-- classes/states :: a finite state machine for objects

--[[
  Copyright © 2022 Kazhnuz

  Permission is hereby granted, free of charge, to any person obtaining a copy of
  this software and associated documentation files (the "Software"), to deal in
  the Software without restriction, including without limitation the rights to
  use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
  the Software, and to permit persons to whom the Software is furnished to do so,
  subject to the following conditions:

  The above copyright notice and this permission notice shall be included in all
  copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
  FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
  COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
  IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
]]

local StateMachine = Object:extend()

function StateMachine.addState(self, name, state, isDefault)
    if (self.states == nil) then
        self.states = {}
        self.states.list = {}
    end

	self.states.list[name] = state
    
    if (isDefault == true) then
    	self.states.default = name
	end
end

function StateMachine.addStates(self, statesPath, default)
    local states = require(statesPath)
    for i, stateName in ipairs(states) do
        local state = require(statesPath .. "." .. stateName)
        self:addState(stateName, state)
    end
    self.states.default = default
end

function StateMachine:initStates()
    if (self.states == nil) then
        self.states = {}
        self.states.list = {}
    end
	self.currentState = self.states.default or "none"
end

function StateMachine:updateState(dt)
    self:playStateFunc("update", dt)
end

function StateMachine:haveState(state)
    return (self.states.list[state] ~= nil)
end

function StateMachine:setState(state)
    if (not self:haveState(state)) then
        return self.currentState
    end
    self:playStateFunc("stop", state)
    local currentState = self.currentState
    self.currentState = state
    self:playStateFunc("start", currentState)
    return state
end

function StateMachine:getState()
	return self.states.list[self.currentState]
end

function StateMachine:getStateVar(varName, default)
	local state = self:getState()
    if (state == nil) then
        return nil
    end
    local var = state[varName]
    if (var == nil) then
        return default
    end
    return var
end

function StateMachine:playStateFunc(funcName, ...)
	local state = self:getState()
    if (state == nil) then
        return
    end
    local func = state[funcName]
    if (func ~= nil) then
        func(self, ...)
    end
end

return StateMachine