local S = minetest.get_translator 'pipeworks'
-- cache some recipe data to avoid calling the slow function
-- minetest.get_craft_result() every second
local autocrafterCache = {}

local next = next

local function count_index(invlist)
    local index = {}
    for _, stack in pairs(invlist) do
        stack = ItemStack(stack)
        if not stack:is_empty() then
            local stack_name = stack:get_name()
            index[stack_name] = (index[stack_name] or 0) + stack:get_count()
        end
    end
    return index
end

local function get_item_info(stack)
    local name = stack:get_name()
    local def = minetest.registered_items[name]
    local description = def and def.description or S 'Unknown item'
    return description, name
end

-- Get best matching recipe for what user has put in crafting grid.
-- This function does not consider crafting method (mix vs craft)
local function get_matching_craft(output_name, example_recipe)
    local recipes = minetest.get_all_craft_recipes(output_name)
    if not recipes then return example_recipe end

    if 1 == #recipes then return recipes[1].items end

    local index_example = count_index(example_recipe)
    local best_score = 0
    local index_recipe, best_index, score, group
    for i = 1, #recipes do
        score = 0
        index_recipe = count_index(recipes[i].items)
        for recipe_item_name, _ in pairs(index_recipe) do
            if index_example[recipe_item_name] then
                score = score + 1
            elseif recipe_item_name:sub(1, 6) == 'group:' then
                group = recipe_item_name:sub(7)
                for example_item_name, _ in pairs(index_example) do
                    if minetest.get_item_group(example_item_name, group) ~= 0 then
                        score = score + 1
                        break
                    end
                end
            end
        end
        if best_score < score then
            best_index = i
            best_score = score
        end
    end

    return best_index and recipes[best_index].items or example_recipe
end

local function get_craft(pos, inventory, hash)
    local hash = hash or minetest.hash_node_position(pos)
    local craft = autocrafterCache[hash]
    if craft then return craft end

    local example_recipe = inventory:get_list 'recipe'
    local output, decremented_input = minetest.get_craft_result {
        method = 'normal',
        width = 3,
        items = example_recipe,
    }

    local recipe = example_recipe
    if output and not output.item:is_empty() then
        recipe = get_matching_craft(output.item:get_name(), example_recipe)
    end

    craft = {
        recipe = recipe,
        consumption = count_index(recipe),
        output = output,
        decremented_input = decremented_input.items,
    }
    autocrafterCache[hash] = craft
    return craft
end

local global_reserved_slots = {}
local h = core.hash_node_position

local function reserve_slots(pos, meta)
    local inv = meta:get_inventory()
    local recipe_inv = inv:get_list 'recipe'
    local reserved_slots = {}
    for i = 1, 9 do
        reserved_slots[i] = recipe_inv[i]:get_name()
        reserved_slots[recipe_inv[i]:get_name()] = i
    end
    global_reserved_slots[h(pos)] = reserved_slots
end

local function get_reserved_slots_or_reserve_them(pos)
    local reserved_slots = global_reserved_slots[h(pos)]
    if not reserved_slots then
        reserve_slots(pos, core.get_meta(pos))
        reserved_slots = global_reserved_slots[h(pos)]
    end
    return reserved_slots
end

local function reserved_items_formspec(pos)
    local fs = {}
    local offset = { 0.22, 4 }
    local reserved_slots = get_reserved_slots_or_reserve_them(pos)
    for i = 1, 9 do
        local name = reserved_slots[i]
        fs[#fs + 1] = string.format('item_image[%s,%s;1,1;%s]', offset[1], offset[2], name)
        offset[1] = offset[1] + 1.25
    end
    return table.concat(fs)
end
-- From a consumption table with groups and an inventory index,
-- build a consumption table without groups
local function calculate_consumption(inv_index, consumption_with_groups)
    inv_index = table.copy(inv_index)
    consumption_with_groups = table.copy(consumption_with_groups)

    -- table of items to actually consume
    local consumption = {}
    -- table of ingredients defined as one or more groups each
    local grouped_ingredients = {}

    -- First consume all non-group requirements
    -- This is done to avoid consuming a non-group item which
    -- is also in a group
    for key, count in pairs(consumption_with_groups) do
        if key:sub(1, 6) == 'group:' then
            -- build table with group recipe items while looping
            grouped_ingredients[key] = key:sub(7):split ','
        else
            -- if the item to consume doesn't exist in inventory
            -- or not enough of them, abort crafting
            if not inv_index[key] or inv_index[key] < count then return nil end

            consumption[key] = (consumption[key] or 0) + count
            consumption_with_groups[key] = consumption_with_groups[key] - count
            assert(consumption_with_groups[key] == 0)
            consumption_with_groups[key] = nil
            inv_index[key] = inv_index[key] - count
            assert(inv_index[key] >= 0)
        end
    end

    -- helper function to resolve matching ingredients with multiple group
    -- requirements
    local function ingredient_groups_match_item(ingredient_groups, name)
        local found = 0
        local count_ingredient_groups = #ingredient_groups
        for i = 1, count_ingredient_groups do
            if minetest.get_item_group(name, ingredient_groups[i]) ~= 0 then found = found + 1 end
        end
        return found == count_ingredient_groups
    end

    -- Next, resolve groups using the remaining items in the inventory
    if next(grouped_ingredients) ~= nil then
        local take
        for itemname, count in pairs(inv_index) do
            if count > 0 then
                -- groupname is the string as defined by recipe.
                --  e.g. group:dye,color_blue
                -- groups holds the group names split into a list
                --  ready to be passed to core.get_item_group()
                for groupname, groups in pairs(grouped_ingredients) do
                    if consumption_with_groups[groupname] > 0 and ingredient_groups_match_item(groups, itemname) then
                        take = math.min(count, consumption_with_groups[groupname])
                        consumption_with_groups[groupname] = consumption_with_groups[groupname] - take

                        assert(consumption_with_groups[groupname] >= 0)
                        consumption[itemname] = (consumption[itemname] or 0) + take

                        inv_index[itemname] = inv_index[itemname] - take
                        assert(inv_index[itemname] >= 0)
                    end
                end
            end
        end
    end

    -- Finally, check everything has been consumed
    for key, count in pairs(consumption_with_groups) do
        if count > 0 then return nil end
    end

    return consumption
end

local function has_room_for_output(list_output, index_output)
    local name
    local empty_count = 0
    for _, item in pairs(list_output) do
        if item:is_empty() then
            empty_count = empty_count + 1
        else
            name = item:get_name()
            if index_output[name] then index_output[name] = index_output[name] - item:get_free_space() end
        end
    end
    for _, count in pairs(index_output) do
        if count > 0 then empty_count = empty_count - 1 end
    end
    if empty_count < 0 then return false end

    return true
end

local function autocraft(inventory, craft)
    if not craft then return false end

    -- check if output and all replacements fit in dst
    local output = craft.output.item
    local out_items = count_index(craft.decremented_input)
    out_items[output:get_name()] = (out_items[output:get_name()] or 0) + output:get_count()

    if not has_room_for_output(inventory:get_list 'dst', out_items) then return false end

    -- check if we have enough material available
    local inv_index = count_index(inventory:get_list 'src')
    local consumption = calculate_consumption(inv_index, craft.consumption)
    if not consumption then return false end

    -- consume material
    for itemname, number in pairs(consumption) do
        -- We have to do that since remove_item does not work if count > stack_max
        for _ = 1, number do
            inventory:remove_item('src', ItemStack(itemname))
        end
    end

    -- craft the result into the dst inventory and add any "replacements" as well
    inventory:add_item('dst', output)
    local leftover
    for i = 1, 9 do
        leftover = inventory:add_item('dst', craft.decremented_input[i])
        if leftover and not leftover:is_empty() then
            minetest.log('warning', "[pipeworks] autocrafter didn't " .. 'calculate output space correctly.')
        end
    end
    return true
end

-- returns false to stop the timer, true to continue running
-- is started only from start_autocrafter(pos) after sanity checks and
-- recipe is cached
local function run_autocrafter(pos)
    local meta = minetest.get_meta(pos)
    local inventory = meta:get_inventory()
    local craft = get_craft(pos, inventory)
    local output_item = craft.output.item
    -- only use crafts that have an actual result
    if output_item:is_empty() then
        meta:set_string('infotext', S 'unconfigured Autocrafter: unknown recipe')
        return false
    end
    local continue = autocraft(inventory, craft)
    if not continue then return false end
    return true
end

-- note, that this function assumes allready being updated to virtual items
-- and doesn't handle recipes with stacksizes > 1
local function after_recipe_change(pos, inventory)
    local hash = minetest.hash_node_position(pos)
    local meta = minetest.get_meta(pos)
    autocrafterCache[hash] = nil
    -- if we emptied the grid, there's no point in keeping it running or cached
    if inventory:is_empty 'recipe' then
        inventory:set_stack('output', 1, '')
        return
    end
    local craft = get_craft(pos, inventory, hash)
    local output_item = craft.output.item
    local description, name = get_item_info(output_item)
    inventory:set_stack('output', 1, output_item)
    reserve_slots(pos, meta)
end

-- clean out unknown items and groups, which would be handled like unknown
-- items in the crafting grid
-- if minetest supports query by group one day, this might replace them
-- with a canonical version instead
local function normalize(item_list)
    for i = 1, #item_list do
        local name = item_list[i]
        if not minetest.registered_items[name] then item_list[i] = '' end
    end
    return item_list
end

local function on_output_change(pos, inventory, stack)
    if not stack then
        inventory:set_list('output', {})
        inventory:set_list('recipe', {})
    else
        local input = minetest.get_craft_recipe(stack:get_name())
        if not input.items or input.type ~= 'normal' then return end
        local items, width = normalize(input.items), input.width
        local item_idx, width_idx = 1, 1
        for i = 1, 9 do
            if width_idx <= width then
                inventory:set_stack('recipe', i, items[item_idx])
                item_idx = item_idx + 1
            else
                inventory:set_stack('recipe', i, ItemStack '')
            end
            width_idx = (width_idx < 3) and (width_idx + 1) or 1
        end
        -- we'll set the output slot in after_recipe_change to the actual
        -- result of the new recipe
    end
    after_recipe_change(pos, inventory)
end

-- returns false if we shouldn't bother attempting to start the timer again
-- after this
local function update_meta(pos, meta)
    reserve_slots(pos, meta)
    local fs = 'formspec_version[7]'
        .. 'size[11.4,10.5]'
        .. 'list[context;recipe;0.22,0.22;3,3;]'
        .. 'image[4,1.45;1,1;[combine:16x16^[noalpha^[colorize:#141318:255]'
        .. 'list[context;output;4,1.45;1,1;]'
        .. 'list[context;processor;4,2.7;1,1;]'
        .. 'list[context;dst;5.28,0.22;4,3;]'
        .. reserved_items_formspec(pos)
        .. 'list[context;src;0.22,4;9,1;]'
        .. pipeworks.fs_helpers.get_inv(5.5)
        .. 'listring[current_player;main]'
        .. 'listring[context;src]'
        .. 'listring[current_player;main]'
        .. 'listring[context;dst]'
        .. 'listring[current_player;main]'
    meta:set_string('formspec', fs)

    -- toggling the button doesn't quite call for running a recipe change check
    -- so instead we run a minimal version for infotext setting only
    -- this might be more written code, but actually executes less
    local output = meta:get_inventory():get_stack('output', 1)
    local processor = meta:get_inventory():get_stack('processor', 1)
    if output:is_empty() then -- doesn't matter if paused or not
        meta:set_string('infotext', S 'unconfigured Autocrafter')
        return false
    elseif processor:is_empty() then 
        meta:set_string("infotext", S 'No crafting processor.')
        return false
    end

    local description, name = get_item_info(output)
    local infotext = S("'@1' Autocrafter (@2)", description, name)

    meta:set_string('infotext', infotext)
    return true
end

local inv_cache = sbz_api.make_cache 'inv_cache' -- USE ONLY inv_cache.data, nothing else, as it wont get cleared that way
local list_cache = sbz_api.make_cache('list_cache', 0, true)

-- crafting processors & stats
-- might want to introduce a register_crafting_processor function sometime
local processor_stats_map = {
    ["sbz_resources:simple_crafting_processor"] = { crafts = 1, power = 10 },
    ["sbz_resources:quick_crafting_processor"] = { crafts = 2, power = 25 },
    ["sbz_resources:fast_crafting_processor"] = { crafts = 4, power = 50 },
    ["sbz_resources:accelerated_silicon_crafting_processor"] = { crafts = 8, power = 100 },
    ["sbz_resources:nuclear_crafting_processor"] = { crafts = 16, power = 175 },
}

minetest.register_node('pipeworks:autocrafter', {
    description = S 'Autocrafter',
    drawtype = 'normal',
    tiles = { 'autocrafter.png' },
    groups = {
        matter = 2,
        snappy = 3,
        tubedevice = 1,
        tubedevice_receiver = 1,
        dig_generic = 1,
        axey = 1,
        handy = 1,
        pickaxey = 1,
        pipe_connects = 1,
        pipe_conducts = 1,
        sbz_machine = 1,
    },
    is_ground_content = false,
    tube = {
        insert_object = function(pos, node, stack, direction)
            local slots = get_reserved_slots_or_reserve_them(pos)
            if slots == nil then return stack end
            local stackname = stack:get_name()
            if not slots[stackname] then return stack end

            local inv = inv_cache.data[h(pos)]
            if not inv then
                inv_cache.data[h(pos)] = core.get_meta(pos):get_inventory()
                inv = inv_cache.data[h(pos)]
            end

            local srclist = list_cache.data[h(pos)]
            if not srclist then
                list_cache.data[h(pos)] = inv:get_list 'src'
                srclist = list_cache.data[h(pos)]
            end

            local stack_max = stack:get_stack_max()

            local that_stack, leftover, new_count
            for i = 1, 9 do
                if slots[i] == stackname then
                    that_stack = srclist[i]
                    new_count = that_stack:get_count() + stack:get_count()
                    if that_stack:get_name() == '' then that_stack:set_name(stackname) end
                    -- BUGFIX #167
                    -- that_stack will still be empty if it's a tool for some reason?
                    -- weeird
                    if that_stack:get_name() == stackname or that_stack:get_name() == '' then
                        leftover = math.max(0, new_count - stack_max)
                        that_stack:set_count(new_count - leftover)
                        srclist[i] = that_stack
                        stack:set_count(leftover)
                        stack:set_name(stackname)
                        if leftover == 0 then break end
                    end
                end
            end
            inv:set_list('src', srclist)
            return stack
        end,
        can_insert = function(pos, node, stack, direction)
            local meta = minetest.get_meta(pos)
            local inv = meta:get_inventory()
            local slots = get_reserved_slots_or_reserve_them(pos)
            if slots == nil then return false end
            if not slots[stack:get_name()] then return false end
            -- next up, check if we actually can insert
            local compare_stack = ItemStack(stack)
            for i = 1, 9 do
                if slots[i] == stack:get_name() then
                    local that_stack = inv:get_stack('src', i)
                    local leftover = that_stack:add_item(stack):get_count()
                    compare_stack:set_count(leftover)
                end
            end

            return compare_stack:get_count() == 0
        end,
        input_inventory = 'dst',
        connect_sides = {
            left = 1,
            right = 1,
            front = 1,
            back = 1,
            top = 1,
            bottom = 1,
        },
        ignore_allow_metadata_inventory_take = true,
    },
    on_construct = function(pos)
        local meta = minetest.get_meta(pos)
        local inv = meta:get_inventory()
        inv:set_size('src', 9)
        inv:set_size('recipe', 3 * 3)
        inv:set_size('dst', 4 * 3)
        inv:set_size('output', 1)
        inv:set_size('processor', 1)
        update_meta(pos, meta)
    end,
    on_rightclick = function(pos)
        update_meta(pos, minetest.get_meta(pos))
    end,
    can_dig = function(pos, player)
        local meta = minetest.get_meta(pos)
        local inv = meta:get_inventory()
        return (inv:is_empty 'src' and inv:is_empty 'dst' and inv:is_empty 'processor')
    end,
    after_place_node = pipeworks.scan_for_tube_objects,
    after_dig_node = function(pos)
        pipeworks.scan_for_tube_objects(pos)
    end,
    on_destruct = function(pos)
        autocrafterCache[minetest.hash_node_position(pos)] = nil
    end,
    allow_metadata_inventory_put = function(pos, listname, index, stack, player)
        list_cache.data[h(pos)] = nil
        if not pipeworks.may_configure(pos, player) then return 0 end
        local inv = minetest.get_meta(pos):get_inventory()
        if listname == 'recipe' then
            stack:set_count(1)
            inv:set_stack(listname, index, stack)
            after_recipe_change(pos, inv)
            return 0
        elseif listname == 'output' then
            on_output_change(pos, inv, stack)
            return 0
        elseif listname == 'src' then
            local meta = minetest.get_meta(pos)
            local reserved_slot = get_reserved_slots_or_reserve_them(pos)
            if not reserved_slot then return stack:get_count() end
            local stackname = stack:get_name()
            if stackname ~= reserved_slot[index] then return 0 end
        end
        return stack:get_count()
    end,
    allow_metadata_inventory_take = function(pos, listname, index, stack, player)
        list_cache.data[h(pos)] = nil
        if not pipeworks.may_configure(pos, player) then
            minetest.log(
                'action',
                string.format(
                    '%s attempted to take from ' .. 'autocrafter at %s',
                    player:get_player_name(),
                    minetest.pos_to_string(pos)
                )
            )
            return 0
        end
        local inv = minetest.get_meta(pos):get_inventory()
        if listname == 'recipe' then
            inv:set_stack(listname, index, ItemStack '')
            after_recipe_change(pos, inv)
            return 0
        elseif listname == 'output' then
            on_output_change(pos, inv, nil)
            return 0
        end
        return stack:get_count()
    end,
    allow_metadata_inventory_move = function(pos, from_list, from_index, to_list, to_index, count, player)
        list_cache.data[h(pos)] = nil
        if not pipeworks.may_configure(pos, player) then return 0 end
        local inv = minetest.get_meta(pos):get_inventory()
        local stack = inv:get_stack(from_list, from_index)

        if to_list == 'output' then
            on_output_change(pos, inv, stack)
            return 0
        elseif from_list == 'output' then
            on_output_change(pos, inv, nil)
            if to_list ~= 'recipe' then return 0 end -- else fall through to recipe list handling
        end

        if from_list == 'recipe' or to_list == 'recipe' then
            if from_list == 'recipe' then inv:set_stack(from_list, from_index, ItemStack '') end
            if to_list == 'recipe' then
                stack:set_count(1)
                inv:set_stack(to_list, to_index, stack)
            end
            after_recipe_change(pos, inv)
            return 0
        end

        if to_list == 'src' then
            local meta = minetest.get_meta(pos)
            local reserved_slot = get_reserved_slots_or_reserve_them(pos)
            if not reserved_slot then return stack:get_count() end
            local stackname = stack:get_name()
            if stackname ~= reserved_slot[to_index] then return 0 end
        end
        return count
    end,
    info_extra = 'Requires a crafting processor to work.',
    action = function(pos, node, meta, supply, demand)
        local inv = meta:get_inventory()
        local processor_stack = inv:get_stack("processor", 1)

        if processor_stack:is_empty() then
            meta:set_string('infotext', 'No crafting processor.')
            return 0
        end

        local item_name = processor_stack:get_name()
        local stats = processor_stats_map[item_name]

        if not stats then
            meta:set_string('infotext', 'This item is not a crafting processor.')
            return 0
        end

        local max_crafts = stats.crafts
        local power_demand = stats.power

        if supply < power_demand then
            meta:set_string('infotext', 'Not enough power (' .. supply .. '/' .. power_demand .. ')')
            return 0
        end

        local gi
        local broken = false
        for i = 1, max_crafts do
            gi = i
            if not run_autocrafter(pos) then
                broken = true
                break
            end
        end

        if not gi or (gi == 1 and broken) then
            meta:set_string('infotext', "Can't craft (check recipe/output)")
            return 0
        end

        local crafts_succeeded = gi
        if broken then
            crafts_succeeded = gi - 1 -- last craft failed
        end

        local usage_percent = 0
        if max_crafts > 0 then
            usage_percent = math.floor((crafts_succeeded / max_crafts) * 100)
        end

        local infotext = string.format(
            "Active, consuming %d power. | CPU Usage: %d%% (%d/%d)",
            power_demand,
            usage_percent,
            crafts_succeeded,
            max_crafts
        )
        meta:set_string('infotext', infotext)

        return power_demand
    end,
    on_logic_send = function(pos, msg, from_pos)
        local ok, faulty = libox.type_check(msg, {
            { libox.type 'string', libox.type 'string', libox.type 'string' },
            { libox.type 'string', libox.type 'string', libox.type 'string' },
            { libox.type 'string', libox.type 'string', libox.type 'string' },
        })
        if not ok then return end

        local list = {}
        -- validate
        for y = 1, 3 do
            for x = 1, 3 do
                local target = ItemStack(msg[y][x])
                if not target then return end
                if not target:is_known() then return end
                target:set_count(1)
                list[#list + 1] = target
            end
        end

        local meta = minetest.get_meta(pos)
        local inv = meta:get_inventory()
        inv:set_list('recipe', list)
        after_recipe_change(pos, inv)
        update_meta(pos, meta)
    end,
})

minetest.register_craft {
    output = 'pipeworks:autocrafter',
    recipe = {
        { 'sbz_resources:robotic_arm', 'sbz_resources:robotic_arm', 'sbz_resources:robotic_arm' },
        { 'sbz_resources:emittrium_circuit', 'sbz_resources:emittrium_circuit', 'sbz_resources:emittrium_circuit' },
        { 'sbz_chem:titanium_alloy_ingot', 'sbz_meteorites:neutronium', 'sbz_chem:titanium_alloy_ingot' },
    },
}
