CREATE SCHEMA http;
/*
The purpose of this schema, tables, and associated roles to process HTTP responses.
I may even include a table to keep track of the XML responses
*/

/*
Add a role to manage permissions on the http schema
*/
CREATE ROLE http_requestor;

GRANT CONNECT ON DATABASE aact_db to http_requestor;

GRANT USAGE ON SCHEMA http TO http_requestor;

GRANT INSERT,SELECT ON ALL TABLES IN SCHEMA http TO http_requestor;


/* Create tables related to http requests
As not every request will have an xml doc, split them.
*/

CREATE TABLE IF NOT EXISTS http.responses (
    id SERIAL PRIMARY KEY, 
    nct_id VARCHAR(15),
    version_a SMALLINT,
    version_b SMALLINT,
    url VARCHAR(255),
    response_code SMALLINT,
    response_date TIMESTAMP WITH TIME ZONE,
    html TEXT
    );




-- Type: history_download_status
-- DROP TYPE IF EXISTS http.history_download_status;

CREATE TYPE http.history_download_status AS ENUM
    ('Ignored', 'Of Interest', 'Reserved', 'Downloaded', 'Incomplete');

ALTER TYPE http.history_download_status
    OWNER TO root;

COMMENT ON TYPE http.history_download_status
    IS 'Records the status of the downloaded history from clinicaltrials.gov';

/*
Table: http.download_status

Creates and then initializes the table to record history download status.
*/

--DROP TABLE IF EXISTS http.download_status;

CREATE TABLE IF NOT EXISTS http.download_status
(
    id SERIAL NOT NULL,
    nct_id character varying(15) COLLATE pg_catalog."default" NOT NULL,
    status http.history_download_status NOT NULL DEFAULT 'Ignored'::http.history_download_status,
    update_timestamp timestamp with time zone DEFAULT now(),
    CONSTRAINT download_status_pkey PRIMARY KEY (id),
    CONSTRAINT "nct_id link" FOREIGN KEY (nct_id)
        REFERENCES ctgov.studies (nct_id) MATCH SIMPLE
        ON UPDATE NO ACTION
        ON DELETE NO ACTION
)

TABLESPACE pg_default;

ALTER TABLE IF EXISTS http.download_status
    OWNER to root;

COMMENT ON TABLE http.download_status
    IS 'Records the download status for each trial''s history';


INSERT INTO http.download_status (nct_id, status)
SELECT DISTINCT nct_id, 'Ignored'::http.history_download_status 
FROM ctgov.studies;



/*
Views to allow downloader programs to identify what to download.
*/

-- View: http.most_recent_download_status

-- DROP VIEW http.most_recent_download_status;

CREATE OR REPLACE VIEW http.most_recent_download_status
 AS
 SELECT t.nct_id,
    t.status,
    t.update_timestamp
   FROM ( SELECT download_status.id,
            download_status.nct_id,
            download_status.status,
            download_status.update_timestamp,
            row_number() OVER (PARTITION BY download_status.nct_id ORDER BY download_status.update_timestamp DESC) AS rn
           FROM http.download_status) t
  WHERE t.rn = 1
  ORDER BY t.nct_id;

ALTER TABLE http.most_recent_download_status
    OWNER TO root;
COMMENT ON VIEW http.most_recent_download_status
    IS 'List of most recent download status';



-- View: http.trials_to_download

-- DROP VIEW http.trials_to_download;

CREATE OR REPLACE VIEW http.trials_to_download
 AS
 SELECT most_recent_download_status.nct_id
   FROM http.most_recent_download_status
  WHERE most_recent_download_status.status = 'Of Interest'::http.history_download_status;

ALTER TABLE http.trials_to_download
    OWNER TO root;
COMMENT ON VIEW http.trials_to_download
    IS 'List of trials for which the history needs downloaded';