#!/opt/Lua51/bin/lua

-- Created by jiaqiang.ye@lnxall.com
-- Simple Git Repository Branch-Tag Management
-- 2025/07/28

local cjson      = require "cjson"
local invoker    = require "invoker"
local gfmt       = string.format

-- name of environment variable
local TAGMAN_CONF      = "TAGMAN_CONF"
local TAGMAN_CLEAN     = "LNXCLEAN"
local TAGMAN_MAXSIZE   = 0x100000
local FT_BUILD_SH      = "./build.bash"
-- table holding Git repository branch/tag information
local g_repinfo        = {}
local g_pathidx        = {}
-- directory path for `wlos_core
local g_topdir         = os.getenv("FTOPDIR")
-- configuration Lua script
local g_cfgfile        = nil

local function goodstr(s)
	if type(s) ~= "string" then return false end
	if string.len(s) == 0 then return false end
	return true
end

-- returns: FTOPDIR, Relative path for `build.bash
local function find_topdir(bpath)
	local dirstr, regdir = "directory", "^(.+)/+[^/]+$"
	if not bpath then
		bpath = invoker.getcwd()
	elseif invoker.statfile(bpath) ~= dirstr then
		bpath = string.match(bpath, regdir)
	end

	-- check again for initial path
	if invoker.statfile(bpath) ~= dirstr then
		if not goodstr(bpath) then bpath = "unknown" end
		io.stderr:write(gfmt("Error, not a directory: %s\n", bpath))
		io.stderr:flush()
		return nil, nil
	end

	-- relative path for `build.bash
	local reltab = 0
	while true do
		local bsh = gfmt("%s/build.bash", bpath)
		if invoker.statfile(bsh) == "regular" then break end

		reltab = reltab + 1
		bpath = string.match(bpath, regdir)
		if not goodstr(bpath) then break end
	end

	if goodstr(bpath) then
		if reltab == 0 then
			return bpath, FT_BUILD_SH
		end
		return bpath, gfmt("%s/build.bash", string.rep("../", reltab))
	end

	io.stderr:write("Error, FTOPDIR not found!\n")
	io.stderr:flush()
	return nil, nil
end

local function clean_checkout(path_g, btag)
	-- clean repository first
	local topdir, buildsh = find_topdir(nil)
	if topdir ~= g_topdir then
		io.stderr:write(gfmt("Error, invalid TOPDIR: %s <=> %s\n", topdir, g_topdir))
		io.stderr:flush()
		return false
	end

	local iflag = invoker.NOSTDIO
	if os.getenv('TAGMAN_VERBOSE') == "1" then iflag = 0 end
	if buildsh ~= FT_BUILD_SH then
		io.stdout:write(gfmt("INFO: cleaning repository: %s\n", path_g))
		io.stdout:flush()
		invoker.invoke(iflag, "bash", buildsh, "clean")
	end

	if not btag then return true end
	io.stdout:write(gfmt("INFO: updating repository: %s, branch/tag: %s\n", path_g, btag))
	io.stdout:flush()
	invoker.invoke(iflag, "git", "fetch", "--all", "--tags")

	io.stdout:write(gfmt("INFO: checking out branch/tag in %s: %s\n", path_g, btag))
	io.stdout:flush()
	if invoker.invoke(iflag, "git", "checkout", btag) == 0 then
		return true
	end
	return false
end

local function tagman_checkout()
	local repidx, oknum = 0, 0

	local dummystr, errmsg0, errmsg1 = "HELLO WOLRD", "to be committed", "not staged for commit"
	local inf0, inf1, inf2, wtclean = "On branch", "on any branch", "detached at", "working tree clean"
	local cmd_status = gfmt("set -o pipefail ; (echo '%s' && git status -uno) |& grep -e '%s' -e '%s' -e '%s' -e '%s' -e '%s' -e '%s' -e '%s'",
		dummystr, dummystr, inf0, inf1, inf2, wtclean, errmsg0, errmsg1)

	while true do
		repidx = repidx + 1
		local rinfo = g_repinfo[repidx]
		if not rinfo then break end

		-- Goto TOPDIR directory
		if invoker.chdir(g_topdir) ~= 0 then
			io.stderr:write(gfmt("Error, failed to go back to TOPDIR: %s\n", g_topdir))
			io.stderr:flush()
			return false
		end

		-- Then goto git repository
		if invoker.chdir(rinfo.path) ~= 0 then
			io.stderr:write(gfmt("Error, failed to goto directory: %s\n", rinfo.path))
			io.stderr:flush()
			return false
		end

		-- get repository status
		local okay, output = invoker.invoke(invoker.OUTPUT, "/bin/bash", "-c", cmd_status)
		if type(output) ~= "string" or string.len(output) == 0 then
			okay, output = -1, ""
			io.stderr:write(gfmt("Warning: empty output from repository: %s\n", rinfo.path))
			io.stderr:flush()
		end
		if string.find(output, wtclean, 1, true) then okay = 0 end
		if okay ~= 0 or
			string.find(output, errmsg0, 1, true) or
			string.find(output, errmsg1, 1, true) then
			io.stderr:write(gfmt("Error, working tree not clean: %s\n", rinfo.path))
			io.stderr:flush()
			return false
		end
		local res, git_status = true, output
		if rinfo.tag == TAGMAN_CLEAN then
			res = clean_checkout(rinfo.path)
		elseif rinfo.tag then
			okay, output = invoker.invoke(invoker.OUTPUT, "/bin/bash", "-c", "exec git log -1 2>&1")
			if okay ~= 0 then
				io.stderr:write(gfmt("Error, git log has failed in %s\n", rinfo.path))
				io.stderr:flush()
				return false
			end
			if type(output) ~= "string" then output = "" end
			local git_log = output
			okay, output = invoker.invoke(invoker.OUTPUT + invoker.TRIMEND, "/bin/bash", "-c",
				gfmt("exec git rev-list --max-count=1 '%s' 2>&1", rinfo.tag))
			if okay == 0 and goodstr(output) and string.find(git_log, output, 1, true) then
				io.stdout:write(gfmt("Repository '%s' already at TAG: %s\n", rinfo.path, rinfo.tag))
				io.stdout:flush()
			else
				res = clean_checkout(rinfo.path, rinfo.tag)
			end
		else
			if not string.find(git_status, gfmt("On branch %s\n", rinfo.branch), 1, true) then
				res = clean_checkout(rinfo.path, rinfo.branch)
			else
				io.stdout:write(gfmt("Repository '%s' already at branch: %s\n", rinfo.path, rinfo.branch))
				io.stdout:flush()
			end

			if res then
				io.stdout:write(gfmt("pull from branch: %s => %s\n", rinfo.path, rinfo.branch))
				io.stdout:flush()
				invoker.invoke(0, "git", "pull", "--rebase", "origin", rinfo.branch)
			end
		end

		if not res then
			io.stderr:write(gfmt("Error, failed to checkout branch/tag for '%s' => %s\n",
				rinfo.path, rinfo.tag or rinfo.branch))
			io.stderr:flush()
			return false
		end
		oknum = oknum + 1
	end

	return oknum
end

local function tagman_load()
	local cfgd = invoker.readfile(g_cfgfile, TAGMAN_MAXSIZE)
	if not cfgd then
		io.stderr:write(gfmt("Error, failed to read file: %s\n", g_cfgfile))
		io.stderr:flush()
		return false
	end

	local okay, jdat = pcall(cjson.decode, cfgd)
	cfgd = nil -- free memory early
	if not okay or type(jdat) ~= "table" then
		io.stderr:write(gfmt("Error, failed to decode as JSON: %s\n", g_cfgfile))
		io.stderr:flush()
		return false
	end

	local repos = jdat["repolist"]
	if type(repos) ~= "table" then
		io.stderr:write(gfmt("Error, repolist not found in %s\n", g_cfgfile))
		io.stderr:flush()
		return false
	end

	local repidx = 0
	while true do
		repidx = repidx + 1
		local rinfo = repos[repidx]
		if type(rinfo) ~= "table" then break end

		-- extract Git repo information
		local path_g, branch, tagv = rinfo['path'], rinfo['branch'], rinfo['tag']
		if not goodstr(path_g) then
			io.stderr:write(gfmt("Error, invalid git repository information at index: %d\n", repidx))
			io.stderr:flush()
			return false
		end

		local dotgit = gfmt("%s/.git", path_g)
		if invoker.statfile(path_g) ~= "directory" or
			invoker.statfile(dotgit) ~= "directory" then
			io.stderr:write(gfmt("Error, invalid git repository path: %s\n", path_g))
			io.stderr:flush()
			return false
		end

		if g_pathidx[path_g] then -- check for git duplication
			io.stderr:write(gfmt("Error, duplicated git repository: %s\n", path_g))
			io.stderr:flush()
			return false
		end

		if not goodstr(branch) then
			io.stderr:write(gfmt("Error, branch not specified for %s\n", path_g))
			io.stderr:flush()
			return false
		end
		if not goodstr(tagv) then tagv = nil end

		g_pathidx[path_g]  = repidx
		g_repinfo[repidx]   = {
			["path"]       = path_g,
			["branch"]     = branch,
			["tag"]        = tagv,
		}
	end

	return true
end

local function tagman_init(topdir, cfgjson)
	invoker.setenv("FTOPDIR", nil)
	invoker.setenv("LANGUAGE", nil)
	invoker.setenv("LANG", "en_US.UTF-8")
	-- transform relative path for `tagman to full path:
	topdir = invoker.realpath(topdir)
	if not goodstr(topdir) then
		io.stderr:write("Error, failed to determine script path.\n")
		io.stderr:flush()
		return false
	end

	-- split path until we have found `build.bash:
	topdir = find_topdir(topdir)
	if not goodstr(topdir) then return false end
	if goodstr(g_topdir) then
		if g_topdir ~= topdir then
			io.stderr:write(gfmt("Warning, build.bash found more than once: %s <=> %s\n",
				g_topdir, topdir))
			io.stderr:flush()
		end
	else -- `g_topdir is nil, set as `topdir:
		g_topdir = topdir
	end
	io.stdout:write(gfmt("Non-openwrt TOPDIR: %s\n", topdir))
	io.stdout:flush()

	-- determine configuration file
	local cfgfile, cfgpath = os.getenv(TAGMAN_CONF), nil
	invoker.setenv(TAGMAN_CONF, nil)
	if not goodstr(cfgfile) then
		if not goodstr(cfgjson) then
			io.stderr:write("Error, environment variable not found: `TAGMAN_CONF\n")
			io.stderr:flush()
			return false
		end
		cfgfile = cfgjson
	end

	if invoker.statfile(cfgfile) == "regular" then
		cfgpath = invoker.realpath(cfgfile)
	else
		cfgpath = gfmt("%s/tagman/%s", topdir, cfgfile)
	end
	-- make sure that the configuration file exists
	local ftype, fsize = invoker.statfile(cfgpath)
	if ftype ~= "regular" then
		io.stderr:write(gfmt("Error, tagman config file not found: %s\n", cfgfile))
		io.stderr:flush()
		return false
	end
	if fsize == 0 or fsize > TAGMAN_MAXSIZE then
		io.stderr:write(gfmt("Error, invalid file size: %s\n", cfgfile))
		io.stderr:flush()
		return false
	end
	g_cfgfile = cfgpath
	io.stdout:write(gfmt("INFO: using branch/tag-config file: %s\n", cfgpath))
	io.stdout:flush()

	-- Go to TOPDIR
	if invoker.chdir(topdir) ~= 0 then
		io.stdout:write(gfmt("Error, Failed to goto top-directory: %s\n", topdir))
		io.stdout:flush()
		return false
	end
	-- load the configuration file
	return tagman_load()
end

if not tagman_init(arg[0], arg[1]) then
	os.exit(1)
end
local numok = tagman_checkout()
if numok then
	io.stdout:write(gfmt("Number of repositories processed: %d\n", numok))
	io.stdout:flush()
	os.exit(0)
end
os.exit(2)