-- **********************************************************************
-- * Html page renderer
-- * 
-- * version 0.1
-- *
-- * (c) 2005 Hi-Project Ltd. 
-- **********************************************************************

require "webserver.encoding"
require "common.errors"

module "htemplate"

local TK_VARNAME = "([%w_']*)" -- variable name pattern eg. my_funny_varname
local TK_PREFIX  = "%w*:"
local TK_START   = "{$"
local TK_END     = "$}"

local PATTERNS = { 
    parameter = "", 		-- parses function input parameters
	variable  = "VAR:",
	checkbox  = "CB:"
}

-- removes the unused tokens
function cleanup_buffer(htemp)
   if htemp == nil then return nil end   
   table.foreach(PATTERNS, function(k,v) 
   	   local w = ""   
   	   local prefix = v
	   for w in string.gfind(htemp, TK_START..prefix..TK_VARNAME..TK_END) do
     	htemp = string.gsub(htemp, TK_START..prefix..w..TK_END, "")         
   	   end    	   
   end)
   return htemp
end

-- parses global variable {$VAR:xxx$}
function parse_global_variables(htemp)
   if htemp==nil then return nil end   
   local w = ""
   for w in string.gfind(htemp, TK_START..PATTERNS.variable..TK_VARNAME..TK_END) do
     htemp = string.gsub(htemp, TK_START..PATTERNS.variable..w..TK_END, str_encode(getfenv()[w]))         
   end      
   return htemp
end

-- parses checkbox {$CB:xxx$}
function parse_checkbox(htemp,name,value)
   if htemp==nil then return nil end   
   if value~="0" and value~="" then 
   	 htemp = string.gsub(htemp, name, "checked") 
   else
   	 htemp = string.gsub(htemp, name, " ") 
   end      
   return htemp
end

-- 
-- API call
-- Template Buffer renderer
-- 
function parsebuffer(ht,func_result)
   if ht==nil then 
   	   LUNAERROR.seterrorbyname("TEMPLATE_NOTFOUND")
       return LUNAERROR.geterrormessage() 
   end  
   func_result = table_encode(func_result) or {}
   table.foreach(func_result, function(k,v)
     if k then
         -- parameter
         ht = string.gsub(ht, TK_START..k..TK_END, v)        
         -- checkbox
         if string.gfind(ht,TK_START..PATTERNS.checkbox..k..TK_END) then
            ht = parse_checkbox(ht,TK_START..PATTERNS.checkbox..k..TK_END,v)
   	    end   	    
     end
   end)
   -- global vars
   ht = parse_global_variables(ht)
   ht = cleanup_buffer(ht)   
   if ht==nil then
   	   LUNAERROR.seterrorbyname("TEMPLATE_NOTPARSED")
       return LUNAERROR.geterrormessage()
   else
   		return ht
   end
end

--------------------------------------------------------------------------
-- Initialization
--------------------------------------------------------------------------
LUNAERROR.adderror("TEMPLATE_NOTFOUND", 101,  "HTML TEMPLATE NOT FOUND", "EN")
LUNAERROR.adderror("TEMPLATE_NOTPARSED", 102, "HTML TEMPLATE PARSING ERROR", "EN")