#include "../command.h"

#include <errno.h>
#include <grp.h>
#include <pwd.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>
#include <dirent.h>
#include <ftw.h>
#include <limits.h>

#define FILE_COLOR      "\x1b[0m"
#define DIR_COLOR       "\x1b[1;34m"
#define SET_UID_COLOR   "\x1b[41m"
#define SET_GID_COLOR   "\x1b[43m"
#define EXEC_COLOR      "\x1b[1;92m"
#define LINK_COLOR      "\x1b[1;96m"

struct Flags {
    bool hidden;
    bool hide_dot;
    bool more_info;
    bool one_column;
    bool recurse;
};

static DIR* get_directory(char* path) {
    DIR* d = opendir(path);
    if (d == NULL) {
        printf("\x1b[0merror: failed to open directory '%s': %s\n", path, strerror(errno));
    }
    return d;
}

static void append_path(char buf[PATH_MAX], const char* dir_path, const struct dirent* file) {
    size_t dir_len = strlen(dir_path);
    memcpy(buf, dir_path, dir_len);
    if (buf[dir_len-1] != '/') {
        buf[dir_len] = '/';
        dir_len++;
    }
    memcpy(buf + dir_len, file->d_name, strlen(file->d_name) + 1);
}

static void list_file(struct dirent* file, struct Flags* flags, const char* dir_path) {

    char* color;

    if (file->d_type == DT_DIR) {
        color = DIR_COLOR;
    } else if (file->d_type == DT_LNK) {
        color = LINK_COLOR;
    } else {
        color = FILE_COLOR;
    }

    if (flags->more_info) {

        uid_t uid = getuid();
        gid_t gid = getgid();

        char buf[PATH_MAX];
        append_path(buf, dir_path, file);
        
        struct stat s;
        if (stat(buf, &s) < 0) {
            printf("\x1b[0merror: failed to read file '%s': %s\n", buf, strerror(errno));
            return;
        }

        if (file->d_type == DT_DIR) putchar('d');
        else if (file->d_type == DT_LNK) putchar('l');
        else putchar('-');

        bool group_sticky = false;
        bool user_sticky = false;
        bool exectuable = false;

        putchar((s.st_mode & S_IRUSR) ? 'r' : '-');
        putchar((s.st_mode & S_IWUSR) ? 'w' : '-');
        if (s.st_mode & S_IXUSR) {
            if (putchar(s.st_mode & S_ISUID)) {
                putchar('s');
                user_sticky = true;
            } else {
                putchar('x');
            }
            if (!exectuable) exectuable = s.st_uid == uid;
        } else {
            putchar('-');
        }

        putchar((s.st_mode & S_IRGRP) ? 'r' : '-');
        putchar((s.st_mode & S_IWGRP) ? 'w' : '-');
        if (s.st_mode & S_IXGRP) {
            if (putchar(s.st_mode & S_ISGID)) {
                putchar('s');
                group_sticky = true;
            } else {
                putchar('x');
            }
            if (!exectuable) exectuable = s.st_gid == gid;
        } else {
            putchar('-');
        }

        putchar((s.st_mode & S_IROTH) ? 'r' : '-');
        putchar((s.st_mode & S_IWOTH) ? 'w' : '-');
        if (s.st_mode & S_IXOTH) {
            putchar('x');
            exectuable = true;
        } else {
            putchar('-');
        }

        printf(" %ld\t", s.st_nlink);

        struct passwd* passwd = getpwuid(s.st_uid);
        struct group* group = getgrgid(s.st_gid);

        printf("%s ", passwd->pw_name);
        printf("%s ", group->gr_name);

        print_file_size(s.st_size);
        print_date_time(s.st_mtim.tv_sec + s.st_mtim.tv_nsec / 1000000);

        if (file->d_type == DT_REG) {
            if (user_sticky) {
                color = SET_UID_COLOR;
            } else if (group_sticky) {
                color = SET_GID_COLOR;
            } else if (exectuable) {
                color = EXEC_COLOR;
            }
        }

        printf("%s%s\x1b[0m", color, file->d_name);

        if (file->d_type == DT_LNK) {
            char link[PATH_MAX];
            if (readlink(buf, link, PATH_MAX) < 0) {
                printf("\n");
            } else {
                printf(" -> %s\n", link);
            }
        } else {
            printf("\n");
        }
        
    } else {
        printf("%s%s", color, file->d_name);
        flags->one_column ? putchar('\n') : putchar(' ');
    }
}

static bool is_dot_dir(const char* path) {
    return streql(path, ".") || streql(path, "..");
}

static void recurse_directory(char* path, struct Flags* flags) {
    DIR* d;
    struct dirent* file;
    bool first = true;

    d = get_directory(path);
    if (d == NULL) return;

    while((file = readdir(d)) != NULL) {
        if (file->d_type == DT_DIR) continue;
        if (!flags->hidden && prefix(".", file->d_name)) continue;
        if (is_dot_dir(file->d_name)) continue;
        if (first) {
            printf("\n%s%s:%s\n", DIR_COLOR, path, FILE_COLOR);
            first = false;
        }
        list_file(file, flags, path);
    }

    if (!flags->more_info) printf("\n");

    closedir(d);

    d = get_directory(path);
    if (d == NULL) return;
    
    while((file = readdir(d)) != NULL) {
        if (file->d_type != DT_DIR) continue;
        if (!flags->hidden && prefix(".", file->d_name)) continue;
        if (is_dot_dir(file->d_name)) continue;
        char buf[PATH_MAX];
        append_path(buf, path, file);
        recurse_directory(buf, flags);
    }

    closedir(d);
}

static void list_directory(char* path, struct Flags* flags) {
    if (flags->recurse) {
        recurse_directory(path, flags);
        return;
    }

    DIR* d = get_directory(path);
    if (d == NULL) return;

    struct dirent* file;

    while ((file = readdir(d)) != NULL) {
        if (!flags->hidden && prefix(".", file->d_name)) continue;
        if (flags->hide_dot && is_dot_dir(file->d_name)) continue;
        list_file(file, flags, path);
    }

    closedir(d);
}

static void help() {
    printf("Usage: ls [FILE]...\n\n");
    printf("List directory contents\n\n");
    printf("\t-1\tOne column output\n");
    printf("\t-l\tLong format\n");
    printf("\t-a\tInclude names starting with .\n");
    printf("\t-A\tLike -a but without . and ..\n");
    printf("\t-R\tRecurse\n");
    exit(EXIT_SUCCESS);
}

COMMAND(ls) {

    struct Flags flags;
    flags.hidden = false;
    flags.more_info = false;
    flags.hide_dot = false;
    flags.one_column = false;
    flags.recurse = false;

    int start = 0;
    for (int i = 0; i < argc; i++) {
        if (!prefix("-", argv[i])) break;
        if (streql("--help", argv[i])) help();
        start++;
        for (size_t j = 1; j < strlen(argv[i]); j++) {
            char c = argv[i][j];
            switch (c) {
                case 'R':
                    flags.recurse = true;
                    break;
                case '1':
                    flags.one_column = true;
                    break;
                case 'A':
                    flags.hide_dot = true;
                    flags.hidden = true;
                    break;
                case 'a':
                    flags.hidden = true;
                    break;
                case 'l':
                    flags.more_info = true;
                    break;
                default:
                    error("error: unkown option -%c", c);
            }
        }
    }

    if (argc - start == 0) {
        list_directory(".", &flags);
        if (!flags.more_info) printf("\n");
        return EXIT_SUCCESS;
    }

    bool titled = argc - start > 1;
    for (int i = start; i < argc; i++) {
        if (titled && !flags.recurse) {
            printf("\n%s%s:%s\n", DIR_COLOR, argv[i], FILE_COLOR);
        }
        list_directory(argv[i], &flags);
        if (titled && !flags.recurse) printf("\n");
    }

    if (!flags.more_info) printf("\n");
    return EXIT_SUCCESS;
}