local hp = require "gumbo"
local b64 = require "base64"

local banner = "_30q-"
local docBody = "_39k5"
local title = "_4lmk"
local bold = "_4yxo"
local italics = "_4yxp"
local emoji = "_47e3"
local hidden = "_7oe"
local date = "_39g5"

local namespace = "fbdoc"

local pageUrl

function treat(node, output)
	
	if node.nodeName == "#text" then
		table.insert(output, node.data or "")
	
	elseif node.nodeName == "DIV" or node.nodeName == "LI" or node.nodeName == "FIGURE" then
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, "\n\n")
		
	elseif node.nodeName == "SPAN" and node.className:match(bold) then
		table.insert(output, "**")
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, "**")
		
	elseif node.nodeName == "SPAN" and node.className:match(italics) then
		table.insert(output, "//")
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, "//")
	
	elseif node.nodeName == "A" then
		table.insert(output, "[[" .. node:getAttribute "href" .. "|")
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, "]]")
	
	elseif node.nodeName == "OL" then
		for i,v in ipairs(node.childNodes) do
			table.insert(output, "  - ")
			treat(v, output)
		end
		
	elseif node.nodeName == "UL" then
		for i,v in ipairs(node.childNodes) do
			table.insert(output, "  * ")
			treat(v, output)
		end
		
	elseif node.nodeName == "BR" then
		table.insert(output, "\\\\\n")
	
	elseif node.nodeName == "H2" then
		table.insert(output, "===== ")
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, " =====\n\n")
	
	elseif node.nodeName == "H3" then
		table.insert(output, "==== ")
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, " ====\n\n")
	
	elseif node.nodeName == "H4" then
		table.insert(output, "=== ")
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		table.insert(output, " ===\n\n")
	
	elseif node.nodeName == "IMG" then
	
		treatImage(node, output)
	elseif node.nodeName == "SPAN" and node.className:match(emoji) then
		for i,v in ipairs(node.childNodes) do
			treat(v, output)
		end
		
	elseif node.nodeName == "SPAN" and node.className:match(hidden) then
		-- nothing!
		
	else
		print("Unhandled node", node.nodeName)
		print(node)
	end
	
end

function saveImage(data, path)
	
	local format,data = data:match("data:image/(%w-);base64,(.*)")
	
	local blob = b64.decode(data)
	
	local finalPath = path .. "." .. format
	
	local fp = io.open("img/" .. finalPath, "wb")
	fp:write(blob)
	fp:close()
	
	return finalPath
end

local imgCount = 0
function treatImage(node, out)
	
	imgCount = imgCount + 1
	
	local data = node:getAttribute "src"
	local path = saveImage(data, pageUrl .. "-" .. imgCount)
	
	table.insert(out, "{{ " .. namespace .. ":" .. path .. " }}")
end

function extractImage(number, src, path)
	local data = src:match("%-%-savepage%-url%-" .. number .. ": url%((.-%))")

	return saveImage(data, path)
end

function getBanner(root, src)
	
	local elem = root:getElementsByClassName(banner)[1]
	if not elem then
		return
	end
	
	local ref = elem:getAttribute "style":match("%-%-savepage%-url%-(%w*)")
	
	return extractImage(ref, src, pageUrl .. "-banner")
end

local months = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"}
for i,v in ipairs(months) do
	months[v] = i
end

function treatDocument(path)
	
	imgCount = 0
	local src = io.open(path, "r"):read "a"

	src = src:match('<!%-%-savepage%-srcdoc%-begin%-%->(.*)<!%-%-savepage%-srcdoc%-end%-%->')

	src = src:gsub("&quot;", '"')
	src = src:gsub("&amp;", '&')
	src = src:gsub("&lt;", '<')
	src = src:gsub("&gt;", '>')
	src = src:gsub("&apos;", "'")

	local body = src:match('<body.*</body>')

	local root,err = hp.parse(body)

	if not root then
		error(err)
	end
	
	local out = {}
		
	-- Get title

	local titleElem = root:getElementsByClassName(title)[1]
	local title = titleElem.textContent
	table.insert(out, "====== " .. title .. " ======\n\n")
	
		-- Double dashes and final dashes break dokuwiki for some reason
	local url = title:lower():gsub("[^%w ]", ""):gsub(" ", "-")
	
	url = url:gsub("%-+", "-"):gsub("%-$", "")
	
	-- Get date
	
	local date = root:getElementsByClassName(date)[1].textContent
	local month, day, year = date:match("(%w+) (%d+), (%d+)")
	local isoDate = string.format("%04d-%02d-%02d", tonumber(year), months[month], tonumber(day))
	
	-- Final URL
	
	pageUrl = isoDate .. "-" .. url
	print(" " .. pageUrl)

	-- Banner
	
	local bannerPath = getBanner(root, src)
	if bannerPath then
		table.insert(out, "{{ " .. namespace .. ":" .. bannerPath .. " }}\n\n")
	end
	
	-- Body

	local mainDoc = root:getElementsByClassName(docBody)[1]

	treat(mainDoc, out)
	
	local fp = io.open("pages/" .. pageUrl .. ".txt", "w")
	fp:write(table.concat(out))
	fp:close()
end

do
	local args = {...}

	for i,v in ipairs(args) do
		print(i,v)
		treatDocument(v)
	end
end