-- [Mantis 591] Test to check that monsters don't vacillate between two
-- squares when trying to reach the player but blocked by plants.

local map = "monster_plant_pathfind"
local FAILMAP = map .. ".map"

debug.flush_map_memory()
debug.goto_place("D:2")
dgn.reset_level()
assert(dgn.place_map(dgn.map_by_name(map), true, true),
       "Could not place " .. map)

local stair = test.find_feature('stone_stairs_up_i')
assert(stair, "Could not find stairs up")

you.moveto(stair.x, stair.y)
local you_x, you_y = you.pos()
assert(you_x == stair.x and you_y == stair.y,
       "Could not move player " .. dgn.point(you_x, you_y) ..
         " to stair " .. stair)

local monster = test.find_monsters("hippogriff")[1]

local function monster_pos()
  local p = dgn.point(monster.x, monster.y)
  -- Monster position is relative to the player position:
  p = p + stair
  return p
end

debug.los_changed()

assert(you.see_cell(monster_pos().x, monster_pos().y),
       "Player at " .. stair .. " cannot see monster at "
         .. monster_pos())
assert(you.see_cell(you_x + 1, you_y),
       "Player at " .. stair .. " cannot see cell at "
         .. (stair + dgn.point(1, 0)))


-- Assert if the monster moves back and forth between positions
local function check_monster_moves_repeat(monster, nmoves)
  local visited_points = { }

  local function note_position(p)
    local key = p.y * dgn.GXM + p.x
    local visits = visited_points[key] or 0
    visits = visits + 1
    visited_points[key] = visits
    debug.dump_map(FAILMAP)
    assert(visits < 2,
           "Monster revisited " .. p .. "; dumped map to " .. FAILMAP)
  end

  local oldpos = nil
  for i = 1, nmoves do
    local p = monster_pos()
    crawl.message("Monster " .. monster.name .. " at " .. p)
    if p ~= oldpos then
      note_position(p)
    end
    oldpos = p

    -- Wake up the monster and kick it into seek (hopefully).
    debug.seen_monsters_react()
    -- Draw the view to give the user something to look at.
    debug.viewwindow(true)
    monster.add_energy(10)
    assert(monster.beh == "seek",
           "Monster " .. monster.name .. " is not in seek mode")
    monster.run_ai()
  end
end

check_monster_moves_repeat(monster, 6)