import Combine
import Foundation
import GRDB
import SwiftUI

// MARK: - Models protocol
typealias DBStorable = Codable & FetchableRecord & Identifiable & PersistableRecord & TableRecord

// MARK: - Database init
final class Database {
    static let shared = Database()
    let _db: DatabaseQueue

    private init() {
        do {
            // Create db folder if not exists
            let fileManager = FileManager.default
            let appSupportURL = try fileManager.url(
                for: .applicationSupportDirectory, in: .userDomainMask,
                appropriateFor: nil, create: true
            )
            let directoryURL = appSupportURL.appendingPathComponent("ConversationsClassic", isDirectory: true)
            try fileManager.createDirectory(at: directoryURL, withIntermediateDirectories: true)

            // Open or create the database
            let databaseURL = directoryURL.appendingPathComponent("db.sqlite")
            _db = try DatabaseQueue(path: databaseURL.path, configuration: Database.config)

            // Some debug info
            #if DEBUG
                print("Database path: \(databaseURL.path)")
            #endif

            // Apply migrations
            try Database.migrator.migrate(_db)
        } catch {
            fatalError("Database initialization failed: \(error)")
        }
    }
}

// MARK: - Config
private extension Database {
    static let config: Configuration = {
        var config = Configuration()
        #if DEBUG
            // verbose and debugging in DEBUG builds only.
            config.publicStatementArguments = true
            config.prepareDatabase { db in
                db.trace { print("SQL> \($0)\n") }
            }
        #endif
        return config
    }()
}