Target = class()

local teamFilters = {
  all = function() return true end,
  enemy = function(a, b) return a.team ~= b.team end,
  ally = function(a, b) return a.team == b.team end
}

local getEntries = {
  shrine = function(source, teamFilter, t)
    ctx.shrines:each(function(shrine)
      if source ~= shrine and not shrine.untargetable and teamFilter(source, shrine) then
        table.insert(t, {shrine, math.abs(shrine.x - source.x)})
      end
    end)
  end,
  player = function(source, teamFilter, t)
    ctx.players:each(function(player)
      if source ~= player and not player.untargetable and not player.dead and player.invincible == 0 and teamFilter(source, player) then
        table.insert(t, {player, math.abs(player.x - source.x)})
      end
    end)
  end,
  unit = function(source, teamFilter, t)
    ctx.units:each(function(unit)
      if source ~= unit and not unit.untargetable and not unit.dying and teamFilter(source, unit) then
        table.insert(t, {unit, math.abs(unit.x - source.x)})
      end
    end)
  end
}

local function halp(source, teamFilter, arg)
  local targets = {}
  teamFilter = teamFilters[teamFilter]
  table.each(arg, function(kind) getEntries[kind](source, teamFilter, targets) end)
  return targets
end

function Target:closest(source, teamFilter, ...)
  local targets = halp(source, teamFilter, {...})
  table.sort(targets, function(a, b) return a[2] < b[2] end)
  if targets[1] then return unpack(targets[1]) end
  return nil
end

function Target:inRange(source, range, teamFilter, ...)
  local targets = halp(source, teamFilter, {...})

  local i = 1
  while i <= #targets do
    if targets[i][2] > range + targets[i][1].width / 2 then table.remove(targets, i)
    else i = i + 1 end
  end

  table.sort(targets, function(a, b) return a[2] < b[2] end)

  return table.map(targets, function(t) return t[1] end)
end

function Target:location(source, range)
  local ground = ctx.map.height - ctx.map.groundHeight
  local mx = ctx.view:worldPoint(love.mouse.getX())
  local x = math.clamp(mx, source.x - range, source.x + range)
  return x, ground
end

function Target:atMouse(...)
  local mx, my = ctx.view:worldPoint(love.mouse.getPosition())
  for _, entry in ipairs(self:inRange(...)) do
    if entry:contains(mx, my) then return entry end
  end
  return nil
end