synchronizator-go/pkg/synchronizator.go

package synchronizator

import (
	sql "database/sql"
	"encoding/json"
	"fmt"
	"os"
	"reflect"
	"strings"
	"time"
)

var DefaultOptions = &Options{
	Logger:                  os.Stdout,
	Log_level:               INFO,
	DANGEROUSLY_DROP_TABLES: false,
}

func New(connection *sql.DB, options *Options) (*db, error) {
	if options == nil {
		options = DefaultOptions
	}

	conn := db{
		Connection:  connection,
		logger:      options.Logger,
		log_level:   options.Log_level,
		drop_tables: options.DANGEROUSLY_DROP_TABLES,
	}

	err := conn.bootstrap()
	if err != nil {
		return nil, err
	}

	return &conn, nil
}

func (conn *db) log(level LogLevel, args ...any) {
	// Only log if the level is the same or lower than the configured
	if level > conn.log_level {
		return
	}

	fmt.Fprintf(conn.logger, "[ %s - %-5s ]: ", time.Now().Format(time.DateTime), level.String())
	fmt.Fprintln(conn.logger, args...)
}

func (conn *db) bootstrap() error {
	conn.log(INFO, "Initializing database...")

	sql := ""

	if conn.drop_tables {
		sql += `
			DROP TABLE IF EXISTS nodes;
			DROP TABLE IF EXISTS relationships;
			DROP INDEX IF EXISTS node_class;
			DROP INDEX IF EXISTS relationships_class;
		`
	}

	sql += `
    CREATE TABLE IF NOT EXISTS nodes (
      id INTEGER PRIMARY KEY AUTOINCREMENT,
      _class text NOT NULL,
			name TEXT,
      metadata jsonb DEFAULT '{}'
    );

    CREATE INDEX IF NOT EXISTS node_class on nodes (_class);


    CREATE TABLE IF NOT EXISTS relationships (
      node_from INTEGER NOT NULL,
      node_to INTEGER NOT NULL,
      _class text NOT NULL,
      PRIMARY KEY (node_from, node_to),
      CHECK (node_from != node_to),
      CONSTRAINT fk_node_from_relationships FOREIGN KEY (node_from) REFERENCES nodes(id),
      CONSTRAINT fk_node_to_relationships FOREIGN KEY (node_to) REFERENCES nodes(id)
    );

    CREATE INDEX IF NOT EXISTS relationships_class on relationships (_class);
  `

	conn.log(DEBUG, sql)
	_, err := conn.Connection.Exec(sql)
	if err != nil {
		return err
	}

	return nil
}

func (conn *db) generateNodeFromStruct(shape any) *Node {
	// Get the type and handle pointer types
	t := reflect.TypeOf(shape)
	if t.Kind() == reflect.Ptr {
		t = t.Elem()
	}

	node := Node{
		_id:      -1,
		_class:   strings.ToUpper(t.Name()),
		metadata: shape,
	}
	return &node
}

func (conn *db) RegisterNodeClass(shape any) {
	if conn.node_types == nil {
		conn.node_types = make(NodeType)
	}

	node := conn.generateNodeFromStruct(shape)

	conn.node_types[node._class] = *node

	conn.log(DEBUG, "Registered node class: ", node)
}

func (conn *db) NewCollection(shape any) (*Node, error) {
	collection, err := conn.NewNode("collection", shape)
	if err != nil {
		return nil, err
	}

	return collection, nil
}

func (conn *db) NewNode(name string, metadata any) (*Node, error) {
	if metadata == nil {
		return nil, fmt.Errorf("metadata cannot be nil")
	}

	json_metadata, err := json.Marshal(metadata)
	if err != nil {
		return nil, fmt.Errorf("invalid metadata format: %w", err)
	}

	node := conn.generateNodeFromStruct(metadata)
	node.name = name

	tx, err := conn.Connection.Begin()
	if err != nil {
		return nil, err
	}

	defer tx.Rollback()

	conn.log(DEBUG, "Creating node:", node)

	sql := "INSERT INTO nodes (_class, name, metadata) VALUES ($1, $2, $3) RETURNING id;"

	err = tx.QueryRow(sql, node._class, node.name, json_metadata).Scan(&node._id)
	if err != nil {
		return nil, err
	}

	if err := tx.Commit(); err != nil {
		return nil, err
	}
	return node, nil
}

func (conn *db) GetNode(id int64) (*Node, error) {
	node := Node{_id: id}
	sql := "SELECT _class, metadata FROM nodes WHERE id = $1;"
	conn.log(DEBUG, sql)

	var metadata []byte
	err := conn.Connection.QueryRow(sql, id).Scan(&node._class, &metadata)
	if err != nil {
		conn.log(DEBUG, err)
		return nil, fmt.Errorf("No row matching id = %v", id)
	}

	if err := json.Unmarshal(metadata, &node.metadata); err != nil {
		conn.log(ERROR, err)
		return nil, fmt.Errorf("invalid metadata format: %w", err)
	}
	return &node, nil
}