// injbook prints a live Injective order book and what a taker order of a
// given size would cost against it.
//
//	go run ./cmd/injbook -market INJ/USDT -side buy -qty 250
package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"strings"
	"time"

	"github.com/edwardtay/injective-booklab/book"
	"github.com/edwardtay/injective-booklab/client"
	"github.com/edwardtay/injective-booklab/dec"
)

func main() {
	ticker := flag.String("market", "INJ/USDT", "market ticker, e.g. INJ/USDT or BTC/USDC PERP")
	sideS := flag.String("side", "buy", "buy or sell")
	qtyS := flag.String("qty", "100", "base quantity")
	depth := flag.Int("depth", 10, "levels to print per side")
	flag.Parse()

	side, err := book.ParseSide(*sideS)
	must(err)
	qty, err := dec.Parse(*qtyS)
	must(err)

	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()
	c := client.New()
	ms, err := c.Markets(ctx)
	must(err)
	var m *client.MarketInfo
	for i := range ms {
		if strings.EqualFold(ms[i].Ticker, *ticker) {
			m = &ms[i]
			break
		}
	}
	if m == nil {
		must(fmt.Errorf("market %q not found among %d active markets", *ticker, len(ms)))
	}
	snap, err := c.Orderbook(ctx, m.Kind, m.ID, 100)
	must(err)
	b := snap.Book
	mid, _ := b.Mid()
	spread, _ := b.SpreadBps()
	fmt.Printf("%s (%s) seq %d via %s in %dms\nmid %s  spread %s bps\n\n",
		m.Ticker, m.Kind, b.Seq, snap.Endpoint, snap.Ms, mid.Round(6), spread.Round(2))
	for i := min(*depth, len(b.Asks)) - 1; i >= 0; i-- {
		fmt.Printf("  ask %18s  %s\n", b.Asks[i].Price, b.Asks[i].Qty)
	}
	fmt.Println("  ----")
	for i := 0; i < min(*depth, len(b.Bids)); i++ {
		fmt.Printf("  bid %18s  %s\n", b.Bids[i].Price, b.Bids[i].Qty)
	}
	r := book.SimulateTaker(b, side, qty, dec.Zero(), m.TakerFee)
	fmt.Printf("\n%s %s: filled %s over %d levels, VWAP %s, worst %s, slippage %s bps, fee %s, unfilled %s\n",
		side, qty, r.Filled, r.LevelsUsed, r.VWAP.Round(6), r.WorstPrice, r.SlippageBps.Round(2), r.Fee.Round(6), r.Unfilled)
}

func must(err error) {
	if err != nil {
		fmt.Fprintln(os.Stderr, "injbook:", err)
		os.Exit(1)
	}
}