import React, {useState, useEffect, useMemo, useRef} from 'react'
import {DateTime} from 'luxon'
import axios from 'axios'
import Link from 'next/link'

import {Button} from '@rmwc/button'
import ActionBar from '~/components/admin/actionBar'
import {Icon} from '@rmwc/icon'

import styles from '~/styles/imageGallery.module.css'

EditImages.getInitialProps = async ({ctx: {axios, query: {slug}}}) => {
  const {data: item} = await axios.get(`/api/items/by-slug/${slug}`)
  return {item}
}

export default function EditImages({item: _item}) {
  const [item, setItem] = useState(_item)
  const fileRef = useRef()

  // Only re-sort images whenever item changes
  const images = useMemo(() => item.images.slice(0).sort(
    (a,b) => DateTime.fromISO(a.date_uploaded).diff(DateTime.fromISO(b.date_uploaded))
  ), [item])


  async function selectImage(ev){
    if(ev) ev.preventDefault()

    fileRef.current.click()
  }

  useEffect(()=>{
    fileRef.current.addEventListener('change', uploadImage)
    return ()=>fileRef.current.removeEventListener('change', uploadImage)
  }, [])

  async function uploadImage(ev){
    if(ev) ev.preventDefault()

    const image = await readFileAsync(ev.target)
    const {data: updatedItem} = await axios.post(`/api/items/${item.uuid}/images`, {image})
    setItem(updatedItem)
  }

  function handleSetFeatured(image){
    return async (ev) => {
      if(ev) ev.preventDefault();

      const {data: updatedItem} = await axios.post(`/api/images/${image.uuid}/featured`)
      setItem(updatedItem)
    }
  }

  function handleRemoveImage(image){
    return async (ev) => {
      if(ev) ev.preventDefault()

      const {data: updatedItem} = await axios.delete(`/api/images/${image.uuid}`)
      setItem(updatedItem)
    }
  }

  return (
    <>
      <ActionBar title={`Editing images for "${item.name}"`}>
        <Button outlined onClick={selectImage}>Add Image</Button>
      </ActionBar>
      <Link href={`/admin/items/${item.urlslug}`}><a><Button icon="arrow_left">Back to {item.name}</Button></a></Link>
      <div className={styles.gallery}>
        {images.map(image => (
          <div key={image.uuid} className={styles.image}>
            <img key={image.uuid} src={`/api/images/${image.uuid}/thumb`}/>
            <div className={styles.details}>
              <div>
                <span>Uploaded {DateTime.fromISO(image.date_uploaded).toFormat('DD')}</span>
                <span>by {image.uploader.email}</span>
              </div>
              <button title="Set Featured" onClick={handleSetFeatured(image)} className="buttonLink"><Icon icon={image.featured?"star":"star_outline"}/></button>
              <button title="Remove Image" onClick={handleRemoveImage(image)} className="buttonLink"><Icon icon="delete"/></button>
            </div>
          </div>
        ))}
        {!images.length ? (
          <>
            <p style={{marginTop: '100px'}}>No images added for this item.</p>
            <Button outlined onClick={selectImage}>Add One!</Button>
          </>
        ) : (
          <p><Button outlined onClick={selectImage}>Add Image</Button></p>
        )}
      </div>
      <input ref={fileRef} className={styles.upload} type="file" accept="image/*" />
    </>
  )
}

function readFileAsync(fileInput){
  const reader = new FileReader()

  return new Promise((resolve, reject) => {
    reader.addEventListener('load', () => {
      resolve(reader.result)
    })

    reader.addEventListener('error', reject)
    reader.addEventListener('abort', reject)

    reader.readAsDataURL(fileInput.files[0])
  })
}