crypto_print.py

#!/usr/bin/env python3
"""Print a cryptocurrency ticker with a 7-day chart on the S01 printer.

Pulls live price, 24h/7d change, and a week of price history from CoinGecko, and
draws the history as a line chart above the stats.

Examples:
    python crypto_print.py                  # Bitcoin
    python crypto_print.py --coin ethereum
    python crypto_print.py --coin sol       # symbol aliases work too
    python crypto_print.py --no-print
"""
from __future__ import annotations

import argparse
from datetime import datetime
from pathlib import Path

from PIL import Image, ImageDraw

from print_common import ROOT, Card, font, get_json

API = "https://api.coingecko.com/api/v3"
ALIASES = {"btc": "bitcoin", "eth": "ethereum", "sol": "solana", "doge": "dogecoin",
           "ada": "cardano", "xrp": "ripple", "bnb": "binancecoin", "ltc": "litecoin"}


def fmt_price(p: float) -> str:
    if p >= 100:
        return f"${p:,.0f}"
    if p >= 1:
        return f"${p:,.2f}"
    return f"${p:.6f}".rstrip("0")


def draw_chart(prices: list[float], w: int, h: int = 150) -> Image.Image:
    img = Image.new("L", (w, h), 255)
    d = ImageDraw.Draw(img)
    lo, hi = min(prices), max(prices)
    span = (hi - lo) or 1
    n = len(prices)
    pad = 4
    pts = [(pad + i / (n - 1) * (w - 2 * pad), pad + (1 - (p - lo) / span) * (h - 2 * pad))
           for i, p in enumerate(prices)]
    d.line(pts, fill=0, width=2, joint="curve")
    # baseline at the starting price (dotted) to show net move
    y0 = pad + (1 - (prices[0] - lo) / span) * (h - 2 * pad)
    for x in range(0, w, 6):
        d.point((x, y0), fill=0)
    # mark the latest point
    lx, ly = pts[-1]
    d.ellipse((lx - 3, ly - 3, lx + 3, ly + 3), fill=0)
    tiny = font(False, 11)
    d.text((pad, pad), fmt_price(hi), fill=0, font=tiny)
    d.text((pad, h - 16), fmt_price(lo), fill=0, font=tiny)
    return img


def main() -> int:
    parser = argparse.ArgumentParser(description="Print a crypto ticker with a 7-day chart on the S01 printer.")
    parser.add_argument("--coin", default="bitcoin", help="CoinGecko id or common symbol (default: bitcoin).")
    parser.add_argument("--out", type=Path, default=ROOT / "crypto.png")
    parser.add_argument("--darkness", type=int, choices=range(1, 6), default=3)
    parser.add_argument("--bottom-feed", type=int, default=24)
    parser.add_argument("--no-print", action="store_true")
    args = parser.parse_args()

    coin = ALIASES.get(args.coin.lower(), args.coin.lower())
    print(f"Fetching {coin} ...")
    markets = get_json(f"{API}/coins/markets?vs_currency=usd&ids={coin}&price_change_percentage=24h,7d")
    if not markets:
        raise SystemExit(f"No coin '{coin}' on CoinGecko (try the full id, e.g. 'ethereum')")
    c = markets[0]
    prices = [p[1] for p in get_json(f"{API}/coins/{coin}/market_chart?vs_currency=usd&days=7")["prices"]]

    ch24 = c.get("price_change_percentage_24h") or 0
    ch7 = c.get("price_change_percentage_7d_in_currency") or 0
    sign = lambda v: f"+{v:.1f}%" if v >= 0 else f"{v:.1f}%"  # noqa: E731
    print(f"  {c['name']} {fmt_price(c['current_price'])}  24h {sign(ch24)}")

    card = Card()
    card.title(f"{c['name'].upper()}  {c['symbol'].upper()}")
    card.heading(fmt_price(c["current_price"]), size=30)
    card.line(f"24h {sign(ch24)}    7d {sign(ch7)}", size=14, bold=True, center=True)
    card.gap(4).image(draw_chart(prices, card.inner_w), border=True)
    card.line("7-day price", size=11, bold=False, center=True)
    card.gap(2).divider()
    card.kv("Rank", f"#{c.get('market_cap_rank', '?')}")
    card.kv("24h High", fmt_price(c["high_24h"]))
    card.kv("24h Low", fmt_price(c["low_24h"]))
    card.kv("All-time high", fmt_price(c["ath"]))
    card.kv("Market cap", f"${c['market_cap'] / 1e9:.1f}B")
    card.footer("coingecko.com", datetime.now().strftime("%Y-%m-%d %H:%M"))
    return card.finish(args.out, args.bottom_feed, args.darkness, do_print=not args.no_print)


if __name__ == "__main__":
    raise SystemExit(main())