package mongo

import (
	"context"
	"errors"
	"os"
	"strings"
	"time"

	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	"go.mongodb.org/mongo-driver/mongo/readpref"
)

var (
	mongo_uri      string
	mongo_database string
	mongo_username string
	mongo_password string
)

func init() {
	mongo_uri = os.Getenv("MONGO_URI")
	if mongo_uri == "" {
		mongo_uri = "mongodb://localhost:27017"
	}
	mongo_database = os.Getenv("MONGO_DB")
	if mongo_database == "" {
		mongo_database = "admin"
	}
	mongo_username = os.Getenv("MONGO_USERNAME")
	mongo_password = os.Getenv("MONGO_PASSWORD")
}

// 新连接获取
func newConnect() (*mongo.Client, error) {
	clientOpts := options.Client().ApplyURI(mongo_uri).SetConnectTimeout(3 * time.Second)

	if mongo_username != "" && mongo_password != "" {
		clientOpts = clientOpts.SetAuth(options.Credential{
			AuthMechanism: "SCRAM-SHA-256",
			AuthSource:    "admin",
			Username:      mongo_username,
			Password:      mongo_password,
		})
	}

	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()

	return mongo.Connect(ctx, clientOpts)
}

func newDB(client *mongo.Client, dbname string) (*mongo.Database, error) {
	db := dbname
	if db == "" {
		db = mongo_database
	}

	return client.Database(db), nil
}

func newCollection(client *mongo.Client, dbname, colname string) (*mongo.Collection, error) {
	db, err := newDB(client, dbname)
	if err != nil {
		return nil, err
	}
	return db.Collection(colname), nil
}

// 获取默认集合，即数据库名已指定的库
func newDefaultCollection(client *mongo.Client, colname string) (*mongo.Collection, error) {
	db, err := newDB(client, "")
	if err != nil {
		return nil, err
	}
	return db.Collection(colname), nil
}

func ping() error {
	client, err := newConnect()
	if err != nil {
		return err
	}
	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
	defer cancel()
	defer client.Disconnect(ctx)
	return client.Ping(ctx, readpref.Primary())
}

// Collection 获取集合
func Collection(client *mongo.Client, cname string) (*mongo.Collection, error) {
	collection := client.Database(mongo_database).Collection(cname)
	return collection, nil
}

// CollectionMulti 支持多数据库直接获取collection
func CollectionMulti(client *mongo.Client, cname string) (*mongo.Collection, error) {
	name := strings.Split(cname, ".")
	if len(name) != 2 {
		return nil, errors.New("collection名称不正确，请使用[database.collection]方式使用")
	}
	if name[0] == "" || name[1] == "" {
		return nil, errors.New("名称不能为空")
	}

	collection := client.Database(name[0]).Collection(name[1])
	return collection, nil
}