76 lines
1.5 KiB
Go
76 lines
1.5 KiB
Go
package prices
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"os"
|
|
"strings"
|
|
"time"
|
|
|
|
"github.com/shopspring/decimal"
|
|
)
|
|
|
|
type CoinPricesCache struct {
|
|
filename string
|
|
Prices map[string]decimal.Decimal
|
|
}
|
|
|
|
func NewCoinPricesCache(priceFile string) *CoinPricesCache {
|
|
return &CoinPricesCache{
|
|
filename: priceFile,
|
|
Prices: make(map[string]decimal.Decimal),
|
|
}
|
|
}
|
|
|
|
func (c *CoinPricesCache) GetPriceByTime(coingeckoID string, day time.Time) (decimal.Decimal, error) {
|
|
|
|
// remove hours and minutes,
|
|
// times are in UTC
|
|
day = time.Date(day.Year(), day.Month(), day.Day(), 0, 0, 0, 0, time.UTC)
|
|
|
|
// look up the price
|
|
key := fmt.Sprintf("%s%d", coingeckoID, day.UnixMilli())
|
|
if price, ok := c.Prices[key]; ok {
|
|
return price, nil
|
|
}
|
|
|
|
return decimal.NewFromInt(0), fmt.Errorf("price not found for %s", key)
|
|
}
|
|
|
|
// load the csv file with prices into a map
|
|
func (cpc *CoinPricesCache) InitCache() {
|
|
|
|
// open prices file
|
|
file := cpc.filename
|
|
f, err := os.Open(file)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
defer f.Close()
|
|
|
|
// read line by line
|
|
scanner := bufio.NewScanner(f)
|
|
for scanner.Scan() {
|
|
|
|
// split line by comma
|
|
row := scanner.Text()
|
|
tokens := strings.Split(row, ",")
|
|
if len(tokens) != 5 {
|
|
panic(fmt.Errorf("invalid line: %s", row))
|
|
}
|
|
|
|
// build map key: coingecko_id+timestamp
|
|
key := fmt.Sprintf("%s%s", tokens[1], tokens[3])
|
|
|
|
// parse price
|
|
price, err := decimal.NewFromString(tokens[4])
|
|
if err != nil {
|
|
msg := fmt.Sprintf("failed to parse price err=%v line=%s", err, row)
|
|
panic(msg)
|
|
}
|
|
|
|
cpc.Prices[key] = price
|
|
}
|
|
|
|
}
|