// Copyright 2016 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.

package code

import (
	"context"
	"os"
	"strconv"
	"strings"
	"time"

	"code.gitea.io/gitea/models"
	"code.gitea.io/gitea/modules/graceful"
	"code.gitea.io/gitea/modules/log"
	"code.gitea.io/gitea/modules/setting"
	"code.gitea.io/gitea/modules/timeutil"
)

// SearchResult result of performing a search in a repo
type SearchResult struct {
	RepoID      int64
	StartIndex  int
	EndIndex    int
	Filename    string
	Content     string
	CommitID    string
	UpdatedUnix timeutil.TimeStamp
	Language    string
	Color       string
}

// SearchResultLanguages result of top languages count in search results
type SearchResultLanguages struct {
	Language string
	Color    string
	Count    int
}

// Indexer defines an interface to indexer issues contents
type Indexer interface {
	Index(repo *models.Repository, sha string, changes *repoChanges) error
	Delete(repoID int64) error
	Search(repoIDs []int64, language, keyword string, page, pageSize int) (int64, []*SearchResult, []*SearchResultLanguages, error)
	Close()
}

func filenameIndexerID(repoID int64, filename string) string {
	return indexerID(repoID) + "_" + filename
}

func parseIndexerID(indexerID string) (int64, string) {
	index := strings.IndexByte(indexerID, '_')
	if index == -1 {
		log.Error("Unexpected ID in repo indexer: %s", indexerID)
	}
	repoID, _ := strconv.ParseInt(indexerID[:index], 10, 64)
	return repoID, indexerID[index+1:]
}

func filenameOfIndexerID(indexerID string) string {
	index := strings.IndexByte(indexerID, '_')
	if index == -1 {
		log.Error("Unexpected ID in repo indexer: %s", indexerID)
	}
	return indexerID[index+1:]
}

// Init initialize the repo indexer
func Init() {
	if !setting.Indexer.RepoIndexerEnabled {
		indexer.Close()
		return
	}

	initQueue(setting.Indexer.UpdateQueueLength)

	ctx, cancel := context.WithCancel(context.Background())

	graceful.GetManager().RunAtTerminate(ctx, func() {
		log.Debug("Closing repository indexer")
		indexer.Close()
		log.Info("PID: %d Repository Indexer closed", os.Getpid())
	})

	waitChannel := make(chan time.Duration)
	go func() {
		start := time.Now()
		var (
			rIndexer Indexer
			populate bool
			err      error
		)
		switch setting.Indexer.RepoType {
		case "bleve":
			log.Info("PID: %d Initializing Repository Indexer at: %s", os.Getpid(), setting.Indexer.RepoPath)
			defer func() {
				if err := recover(); err != nil {
					log.Error("PANIC whilst initializing repository indexer: %v\nStacktrace: %s", err, log.Stack(2))
					log.Error("The indexer files are likely corrupted and may need to be deleted")
					log.Error("You can completely remove the \"%s\" directory to make Gitea recreate the indexes", setting.Indexer.RepoPath)
				}
			}()

			rIndexer, populate, err = NewBleveIndexer(setting.Indexer.RepoPath)
			if err != nil {
				if rIndexer != nil {
					rIndexer.Close()
				}
				cancel()
				indexer.Close()
				close(waitChannel)
				log.Fatal("PID: %d Unable to initialize the bleve Repository Indexer at path: %s Error: %v", os.Getpid(), setting.Indexer.RepoPath, err)
			}
		case "elasticsearch":
			log.Info("PID: %d Initializing Repository Indexer at: %s", os.Getpid(), setting.Indexer.RepoConnStr)
			defer func() {
				if err := recover(); err != nil {
					log.Error("PANIC whilst initializing repository indexer: %v\nStacktrace: %s", err, log.Stack(2))
					log.Error("The indexer files are likely corrupted and may need to be deleted")
					log.Error("You can completely remove the \"%s\" index to make Gitea recreate the indexes", setting.Indexer.RepoConnStr)
				}
			}()

			rIndexer, populate, err = NewElasticSearchIndexer(setting.Indexer.RepoConnStr, setting.Indexer.RepoIndexerName)
			if err != nil {
				if rIndexer != nil {
					rIndexer.Close()
				}
				cancel()
				indexer.Close()
				close(waitChannel)
				log.Fatal("PID: %d Unable to initialize the elasticsearch Repository Indexer connstr: %s Error: %v", os.Getpid(), setting.Indexer.RepoConnStr, err)
			}
		default:
			log.Fatal("PID: %d Unknown Indexer type: %s", os.Getpid(), setting.Indexer.RepoType)
		}

		indexer.set(rIndexer)

		go processRepoIndexerOperationQueue(indexer)

		if populate {
			go populateRepoIndexer()
		}
		select {
		case waitChannel <- time.Since(start):
		case <-graceful.GetManager().IsShutdown():
		}

		close(waitChannel)
	}()

	if setting.Indexer.StartupTimeout > 0 {
		go func() {
			timeout := setting.Indexer.StartupTimeout
			if graceful.GetManager().IsChild() && setting.GracefulHammerTime > 0 {
				timeout += setting.GracefulHammerTime
			}
			select {
			case <-graceful.GetManager().IsShutdown():
				log.Warn("Shutdown before Repository Indexer completed initialization")
				cancel()
				indexer.Close()
			case duration, ok := <-waitChannel:
				if !ok {
					log.Warn("Repository Indexer Initialization failed")
					cancel()
					indexer.Close()
					return
				}
				log.Info("Repository Indexer Initialization took %v", duration)
			case <-time.After(timeout):
				cancel()
				indexer.Close()
				log.Fatal("Repository Indexer Initialization Timed-Out after: %v", timeout)
			}
		}()
	}
}