clink_git_branch_argument.lua

-- This is a script to provide git branch autocompletion to clink
-- which can be used in windows cmd, conemu and cmder
-- 
-- Ctrl-Q in conemu to reload Clink Lua scripts
-- Clink match generators: https://github.com/mridgers/clink/blob/master/docs/clink.md#user-content-match-generators

-- based on:
-- https://gist.github.com/sweiss3/9858452
-- https://gist.github.com/bhank/a85113b06632fc52f053533f81c2da2d

-- copied from clink.lua
local git_argument_tree = {
    -- Porcelain and ancillary commands from git's man page.
    "add", "am", "archive", "bisect", "branch", "bundle", "checkout",
    "cherry-pick", "citool", "clean", "clone", "commit", "describe", "diff",
    "fetch", "format-patch", "gc", "grep", "gui", "init", "log", "merge", "mv",
    "notes", "pull", "push", "rebase", "reset", "revert", "rm", "shortlog",
    "show", "stash", "status", "submodule", "tag", "config", "fast-export",
    "fast-import", "filter-branch", "lost-found", "mergetool", "pack-refs",
    "prune", "reflog", "relink", "remote", "repack", "replace", "repo-config",
    "annotate", "blame", "cherry", "count-objects", "difftool", "fsck",
    "get-tar-commit-id", "help", "instaweb", "merge-tree", "rerere",
    "rev-parse", "show-branch", "verify-tag", "whatchanged"
}

parser = clink.arg.new_parser

function git_branches(word)
	local matches = {}

	for line in io.popen("git branch -a 2>nul"):lines() do
		local branch = line:match("[%* ] (.+)$")
		if branch then
			if branch:find(word, 1, true) then
				
				-- remove "remotes/" as we don't want to supply it for remote branches.
				local branch_cleanup = branch:gsub("remotes/", "")

				table.insert(matches, branch_cleanup)
			end
		end
	end
	return matches
end

function dir_match_generator_impl(text)
    -- Strip off any path components that may be on text.
    local prefix = ""
    local i = text:find("[\\/:][^\\/:]*$")
    if i then
        prefix = text:sub(1, i)
    end

    local include_dots = text:find("%.+$") ~= nil

    local matches = {}
    local mask = text.."*"

    -- Find matches.
    for _, dir in ipairs(clink.find_dirs(mask, true)) do
        local file = prefix..dir

        if include_dots or (dir ~= "." and dir ~= "..") then
            if clink.is_match(text, file) then
                table.insert(matches, prefix..dir)
            end
        end
    end

	for _, file in ipairs(clink.find_files(mask, true)) do
		if clink.is_match(text, file) then
			table.insert(matches, prefix..file)
		end
	end

    return matches
end

--------------------------------------------------------------------------------
local function dir_match_generator(word)
    local matches = dir_match_generator_impl(word)

    -- If there was no matches but text is a dir then use it as the single match.
    -- Otherwise tell readline that matches are files and it will do magic.
    if #matches == 0 then
        if clink.is_dir(rl_state.text) then
            table.insert(matches, rl_state.text)
        end
    else
        clink.matches_are_files()
    end

    return matches
end


-- create the parser:
-- first argument is from standard clink.lua
-- then provide 4 times the git_branches argument which should be enough

git_parser = clink.arg.new_parser()
git_parser:add_arguments(git_argument_tree, {git_branches, dir_match_generator}, {git_branches, dir_match_generator}, {git_branches, dir_match_generator})

clink.arg.register_parser("git", git_parser)