#!/bin/sh

# Copyright (C) 2018-2023 Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# shellcheck disable=SC1091
# SC1091: Not following: ... was not specified as input (see shellcheck -x).

# Exit with error if commands exit with non-zero and if undefined variables are
# used.
set -eu

# shellcheck disable=SC2034
# SC2034: ... appears unused. Verify use (or export if used externally).
prefix="/usr"

# Include utilities. Use installed version if available and
# use build version if it isn't.
if test -f "${prefix}/share/kea/scripts/admin-utils.sh"; then
    . "${prefix}/share/kea/scripts/admin-utils.sh"
else
    . "/build/kea/src/kea-2.4.0/src/bin/admin/admin-utils.sh"
fi

VERSION=$(pgsql_version "$@")

if [ "$VERSION" != "3.3" ]; then
    printf 'This script upgrades 3.3 to 4.0. '
    printf 'Reported version is %s. Skipping upgrade.\n' "${VERSION}"
    exit 0
fi

psql "$@" >/dev/null <<EOF
START TRANSACTION;

-- This line starts the schema upgrade to version 4.0.

-- Add a column holding hosts for user context.
ALTER TABLE hosts ADD COLUMN user_context TEXT;

-- Add a column holding DHCP options for user context.
ALTER TABLE dhcp4_options ADD COLUMN user_context TEXT;
ALTER TABLE dhcp6_options ADD COLUMN user_context TEXT;

-- Create index for searching leases by subnet identifier.
CREATE INDEX lease4_by_subnet_id ON lease4 (subnet_id);

-- Create for searching leases by subnet identifier and lease type.
CREATE INDEX lease6_by_subnet_id_lease_type ON lease6 (subnet_id, lease_type);

-- The index by iaid_subnet_id_duid is not the best choice because there are
-- cases when we don't specify subnet identifier while searching leases. The
-- index will be universal if the subnet_id is the right most column in the
-- index.
DROP INDEX lease6_by_iaid_subnet_id_duid;
CREATE INDEX lease6_by_duid_iaid_subnet_id ON lease6 (duid, iaid, subnet_id);

-- Create v4 lease statistics table
CREATE TABLE lease4_stat (
    subnet_id BIGINT NOT NULL,
    state INT8 NOT NULL,
    leases BIGINT,
    PRIMARY KEY (subnet_id, state)
);

--
-- Create v4 insert trigger procedure
CREATE FUNCTION proc_stat_lease4_insert () RETURNS trigger AS \$stat_lease4_insert\$
BEGIN
    IF NEW.state < 2 THEN
        UPDATE lease4_stat
            SET leases = leases + 1
            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;

        IF NOT FOUND THEN
            INSERT INTO lease4_stat VALUES (new.subnet_id, new.state, 1);
        END IF;
    END IF;

    -- Return is ignored since this is an after insert
    RETURN NULL;
END;
\$stat_lease4_insert\$ LANGUAGE plpgsql;

-- Create v4 insert trigger procedure
CREATE TRIGGER stat_lease4_insert
AFTER INSERT ON lease4
    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_insert();

--
-- Create v4 update trigger procedure
CREATE FUNCTION proc_stat_lease4_update () RETURNS trigger AS \$stat_lease4_update\$
BEGIN
    IF OLD.state != NEW.state THEN
        IF OLD.state < 2 THEN
            -- Decrement the old state count if record exists
            UPDATE lease4_stat SET leases = leases - 1
            WHERE subnet_id = OLD.subnet_id AND state = OLD.state;
        END IF;

        IF NEW.state < 2 THEN
            -- Increment the new state count if record exists
            UPDATE lease4_stat SET leases = leases + 1
            WHERE subnet_id = NEW.subnet_id AND state = NEW.state;

            -- Insert new state record if it does not exist
            IF NOT FOUND THEN
                INSERT INTO lease4_stat VALUES (NEW.subnet_id, NEW.state, 1);
            END IF;
        END IF;
    END IF;

    -- Return is ignored since this is an after insert
    RETURN NULL;
END;
\$stat_lease4_update\$ LANGUAGE plpgsql;

-- Create v4 update trigger
CREATE TRIGGER stat_lease4_update
AFTER UPDATE ON lease4
    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_update();

--
-- Create the v4 delete trigger procedure
CREATE FUNCTION proc_stat_lease4_delete () RETURNS trigger AS \$stat_lease4_delete\$
BEGIN
    IF OLD.state < 2 THEN
        -- Decrement the state count if record exists
        UPDATE lease4_stat SET leases = leases - 1
        WHERE subnet_id = OLD.subnet_id AND OLD.state = state;
    END IF;

    -- Return is ignored since this is an after insert
    RETURN NULL;
END;
\$stat_lease4_delete\$ LANGUAGE plpgsql;

-- Create the v4 delete trigger
CREATE TRIGGER stat_lease4_delete
AFTER DELETE ON lease4
    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease4_delete();

-- Create v6 lease statistics table
CREATE TABLE lease6_stat (
    subnet_id BIGINT NOT NULL,
    lease_type SMALLINT NOT NULL,
    state INT8 NOT NULL,
    leases BIGINT,
    PRIMARY KEY (subnet_id, lease_type, state)
);

--
-- Create v6 insert trigger procedure
CREATE FUNCTION proc_stat_lease6_insert () RETURNS trigger AS \$stat_lease6_insert\$
BEGIN
    IF NEW.state < 2 THEN
        UPDATE lease6_stat
        SET leases = leases + 1
        WHERE
        subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
        AND state = NEW.state;

        IF NOT FOUND THEN
            INSERT INTO lease6_stat
            VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
        END IF;
    END IF;

    -- Return is ignored since this is an after insert
    RETURN NULL;
END;
\$stat_lease6_insert\$ LANGUAGE plpgsql;

-- Create v6 insert trigger procedure
CREATE TRIGGER stat_lease6_insert
AFTER INSERT ON lease6
    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_insert();

--
-- Create v6 update trigger procedure
CREATE FUNCTION proc_stat_lease6_update () RETURNS trigger AS \$stat_lease6_update\$
BEGIN
    IF OLD.state != NEW.state THEN
        IF OLD.state < 2 THEN
            -- Decrement the old state count if record exists
            UPDATE lease6_stat SET leases = leases - 1
            WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
            AND state = OLD.state;
        END IF;

        IF NEW.state < 2 THEN
            -- Increment the new state count if record exists
            UPDATE lease6_stat SET leases = leases + 1
            WHERE subnet_id = NEW.subnet_id AND lease_type = NEW.lease_type
            AND state = NEW.state;

            -- Insert new state record if it does not exist
            IF NOT FOUND THEN
                INSERT INTO lease6_stat VALUES (NEW.subnet_id, NEW.lease_type, NEW.state, 1);
            END IF;
        END IF;
    END IF;

    -- Return is ignored since this is an after insert
    RETURN NULL;
END;
\$stat_lease6_update\$ LANGUAGE plpgsql;

-- Create v6 update trigger
CREATE TRIGGER stat_lease6_update
AFTER UPDATE ON lease6
    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_update();

--
-- Create the v6 delete trigger procedure
CREATE FUNCTION proc_stat_lease6_delete() RETURNS trigger AS \$stat_lease6_delete\$
BEGIN
    IF OLD.state < 2 THEN
        -- Decrement the state count if record exists
        UPDATE lease6_stat SET leases = leases - 1
        WHERE subnet_id = OLD.subnet_id AND lease_type = OLD.lease_type
        AND OLD.state = state;
    END IF;

    -- Return is ignored since this is an after insert
    RETURN NULL;
END;
\$stat_lease6_delete\$ LANGUAGE plpgsql;

-- Create the v6 delete trigger
CREATE TRIGGER stat_lease6_delete
AFTER DELETE ON lease6
    FOR EACH ROW EXECUTE PROCEDURE proc_stat_lease6_delete();

-- Populate lease4_stat table based on existing leases
-- We only care about assigned and declined states
INSERT INTO lease4_stat (subnet_id, state, leases)
    SELECT subnet_id, state, count(state)
    FROM lease4 WHERE state < 2
    GROUP BY subnet_id, state ORDER BY subnet_id;

-- Populate lease6_stat table based on existing leases
-- We only care about assigned and declined states
INSERT INTO lease6_stat (subnet_id, lease_type, state, leases)
    SELECT subnet_id, lease_type, state, count(state)
    FROM lease6 WHERE state < 2
    GROUP BY subnet_id, lease_type, state
    ORDER BY subnet_id;

-- Update the schema version number.
UPDATE schema_version
    SET version = '4', minor = '0';

-- This line concludes the schema upgrade to version 4.0.

-- Commit the script transaction.
COMMIT;

EOF
