package vaporize.library;

import cs132.vapor.ast.*;
import misc.*;

import java.util.ArrayList;

public class ControlFlowGraph {

    private ArrayList<CFGNode> nodes;
    private CFGNode start;

    protected ControlFlowGraph() {
        this.nodes = new ArrayList<>();
        this.start = null;
    }

    protected CFGNode getNode(Object a) {
        CFGNode ret = null;
        for (CFGNode n : this.nodes) {
            if (n.equals(a)) {
                ret = n;
                break;
            }
        }

        if (ret == null) {
            String str = (a instanceof Node) ? ((Node) a).sourcePos.toString() :
                a.toString();
            MinimalLogger.severe(String.format("Could not find a node matching %s",
                                               str));
        }
        return ret;
    }

    protected CFGNode getNextNode(CFGNode a) {
        CFGNode ret = null;
        // we return null if the passed node is the last in the list
        for (int i = 0; i < this.nodes.size()-1; ++i) {
            if (this.nodes.get(i).equals(a)) {
                ret = this.nodes.get(i+1);
                break;
            }
        }

        if (ret == null)
            MinimalLogger.severe(String.format("Could not find a node matching %s",
                                               a.toString()));

        return ret;

    }

    protected void addNode(CFGNode node) {
        this.nodes.add(node);
    }

    protected String addEdge(CFGNode source, CFGNode dest) {
        /**
         * Iff the CFGNodes are different, construct an edge between them.
         * Returns a string capable of being manipulated by graphviz.
         */
        String ret = "";
        if (!source.equals(dest)) {
            ret = String.format("%d -> %d",
                                source.getInstruction().sourcePos.line,
                                dest.getInstruction().sourcePos.line);
            MinimalLogger.info(String.format("Edge %s",
                                             ret));

            source.addDest(dest);
            dest.addSource(source);
            ret += ";";
        } else {
            MinimalLogger.info(String.format("Skipping duplicate edge for %d",
                                             source.getInstruction().sourcePos.line));
        }

        return ret;
    }

    protected void setStart(CFGNode start) {
        this.start = start;
    }

    protected ArrayList<CFGNode> getNodes() {
        return this.nodes;
    }

}