package cmd

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"time"

	"github.com/spf13/cobra"
	"github.com/warrenronsiek/ctask/internal/config"
	"github.com/warrenronsiek/ctask/internal/shell"
	"github.com/warrenronsiek/ctask/internal/workspace"
)

var resumeCmd = &cobra.Command{
	Use:          "resume <query>",
	Short:        "Reopen an existing workspace and launch the agent",
	Args:         cobra.ExactArgs(1),
	SilenceUsage: true,
	RunE:         runResume,
}

var (
	resumeContainer bool
	resumeShell     bool
	resumeAgent     string
	resumeForce     bool
	resumeDirect    bool
)

func init() {
	resumeCmd.Flags().BoolVar(&resumeContainer, "container", false, "Resume in container mode (deferred)")
	resumeCmd.Flags().BoolVar(&resumeShell, "shell", false, "Open shell instead of agent")
	resumeCmd.Flags().StringVarP(&resumeAgent, "agent", "a", "", "Override agent command")
	resumeCmd.Flags().BoolVar(&resumeForce, "force", false, "Skip active-session and stale-workspace warnings")
	resumeCmd.Flags().BoolVar(&resumeDirect, "direct", false, "Bypass persistent session mode for this command")
	resumeCmd.ValidArgsFunction = completeWorkspaces(completionActive)
	rootCmd.AddCommand(resumeCmd)
}

// errArchivedWorkspace is the sentinel doResume returns when the user
// asks to resume an archived workspace. doResume already prints the
// full [ctask] diagnostic + restore hint to stderr, so the cmd-layer
// wrapper flips SilenceErrors to suppress Cobra's redundant trailing
// "Error: workspace archived" line. All other errors (lookup failure,
// metadata write failure, etc.) flow through Cobra's default
// rendering unchanged.
var errArchivedWorkspace = errors.New("workspace archived")

func runResume(cmd *cobra.Command, args []string) error {
	err := doResume(args[0], resumeContainer, resumeShell, resumeForce, resumeAgent, resumeDirect)
	if errors.Is(err, errArchivedWorkspace) {
		cmd.SilenceErrors = true
	}
	return err
}

// doResume is the shared resume logic used by both `resume` and `last`.
// It preserves resume's existing archive-inclusive resolution and
// restore-hint behavior, then delegates to runWorkspaceEntry for the
// persistent-vs-direct decision and tmux dispatch.
func doResume(query string, container, useShell, force bool, agentOverride string, directFlag bool) error {
	if container {
		fmt.Println(shell.ContainerNotice())
		return nil
	}

	roots := config.SearchRoots()
	// resume resolves archived-inclusive so we can give a helpful hint when
	// the user resumes an archived workspace (v0.5.2 behavior — preserved).
	ws := resolveOne(roots, query, true)

	if ws.Meta.Status == "archived" {
		fmt.Fprint(os.Stderr, formatResumeRestoreHint(query))
		return errArchivedWorkspace
	}

	// updated_at bump (existing v0.4 behavior).
	now := time.Now().UTC().Truncate(time.Second)
	ws.Meta.UpdatedAt = now
	metaPath := filepath.Join(ws.Path, "task.yaml")
	if err := workspace.WriteMetaLocked(metaPath, ws.Meta); err != nil {
		return fmt.Errorf("updating metadata: %w", err)
	}

	resolved, err := resolveEntryAgent(ws.Meta.Agent, agentOverride)
	if err != nil {
		return err
	}

	return runWorkspaceEntry(WorkspaceEntryOptions{
		WsPath:        ws.Path,
		WsRoot:        ws.Root,
		WsMeta:        ws.Meta,
		ResolvedAgent: resolved,
		Shell:         useShell,
		Force:         force,
		Direct:        directFlag,
		CommandName:   "resume",
	})
}

// formatResumeRestoreHint builds the multi-line stderr block printed
// when `ctask resume <query>` resolves to an archived workspace.
// Extracted so the v0.5.4 invocation-name audit can verify the
// command-form line uses invocationName() without depending on the
// surrounding fmt.Fprintf machinery.
//
// The "[ctask]" diagnostic prefix is intentionally a literal product
// reference (spec §2: product-identity references stay literal). The
// `restore <query>` line is the command-form portion and uses
// invocationName().
func formatResumeRestoreHint(query string) string {
	return fmt.Sprintf(
		"[ctask] error: workspace %q is archived\n\nTo restore it:\n  %s restore %s\n",
		query, invocationName(), query)
}