--- **LIBEZT-1.0** Is a simple library for importing/rendering EZT templates
-- @class file
-- @name LIBEZT-1.0

--[[ LIBEZT-1.0

Revision: $Rev$
Author(s): Humbedooh
Description: EZT import library
License: Apache License, v/2.0

]]

local LIBEZT_MAJOR = "LibEZT-1.0"
-- version number of this file (automatically generated by SVN)
local LIBEZT_MINOR = tonumber(("$Rev$"):match("(%d+)")) or 10000;
local LIBEZT = false;
if LibStub then
	LIBEZT = LibStub:NewLibrary(LIBEZT_MAJOR, LIBEZT_MINOR)
	_G.LIBEZT = LIBEZT;
else
	if not _G.LIBEZT or (type(_G.LIBEZT) == "table" and _G.LIBEZT.rev < LIBEZT_MINOR) then
		_G.LIBEZT = {rev = LIBEZT_MINOR};
	end
	LIBEZT = _G.LIBEZT;
end
if not LIBEZT then return end

function LIBEZT:version()
    return LIBEZT_MINOR
end

function LIBEZT.parseargs(s)
    local arg = {};
    for w in s:gmatch("([%w:%-]+)") do table.insert(arg,w) end
    return arg;
end

function LIBEZT.at(s,e)
    local l = 1;
    for n = 1, e do if s:sub(n,n)=="\n" then l=l+1 end end
    return l
end

function LIBEZT:import(s, loose)
    local tremove, parseargs,tinsert = table.remove, LIBEZT.parseargs,table.insert;
    local stack = {};
    local top = {};
    tinsert(stack, top);
    local ni,c,class,args;
    local i, j = 1, 1;
    local ci, cj -- start and end of HTML comment (if any)
    local searchComment = true -- whether there are comments still to find
    while true do
        -- class: (alpha | '_') (alphanum | '_' | '-')*
        -- args = anything afterwards
        ni,j,class,args = s:find("%[([%l%u_][%w%-_]*)([^%]]*)%]", i);
        if not ni then break end
        --[[
            HTML comments may contain constructs that look like ezt sytnax, e.g. 
            <!--[if lt IE 9]> ... <![endif]-->

            In order to support HTML comments, we need to scan for either a comment or an EZT command
            However Lua does not support RE alternation, so this needs to be done as a separate search.
            
            Also Lua does not support a "continue" clause so we need to use a nested if
        ]]
      if searchComment then ci, cj = s:find("<!%-%-.-%-%->", i) end -- find next HTML comment (if any)
      if not ci then searchComment = False end -- no comment found; there cannot be any more
      if searchComment and ci < ni then -- the comment starts before the ezt command
          top[#top+1]=s:sub(i, cj);
          i = cj + 1 -- skip the comment
          -- and continue to look for next ezt command
      else
        -- found an ezt command outside an HTML comment        
        local text = s:sub(i, ni-1);
        if text:find("%S") then
            top[#top+1]=text;
        end
        if (class ~= "ezt" and class ~= "end" and class ~= "if" and class~= "is" and class~= "if-any" and class ~= "define" and class~= "for") then  -- empty element
            top[#top+1] ={class=class, args=parseargs(args), empty=true, ni=ni};
        elseif class ~= "end" then   -- start tag
         --   print("open " .. class)
            top = {class=class, args=parseargs(args), ni=ni};
            stack[#stack+1] = top;   -- new level
        elseif class == "end" then  -- end tag
            local toclose = tremove(stack);  -- pop the top and get the opening tag
            --print("close " .. toclose.class)
            top = stack[#stack];
            if #stack < 1 then
                --   print( ("%s: No opening tag found for <%s> (at line %u)!"):format("LibEZT", class, LIBEZT.at(s,ni)))
                return nil, ("%s: No opening tag found for <%s> (at line %u)!"):format("LibEZT", class, LIBEZT.at(s,ni));
            end
            top[#top+1] = toclose;
        end
        i = j+1;
      end
    end
    local text = s:sub(i);
    if not text:find("^%s*$") then
        local st = stack[#stack];
        st[#st+1] = text;
    end
    if #stack > 1 then
        local l = LIBEZT.at(s, (stack[#stack].ni or 0))
        print(("%s: EZT data ended without closing [%s] (at line %u)!"):format("LibEZT", stack[#stack].class, l))
        return nil, ("%s: EZT data ended without closing <%s> (at line %u)!"):format("LibEZT", stack[#stack].class, l);
    end
    return stack[1];
end

function LIBEZT.construct(self, child, defs)
    if type(child) == "string" then
        return child or ""
    elseif type(child) == "table" and #table > 0 then
      --  print("got a root")
        local rv = ""
        for k, v in pairs(child) do
            print(k) -- TODO this looks like a debug statement, should it still be enabled?
            rv = rv .. LIBEZT.construct(self, v, defs)
        end
        return rv
    elseif child.class then
        if child.class == "ezt" then
       --     print("Starting EZT...")
            local rv = ""
            for k, v in ipairs(child) do
                rv = rv .. LIBEZT.construct(self, v, defs)
            end
            return rv
        elseif child.class == "define" then
        --    print("got a define")
            local key = child.args[1]
            defs.strings[key] = child[1]
        --    print("set", key, child[1])
            return ""
        elseif child.class == "for" then
            local rv = ""
         --   print("Doing for...")
            if child.args[1] and defs.arrays[child.args[1]] then
                for x,y in pairs(defs.arrays[child.args[1]]) do
                    defs.strings[child.args[1]] = y
                    for k, v in ipairs(child) do
                        --print(k)
                        rv = rv .. LIBEZT.construct(self, v, defs)
                    end
                end
            end
            return rv
        elseif child.class == "if-any" then
            local rv = ""
           -- print("Doing if..")
            if child.args[1] then
                if defs.strings[child.args[1]] or defs.arrays[child.args[1]] then
                    for k, v in ipairs(child) do
                        rv = rv .. LIBEZT.construct(self, v, defs)
                    end
                end
            end
            return rv
        elseif child.class == "is" then
            local rv = ""
           -- print("Doing is..")
            rv = ""
            if #child.args == 2 then
                local a = defs.strings[child.args[1]] or nil
                local b = defs.strings[child.args[2]] or nil
                if a == b then
                    for k, v in ipairs(child) do
                        rv = rv .. LIBEZT.construct(self, v, defs)
                    end
                end
            end
            return rv
        elseif child.empty then
            --print(child.class)
            return tostring(defs.strings[child.class] or "")
        end
    else
        local rv = ""
        for k, v in pairs(child) do
            rv = rv .. LIBEZT.construct(self, v, defs)
        end
        return rv
    end
end

return LIBEZT