'use client'

import { useRouter } from 'next/navigation'
import { useEffect, useState } from 'react'
import { getApiBase, setToken, clearToken } from '../lib/auth'
import BrandingLogo from '../ui/BrandingLogo'

const DEFAULT_LOGIN_OPTIONS = {
  showJellyfinLogin: true,
  showLocalLogin: true,
  showForgotPassword: true,
  showSignupLink: true,
}

export default function LoginPage() {
  const router = useRouter()
  const [username, setUsername] = useState('')
  const [password, setPassword] = useState('')
  const [error, setError] = useState<string | null>(null)
  const [loading, setLoading] = useState(false)
  const [loginOptions, setLoginOptions] = useState(DEFAULT_LOGIN_OPTIONS)
  const primaryMode: 'jellyfin' | 'local' | null = loginOptions.showJellyfinLogin
    ? 'jellyfin'
    : loginOptions.showLocalLogin
      ? 'local'
      : null

  const submit = async (event: React.FormEvent, mode: 'local' | 'jellyfin') => {
    event.preventDefault()
    if (!primaryMode) {
      setError('Login is currently disabled. Contact an administrator.')
      return
    }
    setError(null)
    setLoading(true)
    try {
      clearToken()
      const baseUrl = getApiBase()
      const endpoint = mode === 'jellyfin' ? '/auth/jellyfin/login' : '/auth/login'
      const body = new URLSearchParams({ username, password })
      const response = await fetch(`${baseUrl}${endpoint}`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/x-www-form-urlencoded' },
        body,
      })
      if (!response.ok) {
        throw new Error('Login failed')
      }
      const data = await response.json()
      if (data?.access_token) {
        setToken(data.access_token)
        if (typeof window !== 'undefined') {
          window.location.href = '/'
          return
        }
        router.push('/')
        return
      }
      throw new Error('Login failed')
    } catch (err) {
      console.error(err)
      setError('Invalid username or password.')
    } finally {
      setLoading(false)
    }
  }

  useEffect(() => {
    let active = true
    const loadLoginOptions = async () => {
      try {
        const baseUrl = getApiBase()
        const response = await fetch(`${baseUrl}/site/public`)
        if (!response.ok) {
          return
        }
        const data = await response.json()
        const login = data?.login ?? {}
        if (!active) return
        setLoginOptions({
          showJellyfinLogin: login.showJellyfinLogin !== false,
          showLocalLogin: login.showLocalLogin !== false,
          showForgotPassword: login.showForgotPassword !== false,
          showSignupLink: login.showSignupLink !== false,
        })
      } catch (err) {
        console.error(err)
      }
    }
    void loadLoginOptions()
    return () => {
      active = false
    }
  }, [])

  const loginHelpText = (() => {
    if (loginOptions.showJellyfinLogin && loginOptions.showLocalLogin) {
      return 'Use your Jellyfin account, or sign in with a local Magent admin account.'
    }
    if (loginOptions.showJellyfinLogin) {
      return 'Use your Jellyfin account to sign in.'
    }
    if (loginOptions.showLocalLogin) {
      return 'Use your local Magent admin account to sign in.'
    }
    return 'No sign-in methods are currently available. Contact an administrator.'
  })()

  return (
    <main className="card auth-card">
      <BrandingLogo className="brand-logo brand-logo--login" />
      <h1>Sign in</h1>
      <p className="lede">{loginHelpText}</p>
      <form
        onSubmit={(event) => {
          if (!primaryMode) {
            event.preventDefault()
            setError('Login is currently disabled. Contact an administrator.')
            return
          }
          void submit(event, primaryMode)
        }}
        className="auth-form"
      >
        <label>
          Username
          <input
            value={username}
            onChange={(event) => setUsername(event.target.value)}
            autoComplete="username"
          />
        </label>
        <label>
          Password
          <input
            type="password"
            value={password}
            onChange={(event) => setPassword(event.target.value)}
            autoComplete="current-password"
          />
        </label>
        {error && <div className="error-banner">{error}</div>}
        <div className="auth-actions">
          {loginOptions.showJellyfinLogin ? (
            <button type="submit" disabled={loading}>
              {loading ? 'Signing in...' : 'Login with Jellyfin account'}
            </button>
          ) : null}
        </div>
        {loginOptions.showLocalLogin ? (
          <button
            type="button"
            className="ghost-button"
            disabled={loading}
            onClick={(event) => submit(event, 'local')}
          >
            Sign in with Magent account
          </button>
        ) : null}
        {loginOptions.showForgotPassword ? (
          <a className="ghost-button" href="/forgot-password">
            Forgot password?
          </a>
        ) : null}
        {loginOptions.showSignupLink ? (
          <a className="ghost-button" href="/signup">
            Have an invite? Create your account (Jellyfin + Magent)
          </a>
        ) : null}
        {!loginOptions.showJellyfinLogin && !loginOptions.showLocalLogin ? (
          <div className="error-banner">Login is currently disabled. Contact an administrator.</div>
        ) : null}
      </form>
    </main>
  )
}