package service

import (
	"fmt"
	"mime/multipart"
	"os"
	"path"
	"strings"
	"time"

	"github.com/rovina/zsp-backend/internal/dto"
	"github.com/rovina/zsp-backend/internal/model"
	"github.com/rovina/zsp-backend/internal/repository"
)

type ZSPContractService interface {
	CreateFolder(req *dto.ZSPFolderCreateRequest) error
	GetFolders() ([]model.ZSPContractFolder, error)
	GetFolderById(folderID string) (*model.ZSPContractFolder, error)
	DeleteFolderById(folderID string) error
	UpdateFolderById(folderID string, req *dto.ZSPFolderUpdateRequest) error

	UploadContract(req *dto.ZSPContractCreateRequest, fileHeader *multipart.FileHeader) error
	GetContractById(contractID string) (*model.ZSPContractFile, error)
	GetContractWithDetails(contractID string) (*model.ZSPContractFile, error)
	ListContracts(folderID string) ([]model.ZSPContractFile, error)
	ListContractsWithDetails(folderID string) ([]model.ZSPContractFile, error)
	DeleteContractById(contractID string) error
	UpdateContract(contract *model.ZSPContractFile) error
	UpdateContractById(contractID string, req *dto.ZSPContractUpdateRequest) error

	// 合同详情相关
	CreateContractDetail(req *dto.ZSPContractDetailCreateRequest) error
	UpdateContractDetail(req *dto.ZSPContractDetailUpdateRequest) error
	GetContractDetailById(detailID string) (*model.ZSPContractDetail, error)
	ListContractDetails(contractFileID string) ([]model.ZSPContractDetail, error)
	DeleteContractDetailById(detailID string) error
	BatchCreateContractDetails(req *dto.ZSPContractDetailBatchCreateRequest) error
}

type zspContractService struct {
	repo repository.ZSPContractRepository
}

func NewZSPContractService(repo repository.ZSPContractRepository) (ZSPContractService, error) {
	return &zspContractService{repo: repo}, nil
}

func (s *zspContractService) CreateFolder(req *dto.ZSPFolderCreateRequest) error {
	var folder model.ZSPContractFolder
	folder.Name = req.Name
	folder.Description = req.Description
	folder.Count = 0
	folder.CreateTime = time.Now()

	return s.repo.CreateFolder(&folder)
}

func (s *zspContractService) GetFolders() ([]model.ZSPContractFolder, error) {
	folders, err := s.repo.GetFolders()
	if err != nil {
		return nil, err
	}
	return folders, nil
}

func (s *zspContractService) GetFolderById(folderID string) (*model.ZSPContractFolder, error) {
	return s.repo.GetFolderById(folderID)
}

func (s *zspContractService) DeleteFolderById(folderID string) error {
	return s.repo.DeleteFolderById(folderID)
}

func (s *zspContractService) UpdateFolderById(folderID string, req *dto.ZSPFolderUpdateRequest) error {
	folder, err := s.repo.GetFolderById(folderID)
	if err != nil {
		return err
	}

	folder.Name = req.Name
	folder.Description = req.Description
	return s.repo.UpdateFolder(folder)
}

func (s *zspContractService) UploadContract(req *dto.ZSPContractCreateRequest, fileHeader *multipart.FileHeader) error {
	timeNow := time.Now()
	var contract model.ZSPContractFile
	contract.FolderID = req.FolderID
	contract.Commodity = req.Commodity
	contract.CompanyName = req.CompanyName
	contract.ContractNumber = req.ContractNumber
	contract.ContractType = req.ContractType
	contract.FileName = fileHeader.Filename
	// 提取扩展名便于前端展示（如 pdf、jpg）
	if ext := path.Ext(fileHeader.Filename); ext != "" {
		contract.FileType = strings.TrimPrefix(strings.ToLower(ext), ".")
	} else {
		contract.FileType = fileHeader.Header.Get("Content-Type")
	}
	if req.SignDate == "" {
		return fmt.Errorf("签订日期为必填项")
	}
	signDate, err := time.Parse("2006-01-02", req.SignDate)
	if err != nil {
		return fmt.Errorf("签订日期格式不正确，请使用 YYYY-MM-DD: %w", err)
	}
	contract.SignDate = signDate
	contract.UploadTime = timeNow

	// 确保目录存在后保存文件
	saveDir := "./data/zsp-contract/files"
	if err := os.MkdirAll(saveDir, os.ModePerm); err != nil {
		return fmt.Errorf("create upload dir: %w", err)
	}
	storedName := fmt.Sprintf("%d_%s", timeNow.UnixNano(), fileHeader.Filename)
	savePath := path.Join(saveDir, storedName)

	if err := saveUploadedFile(fileHeader, savePath); err != nil {
		return err
	}
	contract.FileURL = "files/" + storedName
	contract.FileSize = fileHeader.Size
	return s.repo.CreateContract(&contract)
}

func (s *zspContractService) GetContractById(contractID string) (*model.ZSPContractFile, error) {
	return s.repo.GetContractById(contractID)
}

func (s *zspContractService) ListContracts(folderID string) ([]model.ZSPContractFile, error) {
	return s.repo.ListContracts(folderID)
}

func (s *zspContractService) DeleteContractById(contractID string) error {
	return s.repo.DeleteContractById(contractID)
}

func (s *zspContractService) UpdateContract(contract *model.ZSPContractFile) error {
	return s.repo.UpdateContract(contract)
}

func (s *zspContractService) UpdateContractById(contractID string, req *dto.ZSPContractUpdateRequest) error {
	contract, err := s.repo.GetContractById(contractID)
	if err != nil {
		return err
	}
	if req.ContractNumber != "" {
		contract.ContractNumber = req.ContractNumber
	}
	if req.CompanyName != "" {
		contract.CompanyName = req.CompanyName
	}
	if req.Commodity != "" {
		contract.Commodity = req.Commodity
	}
	if req.ContractType != "" {
		contract.ContractType = req.ContractType
	}
	if req.FolderID > 0 {
		contract.FolderID = req.FolderID
	}
	if req.SignDate != "" {
		signDate, err := time.Parse("2006-01-02", req.SignDate)
		if err != nil {
			return fmt.Errorf("签订日期格式不正确: %w", err)
		}
		contract.SignDate = signDate
	}
	return s.repo.UpdateContract(contract)
}

func (s *zspContractService) GetContractWithDetails(contractID string) (*model.ZSPContractFile, error) {
	contract, err := s.repo.GetContractById(contractID)
	if err != nil {
		return nil, err
	}
	// 获取详情列表
	details, err := s.repo.ListContractDetails(contractID)
	if err != nil {
		return nil, err
	}
	contract.Details = details
	return contract, nil
}

func (s *zspContractService) ListContractsWithDetails(folderID string) ([]model.ZSPContractFile, error) {
	return s.repo.ListContractsWithDetails(folderID)
}

// ============ 合同详情相关方法 ============

func (s *zspContractService) CreateContractDetail(req *dto.ZSPContractDetailCreateRequest) error {
	var detail model.ZSPContractDetail
	detail.ContractFileID = req.ContractFileID
	detail.CommodityName = req.CommodityName
	detail.CommodityCode = req.CommodityCode
	detail.TotalQuantity = req.TotalQuantity
	detail.Unit = req.Unit
	detail.UnitPrice = req.UnitPrice
	detail.DeliveredQty = req.DeliveredQty
	detail.BillOfLading = req.BillOfLading
	detail.Remark = req.Remark

	// PendingQty 会在 BeforeCreate 钩子中自动计算
	return s.repo.CreateContractDetail(&detail)
}

func (s *zspContractService) UpdateContractDetail(req *dto.ZSPContractDetailUpdateRequest) error {
	detail, err := s.repo.GetContractDetailById(fmt.Sprintf("%d", req.ID))
	if err != nil {
		return err
	}

	if req.CommodityName != "" {
		detail.CommodityName = req.CommodityName
	}
	if req.CommodityCode != "" {
		detail.CommodityCode = req.CommodityCode
	}
	if req.TotalQuantity > 0 {
		detail.TotalQuantity = req.TotalQuantity
	}
	if req.Unit != "" {
		detail.Unit = req.Unit
	}
	if req.UnitPrice > 0 {
		detail.UnitPrice = req.UnitPrice
	}
	// DeliveredQty 可以为 0，所以需要特别处理
	detail.DeliveredQty = req.DeliveredQty
	if req.BillOfLading != "" {
		detail.BillOfLading = req.BillOfLading
	}
	detail.Remark = req.Remark

	// PendingQty 会在 BeforeUpdate 钩子中自动计算
	return s.repo.UpdateContractDetail(detail)
}

func (s *zspContractService) GetContractDetailById(detailID string) (*model.ZSPContractDetail, error) {
	return s.repo.GetContractDetailById(detailID)
}

func (s *zspContractService) ListContractDetails(contractFileID string) ([]model.ZSPContractDetail, error) {
	return s.repo.ListContractDetails(contractFileID)
}

func (s *zspContractService) DeleteContractDetailById(detailID string) error {
	return s.repo.DeleteContractDetailById(detailID)
}

func (s *zspContractService) BatchCreateContractDetails(req *dto.ZSPContractDetailBatchCreateRequest) error {
	details := make([]model.ZSPContractDetail, 0, len(req.Details))
	for _, detailReq := range req.Details {
		detail := model.ZSPContractDetail{
			ContractFileID: req.ContractFileID,
			CommodityName:  detailReq.CommodityName,
			CommodityCode:  detailReq.CommodityCode,
			TotalQuantity:  detailReq.TotalQuantity,
			Unit:           detailReq.Unit,
			UnitPrice:      detailReq.UnitPrice,
			DeliveredQty:    detailReq.DeliveredQty,
			BillOfLading:    detailReq.BillOfLading,
			Remark:          detailReq.Remark,
		}
		// PendingQty 会在 BeforeCreate 钩子中自动计算
		details = append(details, detail)
	}
	return s.repo.BatchCreateContractDetails(details)
}