#include "TileList.h"

TileList::TileList()
{
    tiles = new Tile[INITIAL_SIZE];
    cur_size = INITIAL_SIZE;
}

TileList::~TileList()
{
    delete[] tiles;
}

void TileList::addTile(const Tile &tile)
{
    // O(1) (amortized)
    if (amount_tiles == cur_size) {
        // reached size limit, so allocate new array and move the old tiles
        cur_size *= 2;
        Tile *expanded_tiles = new Tile[cur_size];
        for (int i = 0; i < amount_tiles; i++) {
            expanded_tiles[i] = tiles[i];
        }
        delete[] tiles;
        tiles = expanded_tiles;
    }
    tiles[amount_tiles++] = tile;
}

void TileList::drawAll(QGraphicsScene *scene) const
{
    // O(n)
    for (int i = 0; i < amount_tiles; i++) {
        (tiles + i)->draw(scene);
    }
}

int TileList::indexOfTopTile(int x, int y) const
{
    // O(n)
    for (int i = amount_tiles - 1; i >= 0; --i) {
        if ((tiles + i)->contains(x, y)) {
            return i;
        }
    }
    return -1;
}

void TileList::shiftRight(int start, int end)
{
    // e.g. amount_tiles=6, start=1, end=4:
    // 0 1 2 3 4 5
    // 0 1 1 2 3 5
    // O(n)
    for (int i = end; i > start; i--) {
        tiles[i] = tiles[i - 1];
    }
}

void TileList::shiftLeft(int start, int end)
{
    // e.g. amount_tiles=6, start=4, end=1:
    // 0 1 2 3 4 5
    // 0 2 3 4 4 5
    // O(n)
    for (int i = end; i < start; i++) {
        tiles[i] = tiles[i + 1];
    }
}

void TileList::raise(int x, int y)
{
    // 0 1 2 3 4 5  -
    // 0 1 2 3 4 5  3
    // 0 1 2 4 5 5  3
    // 0 1 2 4 5 3  -
    // O(n)
    int index = indexOfTopTile(x, y);
    if (index == -1 || index == amount_tiles - 1) {
        // no tile found, or tile is already at top
        return;
    }
    Tile tmpTile = tiles[index];
    shiftLeft(amount_tiles - 1, index);
    tiles[amount_tiles - 1] = tmpTile;
}

void TileList::lower(int x, int y)
{
    // 0 1 2 3 4 5  -
    // 0 1 2 3 4 5  3
    // 0 0 1 2 4 5  3
    // 3 0 1 2 4 5  -
    // O(n)
    int index = indexOfTopTile(x, y);
    if (index == -1 || index == 0) {
        // no tile found, or tile is already at bottom
        return;
    }
    Tile tmpTile = tiles[index];
    shiftRight(0, index);
    tiles[0] = tmpTile;
}

void TileList::remove(int x, int y)
{
    //     V
    // 0 1 2 3 4 5
    // 0 1 3 4 5 5
    // 0 1 3 4 5 x
    // O(n)
    int index;
    if ((index = indexOfTopTile(x, y)) != -1) {
        shiftLeft(amount_tiles - 1, index);
        amount_tiles--;
    }
}

void TileList::removeAll(int x, int y)
{
    // O(n^2)
    int index;
    while ((index = indexOfTopTile(x, y)) != -1) {
        shiftLeft(amount_tiles - 1, index);
        amount_tiles--;
    }
}