#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <hexagram/pcapng.h>

ssize_t hexagram_pcapng_read_options(hexagram_pcapng_stream *stream,
                                     hexagram_pcapng_option_handler *handler,
                                     uint32_t type,
                                     size_t len,
                                     void *data) {
    hexagram_pcapng_option option;
    ssize_t total = 0;

    if (handler == NULL) {
        goto error_no_handler;
    }

    while (total < len) {
        ssize_t readlen;
         size_t remaining;

        if ((readlen = read(stream->fd, &option, sizeof(option))) < 0) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_IO;

            goto error_io;
        } else {
            total += readlen;
        }

        if ((readlen = handler(stream, type, option.code, option.length, data)) < 0) {
            goto error_io;
        } else if (readlen < option.length) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_TRUNCATED;

            goto error_io;
        } else {
            total += readlen;
        }

        if ((remaining = option.length % sizeof(uint32_t)) > 0) {
            size_t padding = sizeof(uint32_t) - remaining;

            if ((readlen = lseek(stream->fd, padding, SEEK_CUR)) < 0) {
                goto error_io;
            } else {
                total += padding;
            }
        }
    }

    stream->error = HEXAGRAM_PCAPNG_ERROR_OK;

    return total;

error_io:
error_no_handler:
    return -1;
}

hexagram_pcapng_stream *hexagram_pcapng_stream_open_fd(int fd) {
    hexagram_pcapng_stream *stream;

    if ((stream = malloc(sizeof(*stream))) == NULL) {
        goto error_malloc_stream;
    }

    stream->fd         = fd;
    stream->error      = HEXAGRAM_PCAPNG_ERROR_OK;
    stream->if_tsresol = 0;

    return stream;

error_malloc_stream:
    return NULL;
}

void hexagram_pcapng_stream_destroy(hexagram_pcapng_stream *stream) {
    memset(stream, '\0', sizeof(*stream));

    free(stream);
}

ssize_t hexagram_pcapng_stream_read(hexagram_pcapng_stream *stream,
                                    hexagram_pcapng_block_handler *handler,
                                    void *data) {
    hexagram_pcapng_block_header header;
    hexagram_pcapng_block_footer footer;
    ssize_t total = 0;

    if (handler == NULL) {
        goto error_no_handler;
    }

    while (1) {
        size_t expected;
        ssize_t readlen;

        if ((readlen = read(stream->fd, &header, sizeof(header))) < 0) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_IO;

            goto error_io;
        } else if (readlen == 0) {
            goto done;
        } else if (readlen < sizeof(header)) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_TRUNCATED;

            goto error_io;
        } else {
            total += readlen;
        }

        expected = header.length - sizeof(header) - sizeof(footer);

        if ((readlen = handler(stream, header.type, expected, data)) < 0) {
            goto error_io;
        } else {
            total += readlen;
        }

        if ((readlen = read(stream->fd, &footer, sizeof(footer))) < 0) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_IO;

            goto error_io;
        } else if (readlen == 0) {
            goto done;
        } else if (readlen < sizeof(footer)) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_TRUNCATED;

            goto error_io;
        } else if (footer.length != header.length) {
            stream->error = HEXAGRAM_PCAPNG_ERROR_FORMAT;

            goto error_io;
        } else {
            total += readlen;
        }
    }

done:
    stream->error = HEXAGRAM_PCAPNG_ERROR_OK;

    return total;

error_io:
error_no_handler:
    return -1;
}