CC-WEB: A Web Browser For ComputerCraft

local tArgs, initialURL = {...}, "http://example.com"
local history, currentPage, scroll, horizontalScroll, cache, bookmarks = {}, 0, 0, 0, {}, {}
local width, height = term.getSize()
local running = true

local function urlEncode(url)
  return url:gsub("([^%w%-%.%_%~])", function(c) return string.format("%%%02X", string.byte(c)) end)
end

local function resolveURL(base, relative)
  if relative:match("^https?://") then return relative end
  if relative:sub(1,1) == "/" then return base:match("^(https?://[^/]+)") .. relative end
  return base:match("^(.*/)") .. relative
end

local function trim(s)
  return s:match("^%s*(.-)%s*$")
end

local function parseCSS(css)
  local styles = {}
  for selector, rules in css:gmatch("([^{]+){([^}]+)}") do
    selector = trim(selector)
    styles[selector] = {}
    for property, value in rules:gmatch("([^:]+):([^;]+);?") do
      styles[selector][trim(property)] = trim(value)
    end
  end
  return styles
end

local colorMap = {
  black = colors.black, red = colors.red, green = colors.green,
  yellow = colors.yellow, blue = colors.blue, purple = colors.purple,
  cyan = colors.cyan, white = colors.white, gray = colors.gray,
  lightGray = colors.lightGray, lime = colors.lime, orange = colors.orange,
}

local function getCCColor(cssColor)
  if colorMap[cssColor] then return colorMap[cssColor]
  elseif cssColor:match("^#%x%x%x$") then
    local r, g, b = cssColor:match("#(%x)(%x)(%x)")
    r, g, b = tonumber(r, 16), tonumber(g, 16), tonumber(b, 16)
    return 2^math.floor(r/8) + 2^(math.floor(g/8)+4) + 2^(math.floor(b/8)+8)
  end
  return colors.white
end

local function parseHTML(html)
  local content = {}
  local stack = {}
  local inStyle = false
  local cssContent = ""

  local function addText(text)
    text = text:gsub(" ", " ")
           :gsub("<", "<")
           :gsub(">", ">")
           :gsub("&", "&")
           :gsub('"', '"')
           :gsub("&#(%d+);", function(n) return string.char(tonumber(n)) end)
    text = text:gsub("^%s+", ""):gsub("%s+$", ""):gsub("%s+", " ")
    if text ~= "" then
      table.insert(content, {type = "text", text = text})
    end
  end

  for tag, text in html:gmatch("(<[^>]+>)([^<]*)") do
    local tagName = tag:match("</?(%w+)")
    if tagName then
      if inStyle then
        if tag:match("^%s*/%s*" .. tagName .. "%s*>") then
          inStyle = false
          table.insert(content, {type = "tag_end", name = tagName})
          table.remove(stack)
        end
      else
        local attrs = {}
        for k, v in tag:gmatch('(%w+)="([^"]*)"') do
          attrs[k] = v
        end
        if tag:match("^<style") then
          inStyle = true
        elseif tag:match("^</") then
          table.insert(content, {type = "tag_end", name = tagName})
          table.remove(stack)
        else
          table.insert(content, {type = "tag_start", name = tagName, attrs = attrs})
          if not tag:match("/>$") then
            table.insert(stack, tagName)
          end
        end
      end
    end
    if inStyle then
      cssContent = cssContent .. text
    else
      addText(text)
    end
  end

  return content, parseCSS(cssContent)
end

local function renderContent(content, styles, width)
  local output = {}
  local line = ""
  local links = {}
  local linkIndex = 1
  local listStack = {}
  local inPre = false
  local currentStyle = {color = colors.white, background = colors.black}
  local styleStack = {}

  local function applyStyle(tag)
    local style = styles[tag] or {}
    if style.color then currentStyle.color = getCCColor(style.color) end
    if style.background then currentStyle.background = getCCColor(style.background) end
    table.insert(styleStack, {color = currentStyle.color, background = currentStyle.background})
  end

  local function removeStyle()
    table.remove(styleStack)
    if #styleStack > 0 then
      currentStyle = styleStack[#styleStack]
    else
      currentStyle = {color = colors.white, background = colors.black}
    end
  end

  local function renderLine()
    if #line > 0 then
      table.insert(output, {text = string.rep(" ", #listStack) .. line, color = currentStyle.color, background = currentStyle.background})
      line = ""
    end
  end

  for _, item in ipairs(content) do
    if item.type == "text" then
      if inPre then
        line = line .. item.text
        if item.text:find("\n") then renderLine() end
      else
        for word in item.text:gmatch("%S+") do
          if #line + #word + 1 > width - 2 * #listStack then renderLine() end
          line = #line == 0 and word or line .. " " .. word
        end
      end
    elseif item.type == "tag_start" then
      applyStyle(item.name)
      if item.name == "br" then
        renderLine()
      elseif item.name:match("^h%d$") then
        renderLine()
        local level = tonumber(item.name:sub(2))
        line = string.rep("#", level) .. " "
      elseif item.name == "p" then
        renderLine()
        table.insert(output, {text = "", color = currentStyle.color, background = currentStyle.background})
      elseif item.name == "ul" or item.name == "ol" then
        renderLine()
        table.insert(listStack, item.name)
      elseif item.name == "li" then
        renderLine()
        line = (listStack[#listStack] == "ul" and "• " or #listStack .. ". ")
      elseif item.name == "a" and item.attrs and item.attrs.href then
        table.insert(links, {url = item.attrs.href, index = linkIndex})
        line = line .. "[" .. linkIndex .. "]"
        currentStyle.color = colors.blue
      elseif item.name == "pre" then
        inPre = true
        renderLine()
      end
    elseif item.type == "tag_end" then
      if item.name == "a" then
        linkIndex = linkIndex + 1
        removeStyle()
      elseif item.name == "p" or item.name:match("^h%d$") then
        renderLine()
        table.insert(output, {text = "", color = currentStyle.color, background = currentStyle.background})
      elseif item.name == "ul" or item.name == "ol" then
        renderLine()
        table.remove(listStack)
      elseif item.name == "pre" then
        inPre = false
        renderLine()
      end
      removeStyle()
    end
  end
  renderLine()
  return output, links
end

local function fetchPage(url)
  if cache[url] then return cache[url] end
  local response = http.get(url)
  if not response then return nil end
  local content = response.readAll()
  response.close()
  cache[url] = content
  return content
end

local buttons = {}

local function createButton(name, x, y, width, height, text, onClick)
  buttons[name] = {x=x, y=y, width=width, height=height, text=text, onClick=onClick}
end

local function drawButton(name)
  local button = buttons[name]
  paintutils.drawFilledBox(button.x, button.y, button.x + button.width - 1, button.y + button.height - 1, colors.lightGray)
  term.setCursorPos(button.x + math.floor((button.width - #button.text) / 2), button.y + math.floor(button.height / 2))
  term.setTextColor(colors.black)
  term.write(button.text)
end

local function checkButtonClick(x, y)
  for name, button in pairs(buttons) do
    if x >= button.x and x < button.x + button.width and y >= button.y and y < button.y + button.height then
      paintutils.drawFilledBox(button.x, button.y, button.x + button.width - 1, button.y + button.height - 1, colors.gray)
      term.setCursorPos(button.x + math.floor((button.width - #button.text) / 2), button.y + math.floor(button.height / 2))
      term.setTextColor(colors.white)
      term.write(button.text)
      sleep(0.1)
      button.onClick()
      return true
    end
  end
  return false
end

local function loadBookmarks()
  if fs.exists("cc_web_bookmarks") then
    local file = fs.open("cc_web_bookmarks", "r")
    for line in file.readLine do
      local name, url = line:match("([^,]+),(.+)")
      if name and url then bookmarks[name] = url end
    end
    file.close()
  end
end

local function saveBookmarks()
  local file = fs.open("cc_web_bookmarks", "w")
  for name, url in pairs(bookmarks) do
    file.writeLine(name .. "," .. url)
  end
  file.close()
end

local function showLoadingScreen()
  term.clear()
  term.setCursorPos(1, 1)

  local logo = [[
   (     (      (  (          (
   )\    )\     )\))(   '(  ( )\
 (((_) (((_)___((_)()\ ) )\ )((_)
 )\___ )\__|___|(())\_)(|(_|(_)_
((/ __((/ __|  \ \((_)/ / __| _ )
 | (__ | (__    \ \/\/ /| _|| _ \
  \___| \___|    \_/\_/ |___|___/
  ]]

  local logoLines = {}
  for line in logo:gmatch("[^\r\n]+") do
    table.insert(logoLines, line)
  end

  local startY = math.floor((height - #logoLines) / 2) - 2
  for i, line in ipairs(logoLines) do
    term.setCursorPos(math.floor((width - #line) / 2), startY + i)
    term.write(line)
  end

  local barWidth = 40
  local barStartX = math.floor((width - barWidth) / 2)
  local barY = startY + #logoLines + 2

  term.setCursorPos(barStartX, barY)
  term.write("[" .. string.rep(" ", barWidth - 2) .. "]")

  local text = "A Web Browser For CC Made by nonogamer9"
  term.setCursorPos(math.floor((width - #text) / 2), barY + 2)
  term.write(text)

  for i = 1, barWidth - 2 do
    term.setCursorPos(barStartX + i, barY)
    term.write("=")
    sleep(5 / (barWidth - 2))
  end
end

local function displayPage(url)
  term.clear()
  term.setCursorPos(1,1)
  term.write("CC-WEB: Loading " .. url .. "...")

  if not url:match("^https?://") then url = "http://" .. url end
  local html = fetchPage(url)
  if not html and url:match("^http://") then
    url = url:gsub("^http://", "https://")
    html = fetchPage(url)
  end
  if not html then
    term.clear()
    term.setCursorPos(1,1)
    term.write("CC-WEB: Error loading page")
    os.sleep(2)
    return
  end

  local content, styles = parseHTML(html)
  local rendered, links = renderContent(content, styles, width - 1)

  local function drawScreen()
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.clear()
    term.setCursorPos(1, 1)
    term.setTextColor(url:match("^https://") and colors.green or colors.red)
    term.write(url:match("^https://") and "[Secure] " or "[Not Secure] ")
    term.setTextColor(colors.white)
    for i = 2, height - 3 do
      local lineIndex = i + scroll - 1
      if lineIndex <= #rendered then
        local line = rendered[lineIndex]
        term.setCursorPos(1, i)
        term.setTextColor(line.color)
        term.setBackgroundColor(line.background)
        local displayText = line.text:sub(horizontalScroll + 1, horizontalScroll + width)
        term.write(displayText)
      end
    end
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.setCursorPos(1, height - 2)
    term.write(string.rep("-", width))
    term.setCursorPos(1, height - 1)
    term.write("URL: " .. url:sub(1, width - 9))
    for _, button in pairs(buttons) do
      drawButton(_)
    end
  end

  createButton("back", width - 27, height, 3, 1, "<", function()
    if currentPage > 1 then
      currentPage = currentPage - 1
      displayPage(history[currentPage])
    end
  end)

  createButton("forward", width - 23, height, 3, 1, ">", function()
    if currentPage < #history then
      currentPage = currentPage + 1
      displayPage(history[currentPage])
    end
  end)

  createButton("reload", width - 19, height, 3, 1, "R", function()
    cache[url] = nil
    displayPage(url)
  end)

  createButton("bookmark", width - 15, height, 3, 1, "B", function()
    term.setCursorPos(1, height)
    term.clearLine()
    term.write("Enter bookmark name: ")
    local name = read()
    if name and #name > 0 then
      bookmarks[name] = url
      saveBookmarks()
    end
  end)

  createButton("toggle", width - 11, height, 3, 1, "T", function()
    local newUrl = url:gsub("^https?://", "")
    newUrl = (url:match("^https://") and "http://" or "https://") .. newUrl
    displayPage(newUrl)
  end)

  createButton("bookmarks", width - 7, height, 3, 1, "L", function()
    term.clear()
    term.setCursorPos(1, 1)
    term.write("Bookmarks:")
    local i = 1
    for name, bUrl in pairs(bookmarks) do
      term.setCursorPos(1, i + 1)
      term.write(i .. ". " .. name .. " - " .. bUrl)
      i = i + 1
    end
    term.setCursorPos(1, height)
    term.write("Enter number to load or 'q' to return: ")
    local input = read()
    if input ~= "q" then
      local num = tonumber(input)
      if num and num <= i - 1 then
        local j = 1
        for _, bUrl in pairs(bookmarks) do
          if j == num then
            displayPage(bUrl)
            return
          end
          j = j + 1
        end
      end
    end
    displayPage(url)
  end)

  createButton("quit", width - 3, height, 3, 1, "Q", function()
    running = false
  end)

  local function handleInput()
    while true do
      drawScreen()
      local event, param, x, y = os.pullEvent()
      if event == "key" then
        if param == keys.up and scroll > 0 then
          scroll = scroll - 1
        elseif param == keys.down and scroll < #rendered - height + 4 then
          scroll = scroll + 1
        elseif param == keys.left and horizontalScroll > 0 then
          horizontalScroll = horizontalScroll - 1
        elseif param == keys.right and horizontalScroll < width then
          horizontalScroll = horizontalScroll + 1
        elseif param == keys.q then
          return "quit"
        end
      elseif event == "mouse_click" and param == 1 then
        if checkButtonClick(x, y) then
          if not running then
            return "quit"
          end
        elseif y == height - 1 and x > 5 and x <= width - 1 then
          term.setCursorPos(6, height - 1)
          term.clearLine()
          term.write(url)
          term.setCursorPos(6, height - 1)
          local input = read(nil, nil, function(text)
            if text == "" then
              return {url}
            else
              return {}
            end
          end)
          if input then
            if not input:match("^https?://") then
              input = "http://" .. input
            end
            table.insert(history, input)
            currentPage = #history
            return displayPage(input)
          end
        elseif y <= height - 3 then
          local clickedLine = rendered[y + scroll - 1]
          if clickedLine then
            local clickedText = clickedLine.text
            local linkNumber = clickedText:match("%[(%d+)%]")
            if linkNumber then
              local clickedLink = links[tonumber(linkNumber)]
              if clickedLink then
                local newURL = resolveURL(url, clickedLink.url)
                table.insert(history, newURL)
                currentPage = #history
                return displayPage(newURL)
              end
            end
          end
        end
      end
    end
  end

  return handleInput()
end

loadBookmarks()
showLoadingScreen()
table.insert(history, initialURL)
currentPage = 1

while running do
  local result = displayPage(history[currentPage])
  if result == "quit" then
    break
  end
end

term.clear()
term.setCursorPos(1,1)
print("Thank you for using CC-WEB Browser!")