// Package identity is executus's caller-identity seam.
//
// A CallerID is an opaque string the host assigns (a Discord snowflake, an OAuth
// subject, a CI principal). Two optional capabilities hang off it: AdminPolicy
// gates authoring-class actions, and MemberResolver supplies per-caller
// enrichment (timezone, display name) for tools that want it. Both are nil-safe
// so a host that has no notion of "members" or "admins" wires nothing — the
// defaults treat everyone as a non-admin unknown.
package identity

import "context"

// Member is optional per-caller enrichment. Attrs carries host-specific extras
// (a seerr user id, a persona blurb) without widening this struct per host.
type Member struct {
	ID          string
	DisplayName string
	Timezone    string
	Attrs       map[string]string
}

// AdminPolicy decides whether a caller may perform authoring-class actions
// (saving a shared skill, registering an agent). Default: NonAdmin.
type AdminPolicy interface {
	IsAdmin(ctx context.Context, callerID string) bool
}

// NonAdmin is the default policy: nobody is an admin. A single-principal host
// (a CI job) typically overrides with a constant-true policy for its principal.
type NonAdmin struct{}

func (NonAdmin) IsAdmin(context.Context, string) bool { return false }

// MemberResolver supplies optional enrichment for a CallerID. ok=false means the
// member is unknown (the harness then proceeds without enrichment).
type MemberResolver interface {
	Resolve(ctx context.Context, callerID string) (Member, bool)
}

// IsAdmin is the nil-safe accessor: a nil AdminPolicy denies.
func IsAdmin(p AdminPolicy, ctx context.Context, callerID string) bool {
	if p == nil {
		return false
	}
	return p.IsAdmin(ctx, callerID)
}

// Resolve is the nil-safe accessor: a nil resolver returns an unknown member.
func Resolve(r MemberResolver, ctx context.Context, callerID string) (Member, bool) {
	if r == nil {
		return Member{}, false
	}
	return r.Resolve(ctx, callerID)
}