/*
 *  Copyright 2025 Alexey Andreev.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
import java.util.ArrayDeque;
import java.util.Random;
import org.teavm.jso.dom.events.MouseEvent;
import org.teavm.jso.dom.html.HTMLDocument;
import org.teavm.jso.dom.html.HTMLElement;

public class Main {
    private static final HTMLDocument document = HTMLDocument.current();
    private static final int FIELD_SIZE = 12;
    private static final float MINE_RATIO = 1 / 7f;
    private static Cell[][] field;
    private static int remainingCells;
    private static boolean gameOver;

    public static void main(String[] args) {
        initField();
        placeMines();
        initStyle();
        initUI();
    }

    private static void initField() {
        field = new Cell[FIELD_SIZE][FIELD_SIZE];
        remainingCells = FIELD_SIZE * FIELD_SIZE;
        for (var i = 0; i < FIELD_SIZE; ++i) {
            for (var j = 0; j < FIELD_SIZE; ++j) {
                field[i][j] = new Cell();
            }
        }
    }

    private static void placeMines() {
        var mineCount = (int) (remainingCells * MINE_RATIO);
        var random = new Random();
        for (var i = 0; i < mineCount; ++i) {
            int row;
            int column;
            do {
                row = random.nextInt(FIELD_SIZE);
                column = random.nextInt(FIELD_SIZE);
            } while (field[row][column].mine);
            field[row][column].mine = true;
        }
        remainingCells -= mineCount;
    }

    private static void initStyle() {
        var styleElem = document.createElement("style");
        styleElem.setTextContent("""
            html, body {
                height: 100%;
                padding: 0;
                margin: 0;
            }
            body {
                display: flex;
                flex-direction: column;
                justify-content: center;
                align-items: center;
            }
            .field {
                display: grid;
                grid-template-columns: repeat(FIELD_SIZE, 1fr);
                grid-template-rows: repeat(FIELD_SIZE, 1fr);
                container-type: inline-size;
                font-weight: bold;
                font-family: sans-serif;
                width: 100vmin;
                height: 100vmin;
            }
            .cell {
                border-right: solid 1px black;
                border-bottom: solid 1px black;
                background-position: 10% 10%;
                background-size: 90%;
                display: flex;
                justify-content: center;
                align-items: center;
            }
            .cell.closed:hover {
                background-color: #0000000f;
            }
            .cell.open {
                background-color: #0000002f;
            }
            .cell.open > span {
                font-size: 4cqh;
                display: inline-block;
            }
            .mine {
                background-image: url("data:image/svg+xml;utf8,MINE");
                background-repeat: no-repeat;
            }
            .flag {
                background-image: url("data:image/svg+xml;utf8,FLAG");
                background-repeat: no-repeat;
            }
        """.replace("FIELD_SIZE", String.valueOf(FIELD_SIZE))
                .replace("MINE", MINE_IMAGE.replace("\"", "\\\""))
                .replace("FLAG", FLAG_IMAGE.replace("\"", "\\\"")));
        document.getHead().appendChild(styleElem);
    }

    private static void initUI() {
        var container = document.createElement("div");
        document.getBody().appendChild(container);
        container.setClassName("field");

        for (var i = 0; i < FIELD_SIZE; ++i) {
            for (var j = 0; j < FIELD_SIZE; ++j) {
                var cell = field[i][j];
                var element = document.createElement("div");
                element.getClassList().add("cell", "closed");
                cell.element = element;
                container.appendChild(element);

                var row = i;
                var column = j;
                cell.element.onEvent("contextmenu", event -> {
                    toggleFlag(row, column);
                    event.preventDefault();
                });
                cell.element.onClick(event -> {
                    if (event.getButton() == MouseEvent.LEFT_BUTTON) {
                        openCell(row, column);
                    }
                });
            }
        }
    }

    private static void openCell(int row, int column) {
        if (gameOver) {
            return;
        }
        var cell = field[row][column];
        if (cell.open || cell.flag) {
            return;
        }
        if (cell.mine) {
            loseGame();
            return;
        }

        var queue = new ArrayDeque<Integer>();
        queue.addLast(row);
        queue.addLast(column);
        while (!queue.isEmpty()) {
            row = queue.removeFirst();
            column = queue.removeFirst();
            cell = field[row][column];
            if (cell.open || cell.mine) {
                continue;
            }
            cell.open = true;
            cell.element.getClassList().remove("closed");
            cell.element.getClassList().add("open");
            if (--remainingCells == 0) {
                gameOver = true;
            }
            var mines = minesAround(row, column);
            if (mines > 0) {
                var span = document.createElement("span");
                span.setInnerText(String.valueOf(mines));
                cell.element.appendChild(span);
            } else {
                if (row > 0) {
                    if (column > 0) {
                        queue.addLast(row - 1);
                        queue.addLast(column - 1);
                    }
                    queue.addLast(row - 1);
                    queue.addLast(column);
                    if (column < FIELD_SIZE - 1) {
                        queue.addLast(row - 1);
                        queue.addLast(column + 1);
                    }
                }
                if (row < FIELD_SIZE - 1) {
                    if (column > 0) {
                        queue.addLast(row + 1);
                        queue.addLast(column - 1);
                    }
                    queue.addLast(row + 1);
                    queue.addLast(column);
                    if (column < FIELD_SIZE - 1) {
                        queue.addLast(row + 1);
                        queue.addLast(column + 1);
                    }
                }
                if (column > 0) {
                    queue.addLast(row);
                    queue.addLast(column - 1);
                }
                if (column < FIELD_SIZE - 1) {
                    queue.addLast(row);
                    queue.addLast(column + 1);
                }
            }
        }
    }

    private static int minesAround(int row, int column) {
        var count = 0;
        if (row > 0) {
            if (column > 0 && field[row - 1][column - 1].mine) {
                ++count;
            }
            if (field[row - 1][column].mine) {
                ++count;
            }
            if (column < FIELD_SIZE - 1 && field[row - 1][column + 1].mine) {
                ++count;
            }
        }
        if (row < FIELD_SIZE - 1) {
            if (column > 0 && field[row + 1][column - 1].mine) {
                ++count;
            }
            if (field[row + 1][column].mine) {
                ++count;
            }
            if (column < FIELD_SIZE - 1 && field[row + 1][column + 1].mine) {
                ++count;
            }
        }
        if (column > 0 && field[row][column - 1].mine) {
            ++count;
        }
        if (column < FIELD_SIZE - 1 && field[row][column + 1].mine) {
            ++count;
        }
        return count;
    }

    private static void toggleFlag(int row, int column) {
        if (gameOver) {
            return;
        }
        var cell = field[row][column];
        if (cell.open) {
            return;
        }
        cell.flag = !cell.flag;
        if (!cell.flag) {
            cell.element.getClassList().remove("flag");
        } else {
            cell.element.getClassList().add("flag");
        }
    }

    private static void loseGame() {
        gameOver = true;
        for (var i = 0; i < FIELD_SIZE; ++i) {
            for (var j = 0; j < FIELD_SIZE; ++j) {
                var cell = field[i][j];
                if (cell.mine) {
                    cell.element.getClassList().add("mine");
                }
            }
        }
    }

    static class Cell {
        boolean mine;
        boolean flag;
        boolean open;
        HTMLElement element;
    }

    private static final String MINE_IMAGE = "<svg xmlns=\"http://www.w3.org/2000/svg\" "
            + "height=\"24px\" viewBox=\"0 -960 960 960\" width=\"24px\">"
            + "<path d=\"M346-48q-125 0-212.5-88.5T46-350q0-125 86.5-211.5T344-648h13l27-47q12-22 36-28.5t46 6.5l30 "
            + "17 5-8q23-43 72-56t92 12l35 20-40 69-35-20q-14-8-30.5-3.5T570-668l-5 8 40 23q21 12 27.5 36t-5.5 "
            + "45l-27 48q23 36 34.5 76.5T646-348q0 125-87.5 212.5T346-48Zm0-80q91 0 "
            + "155.5-64.5T566-348q0-31-8.5-61T532-466l-26-41 42-72-104-60-42 72h-44q-94 0-163.5 60T125-350q0 92 64.5 "
            + "157T346-128Zm454-480v-80h120v80H800ZM580-828v-120h80v120h-80Zm195 81-56-56 85-85 56 56-85 "
            + "85ZM346-348Z\"/></svg>";

    private static final String FLAG_IMAGE = "<svg xmlns=\"http://www.w3.org/2000/svg\" height=\"24px\" "
            + "viewBox=\"0 -960 960 960\" width=\"24px\"><path d=\"M200-120v-680h360l16 "
            + "80h224v400H520l-16-80H280v280h-80Zm300-440Zm86 160h134v-240H510l-16-80H280v240h290l16 80Z\"/></svg>";
}