import { useEffect, useState } from 'react'
import { ArrowRightIcon, SearchIcon } from '@primer/octicons-react'
import { Text } from '@primer/react'

import { useProductLandingContext } from 'components/context/ProductLandingContext'
import { useTranslation } from 'components/hooks/useTranslation'
import { CodeExampleCard } from 'components/landing/CodeExampleCard'
import { Link } from 'components/Link'

const PAGE_SIZE = 6
export const CodeExamples = () => {
  const { productCodeExamples } = useProductLandingContext()
  const { t } = useTranslation('product_landing')
  const [numVisible, setNumVisible] = useState(PAGE_SIZE)
  const [search, setSearch] = useState('')
  const [typed, setTyped] = useState('')

  useEffect(() => {
    setNumVisible(PAGE_SIZE) // reset the visible count (only matters after searching)
  }, [search])

  const isSearching = !!search
  let searchResults: typeof productCodeExamples = []
  if (isSearching) {
    // The following replace method escapes special characters in regular expression creation.
    const matchReg = new RegExp(search.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, '\\$&'), 'i')
    searchResults = productCodeExamples.filter((example) => {
      const searchableStr = `${example.tags.join(' ')} ${example.title} ${example.description}`
      return matchReg.test(searchableStr)
    })
  }

  return (
    <div>
      <form
        className="pr-lg-3 mb-5 mt-3"
        onSubmit={(event) => {
          event.preventDefault()
          setSearch(typed.trim())
        }}
      >
        <Text
          className="ml-1 mr-2"
          fontWeight="bold"
          fontSize={2}
          as="label"
          htmlFor="searchCodeExamples"
          id="searchCodeExamples"
        >
          Search code examples:
        </Text>
        <input
          data-testid="code-examples-input"
          className="input-lg py-2 px-3 col-12 col-lg-8 form-control"
          placeholder={t('search_code_examples')}
          type="search"
          autoComplete="off"
          aria-label={t('search_code_examples')}
          onChange={(event) => setTyped(event.target.value)}
          value={typed}
        />
        <button data-testid="code-examples-search-btn" className="btn ml-2 py-2" type="submit">
          Search
        </button>
      </form>

      {isSearching && (
        <div role="status">
          <h3>
            {t('search_results_for')}: {search}
          </h3>
          <p className="mb-4">
            {t('matches_displayed')}: {searchResults.length}
          </p>
        </div>
      )}
      <ul className="d-flex flex-wrap gutter">
        {(isSearching ? searchResults : productCodeExamples.slice(0, numVisible)).map((example) => {
          return (
            <li key={example.href} className="col-12 col-xl-4 col-lg-6 mb-4 list-style-none">
              <CodeExampleCard example={example} />
            </li>
          )
        })}
      </ul>

      {numVisible < productCodeExamples.length && !isSearching && (
        <button
          data-testid="code-examples-show-more"
          className="btn btn-outline float-right"
          onClick={() => setNumVisible(numVisible + PAGE_SIZE)}
        >
          {t('show_more')} <ArrowRightIcon />
        </button>
      )}

      {isSearching && searchResults.length === 0 && (
        <div
          role="status"
          data-testid="code-examples-no-results"
          className="py-4 text-center color-fg-muted"
        >
          <div className="mb-3">
            <SearchIcon size={24} />{' '}
          </div>
          <h3 className="text-normal">
            {t('sorry')} <strong>{search}</strong>
          </h3>
          <p className="my-3 f4">
            {t('no_example')} <br /> {t('try_another')}
          </p>
          <Link href="https://github.com/github/docs/tree/main/data/product-examples">
            {t('learn')} <ArrowRightIcon />
          </Link>
        </div>
      )}
    </div>
  )
}