package service

import (
	"errors"
	"fmt"
	"time"

	"gorm.io/gorm"
	"sql-platform/internal/model"
)

type TicketService struct {
	DB *gorm.DB
}

func NewTicketService(db *gorm.DB) *TicketService {
	return &TicketService{DB: db}
}

// CreateTicket creates a new ticket
func (s *TicketService) CreateTicket(ticket *model.Ticket) error {
	if ticket.TicketNo == "" {
		ticket.TicketNo = s.generateTicketNo()
	}
	if ticket.CreateTime.IsZero() {
		ticket.CreateTime = time.Now()
	}
	if ticket.Status == "" {
		ticket.Status = "pending"
	}
	return s.DB.Create(ticket).Error
}

// GetTicketByID retrieves a ticket by ID
func (s *TicketService) GetTicketByID(id uint) (*model.Ticket, error) {
	var ticket model.Ticket
	if err := s.DB.First(&ticket, id).Error; err != nil {
		return nil, errors.New("ticket not found")
	}
	return &ticket, nil
}

// ListTickets returns paginated tickets with filters
func (s *TicketService) ListTickets(page, pageSize int, status, priority string, applicantID uint) ([]model.Ticket, int64, error) {
	var tickets []model.Ticket
	var total int64

	db := s.DB.Model(&model.Ticket{})
	if status != "" {
		db = db.Where("status = ?", status)
	}
	if priority != "" {
		db = db.Where("priority = ?", priority)
	}
	if applicantID > 0 {
		db = db.Where("applicant_id = ?", applicantID)
	}

	db.Count(&total)
	offset := (page - 1) * pageSize
	if err := db.Offset(offset).Limit(pageSize).Order("create_time DESC").Find(&tickets).Error; err != nil {
		return nil, 0, err
	}

	return tickets, total, nil
}

// UpdateTicketStatus updates a ticket's status
func (s *TicketService) UpdateTicketStatus(id uint, status string, updaterID uint) error {
	updates := map[string]interface{}{
		"status": status,
	}
	now := time.Now()
	switch status {
	case "approved":
		updates["approver_id"] = updaterID
		updates["review_time"] = now
	case "executing", "completed", "failed":
		updates["execute_time"] = now
	}

	result := s.DB.Model(&model.Ticket{}).Where("id = ?", id).Updates(updates)
	if result.RowsAffected == 0 {
		return errors.New("ticket not found")
	}
	return result.Error
}

// ApproveTicket approves a ticket
func (s *TicketService) ApproveTicket(id, approverID uint, comment string) error {
	return s.UpdateTicketStatus(id, "approved", approverID)
}

// RejectTicket rejects a ticket
func (s *TicketService) RejectTicket(id, approverID uint, comment string) error {
	return s.UpdateTicketStatus(id, "rejected", approverID)
}

// GetTicketSQLItems returns SQL items for a ticket
func (s *TicketService) GetTicketSQLItems(ticketID uint) ([]model.TicketSQLItem, error) {
	var items []model.TicketSQLItem
	err := s.DB.Where("ticket_id = ?", ticketID).Order("seq ASC").Find(&items).Error
	return items, err
}

// CreateTicketSQLItem creates a SQL item for a ticket
func (s *TicketService) CreateTicketSQLItem(item *model.TicketSQLItem) error {
	return s.DB.Create(item).Error
}

// GetTicketApprovals returns approval records for a ticket
func (s *TicketService) GetTicketApprovals(ticketID uint) ([]model.TicketApproval, error) {
	var approvals []model.TicketApproval
	err := s.DB.Where("ticket_id = ?", ticketID).Order("step_number ASC").Find(&approvals).Error
	return approvals, err
}

// DeleteTicket soft-deletes a ticket
func (s *TicketService) DeleteTicket(id uint) error {
	return s.DB.Delete(&model.Ticket{}, id).Error
}

// generateTicketNo generates a unique ticket number
func (s *TicketService) generateTicketNo() string {
	now := time.Now()
	var count int64
	s.DB.Model(&model.Ticket{}).Where("DATE(create_time) = DATE(?)", now).Count(&count)
	return fmt.Sprintf("TK-%s-%04d", now.Format("20060102"), count+1)
}