------ generating HTML output ---------
-- Although this can be generalized for outputting any format, since the template
-- is language-agnostic, this implementation concentrates on HTML.
-- This does the actual generation of HTML, and provides support functions in the ldoc
-- table for the template
--
-- A fair amount of the complexity comes from operating in two basic modes; first, where
-- there is a number of modules (classic LuaDoc) or otherwise, where there is only one
-- module and the index contains the documentation for that module.
--
-- Like LuaDoc, LDoc puts similar kinds of documentation files in their own directories.
-- So module docs go into 'modules/', scripts go into 'scripts/', and so forth. LDoc
-- generalizes the idea of these project-level categories and in fact custom categories
-- can be created (refered to as 'kinds' in the code)

local template = require 'pl.template'
local tools = require 'ldoc.tools'

local html = {}


local quit = utils.quit

function html.generate_output(ldoc, args, project)
   local check_directory, check_file, writefile = tools.check_directory, tools.check_file, tools.writefile


   -- this generates the internal module/function references
   function ldoc.href(see)
      if see.href then -- explict reference, e.g. to Lua manual
         return see.href
      else
         return ldoc.ref_to_module(see.mod)..'#'..see.name
      end
   end

   -- this is either called from the 'root' (index or single module) or
   -- from the 'modules' etc directories. If we are in one of those directories,
   -- then linking to another kind is `../kind/name`; to the same kind is just `name`.
   -- If we are in the root, then it is `kind/name`.
   function ldoc.ref_to_module (mod)
      local base = "" -- default: same directory
      mod = mod or ldoc.module
      local kind, module = mod.kind, ldoc.module
      local name = mod.name -- default: name of module
      if not ldoc.single then
         if module then -- we are in kind/
            if module.type ~= type then -- cross ref to ../kind/
               base = "../"..kind.."/"
            end
         else -- we are in root: index
            base = kind..'/'
         end
      else -- single module
         if mod == ldoc.single then
            name = ldoc.output
            if not ldoc.root then base = '../' end
         elseif ldoc.root then -- ref to other kinds (like examples)
            base = kind..'/'
         else
            if module.type ~= type then -- cross ref to ../kind/
               base = "../"..kind.."/"
            end
         end
      end
      return base..name..'.html'
   end

   function ldoc.use_li(ls)
      if #ls > 1 then return '<li>','</li>' else return '','' end
   end

   function ldoc.display_name(item)
      if item.type == 'function' then return item.name..'&nbsp;'..item.args
      else return item.name end
   end

   function ldoc.no_spaces(s) return (s:gsub('%s','_')) end

   function ldoc.titlecase(s)
      return (s:gsub('(%a)(%a*)',function(f,r)
         return f:upper()..r
      end))
   end

   local module_template,err = utils.readfile (path.join(args.template,ldoc.templ))
   if not module_template then
      quit("template not found at '"..args.template.."' Use -l to specify directory containing ldoc.ltp")
   end

   local css = ldoc.css
   ldoc.output = args.output

   -- in single mode there is one module and the 'index' is the
   -- documentation for that module.
   ldoc.module = ldoc.single
   if ldoc.single and args.one then
      ldoc.kinds_allowed = {module = true, topic = true}
   end
   ldoc.root = true
   local out,err = template.substitute(module_template,{
      ldoc = ldoc,
      module = ldoc.module
    })
   ldoc.root = false
   if not out then quit("template failed: "..err) end

   check_directory(args.dir) -- make sure output directory is ok

   args.dir = args.dir .. path.sep

   check_file(args.dir..css, path.join(args.style,css)) -- has CSS been copied?

   -- write out the module index
   writefile(args.dir..args.output..args.ext,out)

   -- write out the per-module documentation
   -- in single mode, we exclude any modules since the module has been done;
   -- this step is then only for putting out any examples or topics
   ldoc.css = '../'..css
   for kind, modules in project() do
      kind = kind:lower()
      if not ldoc.single or ldoc.single and kind ~= 'modules' then
         check_directory(args.dir..kind)
         for m in modules() do
            ldoc.module = m
            ldoc.body = m.body
            if ldoc.body then
               ldoc.body = m.postprocess(ldoc.body)
            end
            out,err = template.substitute(module_template,{
               module=m,
               ldoc = ldoc
            })
            if not out then
               quit('template failed for '..m.name..': '..err)
            else
               writefile(args.dir..kind..'/'..m.name..args.ext,out)
            end
         end
      end
   end
   if not args.quiet then print('output written to '..args.dir) end
end

return html