import Link from 'next/link'
import {
  documents,
  authors,
  topics as topicsList,
  affiliations,
} from './db/data'
import { epoch2datestring } from './utils/epoch2datestring'
import { Fragment } from 'react'

export default function Home() {
  const RandomDocs = (): React.ReactNode[] => {
    // Convert the object keys into an array
    const keys = Object.keys(documents)

    // Determine the number of keys to process (all if fewer than 10)
    const numKeysToProcess = keys.length < 10 ? keys.length : 10

    // Shuffle the keys array if there are more than 10 keys
    if (keys.length > 10) {
      for (let i = keys.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1))
        ;[keys[i], keys[j]] = [keys[j], keys[i]]
      }
    }

    // Select keys based on numKeysToProcess
    const selectedKeys = keys.slice(0, numKeysToProcess)

    // Iterate over each of the selected keys
    return selectedKeys.map((key, index) => {
      const { title, dates, type, topics } = documents[key].manifest
      let dateString = epoch2datestring(dates[dates.length - 1])
      let typeString = ''
      switch (type) {
        case 'report':
          typeString = 'report'
          break
        case 'presentation':
          typeString = 'presentation'
          break
        case 'white paper':
          typeString = 'white paper'
          break
        case 'datasheet':
          typeString = 'datasheet'
          break
        case 'dwm':
          typeString = 'DWM'
          break
        case 'other':
          typeString = 'document'
          break
      }

      const randomFromArray = (arr: string[]): string =>
        arr[Math.floor(Math.random() * arr.length)]

      return (
        <div key={index}>
          <Link href={`/document/view/${key}`}>{title}</Link>, a {typeString}{' '}
          about {topicsList[randomFromArray(topics)]['name']} published on{' '}
          {dateString}
          .
          <br />
        </div>
      )
    })
  }

  const AuthorDisplay = () => {
    return Object.entries(authors).map(([author, data], index) => {
      let affiliationSlug = data.affiliation[0].split('@')[1]
      let affiliation = affiliations[affiliationSlug]
      return (
        <div key={index}>
          <Link href={`/author/${author}`}>
            {data.name.first}
            {data.name.nickname ? ` "${data.name.nickname}" ` : ' '}
            {data.name.last}
          </Link>{' '}
          of{' '}
          <Link href={`/affiliation/${affiliationSlug}`}>
            {affiliation.short}
          </Link>
        </div>
      )
    })
  }

  return (
    <div className='content text-slate-800 flex flex-wrap'>
      <p className='font-serif text-lg max-w-lg'>
        eeXiv<sup>2</sup> is a free distribution service and an open-access
        archive for nearly 2.4 million scholarly articles in the fields of
        physics, mathematics, computer science, quantitative biology,
        quantitative finance, statistics, electrical engineering and systems
        science, and economics. Materials on this site may be published
        independently through other channels.
      </p>
      <div className='bg-slate-800 rounded-lg p-6 w-full lg:max-w-lg md:max-w-md my-4 lg:my-0'>
        <span className='text-3xl md:text-4xl text-slate-200'>eeXiv News</span>
        <br className='my-2' />
        <span className='text-xl text-slate-400'>
          Stay up to date with what is happening at eeXiv.
        </span>
        <br className='my-2' />
        <span className='text-lg text-slate-200'>Latest news</span>
        <br className='my-4' />
        <div className='text-slate-50'>
          - eeXiv is currently under active development!
        </div>
      </div>
      <div className='grid grid-cols-1 space-y-2 mt-4'>
        <hr className='mx-auto w-full h-1 border-0 bg-slate-200 my-2 rounded-md' />
        <span className='font-serif text-xl'>
          Selected documents in various disciplines
        </span>
        <RandomDocs />
        <hr className='mx-auto w-full h-1 border-0 bg-slate-200 my-2 rounded-md' />
        <span className='font-serif text-xl'>
          Our esteemed faculty and alumni
        </span>
        <AuthorDisplay />
      </div>
    </div>
  )
}