-- Pure-Lua structural linter over services/. Validates that every service
-- directory has the files its `type` requires, that every
-- dependencies.d/contents.d entry names a real sibling service, and that
-- producer-for/consumer-for pairs are mutually consistent.
--
-- No lfs/posix available, so directory listing shells out to `dir /b` on
-- Windows or `ls -1a` on Unix.
--
-- Usage: lua55 tools/lint.lua

local function is_windows()
	return package.config:sub(1, 1) == "\\"
end

local function list_dir(path)
	local cmd
	if is_windows() then
		cmd = 'dir /b "' .. path:gsub("/", "\\") .. '" 2>nul'
	else
		cmd = 'ls -1a "' .. path .. '" 2>/dev/null'
	end
	local entries = {}
	local p = io.popen(cmd)
	if not p then
		return entries
	end
	for line in p:lines() do
		if line ~= "." and line ~= ".." and line ~= "" then
			table.insert(entries, line)
		end
	end
	p:close()
	return entries
end

local function read_file(path)
	local f = io.open(path, "r")
	if not f then
		return nil
	end
	local content = f:read("*a")
	f:close()
	return content
end

local function trim(s)
	return s:match("^%s*(.-)%s*$")
end

local script_dir = arg[0]:match("^(.*)[/\\][^/\\]*$") or "."
local repo_root = script_dir .. "/.."
local services_dir = repo_root .. "/services"

local errors = {}
local function fail(fmt, ...)
	table.insert(errors, string.format(fmt, ...))
end

local names = list_dir(services_dir)
local svc_type = {}

for _, name in ipairs(names) do
	local dir = services_dir .. "/" .. name
	local t = read_file(dir .. "/type")
	if not t then
		fail("%s: missing 'type' file", name)
	else
		t = trim(t)
		svc_type[name] = t
		if t ~= "oneshot" and t ~= "longrun" and t ~= "bundle" then
			fail("%s: type must be oneshot|longrun|bundle, got %q", name, t)
		elseif t == "oneshot" and not read_file(dir .. "/up") then
			fail("%s: oneshot missing 'up'", name)
		elseif t == "longrun" and not read_file(dir .. "/run") then
			fail("%s: longrun missing 'run'", name)
		elseif t == "bundle" and #list_dir(dir .. "/contents.d") == 0 then
			fail("%s: bundle has empty/missing contents.d", name)
		end
	end
end

local function exists(name)
	return svc_type[name] ~= nil
end

for _, name in ipairs(names) do
	local dir = services_dir .. "/" .. name

	for _, dep in ipairs(list_dir(dir .. "/dependencies.d")) do
		if not exists(dep) then
			fail("%s: dependencies.d references unknown service %q", name, dep)
		end
	end

	for _, member in ipairs(list_dir(dir .. "/contents.d")) do
		if not exists(member) then
			fail("%s: contents.d references unknown service %q", name, member)
		end
	end

	local producer = read_file(dir .. "/producer-for")
	if producer then
		producer = trim(producer)
		if not exists(producer) then
			fail("%s: producer-for references unknown service %q", name, producer)
		else
			local consumer = read_file(services_dir .. "/" .. producer .. "/consumer-for")
			if not consumer or trim(consumer) ~= name then
				fail("%s: producer-for %s but %s's consumer-for does not point back", name, producer, producer)
			end
			if not read_file(services_dir .. "/" .. producer .. "/pipeline-name") then
				fail("%s: logger %s missing pipeline-name", name, producer)
			end
		end
	end

	local nfd = read_file(dir .. "/notification-fd")
	if nfd and not trim(nfd):match("^%d+$") then
		fail("%s: notification-fd must be a bare integer, got %q", name, trim(nfd))
	end
end

if #errors > 0 then
	for _, e in ipairs(errors) do
		io.stderr:write("LINT: " .. e .. "\n")
	end
	io.stderr:write(string.format("%d lint error(s)\n", #errors))
	os.exit(1)
end

print(string.format("lint OK: %d service directories checked", #names))