CREATE SEQUENCE activity_seq;

CREATE TABLE patch_audit (
	patch_id				integer not null,
	change_type				varchar not null,
	changed_fields			varchar[] not null,
	commitfest_id	        integer not null,
	original_name			varchar not null,
	from_commitfest_id		integer,
	to_commitfest_id		integer,
	commitfest_topic_id     integer not null,
	name					varchar not null,
	patch_status_id			integer not null,
	author   				varchar not null,
	reviewers				varchar not null,
	date_closed				date,
	last_updater			varchar,
	last_updated_time		timestamp with time zone not null
);
ALTER TABLE patch_audit ADD COLUMN activity_id INTEGER NOT NULL
	DEFAULT nextval('activity_seq');
ALTER TABLE patch_audit ADD COLUMN committer VARCHAR NOT NULL
	DEFAULT '';

CREATE OR REPLACE FUNCTION patch_audit() RETURNS trigger AS $$
DECLARE
	cf varchar[] := '{}'::varchar[];
	acid integer;
	cid integer;
	oname varchar;
BEGIN
	IF (TG_OP = 'DELETE') THEN
		NEW := OLD;
		NEW.last_updated_time := now();
	END IF;
	IF (TG_OP = 'UPDATE') THEN
		IF (OLD.last_updated_time = NEW.last_updated_time) THEN
			-- Some kind of system update, just ignore it.
			RETURN NULL;
		END IF;
		cf := CASE WHEN OLD.commitfest_topic_id != NEW.commitfest_topic_id
				   THEN '{commitfest_topic_id}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.name != NEW.name
				   THEN '{name}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.patch_status_id != NEW.patch_status_id
				   THEN '{patch_status_id}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.author != NEW.author
				   THEN '{author}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.reviewers != NEW.reviewers
				   THEN '{reviewers}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.committer != NEW.committer
				   THEN '{committer}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.date_closed IS DISTINCT FROM NEW.date_closed
				   THEN '{date_closed}'::varchar[]
				   ELSE '{}'::varchar[] END;
		SELECT INTO cid
			commitfest_id
		FROM
			commitfest_topic
		WHERE
			id = NEW.commitfest_topic_id;
		SELECT INTO acid
			commitfest_id
		FROM
			commitfest_topic
		WHERE
			id = OLD.commitfest_topic_id;
		oname := OLD.name;
	ELSE
		SELECT INTO cid, acid
			commitfest_id, commitfest_id
		FROM
			commitfest_topic
		WHERE
			id = NEW.commitfest_topic_id;
		oname := NEW.name;
	END IF;
	IF (TG_OP = 'INSERT') THEN
		cf := ARRAY['commitfest_id', 'commitfest_topic_id', 'name',
			'patch_status_id', 'author', 'reviewers',
			'committer', 'date_closed'];
	END IF;
	INSERT INTO patch_audit
		(patch_id, change_type, changed_fields, commitfest_id, original_name,
		 to_commitfest_id, commitfest_topic_id, name,
		 patch_status_id, author, reviewers, committer, date_closed,
		 last_updater, last_updated_time)
	VALUES
		(NEW.id, TG_OP, cf, acid, oname,
		 CASE WHEN cid != acid THEN cid ELSE NULL END,
		 NEW.commitfest_topic_id, NEW.name, NEW.patch_status_id, NEW.author,
		 NEW.reviewers, NEW.committer, NEW.date_closed, NEW.last_updater,
		 NEW.last_updated_time);
	-- For an update that changes the CommitFest, we enter two audit records,
	-- one under each CommitFest.
	IF (cid != acid) THEN
		INSERT INTO patch_audit
			(patch_id, change_type, changed_fields, commitfest_id,
			 original_name,
			 from_commitfest_id, commitfest_topic_id, name,
			 patch_status_id, author, reviewers, committer, date_closed,
			 last_updater, last_updated_time)
		VALUES
			(NEW.id, TG_OP, cf, cid, oname, acid,
			 NEW.commitfest_topic_id, NEW.name, NEW.patch_status_id, NEW.author,
			 NEW.reviewers, NEW.committer, NEW.date_closed, NEW.last_updater,
			 NEW.last_updated_time);
	END IF;
	RETURN NULL;
END
$$ LANGUAGE plpgsql;

CREATE TRIGGER patch_audit
	AFTER INSERT OR UPDATE OR DELETE ON patch
	FOR EACH ROW EXECUTE PROCEDURE patch_audit();

CREATE OR REPLACE FUNCTION patch_audit_details(patch_audit) RETURNS text AS $$
DECLARE
	v varchar[];
BEGIN
	IF ('name' = ANY($1.changed_fields)) THEN
		v := v || ('Name = ' || $1.name)::varchar;
	END IF;
	IF ($1.from_commitfest_id IS NOT NULL) THEN
		v := v || ('Moved From CommitFest = ' || COALESCE((SELECT name FROM
			commitfest WHERE id = $1.from_commitfest_id), '???'))::varchar;
	END IF;
	IF ($1.to_commitfest_id IS NOT NULL) THEN
		v := v || ('Moved To CommitFest = ' || COALESCE((SELECT name FROM
			commitfest WHERE id = $1.to_commitfest_id), '???'))::varchar;
	END IF;
	IF ('commitfest_topic_id' = ANY($1.changed_fields)) THEN
		v := v || ('Topic = ' || COALESCE((SELECT name FROM commitfest_topic
			WHERE id = $1.commitfest_topic_id), '???'))::varchar;
	END IF;
	IF ('patch_status_id' = ANY($1.changed_fields)) THEN
		v := v || ('Patch Status = ' || COALESCE((SELECT name FROM patch_status
			WHERE id = $1.patch_status_id), '???'))::varchar;
	END IF;
	IF ('author' = ANY($1.changed_fields)) THEN
		v := v || ('Author = ' || $1.author)::varchar;
	END IF;
	IF ('reviewers' = ANY($1.changed_fields)) THEN
		v := v || ('Reviewers = ' || CASE WHEN $1.reviewers = '' THEN 'Nobody'
			ELSE $1.reviewers END)::varchar;
	END IF;
	IF ('committer' = ANY($1.changed_fields)) THEN
		v := v || ('Committer = ' || CASE WHEN $1.committer = '' THEN 'Nobody'
			ELSE $1.committer END)::varchar;
	END IF;
	IF ('date_closed' = ANY($1.changed_fields)) THEN
		v := v || ('Date Closed = '
			|| COALESCE($1.date_closed::varchar, 'NULL'))::varchar;
	END IF;
	RETURN array_to_string(v, ', ');
END
$$ LANGUAGE plpgsql;

CREATE TABLE patch_comment_audit (
	id						integer not null,
	patch_id				integer not null,
	change_type				varchar not null,
	changed_fields			varchar[] not null,
	commitfest_id	        integer not null,
	patch_name				varchar not null,
	patch_comment_type_id	integer not null,
	message_id				varchar,
	content					varchar,
	last_updater			varchar,
	last_updated_time		timestamp with time zone not null
);
ALTER TABLE patch_comment_audit ADD COLUMN activity_id INTEGER NOT NULL
	DEFAULT nextval('activity_seq');

CREATE OR REPLACE FUNCTION patch_comment_audit() RETURNS trigger AS $$
DECLARE
	cf varchar[] := '{}'::varchar[];
	cid integer;
	pname varchar;
BEGIN
	IF (TG_OP = 'DELETE') THEN
		NEW := OLD;
		NEW.last_updated_time := now();
	END IF;
	IF (TG_OP = 'UPDATE') THEN
		IF (OLD.last_updated_time = NEW.last_updated_time) THEN
			-- Some kind of system update, just ignore it.
			RETURN NULL;
		END IF;
		cf := CASE WHEN OLD.patch_comment_type_id != NEW.patch_comment_type_id
				   THEN '{patch_comment_type_id}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.message_id != NEW.message_id
				   THEN '{message_id}'::varchar[]
				   ELSE '{}'::varchar[] END
		   || CASE WHEN OLD.content != NEW.content
				   THEN '{content}'::varchar[]
				   ELSE '{}'::varchar[] END;
	END IF;
	SELECT INTO cid, pname
		t.commitfest_id, p.name
	FROM
		patch p
		JOIN commitfest_topic t ON p.commitfest_topic_id = t.id
	WHERE
		p.id = NEW.patch_id;
	IF (TG_OP = 'INSERT') THEN
		cf := ARRAY['patch_comment_type_id', 'message_id', 'content' ];
	END IF;
	INSERT INTO patch_comment_audit
		(id, patch_id, change_type, changed_fields, commitfest_id, patch_name,
		 patch_comment_type_id, message_id, content, last_updater,
		 last_updated_time)
	VALUES
		(NEW.id, NEW.patch_id, TG_OP, cf, cid, pname,
		 NEW.patch_comment_type_id, NEW.message_id, NEW.content,
		 NEW.last_updater, NEW.last_updated_time);
	RETURN NULL;
END
$$ LANGUAGE plpgsql;

CREATE TRIGGER patch_comment_audit
	AFTER INSERT OR UPDATE OR DELETE ON patch_comment
	FOR EACH ROW EXECUTE PROCEDURE patch_comment_audit();

CREATE OR REPLACE FUNCTION patch_comment_audit_details(patch_comment_audit)
	RETURNS text AS $$
SELECT
	(SELECT name FROM patch_comment_type WHERE id = $1.patch_comment_type_id)
	|| ': ' || $1.content
	|| CASE WHEN $1.message_id != '' THEN ' (Message-ID: '
		|| $1.message_id || ')' ELSE '' END
$$ LANGUAGE sql;