package repository

import (
	"baron-sso-backend/internal/domain"
	"context"
	"strings"

	"gorm.io/gorm"
	"gorm.io/gorm/clause"
)

type UserRepository interface {
	Create(ctx context.Context, user *domain.User) error
	Update(ctx context.Context, user *domain.User) error
	FindByEmail(ctx context.Context, email string) (*domain.User, error)
	FindByID(ctx context.Context, id string) (*domain.User, error)
	FindByIDs(ctx context.Context, ids []string) ([]domain.User, error)
	ListByTenant(ctx context.Context, tenantID string) ([]domain.User, error)
	List(ctx context.Context, offset, limit int, search string, companyCode string) ([]domain.User, int64, error)
	CountByTenant(ctx context.Context, tenantID string) (int64, error)
	CountByTenantIDs(ctx context.Context, tenantIDs []string) (map[string]int64, error)
	CountByCompanyCodes(ctx context.Context, codes []string) (map[string]int64, error)
	Delete(ctx context.Context, id string) error
}

type userRepository struct {
	db *gorm.DB
}

func NewUserRepository(db *gorm.DB) UserRepository {
	return &userRepository{db: db}
}

func (r *userRepository) Create(ctx context.Context, user *domain.User) error {
	return r.db.WithContext(ctx).Create(user).Error
}

func (r *userRepository) Update(ctx context.Context, user *domain.User) error {
	// Use Upsert logic: if email exists, update all fields
	return r.db.WithContext(ctx).Clauses(clause.OnConflict{
		Columns:   []clause.Column{{Name: "email"}},
		UpdateAll: true,
	}).Save(user).Error
}

func (r *userRepository) FindByEmail(ctx context.Context, email string) (*domain.User, error) {
	var user domain.User
	if err := r.db.WithContext(ctx).Preload("Tenant").Where("email = ?", email).First(&user).Error; err != nil {
		return nil, err
	}
	return &user, nil
}

func (r *userRepository) FindByID(ctx context.Context, id string) (*domain.User, error) {
	var user domain.User
	if err := r.db.WithContext(ctx).Preload("Tenant").Where("id = ?", id).First(&user).Error; err != nil {
		return nil, err
	}
	return &user, nil
}

func (r *userRepository) FindByIDs(ctx context.Context, ids []string) ([]domain.User, error) {
	var users []domain.User
	if len(ids) == 0 {
		return users, nil
	}
	if err := r.db.WithContext(ctx).Where("id IN ?", ids).Find(&users).Error; err != nil {
		return nil, err
	}
	return users, nil
}

func (r *userRepository) ListByTenant(ctx context.Context, tenantID string) ([]domain.User, error) {
	var users []domain.User
	if err := r.db.WithContext(ctx).Where("tenant_id = ?", tenantID).Find(&users).Error; err != nil {
		return nil, err
	}
	return users, nil
}

func (r *userRepository) CountByTenant(ctx context.Context, tenantID string) (int64, error) {
	var count int64
	err := r.db.WithContext(ctx).Model(&domain.User{}).Where("tenant_id = ?", tenantID).Count(&count).Error
	return count, err
}

func (r *userRepository) CountByTenantIDs(ctx context.Context, tenantIDs []string) (map[string]int64, error) {
	type result struct {
		TenantID *string
		Count    int64
	}
	var results []result
	counts := make(map[string]int64)

	if len(tenantIDs) == 0 {
		return counts, nil
	}

	if err := r.db.WithContext(ctx).Model(&domain.User{}).
		Select("tenant_id, count(*) as count").
		Where("tenant_id IN ?", tenantIDs).
		Group("tenant_id").
		Find(&results).Error; err != nil {
		return nil, err
	}

	for _, res := range results {
		if res.TenantID != nil && *res.TenantID != "" {
			counts[*res.TenantID] = res.Count
		}
	}
	// Ensure all requested tenant IDs are in the map, even if count is 0
	for _, id := range tenantIDs {
		if _, ok := counts[id]; !ok {
			counts[id] = 0
		}
	}
	return counts, nil
}

func (r *userRepository) CountByCompanyCodes(ctx context.Context, codes []string) (map[string]int64, error) {
	if len(codes) == 0 {
		return make(map[string]int64), nil
	}

	type result struct {
		CompanyCode string
		Count       int64
	}
	var results []result

	// Search by company_code directly. Normalize inputs using LOWER for robust matching.
	err := r.db.WithContext(ctx).Model(&domain.User{}).
		Select("LOWER(company_code) as company_code, count(*) as count").
		Where("LOWER(company_code) IN ?", lowerStrings(codes)).
		Group("LOWER(company_code)").
		Scan(&results).Error
	if err != nil {
		return nil, err
	}

	counts := make(map[string]int64)
	for _, res := range results {
		counts[res.CompanyCode] = res.Count
	}

	// Ensure all requested codes are present in results (even if count is 0)
	for _, code := range codes {
		lower := strings.ToLower(strings.TrimSpace(code))
		if _, ok := counts[lower]; !ok {
			counts[lower] = 0
		}
	}

	return counts, nil
}

func lowerStrings(arr []string) []string {
	res := make([]string, len(arr))
	for i, s := range arr {
		res[i] = strings.ToLower(strings.TrimSpace(s))
	}
	return res
}

func (r *userRepository) List(ctx context.Context, offset, limit int, search string, companyCode string) ([]domain.User, int64, error) {
	var users []domain.User
	var total int64
	db := r.db.WithContext(ctx).Model(&domain.User{})

	if companyCode != "" {
		db = db.Where("company_code = ?", companyCode)
	}

	if search != "" {
		searchTerm := "%" + search + "%"
		// Search in basic fields and metadata (PostgreSQL JSONB)
		db = db.Where("(email LIKE ? OR name LIKE ? OR company_code LIKE ? OR metadata::text LIKE ?)",
			searchTerm, searchTerm, searchTerm, searchTerm)
	}

	if err := db.Count(&total).Error; err != nil {
		return nil, 0, err
	}

	if err := db.Offset(offset).Limit(limit).Find(&users).Error; err != nil {
		return nil, 0, err
	}

	return users, total, nil
}

func (r *userRepository) Delete(ctx context.Context, id string) error {
	return r.db.WithContext(ctx).Delete(&domain.User{}, "id = ?", id).Error
}