package db

import (
	_ "embed"
	"fmt"
	"strings"

	"github.com/jmoiron/sqlx"
	"github.com/spf13/viper"
)

// srrdbSchema is the DDL of the srrdb database. Keeping it in a file lets the
// schema be read and edited without touching Go code; go:embed pulls it into the
// binary at build time.
//
//go:embed srrdb.sql
var srrdbSchema string

// NewSrrdb opens the separate SQLite database that holds srrdb_releases.
// The driver name is read from db.ext.driver (sqlite, modernc.org/sqlite), so
// the driver can be replaced in configuration without touching this file.
func NewSrrdb() *sqlx.DB {
	driver := viper.GetString("db.ext.driver")
	path := viper.GetString("srrdb.database")

	db, err := sqlx.Connect(driver, path)
	if err != nil {
		panic("Failed to connect to the srrdb database: " + err.Error())
	}

	if err = db.Ping(); err != nil {
		panic("Failed to ping the srrdb database: " + err.Error())
	}

	if err = srrdbCreate(db); err != nil {
		panic("Failed to create the srrdb schema: " + err.Error())
	}

	return db
}

// srrdbCreate applies the embedded DDL statement by statement. Every statement is
// written to be repeatable, so an existing database is left alone: this creates
// missing objects, it does not alter existing ones.
//
// Splitting on ";" is safe for this schema because no statement holds a semicolon
// inside a literal.
func srrdbCreate(db *sqlx.DB) error {
	for _, statement := range strings.Split(srrdbSchema, ";") {
		if statement = strings.TrimSpace(statement); statement == "" {
			continue
		}

		if _, err := db.Exec(statement); err != nil {
			return fmt.Errorf("apply srrdb schema statement %q: %w", statement, err)
		}
	}

	return nil
}