--[[

File l3build-arguments.lua Copyright (C) 2018 The LaTeX3 Project

It may be distributed and/or modified under the conditions of the
LaTeX Project Public License (LPPL), either version 1.3c of this
license or (at your option) any later version.  The latest version
of this license is in the file

   http://www.latex-project.org/lppl.txt

This file is part of the "l3build bundle" (The Work in LPPL)
and all files in that bundle must be distributed together.

-----------------------------------------------------------------------

The development version of the bundle can be found at

   https://github.com/latex3/l3build

for those people who are interested.

--]]

local exit             = os.exit
local stderr           = io.stderr

local find             = string.find
local gmatch           = string.gmatch
local match            = string.match
local sub              = string.sub

local insert           = table.insert

-- Parse command line options

option_list =
  {
    config =
      {
        desc  = "Sets the config(s) used for running tests",
        short = "c",
        type  = "table"
      },
    date =
      {
        desc  = "Sets the date to insert into sources",
        type  = "string"
      },
    ["dry-run"] =
      {
        desc = "Dry run for install",
        type = "boolean"
      },
    engine =
      {
        desc  = "Sets the engine(s) to use for running test",
        short = "e",
        type  = "table"
      },
    epoch =
      {
        desc  = "Sets the epoch for tests and typesetting",
        type  = "string"
      },
    first =
      {
        desc  = "Name of first test to run",
        type  = "string"
      },
    force =
      {
        desc  = "Force tests to run if engine is not set up",
        short = "f",
        type  = "boolean"
      },
    ["halt-on-error"] =
      {
        desc  = "Stops running tests after the first failure",
        short = "H",
        type  = "boolean"
      },
    help =
      {
        short = "h",
        type  = "boolean"
      },
    pdf =
      {
        desc  = "Check/save PDF files",
        short = "p",
        type  = "boolean"
      },
    quiet =
      {
        desc  = "Suppresses TeX output when unpacking",
        short = "q",
        type  = "boolean"
      },
    last =
      {
        desc  = "Name of last test to run",
        type  = "string"
      },
    rerun =
      {
        desc  = "Skip setup: simply rerun tests",
        type  = "boolean"
      },
    shuffle =
      {
        desc  = "Shuffle order of tests",
        type  = "boolean"
      },
    texmfhome =
      {
        desc = "Location of user texmf tree",
        type = "string"
      }
  }

-- This is done as a function (rather than do ... end) as it allows early
-- termination (break)
local function argparse()
  local result = { }
  local names  = { }
  local long_options =  { }
  local short_options = { }
  -- Turn long/short options into two lookup tables
  for k,v in pairs(option_list) do
    if v["short"] then
      short_options[v["short"]] = k
    end
    long_options[k] = k
  end
  local args = args
  -- arg[1] is a special case: must be a command or "-h"/"--help"
  -- Deal with this by assuming help and storing only apparently-valid
  -- input
  local a = arg[1]
  result["target"] = "help"
  if a then
    -- No options are allowed in position 1, so filter those out
    if a == "--version" then
      result["target"] = "version"
    elseif not match(a, "^%-") then
      result["target"] = a
    end
  end
  -- Stop here if help or version is required
  if result["target"] == "help" or result["target"] == "version" then
    return result
  end
  -- An auxiliary to grab all file names into a table
  local function remainder(num)
    local names = { }
    for i = num, #arg do
      insert(names, arg[i])
    end
    return names
  end
  -- Examine all other arguments
  -- Use a while loop rather than for as this makes it easier
  -- to grab arg for optionals where appropriate
  local i = 2
  while i <= #arg do
    local a = arg[i]
    -- Terminate search for options
    if a == "--" then
      names = remainder(i + 1)
      break
    end
    -- Look for optionals
    local opt
    local optarg
    local opts
    -- Look for and option and get it into a variable
    if match(a, "^%-") then
      if match(a, "^%-%-") then
        opts = long_options
        local pos = find(a, "=", 1, true)
        if pos then
          opt    = sub(a, 3, pos - 1)
          optarg = sub(a, pos + 1)
        else
          opt = sub(a, 3)
        end
      else
        opts = short_options
        opt  = sub(a, 2, 2)
        -- Only set optarg if it is there
        if #a > 2 then
          optarg = sub(a, 3)
        end
      end
      -- Now check that the option is valid and sort out the argument
      -- if required
      local optname = opts[opt]
      if optname then
        -- Tidy up arguments
        if option_list[optname]["type"] == "boolean" then
          if optarg then
            local opt = "-" .. (match(a, "^%-%-") and "-" or "") .. opt
            stderr:write("Value not allowed for option " .. opt .."\n")
            return {"help"}
          end
        else
         if not optarg then
          optarg = arg[i + 1]
          if not optarg then
            stderr:write("Missing value for option " .. a .."\n")
            return {"help"}
          end
          i = i + 1
         end
        end
      else
        stderr:write("Unknown option " .. a .."\n")
        return {"help"}
      end
      -- Store the result
      if optarg then
        if option_list[optname]["type"] == "string" then
          result[optname] = optarg
        else
          local opts = result[optname] or { }
          for hit in gmatch(optarg, "([^,%s]+)") do
            insert(opts, hit)
          end
          result[optname] = opts
        end
      else
        result[optname] = true
      end
      i = i + 1
    end
    if not opt then
      names = remainder(i)
      break
    end
  end
  if next(names) then
   result["names"] = names
  end
  return result
end

options = argparse()

-- Sanity check
function check_engines()
  if options["engine"] and not options["force"] then
     -- Make a lookup table
     local t = { }
    for _, engine in pairs(checkengines) do
      t[engine] = true
    end
    for _, engine in pairs(options["engine"]) do
      if not t[engine] then
        print("\n! Error: Engine \"" .. engine .. "\" not set up for testing!")
        print("\n  Valid values are:")
        for _, engine in ipairs(checkengines) do
          print("  - " .. engine)
        end
        print("")
        exit(1)
      end
    end
  end
end