GraviDB

-- GraviDB API for databases
-- Free to use by everybody

-- Variables
local standardPath = "databases"

-- Functions

---- dbExists() returns true if database exists.
function dbExists(dbName)
    if (fs.isDir(standardPath .. "/" .. dbName)) then
        return true
    else
        return false
    end
end

---- tblExists() returns true if table in database exists.
function tblExists(dbName, tblName)
    if(dbExists(dbName)) then
        if (fs.isDir(standardPath .. "/" .. dbName .. "/" .. tblName)) then
            return true
        else
            return false
        end
    else
        print("[ERROR] Invalid DB Name.")
        return false
    end
end

---- createDB() creates a database with the supplied name.
function createDB(dbName)
    if(not fs.isDir(standardPath)) then
        fs.makeDir(standardPath)
    end

    if(not dbExists(dbName)) then
        fs.makeDir(standardPath .. "/" .. dbName)
    else
        print("[ERROR] Database already exists.")
    end
end

---- deleteDB() deletes the supplied database
function deleteDB(dbName)
    if(dbExists(dbName)) then
       fs.delete(standardPath .. "/" .. dbName)
    end
end

---- createTbl() creates a new table with the supplied name, inside the supplied database
function createTbl(dbName, tblName)
    if(dbExists(dbName)) then
        if(not tblExists(dbName, tblName)) then
            fs.makeDir(standardPath .. "/" .. dbName .. "/" .. tblName)
        else
            print("[ERROR] Table already exists.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end

---- renameTbl() renames an already existing table to the new supplied name in the supplied database
function renameTbl(dbName, oldTblName, newTblName)
    if(dbExists(dbName)) then
        if(tblExists(dbName, oldTblName)) then
            if(not tblExists(dbName, newTblName)) then
                fs.move(standardPath .. "/" .. dbName .. "/" .. oldTblName, standardPath .. "/" .. dbName "/" .. newTblName)
            else
                print("[ERROR] Table with new name already exists.")
            end
        else
            print("[Error] Invalid old DB Name.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end

---- deleteTbl() removes an already existing table within the supplied database
function deleteTbl(dbName, tblName)
    if(dbExists(dbName)) then
        if(tblExists(dbName, tblName)) then
            fs.delete(standardPath .. "/" .. dbName .. "/" ..tblName)
        else
            print("[ERROR] Invalid Table Name.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end

---- getEntries() returns the amount of keys in the supplied table in the supplied database
function getEntries(dbName, tblName)
    if(dbExists(dbName)) then
        if(tblExists(dbName, tblName)) then
            keys = fs.list(standardPath .. "/" .. dbName .. "/" .. tblName)
            entries = 0

            for i in pairs(keys) do entries = entries + 1 end
            return entries
        else
            print("[ERROR] Invalid Table Name.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end

---- set() sets the value of the supplied key, in the supplied table, in the supplied database
function set(dbName, tblName, id, key, value)
    if(dbExists(dbName)) then
        if(tblExists(dbName, tblName)) then
            if(not fs.isDir(standardPath .. "/" .. dbName .. "/" .. tblName .. "/" .. id)) then
                fs.makeDir(standardPath .. "/" .. dbName .. "/" .. tblName .. "/" .. id)
            end

            keyFile = fs.open(standardPath .. "/" .. dbName .. "/" .. tblName .. "/" .. id .. "/" .. key, "w")
            keyFile.write(value)
            keyFile.close()
        else
            print("[ERROR] Invalid Table Name.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end

---- get() returns the value of the requested key
function get(dbName, tblName, id, key)
    if(dbExists(dbName)) then
        if(tblExists(dbName, tblName)) then
            path = standardPath .. "/" .. dbName .. "/" .. tblName .. "/" .. id .. "/" .. key
            if(fs.exists(path)) then
                keyFile = fs.open(path, "r")
                value = keyFile.readAll()
                keyFile.close()
                return value
            else
                return nil
            end
        else
            print("[ERROR] Invalid Table Name.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end

---- delete() deletes the supplied id.
function delete(dbName, tblName, id)
    if(dbExists(dbName)) then
        if(tblExists(dbName, tblName)) then
            path = standardPath .. "/" .. dbName .. "/" .. tblName "/" .. id
            if(fs.exists(path)) then
                fs.delete(path)
            end
        else
            print("[ERROR] Invalid Table Name.")
        end
    else
        print("[ERROR] Invalid DB Name.")
    end
end