custom_tech_tree.lua

--[[ INSTRUCTIONS:
I. Common stuff:
1) Copy custom_tech_tree.lua to your mod directory.
2) Add a line to your modmain:
    modimport "custom_tech_tree.lua"
3) After that add one of these lines to modmain:
    AddNewTechTree("YOUR_TREE_NAME")
    AddNewTechTree("ANOTHER_TREE_NAME",3) --makes 3 levels, e.g. ANOTHER_TREE_NAME_ONE, also _TWO and _THREE
    etc. The number means number of levels.

II. Structure prefab:
1) Add "prototyper" tag to crafting structure in pristine state (before SetPristine).
    inst:AddTag("prototyper")
2) Also you may add "giftmachine" tag if you want.
3) Add prototyper:
    inst:AddComponent("prototyper")
    inst.components.prototyper.trees = TUNING.PROTOTYPER_TREES.YOUR_TREE_NAME_ONE

III. Add a recipe:
    AddRecipe("your_item_prefab", { Ingredient("cutgrass", 1), },
    RECIPETABS.TOOLS, TECH.YOUR_TREE_NAME_ONE,
    nil, nil, nil, nil, nil,
    "images/your_altas_name.xml")

IV. Add text constants (you can support a few languages if you like):
    STRINGS.UI.CRAFTING.YOUR_TREE_NAME_ONE = "You need a <custom structure name> to make it."

--]]
_G=GLOBAL

if _G.rawget(_G,"AddNewTechTree") then --Make compatible with other mods.
    AddNewTechTree = _G.AddNewTechTree --adding to the env of the mod.
    return
end

--Prepare variables. Save existing environment.

local db = {} -- db.MAGIC == 0
local db_new_techs = {} -- Only new trees, e.g. db_new_techs.NEWTREE == 0
local db_new_classified = {} --e.g.  db_new_classified.NEWTREE == "custom_NEWTREE_level"
local db_new_builder_name = {} -- e.g. db_new_builder_name.NEWTREE == "builder.accessible_tech_trees.NEWTREE"

for k,v in pairs(_G.TECH.NONE) do --initialize (copy)
    db[k] = 0
end
if TUNING.PROTOTYPER_TREES then --just for sure
    for k,v in pairs(TUNING.PROTOTYPER_TREES.SCIENCEMACHINE) do
        db[k] = 0
    end
end

local function UpdateDB(newtree_name) --add new element to our table, create common stuff
    db[newtree_name] = 0
    db_new_techs[newtree_name] = 0
    db_new_classified[newtree_name] = "custom_" .. newtree_name .. "_level"
    db_new_builder_name[newtree_name] = "builder.accessible_tech_trees." .. newtree_name
end

--Custom little hack instrument.
local getupvalue, setupvalue, getinfo = _G.debug.getupvalue, _G.debug.setupvalue, _G.debug.getinfo
local function inject_local(fn, local_fn_name)
    print("INJECT... Trying to find",local_fn_name)
    local info = getinfo(fn, "u")
    local nups = info and info.nups
    for i = 1, nups do
        local name, val = getupvalue(fn, i)
        if (name == local_fn_name) then
            return val, i
        end
    end
    print("CRITICAL ERROR: Can't find variable "..tostring(upvalue_name).."!")
end



--Thanks rezecib for the all places in the code:
--http://forums.kleientertainment.com/topic/69813-how-to-make-custom-tech-tree/
--1) constants, TECH.NONE.NEWTREE = 0, also TECH.NEWTREE_ONE, etc (these are optional, but get used in the recipes a lot)

local function AddNewTechConstants(newtree_name)
    _G.TECH.NONE[newtree_name] = 0
    _G.TECH.LOST[newtree_name] = 10
    if TUNING.PROTOTYPER_TREES then
        for k,tbl in pairs(TUNING.PROTOTYPER_TREES) do
            tbl[newtree_name] = 0
        end
    end
end

local TECH_LEVELS = {'_ONE','_TWO','_THREE','_FOUR','_FIVE'} -- e.g. NEWTREE_ONE
local saved_tech_names = {} --for text hint in GetHintTextForRecipe
local function AddTechLevel(newtree_name, level)
    level = level or 1
    local level_name
    if TECH_LEVELS[level] then
        level_name = newtree_name .. TECH_LEVELS[level]
    else
        level_name = newtree_name .. "_" .. tostring(level)
    end
    --Save new name
    if not saved_tech_names[newtree_name] then
        saved_tech_names[newtree_name] = {}
    end
    saved_tech_names[newtree_name][level] = level_name
    _G.TECH[level_name] = {[newtree_name] = level} --for using in recipes
    --for using in new crafting structures:
    if TUNING.PROTOTYPER_TREES then
        local new_tree = {} --make new instance
        for k,v in pairs(db) do --copy old data to new instance
            new_tree[k] = v
        end
        new_tree[newtree_name] = level --> make structure useful
        TUNING.PROTOTYPER_TREES[level_name] = new_tree
    end
end



--2) components/builder:EvaluateTechTrees makes specific mention to each of the trees in order to bring in self.bonus. Looks like it might involve a messy override in order to add intrinsic character bonuses to a tree, because it does both the check and the result without any functions in between to hook into... You could maybe do it by replacing self.accessible_tech_trees with a proxy table that has a metatable so you can intercept the assignment? That's pretty gross, though.

--NB: No bonuses for custom tech trees! //star

--But we still to check if player goes away (over time).
local prototyper = _G.require "components/prototyper"
local old_TurnOn = prototyper.TurnOn
function prototyper:TurnOn(doer, ...)
    if doer.task_custom_tech then
        doer.task_custom_tech:Cancel()
    end
    doer.task_custom_tech = doer:DoTaskInTime(1.5,function(player)
        local trees_changed = false
        local tech_tree = player.components.builder.accessible_tech_trees
        for tech_name, _ in pairs(db_new_techs) do
            if tech_tree[tech_name] > 0 then
                trees_changed = true
                tech_tree[tech_name] = 0
            end
        end
        if trees_changed then
            player:PushEvent("techtreechange", {level = tech_tree})
            player.replica.builder:SetTechTrees(tech_tree)
        end
        player.task_custom_tech = nil
    end)
    return old_TurnOn(self,doer, ...)
end



--3) components/builder_replica has Setters and Getters for each tree's intrinsic bonuses, these are called later in recipepopup

local replica = _G.require "components/builder_replica"
local old_SetTechTrees = replica.SetTechTrees
function replica:SetTechTrees(techlevels,...)
    if self.classified ~= nil then
        for tech_name,v in pairs(db_new_techs) do
            self.classified[db_new_classified[tech_name] ]:set(techlevels[tech_name] or 0)
        end
    end
    return old_SetTechTrees(self,techlevels,...)
end



--4) KnowsRecipe explicitly checks each tree in both builder and builder_replica

--No custom bonus.
--So we should just restrict custom tech trees as bonus.

local AllRecipes = _G.AllRecipes

local builder = _G.require "components/builder"
local old_KnowsRecipe = builder.KnowsRecipe
function builder:KnowsRecipe(recname)
    local result = old_KnowsRecipe(self, recname)
    if result then
        if self.freebuildmode or table.contains(self.recipes, recname) then
            return true
        end
        local recipe = AllRecipes[recname]
        for tech_name,v in pairs(db_new_techs) do
            if recipe.level[tech_name] > 0 then
                return false --no custom bonus
            end
        end
    end
    return result
end

local old_KnowsRecipe_replica = replica.KnowsRecipe
function replica:KnowsRecipe(recname)
    if self.inst.components.builder ~= nil then
        return self.inst.components.builder:KnowsRecipe(recname)
    end
    local result = old_KnowsRecipe_replica(self, recname)
    if result then
        if self.classified.isfreebuildmode:value() or
            self.classified.recipes[recname] ~= nil and self.classified.recipes[recname]:value()
        then
            return true
        end
        local recipe = AllRecipes[recname]
        for tech_name,v in pairs(db_new_techs) do
            if recipe.level[tech_name] > 0 then
                return false --no custom bonus
            end
        end
    end
    return result
end



--5) components/prototyper constructor, self.trees.NEWTREE = 0, and have any prototyper prefabs you make increase that

AddClassPostConstruct("components/prototyper", function(this) --increase table used by :GetTechTrees function.
    this.trees = {}
    for k,v in pairs(db) do --db is already prepared for copying.
        this.trees[k] = v
    end
end)



--6) prefabs/player_classified OnTechTreesDirty checks each of them explicitly. You could add a listener for "techtreesdirty" and make your check there. Also inst.newtreelevel would need to be added.

--Need to inject in local function OnTechTreesDirty and replace it.
--Pricey hack, so should be done only once per game session.
local function PlayerClassifiedHack()
    local RegisterNetListeners_fn = inject_local(_G.Prefabs.player_classified.fn, "RegisterNetListeners")
    local OnTechTreesDirty_fn_old, var_num = inject_local(RegisterNetListeners_fn, "OnTechTreesDirty")
    local OnTechTreesDirty_fn_new = function(inst)
        for tech_name,v in pairs(db_new_techs) do
            if inst[db_new_classified[tech_name] ] == nil then
                print("error: inst."..db_new_classified[tech_name].." == nil")
            else
                inst.techtrees[tech_name] = inst[db_new_classified[tech_name] ]:value()
            end
        end
        return OnTechTreesDirty_fn_old(inst)
    end
    setupvalue(RegisterNetListeners_fn, var_num, OnTechTreesDirty_fn_new)
end
local player_classified_hacked = false
AddPrefabPostInit("world",function(w)
    if not player_classified_hacked then
        player_classified_hacked = true
        PlayerClassifiedHack()
    end
end)

--Create network variables.
local net_tinybyte = _G.net_tinybyte
AddPrefabPostInit("player_classified",function(inst) --print("ADDPREFABPOSTINIT player_classified")
    for tech_name,v in pairs(db_new_techs) do
        inst[db_new_classified[tech_name] ] = net_tinybyte(inst.GUID, db_new_builder_name[tech_name], "techtreesdirty")
    end
end)



--7) recipe, self.level.NEWTREE = self.level.NEWTREE or 0 needs to be added, could be done by overriding Recipe._ctor, or doing an AddClassPostConstruct (maybe? the recipe.lua file doesn't return the class though, so maybe not)

AddPrefabPostInit("world",function(w) --Fixing all recipes. Just for sure.
    for rec_name, recipe in pairs(_G.AllRecipes) do
        for tree_name,_ in pairs(db_new_techs) do
            recipe.level[tree_name] = recipe.level[tree_name] or 0
        end
    end
end)



--8) tuning, PROTOTYPER_TREES needs to have each of its entries modified (although I think if you don't they should default to zero from the other changes)

-- (+) Done in AddTechLevel().

--9) widgets/recipepopup GetHintTextForRecipe takes into account player intrinsic bonuses to trees for the help text. This looks like it might need to be overridden

local save_hint_recipe

--We need just a link to recipe.
do
    local recipepopup = _G.require "widgets/recipepopup"
    local RecipePopup_Refresh_fn = recipepopup.Refresh
    local old_GetHintTextForRecipe, num_var = inject_local(RecipePopup_Refresh_fn,"GetHintTextForRecipe")
    if old_GetHintTextForRecipe then
        setupvalue(RecipePopup_Refresh_fn, num_var, function(player, recipe)
            save_hint_recipe = recipe
            return old_GetHintTextForRecipe(player, recipe)
        end)
    end
end

--Here we can use the link.
local CRAFTING = _G.STRINGS.UI.CRAFTING --See STRINGS.UI.CRAFTING.NEEDSCIENCEMACHINE
AddClassPostConstruct("widgets/recipepopup",function(self)
    local old_SetString = self.teaser.SetString
    function self.teaser:SetString(str)
        --print("Show text",str,tostring(save_hint_recipe))
        if str == "Text not found." and save_hint_recipe ~= nil  then --Probably custom recipe
            local custom_tech, custom_level
            for tech_name, _ in pairs(db_new_techs) do --Check if it's really custom.
                custom_level = save_hint_recipe.level[tech_name]
                if custom_level > 0 then
                    custom_tech = tech_name
                    break
                end
            end
            if custom_tech then
                str = CRAFTING[saved_tech_names[custom_tech][custom_level] ] or str
            end
        end
        return old_SetString(self,str)
    end
end)



--Main function of the lib.
function AddNewTechTree(newtree_name, num_levels)
    UpdateDB(newtree_name) --update local tables
    AddNewTechConstants(newtree_name) --_G.TECH.NEWTREE
    num_levels = num_levels or 1
    for i = 1, num_levels do --_G.TECH.NEWTREE_ONE and TUNING.PROTOTYPER_TREES.NEWTREE_ONE, two, three etc.
        AddTechLevel(newtree_name, i)
    end
end

--Global define
_G.AddNewTechTree = AddNewTechTree