[CCode (cname = "sqlite3_randomness")]
public extern void randomness (int N, void *P);

[GtkTemplate (ui = "/eu/callcc/Wavelet/setup.ui")]
public class Wavelet.Setup : Adw.PreferencesDialog {
    public string status { get; private set; default = _("Not connected"); }

    public bool authn_can_edit { get; private set; default = true; }
    public bool authn_can_validate { get; private set; default = false; }

    public string server_url { get; set; default = ""; }
    public string username { get; set; default = ""; }
    public string password { get; set; default = ""; }
    public string token;
    public string salt;

    public signal void connected (Wavelet.Subsonic api);

    private Sqlite.Database db;
    private Sqlite.Statement db_get;
    private Sqlite.Statement db_set;

    construct {
        var app_config_dir = Path.build_filename (Environment.get_user_config_dir (), "wavelet");

        try {
            File.new_build_filename (app_config_dir).make_directory_with_parents ();
        } catch (Error e) {
            // just ignore if the directory already existed
        }

        int ec = Sqlite.Database.open (Path.build_filename (app_config_dir, "config.db"), out this.db);
        assert (ec == Sqlite.OK);

        ec = this.db.exec ("""
            CREATE TABLE IF NOT EXISTS Setup (key UNIQUE, value);
        """, null, null);
        assert (ec == Sqlite.OK);

        ec = this.db.prepare_v2 ("""SELECT value FROM Setup WHERE key IS ?1""", -1, out this.db_get);
        assert (ec == Sqlite.OK);

        ec = this.db.prepare_v2 ("""INSERT OR REPLACE INTO Setup VALUES (?1, ?2)""", -1, out this.db_set);
        assert (ec == Sqlite.OK);
    }

    [GtkCallback] private void on_authn_changed () {
        this.authn_can_validate = true;
    }

    [GtkCallback] private void on_authn_validate_activated () {
        this.authn_can_validate = false;
        this.authn_can_edit = false;
        this.status = _("Connecting...");

        string new_token, new_salt;
        if (this.password != "") {
            this.salt_password (this.password, out new_token, out new_salt);
        } else {
            new_token = this.token;
            new_salt = this.salt;
        }
        var api = new Wavelet.Subsonic.with_token (
            this.server_url,
            this.username,
            new_token,
            new_salt);

        api.ping.begin ((obj, res) => {
            try {
                api.ping.end (res);
                this.status = _("Connected");
                this.token = new_token;
                this.salt = new_salt;
                this.save ();

                this.connected (api);
            } catch (Error e) {
                this.status = @"$(_("Ping failed")): $(e.message)";
                this.authn_can_validate = true;
            }

            this.authn_can_edit = true;
        });
    }

    public void load () {
        this.db_get.bind_text (1, "server_url");
        if (this.db_get.step () == Sqlite.ROW) {
            this.server_url = this.db_get.column_text (0);
        } else {
            this.server_url = "";
        }
        assert (this.db_get.reset () == Sqlite.OK);

        this.db_get.bind_text (1, "username");
        if (this.db_get.step () == Sqlite.ROW) {
            this.username = this.db_get.column_text (0);
        } else {
            this.username = "";
        }
        assert (this.db_get.reset () == Sqlite.OK);

        this.db_get.bind_text (1, "token");
        if (this.db_get.step () == Sqlite.ROW) {
            this.token = this.db_get.column_text (0);
        } else {
            this.token = "";
        }
        assert (this.db_get.reset () == Sqlite.OK);

        this.db_get.bind_text (1, "salt");
        if (this.db_get.step () == Sqlite.ROW) {
            this.salt = this.db_get.column_text (0);
        } else {
            this.salt = "";
        }
        assert (this.db_get.reset () == Sqlite.OK);

        this.password = "";

        // first connection
        this.authn_can_validate = true;
        this.on_authn_validate_activated ();
    }

    private void salt_password (string password, out string token, out string salt) {
        uchar salt_bytes[8];
        randomness (8, salt_bytes);
        uchar salt_chars[17];
        for (int i = 0; i < 8; i += 1) {
            salt_chars[2*i+0] = "0123456789abcdef"[(salt_bytes[i]>>4)&0xf];
            salt_chars[2*i+1] = "0123456789abcdef"[(salt_bytes[i]>>0)&0xf];
        }
        salt_chars[16] = 0;
        var checksum = new Checksum (ChecksumType.MD5);
        checksum.update ((uchar[]) password, -1);
        checksum.update (salt_chars, 16);

        token = checksum.get_string ();
        salt = (string) salt_chars;
    }

    public void save () {
        this.db_set.bind_text (1, "server_url");
        this.db_set.bind_text (2, this.server_url);
        assert (this.db_set.step () == Sqlite.DONE);
        assert (this.db_set.reset () == Sqlite.OK);

        this.db_set.bind_text (1, "username");
        this.db_set.bind_text (2, this.username);
        assert (this.db_set.step () == Sqlite.DONE);
        assert (this.db_set.reset () == Sqlite.OK);

        this.db_set.bind_text (1, "token");
        this.db_set.bind_text (2, this.token);
        assert (this.db_set.step () == Sqlite.DONE);
        assert (this.db_set.reset () == Sqlite.OK);

        this.db_set.bind_text (1, "salt");
        this.db_set.bind_text (2, this.salt);
        assert (this.db_set.step () == Sqlite.DONE);
        assert (this.db_set.reset () == Sqlite.OK);

        this.password = "";
    }
}