package cfg;

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

import java.util.ArrayList;
import java.util.Arrays;

public class ControlFlowGraph {

    private VFunction f;                // the function represented by this CFG
    private ArrayList<CFGNode> nodes;

    public ControlFlowGraph(VFunction f) {
        this.f = f;
        this.nodes = new ArrayList<>();
    }

    public String getFunction() {
        return this.f.ident;
    }

    public 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;
    }

    public 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 the next node for %s",
                                               a.toString()));

        return ret;

    }

    public void addNode(CFGNode n) {
        MinimalLogger.info(String.format("Node + %s",
                                         n.toString()));
        this.nodes.add(n);
    }

    public String addEdge(CFGNode source, CFGNode dest) {
        /**
         * Iff the CFGNodes are different, construct an edge between them.
         * All variables reaching the parent also reach the children.
         *
         * Returns a string capable of being manipulated by graphviz.
         */
        String ret = "";
        if (!source.equals(dest)) {
            ret = String.format("%s -> %s",
                                source.toString(),
                                dest.toString());
            MinimalLogger.info(String.format("Edge %s",
                                             ret));

            source.addDest(dest);
            dest.addSource(source);

            ret += ";";
        } else {
            MinimalLogger.info(String.format("Skipping duplicate edge for %s",
                                             source.toString()));
        }

        return ret;
    }

    public void addReaching(CFGNode n, String s) {
        MinimalLogger.info(String.format("Def \"%s\" at %s",
                                         s,
                                         n.toString()));
        n.reaching.add(s);
    }

    public void addLiveness(CFGNode n, String s) {
        if (this.isKnownVar(s)) {
            MinimalLogger.info(String.format("Use \"%s\" at %s",
                                             s,
                                             n.toString()));
            n.liveness.add(s);
        } else
            MinimalLogger.info(String.format("Use \"%s\" not a known variable!",
                                             s));
    }

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

    protected boolean isKnownVar(String str) {
        /**
         * Returns true if the variable belongs to the current function.
         * Required when matching liveness in certain instructions.
         *
         * Helper for addLivenessi
         */
        return Arrays.asList(f.vars).contains(str) ||
            Arrays.asList(f.params).contains(str);
    }

}