package template

import (
	_ "embed"
	"encoding/json"
	"fmt"
	"os"

	"github.com/stackitcloud/stackit-cli/internal/pkg/types"

	"github.com/goccy/go-yaml"
	"github.com/spf13/cobra"
	"github.com/stackitcloud/stackit-cli/internal/pkg/args"
	"github.com/stackitcloud/stackit-cli/internal/pkg/errors"
	"github.com/stackitcloud/stackit-cli/internal/pkg/examples"
	"github.com/stackitcloud/stackit-cli/internal/pkg/flags"
	"github.com/stackitcloud/stackit-cli/internal/pkg/globalflags"
	"github.com/stackitcloud/stackit-cli/internal/pkg/print"
	"github.com/stackitcloud/stackit-cli/internal/pkg/utils"
	"github.com/stackitcloud/stackit-sdk-go/services/alb"
)

const (
	formatFlag = "format"
	typeFlag   = "type"
)

type inputModel struct {
	*globalflags.GlobalFlagModel
	Format *string
	Type   *string
}

var (
	//go:embed template-alb.yaml
	templateAlb string
	//go:embed template-pool.yaml
	templatePool string
)

func NewCmd(params *types.CmdParams) *cobra.Command {
	cmd := &cobra.Command{
		Use:   "template",
		Short: "creates configuration templates to use for resource creation",
		Long:  "creates a json or yaml template file for creating/updating an application loadbalancer or target pool.",
		Args:  args.NoArgs,
		Example: examples.Build(
			examples.NewExample(
				`Create a yaml template`,
				`$ stackit beta alb template --format=yaml --type alb`,
			),
			examples.NewExample(
				`Create a json template`,
				`$ stackit beta alb template --format=json --type pool`,
			),
		),
		RunE: func(cmd *cobra.Command, args []string) error {
			model, err := parseInput(params.Printer, cmd, args)
			if err != nil {
				return err
			}

			var (
				template string
				target   any
			)
			if model.Type != nil && *model.Type == "pool" {
				template = templatePool
				target = alb.CreateLoadBalancerPayload{}
			} else if model.Type == nil || *model.Type == "alb" {
				template = templateAlb
				target = alb.UpdateTargetPoolPayload{}
			} else {
				return fmt.Errorf("invalid type %q", utils.PtrString(model.Type))
			}

			if model.Format == nil || *model.Format == "yaml" {
				params.Printer.Outputln(template)
			} else if *model.Format == "json" {
				if err := yaml.Unmarshal([]byte(template), &target); err != nil {
					return fmt.Errorf("cannot unmarshal template: %w", err)
				}
				encoder := json.NewEncoder(os.Stdout)
				if err := encoder.Encode(target); err != nil {
					return fmt.Errorf("cannot marshal template to yaml: %w", err)
				}
			} else {
				return fmt.Errorf("invalid format %q defined. Must be 'json' or 'yaml'", *model.Format)
			}

			return nil
		},
	}

	configureFlags(cmd)
	return cmd
}

func configureFlags(cmd *cobra.Command) {
	cmd.Flags().VarP(flags.EnumFlag(true, "json", "json", "yaml"), formatFlag, "f", "Defines the output format ('yaml' or 'json'), default is 'json'")
	cmd.Flags().VarP(flags.EnumFlag(true, "alb", "alb", "pool"), typeFlag, "t", "Defines the output type ('alb' or 'pool'), default is 'alb'")
}

func parseInput(p *print.Printer, cmd *cobra.Command, _ []string) (*inputModel, error) {
	globalFlags := globalflags.Parse(p, cmd)
	if globalFlags.ProjectId == "" {
		return nil, &errors.ProjectIdError{}
	}

	model := inputModel{
		GlobalFlagModel: globalFlags,
		Format:          flags.FlagToStringPointer(p, cmd, formatFlag),
		Type:            flags.FlagToStringPointer(p, cmd, typeFlag),
	}

	p.DebugInputModel(model)
	return &model, nil
}
