code

type Agent interface {
	// Name returns a stable identifier for this backend. For wingman
	// it's [BuiltinAgentName]; for ACP backends it's the [AgentDef.Name]
	// that constructed them.
	Name() string

	// Workspace returns the shared workspace the agent is rooted at.
	// Same instance regardless of which backend is active — its
	// Rewind / LSP / MCP subsystems are wingman-only side-effects but
	// the workspace itself (RootPath, Skills, MemoryPath) is shared.
	Workspace() *Workspace

	// Models reports the available model catalog and the currently
	// selected id. Cached read — no RPC. Empty list = the backend
	// doesn't expose a model selector.
	Models() (available []Model, current string)

	// SetModel switches the active model. Returns [errors.ErrUnsupported]
	// when the backend has no model selector.
	SetModel(ctx context.Context, id string) error

	// Effort reports the current effort id and the available values.
	// Empty options = effort selector not supported.
	Effort() (current string, options []string)

	SetEffort(ctx context.Context, value string) error

	// Modes reports the operating modes the backend exposes for the given
	// session and the currently active mode id. An empty list means the
	// backend has no mode selector (the UI hides the picker). Cached read —
	// no RPC.
	Modes(sessionID string) (available []Mode, current string)

	// SetMode switches the session's active operating mode. Returns
	// [errors.ErrUnsupported] when the backend has no mode selector, or an
	// error when modeID is not one of the advertised modes.
	SetMode(ctx context.Context, sessionID, modeID string) error

	// ListSessions returns the backend's saved session catalog scoped
	// to the workspace.
	ListSessions(ctx context.Context) ([]SessionInfo, error)

	// NewSession allocates a fresh session and returns its id. For
	// wingman this is a locally minted UUID; for ACP it's the id
	// returned by the ACP server's session/new.
	NewSession(ctx context.Context) (string, error)

	// LoadSession restores an existing session into memory so
	// [Messages] / [Usage] reflect its transcript and subsequent
	// [Send] calls continue it.
	LoadSession(ctx context.Context, id string) error

	// DeleteSession removes a session from the catalog. Returns
	// [errors.ErrUnsupported] when the backend can't delete (ACP).
	DeleteSession(ctx context.Context, id string) error

	// Messages returns the transcript for a session id. Returns nil
	// for sessions the backend hasn't loaded.
	Messages(sessionID string) []agent.Message

	Usage(sessionID string) agent.Usage

	// Send drives a turn. Returns nil when a turn is already running
	// for this session id. The iterator yields per-update chunks; the
	// implementation commits the assembled message(s) into the
	// session's transcript by end-of-turn.
	Send(ctx context.Context, sessionID string, input []agent.Content) iter.Seq2[agent.Message, error]

	// Cancel aborts an in-flight Send for the session id. No-op when
	// no turn is in flight or the id is unknown.
	Cancel(sessionID string)

	// Close releases all resources (subprocess, IO, file handles).
	// Idempotent.
	Close() error
}

type AgentDef struct {
	// Name is the user-facing label and the key used by [*Agent.SetAgent].
	Name string `json:"name"`

	// Command is the absolute path (or PATH-lookup name) of the ACP
	// server binary to spawn.
	Command string `json:"command"`

	// Args are extra arguments passed to the subprocess.
	Args []string `json:"args,omitempty"`

	// Env adds/overrides environment variables for the subprocess. The
	// parent process's environment is inherited.
	Env map[string]string `json:"env,omitempty"`
}

type Mode struct {
	ID          string
	Name        string
	Description string
}

type Model struct {
	ID   string
	Name string
}

type SessionInfo struct {
	ID        string
	Title     string
	UpdatedAt time.Time
}

type UI interface {
	Ask(ctx context.Context, message string) (string, error)
	Confirm(ctx context.Context, message string) (bool, error)
}

type Workspace struct {
	Root        *os.Root
	RootPath    string
	MemoryPath  string
	ScratchPath string

	Skills []skill.Skill

	MCP *mcp.Manager
	// LSP and Rewind are set by WarmUp; nil for unsupported workspaces.
	LSP    *lsp.Manager
	Rewind *rewind.Manager
	// contains filtered or unexported fields
}