// cloudHandler returns a handler that responds with the cloud config for the
// requester.
func cloudHandler(srv server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		group, err := groupFromContext(ctx)
		if err != nil || group.Profile == "" {
			http.NotFound(w, req)
			return
		}
		profile, err := srv.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil || profile.CloudId == "" {
			http.NotFound(w, req)
			return
		}
		contents, err := srv.CloudGet(ctx, profile.CloudId)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		// collect data for rendering
		data := make(map[string]interface{})
		if group.Metadata != nil {
			err = json.Unmarshal(group.Metadata, &data)
			if err != nil {
				log.Errorf("error unmarshalling metadata: %v", err)
				http.NotFound(w, req)
				return
			}
		}
		for key, value := range group.Selector {
			data[strings.ToLower(key)] = value
		}

		// render the template of a cloud config with data
		var buf bytes.Buffer
		err = renderTemplate(&buf, data, contents)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		config := buf.String()
		if !cloudinit.IsCloudConfig(config) && !cloudinit.IsScript(config) {
			log.Error("error parsing user-data")
			http.NotFound(w, req)
			return
		}

		if cloudinit.IsCloudConfig(config) {
			if _, err = cloudinit.NewCloudConfig(config); err != nil {
				log.Errorf("error parsing cloud config: %v", err)
				http.NotFound(w, req)
				return
			}
		}
		http.ServeContent(w, req, "", time.Time{}, strings.NewReader(config))
	}
	return ContextHandlerFunc(fn)
}

// selectProfile selects the Profile for the given query parameters, adds the
// Profile to the ctx, and calls the next handler. The next handler should
// handle a missing profile.
func (s *Server) selectProfile(core server.Server, next ContextHandler) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		attrs := labelsFromRequest(s.logger, req)
		// match machine request
		profile, err := core.SelectProfile(ctx, &pb.SelectProfileRequest{Labels: attrs})
		if err == nil {
			// add the Profile to the ctx for the next handler
			ctx = withProfile(ctx, profile)
		}
		next.ServeHTTP(ctx, w, req)
	}
	return ContextHandlerFunc(fn)
}

// selectGroup selects the Group whose selectors match the query parameters,
// adds the Group to the ctx, and calls the next handler. The next handler
// should handle a missing Group.
func selectGroup(srv server.Server, next ContextHandler) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		attrs := labelsFromRequest(req)
		// match machine request
		group, err := srv.SelectGroup(ctx, &pb.SelectGroupRequest{Labels: attrs})
		if err == nil {
			// add the Group to the ctx for next handler
			ctx = withGroup(ctx, group)
		}
		next.ServeHTTP(ctx, w, req)
	}
	return ContextHandlerFunc(fn)
}

// genericHandler returns a handler that responds with generic file for
// the requester.
func genericHandler(srv server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		group, err := groupFromContext(ctx)
		if err != nil || group.Profile == "" {
			http.NotFound(w, req)
			return
		}
		profile, err := srv.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil || profile.GenericId == "" {
			http.NotFound(w, req)
			return
		}
		contents, err := srv.GenericGet(ctx, profile.GenericId)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		// collect data for rendering
		data := make(map[string]interface{})
		if group.Metadata != nil {
			err = json.Unmarshal(group.Metadata, &data)
			if err != nil {
				log.Errorf("error unmarshalling metadata: %v", err)
				http.NotFound(w, req)
				return
			}
		}
		data["query"] = req.URL.RawQuery
		for key, value := range group.Selector {
			data[strings.ToLower(key)] = value
		}

		// render the template of a generic config with data
		var buf bytes.Buffer
		err = renderTemplate(&buf, data, contents)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		config := buf.String()
		http.ServeContent(w, req, "", time.Time{}, strings.NewReader(config))
	}
	return ContextHandlerFunc(fn)
}

// pixiecoreHandler returns a handler that renders the boot config JSON for
// the requester, to implement the Pixiecore API specification.
// https://github.com/danderson/pixiecore/blob/master/README.api.md
func (s *Server) pixiecoreHandler(core server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		// pixiecore only provides a MAC address label
		macAddr, err := parseMAC(filepath.Base(req.URL.Path))
		if err != nil {
			s.logger.Errorf("unparseable MAC address: %v", err)
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		attrs := map[string]string{"mac": macAddr.String()}

		group, err := core.SelectGroup(ctx, &pb.SelectGroupRequest{Labels: attrs})
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"label": macAddr,
			}).Infof("No matching group")
			http.NotFound(w, req)
			return
		}

		profile, err := core.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"label": macAddr,
				"group": group.Id,
			}).Infof("No profile named: %s", group.Profile)
			http.NotFound(w, req)
			return
		}

		// match was successful
		s.logger.WithFields(logrus.Fields{
			"label":   macAddr,
			"group":   group.Id,
			"profile": profile.Id,
		}).Debug("Matched a Pixiecore config")

		s.renderJSON(w, profile.Boot)
	}
	return ContextHandlerFunc(fn)
}

// pixiecoreHandler returns a handler that renders the boot config JSON for
// the requester, to implement the Pixiecore API specification.
// https://github.com/danderson/pixiecore/blob/master/README.api.md
func pixiecoreHandler(srv server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		macAddr, err := parseMAC(filepath.Base(req.URL.Path))
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}
		// pixiecore only provides MAC addresses
		attrs := map[string]string{"mac": macAddr.String()}
		group, err := srv.SelectGroup(ctx, &pb.SelectGroupRequest{Labels: attrs})
		if err != nil {
			http.NotFound(w, req)
			return
		}
		profile, err := srv.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil {
			http.NotFound(w, req)
			return
		}
		renderJSON(w, profile.Boot)
	}
	return ContextHandlerFunc(fn)
}

// ignitionHandler returns a handler that responds with the Ignition config
// for the requester. The Ignition file referenced in the Profile is parsed
// as raw Ignition (for .ign/.ignition) or rendered to a Fuze config (YAML)
// and converted to Ignition. Ignition configs are served as HTTP JSON
// responses.
func (s *Server) ignitionHandler(core server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		group, err := groupFromContext(ctx)
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"labels": labelsFromRequest(nil, req),
			}).Infof("No matching group")
			http.NotFound(w, req)
			return
		}

		profile, err := core.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"labels":     labelsFromRequest(nil, req),
				"group":      group.Id,
				"group_name": group.Name,
			}).Infof("No profile named: %s", group.Profile)
			http.NotFound(w, req)
			return
		}

		contents, err := core.IgnitionGet(ctx, profile.IgnitionId)
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"labels":     labelsFromRequest(nil, req),
				"group":      group.Id,
				"group_name": group.Name,
				"profile":    group.Profile,
			}).Infof("No Ignition or Fuze template named: %s", profile.IgnitionId)
			http.NotFound(w, req)
			return
		}

		// match was successful
		s.logger.WithFields(logrus.Fields{
			"labels":  labelsFromRequest(nil, req),
			"group":   group.Id,
			"profile": profile.Id,
		}).Debug("Matched an Ignition or Fuze template")

		// Skip rendering if raw Ignition JSON is provided
		if isIgnition(profile.IgnitionId) {
			_, err := ignition.Parse([]byte(contents))
			if err != nil {
				s.logger.Warningf("warning parsing Ignition JSON: %v", err)
			}
			s.writeJSON(w, []byte(contents))
			return
		}

		// Fuze Config template

		// collect data for rendering
		data := make(map[string]interface{})
		if group.Metadata != nil {
			err = json.Unmarshal(group.Metadata, &data)
			if err != nil {
				s.logger.Errorf("error unmarshalling metadata: %v", err)
				http.NotFound(w, req)
				return
			}
		}
		data["query"] = req.URL.RawQuery
		for key, value := range group.Selector {
			data[strings.ToLower(key)] = value
		}

		// render the template for an Ignition config with data
		var buf bytes.Buffer
		err = s.renderTemplate(&buf, data, contents)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		// Parse fuze config into an Ignition config
		config, err := fuze.ParseAsV2_0_0(buf.Bytes())
		if err == nil {
			s.renderJSON(w, config)
			return
		}

		s.logger.Errorf("error parsing Ignition config: %v", err)
		http.NotFound(w, req)
		return
	}
	return ContextHandlerFunc(fn)
}

// ignitionHandler returns a handler that responds with the Ignition config
// for the requester. The Ignition file referenced in the Profile is rendered
// with metadata and parsed and validated as either YAML or JSON based on the
// extension. The Ignition config is served as an HTTP JSON response.
func ignitionHandler(srv server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		group, err := groupFromContext(ctx)
		if err != nil || group.Profile == "" {
			http.NotFound(w, req)
			return
		}
		profile, err := srv.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil || profile.IgnitionId == "" {
			http.NotFound(w, req)
			return
		}
		contents, err := srv.IgnitionGet(ctx, profile.IgnitionId)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		// collect data for rendering Ignition Config
		data := make(map[string]interface{})
		if group.Metadata != nil {
			err = json.Unmarshal(group.Metadata, &data)
			if err != nil {
				log.Errorf("error unmarshalling metadata: %v", err)
				http.NotFound(w, req)
				return
			}
		}
		data["query"] = req.URL.RawQuery
		for key, value := range group.Selector {
			data[strings.ToLower(key)] = value
		}

		// render the template for an Ignition config with data
		var buf bytes.Buffer
		err = renderTemplate(&buf, data, contents)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		// Unmarshal YAML or JSON to Ignition V2
		cfg, err := parseToV2(buf.Bytes())
		if err == nil {
			renderJSON(w, cfg)
			return
		}

		// Unmarshal YAML or JSON to Ignition V1
		oldCfg, err := parseToV1(buf.Bytes())
		if err == nil {
			renderJSON(w, oldCfg)
			return
		}

		log.Errorf("error parsing Ignition config: %v", err)
		http.NotFound(w, req)
		return
	}
	return ContextHandlerFunc(fn)
}

// genericHandler returns a handler that responds with generic file for
// the requester.
func (s *Server) genericHandler(core server.Server) ContextHandler {
	fn := func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
		group, err := groupFromContext(ctx)
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"labels": labelsFromRequest(nil, req),
			}).Infof("No matching group")
			http.NotFound(w, req)
			return
		}
		profile, err := core.ProfileGet(ctx, &pb.ProfileGetRequest{Id: group.Profile})
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"labels":     labelsFromRequest(nil, req),
				"group":      group.Id,
				"group_name": group.Name,
			}).Infof("No profile named: %s", group.Profile)
			http.NotFound(w, req)
			return
		}
		contents, err := core.GenericGet(ctx, profile.GenericId)
		if err != nil {
			s.logger.WithFields(logrus.Fields{
				"labels":     labelsFromRequest(nil, req),
				"group":      group.Id,
				"group_name": group.Name,
				"profile":    group.Profile,
			}).Infof("No generic template named: %s", profile.GenericId)
			http.NotFound(w, req)
			return
		}

		// match was successful
		s.logger.WithFields(logrus.Fields{
			"labels":  labelsFromRequest(nil, req),
			"group":   group.Id,
			"profile": profile.Id,
		}).Debug("Matched a generic template")

		// collect data for rendering
		data := make(map[string]interface{})
		if group.Metadata != nil {
			err = json.Unmarshal(group.Metadata, &data)
			if err != nil {
				s.logger.Errorf("error unmarshalling metadata: %v", err)
				http.NotFound(w, req)
				return
			}
		}
		data["query"] = req.URL.RawQuery
		for key, value := range group.Selector {
			data[strings.ToLower(key)] = value
		}

		// render the template of a generic config with data
		var buf bytes.Buffer
		err = s.renderTemplate(&buf, data, contents)
		if err != nil {
			http.NotFound(w, req)
			return
		}

		config := buf.String()
		http.ServeContent(w, req, "", time.Time{}, strings.NewReader(config))
	}
	return ContextHandlerFunc(fn)
}