package pgdp;

public class Bank {
    private BankAccountList accounts;
    
    public int newAccount(String firstname, String lastname) {
        BankAccount account = new BankAccount(getNextFreeAccountID(), firstname, lastname);
        if (accounts == null)
            accounts = new BankAccountList(account, null);
        else 
            accounts = accounts.insertSorted(account);
        return account.getAccountnumber();
    }
    
    public void removeAccount(int accountnumber) {
        if (accounts != null)
            accounts = accounts.remove(accountnumber);
    }
    
    public Money getBalance(int accountnumber) {
        BankAccount account = getAccount(accountnumber);
        if (account == null)
            return null;
        else
            return account.getBalance();
    }
    
    public boolean depositOrWithdraw(int accountnumber, Money m) {
        BankAccount account = getAccount(accountnumber);
        
        if (account == null)
            return false;
        
        account.addMoney(m);
        return true;
    }
    
    public boolean transfer(int from, int to, Money m) {
        BankAccount fromAcc = getAccount(from);
        BankAccount toAcc = getAccount(to);
        
        if (fromAcc == null || toAcc == null)
            return false;
        
        fromAcc.addMoney(new Money(-m.getCent()));
        toAcc.addMoney(m);
        return true;
    }
    
    private BankAccount getAccount(int accountnumber) {
        if (accounts == null)
            return null;
        return accounts.get(accountnumber);
    }
    
    
    private int getNextFreeAccountID() {
        // In dieser Implementierung soll die erste unbelegte Accountnummer
        // zurückgegeben werden. Alternativ kann man natürlich einfach die
        // des letzte + 1 nehmen oder ähnliches. 
                
        if (accounts == null)
            return 1000001;
        return accounts.getNextFreeID(1000001);
    }
    
    public String toString() {
        if (accounts == null)
            return "";
        return accounts.toString();
    }
    
    private class BankAccountList {
        public BankAccount info;
        public BankAccountList next;
        
        public BankAccountList(BankAccount info, BankAccountList next) {
            this.info = info;
            this.next = next;
        }
        
        /**
         * Fügt den neuen Account korrekt nach Accountnummer sortiert in die 
         * Liste ein. (Das ist nicht nötig, aber spannender)
         * Gibt immer den nächsten Knoten des Vorgängers zurück (normalerweise
         * ist das der Knoten selbst, allerdings könnte auch ein neuer Knoten
         * zuvor eingefügt werden, dann ist dieser der nächste des Vorgängers).
         */
        public BankAccountList insertSorted(BankAccount account) {
            if (account.getAccountnumber() < info.getAccountnumber())
                // für die aufsteigende Sortierung -> neuer Account gehört davor
                return new BankAccountList(account, this);
            else if (next == null) // kein nächster mehr -> hinten anfügen
                next = new BankAccountList(account, null);
            else
                next = next.insertSorted(account);
            
            return this; // sich selbst zurückgeben als nächsten für den Vorgänger
        }
        
        public BankAccountList remove(int accountnumber) {
            if (next == null)
                return this;
            
            if (info.getAccountnumber() == accountnumber) 
                return next; // nächsten zurückgeben, dadurch wird this entfernt
            
            next = next.remove(accountnumber);
            return this; // nichts geändert
        }
        
        /**
         * Gibt den Bank-Account mit der jeweiligen Accountnummer zurück.
         * return null falls nicht existent.
         */
        public BankAccount get(int accountnumber) {
            if (info.getAccountnumber() == accountnumber) 
                return info;
            else if (next != null)
                return next.get(accountnumber);
            else
                return null;
        }
        
        /**
         * Gibt die kleinste unbelegte Accountnummer größere oder gleich startingFrom
         * zurück. Wir nutzen hier aus, dass die Liste sortiert ist.
         */
        public int getNextFreeID(int startingFrom) {
            if (startingFrom <= info.getAccountnumber())
                if (next == null)
                    return info.getAccountnumber()+1;
                else
                    return next.getNextFreeID(info.getAccountnumber()+1);
            else 
                return startingFrom;
        }
        
        public String toString() {
            return info + "\n-> " + (next != null ? next.toString() : "Ende");
        }
    }
    
    public static void main(String[] args) {
        Bank b = new Bank();
        
        int[][] acc = new int[5][2];
        
        acc[0][0] = b.newAccount("Fred", "Feuerstein");
        acc[1][0] = b.newAccount("Torben", "Schröder");
        acc[2][0] = b.newAccount("Lilly", "Potter");
        acc[3][0] = b.newAccount("Ronald", "Peterson");
        acc[4][0] = b.newAccount("Bastian", "Schweinsteiger");
        
        for (int a[] : acc) {
            System.out.print(a[0] + ": " + b.getBalance(a[0]));
            System.out.print("  {" + b.getAccount(a[0]) + "}");
            System.out.println("");
        }
        
        for (int i = 0; i < 5; i++)
            for (int a[] : acc) {
                int add = new java.util.Random().nextInt(20000)-10000;
                int oldBalance = b.getBalance(a[0]).getCent();
                a[1] += add;
                if (!b.depositOrWithdraw(a[0], new Money(add)))
                    System.out.println("Could not deposit... !!!!!!!!!!!!!!!! ATTENTION --- THIS SHOULD NOT HAPPEN --- ATTENTION !!!!!!!!!!!!!");
                System.out.println(a[0] + ": " + oldBalance + " + " + 
                        + add + " -> " + b.getBalance(a[0]));
            }
        
        System.out.println("\n\nCHECK:");
        for (int a[] : acc) {
            System.out.println(a[0] + ": " + b.getBalance(a[0]) + " == " + a[1]
                    + "   ---> " + (b.getBalance(a[0]).getCent() == a[1]));
        }
        
        System.out.println("\n\nAll in list:");
        BankAccountList current = b.accounts;
        while (current != null) {
            System.out.println(" " + current.info);
            current = current.next;
        }
        
        System.out.println("Try remove probably not existing 491203193...");
        b.removeAccount(491203193);
        
        System.out.println("All in list:");
        current = b.accounts;
        while (current != null) {
            System.out.println(" " + current.info);
            current = current.next;
        }
        
        for (int i = 0; i < 8; i++) {
            System.out.println("\n\n");
            
            int fromIndex = new java.util.Random().nextInt(acc.length);
            int toIndex = new java.util.Random().nextInt(acc.length);
            
            int from = acc[fromIndex][0];
            int to = acc[toIndex][0];
            int money = new java.util.Random().nextInt(100);
            
            acc[fromIndex][1] -= money;
            acc[toIndex][1] += money;
            
            System.out.println("Try transfer " + money + " from " + from + " to " + to + " :");
            System.out.println("Deposit " + (b.transfer(from, to, new Money(money)) ? "successful" : "failed (!!!!!!!!!!!!!!!! ATTENTION --- THIS SHOULD NOT HAPPEN --- ATTENTION !!!!!!!!!!!!!)"));
            
            System.out.println("All in list:");
            current = b.accounts;
            while (current != null) {
                System.out.println(" " + current.info);
                current = current.next;
            }
            
            if (i >= 3) {
                System.out.println("Try transfer back " + money + " from " + to + " to " + from + " :");
                System.out.println("Deposit " + (b.transfer(to, from, new Money(money)) ? "successful" : "failed (!!!!!!!!!!!!!!!! ATTENTION --- THIS SHOULD NOT HAPPEN --- ATTENTION !!!!!!!!!!!!!)"));

                acc[fromIndex][1] += money;
                acc[toIndex][1] -= money;

                System.out.println("All in list:");
                current = b.accounts;
                while (current != null) {
                    System.out.println(" " + current.info);
                    current = current.next;
                }
            }
        }
        
        
        System.out.println("\n\nCHECK:");
        for (int a[] : acc) {
            System.out.println(a[0] + ": " + b.getBalance(a[0]) + " == " + a[1]
                    + "   ---> " + (b.getBalance(a[0]).getCent() == a[1]));
        }
        
        
        for (int i = 1; i < acc.length-2; i++) {
            System.out.println("\n\nRemove existing acc " + i + " Nr: " + acc[i][0]);
            b.removeAccount(acc[i][0]);

            System.out.println("Try deposit on " + acc[i][0] + ":");
            System.out.println("Deposit " + (b.depositOrWithdraw(acc[i][0], new Money(10000)) ? "successful (!!!!!!!!!!!!!!!! ATTENTION --- THIS SHOULD NOT HAPPEN --- ATTENTION !!!!!!!!!!!!!)" : "failed"));

            System.out.println("All in list:");
            current = b.accounts;
            while (current != null) {
                System.out.println(" " + current.info);
                current = current.next;
            }

            System.out.println("Try transfer from " + acc[i][0] + " to " + acc[(i+1)][0] + " :");
            System.out.println("Deposit " + (b.transfer(acc[i][0], acc[i+1][0], new Money(7584)) ? "successful (!!!!!!!!!!!!!!!! ATTENTION --- THIS SHOULD NOT HAPPEN --- ATTENTION !!!!!!!!!!!!!)" : "failed"));
            System.out.println("Try transfer from " + acc[i-1][0] + " to " + acc[i][0] + " :");
            System.out.println("Deposit " + (b.transfer(acc[i-1][0], acc[i][0], new Money(9302)) ? "successful (!!!!!!!!!!!!!!!! ATTENTION --- THIS SHOULD NOT HAPPEN --- ATTENTION !!!!!!!!!!!!!)" : "failed"));
  
            
            System.out.println("All in list:");
            current = b.accounts;
            while (current != null) {
                System.out.println(" " + current.info);
                current = current.next;
            }
            
            System.out.println("Try removing " + acc[i][0] + " again.");
            b.removeAccount(acc[i][0]);
            
            System.out.println("All in list:");
            current = b.accounts;
            while (current != null) {
                System.out.println(" " + current.info);
                current = current.next;
            }
            
            
            System.out.println("\n\nCHECK:");
            for (int j = 0; j < acc.length; j++) {
                if (j >= 1 && j <= i) continue;
                System.out.println(acc[j][0] + ": " + b.getBalance(acc[j][0]) + " == " + acc[j][1]
                        + "   ---> " + (b.getBalance(acc[j][0]).getCent() == acc[j][1]));
            }
        }
        
    }
}