/// SPDX-License-Identifier: GPL-3.0-or-later
/// SPDX-FileCopyrightText: Copyright © 2016-2021 Tony Garnock-Jones <tonyg@leastfixedpoint.com>

import { $QuitDataspace, Double, Facet, Inbound, Outbound, floatValue } from '@syndicate-lang/core';
activate import { WindowEvent, template, Anchor } from '@syndicate-lang/html';
activate import { PeriodicTick } from '@syndicate-lang/timer';

assertion type Position(x, y);
assertion type GameOver();
assertion type Score(count);
message type IncreaseScore();
message type Reset();

const BOARD_HEIGHT = 567;
const FLAPPY_WIDTH = 57;
const FLAPPY_HEIGHT = 41;
const FLAPPY_XPOS = 212;
const PILLAR_WIDTH = 86;
const PILLAR_GAP = 158;
const FIELD_HEIGHT = 561;
const PILLAR_HEAD_HEIGHT = 40;

boot {
    spawn named 'game-factory' {
        on start spawnGame(thisFacet);
        during GameOver() => {
            on stop spawnGame(thisFacet);
            on message WindowEvent('+keypress', $_e) => send message Reset();
            on message WindowEvent('+click', $_e) => send message Reset();
        }
    }
}

function spawnGame<T>(thisFacet: Facet<T>) {
    spawn dataspace named 'GameInstance' {
        spawn named 'game-instance-control' {
            during GameOver() => assert Outbound(GameOver());
            on message Inbound(Reset()) => send message $QuitDataspace;
        }

        spawn named 'score' {
            let ui = new Anchor();
            field score: number = 0;

            assert Score(this.score);

            on start react {
                assert Outbound(ui.html('#board-area',
                                        template`<h1 class="score">${this.score}</h1>`));
                stop on asserted GameOver() => react {
                    assert Outbound(ui.html('#board-area',
                                            template`<h1 class="score">${this.score}<br/>GAME OVER</h1>`));
                }
            }

            on message IncreaseScore() => this.score++;
        }

        spawn named 'flappy' {
            let ui = new Anchor();
            field xpos: number = 0;
            field ypos: number = 312;
            field yvel: number = 0;

            assert Position(Double(this.xpos), Double(this.ypos));

            assert Outbound(
                ui.html('#board-area',
                        template`<div class="flappy"
                                      style="${`transform: rotate(${2 * this.yvel}deg);
                                                top: ${this.ypos}px`}"></div>`));

            on (this.ypos > BOARD_HEIGHT - FLAPPY_HEIGHT) {
                this.ypos = BOARD_HEIGHT - FLAPPY_HEIGHT;
                react {
                    assert GameOver();
                }
            }

            on start react {
                stop on asserted GameOver();

                on message Inbound(WindowEvent('+keypress', $_e)) => this.yvel = -10;
                on message Inbound(WindowEvent('+click', $_e)) => this.yvel = -10;

                const ms_per_tick = 1000.0 / 60;
                on message Inbound(PeriodicTick(Double(ms_per_tick))) => {
                    this.xpos += 0.15 * ms_per_tick;
                    this.ypos = (this.ypos + this.yvel);
                    this.yvel += ms_per_tick * 0.05;
                }
            }
        }

        spawn named 'border-scroll' {
            let ui = new Anchor();
            field pos: number = 0;
            on asserted Position($xpos, _) => this.pos = floatValue(xpos) % 23;
            assert Outbound(ui.html(
                '#board-area',
                template`<div class="scrolling-border" style="${`background-position-x: ${-this.pos}px`}"></div>`,
                0));
        }

        spawn named 'pipe-factory' {
            field nextPipe: number = 0;
            on asserted Score(this.nextPipe) => spawnPipe(thisFacet, this.nextPipe++);
        }

        function spawnPipe<T>(thisFacet: Facet<T>, i: number) {
            spawn named ['pipe', i] {
                let ui = new Anchor();

                const xlocation = (i + 1) * 324;

                const upperHeight =
                    Math.random() * (FIELD_HEIGHT - PILLAR_GAP - PILLAR_HEAD_HEIGHT * 6)
                    + PILLAR_HEAD_HEIGHT * 3;
                const lowerHeight = FIELD_HEIGHT - upperHeight - PILLAR_GAP;

                stop on (this.xpos < -(PILLAR_WIDTH + FLAPPY_XPOS));

                on start react { stop on (this.xpos <= 0) send message IncreaseScore(); };

                field xpos: number = xlocation;
                on asserted Position($xpos, _) => this.xpos = xlocation - floatValue(xpos);

                on asserted Position($xpos, $ypos) => {
                    if (touchingPillar(floatValue(xpos), floatValue(ypos))) {
                        react {
                            assert GameOver();
                        }
                    }
                }

                assert Outbound(ui.html(
                    '#board-area',
                    template`<div class="pillars">
                             <div class="pillar pillar-upper"
                                  style="${`left: ${this.xpos + FLAPPY_XPOS}px; height: ${upperHeight}px;`}"></div>
                             <div class="pillar pillar-lower"
                                  style="${`left: ${this.xpos + FLAPPY_XPOS}px; height: ${lowerHeight}px;`}"></div>
                             </div>`));

                function touchingPillar(xpos: number, ypos: number): boolean {
                    const inHorizontalRange =
                        (xpos + FLAPPY_WIDTH >= xlocation) && (xpos <= xlocation + PILLAR_WIDTH);
                    const aboveGapTop = (ypos <= upperHeight);
                    const belowGapBottom = (ypos + FLAPPY_HEIGHT >= upperHeight + PILLAR_GAP);
                    return inHorizontalRange && (aboveGapTop || belowGapBottom);
                }
            }
        }
    }
}