local json = require("dkjson")
local http = require("ssl.https")
local lom = require("lxp.lom")

math.randomseed(os.time())

local function read(path)
  local f = assert(io.open(path, "r"))
  local data = f:read("*a")
  f:close()
  data = data:gsub("[\xC0-\xC1\xF5-\xFF]", "?")
  return data
end

local function write(path, lines)
  os.execute("mkdir -p docs")
  local f = io.open(path, "w")
  for _, line in ipairs(lines) do f:write(line, "\n") end
  f:close()
end

local function escape(s)
  return (s or "")
    :gsub("&", "&")
    :gsub("<", "&lt;")
    :gsub(">", "&gt;")
    :gsub('"', "&quot;")
    :gsub("'", "&apos;")
end

local function strip(s) return (s or ""):gsub("<[^>]+>", ""):match("^%s*(.-)%s*$") end

local function getTag(item, name)
  for _, child in ipairs(item) do
    if child.tag == name then return child[1] or "" end
  end
  return ""
end

local function parseItems(tree)
  for _, node in ipairs(tree) do
    if node.tag == "channel" then
      local items = {}
      for _, child in ipairs(node) do
        if child.tag == "item" then table.insert(items, child) end
      end
      return items
    end
  end
  return {}
end

local function getDomain(url)
  local domain = url:match("https?://([^/]+)")
  return domain or "codeberg.org"
end

local function isToday(date_str)
  if not date_str then return false end
  local today = os.date("!%d %b %Y")
  return date_str:find(today, 1, true) ~= nil
end

local sources = json.decode(read("sources.json"))
local current_time = os.date("%H:%M")

local rss_out = {
  '<?xml version="1.0" encoding="utf-8"?>',
  '<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">',
  '<channel>',
  '<title>Paperboy: ' .. current_time .. '</title>',
  '<description>News feeds aggregated from multiple sources</description>',
  '<link>https://moz75.codeberg.page/feeds-aggregator/feeds/docs/newsfeeds.xml</link>',
  '<lastBuildDate>' .. os.date("!%a, %d %b %Y %H:%M:%S GMT") .. '</lastBuildDate>',
  '<atom:link href="https://moz75.codeberg.page/feeds-aggregator/feeds/docs/newsfeeds.xml" rel="self" type="application/rss+xml" />',
}

for _, source in ipairs(sources) do
  local body, code, headers = http.request(source.url)
  if body and body:match("<rss") then
    local ok, parsed = pcall(lom.parse, body)
    if ok and parsed then
      local items = parseItems(parsed)
      for i = 1, math.min(5, #items) do
        local item = items[i]
        local title = getTag(item, "title")
        local link = getTag(item, "link")
        local date = getTag(item, "pubDate")
        if date and isToday(date) and title ~= "" and link ~= "" then
          local domain = getDomain(link)
          table.insert(rss_out, "<item>")
          table.insert(rss_out, "<title>" .. escape(strip(title)) .. "</title>")
          table.insert(rss_out, "<link>" .. escape(link) .. "</link>")
          table.insert(rss_out, "<guid>" .. escape(link) .. "</guid>")
          table.insert(rss_out, "<pubDate>" .. date .. "</pubDate>")
          table.insert(rss_out, "<category>" .. escape(domain) .. "</category>")
          table.insert(rss_out, "</item>")
        end
      end
    end
  end
end

table.insert(rss_out, "</channel>")
table.insert(rss_out, "</rss>")

write("docs/newsfeeds.xml", rss_out)
os.execute("xsltproc docs/newsfeeds.xsl docs/newsfeeds.xml > docs/newsfeeds.html")