AssemblySim

Event-driven assembly line simulator written in Rust. It models time as discrete events, handles machine/staff availability, and provides a Ratatui terminal UI for monitoring queues, status, and progress.

What’s Included

• Discrete event engine with priority scheduling and automatic time advancement.
• Machine buckets (multiple identical machines per step) and staff assignment with skills.
• Material pipelines driven by per-step queues; items advance when a step completes.
• Terminal UI (Ratatui) with metrics, per-step queues, and tabbed status for machines/staff.
• JSON-configurable scenarios with item count, machines, staff, and process steps.
• Tests for core simulation components.

Quick Start

cargo run -- --config test.json

Controls (in the UI):

• space – play/pause
• n – step once
• tab – switch status tab (Machines/Staff)
• q – quit

The sim auto-pauses when all items are finished (finished goods == items).

Config Format (JSON)

{
  "items": 100,
  "machines": [
    { "id": 0, "name": "Dough Station", "staff_required": 1 },
    { "id": 1, "name": "Oven", "staff_required": 1, "count": 2 },
    { "id": 2, "name": "Decorator Table", "staff_required": 1, "count": 2 },
    { "id": 3, "name": "Cooling Rack", "is_automated": true }
  ],
  "staff": [
    { "id": 0, "name": "User1", "role": { "id": 0, "name": "Floater", "machine_ids": [] } },
    { "id": 1, "name": "User2", "role": { "id": 1, "name": "Floater", "machine_ids": [] } }
  ],
  "processes": [
    { "machine_id": 0, "duration": 12 },
    { "machine_id": 1, "duration": 30 },
    { "machine_id": 2, "duration": 15 },
    { "machine_id": 3, "duration": 10 }
  ]
}

Notes:

• items = number of items to push through all steps.
• Each processes entry is a step in order; machine_id refers to a bucket in machines.
• count lets you define multiple identical machines in a bucket.
• If is_automated is false (default), staff must be available for the full duration.

UI Layout

• Metrics: elapsed time, machines/staff counts, idle time, finished goods, controls.
• Status (tabbed): Machines (busy/idle, waiting reason) or Staff (busy/idle, waiting).
• Process Queues: one card per step showing queue length, busy/total machines, duration.

Project Structure

• src/main.rs – CLI + TUI runner, config loading, pipeline orchestration.
• src/logger.rs – logging helper.
• src/model/ – core simulation types:
  • time.rs – event queue, simulator.
  • staff_scheduling.rs – production simulator with staff/machines.
  • machine.rs, staff.rs, simulation_example.rs, etc.
• Docs & guides: START_HERE.md, SUMMARY.md, TIME_SIMULATION_GUIDE.md, VISUAL_GUIDE.md, WHAT_CHANGED.md, PRACTICAL_EXAMPLES.rs.

Running Tests

cargo test

Key Concepts

• Discrete event simulation: jump to next event time instead of ticking every unit.
• Min-heap ordering: earliest events processed first.
• Machine buckets: multiple identical machines per step.
• Staff assignment: respects required staff count and machine skills; released on completion.
• Material flow: step completion enqueues the next step; queues drive work, not per-item threads.

Common Tweaks

• Speed: adjust tick_rate and time step logic in step_simulation (defaults: 50 ms UI tick, up to +10 mins per sim tick).
• Visualization: edit draw_process_queues or draw_status_tabs in main.rs.
• Config: add machines with count, add staff with restricted machine_ids, change items to scale load.