-- module table
local Standardfarbe = {
	config = {
		colorJSON = "Vorlage:Standardfarbe/colors.json",
		errorOutput = "<span class=\"error\">Fehler in [[Vorlage:Standardfarbe]]: %s</span>"
	},
	colors = { },
	serial = ""
}
local Failsafe = Standardfarbe

Standardfarbe.formatError = function ( message )
	-- format error message
	-- parameters:
	--   message: (string) raw error message
	-- returns:
	--   (string) formatted error message
	return string.format( Standardfarbe.config.errorOutput, message )
end

Standardfarbe.iterateColorGroup = function ( group, key )
	-- return color value
	-- parameters:
	--   group: (table) color group
	--   key:   (string) key to find
	-- returns:
	--   (bool, table) color block found, color block table
	
	for _, block in ipairs( group ) do
		for _, k in ipairs( block.keys ) do
			if k == key then
				return true, block.colors
			end
		end
	end
	
	return false, {}
end

Standardfarbe.loadColorsJson = function ( page )
	-- load colors from json page
	-- parameters:
	--   page: (string) path to color json page
	-- returns:
	--   (bool) true or false by success/fault
	
	local success, c = pcall( mw.loadJsonData, page )
	if type( c ) == "table" then
		Standardfarbe.colors = c
	end
	
	return success
end

Standardfarbe.getColor = function ( group, key, mode, ucase )
	-- return color value
	-- parameters:
	--   group:  (string) color group
	--   key:    (string) color key
	--   mode:   (string) display mode
	--   ucase:  (bool)   uppercase color codes
	-- returns:
	--   (string) hex color code
	
	local blockColors -- colors in block
	local groupColors -- colors in group
	local found       -- color block found
	local color       -- color value

	-- load defined colors
	if Standardfarbe.loadColorsJson( Standardfarbe.config.colorJSON ) == false then
		return ""
	end

	-- find color group
	groupColors = Standardfarbe.colors[group]
	if type( groupColors ) ~= "table" then
		return Standardfarbe.formatError( "color group not found" )
	end
	
	-- find color block with key
	found, blockColors = Standardfarbe.iterateColorGroup( groupColors, key )
	if found == false then
		return Standardfarbe.formatError( "color key not found" )
	end
	
	-- find color in block
	if mode == "" then
		mode = "light"
	end
	color = blockColors[mode]
	if color == nil then
		color = blockColors["light"]
		if color == nil then
			return Standardfarbe.formatError( "no matching color mode" )
		end
	end
	
	-- uppercase, if wanted
	if ucase then
		color = string.upper( color )
	end
	
	-- return color value
	return color
end

-- export table
local p = { }

p.outputDefinedColors = function ( frame )
	-- return wikitable with defined colors
	-- parameters:
	--   frame: (table) wiki environment frame
	-- returns:
	--   (string) wikitable code
	
	local wtbmain -- main wikitable
	local wtbhead -- wikitable head
	local wtbrow  -- color row
	local wtbcol  -- color cell
	local keys    -- color keys
	local count   -- color count

	-- load defined colors
	if Standardfarbe.loadColorsJson( Standardfarbe.config.colorJSON ) == false then
		return ""
	end
	
	-- create wikitable
	wtbmain = mw.html.create( "table" ):addClass( "wikitable" )
	
	-- create headline
	wtbhead = mw.html.create( "tr" )
		:node( mw.html.create( "th" ):wikitext( "Gruppe" ):attr( "rowspan", 2 ) )
		:node( mw.html.create( "th" ):wikitext( "Schlüssel" ):attr( "rowspan", 2 ) )
		:node( mw.html.create( "th" ):wikitext( "Farbe/Modus" ):attr( "colspan", 4 ) )
	wtbmain:node( wtbhead )
	wtbhead = mw.html.create( "tr" )
		:node( mw.html.create( "th" ):wikitext( "Hell" ):attr( "colspan", 2 ) )
		:node( mw.html.create( "th" ):wikitext( "Dunkel" ):attr( "colspan", 2 ) )
	wtbmain:node( wtbhead )
	
	-- create lines for colors in groups
	for group, groupColors in pairs( Standardfarbe.colors ) do
		count = 0
		for _, _ in ipairs( groupColors ) do
			count = count + 1	
		end
		
		for i, color in ipairs( groupColors ) do
			wtbrow = mw.html.create( "tr" )

			-- create first cell that has the group name
			if i == 1 then
				wtbrow:node( mw.html.create( "td" ):attr( "rowspan", count ):wikitext( group ) )
			end
			
			-- color keys
			keys = ""
			for _, key in ipairs( color.keys ) do
				code = mw.html.create( "code" ):wikitext( key )
				keys = keys .. tostring( code ) .. " "
			end
			wtbrow:node( mw.html.create( "td" ):wikitext( keys ) )
			
			-- colors
			wtbcol = mw.html.create( "td" ):wikitext( "#" .. color.colors["light"] )
			if color.colors["dark"] == nil then
				wtbcol:attr( "colspan", 3 )
				wtbcol:css( "text-align", "center" )
			end
			wtbrow:node( wtbcol )
			wtbrow:node( mw.html.create( "td" ):css( "background-color", "#" .. color.colors["light"] ):wikitext("&nbsp;") )
			
			if color.colors["dark"] ~= nil then
				wtbrow:node( mw.html.create( "td" ):wikitext( "#" .. color.colors["dark"] ) )
				wtbrow:node( mw.html.create( "td" ):css( "background-color", "#" .. color.colors["dark"] ):wikitext("&nbsp;") )
			end
			
			-- add current row to table
			wtbmain:node( wtbrow )
		end
	end
	
	-- return wikitable
	return tostring( wtbmain )
end

p.f = function ( frame )
	-- return color value, access from templates
	-- parameters:
	--   frame: (table) wiki environment frame
	-- returns:
	--   (string) hex color code
	
	local args	 -- arguments of template call
	local group  -- color group
	local key    -- color key
	local mode   -- display mode
	local ucase  -- uppercase color values
	local nowiki -- enclose in nowiki tags
	
	-- get template parameters
	args   = frame:getParent().args
	group  = args[1] or ""
	key    = args[2] or ""
	mode   = args["mode"] or "light"
	ucase  = ( args["ucase"] == "1" )
	nowiki = ( args["nowiki"] == "1" )
	
	-- call main and return
	local success, r = pcall( Standardfarbe.getColor, group, key, mode, ucase )
	if not success then
		return Standardfarbe.formatError( "color call failed" )
	end
	
	-- apply nowiki
	if nowiki then
		r = frame:extensionTag( "nowiki", r )
	end
	
	-- return
	return r
end

setmetatable( p,  { __call = function ( func, ... )
                                 setmetatable( p, nil )
                                 return Failsafe
                             end } )

return p