// ============================================================================
// Minesweeper — compute the neighbour-mine board from a mine layout
// ============================================================================
//
// mines is a flat row-major r×c list of 0/1. annotate() returns a board where
// each non-mine cell holds its count of adjacent mines (0..8) and each mine
// cell holds -1. reveal_safe() reports whether a click is safe.
//
// Run:  soma run minesweeper.cell --signal demo
// Test: soma test minesweeper.cell

cell Minesweeper {
    face {
        signal count_adjacent(mines: List, r: Int, c: Int, y: Int, x: Int) -> Int
        signal annotate(mines: List, r: Int, c: Int) -> List
        signal is_safe(mines: List, c: Int, y: Int, x: Int) -> Bool
        signal demo() -> List
    }

    on count_adjacent(mines: List, r: Int, c: Int, y: Int, x: Int) {
        let n = 0
        for dy in range(-1, 2) {
            for dx in range(-1, 2) {
                if dy != 0 || dx != 0 {
                    let ny = y + dy
                    let nx = x + dx
                    if ny >= 0 && ny < r && nx >= 0 && nx < c {
                        n = n + mines[ny * c + nx]
                    }
                }
            }
        }
        return n
    }

    on annotate(mines: List, r: Int, c: Int) {
        let out = []
        for y in range(0, r) {
            for x in range(0, c) {
                let v = -1
                if mines[y * c + x] == 0 {
                    v = count_adjacent(mines, r, c, y, x)
                }
                out = push(out, v)
            }
        }
        return out
    }

    on is_safe(mines: List, c: Int, y: Int, x: Int) {
        return mines[y * c + x] == 0
    }

    on demo() {
        // 3x3 with a single mine in the centre
        return annotate([0,0,0, 0,1,0, 0,0,0], 3, 3)
    }
}

cell test MinesweeperTests {
    rules {
        // single centre mine → every border cell counts 1, centre is -1
        assert annotate([0,0,0, 0,1,0, 0,0,0], 3, 3)[0] == 1
        assert annotate([0,0,0, 0,1,0, 0,0,0], 3, 3)[4] == -1
        assert annotate([0,0,0, 0,1,0, 0,0,0], 3, 3)[1] == 1
        // a corner mine touches exactly 3 cells
        assert count_adjacent([1,0,0, 0,0,0, 0,0,0], 3, 3, 1, 1) == 1
        assert annotate([1,0,0, 0,0,0, 0,0,0], 3, 3)[4] == 1
        assert annotate([1,0,0, 0,0,0, 0,0,0], 3, 3)[8] == 0
        // two adjacent mines
        assert count_adjacent([1,1,0, 0,0,0, 0,0,0], 3, 3, 1, 0) == 2
        // safety check
        assert is_safe([0,0,0, 0,1,0, 0,0,0], 3, 1, 1) == false
        assert is_safe([0,0,0, 0,1,0, 0,0,0], 3, 0, 0) == true
    }
}