#!/usr/bin/env lua

local version = 'v0.8.5'
local socket = require("socket")
local urlparser = require("socket.url")
local separator = '- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -\n'
local valid_types = {'0', '1', 'i'}
session = { tabs = {  } }
local save_file_location = string.format('%s/.stubbfaves', assert(os.getenv('HOME'), 'Unable to get home directory'))


function string.split(str, sep)
  assert(str and sep, 'sting.split requires both an input string and a field separator string')
  local start = 1
  local t = {}
  while true do
    local out
    local point = string.find(str, sep, start)
    if point == start then
      out = ''
    elseif not point then
      out = string.sub(str, start)
    else
      out = string.sub(str, start, point - 1)
    end
    table.insert(t, out)
    start = point and point + 1 or nil
    if not start then
      break
    end
  end
  return t
end


function table.out(t)
  for i, v in ipairs(t) do
    print(string.format('%q', v))
  end
end


table.has = function(t, item)
  for i, v in pairs(t) do
    if v == item then
      return true
    end
  end

  return false
end


table.truncate = function(t, i)
  while t[i] do
    table.remove(t, i)
  end
end


--based on:
--https://stackoverflow.com/questions/9013290/lua-socket-client/9014261#9014261
function request_gopher(host, port, query)
  local tcp = assert(socket.tcp())
  local response = {}

  tcp:settimeout(4, 't')
  local connection = tcp:connect(host, port);
  local request
  if connection then
    request = tcp:send(query.."\n");
  end

  if request then
    while true do
      local s, status, partial = tcp:receive()
      if status == "closed" then break end
      if s ~= '.' then
        table.insert(response, (s or partial))
      end
    end
    tcp:close()
  elseif connection then
    response[1] = 'iConnection error. Bad request.'
    tcp:close()
  else
    response[1] = 'iConnection error. Bad host.'
  end

  return response
end


function display_gophermap_row(row)
  local t = session.tabs[session.current_tab]
  local val = string.split(row, '\t')
  local gophertype = string.sub(val[1], 1, 1)
  local text = string.sub(val[1], 2)
  local spacer = '              '
  if gophertype == 'i' then
    print(spacer..text)
  elseif table.has(valid_types, gophertype) then
    local leader = gophertype == '0' and 'TXT' or 'MAP'
    local url = string.format('%s:%s/%s%s', val[3] or '', val[4] or '', gophertype, val[2] or '/')
    table.insert(t.current_links, url)
    local linknum = string.format('(%d)', #t.current_links)
    print(string.format(' %s %5s    %s', leader, linknum, text))
  end
end


function getch()
  -- taken from: http://lua.2524044.n2.nabble.com/How-to-get-one-keystroke-without-hitting-Enter-td5858614.html
  os.execute("stty cbreak </dev/tty >/dev/tty 2>&1")
  local key = io.read(1)
  os.execute("stty -cbreak </dev/tty >/dev/tty 2>&1");
  print('\27[1D ')
  return(key);
end


function mainloop()
  local th = session.tabs[session.current_tab].history
  print('\n')
  while true do
    local bar = string.format('\27[7m    o--[ S t u b b ]-->     (H)elp, (Q)uit       TAB:%d/%d   HST: %d/%d  \27[0m', session.current_tab, #session.tabs,th.loc, #th.items)
    print(bar)
    -- print('\27[7m (G)o to url, (B)ack, (V)isit link, (Q)uit \27[0m')
    local key = string.lower(getch())
    if key == 'q' then
      save_favorites()
      os.exit(0)
    elseif key == 'h' then
      print_help()
    elseif key == 's' then
      save_file()
    elseif key == 'b' then
      back()
    elseif key == 'f' then
      forward()
    elseif key == 'u' then
      update_favorite()
    elseif key == 'r' then
      refresh()
    elseif key == 'a' then
      io.write('Add: (B)ookmark, (T)ab')
      local subkey = string.lower(getch())
      if subkey == 'b' then
        add_favorite()
      elseif subkey == 't' then
        new_tab()
      end
    elseif key == 'l' then
      io.write('List: (B)ookmarks, (T)abs')
      local subkey = string.lower(getch())
      if subkey == 'b' then
        show_favorites()
      elseif subkey == 't' then
        show_tabs()
      end
    elseif key == 'd' then
      io.write('Delete: (B)ookmark, (T)ab')
      local subkey = string.lower(getch())
      if subkey == 'b' then
        remove_favorite()
      elseif subkey == 't' then
        remove_tab()
      end
    elseif key == 'g' then
      io.write('Go to: (B)ookmark, (L)ink, (T)ab, (U)rl')
      local subkey = string.lower(getch())
      if subkey == 'b' then
        visit_link(true)
      elseif subkey == 'l' then
        visit_link()
      elseif subkey == 't' then
        io.write('Enter tab id (! to cancel): ')
        local t = io.read()
        local tabid = tonumber(t)
        if t ~= '!' and tabid and session.tabs[tabid] then
          session.current_tab = tabid
          refresh()
        else
          local x = tabid and print('Invalid tab id') or print('Cancelled')
        end
      elseif subkey == 'u' then
        io.write('Enter gopher url (! to cancel): ')
        local url = io.read()
        if url ~= '!' and url ~= '' then
          go_to_url(url, true)
        else
          print('\n')
        end
      end
    end
  end
end


function refresh()
  local th = session.tabs[session.current_tab].history
  if th.loc > 0 then
    go_to_url(th.items[th.loc])
  end
end


function add_favorite()
  local th = session.tabs[session.current_tab].history
  if #session.history.items == 0 then return false end
  local title
  repeat
    io.write('Enter title for bookmark (! to cancel): ')
    title = io.read()
  until title
  if title == '!' then return print('Cancelled') end
  table.insert(session.favorites,{display = title, link = th.items[th.loc]})
  print('Bookmark added')
  save_favorites()
end


function update_favorite()
  local title
  io.write('Enter the bookmark id (! to cancel): ')
  local favid = io.read()
  if favid == '!' then return print('Cancelled') end
  local id = tonumber(favid) or tonumber(string.sub(favid,2))
  if id then
    local item = session.favorites[id]
    if item then
      print(string.format('Old title: %s', item.display))
      while not title or title == '' do
        io.write('Enter new title (! to cancel) > ')
        title = io.read()
        if title == '!' then return print('Cancelled') end
      end
      item.display = title
      print('Bookmark has been updated')
      save_favorites()
    else
      print('Invalid bookmark id')
    end
  else
    print('Invalid bookmark id')
  end
end


function remove_favorite()
  io.write('Enter the bookmark id to remove (! to cancel): ')
  local favid = io.read()
  if favid == '!' then return print('Cancelled') end
  local id = tonumber(favid) or tonumber(string.sub(favid,2))
  if id then
    local item = session.favorites[id]
    if item then
      table.remove(session.favorites, id)
      print('Bookmark has been removed')
      save_favorites()
    else
      print('Invalid bookmark id')
    end
  else
    print('Invalid bookmark id')
  end
end


function remove_tab()
  io.write('Enter the tab id to remove (! to cancel): ')
  local tabid = io.read()
  if tabid == '!' then return print('Cancelled') end
  local id = tonumber(tabid)
  if id then
    local item = session.tabs[id]
    if item then
      table.remove(session.tabs, id)
      print('Tab has been removed')
    else
      print('Invalid tab id')
    end
  else
    print('Invalid tab id')
  end
end


function visit_link(favorite)
  local t = session.tabs[session.current_tab]
  local linkid
  repeat
    io.write('Enter link id (! to cancel): ')
    local inp = io.read()
    if inp == '!' then return print('Cancelled') end
    linkid = tonumber(inp)
    if not linkid and string.sub(inp, 1, 1) == 'f' then
      linkid = tonumber(string.sub(inp, 2))
    end
  until linkid
  local linkurl
  if favorite then
    selection = session.favorites[linkid]
    if selection then
      linkurl = session.favorites[linkid].link
    else
      return print('Invalid bookmark id')
    end
  else
    linkurl = t.current_links[linkid]
  end
  if linkurl then
    table.truncate(t.history.items, t.history.loc + 1)
    go_to_url(linkurl, true)
  else
    local out = string.format('Link id %d does not exist...', linkid)
    print_gopher_error(out)
  end
end


function back()
  local th = session.tabs[session.current_tab].history
  if th.loc > 1 and #th.items > 1 then
    th.loc = th.loc - 1
    go_to_url(th.items[th.loc])
  end
end


function forward()
  local th = session.tabs[session.current_tab].history
  if th.loc < #th.items then
    th.loc = th.loc + 1
    go_to_url(th.items[th.loc])
  end
end


function print_help()
  print(separator)
  print('\nStubb  ' .. version)
  local helpstring = [[

    Stubb is a text based gopher client that only displays and supports gophertypes:
    0 (text)  and  1 (gopher map).  The application is named for the character Stubb
    from Moby Dick known for his imaginative patter and good humor.

    The command bar lists the current tab number, out of how many total tabs. It also lists the current place in history (for the tab you are currently on).

    Commands:

      <Navigation>
        (B)ack
        (F)orward
        (G)o to url
          - (B)ookmark
          - (L)ink
          - (T)ab
          - (U)rl
        (R)eload current address

      <Bookmarks>
        (A)dd
          - (B)ookmark
          - (T)ab
        (D)elete
          - (B)ookmark
          - (T)ab
        (L)ist
          - (B)ookmarks
          - (T)abs
        (U)pdate bookmark title

      <System>
        (H)elp
        (Q)uit Stubb
        (S)ave file to disk

    For more information, source code, or to get a copy:

    http://tildegit.org/sloum/stubb

    Stubb is free, as in freedom, software. Modify it as you see fit, give it to whoever you want. It would be great if you referenced the original or cross linked, but it is not required.

    ]]
  print(helpstring)
end


function print_gopher_error(text)
  print(separator)
  print(text)
end


function save_file()
  local t = session.tabs[session.current_tab]
  if not t.filedata then return print('No file available. Save canceled.') end
  local homedir = assert(os.getenv('HOME'), 'Unable to find home directory')
  io.write('Enter the filename to save as (! to cancel): ' .. homedir .. '/')
  local filename = io.read()
  if filename == '!' or filename == '' then
    return print('Cancelled')
  elseif string.match(filename, '^[%.%w_-]+$') then
    local filepath = homedir .. '/' .. filename
    local f = io.open(filepath, 'w+')
    f:write(table.concat(t.filedata,'\n'))
    f:close()
    print(string.format('File saved as: %s', filepath))
  else
    print('Invalid filename')
  end
end


function go_to_url(u, add2history)
  local url = parse_url(u)
  local t = session.tabs[session.current_tab]
  if not url.host or url.scheme ~= 'gopher' then
    print(separator)
    print('             I n v a l i d   u r l')
  elseif table.has(valid_types, url.gophertype) then
    t.filedata = request_gopher(url.host, url.port, url.path)
    print(separator)
    handle_response(t.filedata, url.gophertype)
    local o = url.scheme .. '://' .. url.host .. ':' .. url.port .. '/' .. url.gophertype .. url.path
    print('\n\n')
    print(o)
    if add2history then
      table.truncate(t.history.items, t.history.loc + 1)
      table.insert(t.history.items, o)
      t.history.loc = t.history.loc + 1
    end
  end
end


function handle_response(res_table, gtype)
  if gtype == '0' or gtype == 0 then
    local o = table.concat(res_table, '\n')
    print(o)
  else
    session.tabs[session.current_tab].current_links = {}
    for i, v in ipairs(res_table) do
      display_gophermap_row(v)
    end
  end
end


-- Modified version of socket.url.parse
-- Sets up defaults and adds parsing of gophertype
function parse_url(u)
  if not string.find(u, '://', 1, true) then
    u = 'gopher://'..u
  end

  local default = {port=70, scheme='gopher'}
  local parsed = urlparser.parse(u, default)
  if not parsed.path then
    parsed.path = '/'
  end
  if string.find(parsed.path, '^/[%d%a]') then
    parsed.gophertype = string.sub(parsed.path, 2, 2)
    parsed.path = string.sub(parsed.path, 3) or '/'
  elseif string.sub(parsed.path, -1) == '/' then
    parsed.gophertype = '1'
  else
    parsed.gophertype = '0'
  end

  return parsed
end


function show_favorites()
  print(separator)
  print('\n >---B O O K M A R K S--->\n\n')
  for i, v in ipairs(session.favorites) do
    print(string.format(' (f%d)  %s', i, v.display))
  end
  print('\n' .. separator)
end


function show_tabs()
  print(separator)
  print('\n       [ T A B S ]\n\n')
  for i, v in ipairs(session.tabs) do
    local u = v.history.items[v.history.loc] or 'Empty tab'
    local t = session.current_tab == i and ' --> ' or '     '
    print(string.format('%s(%d)  %s', t, i, u))
  end
  print('\n' .. separator)
end


function save_favorites()
  local file = io.open(save_file_location, 'w+')
  file:write("session.favorites = {\n")
  for _,v in ipairs(session.favorites) do
    file:write(string.format("  {[%q] = %q, [%q] = %q},\n", 'display', v.display, 'link', v.link))
  end
  file:write("}\n")
  file:close()
end


function file_exists(name)
  local f=io.open(name,"r")
  if f~=nil then io.close(f) return true else return false end
end


function new_tab()
  local t = {
    history = {
      loc=0,
      items={}
    },
    current_links = {},
    favorites={}
  }

  if #session.tabs < 4 then
    table.insert(session.tabs, t)
    session.current_tab = #session.tabs
  end
end


function init()
  new_tab()
  if file_exists(save_file_location) then
    dofile(save_file_location)
  end
  mainloop()
end

-- run the program
init()