package processor

import (
	"context"
	"fmt"
	"time"

	"apskel-pos-be/internal/entities"
	"apskel-pos-be/internal/mappers"
	"apskel-pos-be/internal/models"

	"github.com/google/uuid"
)

type ExpenseProcessor interface {
	CreateExpense(ctx context.Context, organizationID uuid.UUID, req *models.CreateExpenseRequest) (*models.ExpenseResponse, error)
	UpdateExpense(ctx context.Context, id, organizationID uuid.UUID, req *models.UpdateExpenseRequest) (*models.ExpenseResponse, error)
	DeleteExpense(ctx context.Context, id, organizationID uuid.UUID) error
	GetExpenseByID(ctx context.Context, id, organizationID uuid.UUID) (*models.ExpenseResponse, error)
	ListExpenses(ctx context.Context, organizationID uuid.UUID, filters map[string]interface{}, page, limit int) ([]*models.ExpenseResponse, int, error)
}

type ExpenseProcessorImpl struct {
	expenseRepo ExpenseRepository
}

func NewExpenseProcessorImpl(expenseRepo ExpenseRepository) *ExpenseProcessorImpl {
	return &ExpenseProcessorImpl{
		expenseRepo: expenseRepo,
	}
}

func (p *ExpenseProcessorImpl) CreateExpense(ctx context.Context, organizationID uuid.UUID, req *models.CreateExpenseRequest) (*models.ExpenseResponse, error) {
	outletID, err := uuid.Parse(req.OutletID)
	if err != nil {
		return nil, fmt.Errorf("invalid outlet_id: %w", err)
	}

	transactionDate, err := time.Parse("2006-01-02", req.TransactionDate)
	if err != nil {
		return nil, fmt.Errorf("invalid transaction_date format, expected YYYY-MM-DD: %w", err)
	}

	expenseEntity := &entities.Expense{
		OrganizationID:  organizationID,
		OutletID:        outletID,
		Receiver:        req.Receiver,
		TransactionDate: transactionDate,
		CodeNumber:      req.CodeNumber,
		Description:     req.Description,
		Tax:             req.Tax,
		Total:           req.Total,
	}

	err = p.expenseRepo.Create(ctx, expenseEntity)
	if err != nil {
		return nil, fmt.Errorf("failed to create expense: %w", err)
	}

	for _, itemReq := range req.Items {
		chartOfAccountID, err := uuid.Parse(itemReq.ChartOfAccountID)
		if err != nil {
			return nil, fmt.Errorf("invalid chart_of_account_id for item: %w", err)
		}

		itemEntity := &entities.ExpenseItem{
			ExpenseID:        expenseEntity.ID,
			ChartOfAccountID: chartOfAccountID,
			Item:             itemReq.Item,
			Description:      itemReq.Description,
			Amount:           itemReq.Amount,
		}

		err = p.expenseRepo.CreateItem(ctx, itemEntity)
		if err != nil {
			return nil, fmt.Errorf("failed to create expense item: %w", err)
		}
	}

	created, err := p.expenseRepo.GetByID(ctx, expenseEntity.ID)
	if err != nil {
		return mappers.ExpenseEntityToResponse(expenseEntity), nil
	}

	return mappers.ExpenseEntityToResponse(created), nil
}

func (p *ExpenseProcessorImpl) UpdateExpense(ctx context.Context, id, organizationID uuid.UUID, req *models.UpdateExpenseRequest) (*models.ExpenseResponse, error) {
	expenseEntity, err := p.expenseRepo.GetByIDAndOrganizationID(ctx, id, organizationID)
	if err != nil {
		return nil, fmt.Errorf("expense not found: %w", err)
	}

	if req.Receiver != nil {
		expenseEntity.Receiver = *req.Receiver
	}
	if req.TransactionDate != nil {
		parsedDate, err := time.Parse("2006-01-02", *req.TransactionDate)
		if err != nil {
			return nil, fmt.Errorf("invalid transaction_date format, expected YYYY-MM-DD: %w", err)
		}
		expenseEntity.TransactionDate = parsedDate
	}
	if req.CodeNumber != nil {
		expenseEntity.CodeNumber = *req.CodeNumber
	}
	if req.OutletID != nil {
		outletID, err := uuid.Parse(*req.OutletID)
		if err != nil {
			return nil, fmt.Errorf("invalid outlet_id: %w", err)
		}
		expenseEntity.OutletID = outletID
	}
	if req.Description != nil {
		expenseEntity.Description = req.Description
	}
	if req.Tax != nil {
		expenseEntity.Tax = *req.Tax
	}
	if req.Total != nil {
		expenseEntity.Total = *req.Total
	}
	if req.Reserved1 != nil {
		expenseEntity.Reserved1 = req.Reserved1
	}

	if req.Items != nil {
		err = p.expenseRepo.DeleteItemsByExpenseID(ctx, expenseEntity.ID)
		if err != nil {
			return nil, fmt.Errorf("failed to delete existing items: %w", err)
		}

		for _, itemReq := range req.Items {
			chartOfAccountID := uuid.Nil
			if itemReq.ChartOfAccountID != nil {
				chartOfAccountID, err = uuid.Parse(*itemReq.ChartOfAccountID)
				if err != nil {
					return nil, fmt.Errorf("invalid chart_of_account_id for item: %w", err)
				}
			}

			amount := 0.0
			if itemReq.Amount != nil {
				amount = *itemReq.Amount
			}
			item := ""
			if itemReq.Item != nil {
				item = *itemReq.Item
			}

			itemEntity := &entities.ExpenseItem{
				ExpenseID:        expenseEntity.ID,
				ChartOfAccountID: chartOfAccountID,
				Item:             item,
				Description:      itemReq.Description,
				Amount:           amount,
			}

			err = p.expenseRepo.CreateItem(ctx, itemEntity)
			if err != nil {
				return nil, fmt.Errorf("failed to create expense item: %w", err)
			}
		}
	}

	err = p.expenseRepo.Update(ctx, expenseEntity)
	if err != nil {
		return nil, fmt.Errorf("failed to update expense: %w", err)
	}

	updated, err := p.expenseRepo.GetByID(ctx, id)
	if err != nil {
		return mappers.ExpenseEntityToResponse(expenseEntity), nil
	}

	return mappers.ExpenseEntityToResponse(updated), nil
}

func (p *ExpenseProcessorImpl) DeleteExpense(ctx context.Context, id, organizationID uuid.UUID) error {
	_, err := p.expenseRepo.GetByIDAndOrganizationID(ctx, id, organizationID)
	if err != nil {
		return fmt.Errorf("expense not found: %w", err)
	}

	err = p.expenseRepo.Delete(ctx, id)
	if err != nil {
		return fmt.Errorf("failed to delete expense: %w", err)
	}

	return nil
}

func (p *ExpenseProcessorImpl) GetExpenseByID(ctx context.Context, id, organizationID uuid.UUID) (*models.ExpenseResponse, error) {
	expenseEntity, err := p.expenseRepo.GetByIDAndOrganizationID(ctx, id, organizationID)
	if err != nil {
		return nil, fmt.Errorf("expense not found: %w", err)
	}

	return mappers.ExpenseEntityToResponse(expenseEntity), nil
}

func (p *ExpenseProcessorImpl) ListExpenses(ctx context.Context, organizationID uuid.UUID, filters map[string]interface{}, page, limit int) ([]*models.ExpenseResponse, int, error) {
	offset := (page - 1) * limit
	expenseEntities, total, err := p.expenseRepo.List(ctx, organizationID, filters, limit, offset)
	if err != nil {
		return nil, 0, fmt.Errorf("failed to list expenses: %w", err)
	}

	expenseResponses := mappers.ExpenseEntitiesToResponses(expenseEntities)
	totalPages := int((total + int64(limit) - 1) / int64(limit))

	return expenseResponses, totalPages, nil
}