Lost Green

Lost Green is an indoor bike trainer desktop application for:

• connecting fitness devices (smart trainers, power meters, cadence sensors, and heart-rate monitors)
• running structured workouts (including ERG control targets)
• collecting ride data in real time for post-workout analysis

Architecture

This project is built with Elixir Phoenix + Tauri.

• src-elixir: the Phoenix app (UI + backend logic + persistence)
• src-tauri: the desktop host and machine bridge (Bluetooth/WiFi access, sidecar lifecycle)

Why this split:

• The Phoenix app provides the full product UI and application logic.
• Tauri provides a native desktop shell and device access where browser APIs are limited.
• In production, Tauri runs the Phoenix release as a sidecar binary (lost_green_backend-*).

Run locally

Prerequisites

• Elixir/Erlang toolchain (compatible with mix in this repo)
• Rust toolchain (cargo)
• Tauri CLI (cargo install tauri-cli)
• macOS developer tooling (Xcode Command Line Tools)

Toolchain management (mise)

mise is recommended for managing Erlang/Elixir/Rust versions locally.

This repository includes a project toolchain file at mise.toml.

From the repository root:

mise trust
mise install

Then install the Tauri CLI:

cargo install tauri-cli

1) Install and set up dependencies

From src-elixir:

mix setup

2) Start Phoenix (terminal A)

From src-elixir:

mix phx.server

3) Start Tauri (terminal B)

From src-tauri:

SIMULATE_DEVICES=1 cargo tauri dev

Notes:

• SIMULATE_DEVICES accepts 1, true, yes, or on.
• In debug, Tauri first checks for an external backend at http://localhost:4000.
• If Phoenix is already running, Tauri uses it directly; otherwise it attempts sidecar startup.

Release build (macOS)

Run from the repository root:

./scripts/release.sh

Optional flags:

./scripts/release.sh --target x86_64-apple-darwin
./scripts/release.sh --skip-tauri-build

What scripts/release.sh does:

1. Builds Phoenix production assets and code.
2. Builds the Burrito desktop backend release (lost_green_desktop).
3. Copies Burrito output to the Tauri sidecar path (src-tauri/lost_green_backend-<target>).
4. Regenerates/prunes Tauri icons and runs cargo tauri build (unless skipped).

Bundle output is written under:

• src-tauri/target/<target>/release/bundle

Release targets

Current release support is macOS only.

• Default target in release script: aarch64-apple-darwin
• Optional Intel macOS target: x86_64-apple-darwin
• Burrito release config currently only defines macOS (aarch64) packaging.

Linux and Windows may work once additional Burrito targets are configured in src-elixir/mix.exs (releases/0) and the sidecar/bundling wiring is updated accordingly.

Contributor checks

Before opening a PR from src-elixir, run:

mix precommit

Troubleshooting

• cargo tauri dev cannot find backend sidecar:
  • Start Phoenix first in src-elixir with mix phx.server.
  • Or create/update the sidecar with ./scripts/release.sh --skip-tauri-build.
• Tauri opens but app is blank/unreachable:
  • Verify Phoenix is serving on http://localhost:4000.
  • Ensure nothing else is using port 4000.
• No devices found during development:
  • Run with simulated devices enabled: SIMULATE_DEVICES=1 cargo tauri dev.
  • Accepted values are 1, true, yes, or on.