// this file should contain a class that gets info from /api/showings/{id}
// and renders the seat chooser
// there may be multiple seats selected at once
// the input is a matrix with null OR a seat object

class Seat {
    constructor(id, row, col, linked, reserved, type) {
        this.id = id; // database id
        this.row = row;
        this.col = col;
        this.linked = linked; // linked seat
        this.reserved = reserved;
        this.type = type; // seat type
    }
}

class SeatChooser {
    setLoadingStatus(msg) {
        // if no status element exists, create one
        if (!this.container.querySelector('#seat-chooser-status')) {
            let status = document.createElement('div');
            // h2 for "Loading..."
            // span for message
            status.innerHTML = `<h2>Loading...</h2><span id="seat-chooser-status-message"></span>`;
            status.id = 'seat-chooser-status';
            status.style.textAlign = 'center';
            this.container.appendChild(status);
        }
        // set the message
        this.container.querySelector('#seat-chooser-status-message').innerText = msg;
    }

    constructor(showingId, container, submitCallback) {
        this.showingId = showingId; // id of the showing
        this.container = container; // the container to render the seat chooser in
        this.submitCallback = submitCallback; // callback function to call when the user submits the form

        this.setLoadingStatus("Initializing...");

        this.seats = []; // array of nulls and Seat objects

        this.selectedSeats = []; // array of Seat objects

        this.init();
    }

    async init() {
        this.setLoadingStatus("Fetching showing data...");
        let showingJson = await (await fetch(`/api/showings/${this.showingId}`)).json();
        this.setLoadingStatus("Fetching seats...");
        let roomMatrix = await (await fetch(`/api/showings/${this.showingId}/seatMatrix`)).json();
        // Matrix<json | null> -> Matrix<Seat | null>
        this.setLoadingStatus("Processing seats...");
        console.log("Matrix<json | null> -> Matrix<Seat | null>");
        this.seats = roomMatrix.map((row, rowIndex) => {
            return row.map((seat, colIndex) => {
                if (seat === null) {
                    return null;
                }
                this.setLoadingStatus("Processing seats... " + Math.round((rowIndex * row.length + colIndex) / (row.length * row.length) * 100) + "%");
                return new Seat(
                    seat['seat_id'],
                    seat['seat_row'],
                    seat['seat_column'],
                    seat['seat_linked_id'],
                    seat['reserved'],
                    seat['seat_type']
                );
            });
        });
        console.log(this.seats);
        await this.fixCoronaSeating();
        this.render();
    }

    async fixCoronaSeating() {
        // the seat left or right of a set of reserved seats are not available
        this.seats.forEach((row, rowIndex) => {
            row.forEach((seat, colIndex) => {
                if (seat === null) return;
                if (seat.reserved) {
                    if (row[colIndex - 1] && !row[colIndex - 1].reserved)
                        row[colIndex - 1].type = 'not_available';
                    if (row[colIndex + 1] && !row[colIndex + 1].reserved)
                        row[colIndex + 1].type = 'not_available';
                }
            });
        });
    }

    render() {
        this.setLoadingStatus("Rendering...");
        let linkedCache = false;
        // render the seat chooser
        // this -> row -> seat
        this.container.innerHTML = '';
        this.seats.forEach((row, rowIndex) => {
            let rowDiv = document.createElement('div');
            rowDiv.classList.add('row');
            row.forEach((seat, colIndex) => {
                let seatDiv = document.createElement('div');
                if (seat) {
                    seatDiv.classList.add('seat');
                    if (seat.reserved) {
                        seatDiv.classList.add('reserved');
                        seatDiv.title = 'This seat is reserved';
                    }

                    if (seat.linked) {
                        // if cache is false, then this is the first seat in the linked pair
                        if (!linkedCache) {
                            seatDiv.classList.add('linked-left');
                            linkedCache = true;
                        } else {
                            seatDiv.classList.add('linked-right');
                            linkedCache = false;
                        }
                    } else {
                        linkedCache = false;
                    }

                    seatDiv.innerText = `${seat.row}-${seat.col}`;

                    switch (seat.type) {
                        case 'not_available':
                            seatDiv.title = 'This seat is not available';
                            seatDiv.classList.add('disabled');
                            break;

                        case 'wheelchair':
                            seatDiv.title = 'This seat is wheelchair accessible';
                            seatDiv.classList.add('wheelchair');
                            break;

                        case 'loveseat':
                            seatDiv.title = 'This seat is a loveseat';
                            seatDiv.classList.add('loveseat');
                            break;

                        case 'standard':
                            seatDiv.title = 'This is a standard seat';
                            break;
                    }

                    seatDiv.dataset.id = seat.id;
                    seatDiv.dataset.row = seat.row;
                    seatDiv.dataset.col = seat.col;

                    seatDiv.addEventListener('click', (e) => {
                        this.toggleSeat(seat, e);
                    });
                } else {
                    seatDiv.classList.add('no-seat');
                }
                rowDiv.appendChild(seatDiv);
            });
            this.container.appendChild(rowDiv);
        });

        // button container
        let buttonContainer = document.createElement('div');
        buttonContainer.style.display = 'flex';

        // clear button
        let clearButton = document.createElement('button');
        clearButton.classList.add('button');
        clearButton.style.margin = '1rem';
        clearButton.innerText = 'Clear';
        clearButton.addEventListener('click', () => {
            this.clearSelection();
        });
        buttonContainer.appendChild(clearButton);

        // submit button
        let submitButton = document.createElement('button');
        submitButton.classList.add('button');
        submitButton.style.margin = '1rem';
        submitButton.innerText = 'Submit';
        submitButton.addEventListener('click', () => {
            this.submitCallback(this);
        });
        buttonContainer.appendChild(submitButton);
        this.container.appendChild(buttonContainer);
    }

    toggleSeat(seat, e) {
        // toggle the seat
        // because of linked seats, we need to toggle both seats
        if (seat.reserved || seat.type == 'not_available') return;
        e.target.classList.toggle('selected');
        if (seat.linked) {
            // beware that you can click on the left or right seat
            // the left seat has class linked-left and the right seat has class linked-right
            let leftbool = e.target.classList.contains('linked-left');
            let linkedSeat = this.seats[seat.row - 1][leftbool ? seat.col - 1 : seat.col + 1];
            if (leftbool) e.target.nextElementSibling.classList.toggle('selected');
            else e.target.previousElementSibling.classList.toggle('selected');
            if (this.selectedSeats.includes(linkedSeat)) {
                this.selectedSeats.splice(this.selectedSeats.indexOf(linkedSeat), 1);
                this.selectedSeats.splice(this.selectedSeats.indexOf(seat), 1);
            } else {
                this.selectedSeats.push(linkedSeat);
                this.selectedSeats.push(seat);
            }
        } else {
            if (this.selectedSeats.includes(seat)) {
                this.selectedSeats.splice(this.selectedSeats.indexOf(seat), 1);
            } else {
                this.selectedSeats.push(seat);
            }
        }
    }

    clearSelection() {
        this.selectedSeats.forEach(seat => {
            let seatDiv = this.container.querySelector(`[data-id="${seat.id}"]`);
            seatDiv.classList.remove('selected');
        });
        this.selectedSeats = [];
    }
}

let seatChooser = new SeatChooser(1, document.getElementById('seat-chooser'), (sc) => {
    // gray overlay and show selected seats
    let overlay = document.createElement('div');
    overlay.style.position = 'fixed';
    overlay.style.top = '0';
    overlay.style.left = '0';
    overlay.style.width = '100vw';
    overlay.style.height = '100vh';
    overlay.style.backgroundColor = 'rgba(0,0,0,0.5)';
    overlay.style.display = 'flex';
    overlay.style.justifyContent = 'center';
    overlay.innerText = 'You selected the following seats: ' + sc.selectedSeats.map(seat => `${seat.row}-${seat.col}`).join(', ');
    overlay.addEventListener('click', () => {
        overlay.remove();
    });
    sc.container.appendChild(overlay);
});