// Combo-multiplier golden (P3.2): drive seeded boards through the full cascade
// settle and snapshot the per-round scoring. Each round's base points
// (`score_round`) are scaled by `combo_multiplier(round)` = the 1-based round
// index, so round 1 ×1, round 2 ×2, round 3 ×3, …; `resolve` accumulates the
// multiplied sum into `Board.score` and reports it as `Cascade.awarded`.
//
// Three scenes prove the rule end to end:
//   - single-depth1: one clear, depth 1 → base ×1 = base exactly (NO bonus).
//   - cascade-depth2: the P2.4 cascade board (seed 7) → a real 2-round chain
//     whose multiplied total (90) strictly beats the flat sum (60).
//   - chain-depth3: the same crafted board at seed 10 → a 3-round chain,
//     30×1 + 30×2 + 30×3 = 180, well above the flat 90.
//
// For each scene the starting board and every round's (cleared, base, multiplier,
// round points) are printed so the golden is self-explanatory, the flat and
// multiplied totals are printed side by side, and `resolve` on a fresh identical
// board is asserted to award EXACTLY the multiplied total into `Board.score`.
#import "modules/std.sx";
#import "board.sx";
t :: #import "test.sx";

// Inverse of `gem_char`: map a board character back to its Gem so each board can
// be written as a human-readable grid. The hole glyph maps to `.empty`.
char_to_gem :: (c: u8) -> Gem {
    if c == EMPTY_CHAR { return .empty; }
    for 0..GEM_COUNT (i) {
        if GEM_CHARS[i] == c { return cast(Gem) i; }
    }
    .red
}

// Load an 8x8 board from `rows` (top row first, each exactly BOARD_COLS chars),
// seeded RNG, running score zeroed so `board.score` ends equal to the payout.
load_board :: (rows: []string, seed: s64) -> Board {
    b : Board = ---;
    for 0..BOARD_ROWS (row) {
        line := rows[row];
        for 0..BOARD_COLS (col) {
            b.set(col, row, char_to_gem(line[col]));
        }
    }
    b.rng = rng_seeded(seed);
    b.score = 0;
    b
}

// One scene: drive the settle one round at a time so each round is visible in the
// snapshot — score_round BEFORE the clear, multiplier off the 1-based round index,
// mirroring `resolve` exactly. Print per-round (cleared, base, multiplier, round
// points) and the flat-vs-multiplied totals, then assert `resolve` on a fresh
// identical board awards `want_mult` into `Board.score` and reports it as
// `Cascade.awarded` at the same depth. A depth-1 settle must equal the flat sum
// (no bonus); a deeper chain must strictly exceed it.
scene :: (name: string, rows: []string, seed: s64, want_flat: s64, want_mult: s64) {
    print("== {} ==\n", name);
    b := load_board(rows, seed);
    out(board_dump(@b));

    flat : s64 = 0;
    mult : s64 = 0;
    depth : s64 = 0;
    while true {
        base := score_round(@b);
        n := resolve_step(@b);
        if n == 0 { break; }
        depth += 1;
        m := combo_multiplier(depth);
        print("round {}: cleared {} base {} x{} = {}\n", depth, n, base, m, base * m);
        flat += base;
        mult += base * m;
    }
    print("flat sum {}\n", flat);
    print("multiplied total {}\n", mult);

    t.expect(flat == want_flat, concat(name, ": flat sum exact"));
    t.expect(mult == want_mult, concat(name, ": multiplied total exact"));
    if depth >= 2 {
        t.expect(mult > flat, concat(name, ": multi-round chain beats flat sum"));
    } else {
        t.expect(mult == flat, concat(name, ": single round scores flat (no bonus)"));
    }

    // The public `resolve` on a fresh identical board reproduces the payout:
    // accumulates the multiplied total into `Board.score` and reports it as
    // `Cascade.awarded`, at the same depth.
    b2 := load_board(rows, seed);
    c := resolve(@b2);
    t.expect(c.depth == depth, concat(name, ": resolve depth matches manual loop"));
    t.expect(c.awarded == want_mult, concat(name, ": resolve awarded equals multiplied total"));
    t.expect(b2.score == want_mult, concat(name, ": resolve accumulates into board.score"));
}

main :: () -> s32 {
    print("== combo (cascade multiplier) ==\n");

    // Single-round clear (seed 0): one RRR clears and the refill makes no new
    // match, so the settle stops at depth 1 → base 30 ×1 = 30, exactly the flat
    // value. Proves there is no combo bonus on a single round.
    scene("single-depth1", .[
        "RRRGOGOG",
        "GOGOGOGO",
        "OGOGOGOG",
        "GOGOGOGO",
        "OGOGOGOG",
        "GOGOGOGO",
        "OGOGOGOG",
        "GOGOGOGO",
    ], 0, 30, 30);

    // The P2.4 cascade board (seed 7): round 1 clears the horizontal BBB (base 30
    // ×1), round 2 the gravity-formed vertical RRR (base 30 ×2) → 30 + 60 = 90,
    // strictly above the flat 30 + 30 = 60.
    scene("cascade-depth2", .[
        "OGOGOGOG",
        "GOGOGOGO",
        "RGOGOGOG",
        "BBBOGOGO",
        "RGOGOGOG",
        "ROGOGOGO",
        "OGOGOGOG",
        "GOGOGOGO",
    ], 7, 60, 90);

    // The same crafted board at seed 10: the refill after round 2 sets up a third
    // len-3 clear, a controlled 3-round chain → 30×1 + 30×2 + 30×3 = 180, well
    // above the flat 90.
    scene("chain-depth3", .[
        "OGOGOGOG",
        "GOGOGOGO",
        "RGOGOGOG",
        "BBBOGOGO",
        "RGOGOGOG",
        "ROGOGOGO",
        "OGOGOGOG",
        "GOGOGOGO",
    ], 10, 90, 180);

    print("ok: combo multiplier scales cascade rounds\n");
    return 0;
}