jLogin startup

--[[
    Project info:

    Name: jLogin
    Creator: Jesusthekiller
    Language: Lua (CC)
    Website: None
    License: GNU GPL
        License file can be fount at www.jesusthekiller.com/license-gpl.html

    Version: 1.0
]]--

--[[
    Changelog:
      1.0:
        Initial Release
]]--

--[[
    LICENSE:

    jLogin
    Copyright (c) 2013 Jesusthekiller

    This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

    See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program. If not, see <http://www.gnu.org/licenses/>.
]]--

-- Prevent CTRL+T
local oev = os.pullEvent
os.pullEvent = os.pullEventRaw

-- Get sha256 API
if not fs.exists("sha256") then
    assert(http, "HTTP API required to download dependencies!")
    shell.run("pastebin", "get", "8K9hVgXV", "sha256")
end

if not sha256 then
    os.loadAPI("sha256")
end

-- Create command
if not fs.isDir("login") then -- Remove if not dir
    fs.delete("login")
end

if not fs.exists("login") then -- Create dir
    fs.makeDir("login")
end

if not fs.exists("login/login") then -- Download login cmd
    assert(http, "HTTP API required to download dependencies!")
    shell.run("pastebin", "get", "pRan4MNW", "login/login")
end

shell.setPath("/login:"..shell.path()) -- Set path

-- Login screen
term.setBackgroundColor(colors.black)
term.setTextColor(colors.white)
term.clear()
term.setCursorPos(1, 1)

if not fs.exists("login_users") then -- Check for file
    print("No users added! Do login adduser <login> <password>")
    return
end

local f = fs.open("login_users", "r") or os.reboot() -- Open users file
local t = {}

for token in string.gmatch(f.readAll(), "[^\n]+") do -- Users file to table
    table.insert(t, token)
end

f.close()

if #t < 2 or #t % 2 == 1 then -- Check for corrupted file
    fs.delete("login_users")
    print("login_users file is empty or corrupted! File deleted!")
    print("Press any key...")
    coroutine.yield()
    os.pullEvent("key")
    os.reboot()
end

local counter = 0

while true do -- Login loop
    term.setBackgroundColor(colors.black)
    term.setTextColor(colors.white)
    term.clear()
    term.setCursorPos(1, 1)

    if counter % 3 == 0 and counter ~= 0 then -- 30s sleep every 3 fails
        print("Exceeded maximum fail count! You have failed "..counter.." times!")
        for i = counter * 5, 1, -1 do
            term.setCursorPos(1, 3)
            term.clearLine()
            write("You have to wait "..i..((i == 1) and " second" or " seconds"))
            sleep(1)
        end

        term.setBackgroundColor(colors.black)
        term.setTextColor(colors.white)
        term.clear()
        term.setCursorPos(1, 1)
    end

    if counter == 0 then
        print("This computer is locked!")
    end

    write("Login: ")
    local login = read():gsub("%s", "") -- Remove white chars

    write("Password: ")
    local password = read(" ") -- Read w/o any characters shown

    local logged

    for i = 1, #t, 2 do -- Check pass
        if t[i]:lower() == login:lower() then
            if t[i+1] == sha256.sha256(password) then
                logged = true
                term.setBackgroundColor(colors.black)
                term.setTextColor(colors.white)
                term.clear()
                term.setCursorPos(1, 1)
                print("Welcome, "..login)
                break
            end
        end
    end

    if logged then
        break
    else
        print("Wrong login and password combo!")
        sleep(1) -- For no brute force
        counter = counter + 1
    end
end

-- Unload APIs
os.unloadAPI("sha256")

-- Restore os.pullEvent
os.pullEvent = oev