Editing Module:File link

-- This module provides a library for formatting image wikilinks.

local libraryUtil = require('libraryUtil')
local checkType = libraryUtil.checkType

local image = {}

function image.new(filename)
	checkType('image.new', 1, filename, 'string', true)
	local obj, data = {}, {}
	
	local checkSelf = libraryUtil.makeCheckSelfFunction(
		'image',
		'image',
		obj,
		'image object'
	)
	
	-- Set the filename if we were passed it as an input to image.new.
	if filename then
		data.theName = filename
	end
	
	function data:name(s)
		checkSelf(self, 'image:name')
		checkType('image:name', 1, s, 'string')
		data.theName = s
		return self
	end
	
	function data:format(s, filename)
		checkSelf(self, 'image:format')
		checkType('image:format', 1, s, 'string', true)
		checkType('image:format', 2, format, 'string', true)
		local validFormats = {
			thumb = true,
			thumbnail = true,
			frame = true,
			framed = true,
			frameless = true
		}
		if s == nil or validFormats[s] then
			data.theFormat = s
			data.theFormatFilename = filename
		else
			error(string.format(
				"bad argument #1 to 'image:format' ('%s' is not a valid format)",
				s
			), 2)
		end
		return self
	end

	local function sizeError(methodName)
		-- Used for formatting duplication errors in size-related methods.
		error(string.format(
			"duplicate size argument detected in '%s'"
			.. " ('upright' cannot be used in conjunction with height or width)",
			methodName
		), 3)
	end
	
	function data:width(px)
		checkSelf(self, 'image:width')
		checkType('image:width', 1, px, 'number', true)
		if px and data.isUpright then
			sizeError('image:width')
		end
		data.theWidth = px
		return self
	end
	
	function data:height(px)
		checkSelf(self, 'image:height')
		checkType('image:height', 1, px, 'number', true)
		if px and data.isUpright then
			sizeError('image:height')
		end
		data.theHeight = px
		return self
	end
	
	function data:upright(isUpright, factor)
		checkSelf(self, 'image:upright')
		checkType('image:upright', 1, isUpright, 'boolean', true)
		checkType('image:upright', 2, factor, 'number', true)
		if isUpright and (data.theWidth or data.theHeight) then
			sizeError('image:upright')
		end
		data.isUpright = isUpright
		data.uprightFactor = factor
		return self
	end
	
	function data:resetSize()
		checkSelf(self, 'image:resetSize')
		for i, field in ipairs{'theWidth', 'theHeight', 'isUpright', 'uprightFactor'} do
			data[field] = nil
		end
		return self
	end
	
	function data:location(s)
		checkSelf(self, 'image:location')
		checkType('image:location', 1, s, 'string', true)
		local validLocations = {
			right = true,
			left = true,
			center = true,
			none = true
		}
		if s == nil or validLocations[s] then
			data.theLocation = s
		else
			error(string.format(
				"bad argument #1 to 'image:location' ('%s' is not a valid location)",
				s
			), 2)
		end
		return self
	end
	
	function data:alignment(s)
		checkSelf(self, 'image:alignment')
		checkType('image:alignment', 1, s, 'string', true)
		local validAlignments = {
			baseline = true,
			middle = true,
			sub = true,
			super = true,
			['text-top'] = true,
			['text-bottom'] = true,
			top = true,
			bottom = true
		}
		if s == nil or validAlignments[s] then
			data.theAlignment = s
		else
			error(string.format(
				"bad argument #1 to 'image:alignment' ('%s' is not a valid alignment)",
				s
			), 2)
		end
		return self
	end
	
	function data:border(hasBorder)
		checkSelf(self, 'image:border')
		checkType('image:border', 1, hasBorder, 'boolean', true)
		data.hasBorder = hasBorder
		return self
	end
	
	function data:link(s)
		checkSelf(self, 'image:link')
		checkType('image:link', 1, s, 'string', true)
		data.theLink = s
		return self
	end
	
	function data:alt(s)
		checkSelf(self, 'image:alt')
		checkType('image:alt', 1, s, 'string', true)
		data.theAlt = s
		return self
	end
	
	function data:caption(s)
		checkSelf(self, 'image:caption')
		checkType('image:caption', 1, s, 'string', true)
		data.theCaption = s
		return self
	end
	
	function data:render()
		checkSelf(self, 'image:render')
		local ret = {}
		
		-- Image name.
		if not data.theName then
			error('image:render: no image name was found')
		end
		ret[#ret + 1] = 'File:' .. data.theName
		
		-- Image format
		if data.theFormat and data.theFormatFilename then
			ret[#ret + 1] = data.theFormat .. '=' .. data.theFormatFilename
		elseif data.theFormat then
			ret[#ret + 1] = data.theFormat
		end
		
		-- Border
		if data.hasBorder then
			ret[#ret + 1] = 'border'
		end
		
		-- Location
		ret[#ret + 1] = data.theLocation

		-- Alignment
		ret[#ret + 1] = data.theAlignment
		
		-- Size
		if data.isUpright and data.uprightFactor then
			ret[#ret + 1] = 'upright=' .. tostring(data.uprightFactor)
		elseif data.isUpright then
			ret[#ret + 1] = 'upright'
		elseif data.theWidth and data.theHeight then
			ret[#ret + 1] = string.format('%dx%dpx', data.theWidth, data.theHeight)
		elseif data.theWidth then
			ret[#ret + 1] = tostring(data.theWidth) .. 'px'
		elseif data.theHeight then
			ret[#ret + 1] = string.format('x%dpx', data.theHeight)
		end
		
		-- Link
		if data.theLink then
			ret[#ret + 1] = 'link=' .. data.theLink
		end
		
		-- Alt
		if data.theAlt then
			ret[#ret + 1] = 'alt=' .. data.theAlt
		end
		
		-- Caption
		ret[#ret + 1] = data.theCaption
		
		return string.format('[[%s]]', table.concat(ret, '|'))
	end
	
	local privateFields = {
		theName = true,
		theFormat = true,
		theFormatFilename = true,
		theWidth = true,
		theHeight = true,
		isUpright = true,
		uprightFactor = true,
		theLocation = true,
		theAlignment = true,
		hasBorder = true,
		theLink = true,
		theAlt = true,
		theCaption = true
	}
	
	local readOnlyFields = {}
	for field in pairs(data) do
		readOnlyFields[field] = true
	end
	readOnlyFields.theName = nil -- This is set if a filename is given to image.new, so remove it.
	
	local function restrictedFieldError(key, restriction)
		error(string.format(
			"image object field '%s' is %s",
			tostring(key),
			restriction
		), 3)
	end
	
	setmetatable(obj, {
		__index = function (t, key)
			if privateFields[key] then
				restrictedFieldError(key, 'private')
			else
				return data[key]
			end
		end,
		__newindex = function (t, key, value)
			if privateFields[key] then
				restrictedFieldError(key, 'private')
			elseif readOnlyFields[key] then
				restrictedFieldError(key, 'read-only')
			else
				data[key] = value
			end
		end,
		__tostring = function (t)
			return t:render()
		end,
		__pairs = function ()
			local temp = {}
			for k, v in pairs(data) do
				if not privateFields[k] then
					temp[k] = v
				end
			end
			return pairs(temp)
		end
	})
	
	return obj
end

return image