', error);
            }
        };
        loadAgencyAnalytics();
    }, [isAdmin]);

    // Calculate stats from API data
    // Exclude errors from denominator since they weren't successfully reviewed
    const reviewedCount = analytics
        ? (analytics.passed || 0) + (analytics.failed || 0) + (analytics.legal_review || 0)
        : 0;
    const passRate = reviewedCount > 0
        ? Math.round((analytics!.passed / reviewedCount) * 100)
        : 0;

    const stats = [
        { name: 'Proofs Reviewed', value: analytics?.total_reviews?.toString() || '0', icon: UploadIcon },
        { name: 'Pass Rate', value: `${passRate}%`, icon: TrendingUpIcon },
        { name: 'Failed Reviews', value: analytics?.failed?.toString() || '0', icon: BugIcon },
        { name: 'Analysis Errors', value: analytics?.errors?.toString() || '0', icon: ExclamationTriangleIcon },
        { name: 'Legal Review Required', value: analytics?.legal_review?.toString() || '0', icon: ClockIcon },
    ];

    return (
        <div className="p-4 sm:p-6 lg:p-8 h-full bg-white">
            <header className="mb-8">
                <h1 className="text-3xl lg:text-4xl font-semibold text-oliver-black">Performance analytics</h1>
                <p className="text-base lg:text-lg text-oliver-black mt-1">Overall usage and performance statistics for the tool.</p>
            </header>

            {/* Stats Cards */}
            <section>
                <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-5 gap-6">
                    {stats.map((stat) => {
                        const Icon = stat.icon;
                        return (
                            <div key={stat.name} className="bg-oliver-grey rounded-[10px] p-6 flex items-start border-2 border-grey-300 transition-all hover:shadow-lg">
                                <div className="p-3 rounded-full bg-oliver-grey text-oliver-black mr-4 flex-shrink-0">
                                    <Icon className="h-9 w-9" />
                                </div>
                                <div>
                                    <p className="text-sm font-medium text-oliver-black">{stat.name}</p>
                                    <p className="text-3xl font-bold text-oliver-black mt-1">{stat.value}</p>
                                </div>
                            </div>
                        );
                    })}
                </div>
            </section>

            {/* Per-Agency Breakdown (admin only) */}
            {isAdmin && agencyAnalytics.length > 0 && (
                <section className="mt-10">
                    <h2 className="text-2xl font-semibold text-oliver-black mb-4">Agency performance</h2>
                    <div className="bg-white rounded-[10px] shadow-md overflow-hidden border border-grey-300">
                        <div className="overflow-x-auto">
                            <table className="min-w-full">
                                <thead className="bg-oliver-sky">
                                    <tr>
                                        <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Agency</th>
                                        <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Proofs Reviewed</th>
                                        <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Pass Rate</th>
                                        <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Failed</th>
                                        <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Errors</th>
                                        <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Legal Review</th>
                                    </tr>
                                </thead>
                                <tbody className="divide-y divide-grey-300">
                                    {agencyAnalytics.map((agency, index) => {
                                        const reviewed = agency.passed + agency.failed + agency.legal_review;
                                        const rate = reviewed > 0 ? Math.round((agency.passed / reviewed) * 100) : 0;
                                        const isSelected = agencyId === agency.agency_id;
                                        return (
                                            <tr
                                                key={agency.agency_id}
                                                className={
                                                    isSelected
                                                        ? 'bg-blue-50'
                                                        : index % 2 === 0
                                                            ? 'bg-white'
                                                            : 'bg-oliver-grey'
                                                }
                                            >
                                                <td className="px-6 py-4 whitespace-nowrap text-sm font-medium text-oliver-black">
                                                    {agency.agency_name}
                                                    {isSelected && <span className="ml-2 text-xs text-oliver-black font-normal">(selected)</span>}
                                                </td>
                                                <td className="px-6 py-4 whitespace-nowrap text-sm text-oliver-black">{agency.total_reviews}</td>
                                                <td className="px-6 py-4 whitespace-nowrap text-sm font-semibold text-oliver-black">
                                                    <div className="flex items-center">
                                                        <span className={`h-2.5 w-2.5 rounded-full mr-3 ${rate >= 80 ? 'bg-success' : rate < 70 ? 'bg-error' : 'bg-warning'}`}></span>
                                                        {rate}%
                                                    </div>
                                                </td>
                                                <td className="px-6 py-4 whitespace-nowrap text-sm text-oliver-black">{agency.failed}</td>
                                                <td className="px-6 py-4 whitespace-nowrap text-sm text-oliver-black">{agency.errors}</td>
                                                <td className="px-6 py-4 whitespace-nowrap text-sm text-oliver-black">{agency.legal_review}</td>
                                            </tr>
                                        );
                                    })}
                                </tbody>
                            </table>
                        </div>
                    </div>
                </section>
            )}

            {/* AI Performance Summary */}
            <section className="mt-10">
                <h2 className="text-2xl font-semibold text-oliver-black mb-4">AI performance summary</h2>
                <div className="bg-white border border-oliver-sky border-l-8 text-oliver-black p-6 rounded-[10px] shadow-md flex items-start gap-4">
                    <div className="flex-shrink-0">
                        <LightbulbIcon className="h-9 w-9 text-oliver-orange" />
                    </div>
                    <div>
                        <p className="font-semibold text-oliver-black">Key Insight (Last 7 Days):</p>
                        <p className="mt-1 text-oliver-black">
                            A sharp decline in Best Practice adherence has been noted, primarily driven by proofs from the <strong>Barclays Q4 Social</strong> campaign. The Brand Guardian agent also shows a declining performance trend, suggesting a potential need for updated brand guideline training or proof review.
                        </p>
                    </div>
                </div>
            </section>

            {/* Agent Performance Table */}
            <section className="mt-10">
                <h2 className="text-2xl font-semibold text-oliver-black mb-4">Agent performance (last 7 days)</h2>
                <div className="bg-white rounded-[10px] shadow-md overflow-hidden border border-grey-300">
                    <div className="overflow-x-auto">
                        <table className="min-w-full">
                            <thead className="bg-oliver-sky">
                                <tr>
                                    <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Agent Name</th>
                                    <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Pass Rate</th>
                                    <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Avg. Issues per Proof</th>
                                    <th scope="col" className="px-6 py-3 text-left text-xs font-bold text-oliver-black uppercase tracking-wider">Performance Trend</th>
                                </tr>
                            </thead>
                            <tbody className="divide-y divide-grey-300">
                                {agentPerformance.map((agent, index) => (
                                    <tr key={agent.name} className={index % 2 === 0 ? 'bg-white' : 'bg-oliver-grey'}>
                                        <td className="px-6 py-4 whitespace-nowrap text-sm font-medium text-oliver-black">{agent.name}</td>
                                        <td className={`px-6 py-4 whitespace-nowrap text-sm font-semibold text-oliver-black`}>
                                            <div className="flex items-center">
                                                <span className={`h-2.5 w-2.5 rounded-full mr-3 ${agent.passRate >= 80 ? 'bg-oliver-green' : agent.passRate < 70 ? 'bg-oliver-gold' : 'bg-oliver-orange'}`}></span>
                                                {agent.passRate}%
                                            </div>
                                        </td>
                                        <td className="px-6 py-4 whitespace-nowrap text-sm text-oliver-black">{agent.avgIssues}</td>
                                        <td className="px-6 py-4 whitespace-nowrap text-sm font-medium">
                                            <TrendIndicator trend={agent.trend as 'up' | 'down' | 'stable'} />
                                        </td>
                                    </tr>
                                ))}
                            </tbody>
                        </table>
                    </div>
                </div>
            </section>
        </div>
    );
};