-- Copyright (c) 2021 Maksim Tuprikov <insality@gmail.com>. This code is licensed under MIT license

--- Component to handle swipe gestures on node.
-- Swipe will be triggered, if swipe was started and
-- ended on one node
--
-- <a href="https://insality.github.io/druid/druid/index.html?example=general_swipe" target="_blank"><b>Example Link</b></a>
-- @module Swipe
-- @within BaseComponent
-- @alias druid.swipe

--- Swipe node
--@param node node

--- Restriction zone
--@param click_zone node|nil

--- Trigger on swipe event(self, swipe_side, dist, delta_time)
--@param  event event on_swipe

---

local event = require("event.event")
local const = require("druid.const")
local helper = require("druid.helper")
local component = require("druid.component")

---@class druid.swipe: druid.base_component
---@field node node
---@field on_swipe event function(side, dist, dt), side - "left", "right", "up", "down"
---@field style table
---@field click_zone node
---@field private _trigger_on_move boolean
---@field private _swipe_start_time number
---@field private _start_pos vector3
---@field private _is_enabled boolean
---@field private _is_mobile boolean
local M = component.create("swipe")


local function start_swipe(self, action)
	self._swipe_start_time = socket.gettime()
	self._start_pos.x = action.x
	self._start_pos.y = action.y
end


local function reset_swipe(self, action)
	self._swipe_start_time = 0
end


local function check_swipe(self, action)
	local dx = action.x - self._start_pos.x
	local dy = action.y - self._start_pos.y
	local dist = helper.distance(self._start_pos.x, self._start_pos.y, action.x, action.y)
	local delta_time = socket.gettime() - self._swipe_start_time
	local is_swipe = self.style.SWIPE_THRESHOLD <= dist and delta_time <= self.style.SWIPE_TIME

	if is_swipe then
		local is_x_swipe = math.abs(dx) >= math.abs(dy)
		local swipe_side = "undefined"

		if is_x_swipe and dx > 0 then
			swipe_side = "right"
		end
		if is_x_swipe and dx < 0 then
			swipe_side = "left"
		end
		if not is_x_swipe and dy > 0 then
			swipe_side = "up"
		end
		if not is_x_swipe and dy < 0 then
			swipe_side = "down"
		end

		self.on_swipe:trigger(self:get_context(), swipe_side, dist, delta_time)
		reset_swipe(self)
	end
end


--- Component style params.
-- You can override this component styles params in druid styles table
-- or create your own style
---@class druid.swipe.style
---@field SWIPE_TIME number|nil Maximum time for swipe trigger. Default: 0.4
---@field SWIPE_THRESHOLD number|nil Minimum distance for swipe trigger. Default: 50
---@field SWIPE_TRIGGER_ON_MOVE boolean|nil If true, trigger on swipe moving, not only release action. Default: false

---@param style druid.swipe.style
function M:on_style_change(style)
	self.style = {}
	self.style.SWIPE_TIME = style.SWIPE_TIME or 0.4
	self.style.SWIPE_THRESHOLD = style.SWIPE_THRESHOLD or 50
	self.style.SWIPE_TRIGGER_ON_MOVE = style.SWIPE_TRIGGER_ON_MOVE or false
end


---Swipe constructor
---@param node_or_node_id node|string
---@param on_swipe_callback function
function M:init(node_or_node_id, on_swipe_callback)
	self._trigger_on_move = self.style.SWIPE_TRIGGER_ON_MOVE
	self.node = self:get_node(node_or_node_id)

	self._swipe_start_time = 0
	self._start_pos = vmath.vector3(0)

	self.click_zone = nil
	self.on_swipe = event.create(on_swipe_callback)
end


function M:on_late_init()
	if not self.click_zone then
		local stencil_node = helper.get_closest_stencil_node(self.node)
		if stencil_node then
			self:set_click_zone(stencil_node)
		end
	end
end


---@param action_id hash
---@param action action
function M:on_input(action_id, action)
	if action_id ~= const.ACTION_TOUCH then
		return false
	end

	if not gui.is_enabled(self.node, true) then
		return false
	end

	local is_pick = helper.pick_node(self.node, action.x, action.y, self.click_zone)
	if not is_pick then
		reset_swipe(self, action)
		return false
	end

	if self._swipe_start_time ~= 0 and (self._trigger_on_move or action.released) then
		check_swipe(self, action)
	end

	if action.pressed then
		start_swipe(self, action)
	end

	if action.released then
		reset_swipe(self, action)
	end

	return true
end


function M:on_input_interrupt()
	reset_swipe(self)
end


--- Strict swipe click area. Useful for
-- restrict events outside stencil node
---@param zone node|string|nil Gui node
function M:set_click_zone(zone)
	if not zone then
		self.click_zone = nil
		return
	end

	self.click_zone = self:get_node(zone)
end


return M