wip

ledger/predict.go

@@ -0,0 +1,68 @@
+package ledger
+
+import (
+	"fmt"
+	"io"
+	"log"
+	"maps"
+	"time"
+)
+
+func RegisterWithContributionPrediction(reg map[string]Balances, windowAsPercentOfTotalDuration float64) (map[string]Balances, error) {
+	return reg, io.EOF
+}
+
+func BPIWithFixedGrowthPrediction(reg map[string]Balances, windowAsPercentOfTotalDuration float64, pattern string, rate float64) (map[string]Balances, error) {
+	result := make(map[string]Balances)
+	return result, io.EOF
+}
+
+func RegisterWithCompoundingInterestPrediction(reg map[string]Balances, windowAsPercentOfTotalDuration float64, pattern string, rate float64) (map[string]Balances, error) {
+	nameToLastDate := func() map[string]string {
+		result := map[string]string{}
+		for date, balances := range reg {
+			for name := range balances {
+				if result[name] < date {
+					result[name] = date
+				}
+			}
+		}
+		return result
+	}()
+	firstTime, lastTime := func() (time.Time, time.Time) {
+		var latest time.Time
+		first := time.Now()
+		for _, v := range nameToLastDate {
+			v2, _ := dateToTime(v)
+			if latest.Before(v2) {
+				latest = v2
+			}
+			if first.Before(v2) {
+				first = v2
+			}
+		}
+		return first, latest
+	}()
+	log.Println("first", firstTime, "last time", lastTime, "nameToDate", nameToLastDate)
+
+	lastPrediction := lastTime
+	for lastPrediction.Before(lastTime.Add(lastTime.Sub(firstTime) * time.Duration(windowAsPercentOfTotalDuration))) {
+		lastPrediction = lastPrediction.Add(time.Hour * 24 * (45 - lastPrediction.Day()))
+      TODO ^
+	}
+
+	result := maps.Clone(reg)
+	return result, io.EOF
+}
+
+func dateToTime(s string) (time.Time, error) {
+	for _, layout := range []string{
+		"2006-01-02",
+		"2006-01",
+	} {
+		if t, err := time.ParseInLocation(layout, s, time.Local); err == nil {
+			return t, err
+		}
+	}
+	return time.Time{}, fmt.Errorf("no layout matching %q", s)
+}