package main

import (
	"context"
	"flag"
	"fmt"
	"os"
	"strings"

	"github.com/gochat/gochat/internal/app"
	"github.com/gochat/gochat/internal/config"
	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/repository"
	"github.com/gochat/gochat/internal/search"
	applogger "github.com/gochat/gochat/pkg/logger"
	"gorm.io/gorm"
)

func main() {
	var accountID uint
	var batchSize int
	var types string
	var bootstrap bool
	flag.UintVar(&accountID, "account", 0, "account ID to reindex; 0 means all accounts")
	flag.IntVar(&batchSize, "batch", 500, "documents per indexing batch")
	flag.StringVar(&types, "types", "all", "comma-separated types: conversation,message,contact,company,article,help_center,all")
	flag.BoolVar(&bootstrap, "bootstrap", true, "create/update Meilisearch indexes and settings before indexing")
	flag.Parse()

	if batchSize < 1 {
		fmt.Fprintln(os.Stderr, "batch must be >= 1")
		os.Exit(1)
	}

	cfg, err := config.Load()
	if err != nil {
		fmt.Fprintf(os.Stderr, "config load: %v\n", err)
		os.Exit(1)
	}
	if err := validateSearchEngineForReindex(cfg.Search); err != nil {
		fmt.Fprintf(os.Stderr, "search config: %v\n", err)
		os.Exit(1)
	}
	_ = applogger.Init(applogger.Config{Level: cfg.Log.Level, Format: cfg.Log.Format, Output: "stdout", ErrorOutput: "stderr"})

	db, err := app.NewDatabase(&cfg.Database, cfg.Log.Level)
	if err != nil {
		fmt.Fprintf(os.Stderr, "database: %v\n", err)
		os.Exit(1)
	}

	searchRepo := repository.NewSearchRepo(db)
	engine, err := search.NewSearchEngine(search.EngineConfig{
		Engine:         cfg.Search.Engine,
		Host:           cfg.Search.Host,
		APIKey:         cfg.Search.APIKey,
		IndexPrefix:    cfg.Search.IndexPrefix,
		TimeoutSeconds: cfg.Search.TimeoutSeconds,
	}, searchRepo)
	if err != nil {
		fmt.Fprintf(os.Stderr, "search engine: %v\n", err)
		os.Exit(1)
	}

	ctx := context.Background()
	if bootstrap {
		if err := engine.Bootstrap(ctx); err != nil {
			fmt.Fprintf(os.Stderr, "bootstrap search indexes: %v\n", err)
			os.Exit(1)
		}
	}

	selected := parseTypes(types)
	stats := map[search.SearchResultType]int{}
	if selected[search.ResultTypeConversation] {
		stats[search.ResultTypeConversation], err = reindexConversations(ctx, engine, db, accountID, batchSize)
		fatalIf(err)
	}
	if selected[search.ResultTypeMessage] {
		stats[search.ResultTypeMessage], err = reindexMessages(ctx, engine, db, accountID, batchSize)
		fatalIf(err)
	}
	if selected[search.ResultTypeContact] {
		stats[search.ResultTypeContact], err = reindexContacts(ctx, engine, db, accountID, batchSize)
		fatalIf(err)
	}
	if selected[search.ResultTypeCompany] {
		stats[search.ResultTypeCompany], err = reindexCompanies(ctx, engine, db, accountID, batchSize)
		fatalIf(err)
	}
	if selected[search.ResultTypeArticle] || selected[search.ResultTypeHelpCenter] {
		stats[search.ResultTypeArticle], err = reindexArticles(ctx, engine, db, accountID, batchSize)
		fatalIf(err)
	}

	fmt.Println("Search reindex complete")
	for docType, count := range stats {
		fmt.Printf("%s: %d\n", docType, count)
	}
}

func validateSearchEngineForReindex(cfg config.SearchConfig) error {
	if strings.ToLower(strings.TrimSpace(cfg.Engine)) != search.EngineMeilisearch {
		return fmt.Errorf("reindex_search requires search.engine=meilisearch; db fallback does not index documents")
	}
	return nil
}

func parseTypes(raw string) map[search.SearchResultType]bool {
	selected := map[search.SearchResultType]bool{}
	for _, part := range strings.Split(raw, ",") {
		switch search.SearchResultType(strings.TrimSpace(part)) {
		case "", "all":
			selected[search.ResultTypeConversation] = true
			selected[search.ResultTypeMessage] = true
			selected[search.ResultTypeContact] = true
			selected[search.ResultTypeCompany] = true
			selected[search.ResultTypeArticle] = true
			selected[search.ResultTypeHelpCenter] = true
		case search.ResultTypeConversation:
			selected[search.ResultTypeConversation] = true
		case search.ResultTypeMessage:
			selected[search.ResultTypeMessage] = true
		case search.ResultTypeContact:
			selected[search.ResultTypeContact] = true
		case search.ResultTypeCompany:
			selected[search.ResultTypeCompany] = true
		case search.ResultTypeArticle:
			selected[search.ResultTypeArticle] = true
		case search.ResultTypeHelpCenter:
			selected[search.ResultTypeHelpCenter] = true
		}
	}
	return selected
}

func reindexConversations(ctx context.Context, engine search.SearchEngine, db *gorm.DB, accountID uint, batchSize int) (int, error) {
	var count int
	var lastID uint
	for {
		var rows []model.Conversation
		q := db.WithContext(ctx).Where("id > ?", lastID).Order("id ASC").Limit(batchSize)
		if accountID != 0 {
			q = q.Where("account_id = ?", accountID)
		}
		if err := q.Find(&rows).Error; err != nil {
			return count, err
		}
		if len(rows) == 0 {
			return count, nil
		}
		docs := make([]search.SearchDocument, 0, len(rows))
		for _, row := range rows {
			docs = append(docs, search.ConversationDocument(row))
			lastID = row.ID
		}
		if err := engine.IndexBatch(ctx, docs); err != nil {
			return count, err
		}
		count += len(rows)
	}
}

func reindexMessages(ctx context.Context, engine search.SearchEngine, db *gorm.DB, accountID uint, batchSize int) (int, error) {
	var count int
	var lastID uint
	for {
		var rows []model.Message
		q := db.WithContext(ctx).Where("id > ?", lastID).Order("id ASC").Limit(batchSize)
		if accountID != 0 {
			q = q.Where("account_id = ?", accountID)
		}
		if err := q.Find(&rows).Error; err != nil {
			return count, err
		}
		if len(rows) == 0 {
			return count, nil
		}
		docs := make([]search.SearchDocument, 0, len(rows))
		for _, row := range rows {
			docs = append(docs, search.MessageDocument(row))
			lastID = row.ID
		}
		if err := engine.IndexBatch(ctx, docs); err != nil {
			return count, err
		}
		count += len(rows)
	}
}

func reindexContacts(ctx context.Context, engine search.SearchEngine, db *gorm.DB, accountID uint, batchSize int) (int, error) {
	var count int
	var lastID uint
	for {
		var rows []model.Contact
		q := db.WithContext(ctx).Where("id > ?", lastID).Order("id ASC").Limit(batchSize)
		if accountID != 0 {
			q = q.Where("account_id = ?", accountID)
		}
		if err := q.Find(&rows).Error; err != nil {
			return count, err
		}
		if len(rows) == 0 {
			return count, nil
		}
		docs := make([]search.SearchDocument, 0, len(rows))
		for _, row := range rows {
			docs = append(docs, search.ContactDocument(row))
			lastID = row.ID
		}
		if err := engine.IndexBatch(ctx, docs); err != nil {
			return count, err
		}
		count += len(rows)
	}
}

func reindexCompanies(ctx context.Context, engine search.SearchEngine, db *gorm.DB, accountID uint, batchSize int) (int, error) {
	var count int
	var lastID uint
	for {
		var rows []model.Company
		q := db.WithContext(ctx).Where("id > ?", lastID).Order("id ASC").Limit(batchSize)
		if accountID != 0 {
			q = q.Where("account_id = ?", accountID)
		}
		if err := q.Find(&rows).Error; err != nil {
			return count, err
		}
		if len(rows) == 0 {
			return count, nil
		}
		docs := make([]search.SearchDocument, 0, len(rows))
		for _, row := range rows {
			docs = append(docs, search.CompanyDocument(row))
			lastID = row.ID
		}
		if err := engine.IndexBatch(ctx, docs); err != nil {
			return count, err
		}
		count += len(rows)
	}
}

func reindexArticles(ctx context.Context, engine search.SearchEngine, db *gorm.DB, accountID uint, batchSize int) (int, error) {
	var count int
	var lastID uint
	for {
		var rows []model.Article
		q := db.WithContext(ctx).Where("id > ?", lastID).Order("id ASC").Limit(batchSize)
		if accountID != 0 {
			q = q.Where("account_id = ?", accountID)
		}
		if err := q.Find(&rows).Error; err != nil {
			return count, err
		}
		if len(rows) == 0 {
			return count, nil
		}
		docs := make([]search.SearchDocument, 0, len(rows))
		for _, row := range rows {
			docs = append(docs, search.ArticleDocument(row))
			lastID = row.ID
		}
		if err := engine.IndexBatch(ctx, docs); err != nil {
			return count, err
		}
		count += len(rows)
	}
}

func fatalIf(err error) {
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}
}