#!/usr/bin/env bash
# deepdive-create -- Creates a table/view in the database
#
# > deepdive create table TABLE
# Creates a table as defined in app.ddlog or schema.json.
#
# > deepdive create table TABLE as SELECT_QUERY
# > deepdive create view  TABLE as SELECT_QUERY
# Creates a table or view named TABLE with the result of given SELECT query,
# dropping existing table or view with the same name.
#
# > deepdive create table TABLE [COLUMN:TYPE[:CONSTRAINT]]...
# Creates a new table named TABLE with given column definitions.
#
# > deepdive create table TABLE like ANOTHER_TABLE
# Creates a new table named TABLE after the schema of ANOTHER_TABLE.
#
# > deepdive create table-if-not-exists TABLE [...]
# Creates table if it does not exists already.
#
# > deepdive create SPECIAL_TYPE table TABLE ...
# > deepdive create SPECIAL_TYPE view  TABLE ...
# Creates a SPECIAL_TYPE table/view, such as "GLOBAL UNLOGGED" table or
# "MATERIALIZED" view.
##
set -euo pipefail

# parse database settings and load the driver
. load-db-driver.sh

[[ $# -gt 0 ]] || usage "$0" "What to create (table or view) must be given"
What=$1; shift

[[ $# -gt 0 ]] || usage "$0" "Missing TABLE name"
Table=$1; shift
# TODO double quote table names and column names?

case $What in
    table)
        if [[ $# -eq 0 ]]; then
            DEEPDIVE_APP=$(find-deepdive-app)
            app-has-been-compiled
            sql=$(schema_json_to_sql "$DEEPDIVE_APP"/run/compiled/schema.json "$Table") ||
                error "$Table: No such table defined in schema"
            exec db-execute "$sql"
        else
            # show warning if the table exists in app schema
            if DEEPDIVE_APP=$(find-deepdive-app) &&
                    app-has-been-compiled &>/dev/null &&
                    sql=$(schema_json_to_sql "$DEEPDIVE_APP"/run/compiled/schema.json "$Table"); then
                warning "$Table: Already defined in schema, overriding its definition"
            fi
            # create table from given definition
            case $1 in
                as) # create as query
                    [[ $# -gt 1 ]] || usage "$0" "Missing SELECT_QUERY"
                    Query=$2
                    exec db-create-table-as "$Table" "$Query"
                    ;;

                like) # create like another table
                    [[ $# -gt 1 ]] || usage "$0" "Missing ANOTHER_TABLE name"
                    AnotherTable=$2
                    exec db-create-table-like "$Table" "$AnotherTable"
                    ;;

                *) # create table from column definitions
                    exec db-create-table-def "$Table" "$@"
            esac
        fi
        ;;

    view)
        [[ $# -gt 1 && $1 = "as" ]] || usage "$0" "SELECT_QUERY for the view must be specified, followed by 'as'"
        Query=$2
        exec db-create-view-as "$Table" "$Query"
        ;;

    # recognize table-if-not-exists
    table-if-not-exists)
        CREATE_IF_NOT_EXISTS=1 exec "$0" "${What%-if-not-exists}" "$Table" "$@"
        ;;

    *)
        # recognize the table/view type modifier that precedes them
        case $Table in
            table)
                CREATE_TABLE_TYPE="$What" exec "$0" "$Table" "$@"
                ;;
            view)
                CREATE_VIEW_TYPE="$What" exec "$0" "$Table" "$@"
                ;;

            *)
                error "$What cannot be created: Only 'table' or 'view' can be created"
        esac
esac