local class    = require('class')
local Config   = require('config')
local Event    = require('event')
local NFT      = require('nft')
local Packages = require('packages')
local SHA1     = require('sha1')
local Tween    = require('ui.tween')
local UI       = require('ui')
local Util     = require('util')

local colors     = _G.colors
local device     = _G.device
local fs         = _G.fs
local os         = _G.os
local pocket     = _G.pocket
local shell      = _ENV.shell
local term       = _G.term
local turtle     = _G.turtle

if not _ENV.multishell then
	error('multishell is required')
end

local REGISTRY_DIR = 'usr/.registry'
local DEFAULT_ICON = NFT.parse("\0308\0317\153\153\153\153\153\
\0307\0318\153\153\153\153\153\
\0308\0317\153\153\153\153\153")

UI:configure('Overview', ...)

local config = {
	Recent = { },
	currentCategory = 'Apps',
}
Config.load('Overview', config)

local extSupport = Util.getVersion() >= 1.76

local applications = { }
local buttons = { }

local sx, sy = term.current().getSize()
local maxRecent = math.ceil(sx * sy / 62)

local function ellipsis(s, len)
	if #s > len then
		s = s:sub(1, len - 2) .. '..'
	end
	return s
end

local function parseIcon(iconText)
	local icon

	local s, m = pcall(function()
		icon = NFT.parse(iconText)
		if icon then
			if icon.height > 3 or icon.width > 8 then
				error('Must be an NFT image - 3 rows, 8 cols max')
			end
		end
		return icon
	end)

	if s then
		return icon
	end

	return s, m
end

UI.VerticalTabBar = class(UI.TabBar)
function UI.VerticalTabBar:setParent()
	self.x = 1
	self.width = 8
	self.height = nil
	self.ey = -2
	UI.TabBar.setParent(self)
	for k,c in pairs(self.children) do
		c.x = 1
		c.y = k + 1
		c.ox, c.oy = c.x, c.y
		c.ow = 8
		c.width = 8
	end
end

local cx = 9
local cy = 1

local page = UI.Page {
	container = UI.Viewport {
		x = cx,
		y = cy,
	},
	tray = UI.Window {
		y = -1, width = 8,
		backgroundColor = colors.lightGray,
		newApp = UI.Button {
			text = '+', event = 'new',
		},
		--[[
		volume = UI.Button {
			x = 3,
			text = '\15', event = 'volume',
		},]]
	},
	editor = UI.SlideOut {
		y = -12, height = 12,
		backgroundColor = colors.cyan,
		titleBar = UI.TitleBar {
			title = 'Edit Application',
			event = 'slide_hide',
		},
		form = UI.Form {
			y = 2, ey = -2,
			[1] = UI.TextEntry {
				formLabel = 'Title', formKey = 'title', limit = 11, help = 'Application title',
				required = true,
			},
			[2] = UI.TextEntry {
				formLabel = 'Run', formKey = 'run', limit = 100, help = 'Full path to application',
				required = true,
			},
			[3] = UI.TextEntry {
				formLabel = 'Category', formKey = 'category', limit = 11, help = 'Category of application',
				required = true,
			},
			iconFile = UI.TextEntry {
				x = 11, ex = -12, y = 7,
				limit = 128, help = 'Path to icon file',
				shadowText = 'Path to icon file',
			},
			loadIcon = UI.Button {
				x = 11, y = 9,
				text = 'Load', event = 'loadIcon', help = 'Load icon file',
			},
			image = UI.NftImage {
				backgroundColor = colors.black,
				y = 7, x = 2, height = 3, width = 8,
			},
		},
		notification = UI.Notification(),
		statusBar = UI.StatusBar(),
	},
	notification = UI.Notification(),
	accelerators = {
		r = 'refresh',
		e = 'edit',
		f = 'files',
		s = 'shell',
		l = 'lua',
		[ 'control-n' ] = 'new',
		delete = 'delete',
	},
}

if extSupport then
	page.container.backgroundColor = colors.black
end

local function loadApplications()
	local requirements = {
		turtle = not not turtle,
		advancedTurtle = turtle and term.isColor(),
		advanced = term.isColor(),
		pocket = not not pocket,
		advancedPocket = pocket and term.isColor(),
		advancedComputer = not turtle and not pocket and term.isColor(),
		neuralInterface = not not device.neuralInterface,
	}

	applications = Util.readTable('sys/etc/apps.db')

	for dir in pairs(Packages:installed()) do
		local path = fs.combine('packages/' .. dir, 'etc/apps.db')
		if fs.exists(path) then
			local apps = Util.readTable(path) or { }
			Util.merge(applications, apps)
		end
	end

	if fs.exists(REGISTRY_DIR) then
		local files = fs.list(REGISTRY_DIR)
		for _,file in pairs(files) do
			local app = Util.readTable(fs.combine(REGISTRY_DIR, file))
			if app and app.key then
				app.filename = fs.combine(REGISTRY_DIR, file)
				applications[app.key] = app
			end
		end
	end

	Util.each(applications, function(v, k) v.key = k end)
	applications = Util.filter(applications, function(a)
		if a.disabled then
			return false
		end

		if a.requires then
			return requirements[a.requires]
		end

		return true -- Util.startsWith(a.run, 'http') or shell.resolveProgram(a.run)
	end)

	local categories = { }
	buttons = { }
	for _,f in pairs(applications) do
		if not categories[f.category] then
			categories[f.category] = true
			table.insert(buttons, {
				text = f.category,
				selected = config.currentCategory == f.category
			})
		end
	end
	table.sort(buttons, function(a, b) return a.text < b.text end)
	table.insert(buttons, 1, { text = 'Recent' })

	Util.removeByValue(page.children, page.tabBar)

	page:add {
		tabBar = UI.VerticalTabBar {
			buttons = buttons,
		},
	}

	--page.tabBar:selectTab(config.currentCategory or 'Apps')
	page.container:setCategory(config.currentCategory or 'Apps')
end

UI.Icon = class(UI.Window)
UI.Icon.defaults = {
	UIElement = 'Icon',
	width = 14,
	height = 4,
}
function UI.Icon:eventHandler(event)
	if event.type == 'mouse_click' then
		self:setFocus(self.button)
		--self:emit({ type = self.button.event, button = self.button })
		return true
	elseif event.type == 'mouse_doubleclick' then
		self:emit({ type = self.button.event, button = self.button })
	elseif event.type == 'mouse_rightclick' then
		self:setFocus(self.button)
		self:emit({ type = 'edit', button = self.button })
	end
	return UI.Window.eventHandler(self, event)
end

function page.container:setCategory(categoryName, animate)
	-- reset the viewport window
	self.children = { }
	self:reset()

	local function filter(it, f)
		local ot = { }
		for _,v in pairs(it) do
			if f(v) then
				table.insert(ot, v)
			end
		end
		return ot
	end

	local filtered

	if categoryName == 'Recent' then
		filtered = { }

		for _,v in ipairs(config.Recent) do
			local app = Util.find(applications, 'key', v)
			if app then -- and fs.exists(app.run) then
				table.insert(filtered, app)
			end
		end

	else
		filtered = filter(applications, function(a)
			return a.category == categoryName -- and fs.exists(a.run)
		end)
		table.sort(filtered, function(a, b) return a.title < b.title end)
	end

	for _,program in ipairs(filtered) do

		local icon
		if extSupport and program.iconExt then
			icon = parseIcon(program.iconExt)
		end
		if not icon and program.icon then
			icon = parseIcon(program.icon)
		end
		if not icon then
			icon = DEFAULT_ICON
		end

		local title = ellipsis(program.title, 8)

		local width = math.max(icon.width + 2, #title + 2)
		table.insert(self.children, UI.Icon({
			width = width,
			image = UI.NftImage({
				x = math.floor((width - icon.width) / 2) + 1,
				image = icon,
				width = 5,
				height = 3,
			}),
			button = UI.Button({
				x = math.floor((width - #title - 2) / 2) + 1,
				y = 4,
				text = title,
				backgroundColor = self.backgroundColor,
				backgroundFocusColor = colors.gray,
				textColor = colors.white,
				textFocusColor = colors.white,
				width = #title + 2,
				event = 'button',
				app = program,
			}),
		}))
	end

	local gutter = 2
	if UI.term.width <= 26 then
		gutter = 1
	end
	local col, row = gutter, 2
	local count = #self.children

	local r = math.random(1, 5)
	-- reposition all children
	for k,child in ipairs(self.children) do
		if r == 1 then
			child.x = math.random(1, self.width)
			child.y = math.random(1, self.height - 3)
		elseif r == 2 then
			child.x = self.width
			child.y = self.height - 3
		elseif r == 3 then
			child.x = math.floor(self.width / 2)
			child.y = math.floor(self.height / 2)
		elseif r == 4 then
			child.x = self.width - col
			child.y = row
		elseif r == 5 then
			child.x = col
			child.y = row
			if k == #self.children then
				child.x = self.width
				child.y = self.height - 3
			end
		end
		child.tween = Tween.new(6, child, { x = col, y = row }, 'linear')

		if not animate then
			child.x = col
			child.y = row
		end

		if k < count then
			col = col + child.width
			if col + self.children[k + 1].width + gutter - 2 > self.width then
				col = gutter
				row = row + 5
			end
		end
	end

	self:initChildren()
	if animate then
		local function transition()
			local i = 1
			return function()
				self:clear()
				for _,child in pairs(self.children) do
					child.tween:update(1)
					child.x = math.floor(child.x)
					child.y = math.floor(child.y)
					child:draw()
				end
				i = i + 1
				return i < 7
			end
		end
		self:addTransition(transition)
	end
end

function page:refresh()
	local pos = self.container.offy
	self:focusFirst(self)
	self.container:setCategory(config.currentCategory)
	self.container:setScrollPosition(pos)
end

function page:resize()
	UI.Page.resize(self)
	self:refresh()
end

function page:eventHandler(event)
	if event.type == 'tab_select' then
		self.container:setCategory(event.button.text, true)
		self.container:draw()

		config.currentCategory = event.button.text
		Config.update('Overview', config)

	elseif event.type == 'button' then
		for k,v in ipairs(config.Recent) do
			if v == event.button.app.key then
				table.remove(config.Recent, k)
				break
			end
		end
		table.insert(config.Recent, 1, event.button.app.key)
		if #config.Recent > maxRecent then
			table.remove(config.Recent, maxRecent + 1)
		end
		Config.update('Overview', config)
		shell.switchTab(shell.openTab(event.button.app.run))

	elseif event.type == 'shell' then
		shell.switchTab(shell.openTab('sys/apps/shell.lua'))

	elseif event.type == 'lua' then
		shell.switchTab(shell.openTab('sys/apps/Lua.lua'))

	elseif event.type == 'files' then
		shell.switchTab(shell.openTab('sys/apps/Files.lua'))

	elseif event.type == 'focus_change' then
		if event.focused.parent.UIElement == 'Icon' then
			event.focused.parent:scrollIntoView()
		end

	elseif event.type == 'refresh' then -- remove this after fixing notification
		loadApplications()
		self:refresh()
		self:draw()
		self.notification:success('Refreshed')

	elseif event.type == 'delete' then
		local focused = page:getFocused()
		if focused.app then
			if focused.app.filename then
				fs.delete(focused.app.filename)
			else
				focused.app.disabled = true
				local filename = focused.app.filename or fs.combine(REGISTRY_DIR, focused.app.key)
				Util.writeTable(filename, focused.app)
			end
			loadApplications()
			page:refresh()
			page:draw()
			self.notification:success('Removed')
		end

	elseif event.type == 'new' then
		local category = 'Apps'
		if config.currentCategory ~= 'Recent' then
			category = config.currentCategory or 'Apps'
		end
		self.editor:show({ category = category })

	elseif event.type == 'edit' then
		local focused = page:getFocused()
		if focused.app then
			self.editor:show(focused.app)
		end

	else
		UI.Page.eventHandler(self, event)
	end
	return true
end

function page.editor:show(app)
	if app then
		self.form:setValues(app)

		local icon
		if extSupport and app.iconExt then
			icon = parseIcon(app.iconExt)
		end
		if not icon and app.icon then
			icon = parseIcon(app.icon)
		end
		self.form.image:setImage(icon)
	end
	UI.SlideOut.show(self)
	self:focusFirst()
end

function page.editor.form.image:draw()
	self:clear()
	UI.NftImage.draw(self)
end

function page.editor:updateApplications(app)
	if not app.key then
		app.key = SHA1.sha1(app.title)
	end
	local filename = app.filename or fs.combine(REGISTRY_DIR, app.key)
	Util.writeTable(filename, app)
	loadApplications()
end

function page.editor:eventHandler(event)
	if event.type == 'form_cancel' or event.type == 'cancel' then
		self:hide()

	elseif event.type == 'focus_change' then
		self.statusBar:setStatus(event.focused.help or '')
		self.statusBar:draw()

	elseif event.type == 'loadIcon' then
		local s, m = pcall(function()
			local iconLines = Util.readFile(self.form.iconFile.value)
			if not iconLines then
				error('Must be an NFT image - 3 rows, 8 cols max')
			end
			local icon, m = parseIcon(iconLines)
			if not icon then
				error(m)
			end
			if extSupport then
				self.form.values.iconExt = iconLines
			else
				self.form.values.icon = iconLines
			end
			self.form.image:setImage(icon)
			self.form.image:draw()
		end)
		if not s and m then
			local msg = m:gsub('.*: (.*)', '%1')
			self.notification:error(msg)
		end

	elseif event.type == 'form_invalid' then
		self.notification:error(event.message)

	elseif event.type == 'form_complete' then
		local values = self.form.values
		self:hide()
		self:updateApplications(values)
		--page:refresh()
		--page:draw()
		config.currentCategory = values.category
		Config.update('Overview', config)
		os.queueEvent('overview_refresh')
	else
		return UI.SlideOut.eventHandler(self, event)
	end
	return true
end

UI:setPages({
	main = page,
})

local function reload()
	loadApplications()
	page:refresh()
	page:draw()
	page:sync()
end

Event.on('overview_shortcut', function(_, app)
	if not app.key then
		app.key = SHA1.sha1(app.title)
	end
	local filename = app.filename or fs.combine(REGISTRY_DIR, app.key)
	if not fs.exists(filename) then
		Util.writeTable(filename, app)
		reload()
	end
end)

Event.on('overview_refresh', function()
	reload()
end)

loadApplications()

UI:setPage(page)

UI:pullEvents()