package me.hammerle.code;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Stack;
import java.util.TreeMap;
import me.hammerle.exceptions.CodeTooLongException;
import me.hammerle.exceptions.GotoLabelNotFoundException;
import me.hammerle.exceptions.HoldCodeException;
import me.hammerle.exceptions.PreScriptException;
import me.hammerle.math.Fraction;

public class Script 
{
    private final SnuviParser parser;
    protected final boolean receiveEventBroadcast;
    protected final ArrayList<String> eventVars;
    
    private final int id;
    private final String name;  

    private final HashMap<String, Object> variables;    
    private final HashMap<String, Integer> gotos;
    private final HashSet<String> events;
    private final Stack<Object> valueStack;
    private final Stack<Object> functionStack;
    private final Stack<Integer> returnStack;
    private final TreeMap<Integer, Fraction> forMap;
    
    private Code[] code;
    private int position;

    private int loopCounter;
    
    // halt is only used by waitfor, the script does not react to events if halted
    private boolean halt;
    private boolean isRunning;
    private boolean valid;
    
    private int tryJumpLine;
    
    public Script(SnuviParser parser, int id, String name, String code, boolean receiveEventBroadcast)
    {       
        this.eventVars = new ArrayList<>();
        this.receiveEventBroadcast = receiveEventBroadcast;
        this.parser = parser;
        this.id = id;
        this.name = name;
        
        variables = new HashMap<>();
        gotos = new HashMap<>();
        events = new HashSet<>();
        valueStack = new Stack<>();
        functionStack = new Stack<>();
        returnStack = new Stack<>();
        forMap = new TreeMap<>();
        
        this.code = Code.generate(parser, name, code, gotos);
        if(this.code.length == 0)
        {
            throw new PreScriptException(name, 0, "empty file");
        }
        
        position = 0;

        loopCounter = 0;
        
        halt = false;
        isRunning = false;
        valid = true;
        
        tryJumpLine = -1;
    }
    
    public Script(SnuviParser parser, int id, String name, String code)
    {       
        this(parser, id, name, code, true);
    }
    
    protected void initExpansion(Object... o)
    {
        
    }
    
    public void overload(String code)
    {       
        gotos.clear();
        valueStack.clear();
        functionStack.clear();
        returnStack.clear();
        forMap.clear();
        this.code = Code.generate(parser, name, code, gotos);
        position = -1;
        halt = false;
        valid = true;
        tryJumpLine = -1;
    }
    
    public Code[] getCode(int line)
    {
        line = code[line].realLine;
        int start = 0;
        int end = code.length;
        int helper;

        while(end - start > 1)
        {
            helper = (start + end) >> 1;
            if(code[helper].realLine > line)
            {
                end = helper;
            }
            else if(code[helper].realLine <= line)
            {
                start = helper;
            }
        }
        int realEnd = start;
        start = 0;
        end = code.length;
        while(end - start > 1)
        {
            helper = (start + end) >> 1;
            if(code[helper].realLine >= line)
            {
                end = helper;
            }
            else if(code[helper].realLine < line)
            {
                start = helper;
            }
        }
        return Arrays.copyOfRange(code, end, realEnd + 1);
    }
    
    // -----------------------------------------------------------------------------------
    // Script-Daten
    // -----------------------------------------------------------------------------------
    
    public ISnuviLogger getLogger()
    {
        return parser.logger;
    }
    
    public int getId() 
    {
        return id;
    }

    public String getName() 
    {
        return name;
    }
    
    public boolean isHalt() 
    {
        return halt;
    }
    
    public void setHalt(boolean b) 
    {
        halt = b;
    }
    
    public boolean isRunning() 
    {
        return isRunning;
    }
    
    public boolean isValid() 
    {
        return valid;
    }
    
    public void setInvalid() 
    {
        valid = false;
    }
    
    public int getActiveRealCodeLine()
    {
        if(position < 0 || position >= code.length)
        {
            return 0;
        }
        return code[position].realLine;
    }
    
    // -----------------------------------------------------------------------------------
    // Event-Handling
    // -----------------------------------------------------------------------------------
    
    public void loadEvent(String s)
    {
        events.add(s);
    }
    
    public boolean isLoadedEvent(String s)
    {
        return events.contains(s);
    }
    
    public void unloadEvent(String s)
    {
        events.remove(s);
    }
    
    // -----------------------------------------------------------------------------------
    // Script-Flow
    // -----------------------------------------------------------------------------------
    
    public void onTerm()
    {
    }
    
    public void runCode() 
    {
        if(this.isValid())
        {
            try
            {
                isRunning = true;
                while(position < code.length)
                {
                    code[position].executeFunction(parser, this, valueStack);
                    position++;
                }
                isRunning = false;
                parser.termSafe(this);
            }
            catch(Exception ex)
            {
                isRunning = false;
                if(ex.getClass() != HoldCodeException.class)
                {
                    parser.logger.printException(ex, code[position].function, this, getActiveRealCodeLine());
                }
                position++;
            }
        }
    }
    
    // -----------------------------------------------------------------------------------
    // Variablen
    // -----------------------------------------------------------------------------------
    
    public void setEventVar(String var, Object value)
    {
        variables.put(var, value);   
        eventVars.add(var);
    }
    
    public void setVar(String var, Object value)
    {
        variables.put(var, value);   
    }
    
    public Object getVar(String var)
    {
        return variables.get(var);
    }
    
    public HashMap<String, Object> getVars()
    {
        return variables;
    }
    
    public boolean getBooleanVar(String var)
    {
        try
        {
            return (boolean) getVar(var);
        }
        catch(ClassCastException | NullPointerException ex)
        {
            return false;
        }
    }
    
    public void removeVar(String var)
    {
        variables.remove(var);
    }
    
    // -----------------------------------------------------------------------------------
    // Goto, Return
    // -----------------------------------------------------------------------------------
    
    public void incLoopCounter()
    {
        loopCounter++;
        if(loopCounter > 50)
        {
            resetLoopCounter();
            throw new CodeTooLongException();
        }
    }
    
    public void gotoLabel(String label, boolean scheduled, boolean resetFor)
    {
        Integer i = gotos.get(label);
        if(i == null)
        {
            throw new GotoLabelNotFoundException(label);
        }
        if(resetFor)
        {
            forMap.clear();
        }
        incLoopCounter();
        position = i - (scheduled ? 0 : 1);
    }  
    
    public void resetLoopCounter()
    {
        loopCounter = 0;
    }
    
    public void gotoLabelWithReturn(String label)
    {
        returnStack.push(position);
        gotoLabel(label, false, false);
    }
    
    public void doReturn()
    {
        position = returnStack.pop(); 
    }
    
    public void jump()
    {
        position += (int) code[position].value;
    }
    
    public void jumpDoElse()
    {
        position += (int) code[position].value;
        if(code.length <= position + 1)
        {
            return;
        }
        if("else".equals(code[position + 1].function))
        {
            position++;
        }
    }
    
    // -----------------------------------------------------------------------------------
    // try
    // -----------------------------------------------------------------------------------
    
    public void gotoTryJumpLine()
    {
        position = tryJumpLine; 
    }
    
    public void saveTryJumpLine()
    {
        tryJumpLine = position + ((int) code[position].value) + 1;
        if(!"catch".equals(code[tryJumpLine].function))
        {
            throw new IllegalStateException("try without catch");
        }
    }
    
    public void resetTryJumpLine()
    {
        tryJumpLine = -1;
    }
    
    public int getTryJumpLine()
    {
        return tryJumpLine; 
    }
    
    // -------------------------------------------------------------------------
    // for
    // -------------------------------------------------------------------------
    
    public boolean repeatFinished(Fraction value, Fraction step, Fraction border)
    {
        return (step.isNegative() && border.compareTo(value) > 0) || border.compareTo(value) < 0;
    }
    
    public Fraction nextRepeatData(Fraction start, Fraction step)
    {
        Fraction f = forMap.get(position);
        if(f == null)
        {
            forMap.put(position, start);
            return start;
        }
        f = f.add(step);
        forMap.put(position, f);
        return f;
    }
    
    public void clearRepeatData()
    {
        forMap.remove(position);
    }
    
    public void clearLastRepeatData()
    {
        forMap.pollLastEntry();
    }
    
    // -------------------------------------------------------------------------
    // push, pop stuff for functions
    // -------------------------------------------------------------------------
    
    public void pushFunctionInput(Object[] o)
    {
        for(Object ob : o) 
        {
            valueStack.push(ob);
        }
    }
    
    public void pushFunctionInput(Object[] o, Fraction f)
    {
        pushFunctionInput(o);
        valueStack.push(f);
    }
    
    public Object popFunctionInput()
    {
        return valueStack.pop();
    }
    
    public void push(int start, Object... o)
    {
        for(int i = start; i < o.length; i++)
        {
            functionStack.push(o[i]);
        }
    }
    
    public void pop(Object... o)
    {
        for(int i = o.length - 1; i >= 0; i--)
        {
            setVar(o[i].toString(), functionStack.pop());
        }
    }
}