# gol-simulation Specification

## Purpose
Defines Conway's Game of Life simulation behavior, including ticking, pause/resume, stepping, speed control, and paused-only cell editing.

## Requirements

### Requirement: Simulation applies Conway's rules
The system SHALL advance the grid by one generation per tick using Conway's rules with wall boundaries.

#### Scenario: Tick advances grid
- **WHEN** a tick occurs
- **THEN** each cell's next state follows Conway's rules based on its eight neighbors

### Requirement: Simulation starts paused
The system SHALL start with the simulation paused.

#### Scenario: Initial state
- **WHEN** the application starts
- **THEN** the simulation is paused

### Requirement: Pause can be toggled
The system SHALL toggle between paused and running when the pause action is triggered.

#### Scenario: Toggle pause
- **WHEN** the user triggers the pause action
- **THEN** the simulation switches between paused and running

### Requirement: Single step advances one generation
The system SHALL advance exactly one generation when the step action is triggered while paused.

#### Scenario: Step while paused
- **WHEN** the simulation is paused and the user triggers step
- **THEN** the grid advances by one generation
- **AND** the simulation remains paused

### Requirement: Step is ignored while running
The system SHALL ignore the step action while the simulation is running.

#### Scenario: Step while running
- **WHEN** the simulation is running and the user triggers step
- **THEN** no extra generation is applied

### Requirement: Speed is adjustable
The system SHALL change the tick interval when speed_up or speed_down is triggered, within supported bounds.

#### Scenario: Speed up
- **WHEN** the user triggers speed_up
- **THEN** the tick interval decreases (simulation runs faster)

#### Scenario: Speed down
- **WHEN** the user triggers speed_down
- **THEN** the tick interval increases (simulation runs slower)

### Requirement: Cell editing only while paused
The system SHALL allow editing cells only while the simulation is paused.

#### Scenario: Edit while paused
- **WHEN** the simulation is paused and the user clicks a cell
- **THEN** the cell state changes according to the mouse button

#### Scenario: No edit while running
- **WHEN** the simulation is running and the user clicks a cell
- **THEN** the grid is not modified by the click

### Requirement: Left click sets cell alive
The system SHALL set the clicked cell to alive when the left mouse button is pressed while paused.

#### Scenario: Set alive
- **WHEN** the simulation is paused and the user left-clicks a cell
- **THEN** that cell becomes alive

### Requirement: Right click sets cell dead
The system SHALL set the clicked cell to dead when the right mouse button is pressed while paused.

#### Scenario: Set dead
- **WHEN** the simulation is paused and the user right-clicks a cell
- **THEN** that cell becomes dead

### Requirement: Drag paints cells
The system SHALL paint cells while dragging with the left button (alive) or right button (dead) while paused.

#### Scenario: Drag paint
- **WHEN** the simulation is paused and the user drags with left button held
- **THEN** cells under the cursor become alive