package com.epam.rd.autocode.bstprettyprint;

public class PrintableTreeInstance implements PrintableTree {

    private TreeNode treeNode;

    @Override
    public void add(int value) {
        TreeNode node = treeNode;
        while (true) {
            if (node == null) {
                treeNode = new TreeNode(value);
                break;
            } else {
                if (node.getValue() < value) {
                    if (node.getLeft() != null) {
                        node = node.getLeft();
                    } else {
                        node.setLeft(new TreeNode(value));
                        break;
                    }
                }
                if (node.getValue() > value) {
                    if (node.getRight() != null) {
                        node = node.getRight();
                    } else {
                        node.setRight(new TreeNode(value));
                        break;
                    }
                }
            }
        }
    }

    @Override
    public String prettyPrint() {
        StringBuilder sb = new StringBuilder();
        traverse(treeNode, treeNode, sb, 0);
        return sb.toString();
    }

    private void traverse(TreeNode node, TreeNode temp, StringBuilder sb, int space) {
        if (node != null) {
            traverse(node.getRight(), node, sb, space + log10(node.getValue()) + 1);

            addSpaces(sb, space);
            addPrePattern(sb, temp, node);
            addPostPattern(sb, node);

            traverse(node.getLeft(), node, sb, space + log10(node.getValue()) + 1);
        }
    }

    private int log10(int n) {
        int ans = 0;

        while (n != 0) {
            ans++;
            n /= 10;
        }

        return ans;
    }

    private void addSpaces(StringBuilder sb, int spaces) {
        for (int i = 0; i < spaces - 1; i++) {
            sb.append(' ');
        }
    }

    private void addPostPattern(StringBuilder sb, TreeNode node) {
        if (node.hasLeft() || node.hasRight()) {
            if (!node.hasLeft()) {
                sb.append('┘');
            }

            if (!node.hasRight()) {
                sb.append('┐');
            }
            if (node.hasRight() && node.hasLeft()) {
                sb.append('┤');
            }
        }
        sb.append("\n");
    }

    private void addPrePattern(StringBuilder sb, TreeNode preNode, TreeNode node) {
        if (preNode.getRight() == node) {
            sb.append('┌');
        }

        if (preNode.getLeft() == node) {
            sb.append('└');
        }

        sb.append(node.getValue());
    }

    private static class TreeNode {
        private final Integer value;
        private TreeNode left;
        private TreeNode right;

        public TreeNode(int value) {
            this.value = value;
        }

        public boolean hasLeft() {
            return this.left != null;
        }

        public boolean hasRight() {
            return this.right != null;
        }

        public Integer getValue() {
            return value;
        }

        public TreeNode getLeft() {
            return left;
        }

        public TreeNode getRight() {
            return right;
        }

        public void setLeft(TreeNode left) {
            this.left = left;
        }

        public void setRight(TreeNode right) {
            this.right = right;
        }
    }
}