package contract_test

import (
	"math/big"
	"path/filepath"
	"testing"

	"github.com/nspcc-dev/neo-go/internal/contracts"
	"github.com/nspcc-dev/neo-go/internal/random"
	"github.com/nspcc-dev/neo-go/pkg/core/block"
	"github.com/nspcc-dev/neo-go/pkg/core/interop"
	"github.com/nspcc-dev/neo-go/pkg/core/interop/contract"
	"github.com/nspcc-dev/neo-go/pkg/core/native"
	"github.com/nspcc-dev/neo-go/pkg/core/transaction"
	"github.com/nspcc-dev/neo-go/pkg/neotest/chain"
	"github.com/nspcc-dev/neo-go/pkg/smartcontract/callflag"
	"github.com/nspcc-dev/neo-go/pkg/smartcontract/trigger"
	"github.com/nspcc-dev/neo-go/pkg/util"
	"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
	"github.com/nspcc-dev/neo-go/pkg/vm/stackitem"
	"github.com/stretchr/testify/require"
)

var pathToInternalContracts = filepath.Join("..", "..", "..", "..", "internal", "contracts")

func TestGetCallFlags(t *testing.T) {
	bc, _ := chain.NewSingle(t)
	ic := bc.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})

	ic.VM.LoadScriptWithHash([]byte{byte(opcode.RET)}, util.Uint160{1, 2, 3}, callflag.All)
	require.NoError(t, contract.GetCallFlags(ic))
	require.Equal(t, int64(callflag.All), ic.VM.Estack().Pop().Value().(*big.Int).Int64())
}

func TestCall(t *testing.T) {
	bc, _ := chain.NewSingle(t)
	ic := bc.GetTestVM(trigger.Application, &transaction.Transaction{}, &block.Block{})

	cs, currCs := contracts.GetTestContractState(t, pathToInternalContracts, 4, 5, random.Uint160()) // sender and IDs are not important for the test
	require.NoError(t, native.PutContractState(ic.DAO, cs))
	require.NoError(t, native.PutContractState(ic.DAO, currCs))

	currScript := currCs.NEF.Script
	h := cs.Hash

	addArgs := stackitem.NewArray([]stackitem.Item{stackitem.Make(1), stackitem.Make(2)})
	t.Run("Good", func(t *testing.T) {
		t.Run("2 arguments", func(t *testing.T) {
			loadScript(ic, currScript, 42)
			ic.VM.Estack().PushVal(addArgs)
			ic.VM.Estack().PushVal(callflag.All)
			ic.VM.Estack().PushVal("add")
			ic.VM.Estack().PushVal(h.BytesBE())
			require.NoError(t, contract.Call(ic))
			require.NoError(t, ic.VM.Run())
			require.Equal(t, 2, ic.VM.Estack().Len())
			require.Equal(t, big.NewInt(3), ic.VM.Estack().Pop().Value())
			require.Equal(t, big.NewInt(42), ic.VM.Estack().Pop().Value())
		})
		t.Run("3 arguments", func(t *testing.T) {
			loadScript(ic, currScript, 42)
			ic.VM.Estack().PushVal(stackitem.NewArray(
				append(addArgs.Value().([]stackitem.Item), stackitem.Make(3))))
			ic.VM.Estack().PushVal(callflag.All)
			ic.VM.Estack().PushVal("add")
			ic.VM.Estack().PushVal(h.BytesBE())
			require.NoError(t, contract.Call(ic))
			require.NoError(t, ic.VM.Run())
			require.Equal(t, 2, ic.VM.Estack().Len())
			require.Equal(t, big.NewInt(6), ic.VM.Estack().Pop().Value())
			require.Equal(t, big.NewInt(42), ic.VM.Estack().Pop().Value())
		})
	})

	t.Run("CallExInvalidFlag", func(t *testing.T) {
		loadScript(ic, currScript, 42)
		ic.VM.Estack().PushVal(addArgs)
		ic.VM.Estack().PushVal(byte(0xFF))
		ic.VM.Estack().PushVal("add")
		ic.VM.Estack().PushVal(h.BytesBE())
		require.Error(t, contract.Call(ic))
	})

	runInvalid := func(args ...interface{}) func(t *testing.T) {
		return func(t *testing.T) {
			loadScriptWithHashAndFlags(ic, currScript, h, callflag.All, 42)
			for i := range args {
				ic.VM.Estack().PushVal(args[i])
			}
			// interops can both return error and panic,
			// we don't care which kind of error has occurred
			require.Panics(t, func() {
				err := contract.Call(ic)
				if err != nil {
					panic(err)
				}
			})
		}
	}

	t.Run("Invalid", func(t *testing.T) {
		t.Run("Hash", runInvalid(addArgs, "add", h.BytesBE()[1:]))
		t.Run("MissingHash", runInvalid(addArgs, "add", util.Uint160{}.BytesBE()))
		t.Run("Method", runInvalid(addArgs, stackitem.NewInterop("add"), h.BytesBE()))
		t.Run("MissingMethod", runInvalid(addArgs, "sub", h.BytesBE()))
		t.Run("DisallowedMethod", runInvalid(stackitem.NewArray(nil), "ret7", h.BytesBE()))
		t.Run("Arguments", runInvalid(1, "add", h.BytesBE()))
		t.Run("NotEnoughArguments", runInvalid(
			stackitem.NewArray([]stackitem.Item{stackitem.Make(1)}), "add", h.BytesBE()))
		t.Run("TooMuchArguments", runInvalid(
			stackitem.NewArray([]stackitem.Item{
				stackitem.Make(1), stackitem.Make(2), stackitem.Make(3), stackitem.Make(4)}),
			"add", h.BytesBE()))
	})

	t.Run("ReturnValues", func(t *testing.T) {
		t.Run("Many", func(t *testing.T) {
			loadScript(ic, currScript, 42)
			ic.VM.Estack().PushVal(stackitem.NewArray(nil))
			ic.VM.Estack().PushVal(callflag.All)
			ic.VM.Estack().PushVal("invalidReturn")
			ic.VM.Estack().PushVal(h.BytesBE())
			require.NoError(t, contract.Call(ic))
			require.Error(t, ic.VM.Run())
		})
		t.Run("Void", func(t *testing.T) {
			loadScript(ic, currScript, 42)
			ic.VM.Estack().PushVal(stackitem.NewArray(nil))
			ic.VM.Estack().PushVal(callflag.All)
			ic.VM.Estack().PushVal("justReturn")
			ic.VM.Estack().PushVal(h.BytesBE())
			require.NoError(t, contract.Call(ic))
			require.NoError(t, ic.VM.Run())
			require.Equal(t, 2, ic.VM.Estack().Len())
			require.Equal(t, stackitem.Null{}, ic.VM.Estack().Pop().Item())
			require.Equal(t, big.NewInt(42), ic.VM.Estack().Pop().Value())
		})
	})

	t.Run("IsolatedStack", func(t *testing.T) {
		loadScript(ic, currScript, 42)
		ic.VM.Estack().PushVal(stackitem.NewArray(nil))
		ic.VM.Estack().PushVal(callflag.All)
		ic.VM.Estack().PushVal("drop")
		ic.VM.Estack().PushVal(h.BytesBE())
		require.NoError(t, contract.Call(ic))
		require.Error(t, ic.VM.Run())
	})

	t.Run("CallInitialize", func(t *testing.T) {
		t.Run("Directly", runInvalid(stackitem.NewArray([]stackitem.Item{}), "_initialize", h.BytesBE()))

		loadScript(ic, currScript, 42)
		ic.VM.Estack().PushVal(stackitem.NewArray([]stackitem.Item{stackitem.Make(5)}))
		ic.VM.Estack().PushVal(callflag.All)
		ic.VM.Estack().PushVal("add3")
		ic.VM.Estack().PushVal(h.BytesBE())
		require.NoError(t, contract.Call(ic))
		require.NoError(t, ic.VM.Run())
		require.Equal(t, 2, ic.VM.Estack().Len())
		require.Equal(t, big.NewInt(8), ic.VM.Estack().Pop().Value())
		require.Equal(t, big.NewInt(42), ic.VM.Estack().Pop().Value())
	})
}

func loadScript(ic *interop.Context, script []byte, args ...interface{}) {
	ic.SpawnVM()
	ic.VM.LoadScriptWithFlags(script, callflag.AllowCall)
	for i := range args {
		ic.VM.Estack().PushVal(args[i])
	}
	ic.VM.GasLimit = -1
}

func loadScriptWithHashAndFlags(ic *interop.Context, script []byte, hash util.Uint160, f callflag.CallFlag, args ...interface{}) {
	ic.SpawnVM()
	ic.VM.LoadScriptWithHash(script, hash, f)
	for i := range args {
		ic.VM.Estack().PushVal(args[i])
	}
	ic.VM.GasLimit = -1
}