import { useCallback, useRef, useState } from 'react'
import { useNavigate } from 'react-router-dom'
import { driver, type DriveStep } from 'driver.js'
import 'driver.js/dist/driver.css'

const TOUR_PENDING_KEY = 'gj-tour-pending-step'

export function hasPendingTourStep(): string | null {
  return localStorage.getItem(TOUR_PENDING_KEY)
}

export function clearPendingTourStep(): void {
  localStorage.removeItem(TOUR_PENDING_KEY)
}

function driverDefaults() {
  return {
    showProgress: true,
    animate: true,
    allowClose: true,
    overlayColor: 'rgba(0, 0, 0, 0.6)',
    stagePadding: 8,
    stageRadius: 12,
    popoverClass: 'gj-tour-popover',
    nextBtnText: 'Next',
    prevBtnText: 'Back',
    doneBtnText: 'Got it!',
    progressText: '{{current}} of {{total}}',
  } as const
}

function getHomeSteps(isMobile: boolean): DriveStep[] {
  return [
    {
      element: '#tour-title-input',
      popover: {
        title: 'Give it a Title',
        description: 'Start by naming your gratitude entry. A short title helps you find it later.',
        side: 'bottom',
        align: 'center',
      },
    },
    {
      element: '#tour-content-textarea',
      popover: {
        title: 'Write Your Thoughts',
        description: 'Pour out what you\'re grateful for today. There\'s no right or wrong — just write from the heart.',
        side: isMobile ? 'top' : 'bottom',
        align: 'center',
      },
    },
    {
      element: '#tour-save-btn',
      popover: {
        title: 'Save Your Entry',
        description: 'Hit save and your entry is securely encrypted and stored. Only you can read it.',
        side: 'top',
        align: 'center',
      },
    },
    {
      element: '#tour-nav-history',
      popover: {
        title: 'View Your History',
        description: 'This takes you to the History page. Let\'s go there next!',
        side: isMobile ? 'top' : 'right',
        align: 'center',
      },
    },
  ]
}

function getHistorySteps(isMobile: boolean): DriveStep[] {
  return [
    {
      element: '#tour-calendar',
      popover: {
        title: 'Your Calendar',
        description: 'Green dots mark days you wrote entries. Navigate between months using the arrows.',
        side: isMobile ? 'bottom' : 'right',
        align: 'center',
      },
    },
    {
      element: '#tour-entries-list',
      popover: {
        title: 'Your Past Entries',
        description: 'Tap any date on the calendar to see entries from that day. Tap an entry card to read the full content.',
        side: isMobile ? 'top' : 'left',
        align: 'center',
      },
    },
    {
      element: '#tour-nav-settings',
      popover: {
        title: 'Your Settings',
        description: 'Let\'s check out your settings next!',
        side: isMobile ? 'top' : 'right',
        align: 'center',
      },
    },
  ]
}

function getSettingsSteps(isMobile: boolean): DriveStep[] {
  return [
    {
      element: '#tour-edit-profile',
      popover: {
        title: 'Edit Your Profile',
        description: 'Tap the pencil icon to change your display name or profile photo.',
        side: isMobile ? 'bottom' : 'bottom',
        align: 'center',
      },
    },
    {
      element: '#tour-theme-switcher',
      popover: {
        title: 'Pick Your Theme',
        description: 'Switch between Light and Dark mode. Your choice is saved automatically.',
        side: isMobile ? 'top' : 'bottom',
        align: 'center',
      },
    },
  ]
}

export function useOnboardingTour() {
  const navigate = useNavigate()
  const driverRef = useRef<ReturnType<typeof driver> | null>(null)
  const [isTourActive, setIsTourActive] = useState(false)

  const startTour = useCallback(() => {
    const isMobile = window.innerWidth < 860
    setIsTourActive(true)

    const driverObj = driver({
      ...driverDefaults(),
      onDestroyStarted: () => {
        clearPendingTourStep()
        setIsTourActive(false)
        driverObj.destroy()
      },
      onNextClick: () => {
        const activeIndex = driverObj.getActiveIndex()
        const steps = driverObj.getConfig().steps || []

        // Last home step → navigate to /history
        if (activeIndex === steps.length - 1) {
          localStorage.setItem(TOUR_PENDING_KEY, 'history')
          setIsTourActive(false)
          driverObj.destroy()
          navigate('/history')
          return
        }

        driverObj.moveNext()
      },
      steps: getHomeSteps(isMobile),
    })

    driverRef.current = driverObj
    setTimeout(() => driverObj.drive(), 150)
  }, [navigate])

  const continueTourOnHistory = useCallback(() => {
    const isMobile = window.innerWidth < 860

    const driverObj = driver({
      ...driverDefaults(),
      onDestroyStarted: () => {
        clearPendingTourStep()
        driverObj.destroy()
      },
      onNextClick: () => {
        const activeIndex = driverObj.getActiveIndex()
        const steps = driverObj.getConfig().steps || []

        // Last history step → navigate to /settings
        if (activeIndex === steps.length - 1) {
          localStorage.setItem(TOUR_PENDING_KEY, 'settings')
          driverObj.destroy()
          navigate('/settings')
          return
        }

        driverObj.moveNext()
      },
      steps: getHistorySteps(isMobile),
    })

    driverRef.current = driverObj
    setTimeout(() => driverObj.drive(), 300)
  }, [navigate])

  const continueTourOnSettings = useCallback(() => {
    const isMobile = window.innerWidth < 860

    const driverObj = driver({
      ...driverDefaults(),
      onDestroyStarted: () => {
        clearPendingTourStep()
        driverObj.destroy()
      },
      onNextClick: () => {
        const activeIndex = driverObj.getActiveIndex()
        const steps = driverObj.getConfig().steps || []

        // Last settings step → navigate to /
        if (activeIndex === steps.length - 1) {
          clearPendingTourStep()
          driverObj.destroy()
          navigate('/write')
          return
        }

        driverObj.moveNext()
      },
      steps: getSettingsSteps(isMobile),
    })

    driverRef.current = driverObj
    setTimeout(() => driverObj.drive(), 300)
  }, [navigate])

  return { startTour, continueTourOnHistory, continueTourOnSettings, isTourActive }
}