feat: cryptocurrency exchange added to casino

1 files changed, 78 insertions, 0 deletions

diff --git a/internal/cryptomarket/chart.go b/internal/cryptomarket/chart.go
new file mode 100644
index 0000000..c1fef29
--- /dev/null
+++ b/internal/cryptomarket/chart.go
@@ -0,0 +1,78 @@
+package cryptomarket
+
+import (
+	"fmt"
+	"math"
+	"strings"
+	"time"
+)
+
+// Chart uses one column per completed daily candle, auto-scales for BTC and
+// tiny tokens alike, and delegates color to the player's configured palette.
+func Chart(candles []Candle, width int, unicode bool, paint func(string, bool) string) []string {
+	width = max(12, min(80, width))
+	label := 12
+	count := width - label - 2
+	if count < 2 || len(candles) < 2 {
+		return []string{"Not enough completed daily candles."}
+	}
+	if len(candles) > count {
+		candles = candles[len(candles)-count:]
+	}
+	type bar struct{ o, h, l, c float64 }
+	bars := []bar{}
+	low, high := math.Inf(1), math.Inf(-1)
+	for _, c := range candles {
+		if c.Validate() != nil {
+			return []string{"Invalid candle history."}
+		}
+		o, _ := rat(c.Open).Float64()
+		h, _ := rat(c.High).Float64()
+		l, _ := rat(c.Low).Float64()
+		v, _ := rat(c.Close).Float64()
+		bars = append(bars, bar{o, h, l, v})
+		low = math.Min(low, l)
+		high = math.Max(high, h)
+	}
+	if high == low {
+		padding := math.Max(high*0.01, 1e-18)
+		low -= padding
+		high += padding
+	}
+	const height = 10
+	row := func(p float64) int { return max(0, min(height-1, int(math.Round((high-p)/(high-low)*(height-1))))) }
+	grid := make([][]string, height)
+	for y := range grid {
+		grid[y] = make([]string, len(bars))
+		for x := range grid[y] {
+			grid[y][x] = " "
+		}
+	}
+	wick, body, doji, axis := "|", "#", "-", "|"
+	if unicode {
+		wick, body, doji, axis = "│", "█", "━", "│"
+	}
+	for x, b := range bars {
+		top, bottom := min(row(b.o), row(b.c)), max(row(b.o), row(b.c))
+		for y := row(b.h); y <= row(b.l); y++ {
+			ch := wick
+			if y >= top && y <= bottom {
+				ch = body
+				if top == bottom {
+					ch = doji
+				}
+			}
+			if paint != nil {
+				ch = paint(ch, b.c >= b.o)
+			}
+			grid[y][x] = ch
+		}
+	}
+	out := []string{"USD / credits; daily candles (UTC). Up/down colored; body=open-close, wick=range."}
+	for y := range grid {
+		v := high - float64(y)*(high-low)/(height-1)
+		out = append(out, fmt.Sprintf("%11.5g %s%s", v, axis, strings.Join(grid[y], "")))
+	}
+	out = append(out, fmt.Sprintf("%s to %s", time.Unix(candles[0].Time, 0).UTC().Format("2006-01-02"), time.Unix(candles[len(candles)-1].Time, 0).UTC().Format("2006-01-02")))
+	return out
+}