Add support for conditional recipes

src/coffee/models/mod_version.coffee

@@ -144,6 +144,8 @@ module.exports = class ModVersion extends BaseModel
         otherRecipes = []
 
         for recipe in _.values @_recipes
+            continue unless recipe.isConditionSatisfied()
+
             if recipe.itemSlug.matches itemSlug
                 primaryRecipes.push recipe
             else if recipe.produces itemSlug

src/coffee/models/parser_versions/mod_version_parser_v1.coffee

@@ -70,6 +70,21 @@ module.exports = class ModVersionParserV1 extends CommandParserVersionBase
         for name in inputNames
             @_recipeData.input.push @_parseStack name
 
+    _command_onlyIf: (condition)->
+        words = condition.split ' '
+        if words.length < 2 then throw new Error 'condition must include a verb followed by a noun'
+
+        inverted = false
+        if words[0] is 'not'
+            inverted = true
+            words.shift()
+
+        verb = words[0]
+        noun = words[1..].join ' '
+
+        if not (verb in ['item', 'mod']) then throw new Error "unknown verb: #{verb}"
+        @_recipeData.condition = verb:verb, noun:noun, inverted:inverted
+
     _command_pattern: (pattern='')->
         if not @_recipeData? then throw new Error 'cannot declare "pattern" before "recipe"'
         if @_recipeData.pattern? then throw new Error 'duplicate declaration of "pattern"'
@@ -155,10 +170,11 @@ module.exports = class ModVersionParserV1 extends CommandParserVersionBase
         if not recipeData.pattern? then throw new Error 'the "pattern" declaration is required'
 
         recipe = new Recipe
-            input:   @_buildStackList modVersion, recipeData.input, recipeData.pattern
+            condition: recipeData.condition
-            output:  @_buildStackList modVersion, recipeData.output
+            input:     @_buildStackList modVersion, recipeData.input, recipeData.pattern
-            pattern: recipeData.pattern
+            output:    @_buildStackList modVersion, recipeData.output
-            tools:   @_buildStackList modVersion, recipeData.tools
+            pattern:   recipeData.pattern
+            tools:     @_buildStackList modVersion, recipeData.tools
 
         modVersion.addRecipe recipe
         return recipe
@@ -274,6 +290,10 @@ module.exports = class ModVersionParserV1 extends CommandParserVersionBase
         builder
             .line 'recipe:'
             .indent()
+                .onlyIf recipe.condition?, =>
+                    builder.push 'onlyIf: '
+                        .onlyIf recipe.condition.inverted, -> builder.push 'not '
+                        .line recipe.condition.verb, ' ', recipe.condition.noun
                 .onlyIf extraOutputs.length > 0, =>
                     builder
                         .push 'extras: '

src/coffee/models/recipe.coffee

@@ -28,6 +28,7 @@ module.exports = class Recipe extends BaseModel
 
         attributes.pattern = @_parsePattern attributes.pattern
 
+        attributes.condition  ?= null
         attributes.modVersion ?= null
         attributes.tools      ?= []
         options.logEvents     ?= false
@@ -114,6 +115,22 @@ module.exports = class Recipe extends BaseModel
 
         return total
 
+    isConditionSatisfied: (modPack)->
+        return true unless @condition
+        modPack ?= @modVersion?.mod?.modPack
+
+        result = false
+        if @condition.verb is 'item'
+            if modPack?.findItemByName(@condition.noun)?
+                result = true
+        else if @condition.verb is 'mod'
+            modPack.eachMod (mod)->
+                if mod.name is @condition.noun
+                    result = true
+
+        if @condition.inverted then result = not result
+        return result
+
     isPassThroughFor: (itemSlug)->
         amountCreated = 0
         for stack in @output

test/mod_version.test.coffee

@@ -87,6 +87,7 @@ describe 'mod_version.coffee', ->
                 item: Cake
                     recipe:; input: Milk, Sugar, Egg, Wheat; pattern: 000 121 333; extras: 3 Bucket
                     recipe:; input: Milk, Cocoa Beans, Egg, Wheat; pattern: 000 121 333; extras: 3 Bucket
+                    recipe:; input: Cake Slice; pattern: 000 000 000; onlyIf: item Cake Slice
                 item: Bucket
                     recipe:; input: Iron Ingot; pattern: ... 0.0 .0.
             """
@@ -94,3 +95,7 @@ describe 'mod_version.coffee', ->
         it 'finds all recipes which list item as output', ->
             recipes = modVersion.findRecipes ItemSlug.slugify('test__bucket')
             (r.output[0].itemSlug.item for r in recipes).sort().should.eql ['bucket', 'cake', 'cake']
+
+        it 'skip recipes whose conditions are not met', ->
+            recipes = modVersion.findRecipes ItemSlug.slugify 'test__cake'
+            recipes.length.should.equal 2

test/parser_versions/mod_version_parser_v1.test.coffee

@@ -158,6 +158,40 @@ describe 'mod_version_parser_v1.coffee', ->
                 func = -> parser.parse 'item:Bravo; quantity:12; recipe:;'
                 expect(func).to.throw Error, 'cannot declare "quantity" before "recipe"'
 
+        describe 'onlyIf', ->
+
+            beforeEach ->
+                baseText = 'item: Charlie; recipe:; input:Alpha; pattern:...0.0...; '
+
+            it 'understands the "item" verb', ->
+                modVersion = parser.parse baseText + 'onlyIf: item Iron Ingot'
+                recipes = []
+                modVersion.eachRecipe (recipe)-> recipes.push recipe
+                recipe = recipes[0]
+                recipe.condition.should.eql verb:'item', noun:'Iron Ingot', inverted:false
+
+            it 'understands the "mod" verb', ->
+                modVersion = parser.parse baseText + 'onlyIf: mod BuildCraft'
+                recipes = []
+                modVersion.eachRecipe (recipe)-> recipes.push recipe
+                recipe = recipes[0]
+                recipe.condition.should.eql verb:'mod', noun:'BuildCraft', inverted:false
+
+            it 'understands inverting verbs', ->
+                modVersion = parser.parse baseText + 'onlyIf: not item Iron Ingot'
+                recipes = []
+                modVersion.eachRecipe (recipe)-> recipes.push recipe
+                recipe = recipes[0]
+                recipe.condition.should.eql verb:'item', noun:'Iron Ingot', inverted:true
+
+            it 'requires at least two words', ->
+                func = -> parser.parse baseText + 'onlyIf: item'
+                expect(func).to.throw Error, 'verb followed by a noun'
+
+            it 'only allows known verbs', ->
+                func = -> parser.parse baseText + 'onlyIf: foo Iron Ingot'
+                expect(func).to.throw Error, 'unknown verb'
+
         describe 'output', ->
 
             beforeEach ->
@@ -250,6 +284,11 @@ describe 'mod_version_parser_v1.coffee', ->
                         input: furnace fuel, Iron Dust
                         pattern: .1. ... .0.
                         tools: Furnace
+                    recipe:
+                        onlyIf: item Redstone Furnace
+                        input: Iron Ore
+                        pattern: ... .0. ...
+                        tools: Redstone Furnace
             """
 
         it 'can round-trip a data file', ->