package surf

import (
	"fmt"
	"net/http"
	"strings"

	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/lagoon/attach"
	"git.golem15.com/golem15/summercms/modules/pact"
	"gocloud.dev/blob"
	"gorm.io/gorm"
)

// uploadsPluginID owns the framework uploads route in the route table.
const uploadsPluginID = "summercms.surf"

// defaultUploadsPrefix matches the prefix attach.OpenBucket records when
// storage.uploads.public_path_prefix is empty.
const defaultUploadsPrefix = "/storage/uploads"

// mountUploads registers GET {storage.uploads.public_path_prefix}/{path...}
// when storage.uploads.serve is true. The handler delegates to
// attach.StaticHandlerPublic, so missing rows and is_public=false rows 404,
// and adds X-Content-Type-Options: nosniff because the files are served on
// the app origin. The bucket and the database are looked up per request:
// boot and route:list build the router before serve publishes either.
// The route owns the whole prefix: a plugin route at or under it fails
// BuildRouter, as a route under the admin prefix does. With the key false
// or absent nothing is registered and nothing is checked.
func mountUploads(r *Router, app *backpack.App) error {
	if r == nil || app == nil || app.Config == nil {
		return nil
	}
	if !app.Config.Bool("storage.uploads.serve") {
		return nil
	}
	prefix := strings.TrimSuffix(strings.TrimSpace(app.Config.String("storage.uploads.public_path_prefix")), "/")
	if prefix == "" {
		prefix = defaultUploadsPrefix
	}
	for _, rt := range r.routes {
		if rt.path == prefix || strings.HasPrefix(rt.path, prefix+"/") {
			return fmt.Errorf("surf: route %s %s (plugin %q) is under the uploads prefix storage.uploads.public_path_prefix %s, which storage.uploads.serve mounts", rt.method, rt.path, rt.pluginID, prefix)
		}
	}
	handler := uploadsHandler(app, prefix)
	r.BindPlugin(uploadsPluginID)
	r.GroupRaw(prefix, nil, func(g pact.Router) {
		g.Get("/{path...}", handler)
	})
	return nil
}

// uploadsHandler resolves the published bucket and database on every request
// and answers 404 while either is missing.
func uploadsHandler(app *backpack.App, prefix string) http.HandlerFunc {
	return func(w http.ResponseWriter, req *http.Request) {
		w.Header().Set("X-Content-Type-Options", "nosniff")
		bucket, ok := app.Lookup[*blob.Bucket]()
		if !ok || bucket == nil {
			http.NotFound(w, req)
			return
		}
		gdb, ok := app.Lookup[*gorm.DB]()
		if !ok || gdb == nil {
			http.NotFound(w, req)
			return
		}
		attach.StaticHandlerPublic(bucket, prefix, gdb).ServeHTTP(w, req)
	}
}