Initial commit

Half-baked state. Most of the UI is mostly done, but the integration
with Grist (or any other data provider) is still missing.

global.gd

@@ -0,0 +1,57 @@
+extends Node
+
+var data_provider = preload("res://providers/debug_data.gd").new()
+var scale_provider = preload("res://providers/debug_scale.gd").new()
+
+var article_infos: Dictionary[String, ArticleInfo] = {}
+
+var cart: Array[CartEntry] = []
+var current_entry: CartEntry = null
+var cart_total_cents = 0
+
+var scale_grams: int = 120
+var tara_grams: int = 20
+
+signal weights_updated
+signal cart_updated
+
+func _ready() -> void:
+	article_infos = data_provider.load_articles()
+	
+	cart_updated.connect(_on_cart_updated)
+	
+	current_entry = CartEntry.new(article_infos['default_0'])
+	update_weights()
+
+func _on_product_selected(id):
+	current_entry = CartEntry.new(article_infos[id])
+	update_weights()
+
+func _on_cart_updated():
+	# Make sure all cart entries have the correct list index
+	for i in range(len(cart)):
+		cart[i].cart_index = i
+	
+	# Update the total
+	cart_total_cents = 0
+	for entry in Global.cart:
+		cart_total_cents += entry.price_cents
+	
+func update_weights():
+	current_entry.weight_grams = scale_grams - tara_grams
+	current_entry.price_cents = current_entry.weight_grams * current_entry.article_info.price_cents_per_gram
+	weights_updated.emit()
+	
+func set_scale(grams):
+	scale_grams = int(grams)
+	update_weights()
+
+func set_tara(grams):
+	tara_grams = int(grams)
+	update_weights()
+
+func confirm_entry():
+	cart.append(current_entry)
+	current_entry = CartEntry.new(current_entry.article_info)
+	update_weights()
+	cart_updated.emit()