#define AL_LOG_SECTION "file"
#include <al/log.h>
#include <sys/mman.h>

#include "../error.h"

#include "file.h"

static bool lock_file_internal(s32 fd, size_t size)
{
    struct flock l = { .l_type = F_WRLCK, .l_whence = SEEK_SET, .l_start = 0, .l_len = size };
    if (fcntl(fd, F_SETLKW, &l) == -1) {
        log_error("fcntl(F_SETLKW, F_WRLCK) failed (%s).", nn_strerror(errno));
        close(fd);
        return false;
    }
    return true;
}

static bool unlock_file_internal(s32 fd, size_t size)
{
    struct flock l = { .l_type = F_ULOCK, .l_whence = SEEK_SET, .l_start = 0, .l_len = size };
    if (fcntl(fd, F_SETLKW, &l) == -1) {
        log_error("fcntl(F_SETLKW, F_ULOCK) failed (%s).", nn_strerror(errno));
        return false;
    }
    return true;
}

static bool open_file_linux(s32 *fd, str *path, s32 flags)
{
    char *c_str = al_str_to_c_str(path);
    bool success = (*fd = open(c_str, flags, 0644)) != -1;
    al_free(c_str);
    return success;
}

bool nn_file_open(struct nn_file *file, str *path, s32 flags)
{
    file->flags = flags;
    s32 oflags = (flags & NNWT_FILE_READONLY) ? O_RDONLY : O_RDWR;
    if (flags & NNWT_FILE_CREATE) {
        oflags |= O_CREAT;
    }

    if (!open_file_linux(&file->fd, path, oflags)) {
        log_error("open(%.*s) failed (%d: %s).", al_str_x(path), errno, nn_strerror(errno));
        return false;
    }

    struct stat sb;
    s32 res = fstat(file->fd, &sb);
    if (res == -1) {
        log_error("fstat() failed (%s).", nn_strerror(errno));
        close(file->fd);
        return false;
    }
    file->size = sb.st_size;

    if (flags & NNWT_FILE_LOCK && !lock_file_internal(file->fd, file->size)) {
        close(file->fd);
        return false;
    }

    al_str_clone(&file->path, path);

    return true;
}

bool nn_file_exists(str *path)
{
    char *c_str = al_str_to_c_str(path);
    s32 ret = access(c_str, F_OK);
    al_free(c_str);
    return ret == 0;
}

bool nn_file_create(str *path)
{
    s32 fd;
    bool opened = open_file_linux(&fd, path, O_RDWR | O_CREAT);
    if (opened) close(fd);
    return opened;
}

off_t nn_file_seek(struct nn_file *file, off_t offset, s32 whence)
{
    off_t res = lseek(file->fd, offset, whence);
    if (res == (off_t)-1) {
        log_error("lseek(%zd, %d) failed (%s).", offset, whence, nn_strerror(errno));
    }
    return res;
}

bool nn_file_truncate(struct nn_file *file, off_t size)
{
    s32 ret = ftruncate(file->fd, size);
    if (ret != 0) {
        log_error("ftruncate(%zd) failed (%s).", size, nn_strerror(errno));
        return false;
    }
    file->size = size;
    return true;
}

bool nn_file_flush(struct nn_file *file)
{
    s32 ret = fsync(file->fd);
    if (ret != 0) {
        log_error("fsync() failed (%s).", nn_strerror(errno));
        return false;
    }
    return true;
}

#define file_io_loop(call, fail_case) \
    size_t bc = 0; \
    ssize_t res; \
    for (;;) { \
        res = call(file->fd, buf, size - bc); \
        if (fail_case) { \
            log_error(""#call"() failed (%s).", nn_strerror(errno)); \
            return false; \
        } \
        if ((bc += res) >= size) break; \
    } \
    return true

bool nn_file_write(struct nn_file *file, void *buf, size_t size)
{
    file_io_loop(write, (res == -1));
}

bool nn_file_read(struct nn_file *file, void *buf, size_t size)
{
    file_io_loop(read, (res == -1));
}

void *nn_file_mmap(struct nn_file *file)
{
    if (file->size == 0) return NULL;
    s32 flags = PROT_READ | ((file->flags & NNWT_FILE_READONLY) ? 0 : PROT_WRITE);
    void *map = mmap(NULL, file->size, flags, MAP_SHARED, file->fd, 0L);
    if (map == MAP_FAILED) {
        log_error("mmap(%.*s) failed (%s).", al_str_x(&file->path), nn_strerror(errno));
        return NULL;
    }
    return map;
}

void *nn_file_mremap(struct nn_file *file, size_t size, void *old_map)
{
    void *map = mremap(old_map, file->size, size, MREMAP_MAYMOVE);
    if (map == MAP_FAILED) {
        log_error("mremap(%p, %zu, %zu) failed (%s).", old_map, file->size, size, nn_strerror(errno));
        return NULL;
    }
    return map;
}

void nn_file_munmap(struct nn_file *file, void *map)
{
    s32 ret = munmap(map, file->size);
    if (ret != 0) {
        log_error("munmap(%p, %zu) failed (%s).", map, file->size, nn_strerror(errno));
    }
}

void nn_file_close(struct nn_file *file)
{
    if (file->flags & NNWT_FILE_LOCK) {
        unlock_file_internal(file->fd, file->size);
    }
    close(file->fd);
    al_str_free(&file->path);
}

bool nn_dir_open(struct nn_dir *dir, str *path)
{
    char *c_str = al_str_to_c_str(path);
    dir->dir = opendir(c_str);
    al_free(c_str);
    if (!dir->dir) {
        log_error("opendir(%.*s) failed (%s).", al_str_x(path), nn_strerror(errno));
        return false;
    }
    al_str_clone(&dir->path, path);
    return true;
}

void nn_dir_close(struct nn_dir *dir)
{
    closedir(dir->dir);
    al_str_free(&dir->path);
}

bool nn_dir_exists(str *path)
{
    DIR *dir;
    char *c_str = al_str_to_c_str(path);
    dir = opendir(c_str);
    al_free(c_str);
    if (!dir) {
        if (errno != ENOENT) {
            log_error("opendir(%.*s) failed (%s).", al_str_x(path), nn_strerror(errno));
        }
        return false;
    }
    closedir(dir);
    return true;
}

bool nn_dir_create(str *path)
{
    char *c_str = al_str_to_c_str(path);
    s32 ret = mkdir(c_str, 0755);
    al_free(c_str);
    if (ret == -1) {
        log_error("mkdir(%.*s) failed (%s).", al_str_x(path), nn_strerror(errno));
        return false;
    }
    return true;
}

bool nn_dir_read(struct nn_dir *dir, struct nn_dir_entry *entry)
{
    errno = 0;
    if (!(entry->entry = readdir(dir->dir))) {
        if (errno) {
            log_error("readdir(%.*s) failed (%s).", al_str_x(&dir->path), nn_strerror(errno));
        }
        return false;
    }

    switch (entry->entry->d_type) {
    case DT_UNKNOWN:
        entry->type = NNWT_ENTRY_FILE;
        break;
    case DT_REG:
    case DT_DIR:
        entry->type = NNWT_ENTRY_DIR;
        break;
    default:
        entry->type = NNWT_ENTRY_OTHER;
        break;
    }

    return true;
}

void nn_dir_entry_get_name(struct nn_dir_entry *entry, str *name)
{
    al_str_clone(name, &al_str_cr(entry->entry->d_name));
}

const char *nn_dir_entry_get_os_name(struct nn_dir_entry *entry)
{
    return entry->entry->d_name;
}

void nn_dir_entry_get_path(struct nn_dir_entry *entry, struct nn_dir *dir, str *path)
{
    al_str_clone(path, &dir->path);
    al_str_cat(path, &al_str_c("/"));
    al_str_cat(path, &al_str_cr(entry->entry->d_name));
}