-- Greenhouse is a simple text scrolling handler for terminal programs.
-- The idea is that it can be set a region to do its scrolling and paging
-- job and then the user can draw whatever outside it.
-- This reduces code duplication for the message viewer
-- and flowerbook.

local ansikit = require 'ansikit'
local terminal = require 'terminal'
local Object = require 'nature.object'

local Greenhouse = Object:extend()

function Greenhouse:new(sink)
	local size = terminal.size()
	self.region = size
	self.start = 1
	self.offset = 1
	self.sink = sink
	self.pages = {}
	self.curPage = 1

	return self
end

function Greenhouse:addPage(page)
	table.insert(self.pages, page)
end

function Greenhouse:updateCurrentPage(text)
	local page = self.pages[self.curPage]
	page:setText(text)
end

function Greenhouse:draw()
	local lines = self.pages[self.curPage].lines
	self.sink:write(ansikit.getCSI(self.start .. ';1', 'H'))
	self.sink:write(ansikit.getCSI(2, 'J'))

	-- the -2 negate is for the command and status line
	for i = self.offset, self.offset + (self.region.height - self.start) - 2 do
		if i > #lines then break end
		self.sink:writeln('\r' .. lines[i]:gsub('\t', '        '):sub(0, self.region.width - 2))
	end
	self.sink:write '\r'

	self.sink:write(ansikit.getCSI(self.region.height - self.start.. ';1', 'H'))
	self.sink:writeln(string.format('\27[0mPage %d', self.curPage))
end

function Greenhouse:scroll(direction)
	local lines = self.pages[self.curPage].lines

	local oldOffset = self.offset
	if direction == 'down' then
		self.offset = math.min(self.offset + 1, #lines)
	elseif direction == 'up' then
		self.offset = math.max(self.offset - 1, 1)
	end

	if self.offset ~= oldOffset then self:draw() end
end

function Greenhouse:update()
	local size = terminal.size()
	self.region = size

	self:draw()
end

function Greenhouse:next()
	local oldCurrent = self.curPage
	self.curPage = math.min(self.curPage + 1, #self.pages)
	if self.curPage ~= oldCurrent then
		self.offset = 1
		self:draw()
	end
end

function Greenhouse:previous()
	local oldCurrent = self.curPage
	self.curPage = math.max(self.curPage - 1, 1)
	if self.curPage ~= oldCurrent then
		self.offset = 1
		self:draw()
	end
end

function Greenhouse:initUi()
	local ansikit = require 'ansikit'
	local bait = require 'bait'
	local commander = require 'commander'
	local hilbish = require 'hilbish'
	local terminal = require 'terminal'
	local Page = require 'nature.greenhouse.page'
	local done = false

	bait.catch('signal.sigint', function()
		ansikit.clear()
		done = true
	end)

	bait.catch('signal.resize', function()
		self:update()
	end)

	ansikit.screenAlt()
	ansikit.clear(true)
	self:draw()

	hilbish.goro(function()
		while not done do
			local c = read()
			if c == 3 then
				done = true
			end

			if c == 27 then
				local c1 = read()
				if c1 == 91 then
					local c2 = read()
					if c2 == 66 then -- arrow down
						self:scroll 'down'
					elseif c2 == 65 then -- arrow up
						self:scroll 'up'
					end

					if c2 == 49 then
						local c3 = read()
						if c3 == 59 then
							local c4 = read()
							if c4 == 53 then
								local c5 = read()
								if c5 == 67 then
									self:next()
								elseif c5 == 68 then
									self:previous()
								end
							end
						end
					end
				end
				goto continue
			end
			print('\nchar:')
			print(c)

			::continue::
		end
	end)

	while not done do
		--
	end
	ansikit.screenMain()
end

function read()
	terminal.saveState()
	terminal.setRaw()
	local c = io.read(1)

	terminal.restoreState()
	return c:byte()
end

return Greenhouse