# Stint
# Copyright 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 ../stint, unittest, test_helpers

template chkMul(chk: untyped, a, b, c: string, bits: int) =
  chk (fromHex(Stint[bits], a) * fromHex(Stint[bits], b)) == fromHex(Stint[bits], c)

template chkDiv(chk: untyped, a, b, c: string, bits: int) =
  chk (fromHex(Stint[bits], a) div fromHex(Stint[bits], b)) == fromHex(Stint[bits], c)

template chkMod(chk: untyped, a, b, c: string, bits: int) =
  chk (fromHex(Stint[bits], a) mod fromHex(Stint[bits], b)) == fromHex(Stint[bits], c)

template chkDivMod(chk: untyped, a, b, c, d: string, bits: int) =
  chk divmod(fromHex(Stint[bits], a), fromHex(Stint[bits], b)) == (fromHex(Stint[bits], c), fromHex(Stint[bits], d))

template testMuldiv(chk, tst: untyped) =
  tst "operator `mul`":
    chkMul(chk, "0", "3", "0", 8)
    chkMul(chk, "1", "3", "3", 8)
    chkMul(chk, "F0", "3", "D0", 8)
    chkMul(chk, "FF", "FF", "1", 8)

    chkMul(chk, "0", "3", "0", 16)
    chkMul(chk, "1", "3", "3", 16)
    chkMul(chk, "F0", "3", "2D0", 16)
    chkMul(chk, "F000", "3", "D000", 16)
    chkMul(chk, "FFFF", "FFFF", "1", 16)

    chkMul(chk, "0", "3", "0", 32)
    chkMul(chk, "1", "3", "3", 32)
    chkMul(chk, "F0", "3", "2D0", 32)
    chkMul(chk, "F000", "3", "2D000", 32)
    chkMul(chk, "F0000000", "3", "D0000000", 32)
    chkMul(chk, "FFFFFFFF", "FFFFFFFF", "1", 32)

    chkMul(chk, "0", "3", "0", 64)
    chkMul(chk, "1", "3", "3", 64)
    chkMul(chk, "F0", "3", "2D0", 64)
    chkMul(chk, "F000", "3", "2D000", 64)
    chkMul(chk, "F0000000", "3", "2D0000000", 64)
    chkMul(chk, "F000000000000000", "3", "D000000000000000", 64)
    chkMul(chk, "FFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFF", "1", 64)

    chkMul(chk, "0", "3", "0", 128)
    chkMul(chk, "1", "3", "3", 128)
    chkMul(chk, "F0", "3", "2D0", 128)
    chkMul(chk, "F000", "3", "2D000", 128)
    chkMul(chk, "F0000000", "3", "2D0000000", 128)
    chkMul(chk, "F000000000000000", "3", "2D000000000000000", 128)
    chkMul(chk, "F0000000000000000000000000000000", "3", "D0000000000000000000000000000000", 128)
    chkMul(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "1", 128)

  tst "operator `div`":
    chkDiv(chk, "0", "3", "0", 8)
    chkDiv(chk, "1", "3", "0", 8)
    chkDiv(chk, "3", "3", "1", 8)
    chkDiv(chk, "3", "1", "3", 8)
    chkDiv(chk, "FF", "3", "0", 8)
    chkDiv(chk, "0F", "FF", "F1", 8)
    chkDiv(chk, "FF", "FF", "1", 8)

    chkDiv(chk, "0", "3", "0", 16)
    chkDiv(chk, "1", "3", "0", 16)
    chkDiv(chk, "3", "3", "1", 16)
    chkDiv(chk, "3", "1", "3", 16)
    chkDiv(chk, "FF", "3", "55", 16)
    chkDiv(chk, "0F", "FF", "0", 16)
    chkDiv(chk, "FF", "FF", "1", 16)
    chkDiv(chk, "FFFF", "3", "0", 16)
    chkDiv(chk, "0F", "FFFF", "FFF1", 16)
    chkDiv(chk, "FFFF", "FFFF", "1", 16)


    chkDiv(chk, "0", "3", "0", 32)
    chkDiv(chk, "1", "3", "0", 32)
    chkDiv(chk, "3", "3", "1", 32)
    chkDiv(chk, "3", "1", "3", 32)
    chkDiv(chk, "FF", "3", "55", 32)
    chkDiv(chk, "0F", "FF", "0", 32)
    chkDiv(chk, "FF", "FF", "1", 32)
    chkDiv(chk, "FFFF", "3", "5555", 32)
    chkDiv(chk, "0F", "FFFFFFFF", "FFFFFFF1", 32)
    chkDiv(chk, "FFFFFFFF", "FFFFFFFF", "1", 32)

    chkDiv(chk, "0", "3", "0", 64)
    chkDiv(chk, "1", "3", "0", 64)
    chkDiv(chk, "3", "3", "1", 64)
    chkDiv(chk, "3", "1", "3", 64)
    chkDiv(chk, "FF", "3", "55", 64)
    chkDiv(chk, "0F", "FF", "0", 64)
    chkDiv(chk, "FF", "FF", "1", 64)
    chkDiv(chk, "FFFF", "3", "5555", 64)
    chkDiv(chk, "0F", "FFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFF1", 64)
    chkDiv(chk, "FFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFFF", "1", 64)

    chkDiv(chk, "0", "3", "0", 128)
    chkDiv(chk, "1", "3", "0", 128)
    chkDiv(chk, "3", "3", "1", 128)
    chkDiv(chk, "3", "1", "3", 128)
    chkDiv(chk, "FF", "3", "55", 128)
    chkDiv(chk, "0F", "FF", "0", 128)
    chkDiv(chk, "FF", "FF", "1", 128)
    chkDiv(chk, "FFFF", "3", "5555", 128)
    chkDiv(chk, "0F", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF1", 128)
    chkDiv(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "1", 128)

  tst "operator `mod`":
    chkMod(chk, "0", "3", "0", 8)
    chkMod(chk, "1", "3", "1", 8)
    chkMod(chk, "3", "3", "0", 8)
    chkMod(chk, "3", "1", "0", 8)
    chkMod(chk, "FF", "3", "FF", 8)
    chkMod(chk, "FF", "4", "FF", 8)
    chkMod(chk, "FF", "FF", "0", 8)
    chkMod(chk, "0F", "FC", "3", 8)

    chkMod(chk, "0", "3", "0", 16)
    chkMod(chk, "1", "3", "1", 16)
    chkMod(chk, "3", "3", "0", 16)
    chkMod(chk, "3", "1", "0", 16)
    chkMod(chk, "FFFF", "3", "FFFF", 16)
    chkMod(chk, "FFFF", "4", "FFFF", 16)
    chkMod(chk, "FFFF", "FFFF", "0", 16)
    chkMod(chk, "0F", "FFFC", "3", 16)

    chkMod(chk, "0", "3", "0", 32)
    chkMod(chk, "1", "3", "1", 32)
    chkMod(chk, "3", "3", "0", 32)
    chkMod(chk, "3", "1", "0", 32)
    chkMod(chk, "FFFFFFFF", "3", "FFFFFFFF", 32)
    chkMod(chk, "FFFFFFFF", "4", "FFFFFFFF", 32)
    chkMod(chk, "FFFFFFFF", "FFFFFFFF", "0", 32)
    chkMod(chk, "0F", "FFFFFFFC", "3", 32)

    chkMod(chk, "0", "3", "0", 64)
    chkMod(chk, "1", "3", "1", 64)
    chkMod(chk, "3", "3", "0", 64)
    chkMod(chk, "3", "1", "0", 64)
    chkMod(chk, "FFFFFFFFFFFFFFFF", "3", "FFFFFFFFFFFFFFFF", 64)
    chkMod(chk, "FFFFFFFFFFFFFFFF", "4", "FFFFFFFFFFFFFFFF", 64)
    chkMod(chk, "FFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFF", "0", 64)
    chkMod(chk, "0F", "FFFFFFFFFFFFFFFC", "3", 64)

    chkMod(chk, "0", "3", "0", 128)
    chkMod(chk, "1", "3", "1", 128)
    chkMod(chk, "3", "3", "0", 128)
    chkMod(chk, "3", "1", "0", 128)
    chkMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "3", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 128)
    chkMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "4", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 128)
    chkMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "0", 128)
    chkMod(chk, "0F", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC", "3", 128)

  tst "operator `divmod`":
    chkDivMod(chk, "0", "3", "0", "0", 8)
    chkDivMod(chk, "1", "3", "0", "1", 8)
    chkDivMod(chk, "3", "3", "1", "0", 8)
    chkDivMod(chk, "3", "1", "3", "0", 8)
    chkDivMod(chk, "FF", "3", "0", "FF", 8)
    chkDivMod(chk, "FF", "4", "0", "FF", 8)
    chkDivMod(chk, "FF", "FF", "1", "0", 8)
    chkDivMod(chk, "0F", "FC", "FD", "3", 8)

    chkDivMod(chk, "0", "3", "0", "0", 16)
    chkDivMod(chk, "1", "3", "0", "1", 16)
    chkDivMod(chk, "3", "3", "1", "0", 16)
    chkDivMod(chk, "3", "1", "3", "0", 16)
    chkDivMod(chk, "FFFF", "3", "0", "FFFF", 16)
    chkDivMod(chk, "FFFF", "4", "0", "FFFF", 16)
    chkDivMod(chk, "FFFF", "FFFF", "1", "0", 16)
    chkDivMod(chk, "0F", "FFFC", "FFFD", "3", 16)

    chkDivMod(chk, "0", "3", "0", "0", 32)
    chkDivMod(chk, "1", "3", "0", "1", 32)
    chkDivMod(chk, "3", "3", "1", "0", 32)
    chkDivMod(chk, "3", "1", "3", "0", 32)
    chkDivMod(chk, "FFFFFFFF", "3", "0", "FFFFFFFF", 32)
    chkDivMod(chk, "FFFFFFFF", "4", "0", "FFFFFFFF", 32)
    chkDivMod(chk, "FFFFFFFF", "FFFFFFFF", "1", "0", 32)
    chkDivMod(chk, "0F", "FFFFFFFC", "FFFFFFFD", "3", 32)

    chkDivMod(chk, "0", "3", "0", "0", 64)
    chkDivMod(chk, "1", "3", "0", "1", 64)
    chkDivMod(chk, "3", "3", "1", "0", 64)
    chkDivMod(chk, "3", "1", "3", "0", 64)
    chkDivMod(chk, "FFFFFFFFFFFFFFFF", "3", "0", "FFFFFFFFFFFFFFFF", 64)
    chkDivMod(chk, "FFFFFFFFFFFFFFFF", "4", "0", "FFFFFFFFFFFFFFFF", 64)
    chkDivMod(chk, "FFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFF", "1", "0", 64)
    chkDivMod(chk, "0F", "FFFFFFFFFFFFFFFC", "FFFFFFFFFFFFFFFD", "3", 64)

    chkDivMod(chk, "0", "3", "0", "0", 128)
    chkDivMod(chk, "1", "3", "0", "1", 128)
    chkDivMod(chk, "3", "3", "1", "0", 128)
    chkDivMod(chk, "3", "1", "3", "0", 128)
    chkDivMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "3", "0", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 128)
    chkDivMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "4", "0", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", 128)
    chkDivMod(chk, "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF", "1", "0", 128)
    chkDivMod(chk, "0F", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFC", "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFD", "3", 128)

static:
  testMuldiv(ctCheck, ctTest)

suite "Wider signed int muldiv coverage":
  testMuldiv(check, test)

suite "Testing signed int multiplication implementation":
  test "Multiplication with result fitting in low half":

    let a = 10000.stint(64)
    let b = 10000.stint(64)

    check: cast[int64](a*b) == 100_000_000'i64 # need 27-bits

  test "Multiplication with result overflowing low half":

    let a = 1_000_000.stint(64)
    let b = 1_000_000.stint(64)

    check: cast[int64](a*b) == 1_000_000_000_000'i64 # need 40 bits

  test "Multiplication with result fitting in low half - opposite signs":

    let a = -10000.stint(64)
    let b = 10000.stint(64)

    check:
      cast[int64](a*b) == -100_000_000'i64 # need 27-bits
      cast[int64](b*a) == -100_000_000'i64


  test "Multiplication with result overflowing low half - opposite signs":

    let a = -1_000_000.stint(64)
    let b = 1_000_000.stint(64)

    check:
      cast[int64](a*b) == -1_000_000_000_000'i64 # need 40 bits
      cast[int64](b*a) == -1_000_000_000_000'i64

  test "Multiplication with result fitting in low half - both negative":

    let a = -10000.stint(64)
    let b = -10000.stint(64)

    check: cast[int64](a*b) == 100_000_000'i64 # need 27-bits

  test "Multiplication with result overflowing low half - both negative":

    let a = -1_000_000.stint(64)
    let b = -1_000_000.stint(64)

    check: cast[int64](a*b) == 1_000_000_000_000'i64 # need 40 bits

suite "Testing signed int division and modulo implementation":
  test "Divmod(100, 13) returns the correct result":

    let a = 100.stint(64)
    let b = 13.stint(64)
    let qr = divmod(a, b)

    check: cast[int64](qr.quot) == 7'i64
    check: cast[int64](qr.rem)  == 9'i64

  test "Divmod(-100, 13) returns the correct result":

    let a = -100.stint(64)
    let b = 13.stint(64)
    let qr = divmod(a, b)

    check: cast[int64](qr.quot) == -100'i64 div 13
    check: cast[int64](qr.rem)  == -100'i64 mod 13

  test "Divmod(100, -13) returns the correct result":

    let a = 100.stint(64)
    let b = -13.stint(64)
    let qr = divmod(a, b)

    check: cast[int64](qr.quot) == 100'i64 div -13
    check: cast[int64](qr.rem)  == 100'i64 mod -13

  test "Divmod(-100, -13) returns the correct result":

    let a = -100.stint(64)
    let b = -13.stint(64)
    let qr = divmod(a, b)

    check: cast[int64](qr.quot) == -100'i64 div -13
    check: cast[int64](qr.rem)  == -100'i64 mod -13

  # test "Divmod(2^64, 3) returns the correct result":
  #   let a = 1.stint(128) shl 64
  #   let b = 3.stint(128)

  #   let qr = divmod(a, b)

  #   let q = cast[UintImpl[uint64]](qr.quot)
  #   let r = cast[UintImpl[uint64]](qr.rem)

  #   check: q.lo == 6148914691236517205'u64
  #   check: q.hi == 0'u64
  #   check: r.lo == 1'u64
  #   check: r.hi == 0'u64

  test "Divmod(1234567891234567890, 10) returns the correct result":
    let a = cast[Stint[64]](1234567891234567890'i64)
    let b = cast[Stint[64]](10'i64)

    let qr = divmod(a, b)

    let q = cast[int64](qr.quot)
    let r = cast[int64](qr.rem)

    check: q == 123456789123456789'i64
    check: r == 0'i64