#include "editor.hpp"

// Treap representation of a file
line* root;

// Get size uf a subtreap
count_type treap::get_size(line* l) {
	if(l == nullptr) return 0;
	return l->size;
}

// Split treap by k-th element
two_lines treap::split(line *l, count_type k) {
	if(l == nullptr) return {nullptr, nullptr};

	if(get_size(l->left) >= k) {
		// In the left subtree
		auto two = split(l->left, k);
		l->left = two.second;
		l->size -= get_size(two.first);
		return {two.first, l};
	}
	else {
		// In the right subtree
		auto two = split(l->right, k - (1+get_size(l->left)));
		l->right = two.first;
		l->size -= get_size(two.second);
		return {l, two.second};
	}
}

// Join two treaps
line* treap::join(line *a, line *b) {
	if(a == nullptr) return b;
	if(b == nullptr) return a;

	if(a->priority < b->priority) {
		a->size += get_size(b);
		a->right = join(a->right, b);
		return a;
	}
	else {
		b->size += get_size(a);
		b->left = join(a, b->left);
		return b;
	}
}

// Find k-th line of file
line* treap::find(line* l, count_type k) {
	if(l == nullptr) return nullptr;

	if(k <= get_size(l->left))
		return find(l->left, k);
	else if(k == get_size(l->left)+1)
		return l;
	else
		return find(l->right, k - (1+get_size(l->left)) );
}

// File access
line* treap::find(count_type k) {
	if(k >= root->size)
		return nullptr;
	// Don't find index k, but k-th line -> +1
	return find(root, k+1);
}
void treap::clear() {
	while(size() > 0) {
		auto two = split(root, 1);
		root = two.second;
		delete two.first;
	}
}

// Line insert
void treap::insert(count_type k, string s) {
	line *l = new line(rand(), s);

	if(root == nullptr) {
		root = l;
		return;
	}

	auto two = split(root, k);
	two.first = join(two.first, l);
	root = join(two);
}
// Line removal
void treap::remove(count_type k) {
	auto two = split(root, k+1);
	auto first_split = split(two.first, k);
	delete first_split.second;
	two.first = first_split.first;
	root = join(two);
}