/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/

#include "backends/keymapper/keymap.h"

#ifdef ENABLE_KEYMAPPER

#include "backends/keymapper/hardware-key.h"

#define KEYMAP_KEY_PREFIX "keymap_"

namespace Common {

Keymap::Keymap(const Keymap& km) : _actions(km._actions), _keymap(), _configDomain(0) {
	List<Action*>::iterator it;

	for (it = _actions.begin(); it != _actions.end(); ++it) {
		const HardwareKey *hwKey = (*it)->getMappedKey();

		if (hwKey) {
			_keymap[hwKey->key] = *it;
		}
	}
}

Keymap::~Keymap() {
	List<Action*>::iterator it;

	for (it = _actions.begin(); it != _actions.end(); ++it)
		delete *it;
}

void Keymap::addAction(Action *action) {
	if (findAction(action->id))
		error("Action with id %s already in KeyMap", action->id);

	_actions.push_back(action);
}

void Keymap::registerMapping(Action *action, const HardwareKey *hwKey) {
	HashMap<KeyState, Action*>::iterator it;

	it = _keymap.find(hwKey->key);

	// if key is already mapped to a different action then un-map it
	if (it != _keymap.end() && action != it->_value) {
		it->_value->mapKey(0);
	}

	_keymap[hwKey->key] = action;
}

void Keymap::unregisterMapping(Action *action) {
	const HardwareKey *hwKey = action->getMappedKey();

	if (hwKey) {
		_keymap.erase(hwKey->key);
	}
}

Action *Keymap::getAction(const char *id) {
	return findAction(id);
}

Action *Keymap::findAction(const char *id) {
	List<Action*>::iterator it;

	for (it = _actions.begin(); it != _actions.end(); ++it) {
		if (strncmp((*it)->id, id, ACTION_ID_SIZE) == 0)
			return *it;
	}
	return 0;
}

const Action *Keymap::findAction(const char *id) const {
	List<Action*>::const_iterator it;

	for (it = _actions.begin(); it != _actions.end(); ++it) {
		if (strncmp((*it)->id, id, ACTION_ID_SIZE) == 0)
			return *it;
	}

	return 0;
}

Action *Keymap::getMappedAction(const KeyState& ks) const {
	HashMap<KeyState, Action*>::iterator it;

	it = _keymap.find(ks);

	if (it == _keymap.end())
		return 0;
	else
		return it->_value;
}

void Keymap::setConfigDomain(ConfigManager::Domain *dom) {
	_configDomain = dom;
}

void Keymap::loadMappings(const HardwareKeySet *hwKeys) {
	if (!_configDomain)
		return;

	ConfigManager::Domain::iterator it;
	String prefix = KEYMAP_KEY_PREFIX + _name + "_";

	for (it = _configDomain->begin(); it != _configDomain->end(); ++it) {
		const String& key = it->_key;

		if (!key.hasPrefix(prefix.c_str()))
			continue;

		// parse Action ID
		const char *actionId = key.c_str() + prefix.size();
		Action *ua = getAction(actionId);

		if (!ua) {
			warning("'%s' keymap does not contain Action with ID %s",
				_name.c_str(), actionId);
			_configDomain->erase(key);

			continue;
		}

		const HardwareKey *hwKey = hwKeys->findHardwareKey(it->_value.c_str());

		if (!hwKey) {
			warning("HardwareKey with ID %s not known", it->_value.c_str());
			_configDomain->erase(key);
			continue;
		}

		ua->mapKey(hwKey);
	}
}

void Keymap::saveMappings() {
	if (!_configDomain)
		return;

	List<Action*>::const_iterator it;
	String prefix = KEYMAP_KEY_PREFIX + _name + "_";

	for (it = _actions.begin(); it != _actions.end(); ++it) {
		uint actIdLen = strlen((*it)->id);

		actIdLen = (actIdLen > ACTION_ID_SIZE) ? ACTION_ID_SIZE : actIdLen;

		String actId((*it)->id, (*it)->id + actIdLen);
		char hwId[HWKEY_ID_SIZE+1];

		memset(hwId, 0, HWKEY_ID_SIZE+1);

		if ((*it)->getMappedKey()) {
			memcpy(hwId, (*it)->getMappedKey()->hwKeyId, HWKEY_ID_SIZE);
		}
		_configDomain->setVal(prefix + actId, hwId);
	}
}

bool Keymap::isComplete(const HardwareKeySet *hwKeys) {
	List<Action*>::iterator it;
	bool allMapped = true;
	uint numberMapped = 0;

	for (it = _actions.begin(); it != _actions.end(); ++it) {
		if ((*it)->getMappedKey()) {
			numberMapped++;
		} else {
			allMapped = false;
		}
	}

	return allMapped || (numberMapped == hwKeys->size());
}

// TODO:
// - current weakness:
//     - if an action finds a key with required type but a parent action with
//       higher priority is using it, that key is never used
void Keymap::automaticMapping(HardwareKeySet *hwKeys) {
	// Create copies of action and key lists.
	List<Action*> actions(_actions);
	List<const HardwareKey*> keys(hwKeys->getHardwareKeys());

	List<Action*>::iterator actIt;
	List<const HardwareKey*>::iterator keyIt, selectedKey;

	// Remove actions and keys from local lists that have already been mapped.
	actIt = actions.begin();

	while (actIt != actions.end()) {
		Action *act = *actIt;
		const HardwareKey *key = act->getMappedKey();

		if (key) {
			keys.remove(key);
			actIt = actions.erase(actIt);
		} else {
			++actIt;
		}
	}

	// Sort remaining actions by priority.
	ActionPriorityComp priorityComp;
	sort(actions.begin(), actions.end(), priorityComp);

	// First mapping pass:
	// - Match if a key's preferred action type is the same as the action's
	// type, or vice versa.
	// - Priority is given to:
	//     - keys that match action types over key types.
	//     - keys that have not been used by parent maps.
	// - If a key has been used by a parent map the new action must have a
	//   higher priority than the parent action.
	// - As soon as the number of skipped actions equals the number of keys
	//   remaining we stop matching. This means that the second pass will assign keys
	//   to these higher priority skipped actions.
	uint skipped = 0;
	actIt = actions.begin();

	while (actIt != actions.end() && skipped < keys.size()) {
		selectedKey = keys.end();
		int matchRank = 0;
		Action *act = *actIt;

		for (keyIt = keys.begin(); keyIt != keys.end(); ++keyIt) {
			if ((*keyIt)->preferredAction == act->type && act->type != kGenericActionType) {
				Action *parentAct = getParentMappedAction((*keyIt)->key);

				if (!parentAct) {
					selectedKey = keyIt;
					break;
				} else if (parentAct->priority <= act->priority && matchRank < 3) {
					selectedKey = keyIt;
					matchRank = 3;
				}
			} else if ((*keyIt)->type == act->preferredKey && act->preferredKey != kGenericKeyType && matchRank < 2) {
				Action *parentAct = getParentMappedAction((*keyIt)->key);

				if (!parentAct) {
					selectedKey = keyIt;
					matchRank = 2;
				} else if (parentAct->priority <= act->priority && matchRank < 1) {
					selectedKey = keyIt;
					matchRank = 1;
				}
			}
		}
		if (selectedKey != keys.end()) {
			// Map action and delete action & key from local lists.
			act->mapKey(*selectedKey);
			keys.erase(selectedKey);
			actIt = actions.erase(actIt);
		} else {
			// Skip action (will be mapped in next pass).
			++actIt;
			++skipped;
		}
	}

	// Second mapping pass:
	// - Maps any remaining actions to keys
	// - priority given to:
	//     - keys that have no parent action
	//     - keys whose parent action has lower priority than the new action
	//     - keys whose parent action has the lowest priority
	// - is guaranteed to match a key if they are not all used up
	for (actIt = actions.begin(); actIt != actions.end(); ++actIt) {
		selectedKey = keys.end();

		int matchRank = 0;
		int lowestPriority = 0;
		Action *act = *actIt;

		for (keyIt = keys.begin(); keyIt != keys.end(); ++keyIt) {
			Action *parentAct = getParentMappedAction((*keyIt)->key);

			if (!parentAct) {
				selectedKey = keyIt;
				break;
			} else if (matchRank < 2) {
				if (parentAct->priority <= act->priority) {
					matchRank = 2;
					selectedKey = keyIt;
				} else if (parentAct->priority < lowestPriority || matchRank == 0) {
					matchRank = 1;
					lowestPriority = parentAct->priority;
					selectedKey = keyIt;
				}
			}
		}

		if (selectedKey != keys.end()) {
			act->mapKey(*selectedKey);
			keys.erase(selectedKey);
		} else {// no match = no keys left
			break;
		}
	}
}

Action *Keymap::getParentMappedAction(KeyState key) {
	if (_parent) {
		Action *act = _parent->getMappedAction(key);

		if (act)
			return act;
		else
			return _parent->getParentMappedAction(key);
	} else {
		return 0;
	}
}

} // End of namespace Common

#endif // #ifdef ENABLE_KEYMAPPER