/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package migrations

import (
	"context"
	"fmt"

	"github.com/apache/answer/internal/base/data"
	"github.com/apache/answer/internal/entity"
	"xorm.io/xorm"
)

const minDBVersion = 0

// Migration describes on migration from lower version to high version
type Migration interface {
	Version() string
	Description() string
	Migrate(ctx context.Context, x *xorm.Engine) error
	ShouldCleanCache() bool
}

type migration struct {
	version          string
	description      string
	migrate          func(ctx context.Context, x *xorm.Engine) error
	shouldCleanCache bool
}

// Version returns the migration's version
func (m *migration) Version() string {
	return m.version
}

// Description returns the migration's description
func (m *migration) Description() string {
	return m.description
}

// Migrate executes the migration
func (m *migration) Migrate(ctx context.Context, x *xorm.Engine) error {
	return m.migrate(ctx, x)
}

// ShouldCleanCache should clean the cache
func (m *migration) ShouldCleanCache() bool {
	return m.shouldCleanCache
}

// NewMigration creates a new migration
func NewMigration(version, desc string, fn func(ctx context.Context, x *xorm.Engine) error, shouldCleanCache bool) Migration {
	return &migration{version: version, description: desc, migrate: fn, shouldCleanCache: shouldCleanCache}
}

// Use noopMigration when there is a migration that has been no-oped
var noopMigration = func(_ context.Context, _ *xorm.Engine) error { return nil }

var migrations = []Migration{
	// 0->1
	NewMigration("v0.0.1", "this is first version, no operation", noopMigration, false),
	NewMigration("v0.3.0", "add user language", addUserLanguage, false),
	NewMigration("v0.4.1", "add recommend and reserved tag fields", addTagRecommendedAndReserved, false),
	NewMigration("v0.5.0", "add activity timeline", addActivityTimeline, false),
	NewMigration("v0.6.0", "add user role", addRoleFeatures, false),
	NewMigration("v1.0.0", "add theme and private mode", addThemeAndPrivateMode, true),
	NewMigration("v1.0.2", "add new answer notification", addNewAnswerNotification, true),
	NewMigration("v1.0.5", "add plugin", addPlugin, false),
	NewMigration("v1.0.7", "add user pin hide features", addRolePinAndHideFeatures, true),
	NewMigration("v1.0.8", "update accept answer rank", updateAcceptAnswerRank, true),
	NewMigration("v1.0.9", "add login limitations", addLoginLimitations, true),
	NewMigration("v1.1.0-beta.1", "update user pin hide features", updateRolePinAndHideFeatures, true),
	NewMigration("v1.1.0-beta.2", "update question post time", updateQuestionPostTime, true),
	NewMigration("v1.1.0", "add gravatar base url", updateCount, true),
	NewMigration("v1.1.1", "update the length of revision content", updateTheLengthOfRevisionContent, false),
	NewMigration("v1.1.2", "add notification config", addNoticeConfig, true),
	NewMigration("v1.1.3", "set default user notification config", setDefaultUserNotificationConfig, false),
	NewMigration("v1.2.0", "add recover answer permission", addRecoverPermission, true),
	NewMigration("v1.2.1", "add password login control", addPasswordLoginControl, true),
	NewMigration("v1.2.5", "add notification plugin and theme config", addNotificationPluginAndThemeConfig, true),
	NewMigration("v1.3.0", "add review", addReview, false),
	NewMigration("v1.3.6", "add hot score to question table", addQuestionHotScore, true),
	NewMigration("v1.4.0", "add badge/badge_group/badge_award table", addBadges, true),
	NewMigration("v1.4.1", "add question link", addQuestionLink, true),
	NewMigration("v1.4.2", "add the number of question links", addQuestionLinkedCount, true),
	NewMigration("v1.4.5", "add file record", addFileRecord, true),
	NewMigration("v1.5.1", "add plugin kv storage", addPluginKVStorage, true),
	NewMigration("v1.6.0", "move user config to interface", moveUserConfigToInterface, true),
}

func GetMigrations() []Migration {
	return migrations
}

// GetCurrentDBVersion returns the current db version
func GetCurrentDBVersion(engine *xorm.Engine) (int64, error) {
	if err := engine.Sync(new(entity.Version)); err != nil {
		return -1, fmt.Errorf("sync version failed: %v", err)
	}

	currentVersion := &entity.Version{ID: 1}
	has, err := engine.Get(currentVersion)
	if err != nil {
		return -1, fmt.Errorf("get first version failed: %v", err)
	}
	if !has {
		_, err := engine.InsertOne(&entity.Version{ID: 1, VersionNumber: 0})
		if err != nil {
			return -1, fmt.Errorf("insert first version failed: %v", err)
		}
		return 0, nil
	}
	return currentVersion.VersionNumber, nil
}

// ExpectedVersion returns the expected db version
func ExpectedVersion() int64 {
	return int64(minDBVersion + len(migrations))
}

// Migrate database to current version
func Migrate(debug bool, dbConf *data.Database, cacheConf *data.CacheConf, upgradeToSpecificVersion string) error {
	cache, cacheCleanup, err := data.NewCache(cacheConf)
	if err != nil {
		fmt.Println("new cache failed:", err.Error())
	}
	engine, err := data.NewDB(debug, dbConf)
	if err != nil {
		fmt.Println("new database failed: ", err.Error())
		return err
	}
	defer engine.Close()

	currentDBVersion, err := GetCurrentDBVersion(engine)
	if err != nil {
		return err
	}
	expectedVersion := ExpectedVersion()
	if len(upgradeToSpecificVersion) > 0 {
		fmt.Printf("[migrate] user set upgrade to version: %s\n", upgradeToSpecificVersion)
		for i, m := range migrations {
			if m.Version() == upgradeToSpecificVersion {
				currentDBVersion = int64(i)
				break
			}
		}
	}

	for currentDBVersion < expectedVersion {
		fmt.Printf("[migrate] current db version is %d, try to migrate version %d, latest version is %d\n",
			currentDBVersion, currentDBVersion+1, expectedVersion)
		migrationFunc := migrations[currentDBVersion]
		fmt.Printf("[migrate] try to migrate Answer version %s, description: %s\n", migrationFunc.Version(), migrationFunc.Description())
		if err := migrationFunc.Migrate(context.Background(), engine); err != nil {
			fmt.Printf("[migrate] migrate to db version %d failed: %s\n", currentDBVersion+1, err.Error())
			return err
		}
		if migrationFunc.ShouldCleanCache() {
			if err := cache.Flush(context.Background()); err != nil {
				fmt.Printf("[migrate] flush cache failed: %s\n", err.Error())
			}
		}
		fmt.Printf("[migrate] migrate to db version %d success\n", currentDBVersion+1)
		if _, err := engine.Update(&entity.Version{ID: 1, VersionNumber: currentDBVersion + 1}); err != nil {
			fmt.Printf("[migrate] migrate to db version %d, update failed: %s", currentDBVersion+1, err.Error())
			return err
		}
		currentDBVersion++
	}
	if cache != nil {
		cacheCleanup()
	}
	return nil
}
