-- MODULES REQUIRED...

-- input manager module which will be linked to the input handler object
local user_input = require "modules.input_manager.lua"


-- STATE MACHINE BEGINS...

local state_machine = {

  { -- 1
    name = "standing",
    init = function(self)
      print("Entered STANDING state")
      -- play standing animation, etc...
    end,
    update = function(self, dt)
      -- no functionality here beyond changing state according to user input...
      -- jump button begins jumping (with or without directional input)
      if user_input.jump_btn == true then
        set_state(self, "jumping")
      -- input manager sets directional flag to true on left or right input,
      -- which shifts state machine to walking state
      elseif user_input.directional == true then
        set_state(self, "walking")
      end
    end,
    exit = function(self)
      print("Leaving STANDING state")
    end,
  }, -- 1 STANDING

  { -- 2
    name = "walking",
    init = function(self)
      print("Entered WALKING state")
      -- set walking animation, start footsteps sound effect, etc...
    end,
    update = function(self, dt)
      -- handle walking in either direction
      if user_input.left == true then
        -- adjust velocity/position, negative on the x-axis...
      elseif user_input.right == true then
        -- adjust velocity/position, positive on the x-axis...
      elseif user_input.jump_btn == true then
        set_state(self, "jumping") -- jump if btn pressed
      else set_state(self, "standing") -- if no further directional input, switch back to standing state
      end
    end,
    exit = function(self)
      print("Leaving WALKING state")
      -- stop playing footsteps sound effect, etc..
    end,
  }, -- 2 WALKING

  { -- 3
    name = "jumping",
    init = function(self)
      print("Entered JUMPING state")
      -- play jumping animation and start jump sound effect etc...
      state_timer = 0 -- reset state timer to limit maximum jump height
    end,
    update = function(self, dt)
      -- handle horizontal movement in the air...
      if user_input.left == true then
        -- adjust velocity/position, negative on the x-axis...
      elseif user_input.right == true then
        -- adjust velocity/position, positive on the x-axis...
      end
      -- check for collisions and adjust state accordingly... ie. to damaged falling state etc..
      -- increment state_timer to record how long we have been jumping up
      state_timer = state_timer + 1
      -- continue gaining height if not reached max jump frames and jump btn still pressed
      if state_timer <= self.max_jump_frames and user_input.jump_btn == true then
        -- adjust velocity/position, positive on the y-axis..
      else set_state(self, "falling") -- else, switch to falling state
      end
    end,
    exit = function(self)
      print("Leaving JUMPING state")
    end,
  }, -- 3 JUMPING

  { -- 4
    name = "falling",
    init = function(self)
      print("Entered FALLING state")
      -- play falling animation, etc..
    end,
    update = function(self, dt)
      -- handle horizontal movement..
      -- adjust velocity/position negative on the y-axis
      -- check for ground collision..
      if self.is_on_ground == true then
        set_state(self, "landing")
      end
    end,
    exit = function(self)
      print("Leaving FALLING state")
    end,
  }, -- 4 FALLING

  { -- 5
    name = "landing",
    init = function(self)
      print("Entering LANDING state")
      -- play landing animation and sound effect, etc..
      -- reset state_timer
      state_timer = 0
    end,
    update = function(self, dt)
      -- increment state_timer
      state_timer = state_timer + 1
      -- check if landing delay/lag completed, switch to standing state if true
      if state_timer >= self.landing_lag then
        set_state(self, "standing")
      end
    end,
    exit = function(self)
      print("Leaving LANDING state")
      -- play stand up/ready sound effect..
    end,
  }, -- 5 LANDING

--[[ To add more states copy and edit the following...
  { --
    name = "",
    init = function(self)
    end,
    update = function(self, dt)
    end,
    exit = function(self)
    end,
  }, --
]]

} -- state_machine ENDS

-- STATE MACHINE VARIABLES/FUNCTIONS --

local state = 1 -- variable to track the current state
-- state_machine begins in state 1, i.e. standing state

local state_timer = 0 -- variable to track time spent in any given state

function set_state(self, new_state) -- called to change states
  -- run the exit function on the current state
  state_machine[state].exit(self)
  -- determine the new state to set from the "new_state" string passed into this function...
  local state_to_set = 0
  for i, v in ipairs(state_machine) do -- loop through states in state_machine table
    if v.name == new_state then -- if state.name is the requested new state
      state_to_set = i -- record the requested state's index (i)
      break -- stop looping as we have found the next state
    end
  end
  -- adjust the current state variable
    state = state_to_set
  -- call the init() script of the new current state
    state_machine[state].init(self)
end

-- CORE FUNCTIONS

function init(self)
  -- call the init() function of the starting default state
    state_machine[state].init(self,dt)
end

function update(self, dt)
  -- call the update funciton of the current state
    state_machine[state].update(self,dt)
end