/*
 * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <AK/MemoryStream.h>
#include <AK/NumericLimits.h>
#include <AK/OwnPtr.h>
#include <LibAudio/WavLoader.h>
#include <LibCore/File.h>
#include <LibCore/IODeviceStreamReader.h>

namespace Audio {

WavLoader::WavLoader(const StringView& path)
    : m_file(Core::File::construct(path))
{
    if (!m_file->open(Core::IODevice::ReadOnly)) {
        m_error_string = String::formatted("Can't open file: {}", m_file->error_string());
        return;
    }

    if (!parse_header())
        return;

    m_resampler = make<ResampleHelper>(m_sample_rate, 44100);
}

RefPtr<Buffer> WavLoader::get_more_samples(size_t max_bytes_to_read_from_input)
{
#ifdef AWAVLOADER_DEBUG
    dbgln("Read WAV of format PCM with num_channels {} sample rate {}, bits per sample {}", m_num_channels, m_sample_rate, m_bits_per_sample);
#endif

    auto raw_samples = m_file->read(max_bytes_to_read_from_input);
    if (raw_samples.is_empty())
        return nullptr;

    auto buffer = Buffer::from_pcm_data(raw_samples, *m_resampler, m_num_channels, m_bits_per_sample);
    //Buffer contains normalized samples, but m_loaded_samples should contain the amount of actually loaded samples
    m_loaded_samples += static_cast<int>(max_bytes_to_read_from_input) / (m_num_channels * (m_bits_per_sample / 8));
    m_loaded_samples = min(m_total_samples, m_loaded_samples);
    return buffer;
}

void WavLoader::seek(const int position)
{
    if (position < 0 || position > m_total_samples)
        return;

    m_loaded_samples = position;
    m_file->seek(position * m_num_channels * (m_bits_per_sample / 8));
}

void WavLoader::reset()
{
    seek(0);
}

bool WavLoader::parse_header()
{
    Core::IODeviceStreamReader stream(*m_file);

#define CHECK_OK(msg)                                                              \
    do {                                                                           \
        if (stream.handle_read_failure()) {                                        \
            m_error_string = String::formatted("Premature stream EOF at {}", msg); \
            return {};                                                             \
        }                                                                          \
        if (!ok) {                                                                 \
            m_error_string = String::formatted("Parsing failed: {}", msg);         \
            return {};                                                             \
        } else {                                                                   \
            dbgln("{} is OK!", msg);                                               \
        }                                                                          \
    } while (0);

    bool ok = true;
    u32 riff;
    stream >> riff;
    ok = ok && riff == 0x46464952; // "RIFF"
    CHECK_OK("RIFF header");

    u32 sz;
    stream >> sz;
    ok = ok && sz < 1024 * 1024 * 1024; // arbitrary
    CHECK_OK("File size");
    ASSERT(sz < 1024 * 1024 * 1024);

    u32 wave;
    stream >> wave;
    ok = ok && wave == 0x45564157; // "WAVE"
    CHECK_OK("WAVE header");

    u32 fmt_id;
    stream >> fmt_id;
    ok = ok && fmt_id == 0x20746D66; // "FMT"
    CHECK_OK("FMT header");

    u32 fmt_size;
    stream >> fmt_size;
    ok = ok && fmt_size == 16;
    CHECK_OK("FMT size");
    ASSERT(fmt_size == 16);

    u16 audio_format;
    stream >> audio_format;
    CHECK_OK("Audio format");     // incomplete read check
    ok = ok && audio_format == 1; // WAVE_FORMAT_PCM
    ASSERT(audio_format == 1);
    CHECK_OK("Audio format"); // value check

    stream >> m_num_channels;
    ok = ok && (m_num_channels == 1 || m_num_channels == 2);
    CHECK_OK("Channel count");

    stream >> m_sample_rate;
    CHECK_OK("Sample rate");

    u32 byte_rate;
    stream >> byte_rate;
    CHECK_OK("Byte rate");

    u16 block_align;
    stream >> block_align;
    CHECK_OK("Block align");

    stream >> m_bits_per_sample;
    CHECK_OK("Bits per sample"); // incomplete read check
    ok = ok && (m_bits_per_sample == 8 || m_bits_per_sample == 16 || m_bits_per_sample == 24);
    ASSERT(m_bits_per_sample == 8 || m_bits_per_sample == 16 || m_bits_per_sample == 24);
    CHECK_OK("Bits per sample"); // value check

    // Read chunks until we find DATA
    bool found_data = false;
    u32 data_sz = 0;
    u8 search_byte = 0;
    while (true) {
        stream >> search_byte;
        CHECK_OK("Reading byte searching for data");
        if (search_byte != 0x64) //D
            continue;

        stream >> search_byte;
        CHECK_OK("Reading next byte searching for data");
        if (search_byte != 0x61) //A
            continue;

        u16 search_remaining = 0;
        stream >> search_remaining;
        CHECK_OK("Reading remaining bytes searching for data");
        if (search_remaining != 0x6174) //TA
            continue;

        stream >> data_sz;
        found_data = true;
        break;
    }

    ok = ok && found_data;
    CHECK_OK("Found no data chunk");
    ASSERT(found_data);

    ok = ok && data_sz < INT32_MAX;
    CHECK_OK("Data was too large");

    int bytes_per_sample = (m_bits_per_sample / 8) * m_num_channels;
    m_total_samples = data_sz / bytes_per_sample;

    // Just make sure we're good before we read the data...
    ASSERT(!stream.handle_read_failure());

    return true;
}

ResampleHelper::ResampleHelper(double source, double target)
    : m_ratio(source / target)
{
}

void ResampleHelper::process_sample(double sample_l, double sample_r)
{
    m_last_sample_l = sample_l;
    m_last_sample_r = sample_r;
    m_current_ratio += 1;
}

bool ResampleHelper::read_sample(double& next_l, double& next_r)
{
    if (m_current_ratio > 0) {
        m_current_ratio -= m_ratio;
        next_l = m_last_sample_l;
        next_r = m_last_sample_r;
        return true;
    }

    return false;
}

template<typename SampleReader>
static void read_samples_from_stream(InputMemoryStream& stream, SampleReader read_sample, Vector<Sample>& samples, ResampleHelper& resampler, int num_channels)
{
    double norm_l = 0;
    double norm_r = 0;

    switch (num_channels) {
    case 1:
        for (;;) {
            while (resampler.read_sample(norm_l, norm_r)) {
                samples.append(Sample(norm_l));
            }
            norm_l = read_sample(stream);

            if (stream.handle_any_error()) {
                break;
            }
            resampler.process_sample(norm_l, norm_r);
        }
        break;
    case 2:
        for (;;) {
            while (resampler.read_sample(norm_l, norm_r)) {
                samples.append(Sample(norm_l, norm_r));
            }
            norm_l = read_sample(stream);
            norm_r = read_sample(stream);

            if (stream.handle_any_error()) {
                break;
            }
            resampler.process_sample(norm_l, norm_r);
        }
        break;
    default:
        ASSERT_NOT_REACHED();
    }
}

static double read_norm_sample_24(InputMemoryStream& stream)
{
    u8 byte = 0;
    stream >> byte;
    u32 sample1 = byte;
    stream >> byte;
    u32 sample2 = byte;
    stream >> byte;
    u32 sample3 = byte;

    i32 value = 0;
    value = sample1 << 8;
    value |= (sample2 << 16);
    value |= (sample3 << 24);
    return double(value) / NumericLimits<i32>::max();
}

static double read_norm_sample_16(InputMemoryStream& stream)
{
    LittleEndian<i16> sample;
    stream >> sample;
    return double(sample) / NumericLimits<i16>::max();
}

static double read_norm_sample_8(InputMemoryStream& stream)
{
    u8 sample = 0;
    stream >> sample;
    return double(sample) / NumericLimits<u8>::max();
}

RefPtr<Buffer> Buffer::from_pcm_data(ReadonlyBytes data, ResampleHelper& resampler, int num_channels, int bits_per_sample)
{
    InputMemoryStream stream { data };
    Vector<Sample> fdata;
    fdata.ensure_capacity(data.size() / (bits_per_sample / 8));
#ifdef AWAVLOADER_DEBUG
    dbgln("Reading {} bits and {} channels, total bytes: {}", bits_per_sample, num_channels, data.size());
#endif

    switch (bits_per_sample) {
    case 8:
        read_samples_from_stream(stream, read_norm_sample_8, fdata, resampler, num_channels);
        break;
    case 16:
        read_samples_from_stream(stream, read_norm_sample_16, fdata, resampler, num_channels);
        break;
    case 24:
        read_samples_from_stream(stream, read_norm_sample_24, fdata, resampler, num_channels);
        break;
    default:
        ASSERT_NOT_REACHED();
    }

    // We should handle this in a better way above, but for now --
    // just make sure we're good. Worst case we just write some 0s where they
    // don't belong.
    ASSERT(!stream.handle_any_error());

    return Buffer::create_with_samples(move(fdata));
}

}
