local options = require("mp.options")

local opts = {
	blur_radius = 10,
	blur_power = 10,
	minimum_black_bar_size = 3,
	mode = "all",
	active = true,
	reapply_delay = 0.5,
	watch_later_fix = false,
	only_fullscreen = true,
}
options.read_options(opts)

local active = opts.active
local applied = false

function set_lavfi_complex(filter)
	if not filter and mp.get_property("lavfi-complex") == "" then
		return
	end
	local force_window = mp.get_property("force-window")
	local sub = mp.get_property("sub")
	mp.set_property("force-window", "yes")
	if not filter then
		mp.set_property("lavfi-complex", "")
		mp.set_property("vid", "1")
	else
		if not opts.watch_later_fix then
			mp.set_property("vid", "no")
		end
		mp.set_property("lavfi-complex", filter)
	end
	mp.set_property("sub", "no")
	mp.set_property("force-window", force_window)
	mp.set_property("sub", sub)
end

function set_blur()
	if applied then
		return
	end
	if not mp.get_property("video-out-params") then
		return
	end
	if opts.only_fullscreen and not mp.get_property_bool("fullscreen") then
		return
	end
	local video_aspect = mp.get_property_number("video-aspect-override")
	local ww, wh = mp.get_osd_size()

	if math.abs(ww / wh - video_aspect) < 0.05 then
		return
	end
	if opts.mode == "horizontal" and ww / wh < video_aspect then
		return
	end
	if opts.mode == "vertical" and ww / wh > video_aspect then
		return
	end

	local par = mp.get_property_number("video-params/par")
	local height = mp.get_property_number("video-params/h")
	local width = mp.get_property_number("video-params/w")

	local split = "[vid1] split=3 [a] [v] [b]"
	local crop_format = "crop=%s:%s:%s:%s"
	local scale_format = "scale=width=%s:height=%s:flags=neighbor"

	local stack_direction, cropped_scaled_1, cropped_scaled_2, blur_size

	if ww / wh > video_aspect then
		blur_size = math.floor((ww / wh) * height / par - width)
		local nudge = blur_size % 2
		blur_size = blur_size / 2

		local height_with_maximized_width = height / width * ww
		local visible_height = math.floor(height * par * wh / height_with_maximized_width)
		local visible_width = math.floor(blur_size * wh / height_with_maximized_width)

		local cropped_1 = string.format(crop_format, visible_width, visible_height, "0", (height - visible_height) / 2)
		local scaled_1 = string.format(scale_format, blur_size + nudge, height)
		cropped_scaled_1 = cropped_1 .. "," .. scaled_1

		local cropped_2 = string.format(
			crop_format,
			visible_width,
			visible_height,
			width - visible_width,
			(height - visible_height) / 2
		)
		local scaled_2 = string.format(scale_format, blur_size, height)
		cropped_scaled_2 = cropped_2 .. "," .. scaled_2
		stack_direction = "h"
	else
		blur_size = math.floor((wh / ww) * width * par - height)
		local nudge = blur_size % 2
		blur_size = blur_size / 2

		local width_with_maximized_height = width / height * wh
		local visible_width = math.floor(width * ww / width_with_maximized_height)
		local visible_height = math.floor(blur_size * ww / width_with_maximized_height)

		local cropped_1 = string.format(crop_format, visible_width, visible_height, (width - visible_width) / 2, "0")
		local scaled_1 = string.format(scale_format, width, blur_size + nudge)
		cropped_scaled_1 = cropped_1 .. "," .. scaled_1

		local cropped_2 = string.format(
			crop_format,
			visible_width,
			visible_height,
			(width - visible_width) / 2,
			height - visible_height
		)
		local scaled_2 = string.format(scale_format, width, blur_size)
		cropped_scaled_2 = cropped_2 .. "," .. scaled_2
		stack_direction = "v"
	end

	if blur_size < math.max(1, opts.minimum_black_bar_size) then
		return
	end
	local lr = math.min(opts.blur_radius, math.floor(blur_size / 2) - 1)
	local cr = math.min(opts.blur_radius, math.floor(blur_size / 4) - 1)
	local blur = string.format("boxblur=lr=%i:lp=%i:cr=%i:cp=%i", lr, opts.blur_power, cr, opts.blur_power)

	zone_1 = string.format("[a] %s,%s [a_fin]", cropped_scaled_1, blur)
	zone_2 = string.format("[b] %s,%s [b_fin]", cropped_scaled_2, blur)

	local par_fix = "setsar=ratio=" .. tostring(par) .. ":max=10000"

	stack = string.format("[a_fin] [v] [b_fin] %sstack=3,%s [vo]", stack_direction, par_fix)
	filter = string.format("%s;%s;%s;%s", split, zone_1, zone_2, stack)
	set_lavfi_complex(filter)
	applied = true
end

function unset_blur()
	set_lavfi_complex()
	applied = false
end

local reapplication_timer = mp.add_timeout(opts.reapply_delay, set_blur)
reapplication_timer:kill()

function reset_blur(k, v)
	unset_blur()
	reapplication_timer:kill()
	reapplication_timer:resume()
end

function toggle()
	if active then
		active = false
		unset_blur()
		mp.unobserve_property(reset_blur)
	else
		active = true
		set_blur()
		local properties = { "osd-width", "osd-height", "path", "fullscreen" }
		for _, p in ipairs(properties) do
			mp.observe_property(p, "native", reset_blur)
		end
	end
end

if active then
	active = false
	toggle()
end

mp.add_key_binding(nil, "toggle-blur", toggle)
mp.add_key_binding(nil, "set-blur", set_blur)
mp.add_key_binding(nil, "unset-blur", unset_blur)