/*
 * key.hh - Definition of the base Key classes
 * libhscript, the HorizonScript library for
 * Project Horizon
 *
 * Copyright (c) 2019-2020 Adélie Linux and contributors.  All rights reserved.
 * This code is licensed under the AGPL 3.0 license, as noted in the
 * LICENSE-code file in the root directory of this repository.
 *
 * SPDX-License-Identifier: AGPL-3.0-only
 */

#ifndef __HSCRIPT_KEY_HH_
#define __HSCRIPT_KEY_HH_

#include <string>
#include "script.hh"

namespace Horizon {
namespace Keys {

/*! Base Key class, used by all Keys.
 * A Getter method is not provided in this base Key class, because each Key may
 * return a different type of data.  For example, `network` may return `bool`.
 */
class Key {
protected:
    /*! The script that owns this Key. */
    const Script *script;
    /*! The line number where this Key appeared. */
    const ScriptLocation pos;
    Key(const Script *_s, const ScriptLocation &_p) : script{_s}, pos{_p} {}
public:
    virtual ~Key();

    /*! Create the Key object with the specified data as the entire value.
     * @param data      The value associated with the key.
     * @param pos       The location where the key occurs.
     * @param errors    Output variable: if not nullptr, ++ on each error.
     * @param warnings  Output variable: if not nullptr, ++ on each warning.
     * @returns nullptr if data is unparsable, otherwise a pointer to a Key.
     */
#define UNUSED __attribute__((unused))
    /* LCOV_EXCL_START */
    static Key *parseFromData(const std::string &data UNUSED,
                              const ScriptLocation &pos UNUSED,
                              int *errors UNUSED, int *warnings UNUSED,
                              const Script *s UNUSED) {
        return nullptr;
    }
    /* LCOV_EXCL_STOP */
#undef UNUSED

    /*! Determines if the data associated with the Key is valid. */
    virtual bool validate() const = 0;

    /*! Executes the action associated with this Key.
     * @note Will always return `false` if `validate` is `false`.
     */
    virtual bool execute() const = 0;

    const ScriptLocation where() const { return this->pos; }
};


/*! Base Key class that parses and handles Boolean values.
 * All values passed in are lowercased.  Delimiters are not allowed.
 * Truthy values: "true" "yes" "1"
 * Falsy values: "false" "no" "0"
 * Any other values will be considered invalid.
 */
class BooleanKey : public Key {
protected:
    const bool value;
    BooleanKey(const Script *_s, const ScriptLocation &_p, bool my_value) :
        Key{_s, _p}, value{my_value} {}

    /*! Parse a string into a boolean.
     * @param what      The string to attempt parsing.
     * @param where     The location of the key.
     * @param key       The name of the key.
     * @param out       Output variable: will contain the value.
     * @returns true if value is parsed successfully, false otherwise.
     */
    static bool parse(const std::string &what, const ScriptLocation &where,
                      const std::string &key, bool *out);
public:
    /*! Determines if the Key is set or not.
     * @returns true if the Key is truthy, false otherwise.
     */
    bool test() const { return this->value; }

    /*! Key will fail to init if valid is invalid. */
    bool validate() const override;
};


/*! Base Key class that parses and handles single string values. */
class StringKey : public Key {
protected:
    const std::string _value;
    StringKey(const Script *_s, const ScriptLocation &_p,
              const std::string &my_str) : Key{_s, _p}, _value{my_str} {}

public:
    /*! Retrieve the value of this key. */
    const std::string value() const { return this->_value; }

    /*! By default, key will be considered valid since it parsed.
     * This method should be overridden when further consideration is needed.
     */
    bool validate() const override;
};

}
}

#endif