package fba

import (
	"testing"

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

var D = dec.MustParse

func lv(p, q string) book.Level { return book.Level{Price: D(p), Qty: D(q)} }

// Fixture: the "Market Order Matching" worked example in the Injective API docs.
func TestClearMarketDocsExample(t *testing.T) {
	start := &book.Book{
		Asks: []book.Level{lv("64360", "0.5"), lv("64370", "0.2"), lv("64390", "0.3")},
		Bids: []book.Level{lv("64210", "0.1"), lv("64205", "0.4"), lv("64200", "0.2")},
	}
	buys := ClearMarket(start, book.Buy, []Order{
		{ID: "mb1", Price: D("64360"), Qty: D("0.2")},
		{ID: "mb2", Price: D("66000"), Qty: D("0.4")},
	})
	if buys.Matched.String() != "0.5" || buys.ClearingPrice.String() != "64360" {
		t.Fatalf("buys matched %s at %s, docs say 0.5 at 64360", buys.Matched, buys.ClearingPrice)
	}
	// Highest worst-price first: mb2 fills 0.4, mb1 gets 0.1 and 0.1 is cancelled.
	if buys.Orders[0].ID != "mb2" || buys.Orders[1].Cancelled.String() != "0.1" {
		t.Errorf("order priority wrong: %+v", buys.Orders)
	}

	sells := ClearMarket(start, book.Sell, []Order{
		{ID: "ms1", Price: D("60000"), Qty: D("0.1")},
		{ID: "ms2", Price: D("61000"), Qty: D("0.2")},
		{ID: "ms3", Price: D("69000"), Qty: D("0.3")},
	})
	if sells.Matched.String() != "0.3" {
		t.Fatalf("sells matched %s, docs say 0.3", sells.Matched)
	}
	// (64210*0.1 + 64205*0.2) / 0.3 = 64206.666...
	if got := sells.ClearingPrice.Round(2).String(); got != "64206.67" {
		t.Errorf("sell clearing price %s, docs say 64206.67", got)
	}
	if sells.Orders[2].ID != "ms3" || sells.Orders[2].Cancelled.String() != "0.3" {
		t.Errorf("ms3 should be cancelled in full: %+v", sells.Orders[2])
	}
}

// Fixture: the "Limit Order Matching" worked example in the same docs.
func TestClearLimitDocsExample(t *testing.T) {
	rest := &book.Book{
		Asks: []book.Level{lv("64250", "0.5"), lv("64370", "0.2"), lv("64390", "0.3")},
		Bids: []book.Level{lv("64210", "0.1"), lv("64205", "0.3"), lv("64200", "0.2")},
	}
	orders := []Order{
		{ID: "ls1", Side: book.Sell, Price: D("64220"), Qty: D("0.4")},
		{ID: "ls2", Side: book.Sell, Price: D("64180"), Qty: D("0.2")},
		{ID: "lb1", Side: book.Buy, Price: D("64370"), Qty: D("0.4")},
		{ID: "lb2", Side: book.Buy, Price: D("64360"), Qty: D("0.2")},
	}
	r := ClearLimit(rest, orders, dec.Zero())
	if r.LastSell.String() != "64220" || r.LastBuy.String() != "64360" {
		t.Fatalf("range [%s, %s], docs say [64220, 64360]", r.LastSell, r.LastBuy)
	}
	if r.ClearingPrice.String() != "64230" {
		t.Errorf("clearing %s, docs say resting mid 64230", r.ClearingPrice)
	}
	if err := r.After.Validate(); err != nil {
		t.Errorf("book after the auction is invalid: %v", err)
	}
	// Mark price outside the range clamps to the nearer bound.
	if p := ClearLimit(rest, orders, D("64500")).ClearingPrice.String(); p != "64360" {
		t.Errorf("mark above range should clear at last buy, got %s", p)
	}
	if p := ClearLimit(rest, orders, D("64300")).ClearingPrice.String(); p != "64300" {
		t.Errorf("mark inside range should be used, got %s", p)
	}
}

func TestNoCrossNoMatch(t *testing.T) {
	rest := &book.Book{Asks: []book.Level{lv("10", "1")}, Bids: []book.Level{lv("9", "1")}}
	r := ClearLimit(rest, []Order{{ID: "b", Side: book.Buy, Price: D("9.5"), Qty: D("2")}}, dec.Zero())
	if !r.Matched.IsZero() || r.Orders[0].Rests.String() != "2" {
		t.Fatalf("non-crossing order should rest: %+v", r)
	}
}