nix-dotfiles/home-manager/nvim/init.lua

vim.g.python3_host_prog = "%PYTHONENV%/bin/python"
vim.opt.mouse = ""
vim.opt.history = 500
vim.opt.background = "dark"

vim.opt.wildmenu = true
vim.opt.wildignore = vim.opt.wildignore + { "*/.git/*", "*/.hg/*", "*/.svn/*", "*/.DS_Store" }

vim.opt.ignorecase = true
vim.opt.smartcase = true
vim.opt.incsearch = true
vim.opt.magic = true
vim.opt.hlsearch = true

vim.opt.autoindent = true
vim.opt.smartindent = true

vim.opt.wrap = true
vim.opt.linebreak = true
vim.opt.textwidth = 500

vim.opt.switchbuf = "useopen"

vim.opt.laststatus = 2
-- I don't use tabs, but one day I might!
vim.opt.showtabline = 2

vim.opt.langmenu = "en"

vim.opt.ffs = "unix"
vim.opt.encoding = "utf8"

-- Always show current position
vim.opt.ruler = true
vim.opt.number = true

-- A bit of extra margin to the left
vim.opt.foldcolumn = "1"

vim.opt.autoread = true
vim.opt.backup = false
vim.opt.writebackup = true
vim.opt.swapfile = false

vim.opt.cmdheight = 2

-- Use spaces instead of tabs
vim.opt.expandtab = true
vim.opt.smarttab = true
vim.opt.shiftwidth = 4
vim.opt.tabstop = 4

vim.opt.lazyredraw = true

-- Show matching brackets when text indicator is on one of them
vim.opt.showmatch = true
vim.opt.mat = 2

-- Turn off sound
vim.opt.errorbells = false
vim.opt.visualbell = false

vim.opt.timeoutlen = 500

vim.opt.scrolloff = 2

-- Return to last edit position when opening files
vim.api.nvim_create_autocmd("BufReadPost", {
	pattern = "*",
	callback = function()
		local line = vim.fn.line
		local last_pos = line("'\"")
		if last_pos > 1 and last_pos <= line("$") then
			vim.cmd("normal! g'\"")
		end
	end,
})

-- Trim trailing whitespace on save
function CleanExtraSpaces()
	local save_cursor = vim.api.nvim_win_get_cursor(0)
	local old_query = vim.fn.getreg("/")
	vim.cmd("%s/\\s\\+$//e")
	vim.api.nvim_win_set_cursor(0, save_cursor)
	vim.fn.setreg("/", old_query)
end
vim.api.nvim_create_autocmd("BufWritePre", {
	pattern = { "*.fs", "*.fsi", "*.txt", "*.js", "*.py", "*.wiki", "*.sh", "*.coffee" },
	callback = CleanExtraSpaces,
})

-- Status line

-- Returns true if paste mode is enabled
function HasPaste()
	if vim.opt.paste:get() then
		return "PASTE MODE  "
	end
	return ""
end

vim.o.statusline = vim.o.statusline .. "%{v:lua.HasPaste()}%F%m%r%h %w  CWD: %r%{getcwd()}%h   Line: %l  Column: %c"

--------------------------------------------------------------

vim.api.nvim_set_keymap("n", ";", "<Nop>", { noremap = true })
vim.api.nvim_set_var("maplocalleader", ";")

function MarkdownPreview()
	local temp_file = vim.fn.tempname() .. ".md"
	local file_name = vim.fn.substitute(vim.fn.tolower(vim.fn.expand("%:t")), "\\W", "_", "g")
	local temp_html = "/tmp/" .. file_name .. "_tmp.html"

	-- Write the current buffer to the temp file
	vim.cmd("write! " .. temp_file)

	local pandoc_cmd = "pandoc " .. temp_file .. " -o " .. temp_html

	-- Execute the pandoc command
	vim.fn.system(pandoc_cmd)

	-- Use tmux and lynx to preview the HTML file
	local lynx_cmd = "tmux split-window -h lynx " .. temp_html
	vim.fn.jobstart(vim.split(lynx_cmd, " "), { silent = true })

	-- Delete the temp markdown file
	vim.fn.delete(temp_file, "rf")
end

function RemoveCarriageReturn()
	vim.cmd("mark m")
	vim.cmd("normal! Hmt")
	vim.cmd("%s/\r//ge")
	vim.cmd("normal! 'tzt'm")
end

function FormatJson()
	vim.cmd("%!python -m json.tool")
end

function ChangeToCurrentDirectory()
	vim.cmd(":cd %:p:h")
	vim.cmd(":pwd")
end

local function close_loclist_if_orphaned()
	local win = vim.fn.expand("<afile>")
	vim.fn.win_execute(win, "lclose")
end

-- Set up an autocmd using the nvim_create_autocmd API
vim.api.nvim_create_autocmd("WinClosed", {
	pattern = "*",
	callback = close_loclist_if_orphaned,
})

local status, whichkey = pcall(require, "which-key")
if status then
	local pickers = require("telescope.pickers")
	local action_state = require("telescope.actions.state")
	local actions = require("telescope.actions")
	local finders = require("telescope.finders")
	local conf = require("telescope.config").values

	function DisplayAllMappingsWithTelescope()
		local mappings = {}
		local commands = {} -- Store commands keyed by the display string

		require("which-key.keys").get_tree("n").tree:walk(function(node)
			if node.mapping then
				local mapping = node.mapping
				local description = mapping.desc or mapping.label or mapping.cmd
				-- Some actions are just there for which-key to hook into to display prefixes; they don't have a description.
				if description then
					local displayString = description .. " | " .. mapping.prefix
					commands[displayString] = mapping.prefix
					mappings[#mappings + 1] = displayString
				end
				-- TODO: If a command is a prefix of an existing command, prepend its description to those commands' descriptions, and append a '...' to the parent's description.
			end
		end)

		pickers
			.new({}, {
				prompt_title = "Actions",
				finder = finders.new_table({
					results = mappings,
				}),
				sorter = conf.generic_sorter({}),
				attach_mappings = function(_, map)
					map("i", "<CR>", function(bufnr)
						local selection = action_state.get_selected_entry()
						actions.close(bufnr)
						local cmd = commands[selection.value]
						if cmd then
							vim.api.nvim_command(":normal " .. vim.api.nvim_replace_termcodes(cmd, true, true, true))
						else
							print("no command found")
						end
					end)
					return true
				end,
			})
			:find()
	end

	function ToggleSpell()
		vim.cmd("setlocal spell!")
	end

	vim.api.nvim_set_keymap("n", "<localleader><localleader>", ":lua DisplayAllMappingsWithTelescope()<CR>", {})
	whichkey.register({
		["mp"] = {
			MarkdownPreview,
			"Preview Markdown in Lynx",
		},
		["md"] = {
			RemoveCarriageReturn,
			"Delete carriage returns from file",
		},
		["j"] = {
			FormatJson,
			"Auto-format JSON",
		},
		["cd"] = {
			ChangeToCurrentDirectory,
			"Switch CWD to the directory of the open buffer",
		},
		-- For some reason the command doesn't work at all if I map it in here,
		-- whereas if we map it separately and *document* it in here then only the documentation doesn't work.
		[vim.api.nvim_get_var("maplocalleader")] = {
			"View all mappings",
		},
		["ss"] = {
			ToggleSpell,
			"Toggle spell-checker on or off",
		},
	}, { prefix = vim.api.nvim_get_var("maplocalleader") })
else
	vim.api.nvim_set_keymap("n", "<localleader>mp", ":lua MarkdownPreview()<CR>", { noremap = true, silent = true })
	-- Remove the Windows ^M - when the encodings gets messed up
	vim.api.nvim_set_keymap("n", "<localleader>md", ":lua RemoveCarriageReturn()<CR>", { noremap = true })
	vim.api.nvim_set_keymap("n", "<localleader>j", ":lua FormatJson()<CR>", { noremap = true })
	vim.api.nvim_set_keymap("n", "<localleader>cd", ":lua ChangeToCurrentDirectory()<CR>", { noremap = true })
end