# frozen_string_literal: false

require 'tempfile'

class TestIOBuffer < Test::Unit::TestCase
  experimental = Warning[:experimental]
  begin
    Warning[:experimental] = false
    IO::Buffer.new(0)
  ensure
    Warning[:experimental] = experimental
  end

  def assert_negative(value)
    assert(value < 0, "Expected #{value} to be negative!")
  end

  def assert_positive(value)
    assert(value > 0, "Expected #{value} to be positive!")
  end

  def test_flags
    assert_equal 1, IO::Buffer::EXTERNAL
    assert_equal 2, IO::Buffer::INTERNAL
    assert_equal 4, IO::Buffer::MAPPED

    assert_equal 32, IO::Buffer::LOCKED
    assert_equal 64, IO::Buffer::PRIVATE

    assert_equal 128, IO::Buffer::READONLY
  end

  def test_endian
    assert_equal 4, IO::Buffer::LITTLE_ENDIAN
    assert_equal 8, IO::Buffer::BIG_ENDIAN
    assert_equal 8, IO::Buffer::NETWORK_ENDIAN

    assert_include [IO::Buffer::LITTLE_ENDIAN, IO::Buffer::BIG_ENDIAN], IO::Buffer::HOST_ENDIAN
  end

  def test_default_size
    assert_equal IO::Buffer::DEFAULT_SIZE, IO::Buffer.new.size
  end

  def test_new_internal
    buffer = IO::Buffer.new(1024, IO::Buffer::INTERNAL)
    assert_equal 1024, buffer.size
    refute buffer.external?
    assert buffer.internal?
    refute buffer.mapped?
  end

  def test_new_mapped
    buffer = IO::Buffer.new(1024, IO::Buffer::MAPPED)
    assert_equal 1024, buffer.size
    refute buffer.external?
    refute buffer.internal?
    assert buffer.mapped?
  end

  def test_new_readonly
    buffer = IO::Buffer.new(128, IO::Buffer::INTERNAL|IO::Buffer::READONLY)
    assert buffer.readonly?

    assert_raise IO::Buffer::AccessError do
      buffer.set_string("")
    end

    assert_raise IO::Buffer::AccessError do
      buffer.set_string("!", 1)
    end
  end

  def test_file_mapped
    buffer = File.open(__FILE__) {|file| IO::Buffer.map(file, nil, 0, IO::Buffer::READONLY)}
    contents = buffer.get_string

    assert_include contents, "Hello World"
    assert_equal Encoding::BINARY, contents.encoding
  end

  def test_file_mapped_invalid
    assert_raise NoMethodError do
      IO::Buffer.map("foobar")
    end
  end

  def test_string_mapped
    string = "Hello World"
    buffer = IO::Buffer.for(string)
    assert buffer.readonly?
  end

  def test_string_mapped_frozen
    string = "Hello World".freeze
    buffer = IO::Buffer.for(string)
    assert buffer.readonly?
  end

  def test_string_mapped_mutable
    string = "Hello World"
    IO::Buffer.for(string) do |buffer|
      refute buffer.readonly?

      # Cannot modify string as it's locked by the buffer:
      assert_raise RuntimeError do
        string[0] = "h"
      end

      buffer.set_value(:U8, 0, "h".ord)

      # Buffer releases it's ownership of the string:
      buffer.free

      assert_equal "hello World", string
    end
  end

  def test_non_string
    not_string = Object.new

    assert_raise TypeError do
      IO::Buffer.for(not_string)
    end
  end

  def test_resize_mapped
    buffer = IO::Buffer.new

    buffer.resize(2048)
    assert_equal 2048, buffer.size

    buffer.resize(4096)
    assert_equal 4096, buffer.size
  end

  def test_resize_preserve
    message = "Hello World"
    buffer = IO::Buffer.new(1024)
    buffer.set_string(message)
    buffer.resize(2048)
    assert_equal message, buffer.get_string(0, message.bytesize)
  end

  def test_compare_same_size
    buffer1 = IO::Buffer.new(1)
    assert_equal buffer1, buffer1

    buffer2 = IO::Buffer.new(1)
    buffer1.set_value(:U8, 0, 0x10)
    buffer2.set_value(:U8, 0, 0x20)

    assert_negative buffer1 <=> buffer2
    assert_positive buffer2 <=> buffer1
  end

  def test_compare_different_size
    buffer1 = IO::Buffer.new(3)
    buffer2 = IO::Buffer.new(5)

    assert_negative buffer1 <=> buffer2
    assert_positive buffer2 <=> buffer1
  end

  def test_slice
    buffer = IO::Buffer.new(128)
    slice = buffer.slice(8, 32)
    slice.set_string("Hello World")
    assert_equal("Hello World", buffer.get_string(8, 11))
  end

  def test_slice_arguments
    buffer = IO::Buffer.for("Hello World")

    slice = buffer.slice
    assert_equal "Hello World", slice.get_string

    slice = buffer.slice(2)
    assert_equal("llo World", slice.get_string)
  end

  def test_slice_bounds_error
    buffer = IO::Buffer.new(128)

    assert_raise ArgumentError do
      buffer.slice(128, 10)
    end

    assert_raise ArgumentError do
      buffer.slice(-10, 10)
    end
  end

  def test_locked
    buffer = IO::Buffer.new(128, IO::Buffer::INTERNAL|IO::Buffer::LOCKED)

    assert_raise IO::Buffer::LockedError do
      buffer.resize(256)
    end

    assert_equal 128, buffer.size

    assert_raise IO::Buffer::LockedError do
      buffer.free
    end

    assert_equal 128, buffer.size
  end

  def test_get_string
    message = "Hello World 🤓"

    buffer = IO::Buffer.new(128)
    buffer.set_string(message)

    chunk = buffer.get_string(0, message.bytesize, Encoding::UTF_8)
    assert_equal message, chunk
    assert_equal Encoding::UTF_8, chunk.encoding

    chunk = buffer.get_string(0, message.bytesize, Encoding::BINARY)
    assert_equal Encoding::BINARY, chunk.encoding
  end

  # We check that values are correctly round tripped.
  RANGES = {
    :U8 => [0, 2**8-1],
    :S8 => [-2**7, 0, 2**7-1],

    :U16 => [0, 2**16-1],
    :S16 => [-2**15, 0, 2**15-1],
    :u16 => [0, 2**16-1],
    :s16 => [-2**15, 0, 2**15-1],

    :U32 => [0, 2**32-1],
    :S32 => [-2**31, 0, 2**31-1],
    :u32 => [0, 2**32-1],
    :s32 => [-2**31, 0, 2**31-1],

    :U64 => [0, 2**64-1],
    :S64 => [-2**63, 0, 2**63-1],
    :u64 => [0, 2**64-1],
    :s64 => [-2**63, 0, 2**63-1],

    :F32 => [-1.0, 0.0, 0.5, 1.0, 128.0],
    :F64 => [-1.0, 0.0, 0.5, 1.0, 128.0],
  }

  def test_get_set_value
    buffer = IO::Buffer.new(128)

    RANGES.each do |data_type, values|
      values.each do |value|
        buffer.set_value(data_type, 0, value)
        assert_equal value, buffer.get_value(data_type, 0), "Converting #{value} as #{data_type}."
      end
    end
  end

  def test_get_set_values
    buffer = IO::Buffer.new(128)

    RANGES.each do |data_type, values|
      format = [data_type] * values.size

      buffer.set_values(format, 0, values)
      assert_equal values, buffer.get_values(format, 0), "Converting #{values} as #{format}."
    end
  end

  def test_values
    buffer = IO::Buffer.new(128)

    RANGES.each do |data_type, values|
      format = [data_type] * values.size

      buffer.set_values(format, 0, values)
      assert_equal values, buffer.values(data_type, 0, values.size), "Reading #{values} as #{format}."
    end
  end

  def test_each
    buffer = IO::Buffer.new(128)

    RANGES.each do |data_type, values|
      format = [data_type] * values.size
      data_type_size = IO::Buffer.size_of(data_type)
      values_with_offsets = values.map.with_index{|value, index| [index * data_type_size, value]}

      buffer.set_values(format, 0, values)
      assert_equal values_with_offsets, buffer.each(data_type, 0, values.size).to_a, "Reading #{values} as #{data_type}."
    end
  end

  def test_each_byte
    string = "The quick brown fox jumped over the lazy dog."
    buffer = IO::Buffer.for(string)

    assert_equal string.bytes, buffer.each_byte.to_a
  end

  def test_clear
    buffer = IO::Buffer.new(16)
    buffer.set_string("Hello World!")
  end

  def test_invalidation
    input, output = IO.pipe

    # (1) rb_write_internal creates IO::Buffer object,
    buffer = IO::Buffer.new(128)

    # (2) it is passed to (malicious) scheduler
    # (3) scheduler starts a thread which call system call with the buffer object
    thread = Thread.new{buffer.locked{input.read}}

    Thread.pass until thread.stop?

    # (4) scheduler returns
    # (5) rb_write_internal invalidate the buffer object
    assert_raise IO::Buffer::LockedError do
      buffer.free
    end

    # (6) the system call access the memory area after invalidation
    output.write("Hello World")
    output.close
    thread.join

    input.close
  end

  def test_read
    io = Tempfile.new
    io.write("Hello World")
    io.seek(0)

    buffer = IO::Buffer.new(128)
    buffer.read(io, 5)

    assert_equal "Hello", buffer.get_string(0, 5)
  ensure
    io.close!
  end

  def test_write
    io = Tempfile.new

    buffer = IO::Buffer.new(128)
    buffer.set_string("Hello")
    buffer.write(io, 5)

    io.seek(0)
    assert_equal "Hello", io.read(5)
  ensure
    io.close!
  end

  def test_pread
    io = Tempfile.new
    io.write("Hello World")
    io.seek(0)

    buffer = IO::Buffer.new(128)
    buffer.pread(io, 6, 5)

    assert_equal "World", buffer.get_string(0, 5)
    assert_equal 0, io.tell
  ensure
    io.close!
  end

  def test_pwrite
    io = Tempfile.new

    buffer = IO::Buffer.new(128)
    buffer.set_string("World")
    buffer.pwrite(io, 6, 5)

    assert_equal 0, io.tell

    io.seek(6)
    assert_equal "World", io.read(5)
  ensure
    io.close!
  end

  def test_operators
    source = IO::Buffer.for("1234123412")
    mask = IO::Buffer.for("133\x00")

    assert_equal IO::Buffer.for("123\x00123\x0012"), (source & mask)
    assert_equal IO::Buffer.for("1334133413"), (source | mask)
    assert_equal IO::Buffer.for("\x00\x01\x004\x00\x01\x004\x00\x01"), (source ^ mask)
    assert_equal IO::Buffer.for("\xce\xcd\xcc\xcb\xce\xcd\xcc\xcb\xce\xcd"), ~source
  end

  def test_inplace_operators
    source = IO::Buffer.for("1234123412")
    mask = IO::Buffer.for("133\x00")

    assert_equal IO::Buffer.for("123\x00123\x0012"), source.dup.and!(mask)
    assert_equal IO::Buffer.for("1334133413"), source.dup.or!(mask)
    assert_equal IO::Buffer.for("\x00\x01\x004\x00\x01\x004\x00\x01"), source.dup.xor!(mask)
    assert_equal IO::Buffer.for("\xce\xcd\xcc\xcb\xce\xcd\xcc\xcb\xce\xcd"), source.dup.not!
  end

  def test_shared
    message = "Hello World"
    buffer = IO::Buffer.new(64, IO::Buffer::MAPPED | IO::Buffer::SHARED)

    pid = fork do
      buffer.set_string(message)
    end

    Process.wait(pid)
    string = buffer.get_string(0, message.bytesize)
    assert_equal message, string
  rescue NotImplementedError
    omit "Fork/shared memory is not supported."
  end
end