package web

import (
	"io/fs"
	"net/http"
	"path"
	"strings"

	"khosra/internal/content"
)

// serveAsset answers a file that lives inside a bundle's own directory, reporting whether it handled the
// request.
//
// This is how a relative `src` in a body actually resolves: a page at /art/monsoon/ links `10-first.jpg`,
// the browser asks for /art/monsoon/10-first.jpg, and the bytes come from that bundle's directory.
//
// The bundle is looked up *first*, and the file is only then read from the directory that bundle owns — never
// from a path assembled out of the request. That ordering is what ADR-0024 requires: every byte inside a
// bundle inherits the bundle's publish status, so no route may serve bundle bytes by path alone. When drafts
// arrive (queue 19) the filter belongs here, beside the lookup, and nowhere else.
func serveAsset(w http.ResponseWriter, req *http.Request, site *content.Site, siteFS fs.FS, res resolution) bool {
	if siteFS == nil {
		return false
	}
	dir, file := path.Split(res.key)
	route := strings.TrimSuffix(dir, "/")
	switch {
	case route == "" || file == "":
		return false
	case strings.Contains(file, "/") || file == "." || file == "..":
		return false
	case strings.HasSuffix(strings.ToLower(file), ".md"):
		// A .md inside a bundle is content or a fragment, never an asset. Serving it raw would publish the
		// partials an author never addressed (content-model.md).
		return false
	}
	key, live := site.KeyFor(route)
	if !live {
		return false
	}
	b, _, found := site.Lookup(key, res.lang)
	if !found {
		return false
	}
	assets, hasAssets := b.Assets()
	if !hasAssets {
		return false
	}
	name := path.Join(assets, file)
	if info, err := fs.Stat(siteFS, name); err != nil || info.IsDir() {
		return false
	}
	// ServeFileFS handles the content type, conditional requests and ranges — an image wants all three, and
	// none of them is this engine's business to reimplement.
	http.ServeFileFS(w, req, siteFS, name)
	return true
}