// @ts-ignore
const {$} = window.fwdekker;
// @ts-ignore
import alea from "alea";
import {blurActiveElement, stringToHash} from "./Common";
import {customDifficulty, defaultDifficulty, difficulties} from "./Difficulty";
import {Display} from "./Display";
import {Field} from "./Field";
import {HighScores} from "./HighScores";
import {Preferences} from "./Preferences";
import {Solver} from "./Solver";
import {Statistics} from "./Statistics";
import {Overlay} from "./UI";


/**
 * Controls the interaction with a game of Minesweeper.
 */
export class Game {
    private readonly statistics = new Statistics();
    private readonly highScores = new HighScores();
    private statisticsTimer: number | undefined;

    private readonly canvas: HTMLCanvasElement;
    private readonly difficultySelect: HTMLSelectElement;
    private readonly newGameForm: HTMLFormElement;
    private readonly restartForm: HTMLFormElement;
    private readonly seedOverlay: Overlay;
    private readonly seedOpenForm: HTMLFormElement;
    private readonly seedInput: HTMLFormElement;
    private readonly undoForm: HTMLFormElement;
    private readonly redoForm: HTMLFormElement;
    private readonly hintForm: HTMLFormElement;
    private readonly solveForm: HTMLFormElement;
    private readonly customDifficultyOverlay: Overlay;
    private readonly widthInput: HTMLInputElement;
    private readonly heightInput: HTMLInputElement;
    private readonly minesInput: HTMLInputElement;
    private readonly solvableInput: HTMLInputElement;
    private readonly preferencesOverlay: Overlay;
    private readonly enableMarksInput: HTMLInputElement;
    private readonly showTooManyFlagsHintsInput: HTMLInputElement;
    private readonly preferencesOpenForm: HTMLFormElement;
    private readonly statisticsOverlay: Overlay;
    private readonly statisticsDiv: HTMLDivElement;
    private readonly statisticsResetForm: HTMLFormElement;
    private readonly statisticsOpenForm: HTMLFormElement;
    private readonly highScoresOverlay: Overlay;
    private readonly highScoresDiv: HTMLDivElement;
    private readonly highScoresResetForm: HTMLFormElement;
    private readonly highScoresOpenForm: HTMLFormElement;

    private readonly rng: any;
    private seed: string;

    private field: Field | null;
    private display: Display;
    private leftDown: boolean;
    private rightDown: boolean;
    private holdsAfterChord: boolean;


    /**
     * Constructs and starts a new game of Minesweeper.
     *
     * @param preferences the preferences to play the game under; may be changed during gameplay
     */
    constructor(preferences: Preferences) {
        this.canvas = $("#canvas");

        this.field = null;  // Placeholder until `initNewField`
        this.display = new Display(this.canvas, this.field, preferences);
        this.display.startDrawLoop();
        this.canvas.classList.remove("invisible");

        this.rng = alea("" + Date.now());
        this.seed = "" + this.rng.uint32();
        this.leftDown = false;
        this.rightDown = false;
        this.holdsAfterChord = false;

        this.initNewField();


        // Settings
        this.difficultySelect = $("#difficulty");
        difficulties.forEach(it => {
            const option = document.createElement("option");
            option.value = it.name;
            option.innerHTML = `${it.name}${it.description !== null ? ` (${it.description})` : ""}`;
            this.difficultySelect.add(option);
        });
        this.difficultySelect.addEventListener(
            "change",
            event => {
                event.preventDefault();

                const difficulty = difficulties[this.difficultySelect.selectedIndex - 1];
                this.difficultySelect.selectedIndex = 0;
                if (difficulty === undefined) return;

                if (difficulty.name !== customDifficulty.name) {
                    this.difficultySelect.selectedIndex = 0;
                    this.initNewField(difficulty.width, difficulty.height, difficulty.mineCount, difficulty.solvable);
                    return;
                }

                this.customDifficultyOverlay.show();
                this.widthInput.value = "" + (this.field?.width ?? defaultDifficulty.width);
                this.heightInput.value = "" + (this.field?.height ?? defaultDifficulty.height);
                this.minesInput.value = "" + (this.field?.mineCount ?? defaultDifficulty.mineCount);
                this.solvableInput.checked = this.field?.isSolvable ?? defaultDifficulty.solvable;
                this.setMineLimit();
                this.widthInput.focus();
            }
        );

        // Custom difficulty
        this.customDifficultyOverlay = new Overlay(
            $("#customDifficultyOverlay"),
            $("#customDifficultyForm"),
            $("#customDifficultyCancelForm"),
            () => {
                this.initNewField(
                    +this.widthInput.value,
                    +this.heightInput.value,
                    +this.minesInput.value,
                    this.solvableInput.checked
                );
            }
        );

        this.widthInput = $("#settingsWidth");
        this.widthInput.addEventListener("change", _ => this.setMineLimit());
        this.heightInput = $("#settingsHeight");
        this.heightInput.addEventListener("change", _ => this.setMineLimit());
        this.minesInput = $("#settingsMines");
        this.solvableInput = $("#settingsSolvable");

        // New game form
        this.newGameForm = $("#newGameForm");
        this.newGameForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.initNewField(this.field?.width, this.field?.height, this.field?.mineCount, this.field?.isSolvable);
                blurActiveElement();
            }
        );

        // Restart
        this.restartForm = $("#restartForm");
        this.restartForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.field?.undo();  // Undoes all
                blurActiveElement();
            }
        );

        // Seed
        this.seedInput = $("#seed");
        this.seedOpenForm = $("#seedOpenForm");
        this.seedOpenForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.seedOverlay.show();
                this.seedInput.value = this.seed;
                this.seedInput.focus();
                setTimeout(() => this.seedInput.select(), 0);
            }
        );
        this.seedOverlay = new Overlay(
            $("#seedOverlay"),
            $("#seedForm"),
            $("#seedCancelForm"),
            () => {
                this.initNewField(
                    this.field?.width,
                    this.field?.height,
                    this.field?.mineCount,
                    this.field?.isSolvable,
                    this.seedInput.value
                );
            }
        );

        // Undo
        this.undoForm = $("#undoForm");
        this.undoForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.field?.undo(1);
                blurActiveElement();
            }
        );

        // Redo
        this.redoForm = $("#redoForm");
        this.redoForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.field?.redo(1);
                blurActiveElement();
            }
        );

        // Hint
        this.hintForm = $("#hintForm");
        this.hintForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                if (this.field !== null) {
                    this.statistics.hintsRequested++;
                    this.display.hintSquare = (new Solver()).getHint(this.field);
                }
                blurActiveElement();
            }
        );

        // Solve
        this.solveForm = $("#solveForm");
        this.solveForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                if (this.field !== null) {
                    this.statistics.solverUsages++;
                    (new Solver()).solve(this.field);
                }
                blurActiveElement();
            }
        );

        // Preferences
        this.enableMarksInput = $("#preferencesEnableMarks");
        this.showTooManyFlagsHintsInput = $("#preferencesShowTooManyFlagsHints");
        this.preferencesOpenForm = $("#preferencesOpenForm");
        this.preferencesOpenForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.enableMarksInput.checked = preferences.marksEnabled;
                this.showTooManyFlagsHintsInput.checked = preferences.showTooManyFlagsHints;
                this.preferencesOverlay.show();
                blurActiveElement();
            }
        );
        this.preferencesOverlay = new Overlay(
            $("#preferencesOverlay"),
            $("#preferencesForm"),
            $("#preferencesCancelForm"),
            () => {
                preferences.marksEnabled = this.enableMarksInput.checked;
                preferences.showTooManyFlagsHints = this.showTooManyFlagsHintsInput.checked;
            }
        );

        // Statistics
        this.statisticsDiv = $("#statisticsDiv");
        this.statisticsOpenForm = $("#statisticsOpenForm");
        this.statisticsOpenForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.statisticsOverlay.show();
                blurActiveElement();
            }
        );
        this.statisticsOverlay = new Overlay(
            $("#statisticsOverlay"),
            null,
            $("#statisticsCloseForm")
        );
        this.statisticsResetForm = $("#statisticsResetForm");
        this.statisticsResetForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                if (!window.confirm("Are you sure you want to reset all statistics? This cannot be undone."))
                    return;

                this.statistics.clear();
            }
        );
        this.updateStatistics();

        // High scores
        this.highScoresDiv = $("#highScoresDiv");
        this.highScoresOpenForm = $("#highScoresOpenForm");
        this.highScoresOpenForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                this.highScoresDiv.innerHTML = this.highScores.generateHtmlReport();
                this.highScoresOverlay.show();
                blurActiveElement();
            }
        );
        this.highScoresOverlay = new Overlay(
            $("#highScoresOverlay"),
            null,
            $("#highScoresCloseForm")
        );
        this.highScoresResetForm = $("#highScoresResetForm");
        this.highScoresResetForm.addEventListener(
            "submit",
            event => {
                event.preventDefault();

                if (!window.confirm("Are you sure you want to reset all high scores? This cannot be undone."))
                    return;

                this.highScores.clear();
                this.highScoresDiv.innerHTML = this.highScores.generateHtmlReport();
            }
        );

        // Canvas
        this.canvas.addEventListener(
            "mousemove",
            event => {
                this.display.mouseSquare = this.field?.getSquareOrElse(
                    this.display.posToSquare({x: event.clientX, y: event.clientY}),
                    null
                );
            }
        );
        this.canvas.addEventListener(
            "mouseleave",
            _ => {
                this.display.mouseSquare = null;
                this.leftDown = false;
                this.rightDown = false;
                this.holdsAfterChord = false;
                this.display.mouseHoldChord = false;
            }
        );
        this.canvas.addEventListener("contextmenu", event => event.preventDefault());
        this.canvas.addEventListener(
            "mousedown",
            event => {
                event.preventDefault();
                if (this.field === null) return;

                this.field.runUndoably(() => {
                    const coords = this.display.posToSquare({x: event.clientX, y: event.clientY});
                    if (this.field === null || !this.field.hasSquareAt(coords)) return;

                    switch (event.button) {
                        case 0:
                            this.leftDown = true;
                            break;
                        case 2:
                            if (!this.leftDown) {
                                const square = this.field.getSquareOrElse(coords);
                                if (square !== null) {
                                    if (square.hasFlag) {
                                        this.field.toggleFlag(coords);
                                        if (preferences.marksEnabled)
                                            this.field.toggleMark(coords);
                                    } else if (square.hasMark) {
                                        this.field.toggleMark(coords);
                                    } else {
                                        this.field.toggleFlag(coords);
                                    }
                                }
                            }

                            this.rightDown = true;
                            break;
                    }
                });

                this.display.hintSquare = null;
                this.display.mouseHoldUncover = this.leftDown && !this.holdsAfterChord;
                this.display.mouseHoldChord = this.leftDown && this.rightDown;
            }
        );
        this.canvas.addEventListener(
            "mouseup",
            event => {
                event.preventDefault();
                if (this.field === null) return;

                this.field.runUndoably(() => {
                    const coords = this.display.posToSquare({x: event.clientX, y: event.clientY});
                    if (this.field === null || !this.field.hasSquareAt(coords)) return;

                    switch (event.button) {
                        case 0:
                            if (this.leftDown && this.rightDown)
                                this.field.chord(coords);
                            else if (!this.holdsAfterChord && this.leftDown)
                                this.field.uncover(coords);

                            this.leftDown = false;
                            this.holdsAfterChord = this.rightDown;
                            break;
                        case 1:
                            this.field.chord(coords);
                            break;
                        case 2:
                            if (this.leftDown && this.rightDown)
                                this.field.chord(coords);

                            this.rightDown = false;
                            this.holdsAfterChord = this.leftDown;
                            break;
                    }
                });

                this.display.hintSquare = null;
                this.display.mouseHoldUncover = this.leftDown && !this.holdsAfterChord;
                this.display.mouseHoldChord = this.leftDown && this.rightDown;
            }
        );
    }


    /**
     * Adjusts the limits on the mine count input field.
     *
     * @private
     */
    private setMineLimit(): void {
        this.minesInput.max = "" + Field.maxMines(+this.widthInput.value, +this.heightInput.value);
    }

    /**
     * Updates the statistics report in the statistics overview.
     *
     * @private
     */
    private updateStatistics(): void {
        this.statisticsDiv.innerHTML = this.statistics.generateHtmlReport();
    }

    /**
     * Initializes a new field according to the given parameters
     *
     * @param width the width of the field
     * @param height the height of the field
     * @param mineCount the number of mines to place in the field
     * @param solvable whether the field is guaranteed to be solvable
     * @param seed the seed to generate the field width, or `null` if a new field should be chosen
     * @private
     */
    private initNewField(
        width: number = defaultDifficulty.width,
        height: number = defaultDifficulty.height,
        mineCount: number = defaultDifficulty.mineCount,
        solvable: boolean = defaultDifficulty.solvable,
        seed: string | null = null
    ) {
        this.seed = seed ?? "" + this.rng.uint32();
        this.field = new Field(
            width, height, mineCount, solvable,
            isNaN(+this.seed) ? stringToHash(this.seed) : +this.seed,
            this.statistics,
            this.highScores
        );
        this.display.setField(this.field);

        // Start timer for statistics
        let lastTime: number | null = null;
        window.clearInterval(this.statisticsTimer);
        this.statisticsTimer = window.setInterval(() => {
            if (this.field === null) return;

            const elapsedTime = this.field.elapsedTime;
            this.statistics.timeSpent += elapsedTime - (lastTime ?? 0);
            lastTime = elapsedTime;

            this.updateStatistics();
        }, 1000);
    }
}