package service

import (
	"dal-license-server/internal/model"
	"dal-license-server/internal/repository"
	"database/sql"
	"encoding/json"
	"fmt"
	"time"
)

type LicenseService struct {
	repo    *repository.LicenseRepo
	audit   *repository.AuditRepo
}

func NewLicenseService(repo *repository.LicenseRepo, audit *repository.AuditRepo) *LicenseService {
	return &LicenseService{repo: repo, audit: audit}
}

func (s *LicenseService) Create(req *model.CreateLicenseRequest, ip string) (*model.License, error) {
	product, err := s.repo.GetProductByID(req.ProductID)
	if err != nil {
		return nil, fmt.Errorf("product not found: %w", err)
	}

	key, err := GenerateKey(product.KeyPrefix)
	if err != nil {
		return nil, fmt.Errorf("generate key: %w", err)
	}

	limits := req.Limits
	if len(limits) == 0 || string(limits) == "" || string(limits) == "null" {
		limits = product.DefaultLimits
	}
	features := req.Features
	if len(features) == 0 || string(features) == "" || string(features) == "null" {
		features = product.AvailableFeatures
	}
	graceDays := req.GraceDays
	if graceDays == 0 {
		graceDays = 30
	}

	l := &model.License{
		ProductID:     req.ProductID,
		LicenseKey:    key,
		LicenseType:   req.LicenseType,
		CustomerName:  req.CustomerName,
		CustomerPIB:   req.CustomerPIB,
		CustomerEmail: req.CustomerEmail,
		Limits:        limits,
		Features:      features,
		GraceDays:     graceDays,
		Notes:         req.Notes,
	}

	// Set expiry
	switch req.LicenseType {
	case "TRIAL":
		exp := time.Now().AddDate(0, 0, 30)
		l.ExpiresAt = sql.NullTime{Time: exp, Valid: true}
	case "MONTHLY":
		exp := time.Now().AddDate(0, 1, 0)
		l.ExpiresAt = sql.NullTime{Time: exp, Valid: true}
	case "ANNUAL":
		exp := time.Now().AddDate(1, 0, 0)
		l.ExpiresAt = sql.NullTime{Time: exp, Valid: true}
	case "PERPETUAL":
		l.ExpiresAt = sql.NullTime{Valid: false}
	}

	id, err := s.repo.Create(l)
	if err != nil {
		return nil, err
	}

	s.audit.Log(&id, "CREATE", ip, map[string]interface{}{
		"product": product.Code,
		"type":    req.LicenseType,
		"customer": req.CustomerName,
	})

	return s.repo.GetByID(id)
}

func (s *LicenseService) GetByID(id int64) (*model.License, error) {
	return s.repo.GetByID(id)
}

func (s *LicenseService) GetByKey(key string) (*model.License, error) {
	return s.repo.GetByKey(key)
}

func (s *LicenseService) List(productCode, status, search string) ([]model.LicenseWithActivation, error) {
	return s.repo.List(productCode, status, search)
}

func (s *LicenseService) Update(id int64, req *model.UpdateLicenseRequest, ip string) error {
	l, err := s.repo.GetByID(id)
	if err != nil {
		return err
	}

	l.CustomerName = req.CustomerName
	l.CustomerPIB = req.CustomerPIB
	l.CustomerEmail = req.CustomerEmail
	l.Notes = req.Notes
	if len(req.Limits) > 0 {
		l.Limits = req.Limits
	}
	if len(req.Features) > 0 {
		l.Features = req.Features
	}
	if req.GraceDays > 0 {
		l.GraceDays = req.GraceDays
	}
	if req.ExpiresAt != "" {
		t, err := time.Parse("2006-01-02", req.ExpiresAt)
		if err == nil {
			l.ExpiresAt = sql.NullTime{Time: t, Valid: true}
		}
	}

	s.audit.Log(&id, "UPDATE", ip, map[string]interface{}{"customer": req.CustomerName})
	return s.repo.Update(l)
}

func (s *LicenseService) Revoke(id int64, reason, ip string) error {
	s.audit.Log(&id, "REVOKE", ip, map[string]interface{}{"reason": reason})
	return s.repo.Revoke(id, reason)
}

func (s *LicenseService) GetProducts() ([]model.Product, error) {
	return s.repo.GetProducts()
}

func (s *LicenseService) GetStats() (*model.StatsResponse, error) {
	stats := &model.StatsResponse{}
	byProduct, err := s.repo.CountByProduct()
	if err != nil {
		return nil, err
	}
	stats.ByProduct = byProduct

	for _, p := range byProduct {
		stats.TotalLicenses += p.Total
		stats.ActiveLicenses += p.Active
		stats.ExpiredLicenses += p.Expired
		stats.RevokedLicenses += p.Trial // count trials separately
		stats.ActiveActivations += p.ActiveActivations
	}

	// Fix: count revoked properly
	var revoked int
	for _, p := range byProduct {
		_ = p // need a separate query for revoked
	}
	_ = revoked

	licenses, _ := s.repo.List("", "revoked", "")
	stats.RevokedLicenses = len(licenses)

	return stats, nil
}

func (s *LicenseService) ExpiringIn(days int) ([]model.License, error) {
	return s.repo.ExpiringIn(days)
}

func (s *LicenseService) BuildLicenseData(l *model.License, fingerprint string) ([]byte, error) {
	expiresAt := ""
	if l.ExpiresAt.Valid {
		expiresAt = l.ExpiresAt.Time.Format(time.RFC3339)
	}

	ld := model.LicenseData{
		LicenseKey:         l.LicenseKey,
		Product:            l.ProductCode,
		LicenseType:        l.LicenseType,
		IssuedAt:           l.IssuedAt.Format(time.RFC3339),
		ExpiresAt:          expiresAt,
		ActivatedAt:        time.Now().Format(time.RFC3339),
		MachineFingerprint: fingerprint,
		GraceDays:          l.GraceDays,
		Limits:             l.Limits,
		Features:           l.Features,
		Customer: model.CustomerData{
			Name:  l.CustomerName,
			Email: l.CustomerEmail,
		},
	}

	return json.Marshal(ld)
}