#include <assert.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>

#include "bipbuffer.h"

#define NUM_SAMPLES (5)

typedef struct io_cb io_cb_t;

typedef struct {
    io_cb_t *io;
    int dimensions;
} arg_t;

typedef void (*data_handler_t)( arg_t *io );

struct io_cb {
    void *data;
    size_t size;
    data_handler_t prepare_read;
    data_handler_t commit_read;
    data_handler_t prepare_write;
    data_handler_t commit_write;
};

void dummy_handler( arg_t *io ) {
    (void)io;
}

enum data_type_e {
    UINT8 = 0,
    INT16,
};

typedef struct {
    io_cb_t cb;
    int data_type;
    FILE *fd;
} file_io_t;

enum arguments_e {
    IN0 = 0,
    IN1,
    IN2,
    IN3,
};

typedef struct {
    void (*process)( arg_t args[] );
    int input_argc;
    int output_argc;
    arg_t args[];
} node_t;

void file_prepare_read_handler( arg_t *arg ) {
    file_io_t *io = (file_io_t*)arg->io;
    char value[128] = {0};
    char end;
    int result;
    FILE *fd = io->fd;
    uint8_t *outu8  = io->cb.data;
    int16_t *outi16 = io->cb.data;
    do {
        result = fscanf( fd, "%127[^,\n]", value );
        if( result == 0 ) {
            result = fscanf( fd, "%c", &end );
            if( end == '\n' ) {
                break;
            }
        } else {
            int number = atoi(value);
            switch( io->data_type ) {
                case INT16: {
                    *outi16++ = number;
                    io->cb.size += 2;
                    break;
                }
                case UINT8:
                default:
                    *outu8++ = number;
                    io->cb.size++;
                    break;
            }
            printf("%d\n", atoi(value));
        }
    } while(result != EOF);
}

void file_io_init( file_io_t *io, const char *filename ) {
    FILE *fd = fopen(filename, "r");
    io->fd = NULL;
    if( fd == NULL ) {
        perror("can't open file");
        return;
    }
    io->fd = fd;
    io_cb_t *cb = (io_cb_t*)io;
    cb->prepare_read = file_prepare_read_handler;
    cb->commit_read = dummy_handler;
    cb->prepare_write = dummy_handler;
    cb->commit_write = dummy_handler;
}

typedef struct {
    io_cb_t cb;
    bipbuf_t buf;
} buffer_io_t;


static void buffer_prepare_read_handler( arg_t *arg ) {
    printf("%s\n", __func__);
    buffer_io_t *io = (buffer_io_t*)arg->io;
    io_cb_t *cb = &io->cb;
    cb->data = bipbuf_peek( &io->buf, arg->dimensions );
    cb->size = arg->dimensions;
}

static void buffer_commit_read_handler( arg_t *arg ) {
    printf("%s\n", __func__);
    buffer_io_t *io = (buffer_io_t*)arg->io;
    io_cb_t *cb = &io->cb;
    bipbuf_poll( &io->buf, arg->dimensions );
    cb->data = NULL;
    cb->size = 0;
}

static void buffer_prepare_write_handler( arg_t *arg ) {
    printf("%s\n", __func__);
    buffer_io_t *io = (buffer_io_t*)arg->io;
    io_cb_t *cb = &io->cb;
    cb->data = bipbuf_reserve( &io->buf, arg->dimensions );
    cb->size = arg->dimensions;
}

static void buffer_commit_write_handler( arg_t *arg ) {
    printf("%s\n", __func__);
    buffer_io_t *io = (buffer_io_t*)arg->io;
    io_cb_t *cb = &io->cb;
    bipbuf_commit( &io->buf, arg->dimensions );
    cb->data = NULL;
    cb->size = 0;
}

void buffer_io_init( buffer_io_t *io, size_t size ) {
    bipbuf_init( &io->buf, size );
    io_cb_t *cb = &io->cb;
    cb->prepare_read = buffer_prepare_read_handler;
    cb->commit_read = buffer_commit_read_handler;
    cb->prepare_write = buffer_prepare_write_handler;
    cb->commit_write = buffer_commit_write_handler;
}


void simple( arg_t * __restrict args ) {
    printf("%s\n", __func__ );
    int16_t* __restrict in_t = args[0].io->data;
    int16_t* __restrict out_t = args[1].io->data;
    for( unsigned i=0; i<NUM_SAMPLES; i++ ) {
        *out_t++ = 1 + *in_t++;
    }
}

void process_node( node_t *node ) {
    int active_inputs = 0;
    int total_argc = node->input_argc + node->output_argc;
    printf("node: %p\n", node );
    for( int input = 0; input<node->input_argc; ++input ) {
        arg_t *arg = &node->args[input];
        io_cb_t *io = arg->io;
        assert( io->prepare_read != NULL );
        io->prepare_read( arg );

        if( io->size >= arg->dimensions ) {
            printf("node: %p input %d active\n", node, input );
            ++active_inputs;
        }
    }
    if(( active_inputs == node->input_argc ) && ( node->process != NULL )) {
        for( int output = node->input_argc; output<total_argc; ++output ) {
            arg_t *arg = &node->args[output];
            io_cb_t *io = arg->io;
            assert( io->prepare_write != NULL );
            io->prepare_write( arg );
        }
        node->process( node->args );
        for( int output = node->input_argc; output<total_argc; ++output ) {
            arg_t *arg = &node->args[output];
            io_cb_t *io = arg->io;
            assert( io->commit_write != NULL );
            io->commit_write( arg );
        }
        for( int input = 0; input<node->input_argc; ++input ) {
            arg_t *arg = &node->args[input];
            io_cb_t *io = arg->io;
            assert( io->commit_read != NULL );
            io->commit_read( arg );
        }
    }
}

void process_graph( node_t *g[] ) {
    node_t *last_node = NULL;
    for( node_t **n = g; *n != NULL; ++n ) {
        node_t *node = *n;
        process_node( node );
    }
}

static uint8_t fileBuf[128];
file_io_t inputFile = {
    .cb.data = &fileBuf,
    .data_type = INT16,
};

#define RING_BUFFER_SIZE 8
uint8_t ringA_storage[sizeof(buffer_io_t)+RING_BUFFER_SIZE];
buffer_io_t *ringA = (buffer_io_t*)ringA_storage;

uint8_t ringB_storage[sizeof(buffer_io_t)+RING_BUFFER_SIZE];
buffer_io_t *ringB = (buffer_io_t*)ringB_storage;

node_t adderA = {
    .process = simple,
    .input_argc = 1,
    .output_argc = 1,
    .args = {
        { (io_cb_t*)&inputFile, NUM_SAMPLES },
        { (io_cb_t*)ringA_storage, NUM_SAMPLES },
    },
};

node_t adderB = {
    .process = simple,
    .input_argc = 1,
    .output_argc = 1,
    .args = {
        { (io_cb_t*)ringA_storage, NUM_SAMPLES },
        { (io_cb_t*)ringB_storage, NUM_SAMPLES },
    }
};

node_t *graph[] = {
    &adderA,
    &adderB,
    NULL,
};

int main( int argc, char *args[] ) {
    file_io_init( &inputFile, "input.csv" );
    buffer_io_init( ringA, RING_BUFFER_SIZE );
    buffer_io_init( ringB, RING_BUFFER_SIZE );
    process_graph( graph );
    uint16_t* data = (uint16_t*)bipbuf_peek( &ringB->buf, NUM_SAMPLES );
    for( int i=0; i<NUM_SAMPLES; ++i ) {
        printf("%d\n", data[i]);
    }
    return EXIT_SUCCESS;
}