foundryvtt-mgt2/.github/copilot-instructions.md

Copilot Instructions for foundryvtt-mgt2

Project Overview

This is a Foundry VTT game system implementing Mongoose Publishing Traveller 2nd Edition (MGT2). It runs entirely in the browser within the FoundryVTT platform — there is no Node.js runtime or backend server to develop against.

The distributed entry point is mgt2.bundle.js (pre-bundled from src/). CSS is compiled from src/sass/ to styles/mgt2.min.css. No build tooling (package.json, webpack, etc.) is committed to the repo, so bundling is done externally.

Architecture

Entry Point & Initialization

src/module/core.js is the main module. It runs in the FoundryVTT init hook and:

• Registers all Actor/Item document classes
• Registers all TypeDataModel schemas (datamodels.js)
• Registers sheets (actor and item)
• Preloads Handlebars templates

Document Classes

Class	File	Purpose
TravellerActor	actors/actor.js	Extends Actor; delegates character logic to ActorCharacter
ActorCharacter	actors/character.js	Static methods for character-specific actor logic
TravellerItem	item.js	Extends Item
MGT2Combatant	actors/actor.js	Extends Combatant

Sheets

• TravellerActorSheet (actors/character-sheet.js) — character sheet. Uses templates/actors/actor-sheet.html. getData() returns context.data (not the full context).
• TravellerItemSheet (item-sheet.js) — item sheet. Template is dynamically resolved as templates/items/{item.type}-sheet.html.
• VehiculeSheet (actors/vehicule-sheet.js) — vehicle actor sheet.

Data Models

All schemas are TypeDataModels defined in src/module/datamodels.js. Actor types: character, vehicule. Item types: contact, career, disease, item, equipment, talent, armor, weapon, computer, container, species.

The CharacterData model uses a helper createCharacteristicField() for the 12 characteristics (strength, dexterity, endurance, intellect, education, social, morale, luck, sanity, charm, psionic, other). Each characteristic has .value, .max, and .dm fields.

Config Constants

src/module/config.js exports MGT2 — a set of frozen objects mapping internal keys to i18n strings (e.g., MGT2.Difficulty.Average). Accessible at runtime via CONFIG.MGT2.

Templates

Handlebars templates live in templates/. Paths always use the FoundryVTT-relative prefix systems/mgt2/templates/.... Partial templates (used across sheets) live in templates/items/parts/.

Styles & Theming

SASS source is in src/sass/. The active theme is a CSS class applied to every sheet element — e.g. ["mgt2", game.settings.get("mgt2", "theme"), "sheet", ...]. Available themes: black-and-red, mwamba, blue.

Localization

All user-facing strings go through game.i18n.localize(). Keys follow the pattern MGT2.Section.Key. String definitions are in lang/en.json and lang/fr.json.

Chat Cards

ChatHelper (chatHelper.js) hooks into renderChatMessage to attach button listeners. Chat card templates are in templates/chat/.

Key Conventions

• getData() returns context.data — the character sheet's getData() calls super.getData() then returns context.data, not context itself. Keep this pattern for character sheet overrides.
• Actor logic delegation — TravellerActor is thin; type-specific logic lives in static methods on ActorCharacter. Follow this pattern for new actor types.
• Settings keys — always namespaced as game.settings.get("mgt2", "settingName"). Settings are registered in settings.js.
• vehicule spelling — the actor type and related files use the French spelling vehicule (not vehicle). Do not rename.
• Template paths — always use the full FoundryVTT path systems/mgt2/templates/... in JS; never relative paths.
• i18n keys in config — config.js stores i18n key strings (not translated text). Actual translation happens at render time via game.i18n.localize().
• life is the primary token attribute — configured in system.json as primaryTokenAttribute: "life".