# rubocop:todo all
require 'spec_helper'

describe BSON::ByteBuffer do

  let(:buffer) do
    described_class.new
  end

  shared_examples_for 'does not write' do
    it 'raises ArgumentError' do
      expect do
        modified
      end.to raise_error(ArgumentError)
    end

    it 'does not change write position' do
      expect do
        modified
      end.to raise_error(ArgumentError)

      expect(buffer.write_position).to eq(0)
    end
  end

  describe '#put_byte' do

    let(:modified) do
      buffer.put_byte(BSON::Int32::BSON_TYPE)
    end

    it 'appends the byte to the byte buffer' do
      expect(modified.to_s).to eq(BSON::Int32::BSON_TYPE.chr)
    end

    it 'increments the write position by 1' do
      expect(modified.write_position).to eq(1)
    end

    context 'when it receives a numeric value' do
      it 'raises the ArgumentError exception' do
        expect{buffer.put_byte(1)}.to raise_error(ArgumentError)
      end
    end

    context 'when it receives a nil value' do
      it 'raises the ArgumentError exception' do
        expect{buffer.put_byte(nil)}.to raise_error(ArgumentError)
      end
    end

    context 'when given a string of length > 1' do

      let(:modified) do
        buffer.put_byte('xx')
      end

      it_behaves_like 'does not write'
    end

    context 'when given a string of length 0' do

      let(:modified) do
        buffer.put_byte('')
      end

      it_behaves_like 'does not write'
    end

    context 'when byte is not valid utf-8' do
      let(:string) do
        Utils.make_byte_string([254]).freeze
      end

      let(:modified) do
        buffer.put_byte(string)
      end

      it 'writes the byte' do
        expect(modified.to_s).to eq(string)
      end
    end
  end

  describe '#put_bytes' do

    let(:modified) do
      buffer.put_bytes(BSON::Int32::BSON_TYPE)
      buffer
    end

    it 'increments the write position by 1' do
      expect(modified.write_position).to eq(1)
    end

    context 'when it receives a numeric value' do
      it 'raises the ArgumentError exception' do
        expect{buffer.put_bytes(1)}.to raise_error(ArgumentError)
      end
    end

    context 'when it receives a nil value' do
      it 'raises the ArgumentError exception' do
        expect{buffer.put_bytes(nil)}.to raise_error(ArgumentError)
      end
    end

    context 'when given a string with null bytes' do
      let(:byte_str) { [0, 239, 254, 0].map(&:chr).join }

      let(:modified) do
        buffer.put_bytes(byte_str)
      end

      before do
        expect(buffer.write_position).to eq(0)
        expect(byte_str.length).to eq(4)
      end

      it 'writes the string' do
        expect(modified.write_position).to eq(4)
      end
    end

    context 'when bytes are not valid utf-8' do
      let(:string) do
        Utils.make_byte_string([254, 0, 255]).freeze
      end

      let(:modified) do
        buffer.put_bytes(string)
      end

      it 'writes the bytes' do
        expect(modified.to_s).to eq(string)
      end
    end
  end

  shared_examples_for 'bson string writer' do

    context 'given empty string' do
      let(:modified) do
        buffer.put_string('')
      end

      it 'writes length and null terminator' do
        expect(modified.write_position).to eq(5)
      end
    end

    context 'when string is not valid utf-8 in utf-8 encoding' do
      let(:string) do
        Utils.make_byte_string([254, 253, 255], 'utf-8')
      end

      before do
        expect(string.encoding.name).to eq('UTF-8')
      end

      it 'raises EncodingError' do
        # Precise exception classes and messages differ between MRI and JRuby
        expect do
          modified
        end.to raise_error(EncodingError)
      end
    end

    context 'when string is in binary encoding and cannot be encoded in utf-8' do
      let(:string) do
        Utils.make_byte_string([254, 253, 255], 'binary')
      end

      before do
        expect(string.encoding.name).to eq('ASCII-8BIT')
      end

      it 'raises Encoding::UndefinedConversionError' do
        expect do
          modified
        end.to raise_error(Encoding::UndefinedConversionError, /from ASCII-8BIT to UTF-8/)
      end
    end
  end

  describe '#put_string' do

    let(:modified) do
      buffer.put_string(string)
    end

    it_behaves_like 'bson string writer'

    context 'when the buffer does not need to be expanded' do

      context 'when the string is UTF-8' do

        let!(:modified) do
          buffer.put_string('testing')
        end

        it 'appends the string to the byte buffer' do
          expect(modified.to_s).to eq("#{8.to_bson.to_s}testing#{BSON::NULL_BYTE}")
        end

        it 'increments the write position by length + 5' do
          expect(modified.write_position).to eq(12)
        end
      end
    end

    context 'when the buffer needs to be expanded' do

      let(:string) do
        300.times.inject(""){ |s, i| s << "#{i}" }
      end

      context 'when no bytes exist in the buffer' do

        let!(:modified) do
          buffer.put_string(string)
        end

        it 'appends the string to the byte buffer' do
          expect(modified.to_s).to eq("#{(string.bytesize + 1).to_bson.to_s}#{string}#{BSON::NULL_BYTE}")
        end

        it 'increments the write position by length + 5' do
          expect(modified.write_position).to eq(string.bytesize + 5)
        end
      end

      context 'when bytes exist in the buffer' do

        let!(:modified) do
          buffer.put_int32(4).put_string(string)
        end

        it 'appends the string to the byte buffer' do
          expect(modified.to_s).to eq(
            "#{[ 4 ].pack(BSON::Int32::PACK)}#{(string.bytesize + 1).to_bson.to_s}#{string}#{BSON::NULL_BYTE}"
          )
        end

        it 'increments the write position by length + 5' do
          expect(modified.write_position).to eq(string.bytesize + 9)
        end
      end
    end

    context 'when string is in an encoding other than utf-8' do
      let(:string) do
        # "\xfe"
        Utils.make_byte_string([254], 'iso-8859-1')
      end

      let(:expected) do
        # \xc3\xbe == \u00fe
        Utils.make_byte_string([3, 0, 0, 0, 0xc3, 0xbe, 0])
      end

      it 'is written as utf-8' do
        expect(modified.to_s).to eq(expected)
      end
    end
  end

  describe '#put_cstring' do

    let(:modified) do
      buffer.put_cstring(string)
    end

    it_behaves_like 'bson string writer'

    context 'when argument is a string' do
      context 'when the string is valid' do

        let!(:modified) do
          buffer.put_cstring('testing')
        end

        it 'appends the string plus null byte to the byte buffer' do
          expect(modified.to_s).to eq("testing#{BSON::NULL_BYTE}")
        end

        it 'increments the write position by the length + 1' do
          expect(modified.write_position).to eq(8)
        end

        it 'mutates receiver' do
          modified
          expect(buffer.write_position).to eq(8)
        end
      end

      context "when the string contains a null byte" do

        let(:string) do
          "test#{BSON::NULL_BYTE}ing"
        end

        it 'raises ArgumentError' do
          expect {
            modified
          }.to raise_error(ArgumentError, /String .* contains null bytes/)
        end
      end

      context 'when string is in an encoding other than utf-8' do
        let(:string) do
          # "\xfe"
          Utils.make_byte_string([254], 'iso-8859-1')
        end

        let(:expected) do
          # \xc3\xbe == \u00fe
          # No length prefix
          Utils.make_byte_string([0xc3, 0xbe, 0])
        end

        it 'is written as utf-8' do
          expect(modified.to_s).to eq(expected)
        end
      end
    end

    context 'when argument is a symbol' do
      let(:modified) do
        buffer.put_cstring(:testing)
      end

      it 'writes' do
        expect(modified.to_s).to eq("testing#{BSON::NULL_BYTE}")
      end

      it 'increments the write position by the length + 1' do
        expect(modified.write_position).to eq(8)
      end

      it 'mutates receiver' do
        modified
        expect(buffer.write_position).to eq(8)
      end

      context 'when symbol includes a null byte' do
        let(:modified) do
          buffer.put_cstring(:"tes\x00ing")
        end

        it 'raises ArgumentError' do
          expect {
            modified
          }.to raise_error(ArgumentError, /String .* contains null bytes/)
        end

        it 'does not change write position' do
          begin
            buffer.put_cstring(:"tes\x00ing")
          rescue ArgumentError
          end

          expect(buffer.write_position).to eq(0)
        end
      end
    end

    context 'when argument is a Fixnum' do
      let(:modified) do
        buffer.put_cstring(1234)
      end

      it 'writes' do
        expect(modified.to_s).to eq("1234#{BSON::NULL_BYTE}")
      end

      it 'increments the write position by the length + 1' do
        expect(modified.write_position).to eq(5)
      end
    end

    context 'when argument is of an unsupported type' do
      let(:modified) do
        buffer.put_cstring(1234.0)
      end

      it 'raises TypeError' do
        expect do
          modified
        end.to raise_error(TypeError, /Invalid type for put_cstring/)
      end

      it 'does not change write position' do
        begin
          buffer.put_cstring(1234.0)
        rescue TypeError
        end

        expect(buffer.write_position).to eq(0)
      end
    end
  end

  describe '#put_symbol' do
    context 'normal symbol' do
      let(:modified) do
        buffer.put_symbol(:hello)
      end

      it 'writes the symbol as string' do
        expect(modified.to_s).to eq("\x06\x00\x00\x00hello\x00")
      end

      it 'advances write position' do
        # 4 byte length + 5 byte string + null byte
        expect(modified.write_position).to eq(10)
      end
    end

    context 'symbol with null byte' do
      let(:modified) do
        buffer.put_symbol(:"he\x00lo")
      end

      it 'writes the symbol as string' do
        expect(modified.to_s).to eq("\x06\x00\x00\x00he\x00lo\x00")
      end

      it 'advances write position' do
        # 4 byte length + 5 byte string + null byte
        expect(modified.write_position).to eq(10)
      end
    end

    context 'when symbol is not valid utf-8' do
      let(:symbol) do
        Utils.make_byte_string([254, 0, 255]).to_sym
      end

      let(:modified) do
        buffer.put_symbol(symbol)
      end

      it 'raises EncodingError' do
        # Precise exception classes and messages differ between MRI and JRuby
        expect do
          modified
        end.to raise_error(EncodingError)
      end
    end
  end

  describe '#put_double' do

    let(:modified) do
      buffer.put_double(1.2332)
    end

    it 'appends the double to the buffer' do
      expect(modified.to_s).to eq([ 1.2332 ].pack(Float::PACK))
    end

    it 'increments the write position by 8' do
      expect(modified.write_position).to eq(8)
    end

    context 'when argument is an integer' do

      let(:modified) do
        buffer.put_double(3)
      end

      it 'writes a double' do
        expect(modified.to_s).to eq([ 3 ].pack(Float::PACK))
      end

      it 'increments the write position by 8' do
        expect(modified.write_position).to eq(8)
      end
    end

    context 'when argument is a BigNum' do
      let(:value) { 123456789012345678901234567890 }

      let(:modified) do
        buffer.put_double(value)
      end

      let(:actual) do
        described_class.new(modified.to_s).get_double
      end

      it 'writes a double' do
        expect(actual).to be_within(1).of(value)
      end

      it 'increments the write position by 8' do
        expect(modified.write_position).to eq(8)
      end
    end

    context 'when argument is a string' do

      let(:modified) do
        buffer.put_double("hello")
      end

      it 'raises TypeError' do
        expect do
          modified
        end.to raise_error(TypeError, /no implicit conversion to float from string|ClassCastException:.*RubyString cannot be cast to.*RubyFloat/)
        expect(buffer.write_position).to eq(0)
      end
    end
  end

  describe '#put_int32' do

    context 'when the integer is 32 bit' do

      context 'when the integer is positive' do

        let!(:modified) do
          buffer.put_int32(Integer::MAX_32BIT - 1)
        end

        let(:expected) do
          [ Integer::MAX_32BIT - 1 ].pack(BSON::Int32::PACK)
        end

        it 'appends the int32 to the byte buffer' do
          expect(modified.to_s).to eq(expected)
        end

        it 'increments the write position by 4' do
          expect(modified.write_position).to eq(4)
        end
      end

      context 'when the integer is negative' do

        let!(:modified) do
          buffer.put_int32(Integer::MIN_32BIT + 1)
        end

        let(:expected) do
          [ Integer::MIN_32BIT + 1 ].pack(BSON::Int32::PACK)
        end

        it 'appends the int32 to the byte buffer' do
          expect(modified.to_s).to eq(expected)
        end

        it 'increments the write position by 4' do
          expect(modified.write_position).to eq(4)
        end
      end

      context 'when the integer is not 32 bit' do

        it 'raises an exception' do
          expect {
            buffer.put_int32(Integer::MAX_64BIT - 1)
          }.to raise_error(RangeError)
        end
      end
    end

    context 'when argument is a float' do

      let(:modified) do
        buffer.put_int32(4.934)
      end

        let(:expected) do
          [ 4 ].pack(BSON::Int32::PACK)
        end

      it 'appends the int32 to the byte buffer' do
        expect(modified.to_s).to eq(expected)
      end

      it 'increments the write position by 4' do
        expect(modified.write_position).to eq(4)
      end
    end
  end

  describe '#put_uint32' do
    context 'when argument is a float' do
      it 'raises an Argument Error' do
        expect{ buffer.put_uint32(4.934) }.to raise_error(ArgumentError, "put_uint32: incorrect type: float, expected: integer")
      end
    end
    
    context 'when number is in range' do 
      let(:modified) do
        buffer.put_uint32(5)
      end

      it 'returns gets the correct number from the buffer' do
        expect(modified.get_uint32).to eq(5)
      end

      it 'returns the length of the buffer' do
        expect(modified.length).to eq(4)
      end
    end

    context 'when number is 0' do 
      let(:modified) do
        buffer.put_uint32(0)
      end

      it 'returns gets the correct number from the buffer' do
        expect(modified.get_uint32).to eq(0)
      end

      it 'returns the length of the buffer' do
        expect(modified.length).to eq(4)
      end
    end

    context 'when number doesn\'t fit in signed int32' do 
      let(:modified) do
        buffer.put_uint32(4294967295)
      end

      let(:expected) do
        [ 4294967295 ].pack(BSON::Int32::PACK)
      end

      it 'appends the int32 to the byte buffer' do
        expect(modified.to_s).to eq(expected)
      end

      it 'get returns correct number' do
        expect(modified.get_uint32).to eq(4294967295)
      end

      it 'returns the length of the buffer' do
        expect(modified.length).to eq(4)
      end
    end

    context 'when number is 2^31' do 
      let(:modified) do
        buffer.put_uint32(2147483648)
      end

      it 'returns gets the correct number from the buffer' do
        expect(modified.get_uint32).to eq(2147483648)
      end

      it 'returns the length of the buffer' do
        expect(modified.length).to eq(4)
      end
    end

    context 'when number is 2^31-1' do 
      let(:modified) do
        buffer.put_uint32(2147483647)
      end

      it 'returns gets the correct number from the buffer' do
        expect(modified.get_uint32).to eq(2147483647)
      end

      it 'returns the length of the buffer' do
        expect(modified.length).to eq(4)
      end
    end

    context 'when number is not in range' do 
      it 'raises error on out of top range' do
        expect{ buffer.put_uint32(4294967296) }.to raise_error(RangeError, "Number 4294967296 is out of range [0, 2^32)")
      end

      it 'raises error on out of bottom range' do
        expect{ buffer.put_uint32(-1) }.to raise_error(RangeError, "Number -1 is out of range [0, 2^32)")
      end
    end
  end

  describe '#put_int64' do

    context 'when the integer is 64 bit' do

      context 'when the integer is positive' do

        let!(:modified) do
          buffer.put_int64(Integer::MAX_64BIT - 1)
        end

        let(:expected) do
          [ Integer::MAX_64BIT - 1 ].pack(BSON::Int64::PACK)
        end

        it 'appends the int64 to the byte buffer' do
          expect(modified.to_s).to eq(expected)
        end

        it 'increments the write position by 8' do
          expect(modified.write_position).to eq(8)
        end
      end

      context 'when the integer is negative' do

        let!(:modified) do
          buffer.put_int64(Integer::MIN_64BIT + 1)
        end

        let(:expected) do
          [ Integer::MIN_64BIT + 1 ].pack(BSON::Int64::PACK)
        end

        it 'appends the int64 to the byte buffer' do
          expect(modified.to_s).to eq(expected)
        end

        it 'increments the write position by 8' do
          expect(modified.write_position).to eq(8)
        end
      end

      context 'when the integer is larger than 64 bit' do

        it 'raises an exception' do
          expect {
            buffer.put_int64(Integer::MAX_64BIT + 1)
          }.to raise_error(RangeError)
        end
      end
    end

    context 'when integer fits in 32 bits' do
      let(:modified) do
        buffer.put_int64(1)
      end

      it 'increments the write position by 8' do
        expect(modified.write_position).to eq(8)
      end
    end

    context 'when argument is a float' do

      let(:modified) do
        buffer.put_int64(4.934)
      end

        let(:expected) do
          [ 4 ].pack(BSON::Int64::PACK)
        end

      it 'appends the int64 to the byte buffer' do
        expect(modified.to_s).to eq(expected)
      end

      it 'increments the write position by 8' do
        expect(modified.write_position).to eq(8)
      end
    end
  end

  describe '#replace_int32' do

    let(:exp_0) do
      [ 0 ].pack(BSON::Int32::PACK)
    end

    let(:exp_first) do
      [ 5 ].pack(BSON::Int32::PACK)
    end

    let(:exp_second) do
      [ 4 ].pack(BSON::Int32::PACK)
    end

    let(:exp_42) do
      [ 42 ].pack(BSON::Int32::PACK)
    end

    let(:modified) do
      buffer.replace_int32(0, 5)
    end

    context 'when there is sufficient data in buffer' do

      before do
        buffer.put_int32(0).put_int32(4)
      end

      it 'replaces the int32 at the location' do
        expect(modified.to_s).to eq("#{exp_first}#{exp_second}")
      end

      context 'when the position is negative' do

        let(:modified) do
          buffer.replace_int32(-1, 5)
        end

        it 'raises ArgumentError' do
          expect do
            modified
          end.to raise_error(ArgumentError, /Position.*cannot be negative/)
        end
      end

      context 'when the position is 4 bytes prior to write position' do

        let(:modified) do
          buffer.replace_int32(4, 42)
        end

        it 'replaces the int32 at the location' do
          expect(modified.to_s).to eq("#{exp_0}#{exp_42}")
        end
      end

      context 'when the position exceeds allowed range' do

        let(:modified) do
          # Buffer has 8 bytes but we can only write up to position 4
          buffer.replace_int32(5, 42)
        end

        it 'raises ArgumentError' do
          expect do
            modified
          end.to raise_error(ArgumentError, /Position.*is out of bounds/)
        end
      end
    end

    context 'when there is insufficient data in buffer' do

      before do
        buffer.put_bytes("aa")
      end

      let(:modified) do
        buffer.replace_int32(1, 42)
      end

      it 'raises ArgumentError' do
        expect do
          modified
        end.to raise_error(ArgumentError, /Buffer does not have enough data/)
      end
    end
  end
end