[GraviBank] database

rednet.open("top")

local requestTypes = {"userExists", "checkPassword", "getBalance", "getLoan"}

local postTypes = {"newUser", "newPassword", "removeUser", "changeBalance", "changeLoan"}

local dbDir = "disk/database.txt"

function readTable(dir)
    local file = fs.open(dir, "r")
    local data = file.readAll()
    file.close()
    return textutils.unserialize(data)
end

function saveTable(table, dir)
    local file = fs.open(dir, "w")
    file.write(textutils.serialize(table))
    file.close()
end

if not fs.exists(dbDir) then
    saveTable({}, dbDir)
end

function handleRequests(data)
    local requestType = "false_request"
    for i, type in pairs(requestTypes) do
        if type == data[1] then
            requestType = type
        end
    end

    if requestType == "false_request" then
        print("false_request TRUE")
        return "false_request"
    end

    if requestType == "userExists" then
        local db = readTable(dbDir)
        if db[data[2]] then
            print("userExists TRUE")
            return "true"
        else
            print("userExists FALSE")
            return "false"
        end


    elseif requestType == "checkPassword" then
        local db = readTable(dbDir)

        if db[data[2]] then
            if db[data[2]].password == data[3] then
                print("checkPassword TRUE")
                return "true"
            else
                print("checkPassword FALSE")
                return "false"
            end
        else
            print("checkPassword FALSE")
            return "false"
        end

    elseif requestType == "getBalance" then
        local db = readTable(dbDir)

        if db[data[2]] then
            print("getBalance TRUE")
            return db[data[2]].bal
        else
            print("getBalance FALSE")
            return "false"
        end

    elseif requestType == "getLoan" then
        local db = readTable(dbDir)

        if db[data[2]] then
            print("getLoan TRUE")
            return db[data[2]].loan
        else
            print("getLoan FALSE")
            return "false"
        end
    end
end

function handlePosts(data)
    local postType = "false_post"
    for i, type in pairs(postTypes) do
        if type == data[1] then
            postType = type
        end
    end

    if requestType == "false_post" then
        print("false_post TRUE")
        return "false_post"
    end

    if postType == "newUser" then
        local db = readTable(dbDir)
        local exists = handleRequests({"userExists", data[2]})

        if exists == "true" then
            print("newUser FALSE")
            return "false"
        else
            if data[3] ~= "" then
                db[data[2]] = {}
                db[data[2]].password = data[3]
                db[data[2]].bal = 0
                db[data[2]].loan = 0
                saveTable(db, dbDir)
                print("newUser TRUE")
                return "true"
            end
        end

    elseif postType == "removeUser" then
        local db = readTable(dbDir)
        local exists = handleRequests({"userExists", data[2]})

        if exists == "true" then
            db[data[2]] = nil
            saveTable(db, dbDir)
            print("removeUser TRUE")
            return "true"
        else
            print("removeUser FALSE")
            return "false"
        end

    elseif postType == "newPassword" then
        local db = readTable(dbDir)
        local exists = handleRequests({"userExists", data[2]})

        if exists == "true" then
            db[data[2]].password = data[3]
            saveTable(db, dbDir)
            print("newPassword TRUE")
            return "true"
        else
            print("newPassword FALSE")
            return "false"
        end

    elseif postType == "changeBalance" then
        local db = readTable(dbDir)
        local exists = handleRequests({"userExists", data[2]})

        if exists == "true" then
            db[data[2]].bal = db[data[2]].bal + data[3]
            saveTable(db, dbDir)
            print("changeBalance TRUE")
            return "true"
        else
            print("changeBalance FALSE")
            return "false"
        end

    elseif postType == "changeLoan" then
        local db = readTable(dbDir)
        local exists = handleRequests({"userExists", data[2]})

        if exists == "true" then
            db[data[2]].loan = db[data[2]].loan + data[3]
            saveTable(db, dbDir)
            print("changeLoan TRUE")
            return "true"
        else
            print("changeLoan FALSE")
            return "false"
        end
    end
end

while true do
    local senderID, receivedMessage = rednet.receive("graviBank")
    if type(receivedMessage) ~= "table" then
        print("isTable FALSE")
        rednet.send(senderID, {"unrecognized_datatype"}, "graviBank")
    else
        if receivedMessage[1] == "request" then
            rednet.send(senderID, {handleRequests(receivedMessage[2])}, "graviBank")
        elseif receivedMessage[1] == "post" then
            rednet.send(senderID, {handlePosts(receivedMessage[2])}, "graviBank")
        else
            print("isCorrectMessagetype FALSE")
            rednet.send(senderID, {"unrecognized_messagetype"}, "graviBank")
        end
    end
end