local orig = {}

local function parse(line)
	local prefix, name = line:match('^([| ]*)(.-)%s*$')
	local _, depth = prefix:gsub('|', '')
	return depth, name
end

local function open_entry()
	local buf = vim.api.nvim_get_current_buf()
	local lnum = vim.fn.line('.')
	local depth, name = parse(vim.fn.getline(lnum))

	local function fallback()
		local rhs = orig[buf] and orig[buf].rhs
		if rhs and rhs ~= '' then
			vim.api.nvim_feedkeys(vim.keycode(rhs), 'n', false)
		end
	end

	if name == '' or name:sub(-1) == '/' or depth == 0 then
		return fallback()
	end

	local parts, cur, top = {}, depth, nil
	for l = lnum - 1, 1, -1 do
		local d, n = parse(vim.fn.getline(l))
		if n ~= '' and d < cur and n:sub(-1) == '/' then
			if d == 0 then
				top = n
				break
			end
			table.insert(parts, 1, n)
			cur = d
		end
	end

	if not top or not top:match('^%a+://') then
		return fallback()
	end

	vim.cmd('edit ' .. vim.fn.fnameescape(top .. table.concat(parts) .. name))
end

local function install(buf)
	local m = vim.fn.maparg('<CR>', 'n', false, true)
	if m.callback then return end
	orig[buf] = m
	vim.keymap.set('n', '<CR>', open_entry, { buffer = buf, silent = true })
end

vim.api.nvim_create_autocmd({ 'BufEnter', 'CursorMoved' }, {
	callback = function(a)
		if vim.bo[a.buf].filetype == 'netrw' and vim.g.netrw_liststyle == 3 then
			install(a.buf)
		end
	end,
})

local pending = {}

local function parse_url(url)
	local host, path = url:match('^s[cf]tp://([^/]+)/(.*)$')
	if not host then return end
	local port
	local h, p = host:match('^(.+):(%d+)$')
	if h then host, port = h, p end
	return host, port, path
end

local function upload(a)
	local buf, url = a.buf, a.match
	local host, port, path = parse_url(url)
	if not host then
		vim.notify('cannot parse ' .. url, vim.log.levels.ERROR)
		return
	end

	local tmp = vim.fn.tempname()
	vim.fn.writefile(vim.api.nvim_buf_get_lines(buf, 0, -1, false), tmp)

	local cmd = { 'scp', '-q', '-o', 'BatchMode=yes' }
	if port then vim.list_extend(cmd, { '-P', port }) end
	vim.list_extend(cmd, { tmp, host .. ':' .. path })

	local name = vim.fn.fnamemodify(url, ':t')
	vim.bo[buf].modified = false

	local id = #pending + 1
	pending[id] = vim.system(cmd, { text = true }, function(res)
		pending[id] = false
		os.remove(tmp)
		vim.schedule(function()
			if res.code == 0 then
				vim.notify(name .. ': uploaded')
			else
				if vim.api.nvim_buf_is_valid(buf) then
					vim.bo[buf].modified = true
				end
				local err = (vim.trim(res.stderr or ''):gsub('%s*\n%s*', ' '))
				vim.notify(name .. ': upload failed: ' .. err, vim.log.levels.ERROR)
			end
		end)
	end)
end

for _, pat in ipairs({ 'scp://*', 'sftp://*' }) do
	pcall(vim.api.nvim_clear_autocmds, { event = 'BufWriteCmd', pattern = pat })
end

vim.api.nvim_create_autocmd('BufWriteCmd', {
	pattern = { 'scp://*', 'sftp://*' },
	callback = upload,
})

vim.api.nvim_create_autocmd('VimLeavePre', {
	callback = function()
		for _, obj in pairs(pending) do
			if obj then obj:wait() end
		end
	end,
})