Editing Module:InfoboxImage

-- Inputs:
--    image - Can either be a bare filename (with or without the File:/Image: prefix) or a fully formatted image link
--    page - page to display for multipage images (DjVu)
--    size - size to display the image
--    maxsize - maximum size for image
--    sizedefault - default size to display the image if size param is blank
--    alt - alt text for image
--    title - title text for image
--    border - set to yes if border
--    center - set to yes, if the image has to be centered
--    upright - upright image param
--    suppressplaceholder - if yes then checks to see if image is a placeholder and suppresses it
--    link - page to visit when clicking on image
--    class - HTML classes to add to the image
-- Outputs:
--    Formatted image.
-- More details available at the "Module:InfoboxImage/doc" page

local i = {}

-- List of placeholder images and tracking categories stored in [[Module:InfoboxImage/data]]
-- Other constants:
--   the system-wide default thumbnail size (in px)
local defaultThumbnailSize = 250

-- If page is not a user page, return tracking category. Else return empty.
local function trackingCat(cat)
	local ns = mw.title.getCurrentTitle().nsText:lower()
    local categories = mw.loadData('Module:InfoboxImage/data').categories
	return (ns ~= 'user' and ns ~= 'user talk' and categories[cat]) or ""
end

-- Determine whether image is a placeholder
function i.IsPlaceholder(image)
    -- change underscores to spaces
    image = mw.ustring.gsub(image, "_", " ");
    assert(image ~= nil, 'mw.ustring.gsub(image, "_", " ") must not return nil')
    -- if image starts with [[ then remove that and anything after |
    if mw.ustring.sub(image,1,2) == "[[" then
        image = mw.ustring.sub(image,3);
        image = mw.ustring.gsub(image, "([^|]*)|.*", "%1");
        assert(image ~= nil, 'mw.ustring.gsub(image, "([^|]*)|.*", "%1") must not return nil')
    end
    -- Trim spaces
    image = mw.ustring.gsub(image, '^[ ]*(.-)[ ]*$', '%1');
    assert(image ~= nil, "mw.ustring.gsub(image, '^[ ]*(.-)[ ]*$', '%1') must not return nil")
    -- remove prefix if exists
    local allNames = mw.site.namespaces[6].aliases
    allNames[#allNames + 1] = mw.site.namespaces[6].name
    allNames[#allNames + 1] = mw.site.namespaces[6].canonicalName
    for i, name in ipairs(allNames) do
        if mw.ustring.lower(mw.ustring.sub(image, 1, mw.ustring.len(name) + 1)) == mw.ustring.lower(name .. ":") then
            image = mw.ustring.sub(image, mw.ustring.len(name) + 2);
            break
        end
    end
    -- Trim spaces
    image = mw.ustring.gsub(image, '^[ ]*(.-)[ ]*$', '%1');
    -- capitalise first letter
    image = mw.ustring.upper(mw.ustring.sub(image,1,1)) .. mw.ustring.sub(image,2);

    local placeholder_image = mw.loadData('Module:InfoboxImage/data').placeholder_image
    return placeholder_image[image]
end

local function isempty(x)
    return (not x) or x == ""
end

-- Main entry point
function i.InfoboxImage(frame)
    local image = frame.args["image"];
    
    if isempty(image) then
        return "";
    end
    if image == "&nbsp;" then
        return image;
    end
    if frame.args["suppressplaceholder"] ~= "no" then
        if i.IsPlaceholder(image) == true then
            return "";
        end
    end
    
    if string.find(image, "^%[*https?:") then
		-- Error category.
		return trackingCat("url_image_links")
	end

    if mw.ustring.sub(image,1,2) == "[[" then
        -- search for thumbnail images and add to tracking cat if found
        local cat = "";
        if mw.title.getCurrentTitle().namespace == 0 and (mw.ustring.find(image, "|%s*thumb%s*[|%]]") or mw.ustring.find(image, "|%s*thumbnail%s*[|%]]")) then
            cat = trackingCat("thumbnail_images")
        end
        return image .. cat;
    elseif mw.ustring.sub(image,1,2) == "{{" and mw.ustring.sub(image,1,3) ~= "{{{" then
        return image;
    elseif mw.ustring.sub(image,1,1) == "<" then
        return image;
    elseif mw.ustring.sub(image,1,8) == mw.ustring.char(127).."'\"`UNIQ" then
        -- Found strip marker at begining, so pass don't process at all
        return image;
    else
        local result = "";
        local page = frame.args["page"];
        local upright = frame.args["upright"] or ""
        local size = frame.args["size"];
        local maxsize = frame.args["maxsize"];
        local sizedefault = frame.args["sizedefault"];
        local alt = frame.args["alt"];
        local link = frame.args["link"];
        local title = frame.args["title"];
        local border = frame.args["border"];
        local thumbtime = frame.args["thumbtime"] or "";
        local center = frame.args["center"];
        local class = frame.args["class"];
        
        -- remove prefix if exists
        local allNames = mw.site.namespaces[6].aliases
        allNames[#allNames + 1] = mw.site.namespaces[6].name
        allNames[#allNames + 1] = mw.site.namespaces[6].canonicalName
        for i, name in ipairs(allNames) do
            if mw.ustring.lower(mw.ustring.sub(image, 1, mw.ustring.len(name) + 1)) == mw.ustring.lower(name .. ":") then
                image = mw.ustring.sub(image, mw.ustring.len(name) + 2);
                break
            end
        end
        
        if not isempty(maxsize) then
            -- if no sizedefault nor upright, then set to maxsize
            if isempty(sizedefault) and isempty(upright) then
                sizedefault = maxsize
            end
            -- check to see if size bigger than maxsize
            local maxsizenumber = tonumber(mw.ustring.match(maxsize,"%d*")) or 0;
            if not isempty(size) then
                local sizenumber = tonumber(mw.ustring.match(size,"%d*")) or 0;
                if sizenumber > maxsizenumber and maxsizenumber > 0 then
                    size = maxsize;
                end
            end
            -- check to see if upright bigger than maxsize (at default preferred size)
            if not isempty(upright) then
                local uprightnumber = tonumber(upright) or (upright == "yes" and 0.75) or 0
                if uprightnumber*defaultThumbnailSize > maxsizenumber and maxsizenumber > 0 then
                    upright = tostring(maxsizenumber/defaultThumbnailSize)
                end
            end
        end
        -- add px to size if just a number
        if (tonumber(size) or 0) > 0 then
            size = size .. "px";
        end
        -- add px to sizedefault if just a number
        if (tonumber(sizedefault) or 0) > 0 then
            sizedefault = sizedefault .. "px";
        end
        
        result = "[[File:" .. image;
        if not isempty(page) then
            result = result .. "|page=" .. page;
        end
        if not isempty(size) then
            result = result .. "|" .. size;
        elseif not isempty(sizedefault) and isempty(upright) then
            result = result .. "|" .. sizedefault;
        else
            result = result .. "|frameless";
        end
        if center == "yes" then
            result = result .. "|center"
        end
        if not isempty(alt) then
            result = result .. "|alt=" .. alt;
        end
        if not isempty(link) then
            result = result .. "|link=" .. link;
        end
        if border == "yes" then
            result = result .. "|border";
        end
        if upright == "yes" then
            result = result .. "|upright";
        elseif upright ~= "" then
            result = result .. "|upright=" .. upright;
        end
        if thumbtime ~= "" then
            result = result .. "|thumbtime=" .. thumbtime;
        end
        if not isempty(class) then
            result = result .. "|class=" .. class;
        end
        -- if alt value is a keyword then do not use as a description
        if alt == "thumbnail" or alt == "thumb" or alt == "frameless" or alt == "left" or alt == "center" or alt == "right" or alt == "upright" or alt == "border" or mw.ustring.match(alt or "", '^[0-9]*px$', 1) ~= nil then
            alt = nil;
        end
        if not isempty(title) then
            -- does title param contain any templatestyles? If yes then set to blank.
            if mw.ustring.match(frame:preprocess(title), 'UNIQ%-%-templatestyles', 1) ~= nil then
                title = nil;
            end
        end
        if not isempty(title) then
            result = result .. "|" .. title;
        end
        result = result .. "]]";
        
        return result;
    end
end

return i;