# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except according to those terms.

import
  unittest,
  eth_common/eth_types,
  ../nimbus/[constants, errors, vm/interpreter]


template testPush(value: untyped, expected: untyped): untyped =
  var stack = newStack()
  stack.push(value)
  check(stack.values == @[expected])

template testFailPush(value: untyped): untyped =
  var stack = newStack()
  expect(ValidationError):
    stack.push(value)

func toBytes(s: string): seq[byte] =
  cast[seq[byte]](s)

func bigEndianToInt*(value: openarray[byte]): UInt256 =
  result.initFromBytesBE(value)

suite "stack":
  test "push only valid":
    testPush(0'u, 0.u256)
    testPush(UINT_256_MAX, UINT_256_MAX)
    testPush("ves".toBytes, "ves".toBytes.bigEndianToInt)

    testFailPush("yzyzyzyzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz".toBytes)

  test "push does not allow stack to exceed 1024":
    var stack = newStack()
    for z in 0 .. < 1024:
      stack.push(z.uint)
    check(stack.len == 1024)
    expect(FullStack):
      stack.push(1025)

  test "dup does not allow stack to exceed 1024":
    var stack = newStack()
    stack.push(1.u256)
    for z in 0 ..< 1023:
      stack.dup(1)
    check(stack.len == 1024)
    expect(FullStack):
      stack.dup(1)

  test "pop returns latest stack item":
    var stack = newStack()
    for element in @[1'u, 2'u, 3'u]:
      stack.push(element)
    check(stack.popInt == 3.u256)

  test "swap correct":
    var stack = newStack()
    for z in 0 ..< 5:
      stack.push(z.uint)
    check(stack.values == @[0.u256, 1.u256, 2.u256, 3.u256, 4.u256])
    stack.swap(3)
    check(stack.values == @[0.u256, 4.u256, 2.u256, 3.u256, 1.u256])
    stack.swap(1)
    check(stack.values == @[0.u256, 4.u256, 2.u256, 1.u256, 3.u256])

  test "dup correct":
    var stack = newStack()
    for z in 0 ..< 5:
      stack.push(z.uint)
    check(stack.values == @[0.u256, 1.u256, 2.u256, 3.u256, 4.u256])
    stack.dup(1)
    check(stack.values == @[0.u256, 1.u256, 2.u256, 3.u256, 4.u256, 4.u256])
    stack.dup(5)
    check(stack.values == @[0.u256, 1.u256, 2.u256, 3.u256, 4.u256, 4.u256, 1.u256])

  test "pop raises InsufficientStack appropriately":
    var stack = newStack()
    expect(InsufficientStack):
      discard stack.popInt()

  test "swap raises InsufficientStack appropriately":
    var stack = newStack()
    expect(InsufficientStack):
      stack.swap(0)

  test "dup raises InsufficientStack appropriately":
    var stack = newStack()
    expect(InsufficientStack):
      stack.dup(0)

  test "binary operations raises InsufficientStack appropriately":
    # https://github.com/status-im/nimbus/issues/31
    # ./tests/fixtures/VMTests/vmArithmeticTest/mulUnderFlow.json

    var stack = newStack()
    stack.push(123)
    expect(InsufficientStack):
      discard stack.popInt(2)