-- advtrains track map generator
-- Usage: lua main.lua path/to/world

-- Viewport maximum coordinate in all directions
local maxc = 5000

-- embed an image called "world.png"
local wimg = true
-- image file resolution (not world resolution!)
local wimresx = 3000
local wimresy = 3000
-- one pixel is ... nodes
local wimscale = 4

datapath = (arg[1] or "").."/"


--Constant for maximum connection value/division of the circle
AT_CMAX = 16

advtrains = {}
minetest = {}
core = minetest

--table for track nodes/connections
trackconns = {}

-- math library seems to be missing this function
math.hypot = function(a,b) return math.sqrt(a*a + b*b) end

-- need to declare this for trackdefs
function attrans(str) return str end

-- pos to string
local function pts(pos)
	return pos.x .. "," .. pos.y .. "," .. pos.z
end

--Advtrains dump (special treatment of pos and sigd)
function atdump(t, intend)
	local str
	if type(t)=="table" then
		if t.x and t.y and t.z then
			str=minetest.pos_to_string(t)
		elseif t.p and t.s then -- interlocking sigd
			str="S["..minetest.pos_to_string(t.p).."/"..t.s.."]"
		else
			str="{"
			local intd = (intend or "") .. "  "
			for k,v in pairs(t) do
				if type(k)~="string" or not string.match(k, "^path[_]?") then
					-- do not print anything path-related
					str = str .. "\n" .. intd .. atdump(k, intd) .. " = " ..atdump(v, intd)
				end
			end
			str = str .. "\n" .. (intend or "") .. "}"
		end
	elseif type(t)=="boolean" then
		if t then
			str="true"
		else
			str="false"
		end
	elseif type(t)=="function" then
		str="<function>"
	elseif type(t)=="userdata" then
		str="<userdata>"
	else
		str=""..t
	end
	return str
end

dofile("vector.lua")
dofile("serialize.lua")
dofile("helpers.lua")
dofile("tracks.lua")
dofile("track_defs.lua")

dofile("nodedb.lua")


-- Load saves
local file, err = io.open(datapath.."advtrains", "r")
local tbl = minetest.deserialize(file:read("*a"))
if type(tbl) ~= "table" then
	error("not a table")
end
if tbl.version then
	
	advtrains.ndb.load_data(tbl.ndb)
	
else
	error("Incompatible save format!")
end
file:close()

-- open svg file

local svgfile = io.open(datapath.."out.svg", "w")

svgfile:write([[
<?xml version="1.0" standalone="no" ?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20010904//EN"
  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
<svg width="1024" height="800" xmlns="http://www.w3.org/2000/svg"
  xmlns:xlink="http://www.w3.org/1999/xlink" ]])


svgfile:write('viewBox="'..(-maxc)..' '..(-maxc)..' '..(2*maxc)..' '..(2*maxc)..'" >')


svgfile:write([[
<circle cx="0" cy="0" r="2" stroke="red" stroke-width="1" />
]])

if wimg then
	local wimx = -(wimresx*wimscale/2)
	local wimy = -(wimresy*wimscale/2)
	local wimw = wimresx*wimscale
	local wimh = wimresy*wimscale
	
	svgfile:write('<image xlink:href="world.png" x="'..wimx..'" y="'..wimy..'" height="'..wimh..'px" width="'..wimw..'px"/>')
end

local function writec(text)
	--print("\n"..text)
	svgfile:write("<!-- " .. text .. " -->\n")
end


-- everything set up. Start generating an SVG
-- All nodes that have been fit into a polyline are removed from the NDB, in order to not draw them again.

-- "Restart points" for the breadth-first traverser (set when more than 2 conns present)
-- {pos = <position>, connid = <int>, conn = <conndef>}
-- Note that the node at "pos" is already deleted from the NDB at the time of recall, therefore "conn" is specified
local bfs_rsp = {}

local ndb_nodes_handled = 0

-- Points of the current polyline. Inserted as xyz vectors, maybe we'll use the y value one day
local current_polyline = {}

-- Traverser function from interlocking, highly modified
local function gen_rsp_polyline(rsp)

	-- trick a bit
	local pos, connid, conns = rsp.pos, 1, {rsp.conn}
	current_polyline[#current_polyline+1] = pos
	
	while true do
		local adj_pos, adj_connid, conn_idx, nextrail_y, next_conns = advtrains.get_adjacent_rail(pos, conns, connid)
		if not adj_pos then
			return
		end
		-- continue traversing
		local conn_mainbranch
		for nconnid, nconn in ipairs(next_conns) do
			if adj_connid ~= nconnid then
				if not conn_mainbranch then
					--use the first one found to continue
					conn_mainbranch = nconnid
					--writec(nconnid.." nconn mainbranch")
				else
					-- insert bfs reminders for other conns
					table.insert(bfs_rsp, {pos = adj_pos, connid = nconnid, conn = nconn})
					--writec(nconnid.." nconn bfs")
				end
			end
		end
		
		-- save in polyline and delete from ndb
		--writec("Saved pos: "..pts(adj_pos).." mainbranch cont "..conn_mainbranch.." nextconns "..atdump(next_conns))
		current_polyline[#current_polyline+1] = adj_pos
		advtrains.ndb.clear(adj_pos)
		ndb_nodes_handled = ndb_nodes_handled + 1
		
		pos, connid, conns = adj_pos, conn_mainbranch, next_conns
		
	end
end

plcnt = 0

local function polyline_write(pl)
	local str = {'<polyline style="fill:none;stroke:black;stroke-width:1" points="'}
	
	local i
	local e
	local lastldir = {x=0, y=0}
	for i=1,#pl do
		e = pl[i]
		-- Note that we mirror y, so positive z is up
		table.insert(str, e.x .. "," .. -(e.z) .. " ")
	end
	
	table.insert(str, '" />\n')
	
	svgfile:write(table.concat(str))
	plcnt = plcnt + 1
end


-- while there are entries in the nodedb
-- 1. find a starting point
	local stpos, conns = advtrains.ndb.mapper_find_starting_point()
while stpos do
	
	writec("Restart at position "..pts(stpos))
	for connid, conn in ipairs(conns) do
		table.insert(bfs_rsp, {pos = stpos, connid = connid, conn = conn})
	end
	advtrains.ndb.clear(stpos)
	
	-- 2. while there are BFS entries
	while #bfs_rsp > 0 do
		-- make polylines
		local current_rsp = bfs_rsp[#bfs_rsp]
		bfs_rsp[#bfs_rsp] = nil
		--print("Starting polyline at "..pts(current_rsp.pos).."/"..current_rsp.connid)
		
		
		current_polyline = {}
		
		gen_rsp_polyline(current_rsp)
		
		polyline_write(current_polyline)
		
		io.write("Progress ", ndb_nodes_handled, "+", ndb_nodes_notrack, "/", ndb_nodes_total, "=", math.floor(((ndb_nodes_handled+ndb_nodes_notrack)/ndb_nodes_total)*100), "%\r")
	end
	stpos, conns = advtrains.ndb.mapper_find_starting_point()
end

svgfile:write("</svg>")
svgfile:close()

print("\nWrote",plcnt,"polylines. Processed", ndb_nodes_handled, "track,",ndb_nodes_notrack, "non-track nodes out of", ndb_nodes_total)