# gzip-like LZSS compressor
# Copyright (C) 2018  Pacien TRAN-GIRARD
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.

import unittest, sequtils, lists, tables
import matchtable, lzssnode, lzsschain, lzssencoder

suite "lzssencoder":
  test "commonPrefixLength":
    check commonPrefixLength([], [], 0, 10) == 0
    check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 0, 10) == 2
    check commonPrefixLength([1'u8, 2], [1'u8, 2, 3], 1, 10) == 2
    check commonPrefixLength([1'u8, 2, 3], [1'u8, 2, 4], 1, 10) == 2
    check commonPrefixLength([1'u8, 2, 3, 4], [1'u8, 2, 3, 4], 1, 3) == 3

  test "longestPrefix":
    let buffer = [
      0'u8, 1, 2, 9,
      0, 1, 2, 3,
      0, 1, 2,
      0, 1, 2, 3, 4]
    var candidatePos = initSinglyLinkedList[int]()
    candidatePos.prepend(0)
    candidatePos.prepend(4)
    candidatePos.prepend(8)
    let result = longestPrefix(candidatePos, buffer.toOpenArray(0, 10), buffer.toOpenArray(11, buffer.len - 1))
    check result.pos == 4
    check result.length == 4

  test "addGroups":
    let matchTable = initMatchTable(seq[uint8], int)
    let buffer = toSeq(0'u8..10'u8)
    matchTable.addGroups(buffer, 0, 1)
    check matchTable.len == 0
    matchTable.addGroups(buffer, 2, 9)
    check matchTable.len == 5
    check toSeq(matchTable.matchList(@[1'u8, 2, 3]).items).len == 0
    check toSeq(matchTable.matchList(@[7'u8, 8, 9]).items).len == 0
    check toSeq(matchTable.matchList(@[2'u8, 3, 4]).items) == @[2]
    check toSeq(matchTable.matchList(@[4'u8, 5, 6]).items) == @[4]
    check toSeq(matchTable.matchList(@[6'u8, 7, 8]).items) == @[6]

  test "lzssEncode":
    let buffer = [0'u8, 1, 2, 3, 4, 5, 0, 1, 2, 3, 0, 1, 4, 5, 0, 5, 5, 0, 5, 5]
    check toSeq(lzssEncode(buffer).items) == @[
      lzssCharacter(0), lzssCharacter(1), lzssCharacter(2),
      lzssCharacter(3), lzssCharacter(4), lzssCharacter(5),
      lzssReference(4, 6), lzssCharacter(0), lzssCharacter(1),
      lzssReference(3, 8), lzssCharacter(5),
      lzssReference(3, 3), lzssCharacter(5)]