package ports

import (
	"context"
	"errors"
	"fmt"
)

// ConfigProvider returns dynamic auth/session configuration required by later
// service workflows.
type ConfigProvider interface {
	// LoadSessionLimit returns the current active-session-limit configuration.
	// A nil ActiveSessionLimit means that the limit is disabled.
	LoadSessionLimit(ctx context.Context) (SessionLimitConfig, error)
}

// SessionLimitConfig stores the active-session-limit configuration in a form
// that preserves “limit absent” as a first-class state.
type SessionLimitConfig struct {
	// ActiveSessionLimit stores the configured limit when one is present. Nil
	// means that no active-session limit is configured.
	ActiveSessionLimit *int
}

// Validate reports whether SessionLimitConfig contains a valid limit value
// when one is configured.
func (c SessionLimitConfig) Validate() error {
	if c.ActiveSessionLimit != nil && *c.ActiveSessionLimit <= 0 {
		return errors.New("session limit config active session limit must be positive when configured")
	}

	return nil
}

// String returns a debug-friendly representation of SessionLimitConfig.
func (c SessionLimitConfig) String() string {
	if c.ActiveSessionLimit == nil {
		return "session_limit=disabled"
	}

	return fmt.Sprintf("session_limit=%d", *c.ActiveSessionLimit)
}