const Grid = @import("grid.zig");
const Piece = @import("piece.zig");

pub fn moveRight(grid: Grid, piece: Piece) Piece {
    var new_piece = piece;
    new_piece.col += 1;
    for (new_piece.structure) |_, y| {
        for (new_piece.structure[y]) |_, x| {
            if (new_piece.structure[y][x] and
                    @intCast(i32, x) + new_piece.col > Grid.ncolumns - 1) {
                return piece;
            }
            if (new_piece.structure[y][x] and
                    !grid.cells[@intCast(usize, new_piece.row + @intCast(i32, y))][@intCast(usize, new_piece.col + @intCast(i32, x))].free) {
                return piece;
            }
        }
    }
    return new_piece;
}

pub fn moveLeft(grid: Grid, piece: Piece) Piece {
    var new_piece = piece;
    new_piece.col -= 1;
    for (new_piece.structure) |_, y| {
        for (new_piece.structure[y]) |_, x| {
            if (new_piece.structure[y][x] and
                    @intCast(i32, x) + new_piece.col < 0) {
                return piece;
            }
            if (new_piece.structure[y][x] and
                    !grid.cells[@intCast(usize, new_piece.row + @intCast(i32, y))][@intCast(usize, new_piece.col + @intCast(i32, x))].free) {
                return piece;
            }
        }
    }
    return new_piece;
}

pub fn moveDown(grid: Grid, piece: Piece) Piece {
    var new_piece = piece;
    new_piece.row += 1;
    for (new_piece.structure) |_, y| {
        for (new_piece.structure[y]) |_, x| {
            if (new_piece.structure[y][x] and
                    @intCast(i32, y) + new_piece.row > Grid.nrows - 1) {
                return piece;
            }
            if (new_piece.structure[y][x] and
                    !grid.cells[@intCast(usize, new_piece.row + @intCast(i32, y))][@intCast(usize, new_piece.col + @intCast(i32, x))].free) {
                return piece;
            }
        }
    }
    return new_piece;
}