--[[  
 
This module generates links to ships in the Naval Vessel Register (nvr.navy.mil) database.  
It is used by Template:Naval Vessel Register URL and Template:Naval Vessel Register service craft URL
 
Please do not modify this code without applying the changes first at Module:Naval Vessel Register URL/sandbox and testing 
at Module:Naval Vessel Register URL/sandbox/testcases and Module talk:Naval Vessel Register URL/sandbox/testcases.
 
Authors and maintainers:
* User:RP88

]]

require('strict')
local get_args = require ('Module:Arguments').getArgs;
local data_t = mw.loadData ('Module:Naval Vessel Register URL/data');


--[[--------------------------< M A K E _ E R R O R _ M E S S A G E >------------------------------------------

General purpose error message function to render error messages and categorization

]]

local function make_error_message (output, prefix, item, suffix, srv_craft)
	local category = '';														-- for concatenation
	
	if 0 == mw.title.getCurrentTitle().namespace then							-- article namespace
		category = '[[Category:WPSHIPS:Template_errors]]';						-- categorize only from article namespace
	end
	
	table.insert (output, '<span style="font-size:100%" class="error">')
	table.insert (output, prefix);
	table.insert (output, item);
	table.insert (output, suffix);
	if srv_craft then
		table.insert (output, ' ([[Template:Naval Vessel Register service craft URL#Error messages|help]])</span>');
	else
		table.insert (output, ' ([[Template:Naval Vessel Register URL#Error messages|help]])</span>');
	end
	table.insert (output, category);
	return
end


--[[--------------------------< _ N V R _ U R L _M A K E >-----------------------------------------------------

common function to return an NVR url when given 
]]

local function _nvr_url_make (args_t)
	local output = {};

	if (not args_t[1]) and (not args_t['id']) then
		make_error_message (output, 'required parameter missing', '', '');
		return table.concat (output);
	end

	local hull = args_t['id'] or args_t[1];
	local hull_designator;														-- for use with |name= parameter rendering
	local hull_prefix;
	local title = args_t["title"] or args_t[2];
	
	hull = mw.text.trim (hull):upper():gsub ('[ _%-]+', '-');					-- no leading/trailing whitespace, uppercase; convert spaces, underscores, hyphens to hyphens

	local patterns_t = {														-- patterns for various NVR hull classification
		{'^(T)%-?(%u+)%-?(%d+)$', '%1-%2-%3', '^T%-%u+'},						-- for certain auxilliaries that have a 'T-' prefix
		{'^(%u+)%-?(%d+)$', '%1-%2', '^%u+'},									-- most common hull designator format
		{'^(AFDB)%-?(%d+%u?)$', '%1-%2', '^%u+'},								-- special case for AFDB drydock sections
		{'^AFSB%-?%(I%)%-?15', 'AFSB-(I)-15', 'AFSB'},							-- special case for Ponce (AFSB-(I)-15)
		};
	
	for _, pattern_t in ipairs (patterns_t) do									-- spin through the patterns_t sequence
		if hull:match (pattern_t[1]) then										-- if a match
			hull = hull:gsub (pattern_t[1], pattern_t[2]);						-- ensure proper format
			hull_prefix = hull:match (pattern_t[3]);							-- and extract the alpha hull prefix (SSBN from SSBN-659)
			break;
		end
	end

	if not hull_prefix then
		if ({['CONSTITUTION'] = true, ['MAINE'] = true, ['TEXAS'] = true})[hull] then	-- special case for these three ships which do not have standard hull designators in NVR
			hull_prefix = hull;													-- so use ship name to index into data table
		else
			make_error_message (output, 'malformed hull classification symbol: ', hull, '');
			return table.concat (output);
		end
	end
	
	hull_designator = hull;														-- copy for use with |name= parameter

	if not data_t[hull_prefix] then											-- is there a group for the hull number?
		make_error_message (output, 'unable to find group: [\'', hull_prefix, '\'] in [[Module:Naval Vessel Register URL/data]]');
		return table.concat (output);
	end

	if not data_t[hull_prefix][hull] then										-- is there a hull number
		make_error_message (output, 'unable to find hull classification symbol: [\'', hull, '\'] in [[Module:Naval Vessel Register URL/data]]');
		return table.concat (output);
	end

	local nvr_id = data_t[hull_prefix][hull][1];								-- try to fetch nvr id
	if not title and (args_t['name'] and '' ~= args_t['name']) then
		title = data_t[hull_prefix][hull][2];
		if not title or '' == title then
			title = nil;														-- ensure
		elseif 'no name' == title:lower() then									-- new construction capital ships, and many service craft
			title = title .. ' (' .. hull_designator .. ')';
		elseif 'nh' == args_t['name'] then										-- special keyword to render name and hull designator
			title = '\'\'' .. data_t[hull_prefix][hull][2] .. '\'\' (' .. hull_designator .. ')';
		else
			title = '\'\'' .. data_t[hull_prefix][hull][2] .. '\'\'';		-- just the name
		end
	end

	if (nil ~= nvr_id) and ('' ~= nvr_id) then									-- there appears to be an identifier, so use it
		if title then															-- if there is a title then make an external link from it
			table.insert (output, '[');											-- opening bracket
		end
		table.insert (output, 'https://www.nvr.navy.mil/nvr/getHull.htm?shipId=');	-- create the url
		table.insert (output, nvr_id);
		if title then
			table.insert (output, ' ');											-- required space
			table.insert (output, title);										-- title
			table.insert (output, ']');											-- and closing bracket
		end
		
	else																		-- no identifier
		make_error_message (output, 'no identifier for hull classification symbol: [\'', hull, '\'] in [[Module:Naval Vessel Register URL/data]]');
	end
	
	return table.concat (output);												-- and done
end


--[[--------------------------< N V R _ U R L _M A K E >-------------------------------------------------------

{{#invoke:Naval Vessel Register URL|nvr_url_make|1=|title=}}

Parameters:
    {{{1}}} or |id=: required; the ship's hull designator: T-ARC-7, SSBN-658, YTB-760, etc
    {{{2}}} or |title=: optional; a title or label for the link

]]

local function nvr_url_make (frame)
	local args_t = get_args (frame);
	return _nvr_url_make (args_t)
end


--[[--------------------------< E X P O R T S >----------------------------------------------------------------
]]

return {
	nvr_url_make = nvr_url_make,												-- entry point when called from a template
	
	_nvr_url_make = _nvr_url_make,												-- entry point when called from a module
	}