Portfolio-Engine/internal/service/portfolio.go

package service

import (
	"Portifolio/internal/database"
	"Portifolio/internal/model"
	"encoding/json"
	"fmt"
	"net/http"

	_ "github.com/mattn/go-sqlite3"
)

func (s *Service) UpdatePositionByTradeList() error {

	trades, err := database.GetTrades(s.db)
	if err != nil {
		fmt.Printf("Failed to get the trades from db: %s", err)
	}

	TradeSum := make(map[string]model.Position)

	for _, trade := range trades {
		if trade.Type == model.BuyType {
			TradeSum[trade.Symbol] = model.Position{
				Symbol:       trade.Symbol,
				CurrencyCode: trade.CurrencyCode,
				CostBasis:    TradeSum[trade.Symbol].CostBasis + trade.Price,
				Shares:       TradeSum[trade.Symbol].Shares + trade.Shares,
			}
		} else {
			TradeSum[trade.Symbol] = model.Position{
				Symbol:       trade.Symbol,
				CurrencyCode: trade.CurrencyCode,
				CostBasis:    TradeSum[trade.Symbol].CostBasis - trade.Price,
				Shares:       TradeSum[trade.Symbol].Shares - trade.Shares,
			}
		}

	}

	var NewPositinos []model.Position
	for _, pos := range TradeSum {
		NewPositinos = append(NewPositinos, pos)
	}

	err = database.UpdatePositions(s.db, NewPositinos)
	if err != nil {
		return fmt.Errorf("Failed to insert the new postions number into db: %s", err)
	}

	return nil
}

func (s *Service) AddTradeHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req model.AddTradeRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			http.Error(w, "invalid json", http.StatusBadRequest)
			return
		}

		if err := req.Validate(); err != nil {
			http.Error(w, fmt.Sprintf("failed to validate trade: %s", err), http.StatusBadRequest)
			return
		}

		currency, err := database.GetCurrencyByCode(s.db, req.CurrencyCode)
		if err != nil {
			http.Error(w, fmt.Sprintf("failed to find currency: %s", err), http.StatusInternalServerError)
			return
		}

		switch model.TradeType(req.Type) {
		case model.DividendType:
			dividend, err := req.ToDividend()
			if err != nil {
				http.Error(w, fmt.Sprintf("failed to build dividend: %s", err), http.StatusBadRequest)
				return
			}
			dividend.CurrencyCode = currency.Code

			if err := database.InsertDividend(s.db, dividend); err != nil {
				http.Error(w, fmt.Sprintf("failed to insert dividend: %s", err), http.StatusInternalServerError)
				return
			}

			w.Header().Set("Content-Type", "application/json")
			json.NewEncoder(w).Encode(map[string]any{"success": true})

		case model.BuyType, model.SellType:
			trade, err := req.ToTrade()
			if err != nil {
				http.Error(w, fmt.Sprintf("failed to build trade: %s", err), http.StatusBadRequest)
				return
			}
			trade.CurrencyCode = currency.Code

			if err := database.InsertTrade(s.db, trade); err != nil {
				http.Error(w, fmt.Sprintf("failed to insert trade: %s", err), http.StatusInternalServerError)
				return
			}

			update := true
			if err := s.UpdatePositionByTradeList(); err != nil {
				update = false
			}

			w.Header().Set("Content-Type", "application/json")
			json.NewEncoder(w).Encode(map[string]any{"success": true, "position_update": update})

		default:
			http.Error(w, fmt.Sprintf("unknown trade type: %d", req.Type), http.StatusBadRequest)
		}
	}
}

func (s *Service) GetTrades() ([]model.Trade, error) {
	TradeList, err := database.GetTrades(s.db)
	return TradeList, err
}

func (s *Service) GetTradeListHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		tradeList, err := database.GetTrades(s.db)
		if err != nil {
			http.Error(w, fmt.Sprintf("failed to fetch trades: %s", err), http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		if err := json.NewEncoder(w).Encode(tradeList); err != nil {
			http.Error(w, fmt.Sprintf("failed to encode trades: %s", err), http.StatusInternalServerError)
			return
		}
	}
}

func (s *Service) GetPositions() ([]model.Position, error) {
	posList, err := database.GetPositions(s.db)
	return posList, err
}

func (s *Service) GetPositionListHandler() http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		posList, err := database.GetPositions(s.db)
		if err != nil {
			http.Error(w, fmt.Sprintf("failed to fetch postiton: %s", err), http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		if err := json.NewEncoder(w).Encode(posList); err != nil {
			http.Error(w, fmt.Sprintf("failed to encode positions: %s", err), http.StatusInternalServerError)
			return
		}
	}
}