--
-- Single village generation
--

village.villages = {}

-- Savefile

local village_file = minetest.get_worldpath() .. "/villages.dat"

local modpath = minetest.get_modpath("village")
local mapseed = minetest.get_mapgen_setting("seed")
local water_level = tonumber(minetest.get_mapgen_setting("water_level"))

--[[ List of village wood materials (schematic replacements)
One of these will be chosen at random and it applies
for the whole world. ]]
local village_replaces = {
   -- Default (Birch + Oak, as specified in schematics)
   {
   },
   -- Birch → Normal (Normal + Oak)
   {
      ["default:planks_birch"] = "default:planks",
      ["default:tree_birch"] = "default:tree",
      ["default:fence_birch"] = "default:fence",
   },
   -- Oak → Normal (Normal + Birch)
   {
      ["default:planks_oak"] = "default:planks",
      ["default:tree_oak"] = "default:tree",
      ["default:fence_oak"] = "default:fence",
   },
   -- Normal wood only
   {
      ["default:planks_birch"] = "default:planks",
      ["default:planks_oak"] = "default:planks",
      ["default:tree_birch"] = "default:tree",
      ["default:tree_oak"] = "default:tree",
      ["default:fence_birch"] = "default:fence",
      ["default:fence_oak"] = "default:fence",
   },
   -- Birch wood only
   {
      ["default:planks"] = "default:planks_birch",
      ["default:planks_oak"] = "default:planks_birch",
      ["default:tree"] = "default:tree_birch",
      ["default:tree_oak"] = "default:tree_birch",
      ["default:fence"] = "default:fence_birch",
      ["default:fence_oak"] = "default:fence_birch",
   },
   -- Oak wood only
   {
      ["default:planks"] = "default:planks_oak",
      ["default:planks_birch"] = "default:planks_oak",
      ["default:tree"] = "default:tree_oak",
      ["default:tree_birch"] = "default:tree_oak",
      ["default:fence"] = "default:fence_oak",
      ["default:fence_birch"] = "default:fence_oak"
   },
}

local village_replace_id

function village.get_id(name, pos)
   return name .. minetest.hash_node_position(pos)
end

function village.save_villages()
   local f = io.open(village_file, "w")

   for name, def in pairs(village.villages) do
      f:write(name .. " " .. def.name .. " "
                 .. minetest.hash_node_position(def.pos) .. "\n")
   end

   io.close(f)
end

function village.load_villages()
   local f = io.open(village_file, "r")

   if f then
      repeat
	 local l = f:read("*l")
	 if l == nil then break end

	 for name, fname, pos in string.gmatch(l, "(.+) (%a+) (%d.+)") do
	    village.villages[name] = {
	       name = fname,
	       pos = minetest.get_position_from_hash(pos),
	    }
	 end
      until f:read(0) == nil

      io.close(f)
   else
      village.save_villages()
   end

   village.load_waypoints()
end

function village.load_waypoints()
   for name, def in pairs(village.villages) do
      nav.remove_waypoint("village_" .. name)
      nav.add_waypoint(
	 def.pos,
	 "village_" .. name,
	 def.name .. " village",
	 true,
	 "village"
      )
   end
end

function village.get_nearest_village(pos)
   local nearest = 100000 -- big number
   local name = nil

   for name, def in pairs(village.villages) do
      local dist = vector.distance(pos, def.pos)
      if dist < nearest then
	 nearest = dist
	 name = name
      end
   end

   return {dist = nearest, name = name}
end

village.chunkdefs = {}

village.chunkdefs["livestock_pen"] = {
   entities = {
      ["mobs:sheep"] = 3,
      ["mobs:boar"] = 1,
   },
}
village.chunkdefs["lamppost"] = { -- not road because of road height limit of 1 nodes
   entity_chance = 2,
   entities = {
      ["mobs:npc_butcher"] = 1,
   },
}
village.chunkdefs["well"] = {
   entities = {
      ["mobs:npc_farmer"] = 1,
      ["mobs:npc_tavernkeeper"] = 1,
   },
}
village.chunkdefs["house"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_farmer"] = 1,
   },
}
village.chunkdefs["tavern"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_tavernkeeper"] = 1,
   },
}

village.chunkdefs["forge"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_blacksmith"] = 1,
   },
}
village.chunkdefs["orchard"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_farmer"] = 1,
   },
}
village.chunkdefs["farm"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_farmer"] = 1,
   },
}
village.chunkdefs["farm_wheat"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_farmer"] = 1,
   },
}
village.chunkdefs["farm_cotton"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_farmer"] = 1,
   },
}
village.chunkdefs["farm_papyrus"] = {
   entity_chance = 2,
   entities = {
      ["mobs:npc_farmer"] = 1,
   },
}

-- List of chunk types. Chunk types are structurs and buildings
-- that are not the well and are placed next to roads.
-- The number is their absolute frequency. The higher the number,
-- the more likely it will occur.
-- The well is not listed here because it acts as the start point.
village.chunktypes = {
   -- chunktype, absolute frequency
   { "house", 12 },
   { "tavern", 6 },
   { "forge", 6 },
   { "farm_wheat", 2 },
   { "farm_cotton", 2 },
   { "farm", 2 },
   { "farm_papyrus", 3 },
   { "livestock_pen", 3 },
   { "orchard", 3 },
}

-- Calculate cumulated absolute frequency and put it in index 3
local chunksum = 0
for i=1, #village.chunktypes do
   chunksum = chunksum + village.chunktypes[i][2]
   village.chunktypes[i][3] = chunksum
end

-- Select a random chunk. The probability of a chunk being selected is
-- <absolute frequency> / <sum of all absolute frequencies>
local function random_chunktype(pr)
   local rnd = pr:next(1, chunksum)
   for i=1, #village.chunktypes do
      if rnd <= village.chunktypes[i][3] then
         return village.chunktypes[i][1]
      end
   end
   return village.chunktypes[#village.chunktypes][1]
end

function village.lift_ground(pos, scanheight)
   -- assume ground is lower than pos.y

   local topnode = nil
   local topdepth = 0

   local fillernode = nil
   local fillerdepth = 0

   local stonenode = nil

   if minetest.get_node({x=pos.x,y=pos.y+1,z=pos.z}).name == "air" then
       return
   end

   for y = pos.y, pos.y - scanheight, -1 do
      local p = {x = pos.x, y = y, z = pos.z}

      local nn = minetest.get_node(p).name
      local an = minetest.get_node({x = p.x, y = p.y + 1, z = p.z}).name

      if nn ~= "air" and minetest.registered_nodes[nn].liquidtype ~= "none" then
	 local nd = minetest.registered_nodes[nn]
	 if not nd.buildable_to then
	    if topnode == nil and nn ~= an then
	       topnode = nn
	    elseif fillernode == nil and nn ~= an then
	       fillernode = nn
	    else
	       stonenode = nn
	    end
	 end

	 if fillernode and not stonenode then
	    fillerdepth = fillerdepth + 1
	 elseif topnode and not fillernode then
	    topdepth = topdepth + 1
	 end
      end
   end

   if topnode == nil then
      topnode = "default:dirt_with_grass"
      topdepth = 1
   end
   if fillernode == nil then
      fillernode = "default:dirt"
      fillerdepth = 3
   end
   if stonenode == nil then
      stonenode = fillernode
   end

   for y = pos.y - scanheight, pos.y do
      local p = {x = pos.x, y = y, z = pos.z}

      local th = pos.y - y

      -- TODO: Optimize speed
      if th <= fillerdepth - topdepth then
	 minetest.set_node(p, {name = fillernode})
      elseif th <= topdepth then
	 minetest.set_node(p, {name = topnode})
      else
	 minetest.set_node(p, {name = stonenode})
      end
   end
end

local function check_empty(pos)
   local min = { x = pos.x, y = pos.y + 1, z = pos.z }
   local max = { x = pos.x+12, y = pos.y+12, z = pos.z+12 }
   local stones = minetest.find_nodes_in_area(min, max, "group:stone")
   local leaves = minetest.find_nodes_in_area(min, max, "group:leaves")
   local trees = minetest.find_nodes_in_area(min, max, "group:tree")
   return #stones <= 15 and #leaves <= 2 and #trees == 0
end

function village.spawn_chunk(pos, orient, replace, pr, chunktype, nofill, dont_check_empty)
   if not dont_check_empty and not check_empty(pos) then
      minetest.log("verbose", "[village] Chunk not generated (too many stone/leaves/trees in the way) at "..minetest.pos_to_string(pos))
      return false
   end

   util.getvoxelmanip(pos, {x = pos.x+12, y = pos.y+12, z = pos.z+12})

   if nofill ~= true then
      minetest.place_schematic(
	 {x = pos.x-6, y = pos.y-5, z = pos.z-6},
	 modpath .. "/schematics/village_filler.mts",
	 "0",
	 {},
	 false
      )

      local py = pos.y-6
      if py < water_level then
          py = water_level
      end
      util.nodefunc(
	 {x = pos.x-6, y = py, z = pos.z-6},
	 {x = pos.x+17, y = py, z = pos.z+17},
	 {"air", "group:liquid"},
	 function(pos)
	    village.lift_ground(pos, 15) -- distance to lift ground; larger numbers will be slower
	 end, true)

      minetest.place_schematic(
	 pos,
	 modpath .. "/schematics/village_empty.mts",
	 "0",
	 {},
	 true
      )

   end

   if chunktype == "orchard" then
      replace["default:tree"] = nil
   end
   minetest.place_schematic(
      pos,
      modpath .. "/schematics/village_" .. chunktype .. ".mts",
      orient,
      replace,
      true
   )

   util.reconstruct(pos, {x = pos.x+12, y = pos.y+12, z = pos.z+12})
   util.fixlight(pos, {x = pos.x+12, y = pos.y+12, z = pos.z+12})

   util.nodefunc(
      pos,
      {x = pos.x+12, y = pos.y+12, z = pos.z+12},
      "default:chest",
      function(pos)
	 goodies.fill(pos, chunktype, pr, "main", 3)
      end, true)

   -- Restrict number of music players
   local music = 0
   util.nodefunc(
      pos,
      {x = pos.x+12, y = pos.y+12, z = pos.z+12},
      "music:player",
      function(pos)
	 if music >= 1 or pr:next(1, 2) > 1 then
	    minetest.remove_node(pos)
	 else
	    music = music + 1
	 end
      end, true)

   -- Replace legacy torches
   -- TODO: Fix the torches in the formspec instead
   util.nodefunc(
      pos,
      {x = pos.x+12, y = pos.y+12, z = pos.z+12},
      "default:torch",
      function(pos)
	 local node = minetest.get_node(pos)
         local dir = minetest.wallmounted_to_dir(node.param2)
         if dir.x ~= 0 or dir.z ~= 0 then
            node.name = "default:torch_wall"
            minetest.set_node(pos, node)
         end
      end, true)



   local chunkdef = village.chunkdefs[chunktype]
   if chunkdef ~= nil then
      if chunkdef.entities ~= nil then
	 if chunkdef.entity_chance ~= nil and pr:next(1, chunkdef.entity_chance) == 1 then
	    util.nodefunc(
	       pos,
	       {x = pos.x+12, y = pos.y+12, z = pos.z+12},
	       "village:entity_spawner",
	       function(pos)
		  minetest.remove_node(pos)
            end)
	    return true
	 end

	 local ent_spawns = {}

	 util.nodefunc(
	    pos,
	    {x = pos.x+12, y = pos.y+12, z = pos.z+12},
	    "village:entity_spawner",
	    function(pos)
	       table.insert(ent_spawns, pos)
	    end, true)

	 if #ent_spawns > 0 then
	    for ent, amt in pairs(chunkdef.entities) do
	       for j = 1, pr:next(1, amt) do
                  if #ent_spawns == 0 then
                     break
                  end
		  local spawn, index = util.choice_element(ent_spawns, pr)
		  if spawn ~= nil then
                     local meta = minetest.get_meta(spawn)
	             meta:set_string("entity", ent)
	             minetest.get_node_timer(spawn):start(1)
                     -- Prevent spawning on same tile
                     table.remove(ent_spawns, index)
		  end
	       end
	    end
	 end
         -- Remove unused entity spawners
         for e=1, #ent_spawns do
             minetest.remove_node(ent_spawns[e])
         end
      end
   end

   if chunktype == "forge" then
      util.nodefunc(
	 pos,
	 {x = pos.x+12, y = pos.y+12, z = pos.z+12},
	 "default:furnace",
	 function(pos)
	    goodies.fill(pos, "FURNACE_SRC", pr, "src", 1)
	    goodies.fill(pos, "FURNACE_DST", pr, "dst", 1)
	    goodies.fill(pos, "FURNACE_FUEL", pr, "fuel", 1)
	 end, true)
   end
   minetest.log("verbose", "[village] Chunk generated at "..minetest.pos_to_string(pos))
   return true
end

function village.spawn_road(pos, houses, built, roads, depth, pr, replace, dont_check_empty)
   if not dont_check_empty and not check_empty(pos) then
      minetest.log("verbose", "[village] Road not generated (too many stone/leaves/trees in the way) at "..minetest.pos_to_string(pos))
      return false
   end

   for i=1,4 do
      local nextpos = {x = pos.x, y = pos.y, z = pos.z}
      local orient = "random"

      if i == 1 then
	 orient = "0"
	 nextpos.z = nextpos.z - 12
      elseif i == 2 then
	 orient = "90"
	 nextpos.x = nextpos.x - 12
      elseif i == 3 then
	 orient = "180"
	 nextpos.z = nextpos.z + 12
      else
	 orient = "270"
	 nextpos.x = nextpos.x + 12
      end

      local hnp = minetest.hash_node_position(nextpos)

      local chunk_ok
      if built[hnp] == nil then
	 built[hnp] = true
	 if depth <= 0 or pr:next(1, 8) < 6 then
	    houses[hnp] = {pos = nextpos, front = pos}

	    local structure = random_chunktype(pr)
	    chunk_ok = village.spawn_chunk(nextpos, orient, replace, pr, structure)
            if not chunk_ok then
               houses[hnp] = false
            end
	 else
	    roads[hnp] = {pos = nextpos}
	    chunk_ok = village.spawn_road(nextpos, houses, built, roads, depth - 1, pr, replace)
            if not chunk_ok then
               roads[hnp] = false
            end
	 end
      end
   end
   return true
end

function village.spawn_village(pos, pr, force_place_well)
   local name = village.name.generate(pr)

   local depth = pr:next(village.min_size, village.max_size)

   village.villages[village.get_id(name, pos)] = {
      name = name,
      pos = pos,
   }

   village.save_villages()
   village.load_waypoints()

   local houses = {}
   local built = {}
   local roads = {}

   local spawnpos = pos

   -- Get village wood type based on mapseed. All villages in the world
   -- will have the same style.
   -- This is done because the schematic replacements cannot be changed
   -- once the schematic was loaded.
   if not village_replace_id then
      local vpr = PseudoRandom(mapseed)
      village_replace_id = vpr:next(1,#village_replaces)
   end
   local replace = village_replaces[village_replace_id]
   local dirt_path = "default:heated_dirt_path"
   local chunk_ok

   -- For measuring the generation time
   local t1 = os.clock()

   -- Every village generation starts with a well.
   chunk_ok = village.spawn_chunk(pos, "0", replace, pr, "well", nil, force_place_well == true)
   if not chunk_ok then
      -- Oops! Not enough space for the well. Village generation fails.
      return false
   end

   local wellpos = table.copy(pos)

   built[minetest.hash_node_position(pos)] = true

   -- Generate a road at the well. The road tries to grow in 4 directions
   -- growing either recursively more roads or buildings (where the road
   -- terminates)
   village.spawn_road(pos, houses, built, roads, depth, pr, replace, true)

   local function connects(pos, nextpos)
      local hnp = minetest.hash_node_position(nextpos)

      if houses[hnp] ~= nil and houses[hnp] ~= false then
	 if vector.equals(houses[hnp].front, pos) then
	    return true
	 end
      end

      if roads[hnp] ~= nil and roads[hnp] ~= false then
	 return true
      end

      if vector.equals(pos, nextpos) or vector.equals(nextpos, spawnpos) then
	 return true
      end
   end

   -- Add position of well to roads list to connect it properly with
   -- the road network.
   local hnp = minetest.hash_node_position(wellpos)
   roads[hnp] = { pos = wellpos, is_well = true }

   -- Connect dirt paths with other village tiles.
   -- The dirt path schematic uses planks and cobble for each of the 4 cardinal
   -- directions and it will be replaced either with a dirt path or
   -- the ground.

   for _,road in pairs(roads) do
   if road ~= false then

      local replaces = {
	 ["default:planks"]       = "default:dirt_with_grass", -- north
	 ["default:cobble"]       = "default:dirt_with_grass", -- east
	 ["default:planks_oak"]   = "default:dirt_with_grass", -- south
	 ["default:planks_birch"] = "default:dirt_with_grass"  -- west
      }

      if not road.is_well then
         village.spawn_chunk(road.pos, "0", replaces, pr, "road")
      end

      local amt_connections = 0

      for i = 1, 4 do
	 local nextpos = {x = road.pos.x, y = road.pos.y, z = road.pos.z}

	 if i == 1 then
	    nextpos.z = nextpos.z + 12
	    if connects(road.pos, nextpos) then
               amt_connections = amt_connections + 1
               local nodes = minetest.find_nodes_in_area(vector.add(road.pos, {x=4, y=0, z=8}), vector.add(road.pos, {x=7,y=0,z=11}), {"default:dirt_with_grass"})
               minetest.bulk_set_node(nodes, {name=dirt_path})
	    end
	 elseif i == 2 then
	    nextpos.x = nextpos.x + 12
	    if connects(road.pos, nextpos) then
               amt_connections = amt_connections + 1
               local nodes = minetest.find_nodes_in_area(vector.add(road.pos, {x=8, y=0, z=4}), vector.add(road.pos, {x=11,y=0,z=7}), {"default:dirt_with_grass"})
               minetest.bulk_set_node(nodes, {name=dirt_path})
	    end
	 elseif i == 3 then
	    nextpos.z = nextpos.z - 12
	    if connects(road.pos, nextpos) then
               amt_connections = amt_connections + 1
               local nodes = minetest.find_nodes_in_area(vector.add(road.pos, {x=4, y=0, z=0}), vector.add(road.pos, {x=7,y=0,z=3}), {"default:dirt_with_grass"})
               minetest.bulk_set_node(nodes, {name=dirt_path})
	    end
	 else
	    nextpos.x = nextpos.x - 12
	    if connects(road.pos, nextpos) then
               amt_connections = amt_connections + 1
               local nodes = minetest.find_nodes_in_area(vector.add(road.pos, {x=0, y=0, z=4}), vector.add(road.pos, {x=3,y=0,z=7}), {"default:dirt_with_grass"})
               minetest.bulk_set_node(nodes, {name=dirt_path})
	    end
	 end

      end

      if amt_connections >= 2 and not road.is_well then
	 village.spawn_chunk(
	    {x = road.pos.x, y = road.pos.y+1, z = road.pos.z},
	    "0",
	    {},
	    pr,
	    "lamppost",
	    true,
	    true
         )
      end
   end
   end
   minetest.log("action", string.format("[village] Took %.2fms to generate village", (os.clock() - t1) * 1000))
   return true
end

minetest.register_on_mods_loaded(village.load_villages)