module(...,package.seeall)

local log = logging.new("mkutils")

local make4ht = require("make4ht-lib")
local mkparams = require("mkparams")
local indexing = require("make4ht-indexing")
--template engine
function interp(s, tab)
  local tab = tab or {}
  return (s:gsub('($%b{})', function(w) return tab[w:sub(3, -2)] or w end))
end
--print( interp("${name} is ${value}", {name = "foo", value = "bar"}) )

function addProperty(s,prop)
  if prop ~=nil then
    return s .." "..prop
  else
    return s
  end
end
getmetatable("").__mod = interp
getmetatable("").__add = addProperty 

--print( "${name} is ${value}" % {name = "foo", value = "bar"} )
-- Outputs "foo is bar"

function is_url(path)
  return path:match("^%a+://")
end


-- merge two tables recursively
function merge(t1, t2)
  for k, v in pairs(t2) do
    if (type(v) == "table") and (type(t1[k] or false) == "table") then
      merge(t1[k], t2[k])
    else
      t1[k] = v
    end
  end
  return t1
end

function string:split(sep)
  local sep, fields = sep or ":", {}
  local pattern = string.format("([^%s]+)", sep)
  self:gsub(pattern, function(c) fields[#fields+1] = c end)
  return fields
end

function remove_extension(path)
  local found, len, remainder = string.find(path, "^(.*)%.[^%.]*$")
  if found then
    return remainder
  else
    return path
  end
end

-- 
-- check if file exists
function file_exists(file)
  local f = io.open(file, "rb")
  if f then f:close() end
  return f ~= nil
end

-- check if Lua module exists
-- source: https://stackoverflow.com/a/15434737/2467963
function isModuleAvailable(name)
  if package.loaded[name] then
    return true
  else
    for _, searcher in ipairs(package.searchers or package.loaders) do
      local loader = searcher(name)
      if type(loader) == 'function' then
        package.preload[name] = loader
        return true
      end
    end
    return false
  end
end


-- searching for converted images
function parse_lg(filename, builddir)
  log:info("Parse LG")
  local dir = builddir~="" and builddir .. "/" or ""
  local outputimages,outputfiles,status={},{},nil
  local fonts, used_fonts = {},{}
  if not file_exists(filename) then
    log:warning("Cannot read log file: "..filename)
  else
    local usedfiles={}
    for line in io.lines(filename) do
      --- needs --- pokus.idv[1] ==> pokus0x.png --- 
      -- line:gsub("needs --- (.+?)[([0-9]+) ==> ([%a%d%p%.%-%_]*)",function(name,page,k) table.insert(outputimages,k)end)
      line:gsub("needs %-%-%- (.+)%[([0-9]+)%] ==> (.*) %-%-%-",
      function(file,page,output) 
        local rec = {
          source=file,
          page=page,
          output=dir..output
        }
        table.insert(outputimages,rec)
      end
      )
      line:gsub("File: (.*)",  function(x)
        local k = dir .. x
        if not file_exists(k) then
          k = x
        end
        if not usedfiles[k] then
          table.insert(outputfiles,k)
          usedfiles[k] = true
        end
      end)
      line:gsub("htfcss: ([^%s]+)(.*)",function(k,r)
        local fields = {}
        r:gsub("[%s]*([^%:]+):[%s]*([^;]+);",function(c,v)
          fields[c] = v
        end)
        fonts[k] = fields
      end)

      line:gsub('Font("([^"]+)","([%d]+)","([%d]+)","([%d]+)"',function(n,s1,s2,s3)
        table.insert(used_fonts,{n,s1,s2,s3})
      end)

    end
    status=true
  end
  return {files = outputfiles, images = outputimages},status
end


-- 
local cp_func = os.type == "unix" and "cp" or "copy"
-- maybe it would be better to actually move the files
-- in reality it isn't.
-- local cp_func = os.type == "unix" and "mv" or "move"
function cp(src,dest)
  if is_url(src) then
    log.info(src .. " is a URL, will leave as is")
    return
  end
  if not file_exists(src) then
    -- try to find file using kpse library if it cannot be found
    src = kpse.find_file(src) or src
  end
  local command = string.format('%s "%s" "%s"', cp_func, src, dest)
  if cp_func == "copy" then command = command:gsub("/",'\\') end
  log:info("Copy: "..command)
  if not file_exists(src) then
    log:error("File " .. src .. " doesn't exist")
  end
  os.execute(command)
end

function mv(src, dest)
  local mv_func = os.type == "unix" and "mv " or "move "
  local command = string.format('%s "%s" "%s"', mv_func, src, dest)
  -- fix windows paths
  if mv_func == "move" then command = command:gsub("/",'\\') end
  log:info("Move: ".. command)
  os.execute(command)
end

function delete_dir(path)
  local cmd = os.type == "unix" and "rm -rd " or "rd /s/q "
  os.execute(cmd .. path)
end

local used_dir = {}

function prepare_path(path)
  --local dirs = path:split("/")
  local dirs = {}
  if path:match("^/") then dirs = {""}
  elseif path:match("^~") then
    local home = os.getenv "HOME"
    dirs = home:split "/"
    path = path:gsub("^~/","")
    table.insert(dirs,1,"")
  end
  if path:match("/$")then path = path .. " " end
  for _,d in pairs(path:split "/") do
    table.insert(dirs,d)
  end
  table.remove(dirs,#dirs)
  return dirs,table.concat(dirs,"/")
end

-- Find which part of path already exists
-- and which directories have to be created
function find_directories(dirs, pos)
  local pos = pos or #dirs
  -- we tried whole path and no dir exist
  if pos < 1 then return dirs end
  local path = ""
  -- in the case of unix absolute path, empty string is inserted in dirs
  if pos == 1 and dirs[pos] == "" then
    path = "/"
  else
    path = table.concat(dirs,"/", 1,pos) .. "/"
  end
  if not lfs.chdir(path)  then -- recursion until we succesfully changed dir
    -- or there are no elements in the dir table
    return find_directories(dirs,pos - 1)
  elseif pos ~= #dirs then -- if we succesfully changed dir
    -- and we have dirs to create
    local p = {}
    for i = pos+1, #dirs do
      table.insert(p, dirs[i])
    end
    return p
  else  -- whole path exists
    return {}
  end
end

function mkdirectories(dirs)
  if type(dirs) ~="table" then
    return false, "mkdirectories: dirs is not table"
  end
  local path = ""
  for _,d in ipairs(dirs) do
    path = path .. d .. "/"
    local stat,msg = lfs.mkdir(path)
    if not stat then return false, "makedirectories error: "..msg end
  end
  return true
end

function make_path(path)
  -- we must create the build dir if it doesn't exist
  local cwd = lfs.currentdir()
  -- add dummy /foo dir. it won't be created, but without that, the top-level dir wouldn't be created
  local parts = mkutils.prepare_path(path .. "/foo")
  local to_create = mkutils.find_directories(parts)
  mkutils.mkdirectories(to_create)
  -- change back to the original dir
  lfs.chdir(cwd)
end

function file_in_builddir(filename, par)
  if par.builddir and par.builddir ~= "" then
    local newname = par.builddir .. "/" .. filename
    return newname
  end
  return filename
end

function copy_filter(src,dest, filter)
  local src_f=io.open(src,"rb")
  local dst_f=io.open(dest,"w")
  local contents = src_f:read("*all")
  local filter = filter or function(s) return s end
  src_f:close()
  dst_f:write(filter(contents))
  dst_f:close()
end



function copy(filename,outfilename)
  local currdir = lfs.currentdir()
  if filename == outfilename then return true end
  local parts, path = prepare_path(outfilename)
  if not used_dir[path] then 
    local to_create, msg = find_directories(parts)
    if not to_create then
      log:warning(msg)
      return false
    end
    used_dir[path] = true
    local stat, msg = mkdirectories(to_create)
    if not stat then log:warning(msg) end
  end
  lfs.chdir(currdir)
  cp(filename, path)
  return true
end

function execute(command)
  local f = io.popen(command, "r")
  local output = f:read("*all")
  -- rc will contain return codes of the executed command
  local rc =  {f:close()}
  -- the status code is on the third position 
  -- https://stackoverflow.com/a/14031974/2467963
  local status = rc[3]
  -- print the command line output only when requested through
  -- log  level
  log:output(output)
  return status, output
end

-- find the zip command
function find_zip()
  if io.popen("zip -v","r"):close() then
    return "zip"
  elseif io.popen("miktex-zip -v","r"):close() then
    return "miktex-zip"
  end
  -- we cannot find the zip command
  return "zip"
end

-- Config loading
local function run(untrusted_code, env)
  if untrusted_code:byte(1) == 27 then return nil, "binary bytecode prohibited" end
  local untrusted_function = nil
  untrusted_function, message = load(untrusted_code, nil, "t",env)
  if not untrusted_function then return nil, message end
  if not setfenv then setfenv = function(a,b) return true end end
  setfenv(untrusted_function, env)
  return pcall(untrusted_function)
end

local main_settings = {}
main_settings.fonts = {}
-- use global environment in the build file
-- it used to be sandboxed, but it proved not to be useful at all
local env = _G ---{}

-- explicitly enale some functions and modules in the sandbox
-- Function declarations:
env.pairs  = pairs
env.ipairs = ipairs
env.print  = print
env.split  = split
env.string = string
env.table  = table
env.copy   = copy
env.tonumber = tonumber
env.tostring = tostring
env.mkdirectories = mkdirectories
env.require = require
env.texio  = texio
env.type   = type
env.lfs    = lfs
env.os     = os
env.io     = io
env.math   = math
env.unicode = unicode
env.logging = logging


-- it is necessary to use the settings table
-- set in the Make environment by mkutils
function env.set_settings(par)
  local settings = env.settings
  for k,v in pairs(par) do
    settings[k] = v
  end
end

-- Add a value to the current settings
function env.settings_add(par)
  local settings = env.settings
  for k,v in pairs(par) do
    local oldval = settings[k] or ""
    settings[k] = oldval .. v
  end
end

function env.get_filter_settings(name)
  local settings = env.settings
  -- local settings = self.params
  local filters = settings.filter or {}
  local filter_options = filters[name] or {}
  return filter_options
end

function env.filter_settings(name)
  -- local settings = Make.params
  local settings = env.settings
  local filters = settings.filter or {}
  local filter_options = filters[name] or {}
  return function(par)
    filters[name] = merge(filter_options, par)
    settings.filter = filters
  end
end
env.Font   = function(s)
  local font_name = s["name"]
  if not font_name then return nil, "Cannot find font name" end
  env.settings.fonts[font_name] = s
end

env.Make   = make4ht.Make
env.Make.params = env.settings
env.Make:add("test","test the variables:  ${tex4ht_sty_par} ${htlatex} ${input} ${config}")

local htlatex = require "make4ht-htlatex"
env.Make:add("htlatex", htlatex.htlatex
,{correct_exit=0})
env.Make:add("httex", htlatex.httex, {
  htlatex = "etex",
  correct_exit=0
})

env.Make:add("latexmk", function(par)
  local settings = get_filter_settings "htlatex" or {}
  par.interaction = par.interaction or settings.interaction or "batchmode"
  local command = Make.latex_command 
  -- add " %O " after the engine name. it should be filled by latexmk
  command = command:gsub("%s", " %%O ", 1)
  par.expanded = command % par
  -- quotes in latex_command must be escaped, they cause Latexmk error
  par.expanded = par.expanded:gsub('"', '\\"')
  local newcommand = 'latexmk  -pdf- -ps- -auxdir=${builddir} -outdir=${builddir} -latex="${expanded}" -dvi -jobname=${input} ${tex_file}' % par
  log:info("LaTeX call: " .. newcommand)
  os.execute(newcommand)
  return Make.testlogfile(par)
end, {correct_exit= 0})



-- env.Make:add("tex4ht","tex4ht ${tex4ht_par} \"${input}.${dvi}\"", nil, 1)
env.Make:add("tex4ht",function(par)
  -- detect if svg output is used
  -- if yes, we need to pass the -g.svg option to tex4ht command
  -- to support svg images for character pictures
  local logfile = mkutils.file_in_builddir(par.input .. ".log", par)
  if file_exists(logfile) then
    for line in io.lines(logfile) do
      local options = line:match("TeX4ht package options:(.+)")
      if options then
        log:info(options)
        if options:match("svg") then
          par.tex4ht_par = (par.tex4ht_par or "") .. " -g.svg"
        end
        break
      end
    end
  end
  local cwd = lfs.currentdir()
  if par.builddir~="" then
      lfs.chdir(par.builddir)
  end
  local command = "tex4ht ${tex4ht_par} \"${input}.${dvi}\"" % par
  log:info("executing: " .. command)
  local status, output = execute(command)
  lfs.chdir(cwd)
  return status, output
end
, nil, 1)
env.Make:add("t4ht", function(par)
    par.ext = "dvi"
    local cwd = lfs.currentdir()
    if par.builddir ~= "" then
        lfs.chdir(par.builddir)
    end
    local command = "t4ht ${t4ht_par} \"${input}.${ext}\"" % par
    log:info("executing: " .. command)
    execute(command)
    lfs.chdir(cwd)
end
)

env.Make:add("clean", function(par)
  -- remove all functions that process produced files
  -- we will provide only one function, that remove all of them
  Make.matches = {}
  local main_name = mkutils.file_in_builddir( par.input, par)
  local remove_file = function(filename)
    if file_exists(filename) then
      log:info("removing file: " .. filename)
      os.remove(filename)
    end
  end
  -- try to find if the last converted file was in the ODT format
  local lg_name =  main_name .. ".lg"
  local lg_file = parse_lg(lg_name, par.builddir)
  local is_odt = false
  if lg_file and lg_file.files then
    for _, x in ipairs(lg_file.files) do
      is_odt = x:match("odt$") or is_odt
    end
  end
  if is_odt then
    Make:match("4om$",function(filename)
      -- math temporary file
      local to_remove = filename:gsub("4om$", "tmp")
      remove_file(to_remove)
      return false
    end)
    Make:match("4og$", remove_file)
  end
  Make:match("tmp$", function()
    -- remove temporary and auxilary files
    for _,ext in ipairs {"aux", "xref", "tmp", "4tc", "4ct", "idv", "lg","dvi", "log", "ncx", "idx", "ind"} do
      remove_file(main_name .. "." .. ext)
    end
  end)
  Make:match(".*", function(filename, par)
    -- remove only files that start with the input file basename
    -- this should prevent removing of images. this also means that
    -- images shouldn't be names as <filename>-hello.png for example
    if filename:find(main_name, 1,true) then
      -- log:info("Matched file", filename)
      remove_file(filename)
    end
  end)

end)

-- enable extension in the config file
-- the following two functions must be here and not in make4ht-lib.lua
-- because of the access to env.settings
env.Make.enable_extension = function(self,name)
  table.insert(env.settings.extensions, {type="+", name=name})
end

-- disable extension in the config file
env.Make.disable_extension = function(self,name)
  table.insert(env.settings.extensions, {type="-", name=name})
end

function load_config(settings, config_name)
  local settings = settings or main_settings
  -- the extensions requested from the command line should take precedence over
  -- extensions enabled in the config file
  local saved_extensions = settings.extensions
  settings.extensions = {}
  env.settings = settings
  env.mode = settings.mode
  if config_name and not file_exists(config_name) then
    config_name = kpse.find_file(config_name, 'texmfscripts') or config_name
  end
  local f = io.open(config_name,"r")
  if not f then 
    log:info("Cannot open config file", config_name)
    return  env
  end
  log:info("Using build file", config_name)
  local code = f:read("*all")
  local fn, msg = run(code,env)
  if not fn then log:warning(msg) end
  assert(fn)
  -- reload extensions from command line arguments for the "format" parameter
  for _,v in ipairs(saved_extensions) do
    table.insert(settings.extensions, v)
  end
  return env
end

env.Make:add("xindy", function(par)
  local xindylog = logging.new "xindy"
  local settings = get_filter_settings "xindy" or {}
  par.encoding  = settings.encoding or  par.encoding or "utf8"
  par.language = settings.language or par.language or "english"
  local modules = settings.modules or par.modules or {}
  local t = {}
  for k,v in ipairs(modules) do
    xindylog:debug("Loading module: " ..v)
    t[#t+1] = "-M ".. v
  end
  par.moduleopt = table.concat(t, " ")
  return  indexing.run_indexing_command("texindy -L ${language} -C ${encoding} ${moduleopt} -o ${indfile} ${newidxfile}", par)
end, {})

env.Make:add("makeindex", function(par)
  local makeindxcall = "makeindex ${options} -t ${ilgfile} -o ${indfile} ${newidxfile}"
  local settings = get_filter_settings "makeindex" or {}
  par.options = settings.options or par.options  or ""
  par.ilgfile = par.input .. ".ilg" 
  local status = indexing.run_indexing_command(makeindxcall, par)
  return status
end, {})

env.Make:add("xindex", function(par)
  local xindex_call = "xindex -l ${language} ${options} -o ${indfile} ${newidxfile}"
  local settings = get_filter_settings "xindex" or {}
  par.options = settings.options or par.options  or ""
  par.language = settings.language or par.language or "en"
  local status = indexing.run_indexing_command(xindex_call, par)
  return status
end, {})



local function find_lua_file(name)
  local extension_path = name:gsub("%.", "/") .. ".lua"
  return kpse.find_file(extension_path, "lua")
end

-- for the BibLaTeX support
env.Make:add("biber", "biber ${input}")
env.Make:add("bibtex", "bibtex ${input}")
env.Make:add("pythontex", "pythontex ${input}")

--- load the output format plugins
function load_output_format(format_name)
  local format_library =  "make4ht.formats.make4ht-"..format_name
  local is_format_file = find_lua_file(format_library)
  if is_format_file then 
    local format = assert(require(format_library))
    if format then
      format.prepare_extensions = format.prepare_extensions or function(extensions) return extensions end
      format.modify_build = format.modify_build or function(make) return make end
    end
    return format
  end
end

--- Execute the prepare_parameters function in list of extensions
function extensions_prepare_parameters(extensions, parameters)
  for _, ext in ipairs(extensions) do
    -- execute the extension only if it contains prepare_parameters function
    local fn = ext.prepare_parameters
    if fn then
      parameters = fn(parameters)
    end
  end
  return parameters
end

--- Modify the build sequence using extensions
-- @param extensions list of extensions 
-- @make  Make object
function extensions_modify_build(extensions, make)
  for _, ext in ipairs(extensions) do
    local fn = ext.modify_build
    if fn then
      make = fn(make)
    end
  end
  return make
end


--- load one extension
-- @param name  extension name
-- @param format current output format
function load_extension(name,format)
  -- first test if the extension exists
  local extension_library = "make4ht.extensions.make4ht-ext-" .. name
  local is_extension_file = find_lua_file(extension_library)
  -- don't try to load the extension if it doesn't exist
  if not is_extension_file then return nil, "cannot fint extension " .. name  end
  local extension = nil
  local local_extension_path = package.searchpath(extension_library, package.path)
  if local_extension_path then
      extension = dofile(local_extension_path)
  else
      extension = require("make4ht.extensions.make4ht-ext-".. name)
  end
  -- extensions can test if the current output format is supported
  local test = extension.test
  if test then
    if test(format) then 
      return extension
    end
    -- if the test fail return nil
    return nil, "extension " .. name .. " is not supported in the " .. format .. " format"
  end
  -- if the extension doesn't provide the test function, we will assume that
  -- it supports every output format
  return extension
end

--- load extensions
-- @param extensions table created by mkparams.get_format_extensions function
-- @param format  output type format. extensions may support only certain file
-- formats
function load_extensions(extensions, format)
  local module_names = {}
  local extension_table = {}
  local extension_sequence = {}
  -- process the extension table. it contains type field, which can enable or
  -- diable the extension
  for _, v in ipairs(extensions) do
    local enable = v.type == "+" and true or nil
    -- load extenisons in a correct order
    -- don't load extensions multiple times
    if enable and not module_names[v.name] then
      table.insert(extension_sequence, v.name)
    end
    -- the last extension request can disable it
    module_names[v.name] = enable
  end
  for _, name in ipairs(extension_sequence) do
    -- the extension can be inserted into the extension_sequence, but disabled
    -- later.
    if module_names[name] == true then
      local extension, msg= load_extension(name,format)
      if extension then
        log:info("Load extension", name)
        table.insert(extension_table, extension)
      else
        log:warning("Cannot load extension: ".. name)
        log:warning(msg)
      end
    end
  end
  return extension_table
end

--- add new extensions to a list of loaded extensions
-- @param added  string with extensions to be added in the form +ext1+ext2
function add_extensions(added, extensions)
  local _, newextensions = mkparams.get_format_extensions("dummyfmt" .. added)
  -- insert new extension at the beginning, in order to support disabling using
  -- the -f option
  for _, x in ipairs(extensions or {}) do table.insert(newextensions, x) end
  return newextensions
end

-- I don't know if this is clean, but settings functions won't be available
-- for filters and extensions otherwise
for k,v in pairs(env) do _G[k] = v end
