package cli

import (
	"fmt"

	"github.com/spf13/cobra"
)

// newThreadsCmd turns conversation storage on for a project, or off.
//
// A command rather than a configuration key because it is a decision about
// data, not about deployment: someone has to choose to keep what a team types,
// and choosing it should look like an act rather than like a default nobody
// read.
//
// Until it is run for a project, llmgw stores no message content for that
// project — usage rows carry token counts and costs, never text — and that is
// how every project starts.
func newThreadsCmd(open opener) *cobra.Command {
	var (
		project string
		hours   int
		off     bool
	)

	cmd := &cobra.Command{
		Use:   "threads",
		Short: "Keep conversations for a project, so a thread can move between models",
		Long: "With this on, a client sends x-llmgw-thread and only its new turn, and\n" +
			"llmgw replays the conversation to whichever model serves — including a\n" +
			"different one from the one it started on.\n\n" +
			"Off for every project until this is run. llmgw otherwise stores no\n" +
			"message content anywhere, which is a much easier thing to have deployed\n" +
			"in front of a team, so turning it on is deliberate.\n\n" +
			"The retention is required rather than optional: a conversation store with\n" +
			"no expiry is a transcript of everything a team ever typed, kept forever\n" +
			"because nobody chose a number.",
		Args: cobra.NoArgs,
		RunE: func(cmd *cobra.Command, _ []string) error {
			if !off && hours <= 0 {
				return fmt.Errorf("--retain-hours is required: say how long conversations are kept, or pass --off")
			}
			s, err := open(cmd.Context())
			if err != nil {
				return err
			}
			defer s.Close()

			keep := hours
			if off {
				keep = 0
			}
			p, err := resolveProject(cmd.Context(), s, project)
			if err != nil {
				return err
			}
			project = p.Path
			if err := s.SetThreadRetention(cmd.Context(), p.ID, keep); err != nil {
				return err
			}
			if keep == 0 {
				fmt.Fprintf(cmd.OutOrStdout(),
					"%s keeps no conversations. Existing ones are removed at the next prune.\n", project)
				return nil
			}
			fmt.Fprintf(cmd.OutOrStdout(),
				"%s keeps conversations for %d hours, measured from the last turn.\n", project, keep)
			return nil
		},
	}
	cmd.Flags().StringVar(&project, "project", "", "project: id, path or unique name")
	cmd.Flags().IntVar(&hours, "retain-hours", 0, "how long a conversation is kept after its last turn")
	cmd.Flags().BoolVar(&off, "off", false, "stop keeping conversations for this project")
	return cmd
}