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

--- Druid component to handle the progress bars.
-- <b># Overview #</b>
--
-- <b># Notes #</b>
--
-- • Progress Node should be fully filled in your GUI scene node. It will be the progress maximum size
--
-- • Progress correct working with Slice9 nodes, it trying to set size by _set_size_ first, if it is not possible, it set up sizing via _set_scale_
--
-- • Progress bar can fill only by vertical or horizontal size. If you want make diagonal progress bar, just rotate node in GUI scene
--
-- • If you have glitchy or dark texture bug with progress bar, try to disable mipmaps in your texture profiles
--
--
-- <a href="https://insality.github.io/druid/druid/index.html?example=general_progress_bar" target="_blank"><b>Example Link</b></a>
-- @module Progress
-- @within BaseComponent
-- @alias druid.progress

--- On progress bar change callback(self, new_value)
-- @tfield druid.event on_change druid.event

--- Progress bar fill node
-- @tfield node node

--- The progress bar direction.
--
-- The values are: "x" or "y". (const.SIDE.X or const.SIDE.Y)
-- @tfield string key

--- Current progress bar scale
-- @tfield vector3 scale

--- Current progress bar size
-- @tfield vector3 size

--- Maximum size of progress bar
-- @tfield number max_size

--- Progress bar slice9 settings
-- @tfield vector4 slice

---

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

---@class druid.progress: druid.base_component
---@field node node
---@field on_change druid.event
---@field style table
---@field key string
---@field prop hash
local M = component.create("progress")


local function check_steps(self, from, to, exactly)
	if not self.steps then
		return
	end

	for i = 1, #self.steps do
		local step = self.steps[i]
		local v1, v2 = from, to
		if v1 > v2 then
			v1, v2 = v2, v1
		end

		if v1 < step and step < v2 then
			self.step_callback(self:get_context(), step)
		end
		if exactly and exactly == step then
			self.step_callback(self:get_context(), step)
		end
	end
end


local function set_bar_to(self, set_to, is_silent)
	local prev_value = self.last_value
	local other_side = self.key == const.SIDE.X and const.SIDE.Y or const.SIDE.X
	self.last_value = set_to

	local total_width = set_to * self.max_size[self.key]

	local scale = 1
	if self.slice_size[self.key] > 0 then
		scale = math.min(total_width / self.slice_size[self.key], 1)
	end
	local size = math.max(total_width, self.slice_size[self.key])

	do -- Scale other side
		-- Decrease other side of progress bar to match the oppotize slice_size
		local minimal_size = self.size[other_side] - self.slice_size[other_side]
		local maximum_size = self.size[other_side]
		local scale_diff = (maximum_size - minimal_size) / maximum_size
		local other_scale = 1 - (scale_diff * (1 - scale))
		self.scale[other_side] = other_scale
	end

	self.scale[self.key] = scale
	gui.set_scale(self.node, self.scale)

	self.size[self.key] = size
	gui.set_size(self.node, self.size)

	if not is_silent then
		check_steps(self, prev_value, set_to)
		if prev_value ~= self.last_value then
			self.on_change:trigger(self:get_context(), self.last_value)
		end
	end
end


--- Component style params.
-- You can override this component styles params in druid styles table
-- or create your own style
-- @table style
-- @tfield number|nil SPEED Progress bas fill rate. More -> faster. Default: 5
-- @tfield number|nil MIN_DELTA Minimum step to fill progress bar. Default: 0.005
function M:on_style_change(style)
	self.style = {}
	self.style.SPEED = style.SPEED or 5
	self.style.MIN_DELTA = style.MIN_DELTA or 0.005
end


--- The Progress constructor
---@param self Progress Progress
---@param node string|node Node name or GUI Node itself.
---@param key string Progress bar direction: const.SIDE.X or const.SIDE.Y
---@param init_value number|nil Initial value of progress bar. Default: 1
function M:init(node, key, init_value)
	assert(key == const.SIDE.X or const.SIDE.Y, "Progress bar key should be 'x' or 'y'")

	self.key = key
	self.prop = hash("scale." .. self.key)

	self._init_value = init_value or 1
	self.node = self:get_node(node)
	self.scale = gui.get_scale(self.node)
	self.size = gui.get_size(self.node)
	self.max_size = gui.get_size(self.node)
	self.slice = gui.get_slice9(self.node)
	self.last_value = self._init_value

	self.slice_size = vmath.vector3(
		self.slice.x + self.slice.z,
		self.slice.y + self.slice.w,
		0
	)

	self.on_change = Event()

	self:set_to(self.last_value)
end


function M:on_layout_change()
	self:set_to(self.last_value)
end


function M:on_remove()
	-- Return default size
	gui.set_size(self.node, self.max_size)
end


function M:update(dt)
	if self.target then
		local prev_value = self.last_value
		local step = math.abs(self.last_value - self.target) * (self.style.SPEED*dt)
		step = math.max(step, self.style.MIN_DELTA)
		self:set_to(helper.step(self.last_value, self.target, step))

		if self.last_value == self.target then
			check_steps(self, prev_value, self.target, self.target)

			if self.target_callback then
				self.target_callback(self:get_context(), self.target)
			end

			self.target = nil
		end
	end
end


--- Fill a progress bar and stop progress animation
---@param self Progress Progress
function M:fill()
	set_bar_to(self, 1, true)
end


--- Empty a progress bar
---@param self Progress Progress
function M:empty()
	set_bar_to(self, 0, true)
end


--- Instant fill progress bar to value
---@param self Progress Progress
---@param to number Progress bar value, from 0 to 1
function M:set_to(to)
	to = helper.clamp(to, 0, 1)
	set_bar_to(self, to)
end


--- Return current progress bar value
---@param self Progress Progress
function M:get()
	return self.last_value
end


--- Set points on progress bar to fire the callback
---@param self Progress Progress
---@param steps number[] Array of progress bar values
---@param callback function Callback on intersect step value
-- @usage progress:set_steps({0, 0.3, 0.6, 1}, function(self, step) end)
function M:set_steps(steps, callback)
	self.steps = steps
	self.step_callback = callback
end


--- Start animation of a progress bar
---@param self Progress Progress
---@param to number value between 0..1
---@param callback function|nil Callback on animation ends
function M:to(to, callback)
	to = helper.clamp(to, 0, 1)
	-- cause of float error
	local value = helper.round(to, 5)
	if value ~= self.last_value then
		self.target = value
		self.target_callback = callback
	else
		if callback then
			callback(self:get_context(), to)
		end
	end
end


--- Set progress bar max node size
---@param self Progress Progress
---@param max_size vector3 The new node maximum (full) size
---@return Progress Progress
function M:set_max_size(max_size)
	self.max_size[self.key] = max_size[self.key]
	self:set_to(self.last_value)
	return self
end


return M