package backthink

import (
	"fmt"

	"git.yeij.top/AskaEth/Cyrene_v2/internal/bus"
	"git.yeij.top/AskaEth/Cyrene_v2/internal/iot"
)

// Bus subjects the service subscribes to for event-triggered thinking. They are
// the contract defined by design/12 §1: an IoT state change, a reminder firing,
// or a generic system event.
const (
	// SubjectReminderTrigger is the bus subject on which reminders fire.
	SubjectReminderTrigger = "reminder.trigger"
	// SubjectSystemEvent is the bus subject for generic system events.
	SubjectSystemEvent = "system.event"
)

// SystemEvent is the optional typed payload a caller may publish to
// SubjectSystemEvent to convey a system notice. Import defaults to Normal. Under
// design/12 §6 策略一, a low-value system notice (a join/leave ping, generic
// platform noise) is downgraded to a registration-only record and does not wake a
// full thinking pass; only a high-importance (owner-relevant) system event thinks,
// so a busy public platform cannot trigger a flood of expensive reflections.
type SystemEvent struct {
	Summary string
	Import  Importance
}

// Trigger describes what woke a thinking pass: the source subsystem, a
// human-readable summary and the event's estimated importance.
type Trigger struct {
	Source  string
	Summary string
	Import  Importance
}

// heartbeatTrigger is the periodic, low-importance trigger. Low importance means
// the pass rarely interrupts the user, honouring "默认不发送 chat 类型消息".
func heartbeatTrigger() Trigger {
	return Trigger{Source: "heartbeat", Summary: "periodic autonomous reflection", Import: ImportanceLow}
}

// triggerForEvent maps a bus event to a Trigger. An IoT device change is treated
// as normal importance, a reminder firing as high importance, and a generic
// system event as normal importance.
func triggerForEvent(e bus.Event) Trigger {
	switch e.Subject {
	case iot.DeviceUpdateSubject:
		if d, ok := e.Payload.(iot.DeviceUpdate); ok {
			return Trigger{
				Source:  e.Subject,
				Summary: fmt.Sprintf("device %s (%s) %s", d.Device.ID, d.Device.Type, d.Action),
				Import:  ImportanceNormal,
			}
		}
		return Trigger{Source: e.Subject, Summary: e.Subject, Import: ImportanceNormal}
	case SubjectReminderTrigger:
		return Trigger{Source: e.Subject, Summary: e.Subject, Import: ImportanceHigh}
	case SubjectSystemEvent:
		tr := Trigger{Source: e.Subject, Summary: e.Subject, Import: ImportanceNormal}
		if sy, ok := e.Payload.(SystemEvent); ok {
			if sy.Summary != "" {
				tr.Summary = sy.Summary
			}
			tr.Import = sy.Import
		}
		return tr
	default:
		return Trigger{Source: e.Subject, Summary: e.Subject, Import: ImportanceNormal}
	}
}