package sessioncmd

import (
	"context"
	"fmt"

	"github.com/spf13/cobra"

	"github.com/Tencent/WeKnora/cli/internal/agent"
	"github.com/Tencent/WeKnora/cli/internal/cmdutil"
	"github.com/Tencent/WeKnora/cli/internal/format"
	"github.com/Tencent/WeKnora/cli/internal/iostreams"
	"github.com/Tencent/WeKnora/cli/internal/prompt"
)

type DeleteOptions struct {
	Yes     bool // sourced from the global -y/--yes persistent flag
	JSONOut bool
	DryRun  bool
}

// DeleteService is the narrow SDK surface this command depends on.
type DeleteService interface {
	DeleteSession(ctx context.Context, id string) error
}

// deleteResult is the typed payload emitted under data on success.
type deleteResult struct {
	ID      string `json:"id"`
	Deleted bool   `json:"deleted"`
}

// NewCmdDelete builds `weknora session delete`. Destructive write gated
// by -y/--yes (exit-10 protocol in scripted / --json invocations).
func NewCmdDelete(f *cmdutil.Factory) *cobra.Command {
	opts := &DeleteOptions{}
	cmd := &cobra.Command{
		Use:   "delete <id>",
		Short: "Delete a chat session",
		Long: `Permanently delete a chat session and its messages.

Prompts for confirmation by default when stdout is a TTY and --json is not set.
Pass -y/--yes (global flag) to skip the prompt (required in agent / CI / piped contexts).

AI agents: This is a high-risk write. Without -y/--yes the CLI exits 10 and
returns an envelope describing the missing confirmation. NEVER auto-pass -y
without the user's explicit go-ahead.`,
		Example: `  weknora session delete s_abc          # interactive confirm
  weknora session delete s_abc -y       # no prompt
  weknora session delete s_abc -y --json`,
		Args: cobra.ExactArgs(1),
		RunE: func(c *cobra.Command, args []string) error {
			opts.Yes, _ = c.Flags().GetBool("yes")
			opts.DryRun = cmdutil.IsDryRun(c)
			if opts.DryRun {
				return runDelete(c.Context(), opts, nil, f.Prompter(), args[0])
			}
			cli, err := f.Client()
			if err != nil {
				return err
			}
			return runDelete(c.Context(), opts, cli, f.Prompter(), args[0])
		},
	}
	cmd.Flags().BoolVar(&opts.JSONOut, "json", false, "Output JSON envelope")
	agent.SetAgentHelp(cmd, "Destructively deletes a chat session by id. ALWAYS pass -y/--yes in agent mode (no TTY ⇒ confirm prompt fails). Returns data: {id, deleted:true}.")
	return cmd
}

func runDelete(ctx context.Context, opts *DeleteOptions, svc DeleteService, p prompt.Prompter, id string) error {
	risk := &format.Risk{Level: format.RiskHighRiskWrite, Action: fmt.Sprintf("delete session %s", id)}

	if opts.DryRun {
		return cmdutil.EmitDryRun(opts.JSONOut,
			deleteResult{ID: id, Deleted: false}, nil, risk)
	}

	if err := cmdutil.ConfirmDestructive(p, opts.Yes, opts.JSONOut, "session", id); err != nil {
		return err
	}

	if err := svc.DeleteSession(ctx, id); err != nil {
		return cmdutil.WrapHTTP(err, "delete session %s", id)
	}

	if opts.JSONOut {
		return format.WriteEnvelope(iostreams.IO.Out, format.SuccessWithRisk(
			deleteResult{ID: id, Deleted: true}, nil, risk,
		))
	}
	fmt.Fprintf(iostreams.IO.Out, "✓ Deleted session %s\n", id)
	return nil
}