// Copyright (c) 2021 Gitpod GmbH. All rights reserved.
// Licensed under the GNU Affero General Public License (AGPL).
// See License.AGPL.txt in the project root for license information.

package cmd

import (
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"

	_ "embed"

	"github.com/gitpod-io/gitpod/common-go/log"
	"github.com/gitpod-io/gitpod/installer/pkg/common"
	"github.com/gitpod-io/gitpod/installer/pkg/components"
	"github.com/gitpod-io/gitpod/installer/pkg/config"
	configv1 "github.com/gitpod-io/gitpod/installer/pkg/config/v1"
	"github.com/gitpod-io/gitpod/installer/pkg/config/v1/experimental"
	"github.com/gitpod-io/gitpod/installer/pkg/postprocess"
	"github.com/spf13/cobra"
	"sigs.k8s.io/yaml"
)

var renderOpts struct {
	ConfigFN               string
	Namespace              string
	ValidateConfigDisabled bool
	UseExperimentalConfig  bool
	FilesDir               string
}

// renderCmd represents the render command
var renderCmd = &cobra.Command{
	Use:   "render",
	Short: "Renders the Kubernetes manifests required to install Gitpod",
	Long: `Renders the Kubernetes manifests required to install Gitpod

A config file is required which can be generated with the init command.`,
	Example: `  # Default install.
  gitpod-installer render --config config.yaml | kubectl apply -f -

  # Install Gitpod into a non-default namespace.
  gitpod-installer render --config config.yaml --namespace gitpod | kubectl apply -f -`,
	RunE: func(cmd *cobra.Command, args []string) error {
		yaml, err := renderFn()
		if err != nil {
			return err
		}

		if renderOpts.FilesDir != "" {
			err := saveYamlToFiles(renderOpts.FilesDir, yaml)
			if err != nil {
				return err
			}
			return nil
		}

		for _, item := range yaml {
			fmt.Println(item)
		}

		return nil
	},
}

func renderFn() ([]string, error) {
	_, cfgVersion, cfg, err := loadConfig(renderOpts.ConfigFN)
	if err != nil {
		return nil, err
	}

	if cfg.Experimental != nil {
		if renderOpts.UseExperimentalConfig {
			fmt.Fprintf(os.Stderr, "rendering using experimental config\n")
		} else {
			fmt.Fprintf(os.Stderr, "ignoring experimental config. Use `--use-experimental-config` to include the experimental section in config\n")
			cfg.Experimental = nil
		}
	}

	return renderKubernetesObjects(cfgVersion, cfg)
}

func saveYamlToFiles(dir string, yaml []string) error {
	for i, mf := range yaml {
		objs, err := common.YamlToRuntimeObject([]string{mf})
		if err != nil {
			return err
		}
		obj := objs[0]
		fn := filepath.Join(dir, fmt.Sprintf("%03d_%s_%s.yaml", i, obj.Kind, obj.Metadata.Name))
		err = ioutil.WriteFile(fn, []byte(mf), 0644)
		if err != nil {
			return err
		}
	}
	return nil
}

func loadConfig(cfgFN string) (rawCfg interface{}, cfgVersion string, cfg *configv1.Config, err error) {
	var overrideConfig string
	// Update overrideConfig if cfgFN is not empty
	switch cfgFN {
	case "-":
		b, err := io.ReadAll(os.Stdin)
		if err != nil {
			return nil, "", nil, err
		}
		overrideConfig = string(b)
	case "":
		return nil, "", nil, fmt.Errorf("missing config file")
	default:
		cfgBytes, err := ioutil.ReadFile(cfgFN)
		if err != nil {
			panic(fmt.Sprintf("couldn't read file %s, %s", cfgFN, err))

		}
		overrideConfig = string(cfgBytes)
	}

	rawCfg, cfgVersion, err = config.Load(overrideConfig, rootOpts.StrictConfigParse)
	if err != nil {
		err = fmt.Errorf("error loading config: %w", err)
		return
	}
	if cfgVersion != config.CurrentVersion {
		err = fmt.Errorf("config version is mismatch: expected %s, got %s", config.CurrentVersion, cfgVersion)
		return
	}
	cfg = rawCfg.(*configv1.Config)

	return rawCfg, cfgVersion, cfg, err
}

func renderKubernetesObjects(cfgVersion string, cfg *configv1.Config) ([]string, error) {
	versionMF, err := getVersionManifest()
	if err != nil {
		return nil, err
	}

	if !renderOpts.ValidateConfigDisabled {
		apiVersion, err := config.LoadConfigVersion(cfgVersion)
		if err != nil {
			return nil, err
		}
		res, err := config.Validate(apiVersion, cfg)
		if err != nil {
			return nil, err
		}

		if !res.Valid {
			res.Marshal(os.Stderr)
			fmt.Fprintln(os.Stderr, "configuration is invalid")
			os.Exit(1)
		}

		// Warnings are printed to stderr
		for _, r := range res.Warnings {
			fmt.Fprintf(os.Stderr, "%s\n", r)
		}
	}

	ctx, err := common.NewRenderContext(*cfg, *versionMF, renderOpts.Namespace)
	if err != nil {
		return nil, err
	}

	var renderable common.RenderFunc
	var helmCharts common.HelmFunc
	switch cfg.Kind {
	case configv1.InstallationFull:
		renderable = components.FullObjects
		helmCharts = components.FullHelmDependencies
	case configv1.InstallationMeta:
		renderable = components.MetaObjects
		helmCharts = components.MetaHelmDependencies
	case configv1.InstallationIDE:
		renderable = components.IDEObjects
		helmCharts = components.IDEHelmDependencies
	case configv1.InstallationWebApp:
		renderable = components.WebAppObjects
		helmCharts = components.WebAppHelmDependencies
	case configv1.InstallationWorkspace:
		renderable = components.WorkspaceObjects
		helmCharts = components.WorkspaceHelmDependencies
	default:
		return nil, fmt.Errorf("unsupported installation kind: %s", cfg.Kind)
	}

	objs, err := common.CompositeRenderFunc(components.CommonObjects, renderable)(ctx)
	if err != nil {
		return nil, err
	}

	k8s := make([]string, 0)
	for _, o := range objs {
		fc, err := yaml.Marshal(o)
		if err != nil {
			return nil, err
		}

		k8s = append(k8s, fmt.Sprintf("---\n%s\n", string(fc)))
	}

	charts, err := common.CompositeHelmFunc(components.CommonHelmDependencies, helmCharts)(ctx)
	if err != nil {
		return nil, err
	}
	k8s = append(k8s, charts...)

	// convert everything to individual objects
	runtimeObjs, err := common.YamlToRuntimeObject(k8s)
	if err != nil {
		return nil, err
	}

	// generate a config map with every component installed
	runtimeObjsAndConfig, err := common.GenerateInstallationConfigMap(ctx, runtimeObjs)
	if err != nil {
		return nil, err
	}

	// sort the objects and return the plain YAML
	sortedObjs, err := common.DependencySortingRenderFunc(runtimeObjsAndConfig)
	if err != nil {
		return nil, err
	}

	postProcessed, err := postprocess.Run(sortedObjs)
	if err != nil {
		return nil, err
	}

	if err := ctx.WithExperimental(func(ucfg *experimental.Config) error {
		postProcessed, err = postprocess.Override(ucfg.Overrides, postProcessed)
		if err != nil {
			return err
		}
		return nil
	}); err != nil {
		return nil, err
	}

	// output the YAML to stdout
	output := make([]string, 0)
	for _, c := range postProcessed {
		output = append(output, fmt.Sprintf("---\n# %s/%s %s\n%s", c.TypeMeta.APIVersion, c.TypeMeta.Kind, c.Metadata.Name, c.Content))
	}

	return output, nil
}

func init() {
	rootCmd.AddCommand(renderCmd)

	dir, err := os.Getwd()
	if err != nil {
		log.WithError(err).Fatal("Failed to get working directory")
	}

	renderCmd.PersistentFlags().StringVarP(&renderOpts.ConfigFN, "config", "c", getEnvvar("GITPOD_INSTALLER_CONFIG", filepath.Join(dir, "gitpod.config.yaml")), "path to the config file, use - for stdin")
	renderCmd.PersistentFlags().StringVarP(&renderOpts.Namespace, "namespace", "n", getEnvvar("NAMESPACE", "default"), "namespace to deploy to")
	renderCmd.Flags().BoolVar(&renderOpts.ValidateConfigDisabled, "no-validation", false, "if set, the config will not be validated before running")
	renderCmd.Flags().BoolVar(&renderOpts.UseExperimentalConfig, "use-experimental-config", false, "enable the use of experimental config that is prone to be changed")
	renderCmd.Flags().StringVar(&renderOpts.FilesDir, "output-split-files", "", "path to output individual Kubernetes manifests to")
}