/*                 _,.---._    .-._        .--.-. ,--.--------.
 *   _,..---._   ,-.' , -  `. /==/ \  .-._/==/  //==/,  -   , -\
 * /==/,   -  \ /==/_,  ,  - \|==|, \/ /, |==\ -\\==\.-.  - ,-./
 * |==|   _   _\==|   .=.     |==|-  \|  | \==\- \`--`\==\- \
 * |==|  .=.   |==|_ : ;=:  - |==| ,  | -|  `--`-'     \==\_ \
 * |==|,|   | -|==| , '='     |==| -   _ |             |==|- |
 * |==|  '='   /\==\ -    ,_ /|==|  /\ , |             |==|, |
 * |==|-,   _`/  '.='. -   .' /==/, | |- |             /==/ -/
 * `-.`.____.'     `--`--''   `--`./  `--`             `--`--`
 *                    _ __    ,---.      .-._         .=-.-.  _,.----.
 *                 .-`.' ,`..--.'  \    /==/ \  .-._ /==/_ /.' .' -   \
 *                /==/, -   \==\-/\ \   |==|, \/ /, /==|, |/==/  ,  ,-'
 *               |==| _ .=. /==/-|_\ |  |==|-  \|  ||==|  ||==|-   |  .
 *               |==| , '=',\==\,   - \ |==| ,  | -||==|- ||==|_   `-' \
 *               |==|-  '..'/==/ -   ,| |==| -   _ ||==| ,||==|   _  , |
 *               |==|,  |  /==/-  /\ - \|==|  /\ , ||==|- |\==\.       /
 *               /==/ - |  \==\ _.\=\.-'/==/, | |- |/==/. / `-.`.___.-'
 *               `--`---'   `--`        `--`./  `--``--`-`
 *
 *	@(#)Copyright (c) 2023, Nathan D. Fisher.
 *
 *      This is free software.  It comes with NO WARRANTY.
 *      Permission to use, modify and distribute this source code
 *      is granted subject to the following conditions.
 *      1/ that the above copyright notice and this notice
 *      are preserved in all copies and that due credit be given
 *      to the author.
 *      2/ that any changes to this code are clearly commented
 *      as such so that the author does not get blamed for bugs
 *      other than his own.
 */

#if defined (__FreeBSD__) || defined (__DragonFly__)
#include <sys/types.h>
#include <sha.h>
#include <sha256.h>
#elif defined (__NetBSD__) || defined (__OpenBSD__)
#include <sys/types.h>
#include <sha1.h>
#include <sha2.h>
#elif defined (__linux__)
#include <sha1.h>
#include <sha2.h>
#endif /* if defined (__FreeBSD__) */

#include <md5.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>

#include "bytes.h"
#include "haggis.h"

static unsigned char header[7] = {0x89, 'h', 'a', 'g', 'g', 'i', 's'};

int haggis_store_header(FILE *stream) {
    if (fwrite(header, 1, 7, stream) < 7)
        return 1;
    return 0;
}

int haggis_check_header(FILE *stream) {
    unsigned char *buf[7];
    if (fread(buf, 1, 7, stream) < 7)
        return 1;
    if (memcmp(buf, header, 7))
        return 2;
    return 1;
}

int haggis_store_device(FILE *stream, struct haggis_device *dev) {
    if (fwrite(dev->major.bytes, 1, 4, stream) != 4)
        return 1;
    if (fwrite(dev->minor.bytes, 1, 4, stream) != 4)
        return 1;
    return 0;
}

int haggis_load_device(FILE *stream, struct haggis_device *dev) {
    if (fread(dev->major.bytes, 1, 4, stream) != 4)
        return 1;
    if (fread(dev->minor.bytes, 1, 4, stream) != 4)
        return 1;
    return 0;
}

int haggis_store_cksum(FILE *stream, struct haggis_checksum *cksum) {
    char flag;
    switch (cksum->tag) {
    case md5:
        flag = 0;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        if (fwrite(cksum->sum->md5, 1, 16, stream) != 16)
            return 1;
        break;
    case sha1:
        flag = 1;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        if (fwrite(cksum->sum->sha1, 1, 20, stream) != 20)
            return 1;
        break;
    case sha256:
        flag = 2;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        if (fwrite(cksum->sum->sha256, 1, 32, stream) != 32)
            return 1;
        break;
    case skip:
        flag = 3;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        break;
    }
    return 0;
}

int haggis_load_cksum(FILE *stream, struct haggis_checksum *cksum) {
    char flag;
    if (fread(&flag, 1, 1, stream) != 1)
        return 1;
    switch (flag) {
    case md5:
        cksum->tag = 0;
        if (fread(&cksum->sum->md5, 1, 16, stream) != 16)
            return 1;
        break;
    case sha1:
        cksum->tag = 1;
        if (fread(&cksum->sum->sha1, 1, 20, stream) != 20)
            return 1;
        break;
    case sha256:
        cksum->tag = 2;
        if (fread(&cksum->sum->sha256, 1, 32, stream) != 32)
            return 1;
        break;
    case skip:
        cksum->tag = 3;
        break;
    }
    return 0;
}

int validate_md5(struct haggis_file *file) {
    MD5_CTX ctx;
    u8 digest[MD5_DIGEST_LENGTH];
    MD5Init(&ctx);
    MD5Update(&ctx, *file->data, (size_t)file->len.val);
    MD5Final(digest, &ctx);
    if (memcmp(file->cksum->sum->md5, digest, sizeof(digest)))
        return 2;
    return 0;
}

#if defined (__FreeBSD__) || defined (__DragonFly__)
int validate_sha1(struct haggis_file *file) {
    SHA1_CTX ctx;
    u8 digest[20];
    SHA1_Init(&ctx);
    SHA1_Update(&ctx, *file->data, (size_t)file->len.val);
    SHA1_Final(digest, &ctx);
    if (memcmp(file->cksum->sum->sha1, digest, sizeof(digest)))
        return 2;
    return 0;
}
#elif defined (__linux__) || defined (__NetBSD__) || defined (__OpenBSD__)
int validate_sha1(struct haggis_file *file) {
    SHA1_CTX ctx;
    u8 digest[20];
    SHA1Init(&ctx);
    SHA1Update(&ctx, *file->data, (size_t)file->len.val);
    SHA1Final(digest, &ctx);
    if (memcmp(file->cksum->sum->sha1, digest, sizeof(digest)))
        return 2;
    return 0;
}
#endif /* if defined (__FreeBSD__) */

#if defined (__FreeBSD__) || defined (__DragonFly) || defined (__NetBSD__)
int validate_sha256(struct haggis_file *file) {
    SHA256_CTX ctx;
    u8 digest[SHA256_DIGEST_LENGTH];
    SHA256_Init(&ctx);
    SHA256_Update(&ctx, *file->data, (size_t)file->len.val);
    SHA256_Final(digest, &ctx);
    if (memcmp(file->cksum->sum->sha256, digest, sizeof(digest)))
        return 2;
    return 0;
}
#elif defined (__linux__) || defined (__OpenBSD__)
int validate_sha256(struct haggis_file *file) {
    SHA2_CTX ctx;
    u8 digest[SHA256_DIGEST_LENGTH];
    SHA256Init(&ctx);
    SHA256Update(&ctx, *file->data, (size_t)file->len.val);
    SHA256Final(digest, &ctx);
    if (memcmp(file->cksum->sum->sha256, digest, sizeof(digest)))
        return 2;
    return 0;
}
#endif /* if defined (__FreeBSD__) */

int haggis_validate_cksum(struct haggis_file *file) {
    switch (file->cksum->tag) {
    case md5:
	return validate_md5(file);
    case sha1:
	return validate_sha1(file);
    case sha256:
	return validate_sha256(file);
    case skip:
        return 0;
    }
    return 0;
}

int haggis_store_file(FILE *stream, struct haggis_file *file) {
    if (store_u64(stream, file->len) != 8)
        return 1;
    if (haggis_store_cksum(stream, file->cksum) != 0)
        return 1;
    int res = fwrite(file->data, 1, (size_t)file->len.val, stream);
    if (res != (size_t)file->len.val)
        return 1;
    return 0;
}

int haggis_load_file(FILE *stream, struct haggis_file *file) {
    if (load_u64(stream, file->len) != 8)
        return 1;
    if (haggis_load_cksum(stream, file->cksum) != 0)
        return 1;
    int res = fread(file->data, 1, (size_t)file->len.val, stream);
    if (res != (size_t)file->len.val)
        return 1;
    return haggis_validate_cksum(file);
}

int haggis_store_filetype(FILE *stream, struct haggis_filetype *filetype) {
    size_t len;
    u8 flag;
    int res;

    switch (filetype->tag) {
    case normal:
        flag = 0;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        if (haggis_store_file(stream, filetype->f_type->file) != 0)
            return 1;
        break;
    case hardlink:
        flag = 1;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        len = (size_t)filetype->f_type->target->len.val;
        res = fwrite(filetype->f_type->target->name, 1, len, stream);
        if (res != (size_t)len)
            return 1;
        break;
    case softlink:
        flag = 2;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        len = (size_t)filetype->f_type->target->len.val;
        res = fwrite(filetype->f_type->target->name, 1, len, stream);
        if (res != (size_t)len)
            return 1;
        break;
    case directory:
        flag = 3;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        break;
    case character:
        flag = 4;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        if (haggis_store_device(stream, filetype->f_type->dev) != 0)
            return 1;
        break;
    case block:
        flag = 5;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        if (haggis_store_device(stream, filetype->f_type->dev) != 0)
            return 1;
        break;
    case fifo:
        flag = 6;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        break;
    case eof:
        flag = 7;
        if (fwrite(&flag, 1, 1, stream) != 1)
            return 1;
        break;
    };
    return 0;
}

int haggis_load_filetype(FILE *stream, struct haggis_filetype *filetype) {
    // todo
    return 0;
}

int haggis_store_node(FILE *stream, struct haggis_node *node) {
    // todo
    return 0;
}

int haggis_load_node(FILE *stream, struct haggis_node *node) {
    // todo
    return 0;
}