package usecase

import (
	"context"
	"fmt"
	"strings"

	"apps/backend/internal/module/radar/domain"
)

// HealthGate checks AccountHealth before auto-send (outbox path).
// Level: ok | warn | throttle. Throttle must block automatic send.
type HealthGate interface {
	// WorstLevel returns the worst health level among usable accounts for owner.
	WorstLevel(ctx context.Context, ownerUID int64) (level string, advice string, err error)
}

// MarkReplyUsed records that a draft was sent or copied (T550).
// channel: outbox | manual_copy
// - dm variants: only manual_copy
// - outbox: rejects when health=throttle; warn still allowed (caller may surface advice)
func (s *Service) MarkReplyUsed(ctx context.Context, ownerUID int64, opportunityID, replyID, channel string) (*domain.ReplyVariant, string, error) {
	channel = strings.TrimSpace(channel)
	if channel != domain.SentOutbox && channel != domain.SentManualCopy {
		return nil, "", fmt.Errorf("%w: channel must be outbox or manual_copy", domain.ErrValidation)
	}
	o, err := s.GetOpportunity(ctx, ownerUID, opportunityID)
	if err != nil {
		return nil, "", err
	}
	_ = o
	r, err := s.Repo.GetReply(ctx, replyID)
	if err != nil {
		return nil, "", err
	}
	if r.OwnerUID != ownerUID || r.OpportunityID != opportunityID {
		return nil, "", domain.ErrForbidden
	}
	if r.Variant == domain.ReplyDM && channel == domain.SentOutbox {
		return nil, "", fmt.Errorf("%w: dm reply cannot auto-send; use manual_copy", domain.ErrValidation)
	}

	var healthAdvice string
	if channel == domain.SentOutbox {
		if s.Health == nil {
			// No gate wired: still allow mark-used so offline demos work; production wires Health.
		} else {
			level, advice, herr := s.Health.WorstLevel(ctx, ownerUID)
			if herr != nil {
				return nil, "", herr
			}
			if level == "throttle" {
				return nil, advice, fmt.Errorf("%w: account health throttle blocks auto-send; copy and send manually", domain.ErrValidation)
			}
			if level == "warn" {
				healthAdvice = advice
				if healthAdvice == "" {
					healthAdvice = "帳號健康度偏黃，建議放慢自動送出。"
				}
			}
		}
	}

	r.UsedAt = domain.NowNano()
	r.SentChannel = channel
	if err := s.Repo.SaveReply(ctx, r); err != nil {
		return nil, "", err
	}
	return r, healthAdvice, nil
}