#![cfg_attr(not(feature="std"), allow(unused_imports))]

use super::combined_alloc::BrotliAlloc;
use super::encode::{BrotliEncoderCreateInstance, BrotliEncoderDestroyInstance,
                    BrotliEncoderParameter, BrotliEncoderSetParameter, BrotliEncoderOperation,
                    BrotliEncoderStateStruct, BrotliEncoderCompressStream, BrotliEncoderIsFinished};
use super::backward_references::BrotliEncoderParams;
use super::interface;
use brotli_decompressor::CustomRead;

#[cfg(feature="std")]
pub use brotli_decompressor::{IntoIoReader, IoReaderWrapper, IoWriterWrapper};

pub use alloc::{AllocatedStackMemory, Allocator, SliceWrapper, SliceWrapperMut, StackAllocator};
#[cfg(feature="std")]
pub use alloc_stdlib::StandardAlloc;
#[cfg(feature="std")]
use std::io;

#[cfg(feature="std")]
use std::io::{Read, Error, ErrorKind};



#[cfg(feature="std")]
pub struct CompressorReaderCustomAlloc<R: Read,
                                       BufferType : SliceWrapperMut<u8>,
                                       Alloc: BrotliAlloc> (
    CompressorReaderCustomIo<io::Error,
                             IntoIoReader<R>,
                             BufferType,
                             Alloc>);


#[cfg(feature="std")]
impl<R: Read,
     BufferType : SliceWrapperMut<u8>,
     Alloc: BrotliAlloc>
    CompressorReaderCustomAlloc<R, BufferType, Alloc>
    {

    pub fn new(r: R, buffer : BufferType,
               alloc: Alloc,
               q: u32,
               lgwin: u32) -> Self {
        CompressorReaderCustomAlloc::<R, BufferType, Alloc>(
          CompressorReaderCustomIo::<Error,
                                 IntoIoReader<R>,
                                 BufferType,
                                 Alloc>::new(
              IntoIoReader::<R>(r),
              buffer,
              alloc,
              Error::new(ErrorKind::InvalidData,
                         "Invalid Data"),
              q, lgwin))
    }

    pub fn get_ref(&self) -> &R {
        &self.0.get_ref().0
    }
    pub fn into_inner(self) -> R {
        self.0.into_inner().0
    }
}

#[cfg(feature="std")]
impl<R: Read,
     BufferType: SliceWrapperMut<u8>,
     Alloc: BrotliAlloc>
    Read for CompressorReaderCustomAlloc<R, BufferType,
                                         Alloc> {
  	fn read(&mut self, buf: &mut [u8]) -> Result<usize, Error> {
       self.0.read(buf)
    }
}

#[cfg(feature="std")]
pub struct CompressorReader<R: Read>(CompressorReaderCustomAlloc<R,
                                     <StandardAlloc as Allocator<u8>>::AllocatedMemory,
                                     StandardAlloc>);


#[cfg(feature="std")]
impl<R: Read> CompressorReader<R> {
  pub fn new(r: R, buffer_size: usize, q: u32, lgwin: u32) -> Self {
    let mut alloc = StandardAlloc::default();
    let buffer = <StandardAlloc as Allocator<u8>>::alloc_cell(&mut alloc,
                                                              if buffer_size == 0 { 4096} else {buffer_size});
    CompressorReader::<R>(CompressorReaderCustomAlloc::new(r,
                                                           buffer,
                                                           alloc,
                                                           q,
                                                           lgwin))
  }

  pub fn with_params(r: R, buffer_size: usize, params: &BrotliEncoderParams) -> Self {
    let mut reader = Self::new(r, buffer_size, params.quality as u32, params.lgwin as u32);
    (reader.0).0.state.0.params = params.clone();
    reader
  }

  pub fn get_ref(&self) -> &R {
      self.0.get_ref()
  }
  pub fn into_inner(self) -> R {
    self.0.into_inner()
  }
}



#[cfg(feature="std")]
impl<R: Read> Read for CompressorReader<R> {
  fn read(&mut self, buf: &mut [u8]) -> Result<usize, Error> {
    self.0.read(buf)
  }
}

pub struct CompressorReaderCustomIo<ErrType,
                                    R: CustomRead<ErrType>,
                                    BufferType: SliceWrapperMut<u8>,
                                    Alloc: BrotliAlloc>
{
  input_buffer: BufferType,
  total_out: Option<usize>,
  input_offset: usize,
  input_len: usize,
  input: R,
  input_eof: bool,
  error_if_invalid_data: Option<ErrType>,
  state: StateWrapper<Alloc>,
}
struct StateWrapper<Alloc:BrotliAlloc>(BrotliEncoderStateStruct<Alloc>);

impl<Alloc: BrotliAlloc> Drop for StateWrapper <Alloc> {
    fn drop(&mut self) {
        BrotliEncoderDestroyInstance(&mut self.0);
    }
}

impl<ErrType,
     R: CustomRead<ErrType>,
     BufferType : SliceWrapperMut<u8>,
     Alloc: BrotliAlloc>
CompressorReaderCustomIo<ErrType, R, BufferType, Alloc>
{

    pub fn new(r: R, buffer : BufferType,
                              alloc : Alloc,
               invalid_data_error_type : ErrType,
               q: u32,
               lgwin: u32) -> Self {
        let mut ret = CompressorReaderCustomIo{
            input_buffer : buffer,
            total_out : Some(0),
            input_offset : 0,
            input_len : 0,
            input_eof : false,
            input: r,
            state : StateWrapper(BrotliEncoderCreateInstance(alloc)),
            error_if_invalid_data : Some(invalid_data_error_type),
        };
        BrotliEncoderSetParameter(&mut ret.state.0,
                                  BrotliEncoderParameter::BROTLI_PARAM_QUALITY,
                                  q as (u32));
        BrotliEncoderSetParameter(&mut ret.state.0,
                                  BrotliEncoderParameter::BROTLI_PARAM_LGWIN,
                                  lgwin as (u32));

        ret
    }
    pub fn copy_to_front(&mut self) {
        let avail_in = self.input_len - self.input_offset;
        if self.input_offset == self.input_buffer.slice_mut().len() {
            self.input_offset = 0;
            self.input_len = 0;
        } else if self.input_offset + 256 > self.input_buffer.slice_mut().len() && avail_in < self.input_offset {
            let (first, second) = self.input_buffer.slice_mut().split_at_mut(self.input_offset);
            first[0..avail_in].clone_from_slice(&second[0..avail_in]);
            self.input_len -= self.input_offset;
            self.input_offset = 0;
        }
    }
    pub fn into_inner(self) -> R{
      match self {
        CompressorReaderCustomIo {
          input_buffer:_ib,
          total_out:_to,
          input_offset: _io,
          input_len: _len,
          input,
          input_eof:_ieof,
          error_if_invalid_data: _eiid,
          state: _state,
        } => {
          input
        }
      }
    }
    pub fn get_ref(&self) -> &R {
        &self.input
    }
}
impl<ErrType,
     R: CustomRead<ErrType>,
     BufferType : SliceWrapperMut<u8>,
     Alloc: BrotliAlloc> CustomRead<ErrType> for
CompressorReaderCustomIo<ErrType, R, BufferType, Alloc> {
    fn read(&mut self, buf: &mut [u8]) -> Result<usize, ErrType > {
        let mut nop_callback = |_data:&mut interface::PredictionModeContextMap<interface::InputReferenceMut>,
                              _cmds: &mut [interface::StaticCommand],
                              _mb: interface::InputPair, _mfv: &mut Alloc|();
        let mut output_offset : usize = 0;
        let mut avail_out = buf.len();
        let mut avail_in = self.input_len - self.input_offset;
        while output_offset == 0 {
            if self.input_len < self.input_buffer.slice_mut().len() && !self.input_eof {
                match self.input.read(&mut self.input_buffer.slice_mut()[self.input_len..]) {
                    Err(e) => return Err(e),
                    Ok(size) => if size == 0 {
                        self.input_eof = true;
                    }else {
                        self.input_len += size;
                        avail_in = self.input_len - self.input_offset;
                    },
                }
            }
            let op : BrotliEncoderOperation;
            if avail_in == 0 {
                op = BrotliEncoderOperation::BROTLI_OPERATION_FINISH;
            } else {
                op = BrotliEncoderOperation::BROTLI_OPERATION_PROCESS;
            }
            let ret = BrotliEncoderCompressStream(
                &mut self.state.0,
                op,
                &mut avail_in,
                &self.input_buffer.slice_mut()[..],
                &mut self.input_offset,
                &mut avail_out,
                buf,
                &mut output_offset,
                &mut self.total_out,
                &mut nop_callback);
            if avail_in == 0 {
                self.copy_to_front();
            }
            if ret <= 0 {
                return Err(self.error_if_invalid_data.take().unwrap());
            }
            let fin = BrotliEncoderIsFinished(&mut self.state.0);
            if fin != 0 {
                break;
            }
        }
        Ok(output_offset)
    }
}