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package shz.core.st.triest;

import shz.core.queue.l.JLinkedQueue;
import shz.core.stack.l.LLinkedStack;

import java.util.Collections;
import java.util.function.Function;
import java.util.function.Predicate;

/**
 * 值为long类型的基于单词查找树的符号表
 * 
 * 8+24+2*r(r为chars数组长度)=chars
 * 8+(56+8*r)*n(n为元素个数)+8*r*n*w(w为键的平均长度)
 * 

 * B=56*(n+1)+8*r*n*(w+1)+(2*r+对齐填充)
 */
public class ConcurrentJTrieST extends ConcurrentTrieST {
    /**
     * 8+25+8*r(r为数组长度)+对齐填充=40+8*r
     * 
     * B=56+8*r
     */
    protected static final class Node extends ConcurrentTrieST.Node {
        public long val;

        public Node(int r) {
            super(r);
        }
    }

    protected ConcurrentJTrieST(char[] chars) {
        super(chars);
        root = new Node(chars.length);
    }

    public static ConcurrentJTrieST of(char[] chars) {
        return new ConcurrentJTrieST(chars);
    }

    public final void put(char[] a, long val) {
        acceptWrite(() -> {
            Node x = root;
            for (char c : a) {
                int i = charIndex.idx(c);
                if (x.next[i] == null) x.next[i] = new Node(len);
                x = x.next[i];
            }
            x.val = val;
            x.leaf = true;
        });
    }

    public final Long get(char[] a) {
        return applyRead(() -> {
            Node x = get(root, a, a.length);
            return x == null || !x.leaf ? null : x.val;
        });
    }

    public final Iterable getAll() {
        return applyRead(() -> get(root));
    }

    protected final Iterable get(Node x) {
        JLinkedQueue queue = JLinkedQueue.of();
        LLinkedStack stack = LLinkedStack.of();
        push(stack, x);
        while (stack.size() > 0) {
            Node pop = stack.pop();
            if (pop.leaf) queue.offer(pop.val);
            push(stack, pop);
        }
        return queue.isEmpty() ? Collections.emptyList() : queue;
    }

    private void push(LLinkedStack stack, Node x) {
        if (x.next == null) return;
        for (int i = 0; i < len; ++i) if (x.next[i] != null) stack.push(x.next[i]);
    }

    public final Iterable getByPrefix(char[] prefix) {
        return applyRead(() -> {
            Node x = get(root, prefix, prefix.length);
            if (x == null) return Collections.emptyList();
            return get(x);
        });
    }

    public final Iterable getChars(Predicate predicate, int limit) {
        return applyRead(() -> getChars0(x -> predicate == null || predicate.test(x.val), limit));
    }

    public final Long computeIfAbsent(char[] a, Function func) {
        Long oldVal = get(a);
        if (oldVal != null) return oldVal;
        return applyWrite(() -> {
            Node x = get(root, a, a.length);
            if (x != null && x.leaf) return x.val;
            Long val = func.apply(a);
            put(a, val);
            return val;
        });
    }
}