Use `TCA`, `GRDB` and the `swift-dependencies` together

Sharing_GRDB_in_TCAApp.swift

//
//  Sharing_GRDB_in_TCAApp.swift
//  Sharing-GRDB-in-TCA
//
//  Created by Andreas Seeger on 15.06.2025.
//

import ComposableArchitecture
import OSLog
import SharingGRDB
import SwiftUI

@main
struct Sharing_GRDB_in_TCAApp: App {
  @State var store: StoreOf<ItemListFeature>

  init() {
    prepareDependencies {
      $0.defaultDatabase = try! appDatabase()
    }
    self.store = Store(
      initialState: ItemListFeature.State()) {
      ItemListFeature()
    }
  }

  var body: some Scene {
    WindowGroup {
      ItemListView(store: store)
    }
  }
}

// MARK: Item Feature
@Reducer
struct ItemListFeature {
  @Dependency(\.defaultDatabase) var defaultDatabase

  @ObservableState
  struct State {
    @FetchAll var items: [Item]
  }

  enum Action {
    case addItem
  }

  var body: some Reducer<State, Action> {
    Reduce { state, action in
      switch action {
      case .addItem:
        return .run { _ in
          do {
            let newItem = Item(name: "New Item")
            try defaultDatabase.write { db in
              try Item.insert { newItem }
                .execute(db)
            }
          } catch {
            logger.error("Failed to add item: \(error)")
          }
        }
      }
    }
  }
}

//MARK: Item View
struct ItemListView: View {
  @Bindable var store: StoreOf<ItemListFeature>

  var body: some View {
    NavigationView {
      List {
        if store.items.isEmpty {
          ContentUnavailableView {
            Text("No items available. Tap the plus button to add a new item.")
          }
        }
        ForEach(store.items) { item in
          Text(item.name)
        }
      }
      .toolbar {
        ToolbarItem(placement: .navigationBarTrailing) {
          Button("Add Item", systemImage: "plus") {
            store.send(.addItem)
          }
        }
      }
    }
  }
}

#Preview {
  let store = Store(
    initialState: ItemListFeature.State()) {
    ItemListFeature()
  }

  ItemListView(store: store)
}

//MARK: Item Model
@Table
struct Item: Identifiable  {
  let id: UUID
  let name: String

  init(
    id: UUID = UUID(),
    name: String
  ) {
    self.id = id
    self.name = name
  }
}

//MARK: App Database
func appDatabase() throws -> any DatabaseWriter {
  @Dependency(\.context) var context
  var configuration = Configuration()
  configuration.foreignKeysEnabled = true
  #if DEBUG
  configuration.prepareDatabase { db in
    db.trace(options: [.profile, .statement]) { event in
      switch event {
      case .statement(let sql):
        logger.debug("SQL: \(sql)")
      case .profile(let sql, let duration):
        logger.debug("SQL: \(sql) (\(duration)s)")
      }
    }
  }
  #endif
  let path = URL.documentsDirectory.appendingPathComponent("db.sqlite").path()
  logger.info("open \(path)")
  #if DEBUG
  // Delete the database file if it exists if needed
//    try? FileManager.default.removeItem(atPath: path)
  #endif
  let database = try DatabasePool(path: path, configuration: configuration)
  var migrator = DatabaseMigrator()
  #if DEBUG
  migrator.eraseDatabaseOnSchemaChange = true
  #endif
  migrator.registerMigration("Create items table") { db in
    try db.create(table: "items") { t in
      t.primaryKey("id", .text)
      t.column("name", .text).notNull()
    }
  }
  try migrator.migrate(database)
  return database
}

private let logger = Logger(subsystem: "ch.appfros.Sharing-Grdb-in-TCA", category: "Database")

Requires the packages swift-composable-architecture and sharing-grdb (though I am not quite sure to what extend I am even using sharing-grdb at this stage–the custom ItemRepository is heavily leveraging GRDB and Dependency and not using @FetchAll at the moment …)

Cool separation of concern anyways in my opinion (also, was only able to spin this up with the help of Cursor 🥴)

Turns out that using sharing-grdb and swift-dependencies is discouraged by Pointfree – so I got rid of that abstraction.