#include "../../include/std/file.h"
#include "../../include/std/mem.h"
#include "../../include/std/log.h"
#include "../../include/std/alloc.h"
#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <string.h>
#include <limits.h>
#include <stdlib.h>

#include <dirent.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <unistd.h>

#define SCANDIR_PATH_LENGTH 4096
#define MAX_FILE_SIZE 1024*1024*48 /* 48 mb */
#if 0

static int scan_dir_recursive_internal(char *dir_path, int path_length, scan_dir_callback_func callback_func, void *userdata) {
    DIR *dir;
    struct dirent *entry;
    struct stat file_stats;
    int filename_length;
    int path_length_start;

    path_length_start = path_length;
    if((dir = opendir(dir_path)) == NULL) {
        int error;
        error = errno;
        amal_log_perror("scan_dir_recursive");
        return error;
    }

    while((entry = readdir(dir)) != NULL) {
        /*
        Skip hidden files. Name will always at least include null terminator
        so it's ok to not check filename length. And file names are never empty, right???
        */
        if(entry->d_name[0] == '.')
            continue;

        /* Reset path concat, because it's overwritten by recursive call to scan dir */
        path_length = path_length_start;
        filename_length = strlen(entry->d_name);
        /* current path '/' filename '\0' */
        if(path_length + 1 + filename_length + 1 > SCANDIR_PATH_LENGTH) {
            amal_log_error("Filepath too long. Trying to append %s to %s", entry->d_name, dir_path);
            return -1;
        }

        /* Replace '\0' with '/' */
        dir_path[path_length] = '/';
        ++path_length;
        am_memcpy(&dir_path[path_length], entry->d_name, filename_length);
        path_length += filename_length;
        dir_path[path_length] = '\0';
        
        if(stat(dir_path, &file_stats) == -1) {
            amal_log_perror("scan_dir_recursive_internal");
            goto cleanup;
        }

        if(S_ISDIR(file_stats.st_mode)) {
            cleanup_if_error(scan_dir_recursive_internal(dir_path, path_length, callback_func, userdata));
        } else if(S_ISREG(file_stats.st_mode)) {
            if(!callback_func(dir_path, path_length, userdata))
                goto cleanup_noerr;
        } else if(S_ISLNK(file_stats.st_mode)) {
            amal_log_warning("Symlink ignored: %s", entry->d_name);
        } else {
            /* Ignore block devices and all other types of files */
        }
    }

    cleanup_noerr:
    closedir(dir);
    return 0;

    cleanup:
    closedir(dir);
    return -1;
}

int scan_dir_recursive(const char *dir_path, scan_dir_callback_func callback_func, void *userdata) {
    char scandir_path[SCANDIR_PATH_LENGTH];
    int dir_path_length = strlen(dir_path) + 1; /* include null terminator */
    am_memcpy(scandir_path, dir_path, dir_path_length);
    return scan_dir_recursive_internal(scandir_path, dir_path_length - 1, callback_func, userdata);
}

static int mapped_file_mode_to_system_file_mode(MappedFileMode file_mode) {
    switch(file_mode) {
        case MAPPED_FILE_READ:          return PROT_READ;
        case MAPPED_FILE_WRITE:         return PROT_WRITE;
        case MAPPED_FILE_READ_WRITE:    return PROT_READ | PROT_WRITE;
        default:
            assert(bool_false);
            return PROT_READ;
    }
}

static int mapped_file_mode_to_open_mode(MappedFileMode file_mode) {
    switch(file_mode) {
        case MAPPED_FILE_READ:          return O_RDONLY;
        case MAPPED_FILE_WRITE:         return O_WRONLY;
        case MAPPED_FILE_READ_WRITE:    return O_RDWR;
        default:
            assert(bool_false);
            return O_RDONLY;
    }
}

int mapped_file_init(MappedFile *self, const char *filepath, MappedFileMode file_mode) {
    struct stat file_stats;
    int fd;
    const char *memblock;
    int map_file_system_mode;

    self->file_data = NULL;
    self->file_size = 0;
    self->fd = -1;

    fd = open(filepath, mapped_file_mode_to_open_mode(file_mode));
    if(fd == -1) return errno;
    if(fstat(fd, &file_stats) == -1) {
        amal_log_perror(filepath);
        goto cleanup;
    }

    map_file_system_mode = mapped_file_mode_to_system_file_mode(file_mode);
    memblock = mmap(NULL, file_stats.st_size, map_file_system_mode, MAP_SHARED, fd, 0);
    if(memblock == MAP_FAILED) {
        amal_log_perror(filepath);
        goto cleanup;
    }

    self->file_data = memblock;
    self->file_size = file_stats.st_size;
    self->fd = fd;
    return 0;

    cleanup:
    close(fd);
    return -1;
}

int mapped_file_deinit(MappedFile *self) {
    int result_munmap;
    int result_close;

    if(!self->file_data)
        return 0;
    
    result_munmap = munmap((void*)self->file_data, self->file_size);
    if(result_munmap == -1)
        amal_log_perror("mapped_file_deinit");
    result_close = close(self->fd);
    if(result_close == -1)
        amal_log_perror("mapped_file_deinit");
    self->file_data = NULL;
    self->file_size = 0;
    self->fd = 0;
    if(result_munmap == -1 || result_close == -1)
        return -1;
    else
        return 0;
}
#endif

int read_whole_file(const char *filepath, Buffer *data_result) {
    FILE *file;
    int result;
    usize bytes_read;
    long size;

    file = fopen(filepath, "rb");
    if(!file) {
        int error = errno;
        amal_log_error("read_whole_file: %s failed, error: %s", filepath, strerror(error));
        return error;
    }

    result = fseek(file, 0, SEEK_END);
    if(result != 0) {
        result = ferror(file);
        goto cleanup;
    }
    
    size = ftell(file);
    if(size == -1) {
        int error = errno;
        result = error;
        amal_log_error("read_whole_file: %s failed, error: %s", filepath, strerror(error));
        goto cleanup;
    }

    result = fseek(file, 0, SEEK_SET);
    if(result != 0) {
        result = -1;
        goto cleanup;
    }

    if(size > MAX_FILE_SIZE) {
        amal_log_error("File %s is too large (larger than 48 megabytes)", filepath);
        result = -1;
        goto cleanup;
    }

    assert(data_result->capacity == 0 && data_result->size == 0);
    cleanup_if_error(buffer_append_empty(data_result, size));
    bytes_read = fread(data_result->data, 1, data_result->size, file);
    if(bytes_read != (unsigned long)size)
        result = -1;

    cleanup:
    fclose(file);
    return result;
}

int file_get_canonical_path(const char *filepath, char **result_path, usize *result_path_size) {
    char result_path_tmp[PATH_MAX];
    if(!realpath(filepath, result_path_tmp)) {
        int ret;
        ret = errno;
        amal_log_error("file_get_canonical_path: realpath failed for path %s, error: %s", filepath, strerror(ret));
        return ret;
    }
    *result_path_size = strnlen(result_path_tmp, PATH_MAX);
    return_if_error(am_malloc(*result_path_size + 1, (void**)result_path));
    am_memcpy(*result_path, result_path_tmp, *result_path_size);
    (*result_path)[*result_path_size] = '\0';
    return 0;
}

BufferView file_get_parent_directory(BufferView filepath) {
    int i;
    for(i = filepath.size - 1; i >= 0; --i) {
        if(filepath.data[i] == '/')
            return create_buffer_view(filepath.data, i);
    }
    return create_buffer_view(".", 1);
}

BufferView file_get_name(BufferView filepath) {
    int i;
    for(i = filepath.size - 1; i >= 0; --i) {
        if(filepath.data[i] == '/')
            return create_buffer_view(filepath.data + i, filepath.size - i);
    }
    return filepath;
}