DataBase

rednet.host("luabank", "database")
local crypt

local function log(txt)
    local file = fs.open("banklog", "a")
    file.writeLine(txt)
    file.close()

    print(txt)
end

for i,v in pairs(peripheral.getNames()) do
    if peripheral.getType(v) == "cryptographic accelerator" then
        crypt = peripheral.wrap(v)
    elseif peripheral.getType(v) == "modem" then
        rednet.open(v)
    end
end

if not crypt then
    log("Error: Hook up a bloody cryptographic accelerator")
    return
end

term.clear()
term.setCursorPos(1,1)

local sessionKeys = {}
local users = {}

if fs.exists("enckeys") then
    local file = fs.open("enckeys", "r")
    local nkeys = textutils.unserialize(file.readAll())
    for i,v in pairs(nkeys) do
        sessionKeys[i] = {crypt.decodeKey("RSA", v[1]), crypt.decodeKey("AES", v[2])}
    end
    file.close()
end

if fs.exists("users") then
    local file = fs.open("users", "r")
    users = textutils.unserialize(file.readAll())
    file.close()
end

local function saveKeys()
    local nkeys = {}
    for i,v in pairs(sessionKeys) do
        nkeys[i] = {v[1].encode(), v[2].encode()}
    end

    local file = fs.open("enckeys", "w")
    file.write(textutils.serialize(nkeys))
    file.close()
end

local function saveUsers()
    local file = fs.open("users", "w")
    file.write(textutils.serialize(users))
    file.close()
end

local pub, priv
if fs.exists("pbkeys") then
    local file = fs.open("pbkeys", "r")
    pub = crypt.decodeKey("RSA", file.readLine())
    priv = crypt.decodeKey("RSA", file.readLine())
    file.close()
else
    pub, priv = crypt.generateKeyPair("RSA", 1024)
    local file = fs.open("pbkeys", "w")
    file.writeLine(pub.encode())
    file.writeLine(priv.encode())
    file.close()
end

local function generateU()
    local key = ""
    for i = 1, 16 do
        key = key .. string.char(math.random(32, 126))
    end

    return key
end

local function getUserFromCard(card)
    for i,v in pairs(users) do
        for m,c in pairs(v.cards) do
            if c == card then
                return i
            end
        end
    end
end

local function sMsg(id, msg)
    rednet.send(id, sessionKeys[id][2].encrypt("AES/CFB/NoPadding", msg), "luabank")
end

while true do
    local suc, err = pcall(function()
        local id, msg, protocol = rednet.receive("luabank")
        if protocol == "luabank" then
            if msg:sub(1, 5) == "skeys" then
                sessionKeys[id] = {crypt.decodeKey("RSA", msg:sub(6))}
                --saveKeys()
                rednet.send(id, "mkeys" .. pub.encode(), "luabank")
            elseif msg:sub(1, 5) == "tkeys" then
                local dat = priv.decrypt("RSA", msg:sub(6))
                if dat == "start" then
                    sessionKeys[id][2] = crypt.generateSymmetricKey("AES", nil)
                    saveKeys()
                    rednet.send(id, "ykeys" .. sessionKeys[id][2].encode(), "luabank")
                end
            elseif msg:sub(1, 5) == "smsgs" then
                local dat = textutils.unserialize(sessionKeys[id][2].decrypt("AES/CFB/NoPadding", msg:sub(6)))
                if not dat then
                    error("Could not decrypt message")
                end

                if dat[1] == "r" then -- register
                    local username = dat[2]:lower()
                    local password = dat[3]:lower()

                    if users[username] then
                        sMsg(id, "erroruser exists")
                        log("User '" .. username .. "' exists")
                    else
                        users[username] = {cards = {}, money = 0, pass = crypt.hash("SHA256", password)}
                        sMsg(id, "success")
                        sMsg(id, "success")
                        log("Created user '" .. username .. "'")
                        saveUsers()
                    end
                elseif dat[1] == "c" then -- create card
                    local username = dat[2]:lower()
                    local password = dat[3]:lower()

                    if users[username] and users[username].pass == crypt.hash("SHA256", password) then
                        local key = generateU()
                        table.insert(users[username].cards, key)
                        sMsg(id, key)
                        log("Created card for user '" .. username .. "'")
                        saveUsers()
                    else
                        sMsg(id, "errorinvalid")
                    end
                elseif dat[1] == "t" then -- transact
                    local card = dat[2]
                    local rec = dat[3]
                    local am = tonumber(dat[4])

                    local pos = getUserFromCard(card)
                    -- print(rec)
                    if not users[rec] then
                        sMsg(id, "errorrecipient invalid")
                    else
                        if am < 1 then
                            sMsg(id, "errorinvald amount")
                        elseif users[pos].money < am then
                            sMsg(id, "errornot enough money")
                        else
                            users[pos].money = users[pos].money - am
                            users[rec].money = users[rec].money + am
                            saveUsers()
                            print("Transfered " .. am .. " from user '" .. pos .. "' to user '" .. rec .. "'")
                            sMsg(id, "success")
                        end
                    end
                elseif dat[1] == "tu" then
                    local user = dat[2]
                    local pass = dat[3]
                    local rec = getUserFromCard(dat[4])
                    local am = tonumber(dat[5])

                    if users[user] and users[rec] then
                        if users[user].pass == crypt.hash("SHA256", pass) then
                            if am < 1 then --users[user].money < am
                                sMsg(id, "errorinvalid money")
                            else
                                users[rec].money = users[rec].money + am
                                users[user].money = users[user].money - am
                                log("Transfered " .. am .. " from user '" .. user .. "' to user '" .. rec .. "'")
                                sMsg(id, "success")
                            end
                        else
                            sMsg(id,  "errorinvalid password")
                        end
                    else
                        sMsg(id, "errorinvalid user")
                    end
                elseif dat[1] == "tl" then
                    local user = dat[2]
                    local pass = dat[3]
                    local rec = dat[4]
                    local am = tonumber(dat[5])

                    if users[user] and users[rec] then
                        if users[user].pass == crypt.hash("SHA256", pass) then
                            if am < 1 or users[user].money < am then
                                sMsg(id, "errorinvalid money")
                            else
                                users[user].money = users[user].money  - am
                                users[rec].money = users[rec].money + am
                                log("Transfered " .. am .. " from user '" .. user .. "' to user '" .. rec .. "'")
                                sMsg(id, "success")
                            end
                        else
                            sMsg(id, "errorinvalid password")
                        end
                    else
                        sMsg(id, "errorinvalid user")
                    end
                end
            end
        end
    end)

    if not suc then
        log("Error: " .. err)
    end
end