Database

---
title: MoveListDB Architecture
---
graph TB
    subgraph wikiWavu["wikiWavu feature module"]
        Interface["MoveListDB Interface"]
        UseCase["CacheMoveListUseCase"]
        UseCase -->|depends on| Interface
    end

    subgraph botModule["Discord bot"]
        InMemory["InMemoryMoveListDB"]
        BotDI["Koin DI module<br/>bind InMemoryDB → Interface"]
        InMemory -.->|implements| Interface
        BotDI -->|provides| InMemory
    end

    subgraph composeApp["composeApp"]
        Room["RoomMoveListDB"]
        AppDI["Koin DI module<br/>bind RoomDB → Interface"]
        Room -.->|implements| Interface
        AppDI -->|provides| Room
    end

    style wikiWavu fill:#fff4e1,stroke:#333,stroke-width:2px,color:#000
    style botModule fill:#e1f5ff,stroke:#333,stroke-width:2px,color:#000
    style composeApp fill:#ffe1f0,stroke:#333,stroke-width:2px,stroke-dasharray: 5 5,color:#000

    style Interface fill:#fff,color:#000
    style UseCase fill:#fff,color:#000
    style InMemory fill:#fff,color:#000
    style BotDI fill:#fff,color:#000
    style Room fill:#fff,color:#000
    style AppDI fill:#fff,color:#000

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There are differences between the end clients:

• Discord bot - uses in-memory database (something like Map<String,Move>) ¹
• mobile apps - use SQL database (Room)

Because of that split, each end client provides its own MoveListDB implementation. Koin then binds the implementation to the interface.

I highly encourage you to use this approach when creating a Wiki-based feature module for these reasons:

• we do not want to make an API call for every query
• bots do not need persistent data that survives process death
  • the bot runs continuously and if the bot crashes, we have bigger issues to worry about
  • we download fresh data every hour ² to stay in sync anyway
• mobile clients need persistent data because their whole point is offline data access
  • allows for longer-period data downloads (6 hours by default)
  • also allows manual data refresh

---

¹ A simple in-memory implementation: LINK

² One hour seems to be about right to get fresh community updates, especially when a new character releases