#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>

#include "audio.h"
#include "audio_internal.h"
#include "audio_demuxer_adts.h"
#include "deps/aac/neaacdec.h"

typedef struct _DecoderAACContext {
    AudioBuffer *outputBuffer;
    NeAACDecHandle decoder;
    NeAACDecFrameInfo frameInfo;
    bool initialized;
} DecoderAACContext;

AudioPipelineStatus decoder_aac_push(AudioPipelineElement *self, AudioBuffer *buffer) {
    DecoderAACContext *context = (DecoderAACContext *)self->ctx;
    void *end;
    
    if (!context->initialized) {
        unsigned long samplerate;
        unsigned char channels;
        char result = NeAACDecInit(context->decoder, buffer->data, buffer->buf_size, &samplerate, &channels);
        if (result != 0) {
            fprintf(stderr, "ERROR: Failed to initialize AAC decoder, retrying on next frame\n");
            return PipelineBuffering;
        }
        context->initialized = true;
    }

decode:
    end = NeAACDecDecode2(context->decoder, &context->frameInfo, buffer->data, buffer->buf_size, (void **)&context->outputBuffer->data, context->outputBuffer->buf_size);
    if (end == NULL && context->frameInfo.error == 27) {
        // sample buffer was too small, reallocate
        uint32_t sz = context->outputBuffer->buf_size;
        free_audio_buffer(context->outputBuffer);
        context->outputBuffer = alloc_audio_buffer(sz * 2);
        goto decode;
    }
    
    bool relink_needed = (context->frameInfo.channels != self->channels) || (context->frameInfo.samplerate != self->sample_rate);
    
    if (relink_needed) {
        self->channels = context->frameInfo.channels;
        self->sample_rate = (uint32_t)context->frameInfo.samplerate;
        AudioPipelineStatus result = self->next->link(self->next, self);
        if (result != PipelineStopped) {
            fprintf(stderr, "ERROR: Re-link failed\n");
            return PipelineError;
        }
    }
    
    // run next element of the pipeline
    if (context->frameInfo.samples > 0) {
        uint32_t buf_sz = context->outputBuffer->buf_size;
        context->outputBuffer->buf_size = self->bits_per_sample / 8 * (uint32_t)context->frameInfo.samples;
        AudioPipelineStatus ret = self->next->push(self->next, context->outputBuffer);
        if ((ret != PipelineRunning) && (ret != PipelineBuffering)) {
            return ret;
        }
        context->outputBuffer->buf_size = buf_sz;
        
        return PipelineRunning;
    }
    
    return PipelineBuffering;
}

AudioPipelineStatus decoder_aac_link(AudioPipelineElement *self, AudioPipelineElement *source) {
    if ((source->sample_rate != 0) || (source->channels != 0) || (source->bits_per_sample != 0) || (!((source->type == AudioElementSource) || (source->type == AudioElementDemuxer)))) {
        fprintf(stderr, "ERROR: AAC decoder can only link to a data source, not %s!\n", source->describe(source));
        return PipelineError;
    }

    source->next = self;
    return PipelineStopped;
}

char *decoder_aac_describe(AudioPipelineElement *self) {
    return "libfaad2 AAC decoder";
}

void decoder_aac_destroy(AudioPipelineElement *self) {
    DecoderAACContext *context = (DecoderAACContext *)self->ctx;
    if (context->outputBuffer) {
        free_audio_buffer(context->outputBuffer);
    }
    if (context->decoder) {
        NeAACDecClose(context->decoder);
    }
    
    free(context);
    free(self);
}

AudioPipelineElement *audio_decoder_aac(void) {
    AudioPipelineElement *self = calloc(1, sizeof(AudioPipelineElement));
    DecoderAACContext *context = calloc(1, sizeof(DecoderAACContext));

    context->decoder = NeAACDecOpen();
    NeAACDecConfigurationPtr config = NeAACDecGetCurrentConfiguration(context->decoder);
    config->defSampleRate = 48000;
    config->outputFormat = FAAD_FMT_16BIT;
    config->defObjectType = LC;
    config->downMatrix = 1; // mix to 2 channels;
    NeAACDecSetConfiguration(context->decoder, config);
    self->bits_per_sample = 16;
    self->channels = 2;
    
    context->outputBuffer = alloc_audio_buffer(1024 * 2 * 2); // 2 bytes per sample, 1024 samples per frame plus scratch space (*2)

    self->ctx = context;
    self->describe = decoder_aac_describe;
    self->start = filter_start_nop;
    self->reset = filter_reset_nop;
    self->stop = filter_stop_nop;
    self->push = decoder_aac_push;
    self->link = decoder_aac_link;
    self->destroy = decoder_aac_destroy;
    self->type = AudioElementDecoder;
    
    return self;
}