module auth.dao;

import handy_httpd.components.optional;
import auth.model;

interface UserRepository {
    Optional!User findByUsername(string username);
    User createUser(string username, string passwordHash);
    void deleteByUsername(string username);
}

/**
 * User implementation that stores each user's data in a separate directory.
 */
class FileSystemUserRepository : UserRepository {
    import std.path;
    import std.file;
    import std.json;

    private string usersDir;

    this(string usersDir = "users") {
        this.usersDir = usersDir;
    }

    Optional!User findByUsername(string username) {
        if (
            !validateUsername(username) ||
            !exists(getUserDir(username)) ||
            !exists(getUserDataFile(username))
        ) {
            return Optional!User.empty;
        }
        JSONValue userObj = parseJSON(readText(getUserDataFile(username)));
        return Optional!User.of(User(
            username,
            userObj.object["passwordHash"].str
        ));
    }

    User createUser(string username, string passwordHash) {
        if (!validateUsername(username)) throw new Exception("Invalid username");
        if (exists(getUserDir(username))) throw new Exception("User already exists.");
        JSONValue userObj = JSONValue.emptyObject;
        userObj.object["passwordHash"] = JSONValue(passwordHash);
        string jsonStr = userObj.toPrettyString();
        if (!exists(this.usersDir)) mkdir(this.usersDir);
        mkdir(getUserDir(username));
        std.file.write(getUserDataFile(username), cast(ubyte[]) jsonStr);
        return User(username, passwordHash);
    }

    void deleteByUsername(string username) {
        if (validateUsername(username) && exists(getUserDir(username))) {
            rmdirRecurse(getUserDir(username));
        }
    }

    private string getUserDir(string username) {
        return buildPath(this.usersDir, username);
    }

    private string getUserDataFile(string username) {
        return buildPath(this.usersDir, username, "user-data.json");
    }
}