-- Plantlife library mod by Vanessa Ezekowitz
-- 2013-01-00
--
-- License:  WTFPL

-- Various settings - most of these probably won't need to be changed

plantlife_seed_diff = 329	-- needs to be global so other mods can see it

local plantlife_debug = true  -- ...unless you want the modpack to spam the console ;-)

local perlin_octaves = 3
local perlin_persistence = 0.6
local perlin_scale = 100

local plantlife_limit = 0.1 -- compared against perlin noise.  lower = more abundant

-- Local functions

math.randomseed(os.time())

local dbg = function(s)
	if plantlife_debug then
		print("[Plantlife] " .. s)
	end
end

local is_node_loaded = function(node_pos)
	n = minetest.env:get_node_or_nil(node_pos)
	if (n == nil) or (n.name == "ignore") then
		return false
	end
	return true
end

-- The spawning ABM

spawn_on_surfaces = function(sdelay, splant, sradius, schance, ssurface, savoid, seed_diff, lightmin, lightmax, nneighbors, ocount, facedir, depthmax, altmin, altmax, sbiome, sbiomesize, sbiomecount)
	if seed_diff == nil then seed_diff = 0 end
	if lightmin == nil then lightmin = 0 end
	if lightmax == nil then lightmax = LIGHT_MAX end
	if nneighbors == nil then nneighbors = ssurface end
	if ocount == nil then ocount = -1 end
	if depthmax == nil then depthmax = 1 end
	if altmin == nil then altmin = -31000 end
	if altmax == nil then altmax = 31000 end
	if sbiome == nil then sbiome = "" end
	if sbiomesize == nil then sbiomesize = 0 end
	if sbiomecount == nil then sbiomecount = 1 end
	minetest.register_abm({
		nodenames = { ssurface },
		interval = sdelay,
		chance = schance,
		neighbors = nneighbors,
		action = function(pos, node, active_object_count, active_object_count_wider)
			local p_top = { x = pos.x, y = pos.y + 1, z = pos.z }	
			local n_top = minetest.env:get_node(p_top)
			local perlin = minetest.env:get_perlin(seed_diff, perlin_octaves, perlin_persistence, perlin_scale )
			local noise = perlin:get2d({x=p_top.x, y=p_top.z})
			if noise > plantlife_limit and n_top.name == "air" and is_node_loaded(p_top) then
				local n_light = minetest.env:get_node_light(p_top, nil)
				if minetest.env:find_node_near(p_top, sradius + math.random(-1.5,2), savoid) == nil
				  and n_light >= lightmin
				  and n_light <= lightmax
				  and 
					(table.getn(minetest.env:find_nodes_in_area({x=pos.x-1, y=pos.y, z=pos.z-1}, {x=pos.x+1, y=pos.y, z=pos.z+1}, nneighbors)) > ocount 
					  or ocount == -1)
				  and 
					(table.getn(minetest.env:find_nodes_in_area({x=pos.x-sbiomesize, y=pos.y-1, z=pos.z-sbiomesize}, {x=pos.x+sbiomesize, y=pos.y+1, z=pos.z+sbiomesize}, sbiome)) >= sbiomecount
					  or sbiome == "")
				  and pos.y >= altmin
				  and pos.y <= altmax
					then
						local walldir = plant_valid_wall(p_top)
						if splant == "poisonivy:seedling" and walldir ~= nil then
							dbg("Spawn: poisonivy:climbing at "..dump(p_top).." on "..ssurface)
							minetest.env:add_node(p_top, { name = "poisonivy:climbing", param2 = walldir })
						else
							local deepnode = minetest.env:get_node({ x = pos.x, y = pos.y-depthmax-1, z = pos.z }).name
							if (ssurface ~= "default:water_source")
								or (ssurface == "default:water_source"
								and deepnode ~= "default:water_source") then
								dbg("Spawn: "..splant.." at "..dump(p_top).." on "..ssurface)
								minetest.env:add_node(p_top, { name = splant, param2 = facedir })
							end
						end
				end
			end
		end
	})
end

-- The growing ABM

grow_plants = function(gdelay, gchance, gplant, gresult, dry_early_node, grow_nodes, facedir, need_wall, grow_vertically, height_limit, ground_nodes, grow_function, seed_diff)
	if need_wall ~= true then need_wall = false end
	if grow_vertically ~= true then grow_vertically = false end
	if height_limit == nil then height_limit = 62000 end
	if ground_node == nil then ground_nodes = { "default:dirt_with_grass" } end
	minetest.register_abm({
		nodenames = { gplant },
		interval = gdelay,
		chance = gchance,
		action = function(pos, node, active_object_count, active_object_count_wider)
			local p_top = {x=pos.x, y=pos.y+1, z=pos.z}
			local p_bot = {x=pos.x, y=pos.y-1, z=pos.z}
			local n_top = minetest.env:get_node(p_top)
			local n_bot = minetest.env:get_node(p_bot)
			local groundnode = minetest.env:get_node({x=pos.x, y=pos.y-height_limit, z=pos.z})
			if grow_function == nil then
				if string.find(dump(grow_nodes), n_bot.name) ~= nil and n_top.name == "air" then
					if grow_vertically then
						if find_first_node(pos, height_limit, ground_nodes) ~= nil then
							if need_wall then
								local walldir=plant_valid_wall(p_top)
								if walldir ~= nil then
									dbg("Grow: "..gplant.." upwards to ("..dump(p_top)..") on wall "..walldir)
									minetest.env:add_node(p_top, { name = gplant, param2 = walldir })
								end
							else
								dbg("Grow: "..gplant.." upwards to ("..dump(p_top)..")")
								minetest.env:add_node(p_top, { name = gplant })
							end
						end

					-- corner case for changing short junglegrass to dry shrub in desert
					elseif n_bot.name == dry_early_node and gplant == "junglegrass:short" then
						dbg("Die: "..gplant.." becomes default:dry_shrub at ("..dump(pos)..")")
						minetest.env:add_node(pos, { name = "default:dry_shrub" })

					elseif gresult == nil then
						dbg("Die: "..gplant.." at ("..dump(pos)..")")
						minetest.env:remove_node(pos)

					elseif gresult ~= nil then
						dbg("Grow: "..gplant.." becomes "..gresult.." at ("..dump(pos)..")")
						if facedir == nil then
							minetest.env:add_node(pos, { name = gresult })
						else
							minetest.env:add_node(pos, { name = gresult, param2 = facedir })
						end
					end
				end
			else
				if seed_diff == nil then seed_diff = 0 end
				local perlin = minetest.env:get_perlin(seed_diff, perlin_octaves, perlin_persistence, perlin_scale )
				local noise = perlin:get2d({x=pos.x, y=pos.z})
				dbg("Want to execute "..grow_function.."("..dump(pos)..","..noise..")")
				assert(loadstring(grow_function.."("..dump(pos)..","..noise..")"))()
			end
		end
	})
end

-- function to decide if a node has a wall that's in verticals_list{}
-- returns wall direction of valid node, or nil if invalid.

plant_valid_wall = function(wallpos)
	local walldir = nil
	local verts = dump(verticals_list)

	local testpos = { x = wallpos.x-1, y = wallpos.y, z = wallpos.z   }
	if string.find(verts, minetest.env:get_node(testpos).name) ~= nil then walldir=3 end

	local testpos = { x = wallpos.x+1, y = wallpos.y, z = wallpos.z   }
	if string.find(verts, minetest.env:get_node(testpos).name) ~= nil then walldir=2 end

	local testpos = { x = wallpos.x  , y = wallpos.y, z = wallpos.z-1 }
	if string.find(verts, minetest.env:get_node(testpos).name) ~= nil then walldir=5 end

	local testpos = { x = wallpos.x  , y = wallpos.y, z = wallpos.z+1 }
	if string.find(verts, minetest.env:get_node(testpos).name) ~= nil then walldir=4 end

	return walldir
end

-- Function to search straight down from (pos) to find first node in match list.

find_first_node = function(pos, height_limit, nodelist)
	for i = 1, height_limit do
		n = minetest.env:get_node({x=pos.x, y=pos.y-i, z=pos.z})
		if string.find(dump(nodelist),n.name) ~= nil then
			return n.name
		end
	end
	return nil
end

print("[Plantlife] Loaded!")