#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>

#include "audio.h"
#include "audio_internal.h"

typedef struct _SinkFileContext {
    FILE *fp;
} SinkFileContext;

AudioPipelineStatus sink_file_push(AudioPipelineElement *self, AudioBuffer *buffer) {
    SinkFileContext *context = (SinkFileContext *)self->ctx;

    size_t bytes = fwrite(buffer->data, 1, buffer->buf_size, context->fp);

    return (bytes != buffer->buf_size) ? PipelineError : PipelineRunning;
}

AudioPipelineStatus sink_file_link(AudioPipelineElement *self, AudioPipelineElement *source) {
    SinkFileContext *context = (SinkFileContext *)self->ctx;

    if (context->fp != NULL) {
        fseek(context->fp, 0, SEEK_SET);
        if (ftruncate(fileno(context->fp), 0) != 0) {
            fprintf(stderr, "WARN: ftruncate failed with %d\n", errno);
        }
    }
       
    source->next = self;

    return PipelineStopped;
}

char *sink_file_describe(AudioPipelineElement *self) {
    return "file sink";
}

void sink_file_destroy(AudioPipelineElement *self) {
    SinkFileContext *context = (SinkFileContext *)self->ctx;

    fclose(context->fp);
    free(self->ctx);
    free(self);
}

AudioPipelineElement *audio_sink_file(char *filename) {
    AudioPipelineElement *self = calloc(1, sizeof(AudioPipelineElement));
    SinkFileContext *context = calloc(1, sizeof(SinkFileContext));
   
    context->fp = fopen(filename, "wb");
    if (context->fp == NULL) {
        fprintf(stderr, "ERROR: Cannot open file %s, errno=%d", filename, errno);
        free(context);
        free(self);
        return NULL;
    }

    self->ctx = context;
    self->describe = sink_file_describe;
    self->start = sink_nop;
    self->reset = sink_nop;
    self->stop = sink_nop;
    self->push = sink_file_push;
    self->link = sink_file_link;
    self->destroy = sink_file_destroy;
    self->type = AudioElementSink;
    
    return self;
}