import { useState, useEffect } from 'react'
import {
    Routes,
    Route,
    Navigate,
    useNavigate,
    useLocation
} from 'react-router-dom'
import {
    LayoutDashboard,
    Key,
    Upload,
    Cloud,
    LogOut,
    Menu,
    X,
    Server,
    Users
} from 'lucide-react'
import clsx from 'clsx'

import AccountManager from './components/AccountManager'
import ApiTester from './components/ApiTester'
import BatchImport from './components/BatchImport'
import VercelSync from './components/VercelSync'
import Login from './components/Login'
import LandingPage from './components/LandingPage'
import LanguageToggle from './components/LanguageToggle'
import { useI18n } from './i18n'

function Dashboard({ token, onLogout, config, fetchConfig, showMessage, message }) {
    const { t } = useI18n()
    const [activeTab, setActiveTab] = useState('accounts')
    const [sidebarOpen, setSidebarOpen] = useState(false)
    const [loading, setLoading] = useState(false)

    const navItems = [
        { id: 'accounts', label: t('nav.accounts.label'), icon: Users, description: t('nav.accounts.desc') },
        { id: 'test', label: t('nav.test.label'), icon: Server, description: t('nav.test.desc') },
        { id: 'import', label: t('nav.import.label'), icon: Upload, description: t('nav.import.desc') },
        { id: 'vercel', label: t('nav.vercel.label'), icon: Cloud, description: t('nav.vercel.desc') },
    ]

    const authFetch = async (url, options = {}) => {
        const headers = {
            ...options.headers,
            'Authorization': `Bearer ${token}`
        }
        const res = await fetch(url, { ...options, headers })

        if (res.status === 401) {
            onLogout()
            throw new Error(t('auth.expired'))
        }
        return res
    }

    const renderTab = () => {
        switch (activeTab) {
            case 'accounts':
                return <AccountManager config={config} onRefresh={fetchConfig} onMessage={showMessage} authFetch={authFetch} />
            case 'test':
                return <ApiTester config={config} onMessage={showMessage} authFetch={authFetch} />
            case 'import':
                return <BatchImport onRefresh={fetchConfig} onMessage={showMessage} authFetch={authFetch} />
            case 'vercel':
                return <VercelSync onMessage={showMessage} authFetch={authFetch} />
            default:
                return null
        }
    }

    return (
        <div className="flex h-screen bg-background overflow-hidden text-foreground">
            {sidebarOpen && (
                <div
                    className="fixed inset-0 bg-background/80 backdrop-blur-sm z-40 lg:hidden"
                    onClick={() => setSidebarOpen(false)}
                />
            )}

            <aside className={clsx(
                "fixed lg:static inset-y-0 left-0 z-50 w-64 bg-card border-r border-border transition-transform duration-300 ease-in-out lg:transform-none flex flex-col shadow-2xl lg:shadow-none",
                sidebarOpen ? "translate-x-0" : "-translate-x-full"
            )}>
                <div className="p-6">
                    <div className="flex items-center gap-2.5 font-bold text-xl text-foreground tracking-tight">
                        <div className="w-8 h-8 rounded-lg bg-primary flex items-center justify-center text-primary-foreground shadow-lg shadow-primary/20">
                            <LayoutDashboard className="w-5 h-5" />
                        </div>
                        <span>DS2API</span>
                    </div>
                    <div className="flex items-center justify-between mt-2">
                        <p className="text-[10px] text-muted-foreground font-semibold tracking-[0.1em] uppercase opacity-60 px-1">{t('sidebar.onlineAdminConsole')}</p>
                        <LanguageToggle />
                    </div>
                </div>

                <nav className="flex-1 px-3 space-y-1 overflow-y-auto pt-2">
                    {navItems.map((item) => {
                        const Icon = item.icon
                        const isActive = activeTab === item.id
                        return (
                            <button
                                key={item.id}
                                onClick={() => {
                                    setActiveTab(item.id)
                                    setSidebarOpen(false)
                                }}
                                className={clsx(
                                    "w-full flex items-center gap-3 px-3 py-2.5 rounded-lg text-sm font-medium transition-all duration-200 group border",
                                    isActive
                                        ? "bg-secondary text-primary border-border shadow-sm"
                                        : "text-muted-foreground border-transparent hover:bg-secondary/80 hover:text-foreground"
                                )}
                            >
                                <Icon className={clsx("w-4 h-4 transition-colors", isActive ? "text-primary" : "text-muted-foreground group-hover:text-foreground")} />
                                <span className="flex-1 text-left">{item.label}</span>
                                {isActive && <div className="w-1.5 h-1.5 rounded-full bg-primary" />}
                            </button>
                        )
                    })}
                </nav>

                <div className="p-4 border-t border-border bg-card">
                    <div className="space-y-4">
                        <div className="flex items-center justify-between text-sm px-1">
                            <span className="text-muted-foreground font-semibold text-[10px] uppercase tracking-wider">{t('sidebar.systemStatus')}</span>
                            <span className="flex items-center gap-1.5 text-[10px] font-bold text-emerald-500 bg-emerald-500/10 px-2 py-0.5 rounded-full border border-emerald-500/20">
                                <span className="w-1.5 h-1.5 rounded-full bg-emerald-500 animate-pulse"></span>
                                {t('sidebar.statusOnline')}
                            </span>
                        </div>
                        <div className="grid grid-cols-2 gap-2">
                            <div className="bg-background rounded-lg p-3 border border-border shadow-sm">
                                <div className="text-[9px] text-muted-foreground font-bold uppercase tracking-wider mb-0.5 opacity-70">{t('sidebar.accounts')}</div>
                                <div className="text-lg font-bold text-foreground leading-tight">{config.accounts?.length || 0}</div>
                            </div>
                            <div className="bg-background rounded-lg p-3 border border-border shadow-sm">
                                <div className="text-[9px] text-muted-foreground font-bold uppercase tracking-wider mb-0.5 opacity-70">{t('sidebar.keys')}</div>
                                <div className="text-lg font-bold text-foreground">{config.keys?.length || 0}</div>
                            </div>
                        </div>
                        <button
                            onClick={onLogout}
                            className="w-full h-10 flex items-center justify-center gap-2 rounded-lg border border-border text-xs font-medium text-muted-foreground hover:bg-destructive/10 hover:text-destructive hover:border-destructive/20 transition-all"
                        >
                            <LogOut className="w-3.5 h-3.5" />
                            {t('sidebar.signOut')}
                        </button>
                    </div>
                </div>
            </aside>

            <main className="flex-1 flex flex-col min-w-0 overflow-hidden relative">
                <header className="lg:hidden h-14 flex items-center justify-between px-4 border-b border-border bg-card">
                    <div className="flex items-center gap-2">
                        <div className="w-6 h-6 rounded bg-primary flex items-center justify-center text-primary-foreground text-[10px]">
                            <LayoutDashboard className="w-3.5 h-3.5" />
                        </div>
                        <span className="font-semibold text-sm">DS2API</span>
                    </div>
                    <div className="flex items-center gap-2">
                        <LanguageToggle />
                        <button
                            onClick={() => setSidebarOpen(true)}
                            className="p-2 -mr-2 text-muted-foreground hover:text-foreground"
                        >
                            <Menu className="w-5 h-5" />
                        </button>
                    </div>
                </header>

                <div className="flex-1 overflow-auto bg-background p-4 lg:p-10">
                    <div className="max-w-6xl mx-auto space-y-4 lg:space-y-6">
                        <div className="hidden lg:block mb-8">
                            <h1 className="text-3xl font-bold tracking-tight mb-2">
                                {navItems.find(n => n.id === activeTab)?.label}
                            </h1>
                            <p className="text-muted-foreground">
                                {navItems.find(n => n.id === activeTab)?.description}
                            </p>
                        </div>

                        {message && (
                            <div className={clsx(
                                "p-4 rounded-lg border flex items-center gap-3 animate-in fade-in slide-in-from-top-2",
                                message.type === 'error' ? "bg-destructive/10 border-destructive/20 text-destructive" :
                                    "bg-emerald-500/10 border-emerald-500/20 text-emerald-500"
                            )}>
                                {message.type === 'error' ? <X className="w-5 h-5" /> : <div className="w-5 h-5 rounded-full border-2 border-emerald-500 flex items-center justify-center text-[10px]">✓</div>}
                                {message.text}
                            </div>
                        )}

                        <div className="animate-in fade-in duration-500">
                            {renderTab()}
                        </div>
                    </div>
                </div>
            </main>
        </div>
    )
}

export default function App() {
    const { t } = useI18n()
    const navigate = useNavigate()
    const location = useLocation()
    const [config, setConfig] = useState({ keys: [], accounts: [] })
    const [loading, setLoading] = useState(true)
    const [message, setMessage] = useState(null)
    const [token, setToken] = useState(null)
    const [authChecking, setAuthChecking] = useState(true)

    const isProduction = import.meta.env.MODE === 'production'
    const isAdminRoute = location.pathname.startsWith('/admin') || isProduction

    useEffect(() => {
        // Only check auth status on admin routes.
        if (!isAdminRoute) {
            setAuthChecking(false)
            return
        }

        const checkAuth = async () => {
            const storedToken = localStorage.getItem('ds2api_token') || sessionStorage.getItem('ds2api_token')
            const expiresAt = parseInt(localStorage.getItem('ds2api_token_expires') || sessionStorage.getItem('ds2api_token_expires') || '0')

            if (storedToken && expiresAt > Date.now()) {
                try {
                    const res = await fetch('/admin/verify', {
                        headers: { 'Authorization': `Bearer ${storedToken}` }
                    })
                    if (res.ok) {
                        setToken(storedToken)
                    } else {
                        handleLogout()
                    }
                } catch {
                    setToken(storedToken)
                }
            }
            setAuthChecking(false)
        }
        checkAuth()
    }, [isAdminRoute])

    const fetchConfig = async () => {
        if (!token) return
        try {
            setLoading(true)
            const res = await fetch('/admin/config', {
                headers: { 'Authorization': `Bearer ${token}` }
            })
            if (res.ok) {
                const data = await res.json()
                setConfig(data)
            }
        } catch (e) {
            console.error('Failed to fetch config:', e)
            showMessage('error', t('errors.fetchConfig', { error: e.message }))
        } finally {
            setLoading(false)
        }
    }

    useEffect(() => {
        if (token) {
            fetchConfig()
        }
    }, [token])

    const showMessage = (type, text) => {
        setMessage({ type, text })
        setTimeout(() => setMessage(null), 5000)
    }

    const handleLogin = (newToken) => {
        setToken(newToken)
    }

    const handleLogout = () => {
        setToken(null)
        localStorage.removeItem('ds2api_token')
        localStorage.removeItem('ds2api_token_expires')
        sessionStorage.removeItem('ds2api_token')
        sessionStorage.removeItem('ds2api_token_expires')
    }

    // Wait for auth checks on admin routes.
    if (isAdminRoute && authChecking) {
        return (
            <div className="min-h-screen flex items-center justify-center bg-background">
                <div className="flex flex-col items-center gap-4">
                    <div className="w-8 h-8 border-4 border-primary border-t-transparent rounded-full animate-spin"></div>
                    <p className="text-muted-foreground animate-pulse">{t('auth.checking')}</p>
                </div>
            </div>
        )
    }

    return (
        <Routes>
            {!isProduction && (
                <Route path="/" element={<LandingPage onEnter={() => navigate('/admin')} />} />
            )}
            <Route path={isProduction ? "/" : "/admin"} element={
                token ? (
                    <Dashboard
                        token={token}
                        onLogout={handleLogout}
                        config={config}
                        fetchConfig={fetchConfig}
                        showMessage={showMessage}
                        message={message}
                    />
                ) : (
                    <div className="min-h-screen flex flex-col bg-background relative overflow-hidden">
                        <div className="absolute top-0 left-0 w-full h-full overflow-hidden pointer-events-none z-0">
                            <div className="absolute top-[-10%] right-[-10%] w-[50%] h-[50%] bg-primary/5 rounded-full blur-[120px]"></div>
                            <div className="absolute bottom-[-10%] left-[-10%] w-[50%] h-[50%] bg-accent/5 rounded-full blur-[120px]"></div>
                        </div>

                        {message && (
                            <div className={clsx(
                                "fixed top-4 right-4 z-50 px-4 py-3 rounded-lg shadow-lg border animate-in slide-in-from-top-2 fade-in",
                                message.type === 'error' ? "bg-destructive/10 border-destructive/20 text-destructive" :
                                    "bg-primary/10 border-primary/20 text-primary"
                            )}>
                                {message.text}
                            </div>
                        )}
                        <Login onLogin={handleLogin} onMessage={showMessage} />
                    </div>
                )
            } />
            <Route path="*" element={<Navigate to="/" replace />} />
        </Routes>
    )
}
