/*
 * Copyright (c) 2026, Chloe Moffett
 * Provided under the BSD-3 clause
 */

#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <unistd.h>
#include <dirent.h>
#include "libremail/file.h"
#include "libremail/common.h"

/* Maximum command components */
#define CMD_MAX_CNP 6

/* Mailutil version */
#define MAILUTIL_VERSION "0.0.1"

/*
 * Macro used to assert that the command list count is not
 * zero to avoid code duplication.
 */
#define ASSERT_COUNT(CNT)                           \
    if ((CNT) == 0) {                               \
        printf("error: cmdlist count is zero\n");   \
        return -1;                                  \
    }

/*
 * Macro used to ensure that overflows don't happen
 */
#define ASSERT_COUNT_N(CNT, MAX)                            \
    if ((CNT) < (MAX)) {                                    \
        printf("error: too few parameters for command\n");  \
        return -1;                                          \
    }

static void
help(void)
{
    printf("usage: ./mailutil [... flags] [verb] [...]\n");
    printf("... [-h] Display this help menu\n");
    printf("... [-v] Display the version\n");
}

static void
version(void)
{
    printf("Version v%s\n", MAILUTIL_VERSION);
}

static int
cmd_mailbox_list(void)
{
    DIR *dir;
    struct dirent *dirent;

    if ((dir = opendir(MAILBOX_PREFIX)) == NULL) {
        perror("opendir");
        return -1;
    }

    while ((dirent = readdir(dir)) != NULL) {
        if (dirent->d_name[0] == '.') {
            continue;
        }

        printf("[mailbox] :: %s\n", dirent->d_name);
    }

    closedir(dir);
    return 0;
}

/*
 * Parse a "mailbox rm" command
 *
 * @cmdlist: Command list to parse
 * @count:   Number of entries inside command list
 *
 * Returns zero on success
 */
static int
cmd_mailbox_rm(const char *cmdlist[CMD_MAX_CNP], size_t count)
{
    char pathbuf[64];

    ASSERT_COUNT_N(count, 3);

    snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
        MAILBOX_PREFIX, cmdlist[2]);

    /* Destroy the mailbox */
    if (rmdir(pathbuf) < 0) {
        perror("rmdir");
        return -1;
    }

    printf("deleted mailbox '%s'\n", cmdlist[2]);
    return 0;
}

/*
 * Parse a "mailbox create" command
 *
 * @cmdlist: Command list to parse
 * @count:   Number of entries inside command list
 *
 * Returns zero on success
 */
static int
cmd_mailbox_create(const char *cmdlist[CMD_MAX_CNP], size_t count)
{
    char pathbuf[64];

    ASSERT_COUNT_N(count, 3);

    snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
        MAILBOX_PREFIX, cmdlist[2]);

    /* Create the mailbox */
    if (try_mkdir(pathbuf, DEFAULT_MAILBOX_MODE) < 0) {
        printf("fatal: failed to create mailbox\n");
        perror("try_mkdir");
        return -1;
    }

    printf("created mailbox '%s' @ %s\n", cmdlist[2], pathbuf);
    return 0;
}

/*
 * Parse a "mailbox" command
 *
 * @cmdlist: Command list to parse
 * @count:   Number of entries inside command list
 *
 * Returns zero on success
 */
static int
cmd_mailbox(const char *cmdlist[CMD_MAX_CNP], size_t count)
{
    ASSERT_COUNT_N(count, 2);

    if (strcmp(cmdlist[1], "create") == 0) {
        return cmd_mailbox_create(cmdlist, count);
    }

    if (strcmp(cmdlist[1], "list") == 0) {
        return cmd_mailbox_list();
    }

    if (strcmp(cmdlist[1], "rm") == 0) {
        return cmd_mailbox_rm(cmdlist, count);
    }

    printf("error: bad parameter\n");
    return -1;
}

/*
 * Parse a command given from the command line
 *
 * @cmdlist: Command list to parse
 * @count:   Number of entries inside command list
 *
 * Returns zero on success
 */
static int
parse_cmd(const char *cmdlist[CMD_MAX_CNP], size_t count)
{
    ASSERT_COUNT(count);

    if (strcmp(cmdlist[0], "mailbox") == 0) {
        return cmd_mailbox(cmdlist, count);
    }

    printf("error: bad parameter\n");
    return -1;
}

int
main(int argc, char **argv)
{
    int opt;
    const char *cmdlist[CMD_MAX_CNP];
    size_t cmdlist_i = 0;

    if (argc < 2) {
        printf("fatal: too few arguments\n");
        help();
        return -1;
    }

    while ((opt = getopt(argc, argv, "hv")) != -1) {
        switch (opt) {
        case 'h':
            help();
            return -1;
        case 'v':
            version();
            return 0;
        }
    }

    /* Accumulate command line parameters */
    while (optind < argc) {
        cmdlist[cmdlist_i++] = argv[optind++];
    }

    if (parse_cmd(cmdlist, cmdlist_i) < 0) {
        printf("fatal: error parsing command list\n");
        return -1;
    }

    return 0;
}