package game_test

import (
	"testing"

	"github.com/iliadenisov/galaxy/internal/model/game"
	"github.com/stretchr/testify/assert"
)

var (
	attacker = game.ShipType{
		ShipTypeReport: game.ShipTypeReport{
			Name:     "Attacker",
			Drive:    8,
			Armament: 1,
			Weapons:  8,
			Shields:  8,
			Cargo:    0,
		},
	}
	defender = game.ShipType{
		ShipTypeReport: game.ShipTypeReport{
			Name:     "Defender",
			Drive:    1,
			Armament: 1,
			Weapons:  1,
			Shields:  1,
			Cargo:    0,
		},
	}
	ship = game.ShipType{
		ShipTypeReport: game.ShipTypeReport{
			Name:     "Ship",
			Drive:    10,
			Armament: 1,
			Weapons:  10,
			Shields:  10,
			Cargo:    0,
		},
	}
)

func TestDestroyProbability(t *testing.T) {
	probability := game.DestroyProbability(ship.Weapons, 1, ship.Shields, 1, ship.EmptyMass())
	assert.Equal(t, .5, probability)

	unsinkableShip := ship
	unsinkableShip.Shields = 55
	probability = game.DestroyProbability(ship.Weapons, 1, unsinkableShip.Shields, 1, unsinkableShip.EmptyMass())
	assert.LessOrEqual(t, probability, 0.)

	disruptiveShip := ship
	disruptiveShip.Weapons = 40
	probability = game.DestroyProbability(disruptiveShip.Weapons, 1, ship.Shields, 1, ship.EmptyMass())
	assert.GreaterOrEqual(t, probability, 1.)
}

func TestEffectiveDefence(t *testing.T) {
	assert.Equal(t, 10., game.EffectiveDefence(ship.Shields, 1, ship.EmptyMass()))

	attackerEffectiveDefence := game.EffectiveDefence(attacker.Shields, 1, attacker.EmptyMass())
	defenderEffectiveDefence := game.EffectiveDefence(defender.Shields, 1, defender.EmptyMass())

	// attacker's effective shields must be 'just' 4 times greater than defender's
	assert.InDelta(t, defenderEffectiveDefence*4, attackerEffectiveDefence, 0)
}