import { useState, useRef, useEffect } from 'react'
import { useLocation } from 'react-router-dom'
import { ChevronDown, LogOut, Shield, Lock, AlertCircle, CheckCircle } from 'lucide-react'
import { useAuth } from '../contexts/AuthContext'
import { getInitials, api } from '../utils/api'
import { useLanguage } from '../i18n/LanguageContext'
import Modal from './Modal'
import ThemeToggle from './ThemeToggle'

const PAGE_TITLE_KEYS = {
  '/': 'header.dashboard',
  '/posts': 'header.posts',
  '/calendar': 'header.calendar',
  '/assets': 'header.assets',
  '/artefacts': 'header.artefacts',
  '/campaigns': 'header.campaigns',
  '/brands': 'header.brands',
  '/finance': 'header.finance',
  '/budgets': 'header.budgets',
  '/projects': 'header.projects',
  '/tasks': 'header.tasks',
  '/issues': 'header.issues',
  '/team': 'header.team',
  '/settings': 'header.settings',
}

const ROLE_INFO = {
  superadmin: { labelKey: 'header.superadmin', color: 'bg-purple-100 text-purple-700', icon: '👑' },
  manager: { labelKey: 'header.manager', color: 'bg-blue-100 text-blue-700', icon: '📊' },
  contributor: { labelKey: 'header.contributor', color: 'bg-green-100 text-green-700', icon: '✏️' },
}

export default function Header() {
  const { user, logout } = useAuth()
  const { t } = useLanguage()
  const [showDropdown, setShowDropdown] = useState(false)
  const [showPasswordModal, setShowPasswordModal] = useState(false)
  const [passwordForm, setPasswordForm] = useState({ currentPassword: '', newPassword: '', confirmPassword: '' })
  const [passwordError, setPasswordError] = useState('')
  const [passwordSuccess, setPasswordSuccess] = useState('')
  const [passwordSaving, setPasswordSaving] = useState(false)
  const dropdownRef = useRef(null)
  const location = useLocation()

  function getPageTitle(pathname) {
    if (PAGE_TITLE_KEYS[pathname]) return t(PAGE_TITLE_KEYS[pathname])
    if (pathname.startsWith('/projects/')) return t('header.projectDetails')
    if (pathname.startsWith('/campaigns/')) return t('header.campaignDetails')
    return t('header.page')
  }
  const pageTitle = getPageTitle(location.pathname)

  useEffect(() => {
    const handleClickOutside = (e) => {
      if (dropdownRef.current && !dropdownRef.current.contains(e.target)) {
        setShowDropdown(false)
      }
    }
    document.addEventListener('mousedown', handleClickOutside)
    return () => document.removeEventListener('mousedown', handleClickOutside)
  }, [])

  const handlePasswordChange = async () => {
    setPasswordError('')
    setPasswordSuccess('')
    if (passwordForm.newPassword !== passwordForm.confirmPassword) {
      setPasswordError(t('header.passwordMismatch'))
      return
    }
    if (passwordForm.newPassword.length < 6) {
      setPasswordError(t('header.passwordMinLength'))
      return
    }
    setPasswordSaving(true)
    try {
      await api.patch('/users/me/password', {
        currentPassword: passwordForm.currentPassword,
        newPassword: passwordForm.newPassword,
      })
      setPasswordSuccess(t('header.passwordUpdateSuccess'))
      setPasswordForm({ currentPassword: '', newPassword: '', confirmPassword: '' })
      setTimeout(() => setShowPasswordModal(false), 1500)
    } catch (err) {
      setPasswordError(err.message || t('header.passwordUpdateFailed'))
    } finally {
      setPasswordSaving(false)
    }
  }

  const openPasswordModal = () => {
    setShowDropdown(false)
    setPasswordForm({ currentPassword: '', newPassword: '', confirmPassword: '' })
    setPasswordError('')
    setPasswordSuccess('')
    setShowPasswordModal(true)
  }

  const roleInfo = ROLE_INFO[user?.role] || ROLE_INFO.contributor

  return (
    <>
    <header className="h-16 bg-white border-b border-border flex items-center justify-between px-6 shrink-0 sticky top-0 z-20">
      {/* Page title */}
      <div>
        <h2 className="text-xl font-bold text-text-primary">{pageTitle}</h2>
      </div>

      {/* Right side */}
      <div className="flex items-center gap-2">
        {/* Theme toggle */}
        <ThemeToggle />

        {/* User menu */}
        <div ref={dropdownRef} className="relative">
          <button
            onClick={() => setShowDropdown(!showDropdown)}
            className="flex items-center gap-3 px-3 py-2 rounded-lg hover:bg-surface-tertiary transition-colors"
          >
            <div className={`w-8 h-8 rounded-full flex items-center justify-center text-white text-xs font-semibold ${
              user?.role === 'superadmin'
                ? 'bg-gradient-to-br from-purple-500 to-pink-500'
                : 'bg-gradient-to-br from-blue-500 to-indigo-500'
            }`}>
              {getInitials(user?.name)}
            </div>
            <div className="text-start hidden sm:block">
              <p className="text-sm font-medium text-text-primary">
                {user?.name || 'User'}
              </p>
              <p className={`text-[10px] font-medium ${roleInfo.color.split(' ')[1]}`}>
                {roleInfo.icon} {t(roleInfo.labelKey)}
              </p>
            </div>
            <ChevronDown className={`w-4 h-4 text-text-tertiary transition-transform ${showDropdown ? 'rotate-180' : ''}`} />
          </button>

          {showDropdown && (
            <div className="absolute end-0 top-full mt-2 w-64 bg-white rounded-xl shadow-lg border border-border overflow-hidden animate-scale-in">
              {/* User info */}
              <div className="px-4 py-3 border-b border-border-light bg-surface-secondary">
                <p className="text-sm font-semibold text-text-primary">{user?.name}</p>
                <p className="text-xs text-text-tertiary">{user?.email}</p>
                <div className={`inline-flex items-center gap-1 text-[10px] font-medium px-2 py-0.5 rounded-full mt-2 ${roleInfo.color}`}>
                  <span>{roleInfo.icon}</span>
                  {t(roleInfo.labelKey)}
                </div>
              </div>

              {/* Menu items */}
              <div className="py-2">
                {user?.role === 'superadmin' && (
                  <button
                    onClick={() => {
                      setShowDropdown(false)
                      window.location.href = '/users'
                    }}
                    className="w-full flex items-center gap-3 px-4 py-2.5 hover:bg-surface-secondary transition-colors text-start"
                  >
                    <Shield className="w-4 h-4 text-text-tertiary" />
                    <span className="text-sm text-text-primary">{t('header.userManagement')}</span>
                  </button>
                )}

                <button
                  onClick={openPasswordModal}
                  className="w-full flex items-center gap-3 px-4 py-2.5 hover:bg-surface-secondary transition-colors text-start"
                >
                  <Lock className="w-4 h-4 text-text-tertiary" />
                  <span className="text-sm text-text-primary">{t('header.changePassword')}</span>
                </button>

                <button
                  onClick={() => {
                    setShowDropdown(false)
                    logout()
                  }}
                  className="w-full flex items-center gap-3 px-4 py-2.5 hover:bg-red-50 transition-colors text-left group"
                >
                  <LogOut className="w-4 h-4 text-text-tertiary group-hover:text-red-500" />
                  <span className="text-sm text-text-primary group-hover:text-red-500">{t('header.signOut')}</span>
                </button>
              </div>
            </div>
          )}
        </div>
      </div>
    </header>

    {/* Change Password Modal */}
    <Modal isOpen={showPasswordModal} onClose={() => setShowPasswordModal(false)} title={t('header.changePassword')} size="md">
      <div className="space-y-4">
        <div>
          <label className="block text-sm font-medium text-text-primary mb-1">{t('header.currentPassword')}</label>
          <input
            type="password"
            value={passwordForm.currentPassword}
            onChange={e => { setPasswordForm(f => ({ ...f, currentPassword: e.target.value })); setPasswordError('') }}
            className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
            placeholder="••••••••"
          />
        </div>
        <div>
          <label className="block text-sm font-medium text-text-primary mb-1">{t('header.newPassword')}</label>
          <input
            type="password"
            value={passwordForm.newPassword}
            onChange={e => { setPasswordForm(f => ({ ...f, newPassword: e.target.value })); setPasswordError('') }}
            className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
            placeholder="••••••••"
            minLength={6}
          />
        </div>
        <div>
          <label className="block text-sm font-medium text-text-primary mb-1">{t('header.confirmNewPassword')}</label>
          <input
            type="password"
            value={passwordForm.confirmPassword}
            onChange={e => { setPasswordForm(f => ({ ...f, confirmPassword: e.target.value })); setPasswordError('') }}
            className="w-full px-3 py-2 text-sm border border-border rounded-lg focus:outline-none focus:ring-2 focus:ring-brand-primary/20 focus:border-brand-primary"
            placeholder="••••••••"
            minLength={6}
          />
        </div>

        {passwordError && (
          <div className="flex items-center gap-2 p-3 bg-red-500/10 border border-red-500/30 rounded-lg">
            <AlertCircle className="w-4 h-4 text-red-500 shrink-0" />
            <p className="text-sm text-red-500">{passwordError}</p>
          </div>
        )}

        {passwordSuccess && (
          <div className="flex items-center gap-2 p-3 bg-green-500/10 border border-green-500/30 rounded-lg">
            <CheckCircle className="w-4 h-4 text-green-500 shrink-0" />
            <p className="text-sm text-green-500">{passwordSuccess}</p>
          </div>
        )}

        <div className="flex items-center justify-end gap-3 pt-4 border-t border-border">
          <button
            onClick={() => setShowPasswordModal(false)}
            className="px-4 py-2 text-sm font-medium text-text-secondary hover:bg-surface-tertiary rounded-lg"
          >
            {t('common.cancel')}
          </button>
          <button
            onClick={handlePasswordChange}
            disabled={!passwordForm.currentPassword || !passwordForm.newPassword || !passwordForm.confirmPassword || passwordSaving}
            className="px-5 py-2 bg-brand-primary text-white rounded-lg text-sm font-medium hover:bg-brand-primary-light disabled:opacity-50 disabled:cursor-not-allowed shadow-sm"
          >
            {passwordSaving ? t('header.saving') : t('header.updatePassword')}
          </button>
        </div>
      </div>
    </Modal>
    </>
  )
}