#!  /usr/bin/lua
-- $NetBSD: check-expect.lua,v 1.3 2022/04/15 09:33:20 rillig Exp $

--[[

usage: lua ./check-expect.lua *.mk

Check that each text from an '# expect: ...' comment in the .mk source files
occurs in the corresponding .exp file, in the same order as in the .mk file.

Check that each text from an '# expect[+-]offset: ...' comment in the .mk
source files occurs in the corresponding .exp file and refers back to the
correct line in the .mk file.

]]


local had_errors = false
---@param fmt string
function print_error(fmt, ...)
  print(fmt:format(...))
  had_errors = true
end


---@return nil | string[]
local function load_lines(fname)
  local lines = {}

  local f = io.open(fname, "r")
  if f == nil then return nil end

  for line in f:lines() do
    table.insert(lines, line)
  end
  f:close()

  return lines
end


---@param exp_lines string[]
local function collect_lineno_diagnostics(exp_lines)
  ---@type table<string, string[]>
  local by_location = {}

  for _, line in ipairs(exp_lines) do
    ---@type string | nil, string, string
    local l_fname, l_lineno, l_msg =
      line:match("^make: \"([^\"]+)\" line (%d+): (.*)")
    if l_fname ~= nil then
      local location = ("%s:%d"):format(l_fname, l_lineno)
      if by_location[location] == nil then
        by_location[location] = {}
      end
      table.insert(by_location[location], l_msg)
    end
  end

  return by_location
end


local function check_mk(mk_fname)
  local exp_fname = mk_fname:gsub("%.mk$", ".exp")
  local mk_lines = load_lines(mk_fname)
  local exp_lines = load_lines(exp_fname)
  if exp_lines == nil then return end
  local by_location = collect_lineno_diagnostics(exp_lines)
  local prev_expect_line = 0

  for mk_lineno, mk_line in ipairs(mk_lines) do
    for text in mk_line:gmatch("#%s*expect:%s*(.*)") do
      local i = prev_expect_line
      -- As of 2022-04-15, some lines in the .exp files contain trailing
      -- whitespace.  If possible, this should be avoided by rewriting the
      -- debug logging.  When done, the gsub can be removed.
      -- See deptgt-phony.exp lines 14 and 15.
      while i < #exp_lines and text ~= exp_lines[i + 1]:gsub("%s*$", "") do
        i = i + 1
      end
      if i < #exp_lines then
        prev_expect_line = i + 1
      else
        print_error("error: %s:%d: '%s:%d+' must contain '%s'",
          mk_fname, mk_lineno, exp_fname, prev_expect_line + 1, text)
      end
    end
    if mk_line:match("^#%s*expect%-reset$") then
      prev_expect_line = 0
    end

    ---@param text string
    for offset, text in mk_line:gmatch("#%s*expect([+%-]%d+):%s*(.*)") do
      local location = ("%s:%d"):format(mk_fname, mk_lineno + tonumber(offset))

      local found = false
      if by_location[location] ~= nil then
        for i, message in ipairs(by_location[location]) do
          if message ~= "" and message:find(text, 1, true) then
            by_location[location][i] = ""
            found = true
            break
          end
        end
      end

      if not found then
        print_error("error: %s:%d: %s must contain '%s'",
          mk_fname, mk_lineno, exp_fname, text)
      end
    end
  end
end

for _, fname in ipairs(arg) do
  check_mk(fname)
end
os.exit(not had_errors)