// Copyright (C) 2019 Marius Schellenberger

package db

import (
	"git.giftfish.de/ston1th/docstore/pkg/log"
	"git.giftfish.de/ston1th/docstore/pkg/store"
)

const (
	versionKey     = "version/version"
	currentVersion = 2
)

type migrator func(*DB, int) error

var migrators = []migrator{
	func(_ *DB, _ int) error {
		return nil
	},
	func(_ *DB, _ int) error {
		// dummy placeholder
		return nil
	},
	func(db *DB, _ int) (err error) {
		err = db.addDefaultTags()
		if err != nil {
			return
		}
		return db.RetagAll()
	},
}

func (db *DB) runMigrations() (err error) {
	var version int
	err = db.store.Get(versionKey, &version)
	if err == store.ErrKeyNotFound {
		err = db.store.Set(versionKey, currentVersion)
		if err != nil {
			return
		}
		err = db.store.Get(versionKey, &version)
		if err != nil {
			return
		}
	}
	log.Printf("db: database version %d", version)
	for version < currentVersion {
		v := version + 1
		log.Printf("db: running migration version %d", v)
		err = migrators[v](db, v)
		if err != nil {
			return
		}
		err = db.store.Set(versionKey, v)
		if err != nil {
			return
		}
		version = v
		log.Printf("db: database version %d", version)
	}
	return
}