-- Helper function: remove all image inlines from a list of inlines.
local function remove_images(inlines)
	local result = {}
	for _, item in ipairs(inlines) do
		if item.t ~= "Image" then
			table.insert(result, item)
		end
	end
	return result
end

-- Build a bullet list representing the table of contents.
local function build_toc(doc)
	local toc_items = {}
	for _, block in ipairs(doc.blocks) do
		if block.t == "Header" then
			local clean_inlines = remove_images(block.content)
			local header_text = pandoc.utils.stringify(clean_inlines)
			if header_text ~= "" then
				local link = pandoc.Link(clean_inlines, "#" .. block.identifier)
				table.insert(toc_items, { link })
			end
		end
	end
	return pandoc.BulletList(toc_items)
end

-- The Pandoc function runs after the document is fully constructed.
function Pandoc(doc)
	local toc = build_toc(doc)
	table.insert(doc.blocks, 1, toc) -- Insert the TOC at the very beginning of the document.
	return doc
end