-- LegacyWorlds Beta 6
-- PostgreSQL database scripts
--
-- Empire research functions and views
--
-- Copyright(C) 2004-2012, DeepClone Development
-- --------------------------------------------------------



/*
 * Implements a technology
 * ------------------------
 * 
 * This stored procedure is called when an empire attempts to implement a
 * technology. It will check the empire's resources and the technology itself,
 * then mark it as implemented if necessary. It will also add new research
 * entries if necessary.
 * 
 * Parameters:
 *		_empire			The empire's identifier
 *		_technology		The string identifier for the technology to implement
 */
DROP FUNCTION IF EXISTS emp.technology_implement( INT , TEXT );
CREATE FUNCTION emp.technology_implement( _empire INT , _technology TEXT )
		RETURNS BOOLEAN
		LANGUAGE PLPGSQL
		STRICT VOLATILE
		SECURITY DEFINER
	AS $technology_implement$

DECLARE
	_impl_data	RECORD;

BEGIN

	-- Access and lock the records
	SELECT INTO _impl_data
			technology_name_id , technology_price
		FROM emp.empires _emp
			INNER JOIN emp.technologies_v2 _tech
				ON _tech.empire_id = _emp.name_id
			INNER JOIN defs.technologies _def
				USING ( technology_name_id )
			INNER JOIN defs.strings _name
				ON _def.technology_name_id = _name.id
		WHERE _emp.name_id = _empire
			AND _name.name = _technology
			AND _tech.emptech_state = 'PENDING'
			AND _emp.cash >= _def.technology_price
		FOR UPDATE OF _emp , _tech
		FOR SHARE OF _def;
	IF NOT FOUND THEN
		RETURN FALSE;
	END IF;

	-- Implement the technology
	UPDATE emp.empires
		SET cash = cash - _impl_data.technology_price
		WHERE name_id = _empire;
	UPDATE emp.technologies_v2
		SET emptech_state = 'KNOWN'
		WHERE empire_id = _empire
			AND technology_name_id = _impl_data.technology_name_id;

	-- Insert new research
	INSERT INTO emp.technologies_v2 ( empire_id , technology_name_id )
		SELECT _empire , _valid.technology_name_id
			FROM  ( SELECT _tech.technology_name_id ,
							( COUNT(*) = COUNT(_emptech.emptech_state) ) AS emptech_has_dependencies
						FROM defs.technologies _tech
							INNER JOIN defs.technology_dependencies _deps
									USING ( technology_name_id )
							LEFT OUTER JOIN emp.technologies_v2 _emptech
									ON _emptech.technology_name_id = _deps.technology_name_id_depends
										AND _emptech.emptech_state = 'KNOWN'
										AND _emptech.empire_id = _empire
						GROUP BY _tech.technology_name_id ) _valid
				LEFT OUTER JOIN emp.technologies_v2 _emptech
					ON _emptech.empire_id = _empire
						AND _emptech.technology_name_id = _valid.technology_name_id
			WHERE _emptech.empire_id IS NULL AND _valid.emptech_has_dependencies;

	RETURN TRUE;
END;
$technology_implement$;

REVOKE EXECUTE
	ON FUNCTION emp.technology_implement( INT , TEXT )
	FROM PUBLIC;

GRANT EXECUTE
	ON FUNCTION emp.technology_implement( INT , TEXT )
	TO :dbuser;


/*
 * Compute a technology identifier
 * --------------------------------
 * 
 * This function returns the identifier of a technology as seen from the
 * player's side. The identifier is either the string identifier for the
 * technology's name, or a MD5 hash including both the empire's identifier
 * and the string identifier for "unknown" technologies.
 * 
 * Parameters:
 *		_empire		The empire's identifier
 *		_technology	The technology's string identifier
 *		_visible	TRUE if the technology is supposed to be visible, FALSE
 *						otherwise
 *
 * Returns:
 *		?			The technology's client-side identifier
 */
DROP FUNCTION IF EXISTS emp.technology_make_identifier( INT , TEXT , BOOLEAN );
CREATE FUNCTION emp.technology_make_identifier(
				_empire INT , _technology TEXT , _visible BOOLEAN )
	RETURNS TEXT
	LANGUAGE SQL
	STRICT IMMUTABLE
	SECURITY DEFINER
AS $technology_make_identifier$

	SELECT ( CASE
		WHEN $3 THEN
			$2
		ELSE
			md5( $1::TEXT || ' (making hash less obvious) ' || $2 )
	END );

$technology_make_identifier$;

REVOKE EXECUTE
	ON FUNCTION emp.technology_make_identifier( INT , TEXT , BOOLEAN )
	FROM PUBLIC;

GRANT EXECUTE
	ON FUNCTION emp.technology_make_identifier( INT , TEXT , BOOLEAN )
	TO :dbuser;


/*
 * Initialise a research priorities update
 * ----------------------------------------
 * 
 * This stored procedure prepares a temporary table which is used to update
 * an empire's research priorities.
 *
 * Parameters:
 *		_empire		The empire's identifier
 *
 * Returns:
 *		?			TRUE if the empire exists, is not on vacation mode and has
 *						in-progress research, FALSE otherwise.
 */
DROP FUNCTION IF EXISTS emp.resprio_update_start( INT );
CREATE FUNCTION emp.resprio_update_start( _empire INT )
		RETURNS BOOLEAN
		LANGUAGE PLPGSQL
		STRICT VOLATILE
		SECURITY DEFINER
	AS $resprio_update_start$
BEGIN

	-- Create temporary table
	CREATE TEMPORARY TABLE rprio_update(
		_empire_id			INT ,
		_technology_name_id	INT ,
		_emptech_id			TEXT ,
		_emptech_priority	INT
	) ON COMMIT DROP;

	-- Lock records and fill table
	INSERT INTO rprio_update (
			_empire_id , _technology_name_id , _emptech_id , _emptech_priority
		) SELECT _emp.name_id , _tech.technology_name_id ,
				emp.technology_make_identifier( empire_id , _str.name , emptech_visible ) ,
				_etech.emptech_priority
			FROM emp.empires _emp
				INNER JOIN emp.technologies_v2 _etech
					ON _etech.empire_id = _emp.name_id
						AND _etech.emptech_state = 'RESEARCH'
				INNER JOIN defs.technologies _tech
					USING ( technology_name_id )
				INNER JOIN emp.technology_visibility_view _vis
					USING ( empire_id , technology_name_id )
				INNER JOIN defs.strings _str
					ON _str.id = _tech.technology_name_id
				INNER JOIN naming.empire_names _ename
					ON _ename.id = _emp.name_id
				LEFT OUTER JOIN users.vacations _vac
					ON _vac.account_id = _ename.owner_id
						AND _vac.status = 'PROCESSED'
			WHERE _emp.name_id = _empire AND _vac.account_id IS NULL
			FOR UPDATE OF _emp , _etech
			FOR SHARE OF _tech , _str , _ename;

	RETURN FOUND;
END;
$resprio_update_start$;

REVOKE EXECUTE
	ON FUNCTION emp.resprio_update_start( INT )
	FROM PUBLIC;

GRANT EXECUTE
	ON FUNCTION emp.resprio_update_start( INT )
	TO :dbuser;


/*
 * Set the priority of some research
 * ----------------------------------
 * 
 * This stored procedure updates the priority of some in-progress empire
 * research. It will only function correctly if emp.resprio_update_start() was
 * already executed.
 * 
 * Parameters:
 *		_technology		The client-side identifier of the technology, as
 *							returned by emp.technology_make_identifier()
 *		_priority		The priority to assign to the technology
 *
 * Returns:
 *		?				TRUE if the technology was found, FALSE if it wasn't.
 */
DROP FUNCTION IF EXISTS emp.resprio_update_set( TEXT , INT );
CREATE FUNCTION emp.resprio_update_set( _technology TEXT , _priority INT )
		RETURNS BOOLEAN
		LANGUAGE PLPGSQL
		STRICT VOLATILE
		SECURITY DEFINER
	AS $resprio_update_set$
BEGIN
	
	UPDATE rprio_update
		SET _emptech_priority = _priority
		WHERE _emptech_id = _technology;
	RETURN FOUND;

END;
$resprio_update_set$;

REVOKE EXECUTE
	ON FUNCTION emp.resprio_update_set( TEXT , INT )
	FROM PUBLIC;

GRANT EXECUTE
	ON FUNCTION emp.resprio_update_set( TEXT , INT )
	TO :dbuser;


/*
 * Apply an update to research priorities
 * ---------------------------------------
 * 
 * This stored procedure applies changes listed in the temporary research
 * priority table by updating the actual table with the new values.
 * 
 * Returns:
 *		?		TRUE if the update was valid, FALSE if one of the updated
 *					values was incorrect
 */
DROP FUNCTION IF EXISTS emp.resprio_update_apply( );
CREATE FUNCTION emp.resprio_update_apply( )
		RETURNS BOOLEAN
		LANGUAGE PLPGSQL
		STRICT VOLATILE
		SECURITY DEFINER
	AS $resprio_update_apply$
BEGIN
	
	UPDATE emp.technologies_v2
		SET emptech_priority = _emptech_priority
		FROM rprio_update
		WHERE _empire_id = empire_id
			AND _technology_name_id = technology_name_id;
	RETURN TRUE;

EXCEPTION

	WHEN check_violation THEN
		RETURN FALSE;

END;
$resprio_update_apply$;

REVOKE EXECUTE
	ON FUNCTION emp.resprio_update_apply( )
	FROM PUBLIC;

GRANT EXECUTE
	ON FUNCTION emp.resprio_update_apply( )
	TO :dbuser;



/*
 * Compute an empire's total research points
 * ------------------------------------------
 * 
 * Obtain an empire's total research points by adding the happiness-adjusted
 * value for each planet, then applying the global modifier for vacation mode
 * if necessary.
 *
 * FIXME: time factor is hard-coded
 * 
 * Parameters:
 *		_empire			The empire's identifier
 *		_on_vacation	TRUE if the player is on vacation, FALSE otherwise
 *
 * Returns:
 *		?				The amount of research points.
 */
DROP FUNCTION IF EXISTS emp.research_get_points( INT , BOOLEAN );
CREATE FUNCTION emp.research_get_points( _empire INT , _on_vacation BOOLEAN )
	RETURNS DOUBLE PRECISION
	LANGUAGE SQL
	STRICT STABLE
	SECURITY INVOKER
AS $research_get_points$

	SELECT SUM( verse.adjust_production(
					_planet.population * sys.get_constant( 'game.research.basePoints' ) ,
					_happiness.current / _planet.population
				) ) * ( CASE
					WHEN $2 THEN
						sys.get_constant( 'game.research.vacation' )
					ELSE
						1.0
				END )::DOUBLE PRECISION
		FROM emp.planets _emp_planet
			INNER JOIN verse.planets _planet
				ON _emp_planet.planet_id = _planet.name_id
			INNER JOIN verse.planet_happiness _happiness
				USING ( planet_id )
		WHERE _emp_planet.empire_id = $1;

$research_get_points$;

REVOKE EXECUTE
	ON FUNCTION emp.research_get_points( INT , BOOLEAN )
	FROM PUBLIC;





/*
 * Technology visibility view
 * ---------------------------
 * 
 * This view can be used to determine whether entries from empires' research
 * and technologies table are fully visible or only displayed as "unknown
 * technologies".
 * 
 * Columns:
 *		empire_id			The empire's identifier
 *		technology_name_id	The technology's identifier
 *		emptech_visible		TRUE if the technology's details are visible,
 *								FALSE if they should be hidden
 */
DROP VIEW IF EXISTS emp.technology_visibility_view CASCADE;
CREATE VIEW emp.technology_visibility_view
	AS SELECT empire_id , technology_name_id ,
			( emptech_state <> 'RESEARCH'
				OR emptech_points >= sys.get_constant( 'game.research.visibility.points' )
				OR emptech_points / technology_points::DOUBLE PRECISION >= sys.get_constant( 'game.research.visibility.ratio' )
			) AS emptech_visible
		FROM emp.technologies_v2
			INNER JOIN defs.technologies
				USING ( technology_name_id );



/*
 * Research weights
 * -----------------
 * 
 * This view computes weights based on priorities for each in-progress
 * research.
 * 
 * Columns:
 *		empire_id			The empire's identifier
 *		technology_name_id	The technology's identifier
 *		emptech_weight		The weight
 */
DROP VIEW IF EXISTS emp.research_weights_view CASCADE;
CREATE VIEW emp.research_weights_view
	AS SELECT empire_id , technology_name_id ,
			POW( sys.get_constant( 'game.research.weightBase' ) ,
					emptech_priority ) AS emptech_weight
		FROM emp.technologies_v2
		WHERE emptech_state = 'RESEARCH';

/*
 * Total research weights
 * -----------------------
 * 
 * This view computes total research weights for each empire with in-progress
 * research.
 * 
 * Columns:
 *		empire_id				The empire's identifier
 *		emptech_total_weight	The total research weight
 */
DROP VIEW IF EXISTS emp.research_total_weights_view CASCADE;
CREATE VIEW emp.research_total_weights_view
	AS SELECT empire_id , SUM( emptech_weight ) AS emptech_total_weight
		FROM emp.research_weights_view
		GROUP BY empire_id;


/*
 * Empire research and technologies
 * ---------------------------------
 * 
 * This view lists empires' research and technologies, along with their
 * current state.
 * 
 * Columns:
 *		empire_id			The empire's identifier
 *		emptech_id			An identifier for the technology, which is either
 *								the string identifier of the technology's name
 *								or a MD5 hash if the technology is not
 *								supposed to be visible
 *		emptech_state		The state of the technology, straight from the
 *								empire technology table
 *		emptech_visible		Whether the technology is supposed to be visible
 *								or not
 *		technology_category	The string identifier of the technology's category
 *		technology_name		The string identifier of the technology's name,
 *								or NULL if the technology is not supposed to
 *								be visible
 *		technology_description	The string identifier of the technology's name,
 *									or NULL if the technology is not supposed
 *									to be visible
 *		emptech_points		The amount of points accumulated while researching
 *								the technology, or NULL if the technology is
 *								not supposed to be visible
 *		emptech_priority	The current research priority, or NULL if the
 *								technology is no longer being researched
 *		emptech_ratio		The percentage of points accumulated while
 *								researching the technology, or NULL if the
 *								technology is no longer being researched
 *		technology_price	The monetary price of the technology, or NULL if
 *								the technology is not supposed to be visible
 *		technology_dependencies	The technology's dependencies from the
 *									dependencies view
 *		technology_buildings	The buildings which are unlocked when the
 *									technology is implemented
 */
DROP VIEW IF EXISTS emp.technologies_v2_view CASCADE;
CREATE VIEW emp.technologies_v2_view
	AS SELECT empire_id ,
			emp.technology_make_identifier( empire_id , _name_str.name , emptech_visible ) AS emptech_id ,
			emptech_state ,
			emptech_visible ,
			_cat_str.name AS technology_category ,
			( CASE
				WHEN emptech_visible THEN
					_name_str.name
				ELSE
					NULL::TEXT
			END ) AS technology_name ,
			( CASE
				WHEN emptech_visible THEN
					_descr_str.name
				ELSE
					NULL::TEXT
			END ) AS technology_description ,
			( CASE
				WHEN emptech_state <> 'RESEARCH' then
					technology_points
				WHEN emptech_visible THEN
					FLOOR( emptech_points )::BIGINT
				ELSE
					NULL::BIGINT
			END ) AS emptech_points ,
			emptech_priority ,
			( CASE
				WHEN emptech_state = 'RESEARCH' THEN
					FLOOR( 100.0 * emptech_points / technology_points::DOUBLE PRECISION )::INT
				ELSE
					NULL::INT
			END ) AS emptech_ratio ,
			( CASE
				WHEN emptech_visible THEN
					technology_price
				ELSE
					NULL::INT
			END ) AS technology_price ,
			technology_dependencies ,
			( CASE
				WHEN emptech_visible THEN
					technology_buildings
				ELSE
					''
			END ) AS technology_buildings
		FROM emp.technologies_v2
			INNER JOIN emp.technology_visibility_view
				USING ( technology_name_id , empire_id )
			INNER JOIN defs.technologies _tech
				USING ( technology_name_id )
			INNER JOIN defs.technology_dependencies_view
				USING ( technology_name_id )
			INNER JOIN defs.technology_buildings_view
				USING ( technology_name_id )
			INNER JOIN defs.strings _name_str
				ON _name_str.id = _tech.technology_name_id
			INNER JOIN defs.strings _cat_str
				ON _cat_str.id = _tech.technology_category_id
			INNER JOIN defs.strings _descr_str
				ON _descr_str.id = _tech.technology_description_id;

GRANT SELECT
	ON emp.technologies_v2_view
	TO :dbuser;