codemp-nvim/lua/codemp/buffers.lua

local utils = require('codemp.utils')
local session = require('codemp.session')

---@type table<integer, string>
local id_buffer_map = {}
---@type table<string, integer>
local buffer_id_map = {}
---@type table<string, string>
local user_buffer_name = {}
local ticks = {}

---@param name string name of buffer to attach to
---@param buffer integer buffer to use for attaching (will clear content)
---@param content? string if provided, set this content after attaching
---@param nowait? boolean skip waiting for initial content sync
---@return BufferController
local function attach(name, buffer, content, nowait)
	if buffer_id_map[name] ~= nil then
		error("already attached to buffer " .. name)
	end
	vim.api.nvim_set_option_value('fileformat', 'unix', { buf = buffer })
	vim.api.nvim_buf_set_name(buffer, name)
	local controller = session.workspace:attach_buffer(name):await()

	if not nowait then
		local promise = controller:poll()
		for i=1, 20, 1 do
			if promise.ready then break end
			vim.uv.sleep(100)
		end
	end

	-- TODO map name to uuid

	id_buffer_map[buffer] = name
	buffer_id_map[name] = buffer
	ticks[buffer] = 0

	-- hook serverbound callbacks
	-- TODO breaks when deleting whole lines at buffer end
	vim.api.nvim_buf_attach(buffer, false, {
		on_bytes = function(_, buf, tick, start_row, start_col, start_offset, old_end_row, old_end_col, old_end_byte_len, new_end_row, new_end_col, new_byte_len)
			if tick <= ticks[buf] then return end
			if id_buffer_map[buf] == nil then return true end -- unregister callback handler
			if CODEMP.config.debug then print(string.format(
				"start(row:%s, col:%s) offset:%s end(row:%s, col:%s new(row:%s, col:%s)) len(old:%s, new:%s)",
				start_row, start_col, start_offset, old_end_row, old_end_col, new_end_row, new_end_col, old_end_byte_len, new_byte_len
			)) end
			local end_offset = start_offset + old_end_byte_len
			local change_content = ""
			local len = utils.buffer.len(buf)
			if start_offset + new_byte_len + 1 > len then
				-- i dont know why but we may go out of bounds when doing 'dd' at the end of buffer??
				local delta = (start_offset + new_byte_len + 1) - len
				if CODEMP.config.debug then print("/!\\ bytes out of bounds by " .. delta .. ", adjusting") end
				end_offset = end_offset - delta
				start_offset = start_offset - delta
			end
			if new_byte_len > 0 then
				local actual_end_col = new_end_col
				if new_end_row == 0 then actual_end_col = new_end_col + start_col end
				local actual_end_row = start_row + new_end_row
				-- -- when bulk inserting at the end we go out of bounds, so we probably need to clamp?
				-- --  issue: row=x+1 col=0 and row=x col=0 may be very far apart! we need to get last col of row x, ughh..
				-- -- also, this doesn't work so it will stay commented out for a while longer
				-- if new_end_row ~= old_end_row and new_end_col == 0 then
				-- 	-- we may be dealing with the last line of the buffer, get_text could error because out-of-bounds
				-- 	local row_count = vim.api.nvim_buf_line_count(buf)
				-- 	if actual_end_row + 1 > row_count then
				-- 		local delta = (actual_end_row + 1) - row_count
				-- 		if CODEMP.config.debug then print("/!\\ row out of bounds by " .. delta .. ", adjusting") end
				-- 		actual_end_row = actual_end_row - delta
				-- 		actual_end_col = len - vim.api.nvim_buf_get_offset(buf, row_count)
				-- 	end
				-- end
				local lines = vim.api.nvim_buf_get_text(buf, start_row, start_col, actual_end_row, actual_end_col, {})
				change_content = table.concat(lines, '\n')
			end
			if CODEMP.config.debug then
				print(string.format("sending: %s..%s '%s'", start_offset, start_offset + old_end_byte_len, change_content))
			end
			controller:send(start_offset, end_offset, change_content):await()
		end,
	})

	local async = vim.loop.new_async(vim.schedule_wrap(function ()
		while true do
			local event = controller:try_recv():await()
			if event == nil then break end
			ticks[buffer] = vim.api.nvim_buf_get_changedtick(buffer)
			if CODEMP.config.debug then
				print(" ~~ applying change ~~ " .. event.first .. ".." .. event.last .. "::[" .. event.content .. "]")
			end
			utils.buffer.set_content(buffer, event.content, event.first, event.last)
			if event.hash ~= nil then
				if utils.hash(utils.buffer.get_content(buffer)) ~= event.hash then
					-- OUT OF SYNC!
					-- TODO this may be destructive! we should probably prompt the user before doing this
					print(" /!\\ out of sync, resynching...")
					utils.buffer.set_content(buffer, controller:content():await())
					return
				end
			end
		end
	end))

	local remote_content = controller:content():await()
	if content ~= nil then
		-- TODO this may happen too soon!!
		local _ = controller:send(0, #remote_content, content) -- no need to await
	else
		local current_content = utils.buffer.get_content(buffer)
		if current_content ~= remote_content then
			ticks[buffer] = vim.api.nvim_buf_get_changedtick(buffer)
			utils.buffer.set_content(buffer, remote_content)
		end
	end

	controller:callback(function (_controller) async:send() end)
	vim.defer_fn(function() async:send() end, 500) -- force a try_recv after 500ms

	local filetype = vim.filetype.match({ buf = buffer })
	vim.api.nvim_set_option_value("filetype", filetype, { buf = buffer })
	print(" ++ attached to buffer " .. name)
	require('codemp.window').update()
	return controller
end

---@param name string
--TODO this should happen at the level above (Workspace) but accesses tables on this level, badly designed!
local function detach(name)
	local buffer = buffer_id_map[name]
	id_buffer_map[buffer] = nil
	buffer_id_map[name] = nil
	session.workspace:detach_buffer(name)
	vim.api.nvim_buf_delete(buffer, {})

	print(" -- detached from buffer " .. name)
	require('codemp.window').update()
end

---@param buffer? integer if provided, sync given buffer id, otherwise sync current buf
local function sync(buffer)
	if buffer == nil then
		buffer = vim.api.nvim_get_current_buf()
	end
	local name = id_buffer_map[buffer]
	if name ~= nil then
		local controller = session.workspace:get_buffer(name)
		if controller ~= nil then
			local real_content = controller:content():await()
			local my_content = utils.buffer.get_content(buffer)
			if real_content ~= my_content then
				ticks[buffer] = vim.api.nvim_buf_get_changedtick(buffer)
				utils.buffer.set_content(buffer, real_content)
				print(" !! re-synched buffer " .. name)
			else
				print(" :: buffer " .. name .. " is in sync")
			end
			return
		end
	end

	print(" !! buffer not managed")
end

local function create(buffer)
	if buffer == nil then
		buffer = vim.fn.expand("%p")
	end
	if session.workspace == nil then
		error("join a workspace first")
	end
	session.workspace:create_buffer(buffer):await()
	print(" ++  created buffer " .. buffer)
	require('codemp.window').update()
end

return {
	sync = sync,
	attach = attach,
	detach = detach,
	create = create,
	map = id_buffer_map,
	map_rev = buffer_id_map,
	ticks = ticks,
	users = user_buffer_name,
}