--nothing--
local S = minetest.get_translator("nc_sky_isgen")
local grass = "nc_terrain:dirt_with_grass"
local dirt = "nc_terrain:dirt"
local tree = "nc_tree:eggcorn_planted"
local stone = "nc_terrain:stone"
local queue = {}
local cooldown = 120
local cooldowns = {}

local function maxval(octaves,persistence,scale)
  local m = 1
  local poc = 1
  if octaves > 1 then
    for n=2,octaves do
      poc = poc*persistence
      m=m+poc
    end
  end
  return scale/m
end

local function dist(x1,y1,z1, x2,y2,z2)
  local x,y,z = x2-x1, y2-y1, z2-z1
  return (x*x+y*y+z*z)^0.5
end

local function cosify(x)
  return 1-math.cos(x*math.pi/2)
end

local pers = 0.9
local oct = 4

local noise = PerlinNoise{
  scale = maxval(oct,pers,32),
  spread = {x=64,y=64,z=64},
  seed=1297,
  octaves = oct,
  persistence = pers,
  lacunarity = 2,
  flags = "eased"
}

local function island(pos,r)
  local x,y,z = pos.x,pos.y,pos.z
  minetest.emerge_area({x=x-r,y=y-r,z=z-r},{x=x+r,y=y+r,z=z+r},function(bp,act,crem)
    if crem > 0 then
      return
    end
    local n = 0
    local c = 0
    local cm = (r*2+1)^3
    local function geto(x1,y1,z1,n)
      local r1 = 48+n*2-1
      local dista = dist(0,0,0,x1,y1*3,z1)
      local m = math.max(0,1-dista/r1)
      local r2 = -r1
      if y1 <= 0 and y1 >= r2 then
        local r3 = (1-math.sin(y1/r2*math.pi/2))*r1
        local distb = dist(0,y1,0,x1,y1,z1)
        local m2 = math.max(0,1-distb/r3)
        m = math.max(m2,m)
      end
      return cosify(m)
    end
    local grasses = {}
    local stones = {}
    for x=-r,r do
      for z=-r,r do
        for y=-r,r do
          local xx,yy,zz = pos.x+x,pos.y+y,pos.z+z
          local ppos = {x=xx,y=yy,z=zz}
          local o,o2 = geto(x,y,z,noise:get_3d(ppos)),geto(x,y+1,z,noise:get_3d({x=xx,y=yy+1,z=zz}))
          local oc = (o > 0.4)
          local oc2 = o2 > 0.4
          local og = (o > 0.5) and o2 > 0.4
          if oc then
            n=n+1
            local nam = dirt
            if not og and not oc2 then
              nam = grass
              table.insert(grasses,ppos)
            end
            if og then
              nam = stone
              table.insert(stones,ppos)
            end
            minetest.set_node(ppos,{name=nam})
          else
            n=n+0.01
          end
          if n > 1000 then
            n=0
            --coroutine.yield()
          end
        end
      end
    end
    for n=1,24 do
      if #stones > 1 then
        local n = math.random(1,#stones)
        local v = table.remove(stones,n)
        minetest.set_node(v,{name="nc_crystal:ore"})
      end
      if #stones > 1 then
        local n = math.random(1,#stones)
        local v = table.remove(stones,n)
        minetest.set_node(v,{name="nc_lux:stone"})
      end
    end
    for n=1,8 do
      if #grasses > 1 then
        local n = math.random(1,#grasses)
        local v = table.remove(grasses,n)
        minetest.set_node(v,{name=tree})
        local meta = minetest.get_meta(v)
        meta:set_float("growth",5000)
      end
    end
  end)
end
local f,abs = math.floor, math.abs
local function spawn_island(name,pos)
  local ref = minetest.get_player_by_name(name)
  pos = {x=f(pos.x),y=f(pos.y),z=f(pos.z)}
  island(pos,48,name)
  ref:set_pos({x=pos.x,y=pos.y+256,z=pos.z})
end
local store = minetest.get_mod_storage()
local players = minetest.deserialize(store:get_string("players")) or {}
local cells = minetest.deserialize(store:get_string("cells")) or {}
local function save() 
  store:set_string("players",minetest.serialize(players))
  store:set_string("cells",minetest.serialize(cells))
end
do
  local c = cells
  cells = {}
  for k,v in pairs(c) do
    if v.island then
      if v.valid and not v.name or v.name == "" then
        table.insert(cells,{pos=v.islandpos,valid=v.valid})
      end
    else
      table.insert(cells,v)
    end
  end

  local p = players
  players = {}
  for k,v in pairs(p) do
    players[k] = {pos=v.islandpos or v.pos, valid = v.valid}
  end
  save()
end

local air_c = minetest.get_content_id("air")
local ignore_c = minetest.get_content_id("ignore")

local function island_range(x,y,z)
  return {x=x-64,y=y-64,z=z-64},{x=x+64,y=y+64,z=z+64}
end
local function checkpos(x,y,z)
  local vm = VoxelManip(island_range(x,y,z))
  local emi,ema = vm:get_emerged_area()
  local dat = vm:get_data()
  local ar = VoxelArea:new{MinEdge=emi,MaxEdge=ema}
  for x = x-32,x+32 do
    for y = y-32,y+32 do
      for z = z-32,z+32 do
        local d = dat[ar:index(x,y,z)]
        if d ~= air_c and d ~= ignore_c then
          return false
        end
      end
    end
  end
  return true
end


local function intersect(a,b)
  local ap1,ap2 = a[1],a[2]
  local bp1,bp2 = b[1],b[2]
  local ax1,ay1,az1 = ap1.x,ap1.y,ap1.z
  local ax2,ay2,az2 = ap2.x,ap2.y,ap2.z
  local bx1,by1,bz1 = bp1.x,bp1.y,bp1.z
  local bx2,by2,bz2 = bp2.x,bp2.y,bp2.z

	return
		ax1 <= bx2 and
		ax2 >= bx1 and
		ay1 <= by2 and
		ay2 >= by1 and
		az1 <= bz2 and
		az2 >= bz1
end

local function get_standing_island(name)
  local ref = minetest.get_player_by_name(name)
  local pos = ref:get_pos()
  local islands = {}
  for k,v in pairs(cells) do
    if intersect({island_range(v.pos.x,v.pos.y,v.pos.z)},{pos,pos}) then
      table.insert(islands,{pos=v.pos,owner=nil,valid = not not v.valid,t=cells,k=k})
    end
  end
  for k,v in pairs(players) do
    if intersect({island_range(v.pos.x,v.pos.y,v.pos.z)},{pos,pos}) then
      table.insert(islands,{pos=v.pos,owner=k,valid = not not v.valid,t=players,k=k})
    end
  end
  if #islands == 0 then
    return
  end
  local closesti = table.remove(islands)
  local closestl = vector.length(vector.subtract(closesti.pos,pos))
  while #islands > 0 do
    local isl = table.remove(islands)
    local l = vector.length(vector.subtract(isl.pos,pos))
    if l < closestl then
      closesti = isl
      closestl = l
    end
  end
  return closesti
end

local function gen_island_pos(name)
  local x,y,z = 0,0,0
  x,z = x+math.random(-64,64),z+math.random(-64,64)
  y=256+math.random(-32,32)
  for k,isl in ipairs(cells) do
    if isl and isl.valid then
      table.remove(cells,k)
      local ip = isl.pos
      local ref = minetest.get_player_by_name(name)
      local pos = ip
      players[name] = {pos = pos, valid = false}
      save()
      pos = {x=f(pos.x),y=f(pos.y),z=f(pos.z)}
      ref:set_pos({x=pos.x,y=pos.y+256,z=pos.z})
      return
    end
  end
  local ok = checkpos(x,y,z)
  while not ok do
    x,z = x+math.random(-64,64),z+math.random(-64,64)
    y=256+math.random(-32,32)
    ok = checkpos(x,y,z)
  end
  local ip = {x=x,y=y,z=z}
  spawn_island(name,ip)
  local pl = {
    pos = ip,
    valid = false
  }
  players[name] = pl
  save()
end
local updrate = 0.5
local to_upd = updrate
minetest.register_globalstep(function(dt)
  for f,_ in pairs(queue) do
    local ok,err = coroutine.resume(f)
    if not ok then
      print(err)
      queue[f]=nil
    end
  end
  to_upd = to_upd-dt
  if to_upd <= 0 then
    to_upd = to_upd+updrate
    for k,ref in pairs(minetest.get_connected_players()) do
      local is = get_standing_island(ref:get_player_name())
      if is and is.t == cells and not minetest.check_player_privs(ref,{server = true}) then
        cells[is.k].valid = false
      end
      local p = ref:get_pos()
      if p.y < -64 then
        ref:set_hp(ref:get_hp()-2,{reason="set_hp"})
        if p.y < -128 then
          local land = players[ref:get_player_name()]
          local pos
          if land then
            pos = land.pos
          elseif minetest.check_player_privs(ref,{interact = true}) then
            gen_island_pos(ref:get_player_name())
          end
          if pos then
            pos.y=pos.y+256
            ref:set_pos(pos)
          end
        end
      end
    end
  end
end)

minetest.register_chatcommand("register", {
  description = S"Register island",
  privs = {server = true},
  func = function(name,param)
    if get_standing_island(name) then
      minetest.chat_send_player(name,S"There is an island already")
      return
    end
    local ref = minetest.get_player_by_name(name)
    local pos = ref:get_pos()
    ip = {x=f(pos.x+.5),y=f(pos.y+.5),z=f(pos.z+.5)}
    table.insert(cells,{pos=ip, valid=false})
    minetest.chat_send_player(name,"OK")
    save()
  end
})

minetest.register_chatcommand("unregister", {
  description = S"Unregister island",
  privs = {server = true},
  func = function(name,param)
    local is = get_standing_island(name)
    if not is then
      minetest.chat_send_player(name,S"No island here")
      return
    end
    if is.t == cells then
      cells[is.k] = nil
    end
    if is.t == players then
      local nam = is.owner
      players[nam] = nil
    end
    minetest.chat_send_player(name,S"OK")
    save()
  end
})

minetest.register_chatcommand("assign", {
  description = S"Reassign this island",
  privs = {server = true},
  func = function(name,param)
    local is = get_standing_island(name)
    if not minetest.get_player_by_name(param) then
      minetest.chat_send_player(name,S("No player @1",param))
      return
    end
    if players[param] then
      local ois = players[param]
      table.insert(cells,{pos=ois.pos,valid = false})
      players[param] = nil
    end
    if not is then
      minetest.chat_send_player(name,S"No island here")
      return
    else
      players[name] = {pos = is.pos, valid = is.valid}
      is.t[is.k] = nil
    end
    minetest.chat_send_player(name,S"OK")
    save()
  end
})

minetest.register_chatcommand("unassign", {
  description = S"Unassign this island",
  privs = {server = true},
  func = function(name,param)
    local is = get_standing_island(name)
    if not is then
      minetest.chat_send_player(name,S"No island here")
      return
    end
    if is.t == cells then
      minetest.chat_send_player(name,S"Island is already unassigned")
      return
    end
    if is.t == players then
      local nam = is.owner
      players[nam] = nil
      table.insert(cells,{pos=is.pos,valid=is.valid})
    end
    minetest.chat_send_player(name,S"OK")
    save()
  end
})

minetest.register_chatcommand("validate", {
  description = S"Make this island avaible for newcomers, if not owned by a player",
  privs = {server = true},
  func = function(name,param)
    local is = get_standing_island(name)
    if is then
      is.t[is.k].valid = true
      minetest.chat_send_player(name,S"OK")
    else
      minetest.chat_send_player(name,S"No island here")
      return
    end
    save()
  end
})

minetest.register_chatcommand("invalidate", {
  description = S"Make this island unavaible for newcomers",
  privs = {server = true},
  func = function(name,param)
    local is = get_standing_island(name)
    if is then
      is.t[is.k].valid = false
      minetest.chat_send_player(name,S"OK")
    else
      minetest.chat_send_player(name,S"No island here")
      return
    end
    save()
  end
})

minetest.register_chatcommand("query", {
  description = S"Query information about this island",
  func = function(name,param)
    local is = get_standing_island(name)
    if is then
      minetest.chat_send_player(name,"[")
      minetest.chat_send_player(name,"  owner: "..((is.owner == "" and "(none)" or is.owner) or "(none)"))
      minetest.chat_send_player(name,"  takeable: "..tostring(is.valid))
      minetest.chat_send_player(name,"  pos: "..minetest.pos_to_string(is.pos))
      minetest.chat_send_player(name,"]")
    else
      minetest.chat_send_player(name,S"No island here")
    end
    save()
  end
})

minetest.register_chatcommand("reset",{
  description = S"Get a new island",
  privs = {interact = true},
  func = function(name)
    local utime = minetest.get_server_uptime()
    local cd = cooldowns[name]
    if cd and cd > utime then
      minetest.chat_send_player(name,S("You can't get a new island yet. Wait @1 secs.",(cd-utime)))
      return
    end
    cooldowns[name] = utime + cooldown
    local pl = players[name]
    if pl then
      players[name] = nil
    end
    gen_island_pos(name)
  end
})

minetest.register_on_joinplayer(function(ref)
  local meta = ref:get_meta()
  local name = ref:get_player_name()
  if meta:get_string("islandpos") ~= "" then
    if not players[name] then
      local pos = minetest.string_to_pos(meta:get_string("islandpos"))
      local hascell = false
      for k,v in pairs(players) do
        if vector.length(vector.subtract(v.pos,pos)) < 8 then
          hascell = true
          break
        end
      end
      while true do
        local rem = false
        for k,v in pairs(cells) do
          if vector.length(vector.subtract(v.pos,pos)) < 8 then
            table.remove(cells,k)
            rem = true
            break
          end
        end
        if not rem then
          break
        end
      end
      if not hascell then
        local pl = {
          pos = pos,
          valid = false
        }
        players[name] = pl
      else
        gen_island_pos(name)
      end
    end
    save()
    meta:set_string("island","")
    meta:set_string("islandpos","")
    meta:set_string("islandrange","")
  else
    if not players[name] then
      gen_island_pos(name)
      save()
    else
      local p = players[name]
      if p.islandpos then
        players[name] = {pos = p.islandpos, valid = false}
        save()
      end
      local pos = players[name].pos
      local hascell = false
      for k,v in pairs(players) do
        if vector.length(vector.subtract(v.pos,pos)) < 8 and k ~= name then
          hascell = true
          break
        end
      end
      while true do
        local rem = false
        for k,v in pairs(cells) do
          if vector.length(vector.subtract(v.pos,pos)) < 8 then
            table.remove(cells,k)
            rem = true
            break
          end
        end
        if not rem then
          break
        end
      end
      if hascell then
        players[name] = nil
        gen_island_pos(name)
      end
    end
  end
end)