package campaigns

import (
	"net/http"
	"sync"
	"time"

	"github.com/descrybe/descrybe-v2/apps/api/internal/aiprompts"
	"github.com/descrybe/descrybe-v2/apps/api/internal/aiprovider"
	"github.com/descrybe/descrybe-v2/apps/api/internal/billing"
	"github.com/descrybe/descrybe-v2/apps/api/internal/email"
	"github.com/descrybe/descrybe-v2/apps/api/internal/processing"
	"github.com/jackc/pgx/v5/pgxpool"
)

// Service is the email campaigns API surface (CRUD + generate + schedule/send).
// Tenant sending goes through email.Service (verified provider, rate limits, unsub).
type Service struct {
	Pool         *pgxpool.Pool
	Billing      *billing.Service
	Email        *email.Service
	Completer    processing.Completer
	AI           *aiprovider.Service
	Prompts      *aiprompts.Service
	WebOrigin    string
	PublicAPIURL string
	// TokenSigningSecret signs public brand-logo URLs for email embeds.
	TokenSigningSecret string
	HTTP               *http.Client

	genMu   sync.Mutex
	genHit  map[string][]time.Time
	sendMu  sync.Mutex
	sendHit map[string][]time.Time
}

func NewService(pool *pgxpool.Pool, billingSvc *billing.Service, emailSvc *email.Service) *Service {
	return &Service{
		Pool:    pool,
		Billing: billingSvc,
		Email:   emailSvc,
		HTTP:    &http.Client{Timeout: 30 * time.Second},
		genHit:  make(map[string][]time.Time),
		sendHit: make(map[string][]time.Time),
	}
}

const (
	generateRPM = 10
	sendRPM     = 20
)

func (s *Service) allowGenerate(companyID string) bool {
	return allowWindow(&s.genMu, s.genHit, companyID, generateRPM, time.Minute)
}

func (s *Service) allowSend(companyID string) bool {
	return allowWindow(&s.sendMu, s.sendHit, companyID, sendRPM, time.Minute)
}

func allowWindow(mu *sync.Mutex, hits map[string][]time.Time, key string, limit int, window time.Duration) bool {
	now := time.Now()
	cutoff := now.Add(-window)
	mu.Lock()
	defer mu.Unlock()
	ts := hits[key]
	kept := ts[:0]
	for _, t := range ts {
		if t.After(cutoff) {
			kept = append(kept, t)
		}
	}
	if len(kept) >= limit {
		hits[key] = kept
		return false
	}
	hits[key] = append(kept, now)
	return true
}