--[[

  Nether mod for minetest

  Copyright (C) 2013 PilzAdam

  Permission to use, copy, modify, and/or distribute this software for
  any purpose with or without fee is hereby granted, provided that the
  above copyright notice and this permission notice appear in all copies.

  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
  WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
  WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR
  BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES
  OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
  ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
  SOFTWARE.

]]--

-- Global Nether namespace
nether = {}
nether.path = minetest.get_modpath("nether")

-- Settings
nether.DEPTH             = -5000
nether.FASTTRAVEL_FACTOR =     8 -- 10 could be better value for Minetest, since there's no sprint, but ex-Minecraft players will be mathing for 8


-- Load files
dofile(nether.path .. "/portal_api.lua")
dofile(nether.path .. "/nodes.lua")
dofile(nether.path .. "/mapgen.lua")


-- Portals are ignited by right-clicking with a mese crystal fragment
nether.register_portal_ignition_item("default:mese_crystal_fragment")


-- Use the Portal API to add a portal type which goes to the Nether
-- See portal_api.txt for documentation
nether.register_portal("nether_portal", {
	shape               = nether.PortalShape_Traditional,
	frame_node_name     = "default:obsidian",
	wormhole_node_name  = "nether:portal",
	wormhole_node_color = 0,
	sound_ambient       = "nether_portal_hum",
	sound_ignite        = "",
	sound_extinguish    = "",
	sound_teleport      = "",

	within_realm = function(pos) -- return true if pos is inside the Nether
		return pos.y < nether.DEPTH
	end,

	find_realm_anchorPos = function(surface_pos)
		-- divide x and z by a factor of 8 to implement Nether fast-travel
		local destination_pos = vector.divide(surface_pos, nether.FASTTRAVEL_FACTOR)
		destination_pos.x = math.floor(0.5 + destination_pos.x) -- round to int
		destination_pos.z = math.floor(0.5 + destination_pos.z) -- round to int

		local start_y = nether.DEPTH - math.random(500, 1500) -- Search start
		destination_pos.y = nether.find_nether_ground_y(destination_pos.x, destination_pos.z, start_y)
		return destination_pos
	end,

	find_surface_anchorPos = function(realm_pos)
		-- A portal definition doesn't normally need to provide a find_surface_anchorPos() function,
		-- since find_surface_target_y() will be used by default, but Nether portals also scale position
		-- to create fast-travel:

		-- Multiply x and z by a factor of 8 to implement Nether fast-travel
		local destination_pos = vector.multiply(realm_pos, nether.FASTTRAVEL_FACTOR)
		destination_pos.x = math.min(30900, math.max(-30900, destination_pos.x)) -- clip to world boundary
		destination_pos.z = math.min(30900, math.max(-30900, destination_pos.z)) -- clip to world boundary

		destination_pos.y = nether.find_surface_target_y(destination_pos.x, destination_pos.z, "nether_portal")
		return destination_pos
	end
})