//! FIFA 17 store tab-bar repair — pre-warm the purchase groups before screen-show.
//!
//! # Confirmed root cause (live, 2026-08-19)
//!
//! `FUN_18007e5e0(ctx, panel)` is the native tab binder the screen framework
//! invokes at store screen-show. It is an unrolled six-slot loop; each slot gates
//! on one hard-coded category token and either publishes that group's id as
//! `PANEL_ID` for the slot, or hides the slot:
//!
//! ```text
//! if (FUN_180014df0(_, idx))                                  // token present?
//!     (*(panel_vtbl+0x48))(panel, slot, "PANEL_ID", FUN_180014580(_, idx));
//! else
//!     (*(panel_vtbl+0xa0))(panel, slot);                      // hide slot
//! ```
//!
//! slot -> token, in bind order: `mypacks, bronze, silver, gold, special, points`.
//! The gate `FUN_180014df0` resolves the token through `FUN_180014380`, which scans
//! the loaded purchase groups (stride `0x108`) comparing the token at `group+0x70`.
//! So a tab appears iff a purchase group carrying that token is loaded AT BIND TIME.
//!
//! The bind detour below measured the ground truth on the retail client:
//!
//! ```text
//! STORE_TABS: bind generation=2 mask=0x00 ...        <- empty at screen-show
//! STORE_TABS: rebound generation=2 mask=0x0e (...)   <- groups present ~instantly after
//! ```
//!
//! `mask=0x00` at screen-show confirms the container is empty when the framework
//! binds, so all six slots hide and no tab bar is built. The store's own
//! `GET store/purchasegroup/all` only returns *after* screen-show, so re-entry works
//! (groups cached) but first entry does not. (`0x0e` = bronze|silver|gold; bit 0
//! `mypacks` is clear because an empty My Packs serves no `mypacks` group.)
//!
//! # What did NOT work, and why this module changed
//!
//! A previous version re-invoked the binder at the next render, once the groups had
//! arrived (`rebound ... mask=0x0e` above). The movie built NO tab bar from that
//! late bind: the Scaleform movie only honours the framework's OWN bind at
//! screen-show, not a later re-publish/commit. That approach is abandoned.
//!
//! # This module: make the container non-empty BEFORE the first bind
//!
//! The only publish the movie honours is the framework's bind at screen-show, and
//! re-entry proves that bind builds the bar correctly when the container is already
//! full. So the fix is to load the purchase groups BEFORE the store screen is shown.
//!
//! `FUN_180017870(storefront)` issues the store's own `GET store/purchasegroup/all`.
//! Firing it from the FUT hub event pump (a real game thread, well before the store
//! screen exists) gives the response time to arrive and populate the container, so
//! the first screen-show bind sees a full list and binds the tabs natively — exactly
//! the re-entry path, on first entry.
//!
//! The bind detour is retained purely as the SENSOR: the first-entry bind mask is
//! the safe, definitive measurement of whether the pre-warm populated the container
//! in time. `mask != 0` at first bind ⇒ pre-warm worked and the tabs bind natively;
//! `mask == 0` (with `storefront_seen=1` in the pre-warm log) ⇒ a hub-time request
//! cannot land in time and the remaining route is the extracted `StoreFront.apt`.
//!
//! # Fail-closed
//!
//! * Pre-warm fires at most once per process, claimed atomically, and only once the
//!   storefront singleton is non-null; the storefront pointer is read through a
//!   guarded load and the request function's signature is validated before the call.
//! * The bind detour only reads (captures pointers, probes the game's own gate with
//!   a provably-dead `this`) and never mutates store state.
//! * Image plus every function signature are verified before any write and again
//!   under thread suspension; one wrong byte aborts with no write and no call.
//!
//! # Promotion
//!
//! PROMOTED: armed by the build, never by an environment variable (see
//! [`REPAIR_PROMOTED`]). Rollback is a `version.dll` file swap.

use core::ffi::c_void;
use core::sync::atomic::{AtomicBool, AtomicU32, AtomicU64, AtomicUsize, Ordering};
use windows_sys::Win32::System::Diagnostics::Debug::FlushInstructionCache;
use windows_sys::Win32::System::LibraryLoader::{
    GetModuleHandleA, GetModuleHandleExA, GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS,
    GET_MODULE_HANDLE_EX_FLAG_PIN,
};
use windows_sys::Win32::System::Memory::{
    VirtualFree, VirtualProtect, MEM_RELEASE, PAGE_EXECUTE_READWRITE,
};
use windows_sys::Win32::System::Threading::{GetCurrentProcess, GetCurrentThreadId};

/// Native tab binder `FUN_18007e5e0(ctx, panel)`, invoked by the screen framework
/// at screen-show. Detoured as the read-only sensor: captures the gate mask it saw.
const BIND_RVA: usize = 0x7e5e0;
/// Category gate `FUN_180014df0(dead_this, idx) -> bool`: maps `idx` to one of the
/// six hard-coded tokens and reports whether a loaded purchase group carries it.
const HAS_CATEGORY_RVA: usize = 0x14df0;
/// `FUN_180017870(storefront)` issues `GET store/purchasegroup/all` — the exact call
/// the store screen makes at entry (from `0x18007f25e`). Fired early to pre-warm.
const REQUEST_GROUPS_RVA: usize = 0x17870;
/// `*(base + STOREFRONT_GLOBAL_RVA)` is the storefront the store code passes to its
/// request/lookup helpers (loaded at `0x18007f25e`, right before the pack-list GET).
const STOREFRONT_GLOBAL_RVA: usize = 0x2de0d0;

/// Gate indices in slot order: `mypacks, bronze, silver, gold, special, points`.
/// Taken from the binder's unrolled call sequence, not from the index order of
/// `FUN_180014580`'s jump table (which is deliberately different).
const GATE_INDICES: [u32; 6] = [0, 2, 3, 4, 5, 1];

/// Whole-instruction prologue length relocated into the trampoline; also the number
/// of bytes overwritten by the entry detour. 15 bytes, a clean boundary covering the
/// 14-byte absolute jump.
const COPY_LEN: usize = 15;
const ABS_JUMP_LEN: usize = 14;

/// First 15 bytes of `FUN_18007e5e0`: `mov [rsp+8],rbx; mov [rsp+0x10],rbp;
/// mov [rsp+0x18],rsi` = 5 + 5 + 5.
const BIND_SIGNATURE: [u8; COPY_LEN] = [
    0x48, 0x89, 0x5c, 0x24, 0x08, 0x48, 0x89, 0x6c, 0x24, 0x10, 0x48, 0x89, 0x74, 0x24, 0x18,
];
/// First 15 bytes of `FUN_180014df0`. Validated before we ever call it, so the gate
/// probe only runs on the exact build it was reversed against.
const HAS_CATEGORY_SIGNATURE: [u8; 15] = [
    0x40, 0x53, 0x48, 0x83, 0xec, 0x20, 0x33, 0xdb, 0x44, 0x8b, 0xc3, 0x85, 0xd2, 0x74, 0x35,
];
/// First 18 bytes of `FUN_180017870`. Validated before we ever call it, so the
/// pre-warm only fires the genuine request on the exact build it was reversed against.
const REQUEST_GROUPS_SIGNATURE: [u8; 18] = [
    0x40, 0x57, 0x48, 0x81, 0xec, 0x90, 0x00, 0x00, 0x00, 0x48, 0xc7, 0x44, 0x24, 0x20, 0xfe, 0xff,
    0xff, 0xff,
];

type BindFn = unsafe extern "system" fn(*mut c_void, *mut c_void) -> *mut c_void;
type HasCategoryFn = unsafe extern "system" fn(*mut c_void, u32) -> u8;
type RequestGroupsFn = unsafe extern "system" fn(*mut c_void) -> usize;

/// The tab-bar repair is PROMOTED: armed by the build, never by an environment
/// variable, so every launch path (Steam, the launcher, a bare `umu-run`) behaves
/// identically. Promotion does not weaken any check — the signature gate, the image
/// validation and the thread quiesce all remain in the runtime evidence path.
pub(crate) const REPAIR_PROMOTED: bool = true;

/// Compile-time contract: the repair stays build-armed. Regressing it to an env gate
/// would silently restore the missing first-entry tab bar on a normal launch, so it
/// must be a deliberate, visible change here rather than a missing variable.
const _: () = assert!(REPAIR_PROMOTED);

static REPAIR_ENABLED: AtomicBool = AtomicBool::new(false);
static BIND_TRAMPOLINE: AtomicUsize = AtomicUsize::new(0);
static STORE_BASE: AtomicUsize = AtomicUsize::new(0);
static BIND_ENTRIES: AtomicU64 = AtomicU64::new(0);
/// Gate mask the framework's most recent bind observed (bit N = slot N would bind).
static LAST_BIND_MASK: AtomicU32 = AtomicU32::new(0);
static LAST_THREAD: AtomicUsize = AtomicUsize::new(0);
/// Set once the pre-warm request has been fired (or is provably unnecessary).
static PREWARM_DONE: AtomicBool = AtomicBool::new(false);
static PREWARM_ATTEMPTS: AtomicU64 = AtomicU64::new(0);
/// Highest storefront pointer observed at hub time (0 = never non-null yet). Logged
/// so a failed pre-warm can be attributed to "storefront not up at hub" vs "fired
/// but the response did not land before screen-show".
static PREWARM_STOREFRONT_SEEN: AtomicUsize = AtomicUsize::new(0);

/// Pure pre-warm decision, isolated for host tests.
///
/// Fire exactly once, and only once the storefront singleton is non-null; before
/// that, keep waiting (a null storefront early at the hub is expected).
fn should_prewarm(already_done: bool, storefront: usize) -> bool {
    !already_done && storefront != 0
}

/// Probe all six category tokens with the game's own gate and return a slot mask.
///
/// `FUN_180014df0` forwards its `this` to `FUN_180014380`, which discards it and
/// fetches the group container from a singleton, so a null `this` is exactly what
/// the native code effectively passes. Called only from the bind detour, where the
/// store subsystem is provably live.
unsafe fn gate_mask() -> u8 {
    let base = STORE_BASE.load(Ordering::Acquire);
    if base == 0 {
        return 0;
    }
    let Some(gate) = base.checked_add(HAS_CATEGORY_RVA) else {
        return 0;
    };
    let gate_fn: HasCategoryFn = core::mem::transmute(gate);
    let mut mask = 0u8;
    for (slot, index) in GATE_INDICES.iter().enumerate() {
        if gate_fn(core::ptr::null_mut(), *index) != 0 {
            mask |= 1 << slot;
        }
    }
    mask
}

/// Ask the game to load the purchase groups now, on the caller's (game) thread.
///
/// Called from the FUT event dispatcher so it runs on a real game thread well before
/// the store screen is ever shown — the same thread the store screen itself would use
/// for this call at entry. Fail-closed: base/signature/storefront all validated, at
/// most one request per process.
pub(crate) unsafe fn maybe_prewarm_groups() {
    if PREWARM_DONE.load(Ordering::Acquire) || !REPAIR_ENABLED.load(Ordering::Acquire) {
        return;
    }
    let base = STORE_BASE.load(Ordering::Acquire);
    if base == 0 || !crate::sbc_trace::valid_cards_image(base) {
        return;
    }
    let Some(storefront) = base
        .checked_add(STOREFRONT_GLOBAL_RVA)
        .and_then(|slot| crate::sbc_trace::guarded_usize(slot))
    else {
        return;
    };
    if storefront != 0 {
        PREWARM_STOREFRONT_SEEN.store(storefront, Ordering::Release);
    }
    if !should_prewarm(false, storefront) {
        // Storefront not up yet at the hub: keep waiting, do not consume the attempt.
        return;
    }
    let Some(request) = base.checked_add(REQUEST_GROUPS_RVA) else {
        return;
    };
    if !crate::sbc_trace::executable_range_in_image(base, request, REQUEST_GROUPS_SIGNATURE.len())
        || core::slice::from_raw_parts(request as *const u8, REQUEST_GROUPS_SIGNATURE.len())
            != REQUEST_GROUPS_SIGNATURE
    {
        return;
    }
    // Claim the single attempt before issuing it, so a re-entrant event can never
    // fire a second request.
    PREWARM_DONE.store(true, Ordering::Release);
    PREWARM_ATTEMPTS.fetch_add(1, Ordering::Relaxed);
    let request_fn: RequestGroupsFn = core::mem::transmute(request);
    request_fn(storefront as *mut c_void);
    crate::write_log(&format!(
        "STORE_TABS: pre-warmed purchase groups at hub (storefront={storefront:#x})\n"
    ));
}

unsafe fn restore_entry<const N: usize>(target: usize, original: &[u8; N]) -> bool {
    let mut old = 0u32;
    if VirtualProtect(target as _, N, PAGE_EXECUTE_READWRITE, &mut old) == 0 {
        return false;
    }
    core::ptr::copy_nonoverlapping(original.as_ptr(), target as *mut u8, N);
    let flushed = FlushInstructionCache(GetCurrentProcess(), target as _, N) != 0;
    let mut ignored = 0u32;
    flushed && VirtualProtect(target as _, N, old, &mut ignored) != 0
}

unsafe fn write_entry<const N: usize>(
    target: usize,
    destination: usize,
    original: &[u8; N],
) -> Result<(), bool> {
    let mut patch = [0x90u8; N];
    patch[..ABS_JUMP_LEN].copy_from_slice(&crate::sbc_trace::absolute_jump(destination));
    let mut old = 0u32;
    if VirtualProtect(target as _, N, PAGE_EXECUTE_READWRITE, &mut old) == 0 {
        return Err(true);
    }
    core::ptr::copy_nonoverlapping(patch.as_ptr(), target as *mut u8, N);
    let flushed = FlushInstructionCache(GetCurrentProcess(), target as _, N) != 0;
    let mut ignored = 0u32;
    if flushed && VirtualProtect(target as _, N, old, &mut ignored) != 0 {
        Ok(())
    } else {
        Err(restore_entry(target, original))
    }
}

/// Detour target for the native tab binder. Read-only sensor: records the gate mask
/// the framework's bind is about to act on, then runs the original unchanged. This is
/// the definitive measurement of whether the pre-warm populated the container in time.
unsafe extern "system" fn bind_wrapper(ctx: *mut c_void, panel: *mut c_void) -> *mut c_void {
    let mask = gate_mask();
    LAST_BIND_MASK.store(mask as u32, Ordering::Release);
    LAST_THREAD.store(GetCurrentThreadId() as usize, Ordering::Relaxed);
    BIND_ENTRIES.fetch_add(1, Ordering::AcqRel);
    let original: BindFn = core::mem::transmute(BIND_TRAMPOLINE.load(Ordering::Acquire));
    original(ctx, panel)
}

#[derive(Clone, Copy, Debug, Eq, PartialEq)]
enum InstallOutcome {
    Installed,
    CleanFailure,
    DegradedHookActive,
    DegradedProcessState,
    DegradedHookAndProcess,
}

unsafe fn install_hook(base: usize) -> InstallOutcome {
    let Some(bind) = crate::sbc_trace::target_va(base, BIND_RVA) else {
        return InstallOutcome::CleanFailure;
    };
    let Some(gate) = crate::sbc_trace::target_va(base, HAS_CATEGORY_RVA) else {
        return InstallOutcome::CleanFailure;
    };
    let Some(request) = crate::sbc_trace::target_va(base, REQUEST_GROUPS_RVA) else {
        return InstallOutcome::CleanFailure;
    };
    // Fingerprint the image and ALL THREE functions: the one we detour and the two we
    // call (gate probe, group request). A single mismatched byte aborts cleanly with
    // no write and no call.
    if !crate::sbc_trace::valid_cards_image(base)
        || !crate::sbc_trace::executable_range_in_image(base, bind, BIND_SIGNATURE.len())
        || !crate::sbc_trace::executable_range_in_image(base, gate, HAS_CATEGORY_SIGNATURE.len())
        || !crate::sbc_trace::executable_range_in_image(
            base,
            request,
            REQUEST_GROUPS_SIGNATURE.len(),
        )
        || core::slice::from_raw_parts(bind as *const u8, BIND_SIGNATURE.len()) != BIND_SIGNATURE
        || core::slice::from_raw_parts(gate as *const u8, HAS_CATEGORY_SIGNATURE.len())
            != HAS_CATEGORY_SIGNATURE
        || core::slice::from_raw_parts(request as *const u8, REQUEST_GROUPS_SIGNATURE.len())
            != REQUEST_GROUPS_SIGNATURE
    {
        return InstallOutcome::CleanFailure;
    }
    let mut pinned = core::ptr::null_mut();
    if GetModuleHandleExA(
        GET_MODULE_HANDLE_EX_FLAG_FROM_ADDRESS | GET_MODULE_HANDLE_EX_FLAG_PIN,
        bind as *const u8,
        &mut pinned,
    ) == 0
        || pinned as usize != base
    {
        return InstallOutcome::CleanFailure;
    }
    let Some(trampoline) = crate::sbc_trace::allocate_trampoline(bind, COPY_LEN) else {
        return InstallOutcome::CleanFailure;
    };
    BIND_TRAMPOLINE.store(trampoline, Ordering::Release);
    STORE_BASE.store(base, Ordering::Release);

    let Some(_gate_lock) = crate::sbc_trace::acquire_patch_installer_gate() else {
        VirtualFree(trampoline as _, 0, MEM_RELEASE);
        BIND_TRAMPOLINE.store(0, Ordering::Release);
        return InstallOutcome::CleanFailure;
    };
    let mut peers = match crate::sbc_trace::suspend_peers(bind, bind) {
        Ok(peers) => peers,
        Err(crate::sbc_trace::QuiesceFailure::Acquire) => {
            VirtualFree(trampoline as _, 0, MEM_RELEASE);
            BIND_TRAMPOLINE.store(0, Ordering::Release);
            return InstallOutcome::CleanFailure;
        }
        Err(crate::sbc_trace::QuiesceFailure::Resume) => {
            return InstallOutcome::DegradedProcessState;
        }
    };
    let final_valid = crate::sbc_trace::valid_cards_image(base)
        && core::slice::from_raw_parts(bind as *const u8, BIND_SIGNATURE.len()) == BIND_SIGNATURE;
    let transaction = if !final_valid {
        InstallOutcome::CleanFailure
    } else {
        match write_entry(bind, bind_wrapper as *const () as usize, &BIND_SIGNATURE) {
            Ok(()) => InstallOutcome::Installed,
            Err(true) => InstallOutcome::CleanFailure,
            Err(false) => InstallOutcome::DegradedHookActive,
        }
    };
    let resumed = peers.resume_all();
    let outcome = if resumed {
        transaction
    } else if matches!(
        transaction,
        InstallOutcome::Installed | InstallOutcome::DegradedHookActive
    ) {
        InstallOutcome::DegradedHookAndProcess
    } else {
        InstallOutcome::DegradedProcessState
    };
    if outcome == InstallOutcome::CleanFailure {
        VirtualFree(trampoline as _, 0, MEM_RELEASE);
        BIND_TRAMPOLINE.store(0, Ordering::Release);
    }
    outcome
}

unsafe fn worker() {
    let _pending = crate::sbc_trace::CodeInstallerPending;
    let mut base = 0usize;
    for _ in 0..600u32 {
        base = GetModuleHandleA(c"CardsDLL_Win64_retail.dll".as_ptr().cast()) as usize;
        if base != 0 {
            break;
        }
        std::thread::sleep(std::time::Duration::from_millis(500));
    }
    let outcome = if base == 0 {
        InstallOutcome::CleanFailure
    } else {
        install_hook(base)
    };
    drop(_pending);
    match outcome {
        InstallOutcome::Installed => {
            crate::write_log("STORE_TABS: bind sensor + pre-warm installed (promoted)\n")
        }
        InstallOutcome::CleanFailure => {
            crate::write_log("STORE_TABS: clean install failure; inactive\n");
            return;
        }
        InstallOutcome::DegradedHookActive => {
            crate::write_log("STORE_TABS: DEGRADED hook may be active; terminate game now\n");
            return;
        }
        InstallOutcome::DegradedProcessState => {
            crate::write_log("STORE_TABS: DEGRADED thread state; terminate game now\n");
            return;
        }
        InstallOutcome::DegradedHookAndProcess => {
            crate::write_log("STORE_TABS: DEGRADED hook and thread state; terminate game now\n");
            return;
        }
    }

    let mut binds_seen = 0u64;
    let mut reports = 0u8;
    while reports < 64 {
        std::thread::sleep(std::time::Duration::from_millis(250));
        let binds = BIND_ENTRIES.load(Ordering::Acquire);
        if binds != binds_seen {
            crate::write_log(&format!(
                "STORE_TABS: bind generation={} mask={:#04x} prewarm_fired={} storefront_seen={:#x} tid={}\n",
                binds,
                LAST_BIND_MASK.load(Ordering::Acquire),
                PREWARM_ATTEMPTS.load(Ordering::Acquire),
                PREWARM_STOREFRONT_SEEN.load(Ordering::Acquire),
                LAST_THREAD.load(Ordering::Relaxed),
            ));
            binds_seen = binds;
            reports += 1;
        }
    }
    crate::write_log("STORE_TABS: report cap reached; hook remains installed\n");
}

pub(crate) fn install() {
    // Promoted: armed by the build. No environment variable participates.
    REPAIR_ENABLED.store(REPAIR_PROMOTED, Ordering::Release);
    crate::write_log("STORE_TABS: bind sensor + pre-warm ARMED (promoted); strict signature gate\n");
    std::thread::spawn(|| unsafe { worker() });
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn gate_indices_match_the_native_slot_order() {
        // mypacks, bronze, silver, gold, special, points — the order FUN_18007e5e0
        // tests them in, which is NOT the index order of FUN_180014580's jump table.
        assert_eq!(GATE_INDICES, [0, 2, 3, 4, 5, 1]);
    }

    #[test]
    fn prewarms_once_the_storefront_is_up() {
        assert!(should_prewarm(false, 0x1000));
    }

    #[test]
    fn waits_while_the_storefront_is_still_null() {
        assert!(!should_prewarm(false, 0));
    }

    #[test]
    fn never_prewarms_twice() {
        assert!(!should_prewarm(true, 0x1000));
    }

    #[test]
    fn detour_signature_is_long_enough_for_the_absolute_jump() {
        assert!(BIND_SIGNATURE.len() >= ABS_JUMP_LEN);
        assert_eq!(COPY_LEN, BIND_SIGNATURE.len());
    }

    #[test]
    fn request_signature_covers_the_validated_prologue() {
        // 18 bytes: `push rdi; sub rsp,0x90; movq [rsp+0x20],-2`.
        assert_eq!(REQUEST_GROUPS_SIGNATURE.len(), 18);
    }
}