package sqlc

import (
	"context"
)

// BackendType is an enum that represents the type of database backend we're
// using.
type BackendType uint8

const (
	// BackendTypeUnknown indicates we're using an unknown backend.
	BackendTypeUnknown BackendType = iota

	// BackendTypeSqlite indicates we're using a SQLite backend.
	BackendTypeSqlite

	// BackendTypePostgres indicates we're using a Postgres backend.
	BackendTypePostgres
)

// wrappedTX is a wrapper around a DBTX that also stores the database backend
// type.
type wrappedTX struct {
	DBTX

	backendType BackendType
}

// Backend returns the type of database backend we're using.
func (q *Queries) Backend() BackendType {
	wtx, ok := q.db.(*wrappedTX)
	if !ok {
		// Shouldn't happen unless a new database backend type is added
		// but not initialized correctly.
		return BackendTypeUnknown
	}

	return wtx.backendType
}

// NewSqlite creates a new Queries instance for a SQLite database.
func NewSqlite(db DBTX) *Queries {
	return &Queries{db: &wrappedTX{db, BackendTypeSqlite}}
}

// NewPostgres creates a new Queries instance for a Postgres database.
func NewPostgres(db DBTX) *Queries {
	return &Queries{db: &wrappedTX{db, BackendTypePostgres}}
}

// CustomQueries defines a set of custom queries that we define in addition
// to the ones generated by sqlc.
type CustomQueries interface {
	// CountActions returns the number of actions that match the provided
	// ActionQueryParams.
	CountActions(ctx context.Context, arg ActionQueryParams) (int64, error)

	// ListActions retrieves a list of actions based on the provided
	// ListActionsParams.
	ListActions(ctx context.Context,
		arg ListActionsParams) ([]Action, error)

	// Backend returns the type of the database backend used.
	Backend() BackendType
}