package repository

import (
	"fmt"
	"strings"
	"time"

	"git.mchus.pro/mchus/quoteforge/internal/models"
	"gorm.io/gorm"
)

type PricelistRepository struct {
	db *gorm.DB
}

func NewPricelistRepository(db *gorm.DB) *PricelistRepository {
	return &PricelistRepository{db: db}
}

// List returns pricelists with pagination
func (r *PricelistRepository) List(offset, limit int) ([]models.PricelistSummary, int64, error) {
	var total int64
	if err := r.db.Model(&models.Pricelist{}).Count(&total).Error; err != nil {
		return nil, 0, fmt.Errorf("counting pricelists: %w", err)
	}

	var pricelists []models.Pricelist
	if err := r.db.Order("created_at DESC").Offset(offset).Limit(limit).Find(&pricelists).Error; err != nil {
		return nil, 0, fmt.Errorf("listing pricelists: %w", err)
	}

	// Get item counts for each pricelist
	summaries := make([]models.PricelistSummary, len(pricelists))
	for i, pl := range pricelists {
		var itemCount int64
		r.db.Model(&models.PricelistItem{}).Where("pricelist_id = ?", pl.ID).Count(&itemCount)

		summaries[i] = models.PricelistSummary{
			ID:           pl.ID,
			Version:      pl.Version,
			Notification: pl.Notification,
			CreatedAt:    pl.CreatedAt,
			CreatedBy:    pl.CreatedBy,
			IsActive:     pl.IsActive,
			UsageCount:   pl.UsageCount,
			ExpiresAt:    pl.ExpiresAt,
			ItemCount:    itemCount,
		}
	}

	return summaries, total, nil
}

// GetByID returns a pricelist by ID
func (r *PricelistRepository) GetByID(id uint) (*models.Pricelist, error) {
	var pricelist models.Pricelist
	if err := r.db.First(&pricelist, id).Error; err != nil {
		return nil, fmt.Errorf("getting pricelist: %w", err)
	}

	// Get item count
	var itemCount int64
	r.db.Model(&models.PricelistItem{}).Where("pricelist_id = ?", id).Count(&itemCount)
	pricelist.ItemCount = int(itemCount)

	return &pricelist, nil
}

// GetByVersion returns a pricelist by version string
func (r *PricelistRepository) GetByVersion(version string) (*models.Pricelist, error) {
	var pricelist models.Pricelist
	if err := r.db.Where("version = ?", version).First(&pricelist).Error; err != nil {
		return nil, fmt.Errorf("getting pricelist by version: %w", err)
	}
	return &pricelist, nil
}

// GetLatestActive returns the most recent active pricelist
func (r *PricelistRepository) GetLatestActive() (*models.Pricelist, error) {
	var pricelist models.Pricelist
	if err := r.db.Where("is_active = ?", true).Order("created_at DESC").First(&pricelist).Error; err != nil {
		return nil, fmt.Errorf("getting latest pricelist: %w", err)
	}
	return &pricelist, nil
}

// Create creates a new pricelist
func (r *PricelistRepository) Create(pricelist *models.Pricelist) error {
	if err := r.db.Create(pricelist).Error; err != nil {
		return fmt.Errorf("creating pricelist: %w", err)
	}
	return nil
}

// Update updates a pricelist
func (r *PricelistRepository) Update(pricelist *models.Pricelist) error {
	if err := r.db.Save(pricelist).Error; err != nil {
		return fmt.Errorf("updating pricelist: %w", err)
	}
	return nil
}

// Delete deletes a pricelist if usage_count is 0
func (r *PricelistRepository) Delete(id uint) error {
	pricelist, err := r.GetByID(id)
	if err != nil {
		return err
	}

	if pricelist.UsageCount > 0 {
		return fmt.Errorf("cannot delete pricelist with usage_count > 0 (current: %d)", pricelist.UsageCount)
	}

	// Delete items first
	if err := r.db.Where("pricelist_id = ?", id).Delete(&models.PricelistItem{}).Error; err != nil {
		return fmt.Errorf("deleting pricelist items: %w", err)
	}

	// Delete pricelist
	if err := r.db.Delete(&models.Pricelist{}, id).Error; err != nil {
		return fmt.Errorf("deleting pricelist: %w", err)
	}

	return nil
}

// CreateItems batch inserts pricelist items
func (r *PricelistRepository) CreateItems(items []models.PricelistItem) error {
	if len(items) == 0 {
		return nil
	}

	// Use batch insert for better performance
	batchSize := 500
	for i := 0; i < len(items); i += batchSize {
		end := i + batchSize
		if end > len(items) {
			end = len(items)
		}
		if err := r.db.CreateInBatches(items[i:end], batchSize).Error; err != nil {
			return fmt.Errorf("batch inserting pricelist items: %w", err)
		}
	}
	return nil
}

// GetItems returns pricelist items with pagination
func (r *PricelistRepository) GetItems(pricelistID uint, offset, limit int, search string) ([]models.PricelistItem, int64, error) {
	var total int64
	query := r.db.Model(&models.PricelistItem{}).Where("pricelist_id = ?", pricelistID)

	if search != "" {
		query = query.Where("lot_name LIKE ?", "%"+search+"%")
	}

	if err := query.Count(&total).Error; err != nil {
		return nil, 0, fmt.Errorf("counting pricelist items: %w", err)
	}

	var items []models.PricelistItem
	if err := query.Order("lot_name").Offset(offset).Limit(limit).Find(&items).Error; err != nil {
		return nil, 0, fmt.Errorf("listing pricelist items: %w", err)
	}

	// Enrich with lot descriptions
	for i := range items {
		var lot models.Lot
		if err := r.db.Where("lot_name = ?", items[i].LotName).First(&lot).Error; err == nil {
			items[i].LotDescription = lot.LotDescription
		}
		// Parse category from lot_name (e.g., "CPU_AMD_9654" -> "CPU")
		parts := strings.SplitN(items[i].LotName, "_", 2)
		if len(parts) >= 1 {
			items[i].Category = parts[0]
		}
	}

	return items, total, nil
}

// GenerateVersion generates a new version string in format YYYY-MM-DD-NNN
func (r *PricelistRepository) GenerateVersion() (string, error) {
	today := time.Now().Format("2006-01-02")

	var count int64
	if err := r.db.Model(&models.Pricelist{}).
		Where("version LIKE ?", today+"%").
		Count(&count).Error; err != nil {
		return "", fmt.Errorf("counting today's pricelists: %w", err)
	}

	return fmt.Sprintf("%s-%03d", today, count+1), nil
}

// CanWrite checks if the current database user has INSERT permission on qt_pricelists
func (r *PricelistRepository) CanWrite() bool {
	canWrite, _ := r.CanWriteDebug()
	return canWrite
}

// CanWriteDebug checks write permission and returns debug info
// Uses raw SQL with explicit columns to avoid schema mismatch issues
func (r *PricelistRepository) CanWriteDebug() (bool, string) {
	// Check if table exists first
	var count int64
	if err := r.db.Table("qt_pricelists").Count(&count).Error; err != nil {
		return false, fmt.Sprintf("table check failed: %v", err)
	}

	// Use raw SQL with only essential columns that always exist
	// This avoids GORM model validation and schema mismatch issues
	tx := r.db.Begin()
	if tx.Error != nil {
		return false, fmt.Sprintf("begin tx failed: %v", tx.Error)
	}
	defer tx.Rollback() // Always rollback - this is just a permission test

	testVersion := fmt.Sprintf("test-%06d", time.Now().Unix()%1000000)

	// Raw SQL insert with only core columns
	err := tx.Exec(`
		INSERT INTO qt_pricelists (version, created_by, is_active)
		VALUES (?, 'system', 1)
	`, testVersion).Error

	if err != nil {
		// Check if it's a permission error vs other errors
		errStr := err.Error()
		if strings.Contains(errStr, "INSERT command denied") ||
			strings.Contains(errStr, "Access denied") {
			return false, "no write permission"
		}
		return false, fmt.Sprintf("insert failed: %v", err)
	}

	return true, "ok"
}

// IncrementUsageCount increments the usage count for a pricelist
func (r *PricelistRepository) IncrementUsageCount(id uint) error {
	return r.db.Model(&models.Pricelist{}).Where("id = ?", id).
		UpdateColumn("usage_count", gorm.Expr("usage_count + 1")).Error
}

// DecrementUsageCount decrements the usage count for a pricelist
func (r *PricelistRepository) DecrementUsageCount(id uint) error {
	return r.db.Model(&models.Pricelist{}).Where("id = ?", id).
		UpdateColumn("usage_count", gorm.Expr("GREATEST(usage_count - 1, 0)")).Error
}

// GetExpiredUnused returns pricelists that are expired and unused
func (r *PricelistRepository) GetExpiredUnused() ([]models.Pricelist, error) {
	var pricelists []models.Pricelist
	if err := r.db.Where("expires_at < ? AND usage_count = 0", time.Now()).
		Find(&pricelists).Error; err != nil {
		return nil, fmt.Errorf("getting expired pricelists: %w", err)
	}
	return pricelists, nil
}