{{- $validFormats := slice "default" "terse" }}
{{- $validAlignments := slice "begin" "center" "end" }}

{{- $msg1 := "When passing a map to the internal pagination template, one of the elements must be named 'page', and it must be set to the context of the current page." }}
{{- $msg2 := "The 'format' specified in the map passed to the internal pagination template is invalid. Valid choices are: %s." }}
{{- $msg3 := "The 'align' specified in the map passed to the internal pagination template is invalid. Valid choices are: %s." }}

{{- $page := . }}
{{- $format := "default" }}
{{- $align := "begin" }}

{{- if reflect.IsMap . }}
  {{- with .page }}
    {{- $page = . }}
  {{- else }}
    {{- errorf $msg1 }}
  {{- end }}
  {{- with .format }}
    {{- $format = lower . }}
  {{- end }}
  {{- with .align }}
    {{- $align = lower . }}
  {{- end }}
{{- end }}

{{- $alignments := (dict "left" "" "center" "justify-content-center" "end" "justify-content-end") }}

{{- if not (in $validFormats $format) }}
    {{- errorf $msg2 (delimit $validFormats ", ") }}
{{- else if not (in $validFormats $format) }}
    {{- errorf $msg3 (delimit $validAlignments ", ") }}
{{- else }}
    {{- if gt $page.Paginator.TotalPages 1 }}
    <ul class="pagination {{ index $alignments $align }} pagination-{{ $format }}">
      {{- partial (printf "partials/pagination/%s" $format) $page }}
    </ul>
  {{- end }}
{{- end -}}

{{/* Format: default
{{/* --------------------------------------------------------------------- */}}
{{- define "partials/pagination/default" }}
  {{- with .Paginator }}
    {{- $currentPageNumber := .PageNumber }}

    {{- with .First }}
      {{- if ne $currentPageNumber .PageNumber }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="First" class="page-link" role="button"><span aria-hidden="true">&laquo;&laquo;</span></a>
      </li>
      {{- else }}
      <li class="page-item disabled">
        <a aria-disabled="true" aria-label="First" class="page-link" role="button" tabindex="-1"><span aria-hidden="true">&laquo;&laquo;</span></a>
      </li>
      {{- end }}
    {{- end }}

    {{- with .Prev }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="Previous" class="page-link" role="button"><span aria-hidden="true">&laquo;</span></a>
      </li>
    {{- else }}
      <li class="page-item disabled">
        <a aria-disabled="true" aria-label="Previous" class="page-link" role="button" tabindex="-1"><span aria-hidden="true">&laquo;</span></a>
      </li>
    {{- end }}

    {{- $slots := 5 }}
    {{- $start := math.Max 1 (sub .PageNumber (math.Floor (div $slots 2))) }}
    {{- $end := math.Min .TotalPages (sub (add $start $slots) 1) }}
    {{- if lt (add (sub $end $start) 1) $slots }}
      {{- $start = math.Max 1 (add (sub $end $slots) 1) }}
    {{- end }}

    {{- range $k := seq $start $end }}
      {{- if eq $.Paginator.PageNumber $k }}
      <li class="page-item active">
        <a aria-current="page" aria-label="Page {{ $k }}" class="page-link" role="button">{{ $k }}</a>
      </li>
      {{- else }}
      <li class="page-item">
        <a href="{{ (index $.Paginator.Pagers (sub $k 1)).URL }}" aria-label="Page {{ $k }}" class="page-link" role="button">{{ $k }}</a>
      </li>
      {{- end }}
    {{- end }}

    {{- with .Next }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="Next" class="page-link" role="button"><span aria-hidden="true">&raquo;</span></a>
      </li>
    {{- else }}
      <li class="page-item disabled">
        <a aria-disabled="true" aria-label="Next" class="page-link" role="button" tabindex="-1"><span aria-hidden="true">&raquo;</span></a>
      </li>
    {{- end }}

    {{- with .Last }}
      {{- if ne $currentPageNumber .PageNumber }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="Last" class="page-link" role="button"><span aria-hidden="true">&raquo;&raquo;</span></a>
      </li>
      {{- else }}
      <li class="page-item disabled">
        <a aria-disabled="true" aria-label="Last" class="page-link" role="button" tabindex="-1"><span aria-hidden="true">&raquo;&raquo;</span></a>
      </li>
      {{- end }}
    {{- end }}
  {{- end }}
{{- end -}}

{{/* Format: terse
{{/* --------------------------------------------------------------------- */}}
{{- define "partials/pagination/terse" }}
  {{- with .Paginator }}
    {{- $currentPageNumber := .PageNumber }}

    {{- with .First }}
      {{- if ne $currentPageNumber .PageNumber }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="First" class="page-link" role="button"><span aria-hidden="true">&laquo;&laquo;</span></a>
      </li>
      {{- end }}
    {{- end }}

    {{- with .Prev }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="Previous" class="page-link" role="button"><span aria-hidden="true">&laquo;</span></a>
      </li>
    {{- end }}

    {{- $slots := 3 }}
    {{- $start := math.Max 1 (sub .PageNumber (math.Floor (div $slots 2))) }}
    {{- $end := math.Min .TotalPages (sub (add $start $slots) 1) }}
    {{- if lt (add (sub $end $start) 1) $slots }}
      {{- $start = math.Max 1 (add (sub $end $slots) 1) }}
    {{- end }}

    {{- range $k := seq $start $end }}
      {{- if eq $.Paginator.PageNumber $k }}
      <li class="page-item active">
        <a aria-current="page" aria-label="Page {{ $k }}" class="page-link" role="button">{{ $k }}</a>
      </li>
      {{- else }}
      <li class="page-item">
        <a href="{{ (index $.Paginator.Pagers (sub $k 1)).URL }}" aria-label="Page {{ $k }}" class="page-link" role="button">{{ $k }}</a>
      </li>
      {{- end }}
    {{- end }}

    {{- with .Next }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="Next" class="page-link" role="button"><span aria-hidden="true">&raquo;</span></a>
      </li>
    {{- end }}

    {{- with .Last }}
      {{- if ne $currentPageNumber .PageNumber }}
      <li class="page-item">
        <a href="{{ .URL }}" aria-label="Last" class="page-link" role="button"><span aria-hidden="true">&raquo;&raquo;</span></a>
      </li>
      {{- end }}
    {{- end }}
  {{- end }}
{{- end -}}