---
import { themeConfig } from '@/config'
---

<a href="/" class="back-button">
  <svg width="16" height="16" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg">
    <path
      d="M2.5 6.5H9.5C11.1569 6.5 12.5 7.84315 12.5 9.5V9.5C12.5 11.1569 11.1569 12.5 9.5 12.5H7.5M2.5 6.5L5.5 9.5M2.5 6.5L5.5 3.5"
      stroke="currentColor"
      stroke-width="1.25"
      stroke-linecap="round"
      stroke-linejoin="round"></path>
  </svg>
  index
</a>

<script
  is:inline
  define:vars={{
    contentWidth: themeConfig.general.contentWidth,
    centeredLayout: themeConfig.general.centeredLayout,
    toc: themeConfig.post.toc
  }}
>
  ;(function () {
    // Adjust back button position based on layout and screen size
    function adjustBackButtonPosition() {
      const button = document.querySelector('.back-button')
      if (!button) return

      // If not using centered layout, remove fixed positioning
      if (!centeredLayout) {
        button.classList.remove('fixed-position')
        button.style.left = ''
        return
      }

      // Calculate available margin space for positioning
      const pageWidth = window.innerWidth
      const contentWidthValue = parseFloat(contentWidth)
      // Apply the same minimum width logic as in BaseLayout
      const widthValue = Math.min(contentWidthValue, 50)
      const shouldUseCustomWidth = widthValue > 25
      const finalWidthValue = shouldUseCustomWidth ? widthValue : 25
      const margin = (pageWidth - finalWidthValue * 16) / 2
      const baseMinSpace = 11 * 16 // Base minimum space needed
      // If toc is enabled, need additional 2.5rem (40px) space
      const minSpace = toc ? baseMinSpace + 52 : baseMinSpace + 12

      // Position button fixed on the left if there's enough space
      if (margin >= minSpace) {
        button.classList.add('fixed-position')
        const basePosition = margin - baseMinSpace
        // If toc is enabled, move 2.5rem (40px) further left
        const leftPosition = toc ? basePosition - 40 : basePosition
        button.style.left = `${leftPosition}px`
      } else {
        button.classList.remove('fixed-position')
        button.style.left = ''
      }
    }

    adjustBackButtonPosition()

    // Use only astro:page-load as it fires on initial load and navigation
    document.addEventListener('astro:page-load', adjustBackButtonPosition)
    window.addEventListener('resize', adjustBackButtonPosition)
  })()
</script>

<style>
  .back-button {
    width: 8rem;
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    font-family: var(--serif);
    font-size: var(--font-size-m);
    font-style: italic;
    letter-spacing: 0;
    line-height: 1.75;
    color: var(--text-secondary);
    cursor: pointer;
    border: none;
    background-color: transparent;
    position: relative;
    margin-bottom: 2.5em;
    padding: 0;
    left: -0.175em;
    transition: color 0.2s ease-out;
    text-decoration: none;
  }

  .back-button:hover {
    color: var(--text-primary);
  }

  @media (hover: none) and (pointer: coarse) {
    .back-button:hover {
      color: var(--text-secondary);
    }
  }

  .back-button svg {
    width: 0.8rem;
    height: 0.8rem;
    flex-shrink: 0;
  }

  .back-button.fixed-position {
    position: fixed;
    top: 6rem;
    margin-bottom: 0;
    padding-left: 0.75rem;
    z-index: 10;
  }
</style>