package service

import (
	"context"
	"spend-sparrow/internal/db"
	"spend-sparrow/internal/types"
	"time"

	"github.com/jmoiron/sqlx"
)

type Dashboard struct {
	db *sqlx.DB
}

func NewDashboard(db *sqlx.DB) *Dashboard {
	return &Dashboard{
		db: db,
	}
}

func (s Dashboard) MainChart(
	ctx context.Context,
	user *types.User,
) ([]types.DashboardMainChartEntry, error) {
	if user == nil {
		return nil, ErrUnauthorized
	}

	transactions := make([]types.Transaction, 0)
	err := s.db.SelectContext(ctx, &transactions, `
		SELECT *
		FROM "transaction" 
		WHERE user_id = ?
		ORDER BY timestamp`, user.Id)
	err = db.TransformAndLogDbError(ctx, "dashboard Chart", nil, err)
	if err != nil {
		return nil, err
	}

	timeEntries := make([]types.DashboardMainChartEntry, 0)
	var lastEntry *types.DashboardMainChartEntry
	for _, t := range transactions {
		if t.Error != nil {
			continue
		}

		newDay := t.Timestamp.Truncate(24 * time.Hour)
		if lastEntry == nil {
			lastEntry = &types.DashboardMainChartEntry{
				Day:     newDay,
				Value:   0,
				Savings: 0,
			}
		} else if lastEntry.Day != newDay {
			timeEntries = append(timeEntries, *lastEntry)
			lastEntry = &types.DashboardMainChartEntry{
				Day:     newDay,
				Value:   lastEntry.Value,
				Savings: lastEntry.Savings,
			}
		}

		if t.AccountId != nil {
			lastEntry.Value += t.Value
		}
		if t.TreasureChestId != nil {
			lastEntry.Savings += t.Value
		}
	}

	if lastEntry != nil {
		timeEntries = append(timeEntries, *lastEntry)
	}

	return timeEntries, nil
}