list.lua

local List = {
	start_callback = nil
}

local function inside(mx, my, x, y, w, h)
	return mx >= x and mx <= (x+w) and my >= y and my <= (y+h)
end

function List:new()
	o = {}
	setmetatable(o, self)
	self.__index = self

	o.items = {}
	o.files = {}

	o.x = 50
	o.y = 70

	o.width = 400
	o.height = 500

	o.item_height = 23
	o.sum_item_height = 0

	o.bar_size = 20
	o.bar_pos = 0
	o.bar_max_pos = 0
	o.bar_width = 15
	o.bar_lock = nil

	return o
end

function List:add(item, file)
	table.insert(self.items, item)
	table.insert(self.files, file)
end

function List:done()
	self.items.n = #self.items

	-- Recalc bar size.
	self.bar_pos = 0

	local num_items = (self.height/self.item_height)
	local ratio = num_items/self.items.n
	self.bar_size = self.height * ratio
	self.bar_max_pos = self.height - self.bar_size - 3

	-- Calculate height of everything.
	self.sum_item_height = (self.item_height+1) * self.items.n + 2
end

function List:hasBar()
	return self.sum_item_height > self.height
end

function List:getBarRatio()
	return self.bar_pos/self.bar_max_pos
end

function List:getOffset()
	local ratio = self.bar_pos/self.bar_max_pos
	return math.floor((self.sum_item_height-self.height)*ratio + 0.5)
end

function List:update(dt)
	if self.bar_lock then
		local dy = math.floor(love.mouse.getY()-self.bar_lock.y+0.5)
		self.bar_pos = self.bar_pos + dy

		if self.bar_pos < 0 then
			self.bar_pos = 0
		elseif self.bar_pos > self.bar_max_pos then
			self.bar_pos = self.bar_max_pos
		end

		self.bar_lock.y = love.mouse.getY()
	end
end

function List:mousepressed(mx, my, b)
	if self:hasBar() then
		if b == "l" then
			local x, y, w, h = self:getBarRect()
			if inside(mx, my, x, y, w, h) then
				self.bar_lock = { x = mx, y = my }
			end
		end

		local per_pixel = (self.sum_item_height-self.height)/self.bar_max_pos
		local bar_pixel_dt = math.floor(((self.item_height)*3)/per_pixel + 0.5)

		if b == "wd" then
			self.bar_pos = self.bar_pos + bar_pixel_dt
			if self.bar_pos > self.bar_max_pos then 
				self.bar_pos = self.bar_max_pos 
			end
		elseif b == "wu" then
			self.bar_pos = self.bar_pos - bar_pixel_dt
			if self.bar_pos < 0 then 
				self.bar_pos = 0 
			end
		end
	end

	if b == "l" and inside(mx, my, self.x+2, self.y+1, self.width-3, self.height-3) then
		local tx, ty = mx-self.x, my + self:getOffset() - self.y
		local index = math.floor((ty/self.sum_item_height)*self.items.n)
		local i = self.items[index+1]
		local f = self.files[index+1]
		if f then
			self.start_callback(i, f)
		end
	end
end

function List:mousereleased(x, y, b)
	if self:hasBar() then
		if b == "l" then
			self.bar_lock = nil
		end
	end
end

function List:getBarRect()
	return self.x+self.width+2, self.y+1+self.bar_pos,
	self.bar_width-3, self.bar_size
end

function List:getItemRect(i)
	return self.x+2, self.y+((self.item_height+1)*(i-1)+1)-self:getOffset(),
	self.width-3, self.item_height
end

function List:draw()
	love.graphics.setLineWidth(2)
	love.graphics.setLineStyle("rough")
	love.graphics.setFont(self.font)

	love.graphics.setColor(48, 156, 225)

	local mx, my = love.mouse.getPosition()

	-- Get interval to display.
	local start_i = math.floor( self:getOffset()/(self.item_height+1) ) + 1
	local end_i = start_i+math.floor( self.height/(self.item_height+1) ) + 1

	if end_i > self.items.n then 
		end_i = self.items.n 
	end

	love.graphics.setScissor(self.x, self.y, self.width, self.height)

	-- Items.
	for i = start_i,end_i do
		local x, y, w, h = self:getItemRect(i)
		local hover = inside(mx, my, x, y, w, h)

		if hover then
			love.graphics.setColor(0, 0, 0, 127)
		else
			love.graphics.setColor(0, 0, 0, 63)
		end

		love.graphics.rectangle("fill", x+1, y+i+1, w-3, h)

		if hover then
			love.graphics.setColor(255, 255, 255)
		else
			love.graphics.setColor(255, 255, 255, 127)
		end

		local e_id = string.sub(self.items[i], 1, 5)
		local e_rest = string.sub(self.items[i], 5)

		love.graphics.print(e_id, x+10, y+i+6)  --Updated y placement -- Used to change position of Example IDs
		love.graphics.print(e_rest, x+50, y+i+6) --Updated y placement -- Used to change position of Example Titles
	end

	love.graphics.setScissor()

	-- Bar.
	if self:hasBar() then
		local x, y, w, h = self:getBarRect()
		local hover = inside(mx, my, x, y, w, h)

		if hover or self.bar_lock then
			love.graphics.setColor(0, 0, 0, 127)
		else
			love.graphics.setColor(0, 0, 0, 63)
		end
		love.graphics.rectangle("fill", x, y, w, h)
	end

	-- Border.
	love.graphics.setColor(0, 0, 0, 63)
	love.graphics.rectangle("line", self.x+self.width, self.y, self.bar_width, self.height)
	love.graphics.rectangle("line", self.x, self.y, self.width, self.height)
end

return List