CREATE TABLE hdb_catalog.hdb_version (
    version TEXT NOT NULL,
    upgraded_on TIMESTAMPTZ NOT NULL
);

CREATE UNIQUE INDEX hdb_version_one_row
ON hdb_catalog.hdb_version((version IS NOT NULL));

CREATE TABLE hdb_catalog.hdb_table
(
    table_schema TEXT,
    table_name TEXT,
    is_system_defined boolean default false,

    PRIMARY KEY (table_schema, table_name)
);

CREATE FUNCTION hdb_catalog.hdb_table_oid_check() RETURNS trigger AS
$function$
  BEGIN
    IF (EXISTS (SELECT 1 FROM information_schema.tables st WHERE st.table_schema = NEW.table_schema AND st.table_name = NEW.table_name)) THEN
      return NEW;
    ELSE
      RAISE foreign_key_violation using message = 'table_schema, table_name not in information_schema.tables';
      return NULL;
    END IF;
  END;
$function$
LANGUAGE plpgsql;

CREATE TRIGGER hdb_table_oid_check BEFORE INSERT OR UPDATE ON hdb_catalog.hdb_table
       FOR EACH ROW EXECUTE PROCEDURE hdb_catalog.hdb_table_oid_check();

CREATE TABLE hdb_catalog.hdb_relationship
(
    table_schema TEXT,
    table_name TEXT,
    rel_name   TEXT,
    rel_type   TEXT CHECK (rel_type IN ('object', 'array')),
    rel_def    JSONB NOT NULL,
    comment    TEXT NULL,
    is_system_defined boolean default false,

    PRIMARY KEY (table_schema, table_name, rel_name),
    FOREIGN KEY (table_schema, table_name) REFERENCES hdb_catalog.hdb_table(table_schema, table_name)
);

CREATE TABLE hdb_catalog.hdb_permission
(
    table_schema TEXT,
    table_name TEXT,
    role_name  TEXT,
    perm_type  TEXT CHECK(perm_type IN ('insert', 'select', 'update', 'delete')),
    perm_def   JSONB NOT NULL,
    comment    TEXT NULL,
    is_system_defined boolean default false,

    PRIMARY KEY (table_schema, table_name, role_name, perm_type),
    FOREIGN KEY (table_schema, table_name) REFERENCES hdb_catalog.hdb_table(table_schema, table_name)
);

CREATE VIEW hdb_catalog.hdb_permission_agg AS
SELECT
    table_schema,
    table_name,
    role_name,
    json_object_agg(perm_type, perm_def) as permissions
FROM
    hdb_catalog.hdb_permission
GROUP BY
    table_schema, table_name, role_name;

CREATE TABLE hdb_catalog.hdb_query_template
(
    template_name TEXT PRIMARY KEY,
    template_defn JSONB NOT NULL,
    comment    TEXT NULL,
    is_system_defined boolean default false
);

CREATE VIEW hdb_catalog.hdb_foreign_key_constraint AS
SELECT
    q.table_schema :: text,
    q.table_name :: text,
    q.constraint_name :: text,
    hdb_catalog.first(q.constraint_oid) :: integer as constraint_oid,
    hdb_catalog.first(q.ref_table_table_schema) :: text as ref_table_table_schema,
    hdb_catalog.first(q.ref_table) :: text as ref_table,
    json_object_agg(ac.attname, afc.attname) as column_mapping,
    hdb_catalog.first(q.confupdtype) :: text as on_update,
    hdb_catalog.first(q.confdeltype) :: text as on_delete
FROM
    (SELECT
        ctn.nspname AS table_schema,
        ct.relname AS table_name,
        r.conrelid AS table_id,
        r.conname as constraint_name,
        r.oid as constraint_oid,
        cftn.nspname AS ref_table_table_schema,
        cft.relname as ref_table,
        r.confrelid as ref_table_id,
        r.confupdtype,
        r.confdeltype,
        UNNEST (r.conkey) AS column_id,
        UNNEST (r.confkey) AS ref_column_id
    FROM
        pg_catalog.pg_constraint r
        JOIN pg_catalog.pg_class ct
          ON r.conrelid = ct.oid
        JOIN pg_catalog.pg_namespace ctn
          ON ct.relnamespace = ctn.oid
        JOIN pg_catalog.pg_class cft
          ON r.confrelid = cft.oid
        JOIN pg_catalog.pg_namespace cftn
          ON cft.relnamespace = cftn.oid
    WHERE
        r.contype = 'f'
    ) q
    JOIN pg_catalog.pg_attribute ac
      ON q.column_id = ac.attnum
         AND q.table_id = ac.attrelid
    JOIN pg_catalog.pg_attribute afc
      ON q.ref_column_id = afc.attnum
         AND q.ref_table_id = afc.attrelid
GROUP BY q.table_schema, q.table_name, q.constraint_name;

CREATE VIEW hdb_catalog.hdb_check_constraint AS
SELECT
    n.nspname :: text AS table_schema,
    ct.relname :: text AS table_name,
    r.conname :: text as constraint_name,
    pg_catalog.pg_get_constraintdef(r.oid, true) as check
FROM
    pg_catalog.pg_constraint r
    JOIN pg_catalog.pg_class ct
      ON r.conrelid = ct.oid
    JOIN pg_catalog.pg_namespace n
      ON ct.relnamespace = n.oid
WHERE
    r.contype = 'c';

CREATE VIEW hdb_catalog.hdb_unique_constraint AS
SELECT
    tc.table_name,
    tc.constraint_schema AS table_schema,
    tc.constraint_name as constraint_name,
    json_agg(kcu.column_name) AS columns
FROM
    information_schema.table_constraints tc
    JOIN information_schema.key_column_usage AS kcu
    USING (constraint_schema, constraint_name)
WHERE
    constraint_type = 'UNIQUE'
GROUP BY
    tc.table_name, tc.constraint_schema, tc.constraint_name;

CREATE VIEW hdb_catalog.hdb_primary_key AS
SELECT
    tc.table_schema,
    tc.table_name,
    tc.constraint_name,
    json_agg(ccu.column_name) as columns
FROM
    information_schema.table_constraints tc
    JOIN information_schema.constraint_column_usage ccu
    ON tc.constraint_name = ccu.constraint_name
WHERE
    constraint_type = 'PRIMARY KEY'
GROUP BY
    tc.table_schema, tc.table_name, tc.constraint_name;

CREATE FUNCTION hdb_catalog.inject_table_defaults(view_schema text, view_name text, tab_schema text, tab_name text) RETURNS void
LANGUAGE plpgsql AS $$
    DECLARE
        r RECORD;
    BEGIN
      FOR r IN SELECT column_name, column_default FROM information_schema.columns WHERE table_schema = tab_schema AND table_name = tab_name AND column_default IS NOT NULL LOOP
          EXECUTE format('ALTER VIEW %I.%I ALTER COLUMN %I SET DEFAULT %s;', view_schema, view_name, r.column_name, r.column_default);
      END LOOP;
    END;
$$;