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

#include <sys/statvfs.h>
#include <sys/stat.h>

#include "scheme.h"

#include "../any_log.h"

static void block_fs_update(block_t *block)
{
    const char *path = ((char **)block->state)[0];
    const char *text = ((char **)block->state)[1];

    struct statvfs sbuf;
    assert(statvfs(path, &sbuf) == 0);

    static const char *fs_formats[] = {
        "total",
        "free",
        "used",
        NULL,
    };

    char buffer[32][3] = { 0 };
    snprintf(buffer[0], 32, "%ld", sbuf.f_blocks * sbuf.f_frsize);
    snprintf(buffer[1], 32, "%ld", sbuf.f_bavail * sbuf.f_bsize);
    snprintf(buffer[2], 32, "%ld", (sbuf.f_blocks - sbuf.f_bavail) * sbuf.f_bsize);

    const char *fs_values[] = {
        buffer[0],
        buffer[1],
        buffer[2],
        NULL,
    };

    free(block->text.text);
    block->text.text = strformat(text, '%', fs_formats, fs_values);
    assert(block->text.text != NULL);
}

static void block_fs_finalize(block_t *block)
{
    free(block->state);
}

static bool block_fs_validate(block_t *block, const block_scheme_t *scheme)
{
    if (block->text.text == NULL) {
        log_error("Block '%s' requires key '%s'", block->label, "text");
        return false;
    }

    if (strstr(block->text.text, "%{") == NULL) {
        log_warn("Block '%s' does not use any fs variable", block->label);

        block->update_cb = NULL;
        log_debug("Disabled updates for block '%s'", block->label);
        return true;
    }

    const char *path = ((char **)block->state)[0];
    struct stat sbuf;

    if (path == NULL || stat(path, &sbuf) < 0) {
        log_error("Block '%s' was given an invalid path '%s'", block->label, path);
        return false;
    }

    ((char **)block->state)[1] = block->text.text;
    block->text.text = NULL;

    return true;
}

static const config_entry_t block_fs_entries[] = {
    { "path", CONFIG_STRING, NULL, 0 },
    { 0 },
};

const block_scheme_t block_fs_scheme = {
    .name = "fs",
    .block = {
        .type = BLOCK_TEXT,
        .update_interval = {
            .tv_sec = 20,
            .tv_nsec = 0,
        },
        .update_cb = block_fs_update,
        .finalize_cb = block_fs_finalize,
    },
    .size = 2 * sizeof(char *),
    .entries = block_fs_entries,
    .validate = block_fs_validate,
};