#Polls

• Frontend: Rabbita (Elm-architecture UI framework, compiles to JS)
• Backend: Mocket (HTTP server, compiles to native) + SQLite3 (persistence)
• Shared: Common types, routes, validation, and vote computation compiled for both targets

#Quick Start

moon update
make serve

#Features

• Create polls with a question and 2-6 multiple choice options
• Vote on poll options (client-side duplicate vote prevention)
• View vote results with counts and percentages
• Delete polls
• Data persists in SQLite (polls.db)
• Single codebase, two compilation targets (js for frontend, native for backend)

#Isomorphic Design

#What is shared

• Poll, PollOption, and PollResults types (types.mbt) — structs with derive(ToJson, FromJson). The backend constructs Poll values from SQLite rows (joining polls and poll_options tables). The frontend deserializes the same JSON into the same types.

• Route paths (routes.mbt) — API paths defined once. The frontend calls @shared.api_poll_vote(id) to build request URLs. The backend uses @shared.api_polls for route registration.

• Validation (validation.mbt) — validate_question() and validate_option() enforce length limits. min_options and max_options constants define the allowed range. Same rules, one definition, enforced on both sides.

• Vote computation (logic.mbt) — compute_results() calculates total votes and per-option percentages from a Poll. The same calculation runs on both targets.

#API

#Project Structure

shared/              # Isomorphic code (both js and native)
  types.mbt          #   Poll, PollOption, PollResults with ToJson/FromJson
  routes.mbt         #   API path constants and builders
  validation.mbt     #   Question/option length, option count limits
  logic.mbt          #   Vote counting and percentage computation
backend/main.mbt     # Mocket HTTP server + SQLite3 CRUD (polls + poll_options)
frontend/main.mbt    # Rabbita MVU app (model, update, view)
public/              # Build output for frontend JS
moon.mod.json        # Module config and dependencies
Makefile             # Build and run commands

#Architecture

#System Architecture

graph TB
    subgraph Frontend ["Frontend (target: js)"]
        FM[main.mbt]
        subgraph App ["app/"]
            AT[types.mbt]
            AU[update.mbt]
            AV[view.mbt]
            AS[styles.mbt]
            AUT[update_test.mbt]
            AVT[view_test.mbt]
        end
        FM --> App
    end

    subgraph Backend ["Backend (target: native)"]
        BM[main.mbt]
        BR[routes.mbt]
        BD[db.mbt]
    end

    subgraph Shared ["Shared (target: js + native)"]
        ST[types.mbt]
        SR[routes.mbt]
        SV[validation.mbt]
        SL[logic.mbt]
    end

    Frontend -->|imports| Shared
    Backend -->|imports| Shared

    Backend -->|serves| JS[public/frontend.js]
    FM -->|compiles to| JS

    BD -->|reads/writes| DB[(polls.db\nSQLite)]
    DB -->|polls table| T1[polls\nid, question]
    DB -->|poll_options table| T2[poll_options\nid, poll_id, text, votes]

    Frontend <-->|JSON REST API| Backend

    style Frontend fill:#e1f5fe
    style Backend fill:#fff3e0
    style Shared fill:#e8f5e9
    style DB fill:#fce4ec

#MVU Data Flow

graph LR
    Model -->|render| View
    View -->|user interaction| Msg
    Msg -->|dispatch| Update
    Update -->|new state| Model
    Update -->|side effects| Cmd

    subgraph Messages
        Msg
    end

    subgraph "Msg Variants"
        direction TB
        M1[FetchPolls]
        M2[GotPolls]
        M3[UpdateQuestion / UpdateOption]
        M4[AddOption / RemoveOption]
        M5[CreatePoll / PollCreated]
        M6[Vote / Voted]
        M7[DeletePoll / PollDeleted]
    end

    Msg --- M1
    Msg --- M2
    Msg --- M3
    Msg --- M4
    Msg --- M5
    Msg --- M6
    Msg --- M7

    subgraph Commands
        Cmd -->|GET /api/polls| Fetch[Fetch Polls]
        Cmd -->|POST /api/polls| Create[Create Poll]
        Cmd -->|POST /api/polls/:id/vote| VoteReq[Vote]
        Cmd -->|DELETE /api/polls/:id| Delete[Delete Poll]
    end

    style Model fill:#e1f5fe
    style View fill:#e8f5e9
    style Msg fill:#fff3e0
    style Update fill:#f3e5f5
    style Cmd fill:#fce4ec

#Data Model

erDiagram
    Poll {
        Int id PK
        String question
    }

    PollOption {
        Int id PK
        String text
        Int votes
    }

    PollResults {
        Poll poll
        Int total_votes
        Array percentages "Array of (String, Int)"
    }

    Poll ||--o{ PollOption : "has many"
    Poll ||--|| PollResults : "computed by compute_results()"
    PollResults ||--o{ PollOption : "derives percentages from"