package cmd

import (
	"fmt"

	"github.com/jensbecker/homelab/knecht/portainer"
	"github.com/jensbecker/homelab/knecht/stack"
	"github.com/jensbecker/homelab/knecht/tui"
	"github.com/spf13/cobra"
)

var pruneEnvFlag bool

var updateCmd = &cobra.Command{
	Use:   "update <stack>",
	Short: "Update an existing stack, preserving env vars",
	Args:  cobra.ExactArgs(1),
	RunE: func(cmd *cobra.Command, args []string) error {
		_, client, svcPath, err := setup()
		if err != nil {
			return err
		}

		name := args[0]
		local, err := stack.Get(svcPath, name)
		if err != nil {
			return err
		}

		remote, err := client.GetStackByName(name)
		if err != nil {
			return err
		}
		if remote == nil {
			return fmt.Errorf("stack %q not found — use `knecht deploy %s` to create it", name, name)
		}

		compose, err := local.ReadCompose()
		if err != nil {
			return err
		}

		exampleKeys, err := local.EnvExampleKeys()
		if err != nil {
			return err
		}

		env, err := mergeEnvVars(name, remote.Env, exampleKeys, pruneEnvFlag)
		if err != nil {
			return err
		}
		if env == nil {
			fmt.Println("Cancelled.")
			return nil
		}

		s, err := client.UpdateStack(remote.ID, compose, env)
		if err != nil {
			return err
		}
		fmt.Printf("Updated stack %q (id %d)\n", s.Name, s.ID)
		return nil
	},
}

// mergeEnvVars preserves existing Portainer env vars and prompts via TUI for
// any keys present in .env.example but missing from Portainer.
// Returns nil if the user cancelled the form.
func mergeEnvVars(stackName string, existing []portainer.EnvVar, exampleKeys []string, prune bool) ([]portainer.EnvVar, error) {
	envMap := make(map[string]string, len(existing))
	for _, e := range existing {
		envMap[e.Name] = e.Value
	}

	// Remove keys not in .env.example when pruning
	if prune && exampleKeys != nil {
		allowed := make(map[string]bool, len(exampleKeys))
		for _, k := range exampleKeys {
			allowed[k] = true
		}
		for k := range envMap {
			if !allowed[k] {
				fmt.Printf("Removing unknown env var %q\n", k)
				delete(envMap, k)
			}
		}
	}

	var missing []string
	for _, key := range exampleKeys {
		if _, ok := envMap[key]; !ok {
			missing = append(missing, key)
		}
	}

	if len(missing) > 0 {
		values, err := tui.PromptMissingEnv(stackName, missing)
		if err != nil {
			return nil, err
		}
		if values == nil {
			return nil, nil // cancelled
		}
		for k, v := range values {
			envMap[k] = v
		}
	}

	result := make([]portainer.EnvVar, 0, len(envMap))
	for k, v := range envMap {
		result = append(result, portainer.EnvVar{Name: k, Value: v})
	}
	return result, nil
}

func init() {
	updateCmd.Flags().BoolVar(&pruneEnvFlag, "prune-env", false, "remove env vars not defined in .env.example")
	rootCmd.AddCommand(updateCmd)
}