decode-gpg.lua

local gpgGroup = vim.api.nvim_create_augroup("customGpg", { clear = true })

vim.api.nvim_create_autocmd({ "BufReadPre", "FileReadPre" }, {
	pattern = "*.gpg",
	group = gpgGroup,
	callback = function()
		-- Make sure nothing is written to shada file while editing an encrypted file.
		vim.opt_local.shada = nil
		-- We don't want a swap file, as it writes unencrypted data to disk
		vim.opt_local.swapfile = false
		-- Switch to binary mode to read the encrypted file
		vim.opt_local.bin = true
		-- Save the current 'ch' value to a buffer-local variable
		vim.b.ch_save = vim.opt_local.ch:get()
		vim.cmd "set ch=2"
	end,
})

vim.api.nvim_create_autocmd({ "BufReadPost", "FileReadPost" }, {
	pattern = "*.gpg",
	group = gpgGroup,
	callback = function()
		vim.cmd "'[,']!gpg -d 2> /dev/null"
		-- Switch to normal mode for editing
		vim.opt_local.bin = false
		-- Restore the 'ch' value from the buffer-local variable
		vim.opt_local.ch = vim.b.ch_save
		vim.cmd "unlet b:ch_save"
		vim.cmd(":doautocmd BufReadPost " .. vim.fn.expand "%:r")
	end,
})

-- Convert all text to encrypted text before writing
vim.api.nvim_create_autocmd({ "BufWritePre", "FileWritePre" }, {
	pattern = "*.gpg",
	group = gpgGroup,
	callback = function()
		-- Switch to binary mode to write the encrypted file
		vim.opt_local.bin = true
		-- So we can avoid the armor option
		vim.cmd("'[,']!gpg -e 2>/dev/null")
	end,
})
-- Undo the encryption so we are back in the normal text, directly after the file has been written.
vim.api.nvim_create_autocmd({ "BufWritePost", "FileWritePost" }, {
	pattern = "*.gpg",
	group = gpgGroup,
	callback = function()
		vim.cmd("u")
		-- Switch to normal mode for editing
		vim.opt_local.bin = false
	end,
})

-- Return an empty table to satisfy plugin loader requirements
return {}