local native = require('codemp.loader').load()

local utils = require('codemp.utils')
local buffers = require('codemp.buffer')
local async = require('codemp.async')

local user_hl = {}
local available_colors = { -- TODO these are definitely not portable!
	"ErrorMsg",
	"WarningMsg",
	"MatchParen",
	"SpecialMode",
	"CmpItemKindFunction",
	"CmpItemKindValue",
	"CmpItemKindInterface",
}

local function register_cursor_callback(controller, workspace, buffer)
	vim.api.nvim_create_autocmd({"CursorMoved", "CursorMovedI", "ModeChanged"}, {
		group = vim.api.nvim_create_augroup("codemp-workspace-" .. workspace, { clear = true }),
		callback = function (_)
			local cur = utils.cursor.position()
			local buf = buffer or vim.api.nvim_get_current_buf()
			if buffers.map[buf] ~= nil then
				controller:send(buffers.map[buf], cur[1][1], cur[1][2], cur[2][1], cur[2][2])
			end
		end
	})
end

local function register_cursor_handler(controller, workspace)
	async.handler(workspace, nil, controller, function(event)
		if user_hl[event.user] == nil then
			user_hl[event.user] = {
				ns = vim.api.nvim_create_namespace("codemp-cursor-" .. event.user),
				hi = available_colors[ math.random( #available_colors ) ],
			}
		end
		local buffer = buffers.map_rev[event.position.buffer]
		if buffer ~= nil then
			vim.api.nvim_buf_clear_namespace(buffer, user_hl[event.user].ns, 0, -1)
			utils.multiline_highlight(
				buffer,
				user_hl[event.user].ns,
				user_hl[event.user].hi,
				event.position.start,
				event.position.finish
			)
		end
	end, 20)
end

local function join(workspace)
	local controller = native.join_workspace(workspace)
	register_cursor_callback(controller, workspace)
	register_cursor_handler(controller, workspace)
	print(" ++ joined workspace " .. workspace)
end

local function leave()
	native.leave_workspace()
	print(" -- left workspace")
end

local function list_users(workspace)
	local workspace = native.get_workspace(workspace)
	for _, buffer in pairs(workspace.users) do
		print(" - " .. buffer)
	end
end

local function list_buffers(workspace)
	return native.get_workspace(workspace).filetree
end

return {
	join = join,
	leave = leave,
	buffers = list_buffers,
	users = list_users,
	map = user_hl,
	colors = available_colors,
}