-- ~/.config/vis/fzf.lua
-- Pickers: fuzzy file finder, live ripgrep, terminal file manager.
-- Loaded from visrc.lua. Each function is self-contained on purpose.

local M = {}

-- height of the drop-down fzf panel at the top ('100%' = full screen)
M.height = '50%'

-- ---------------------------------------------------------------------------
-- files: fuzzy-find a file, or create one from the query
--   enter   open the highlighted file (or create the query if nothing matches)
--   ctrl-n  new file named after the query, e.g. src/util/new.odin
-- ---------------------------------------------------------------------------
function M.files()
	-- file list: fd, fdfind (Debian/Ubuntu), or plain find
	local list = "find . -type f -not -path '*/.git/*' | sed 's|^\\./||'"
	for _, name in ipairs({ 'fd', 'fdfind' }) do
		local ok = os.execute('command -v ' .. name .. ' >/dev/null 2>&1')
		if ok == true or ok == 0 then
			list = name .. ' --type f --hidden --exclude .git'
			break
		end
	end

	-- preview: bat, batcat (Debian/Ubuntu), or head
	local preview = 'head -n 500 {}'
	for _, name in ipairs({ 'bat', 'batcat' }) do
		local ok = os.execute('command -v ' .. name .. ' >/dev/null 2>&1')
		if ok == true or ok == 0 then
			preview = name .. ' --color=always --style=numbers --line-range=:500 {}'
			break
		end
	end

	local cmd = list .. ' | fzf'
		.. ' --height=' .. M.height .. ' --layout=reverse --border'
		.. " --prompt 'files> '"
		.. ' --print-query --expect=ctrl-n'   -- line 1: query, line 2: key
		.. " --header 'enter: open · ctrl-n: new file from query'"
		.. " --preview '" .. preview .. "'"
		.. " --preview-window 'right:60%:border-left'"
		.. " --bind 'ctrl-/:toggle-preview'"
		.. " --bind 'shift-up:preview-up,shift-down:preview-down'"

	-- fzf's --height mode draws from the cursor down: start at the top-left
	local tty = io.open('/dev/tty', 'w')
	if tty then tty:write('\27[H') tty:close() end

	local handle = io.popen(cmd)
	if not handle then
		vis:info('fzf: failed to start')
		return
	end
	local out = {}
	for line in handle:lines() do table.insert(out, line) end
	local _, _, code = handle:close()

	-- back onto the alternate screen (so quitting vis restores the
	-- terminal), then repaint vis
	tty = io.open('/dev/tty', 'w')
	if tty then tty:write('\27[?1049h') tty:close() end
	vis:redraw()

	if code == 130 then return end  -- Esc / Ctrl-C

	local query, key, choice = out[1], out[2], out[3]
	local is_new = key == 'ctrl-n' or not choice or choice == ''
	local path = is_new and query or choice
	if not path or path == '' then return end

	-- open in the current window, unless it's already the current file
	local win = vis.win
	local current = win and win.file and win.file.path
	local same = current ~= nil
		and (current == path or current:sub(-#path - 1) == '/' .. path)
	if not same then
		if win and win.file and win.file.modified then
			vis:info('Buffer has unsaved changes — :w first (or use :e! manually)')
			return
		end
		vis:command(string.format("e '%s'", path))
	end

	if is_new then
		vis:info('New file: ' .. path .. ' (written to disk on :w)')
	end
end

-- ---------------------------------------------------------------------------
-- grep: live ripgrep search across the project, jump to the match
-- ---------------------------------------------------------------------------
function M.grep()
	local ok = os.execute('command -v rg >/dev/null 2>&1')
	if not (ok == true or ok == 0) then
		vis:info('ripgrep (rg) not found on PATH')
		return
	end

	-- preview: bat/batcat with the match highlighted, or cat -n
	-- {1} = path, {2} = line number (fields split on ':')
	local preview = 'cat -n {1}'
	for _, name in ipairs({ 'bat', 'batcat' }) do
		local found = os.execute('command -v ' .. name .. ' >/dev/null 2>&1')
		if found == true or found == 0 then
			preview = name .. ' --color=always --style=numbers --highlight-line {2} {1}'
			break
		end
	end

	-- don't run rg on an empty query (it would match every line)
	local reload = '[ -n {q} ] && rg --column --line-number --no-heading'
		.. ' --color=always --smart-case --hidden --glob "!.git" -- {q} || true'

	-- empty stdin: results only appear once you start typing
	local cmd = ': | fzf'
		.. ' --height=' .. M.height .. ' --layout=reverse --border'
		.. " --prompt 'rg> '"
		.. ' --ansi --disabled'               -- let rg do the matching, not fzf
		.. ' --delimiter :'
		.. " --bind 'change:reload:" .. reload .. "'"
		.. " --preview '" .. preview .. "'"
		.. " --preview-window 'right:60%:border-left:+{2}/2'"  -- centre match
		.. " --bind 'ctrl-/:toggle-preview'"
		.. " --bind 'shift-up:preview-up,shift-down:preview-down'"

	-- fzf's --height mode draws from the cursor down: start at the top-left
	local tty = io.open('/dev/tty', 'w')
	if tty then tty:write('\27[H') tty:close() end

	local handle = io.popen(cmd)
	if not handle then
		vis:info('fzf: failed to start')
		return
	end
	local choice = handle:read('*l')
	handle:close()

	-- back onto the alternate screen, then repaint vis
	tty = io.open('/dev/tty', 'w')
	if tty then tty:write('\27[?1049h') tty:close() end
	vis:redraw()

	if not choice or choice == '' then return end

	choice = choice:gsub('\27%[[%d;]*m', '')  -- strip any colour codes
	local path, line, col = choice:match('^(.-):(%d+):(%d+):')
	if not path then return end

	-- open in the current window, unless it's already the current file
	local win = vis.win
	local current = win and win.file and win.file.path
	local same = current ~= nil
		and (current == path or current:sub(-#path - 1) == '/' .. path)
	if not same then
		if win and win.file and win.file.modified then
			vis:info('Buffer has unsaved changes — :w first (or use :e! manually)')
			return
		end
		vis:command(string.format("e '%s'", path))
	end

	vis.win.selection:to(tonumber(line), tonumber(col))
end

-- ---------------------------------------------------------------------------
-- fm: browse/create/rename/delete in a terminal file manager, then open the
-- file you pick. Uses the first one found: yazi, lf, nnn, ranger
-- ---------------------------------------------------------------------------
function M.fm()
	local tmp = os.tmpname()
	local managers = {
		{ 'yazi',   "yazi --chooser-file='%s'" },
		{ 'lf',     "lf -selection-path '%s'" },
		{ 'nnn',    "nnn -p '%s'" },
		{ 'ranger', "ranger --choosefile='%s'" },
	}

	local cmd
	for _, m in ipairs(managers) do
		local ok = os.execute('command -v ' .. m[1] .. ' >/dev/null 2>&1')
		if ok == true or ok == 0 then
			cmd = string.format(m[2], tmp)
			break
		end
	end
	if not cmd then
		os.remove(tmp)
		vis:info('No file manager found (install yazi, lf, nnn or ranger)')
		return
	end

	os.execute(cmd .. ' </dev/tty >/dev/tty 2>&1')

	-- back onto the alternate screen, then repaint vis
	local tty = io.open('/dev/tty', 'w')
	if tty then tty:write('\27[?1049h') tty:close() end
	vis:redraw()

	local f = io.open(tmp, 'r')
	local path = f and f:read('*l')
	if f then f:close() end
	os.remove(tmp)
	if not path or path == '' then return end

	-- open in the current window, unless it's already the current file
	local win = vis.win
	local current = win and win.file and win.file.path
	if current ~= path then
		if win and win.file and win.file.modified then
			vis:info('Buffer has unsaved changes — :w first (or use :e! manually)')
			return
		end
		vis:command(string.format("e '%s'", path))
	end
end

-- ---------------------------------------------------------------------------
-- create missing parent directories on save, so a new file from ctrl-n like
-- src/util/new.odin can be written even if src/util/ doesn't exist yet
-- ---------------------------------------------------------------------------
vis.events.subscribe(vis.events.FILE_SAVE_PRE, function(file, path) -- luacheck: no unused args
	local dir = path and path:match('^(.*)/[^/]+$')
	if dir and dir ~= '' then
		os.execute("mkdir -p '" .. dir:gsub("'", "'\\''") .. "'")
	end
	return true
end)

return M