-- LegacyWorlds Beta 6
-- PostgreSQL database scripts
--
-- Resource definitions
--
-- Copyright(C) 2004-2011, DeepClone Development
-- --------------------------------------------------------


/*
 * Common resource definitions
 * ----------------------------
 * 
 * The defs.resources table is used to describe the part of a resource's
 * definition that's idependant 
 */

CREATE TABLE defs.resources(
	/* The resource identifier is a reference to an I18N string that
	 * represents the resource's name. It also serves as the table's
	 * primary key.
	 */
	resource_name_id			INT NOT NULL PRIMARY KEY ,

	/* Identifier of an I18N string which serves as the resource's
	 * description. 
	 */
	resource_description_id		INT NOT NULL ,

	/* Identifier of an I18N string that names the resource's category. This
	 * field may be NULL for resources that do not belong to a category. 
	 */
	resource_category_id		INT ,

	/* The weight is used when sorting resources. For resources that do not
	 * have a category, it is used directly. Otherwise, categories themselves
	 * are sorted by average weight of their contents, and resources in
	 * categories are sorted by weight.
	 */
	resource_weight				INT NOT NULL
									CHECK ( resource_weight > 0 )
);

CREATE UNIQUE INDEX idx_resources_description
	ON defs.resources( resource_description_id );
CREATE INDEX idx_resources_category
	ON defs.resources( resource_category_id );
CREATE INDEX idx_resources_weight
	ON defs.resources( resource_weight );

ALTER TABLE defs.resources
	ADD CONSTRAINT fk_resources_name
		FOREIGN KEY ( resource_name_id ) REFERENCES defs.strings ,
	ADD CONSTRAINT fk_resources_description
		FOREIGN KEY ( resource_description_id ) REFERENCES defs.strings ,
	ADD CONSTRAINT fk_resources_category
		FOREIGN KEY ( resource_category_id ) REFERENCES defs.strings;



/*
 * Natural resources
 * ------------------
 * 
 * This table contains additional resource information that is used for
 * natural resources only. These fields are used by the universe generator
 * when it creates resource providers. 
 */
CREATE TABLE defs.natural_resources (
	/* Identifier of the resource definition for this natural resource, which
	 * also serves as the primary key for this table.
	 */
	resource_name_id			INT NOT NULL PRIMARY KEY ,

	/* Presence probability, used by the universe generator to determine
	 * whether some type of resource should be added to a planet or not. The
	 * generator will try to enforce this probability on the universe in
	 * general (that is, not assigning the resource to a planet will increase
	 * the probability of it being assigned to another).
	 */
	natres_p_presence		DOUBLE PRECISION NOT NULL
								CHECK ( natres_p_presence > 0
									AND natres_p_presence < 1 ) ,

	/* Average quantity in resource providers. */
	natres_quantity_avg		DOUBLE PRECISION NOT NULL
								CHECK( natres_quantity_avg > 0 ) ,
	/* Maximal deviation from the average quantity. */
	natres_quantity_dev		DOUBLE PRECISION NOT NULL
								CHECK( natres_quantity_dev >= 0 ) ,

	/* Average extraction difficulty assigned to resource providers */
	natres_difficulty_avg	DOUBLE PRECISION NOT NULL
								CHECK( natres_difficulty_avg BETWEEN 0 AND 1 ) ,
	/* Maximal deviation from the average extraction difficulty */
	natres_difficulty_dev	DOUBLE PRECISION NOT NULL
								CHECK( natres_difficulty_dev >= 0 ) ,

	/* Average recovery rate for resource providers */
	natres_recovery_avg		DOUBLE PRECISION NOT NULL
								CHECK( natres_recovery_avg > 0
									AND natres_recovery_avg <= 1 ) ,
	/* Maximal deviation from the average recovery rate */
	natres_recovery_dev		DOUBLE PRECISION NOT NULL
								CHECK( natres_recovery_dev >= 0 ) ,
	
	/*
	 * For all values which include both an average and a maximal deviation,
	 * make sure the range defined by the deviation is still within valid
	 * boundaries for the value in question.
	 */
	CHECK( natres_quantity_avg - natres_quantity_dev > 0 ) ,
	CHECK( natres_difficulty_avg + natres_difficulty_dev <= 1 ) ,
	CHECK( natres_difficulty_avg - natres_difficulty_dev >= 0 ) ,
	CHECK( natres_recovery_avg + natres_recovery_dev <= 1 ) ,
	CHECK( natres_recovery_avg - natres_recovery_dev > 0 )
);

ALTER TABLE defs.natural_resources
	ADD CONSTRAINT fk_natres_resource
		FOREIGN KEY ( resource_name_id ) REFERENCES defs.resources;