package data

import (
	"context"
	"fmt"
	"log"
	"sync"
	"time"

	"github.com/google/wire"
	"github.com/redis/go-redis/v9"
	"gorm.io/gorm"
	"kra/internal/conf"
)

var ProviderSet = wire.NewSet(NewData, NewSystemRepo, NewAccessRepo, NewMenuRepo, NewOrganizationRepo, NewSettingsRepo, NewVersionRepo, NewExportRepo, NewAuditRepo, NewTaskRepo, NewMediaRepo, NewAnnouncementRepo, NewEmailRepo, NewCache, NewFileStorage)

type Data struct {
	mu       sync.RWMutex
	initMu   sync.Mutex
	gormDB   *gorm.DB
	redis    *redis.Client
	database *conf.Data_Database
	config   *conf.Data
	admin    *conf.AdminBackend
	storage  *reloadableStorage
}

func NewData(c *conf.Data, admin *conf.AdminBackend) (*Data, func(), error) {
	if c == nil || c.Database == nil {
		return nil, nil, fmt.Errorf("database configuration is required")
	}
	d := &Data{database: c.Database, config: c, admin: admin}
	db, err := openDatabase(c.Database, false, "")
	usingFallback := false
	if err != nil {
		// The initialization endpoint must remain available when the configured
		// target database has not been created yet.
		log.Printf("configured database unavailable before initialization: %v", err)
		db, err = openFallbackDatabase()
		if err != nil {
			return nil, nil, fmt.Errorf("open bootstrap database: %w", err)
		}
		usingFallback = true
	}
	d.gormDB = db
	if !usingFallback {
		if err = migrateAll(db); err != nil {
			return nil, nil, fmt.Errorf("migrate tables: %w", err)
		}
	}
	if candidate := openRedis(c.Redis); candidate != nil {
		d.redis = candidate
	}
	cleanup := func() {
		d.mu.RLock()
		db := d.gormDB
		d.mu.RUnlock()
		if sqlDB, closeErr := db.DB(); closeErr == nil {
			_ = sqlDB.Close()
		}
		if d.redis != nil {
			_ = d.redis.Close()
		}
	}
	return d, cleanup, nil
}

func openRedis(config *conf.Data_Redis) *redis.Client {
	if config == nil || config.Addr == "" {
		return nil
	}
	options := &redis.Options{Addr: config.Addr, Network: config.Network}
	if config.ReadTimeout != nil {
		options.ReadTimeout = config.ReadTimeout.AsDuration()
	}
	if config.WriteTimeout != nil {
		options.WriteTimeout = config.WriteTimeout.AsDuration()
	}
	candidate := redis.NewClient(options)
	pingCtx, cancel := context.WithTimeout(context.Background(), 800*time.Millisecond)
	defer cancel()
	if err := candidate.Ping(pingCtx).Err(); err != nil {
		log.Printf("redis unavailable, using in-memory cache: %v", err)
		_ = candidate.Close()
		return nil
	}
	return candidate
}

func (d *Data) activateDatabase(db *gorm.DB, config *conf.Data_Database) {
	d.mu.Lock()
	old := d.gormDB
	d.gormDB = db
	d.database = config
	d.config.Database = config
	d.mu.Unlock()
	if old != nil {
		if sqlDB, e := old.DB(); e == nil {
			_ = sqlDB.Close()
		}
	}
}