// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

package http

import (
	"context"
	"fmt"
	"io"
	"mime"
	"net/http"
	"path/filepath"
	"strconv"
	"strings"

	"github.com/blang/semver/v4"
	"github.com/julienschmidt/httprouter"

	"github.com/siderolabs/image-service/internal/profile"
)

// handleImage handles downloading of boot assets.
func (f *Frontend) handleImage(ctx context.Context, w http.ResponseWriter, r *http.Request, p httprouter.Params) error {
	configurationID := p.ByName("configuration")

	configuration, err := f.configService.Get(ctx, configurationID)
	if err != nil {
		return err
	}

	versionTag := p.ByName("version")
	if !strings.HasPrefix(versionTag, "v") {
		versionTag = "v" + versionTag
	}

	version, err := semver.Parse(versionTag[1:])
	if err != nil {
		return fmt.Errorf("error parsing version: %w", err)
	}

	path := p.ByName("path")

	prof, err := profile.ParseFromPath(path)
	if err != nil {
		return fmt.Errorf("error parsing profile from path: %w", err)
	}

	prof, err = profile.EnhanceFromConfiguration(prof, configuration, versionTag)
	if err != nil {
		return fmt.Errorf("error enhancing profile from configuration: %w", err)
	}

	if err = prof.Validate(); err != nil {
		return fmt.Errorf("error validating profile: %w", err)
	}

	asset, err := f.assetBuilder.Build(ctx, prof, version.String())
	if err != nil {
		return err
	}

	defer asset.Release() //nolint:errcheck

	w.Header().Set("Content-Length", strconv.FormatInt(asset.Size(), 10))

	if ext := filepath.Ext(path); ext != "" {
		w.Header().Set("Content-Type", mime.TypeByExtension(ext))
	}

	w.WriteHeader(http.StatusOK)

	if r.Method == http.MethodHead {
		return nil
	}

	reader, err := asset.Reader()
	if err != nil {
		return err
	}

	defer reader.Close() //nolint:errcheck

	_, err = io.Copy(w, reader)

	return err
}