{{/* Parameter Parsing */}}
{{ $usage := `lazyimg:
    Usage like:
    - {{ partial "lazyimg" "image.jpg" }}
    - {{ partial "lazyimg" (resources.Get "image.jpg") }}

    ...or more verbose by specifying a dict overriding the site.Params.lazyimg, e.g.:
    - {{ partial "lazyimg" (dict "resizer" "auto" "renderer" "lqip") }}
    - {{ partial "lazyimg" (dict "img" "image.jpg" "responsiveSizes" (slice "320px" "640px") "resizer" "responsive") }}

    Please ensure that image exists in ./assets directory.
` }}

{{/* Parse and normalize input parameters: */}}
{{ $params := merge site.Params.lazyimg (dict 
    "img" . 
    "resizer" (default "responsive" site.Params.lazyimg.resizer) 
    "renderer" (default "lqip" site.Params.lazyimg.renderer)
)}}
{{ if reflect.IsMap . }}
    {{ $userParams := dict }}
    {{/* Normalize by transforming all keys to lower-case: */}}
    {{ range $k, $v := . -}}
        {{ $userParams = $userParams | merge (dict (lower $k) $v) }}
    {{- end -}}
    {{ $params = merge $params $userParams }}
{{ end }}

{{/* Attempt to load image resource: */}}
{{ $resType := (printf "%T" $params.img) }}
{{ $resLoaded := in $resType "resource" }}
{{ if not $resLoaded }}
    {{ with $res := resources.Get $params.img }}
        {{ $params = merge $params (dict "img" $res) }}
        {{ $resLoaded = true }}
    {{ end }}
{{ end }}

{{/* Handle error if not loaded yet: */}}
{{ if not $resLoaded }}
    {{/* Try if error-handler is able to resolve it */}}
    {{ $params = partial (printf "error-handler/%s" site.Params.lazyimg.errorHandler) $params }}
    {{ if $params }}
        {{ $resLoaded = in (printf "%T" $params.img) "resource" }}
    {{ end }}
{{ end }}
{{/* Only proceed if resource has been loaded: */}}
{{ if $resLoaded }}
    {{/* Special handling for WebP renderers: */}}
    {{ if in $params.renderer "webp" }}
        {{/* Override user-supplied target format */}}
        {{ $resizeOptionsWebP := printf "%s webp" ($params.resizeoptions | replaceRE "(jpg|png|tif|bmp|gif)" "") }}
        {{ $paramsWebP := merge $params (dict "resizeoptions" $resizeOptionsWebP) }}
        {{ $imagesWebP := partial (printf "resizer/%s" $params.resizer) $paramsWebP }}
        {{ $imagesRegular := partial (printf "resizer/%s" $params.resizer) $params }}
        {{ partial (printf "renderer/%s" $params.renderer) (merge $params (dict "imgDict" $imagesWebP "imgDictFallback" $imagesRegular)) }}
    {{ else }}
        {{ $sizes := partial (printf "resizer/%s" $params.resizer) $params }}
        {{ partial (printf "renderer/%s" $params.renderer) (merge $params (dict "imgDict" $sizes)) }}
    {{ end }}
{{ end }}