local api = blockgame.crafting

-- pummeling is heavily based on nodecore by Warr1024 (both the mechanic itself and the code here implementing it).

local pummel_recipes = {}

function api.register_pummel_recipe (def)
	local def = def or {}

	-- TODO: require `def.name` to be specified and unique.
	def.label = def.label or "unlabeled pummel recipe"

	-- TODO: throw errors when these defs are invalid instead of just returning.
	if not def.used then return false end
	if not def.target then return false end
	if not type(def.on_success) == "function" then return false end

	def["type"] = "pummel"

	table.insert(pummel_recipes, def)
	table.insert(api.registered_recipes, def)
end

-- TODO: extract this function into general api
local function item_matches (nodename, options)
	return blockgame.any(options, function (option)
		if nodename == option then return true end
		if blockgame.starts_with(option, "group:") then
			local group = string.sub(option, 7)
			return minetest.get_item_group(nodename, group) > 0
		end
		return false
	end)
end

-- TODO: add support for pummel recipes using groups instead of just specific node names.
function api.pummel_check (pos, used, target_node)
	for _, def in pairs(pummel_recipes) do
		if item_matches(used, def.used) and item_matches(target_node.name, def.target) then
			if type(def.check) == "function" and not def.check(pos, used, target_node) then
				return false
			end
			def.on_success(pos, used, target_node)
			return true
		end
	end
end


local pummeling = {}

-- NOTE: might wanna change this to somehow store pummels per-node instead of per-player?
blockgame.register_on_dignode(function (_, _, digger)
	if not (digger and digger:is_player()) then return end
	pummeling[digger:get_player_name()] = nil
end)

blockgame.register_on_punchnode(function (pos, node, puncher, pointed)
	if (not puncher:is_player()) or puncher:get_player_control().sneak then return end
	local player_name = puncher:get_player_name()
	-- if not minetest.interact(player_name) then return end
	if not minetest.check_player_privs(player_name, "interact") then return end

	node = node or minetest.get_node(pos)
	local node_def = minetest.registered_items[node.name] or {}
	if not node_def.pointable then return end

	local wield = puncher:get_wielded_item()
	local now = minetest.get_us_time() / 1000000

	local pummel_data = {
		action = "pummel",
		crafter = puncher,
		crafter_name = player_name,
		pos = pos,
		pointed = pointed,
		node = node,
		node_def = node_def,
		start = now,
		wield = wield:get_name() .. " " .. wield:get_count(),
		count = 0,
	}

	local old_data = pummeling[player_name]
	local hash = minetest.hash_node_position
	if old_data and hash(old_data.pos) == hash(pummel_data.pos)
		and hash(old_data.pointed.above) == hash(pummel_data.pointed.above)
		and hash(old_data.pointed.under) == hash(pummel_data.pointed.under)
		and old_data.wield == pummel_data.wield
		and old_data.last >= (now - 3)
		then pummel_data = old_data
	end

	pummel_data.count = pummel_data.count + 1
	pummel_data.last = now
	pummel_data.duration = now - pummel_data.start - 1
	pummeling[player_name] = pummel_data

	if pummel_data.count < 2 then return end

	if api.pummel_check(pos, wield:get_name(), minetest.get_node(pointed.under)) then
		pummeling[player_name] = nil
	end
end)