local p = {}
local getArgs = require('Module:Arguments').getArgs

-- Returns a table with the keys of the passed table as its values
local function getTableKeys(tbl)
	local keys = {}
	for k,_ in pairs(tbl) do
		keys[#keys + 1] = k
	end

	table.sort(keys)
	return keys
end

-- Construct a table of the tagged CSDs and any arguments passed in for each CSD
-- Example format: |G6|rationale{{=}}G6 rationale|xfd|G7|rationale{{=}}G7 rationale
local function constructCsdTable(args)
	local tbl = {}
    local current = ''															-- Code of current CSD being processed. Its value will be the last CSD-like param read (eg 'G6')
    local size = 0
    for k,v in pairs(args) do
        if string.match(v, '^[GgAaFfCcUuRrTtPp]%d%d?$') then						-- Begin collecting args for a new CSD
            current, size = string.lower(v), 0
            tbl[current] = {['size'] = size}
        else																	-- Add the arg to the CSD being processed (ie, the corresponding CSD)
        	local arg = mw.text.split(v, '=')
        	tbl[current][string.lower(arg[1])] = arg[2]
        	size = size + 1														-- Increment the 'size', ie number of params passed for a particular CSD
        	tbl[current]['size'] = size
        end
    end
    
    return tbl
end

-- Build the Db-meta wrapper template
local function build(frame, args)
	local passThruArgs = {'rationale', 'xfd', 'user', 'blanked', 'url', 'url2', 'url3', 'source', 'article', 'location', 'filename', 'criterion'} -- Arguments we'll pass through unchanged to the Db-meta wrapper
	local csdTable = constructCsdTable(args)
	local csdKeys = getTableKeys(csdTable)
	--if true then return mw.dumpObject(csdTable) end

    local builtCsdTemplates = {}
    local summary = ""
    
    -- Loop through CSDs (eg G1, G2)
    local n = 0
    for k,v in pairs(csdTable) do
    	n = n + 1
    	local templateArgs = {
    		['raw'] = 'yes',
    		['nocat'] = 'true'													-- for test purposes
        }
        
        -- Add to summary the name of the CSD. Plus open brackets if we've got extra params
        summary = summary .. string.upper(k) .. (v['size'] > 0 and ' (' or '')
        
        -- add values to templateArgs (and summary) in any custom params we got for this CSD, eg Rationale, URL
        for _,arg in ipairs(passThruArgs) do
        	if v[arg] then
        		templateArgs[arg] = v[arg]
        		summary = summary .. arg .. ': ' .. v[arg] .. (v['size'] > _ and ', ' or '')
        	end
        end
        -- Close brackets if we had custom params. Add a comma if we've got another CSD
        summary = summary .. (v['size'] > 0 and ')' or '') .. (#csdKeys > n and ', ' or '')
    	
    	-- Save the built template
    	table.insert(builtCsdTemplates, frame:expandTemplate{ title = 'Db-'..k, args = templateArgs })
    end
    
    -- Construct Db-meta wrapper, composed of all the built CSD templates
    local dbTemplate = frame:expandTemplate{ title = 'Db-meta', args = {
    		[1] = '&#32;for the following reasons:</b><ul><li>'..table.concat(builtCsdTemplates, '</li><li>') .. '</li></ul> <b>The page may be deleted under any criterion that is valid',
    		['criterion'] = 'NA',
    		['temp'] = 'Db-notice-multiple',
    		['temp2'] = '|'..table.concat(csdKeys, '|'),
    		['summary'] = 'Multiple reasons: ' .. summary,
    		
    		-- forward given params to Db-meta
    		['bot'] = args['bot'] or '',
    		['blanked'] = args['blanked'] or (csdTable['g10'] and 'yes') or '',
    		['divblank'] = args['divblank'] or (csdTable['g10'] and 'yes') or '',
    		['help'] = args['help'] or '',
    }}

    return dbTemplate
end

-- Exports
function p.main(frame)
	local args = getArgs(frame)
	return build(frame, args)
end

-- Test
function p.dump(frame)
	return mw.dumpObject(mw.text.unstripNoWiki(frame.args[1]))
end

return p