//! FIFA 17 in-process TLS/certificate + store crash-guard compatibility.
//!
//! Ports the *proven* subset of the external `openfut-autopatch` patch set into
//! `version.dll`, so the client-local contract no longer needs an external
//! `/proc`-writing patcher. Two concerns, both fail-closed and one-shot:
//!
//!   1. ProtoSSL certificate gates in FIFA17.exe (REQUIRED_FOR_TLS) — let the
//!      TLS handshake against the OpenFUT bridge cert succeed. Present only after
//!      the STEAMPUNKS packer maps/decrypts the real code, so they are polled for.
//!   2. The empty-"My Packs" store resolver crash-guard in CardsDLL
//!      (REQUIRED_FOR_STORE_TLS, bug 6c) — CardsDLL loads lazily on entering UT,
//!      so it is applied once the module appears.
//!
//! Deliberately NOT ported: the eight unconditional `STORE_PATCHES` from the
//! external patcher. They carry no recovered original bytes (cannot be
//! fail-closed) and are re-applied every tick (would require the very
//! constant-rewrite loop this milestone forbids); the external patcher's own
//! source records no rationale for them. See the Vault ADR.
//!
//! Every address is ASLR-relocated from its preferred image base at runtime
//! (`live = module_base + (static_va - preferred_base)`); nothing patches an
//! absolute address. Every write goes through [`crate::patch_mem`]'s fail-closed
//! primitive: original → write+verify, already-patched → no-op, anything else →
//! logged and skipped.

use crate::patch_mem::{self, ApplyOutcome, Mem, PatchState, WinMem};
use crate::write_log;
use std::time::{Duration, Instant};

/// FIFA17.exe preferred image base (confirmed: futmem reports the client mapped
/// flat at this base; Wine honours it, native Windows ASLR may not — hence the
/// runtime-base + RVA model below).
const FIFA17_PREFERRED_BASE: u64 = 0x1_4000_0000;
/// CardsDLL_Win64_retail.dll preferred image base.
const CARDS_PREFERRED_BASE: u64 = 0x1_8000_0000;

/// Which module a site lives in.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
enum Module {
    Fifa17Exe,
    CardsDll,
}

impl Module {
    const fn preferred_base(self) -> u64 {
        match self {
            Module::Fifa17Exe => FIFA17_PREFERRED_BASE,
            Module::CardsDll => CARDS_PREFERRED_BASE,
        }
    }

    /// Runtime base of the loaded module, or `None` if not mapped yet. FIFA17.exe
    /// is the main image (null name); CardsDLL is resolved by its retail name.
    unsafe fn runtime_base(self) -> Option<usize> {
        match self {
            Module::Fifa17Exe => patch_mem::module_base(core::ptr::null()),
            Module::CardsDll => {
                patch_mem::module_base(c"CardsDLL_Win64_retail.dll".as_ptr().cast())
                    .or_else(|| patch_mem::module_base(c"CardsDLL.dll".as_ptr().cast()))
            }
        }
    }
}

/// One fail-closed byte patch, expressed as a static VA in its module's preferred
/// image so the derivation `RVA = VA - preferred_base` is auditable.
struct Site {
    module: Module,
    static_va: u64,
    orig: &'static [u8],
    patch: &'static [u8],
    label: &'static str,
}

impl Site {
    const fn rva(&self) -> u64 {
        patch_mem::rva(self.static_va, self.module.preferred_base())
    }
    fn live_addr(&self, base: usize) -> usize {
        patch_mem::live_addr(base, self.rva())
    }
}

// ── ProtoSSL certificate gates (FIFA17.exe) — REQUIRED_FOR_TLS ──────────────────
// GATE1: JNZ rel32 -> 6×NOP (fall through the cert-verify failure branch).
// GATE2: function prologue -> `xor eax,eax; ret` (cert-verify returns 0/false).
// Applied as a pair, exactly like the external patcher: written only when BOTH
// read their known original, treated as done when BOTH already hold the patch.
const GATE1: Site = Site {
    module: Module::Fifa17Exe,
    static_va: 0x1_4613_2548,
    orig: &[0x0f, 0x85, 0x76, 0x01, 0x00, 0x00],
    patch: &[0x90, 0x90, 0x90, 0x90, 0x90, 0x90],
    label: "GATE1",
};
const GATE2: Site = Site {
    module: Module::Fifa17Exe,
    static_va: 0x1_4613_61b0,
    orig: &[0x48, 0x89, 0x5c],
    patch: &[0x31, 0xc0, 0xc3],
    label: "GATE2",
};

// ── Empty "My Packs" store resolver crash-guard (CardsDLL) — REQUIRED_FOR_STORE_TLS
// JNZ 0x14869 (75 0f) -> JG 0x14869 (7f 0f): routes zero/negative store category
// ids through the Browse path instead of a NULL deref. Fail-closed one-shot.
const STORE_GUARD: Site = Site {
    module: Module::CardsDll,
    static_va: 0x1_8001_4858,
    orig: &[0x75, 0x0f],
    patch: &[0x7f, 0x0f],
    label: "empty-mypacks-store-guard",
};

/// Poll cadence while waiting for the packer to unpack / CardsDLL to load. Low
/// frequency: the thread sleeps between ticks, so idle CPU is negligible.
const POLL: Duration = Duration::from_millis(250);
/// Upper bound on the whole worker's lifetime so it can never spin forever if the
/// user never enters Ultimate Team (CardsDLL never loads).
const MAX_WAIT: Duration = Duration::from_secs(15 * 60);

/// Decision for the FIFA17.exe cert-gate pair.
#[derive(Clone, Copy, PartialEq, Eq, Debug)]
enum CertAction {
    /// Not both readable yet, or a mixed/unrecognised state — keep polling.
    Wait,
    /// Both gates hold their known original — safe to apply the pair.
    Apply,
    /// Both gates already hold the patch — nothing to do.
    Done,
}

/// Pure pairing rule (unit-tested): only act when both gates agree.
fn cert_action(g1: Option<PatchState>, g2: Option<PatchState>) -> CertAction {
    match (g1, g2) {
        (Some(PatchState::AlreadyPatched), Some(PatchState::AlreadyPatched)) => CertAction::Done,
        (Some(PatchState::Original), Some(PatchState::Original)) => CertAction::Apply,
        _ => CertAction::Wait,
    }
}

/// Arm the FIFA17 TLS/store compatibility patcher: spawns a bounded background
/// worker so it never touches the loader lock and never blocks `install()`.
pub fn install() {
    std::thread::spawn(|| unsafe { worker() });
}

unsafe fn worker() {
    write_log("fifa17_tls: patch worker start\n");
    let mut mem = WinMem;
    let start = Instant::now();
    let mut cert_done = false;
    let mut guard_done = false;
    // Throttle the "still waiting" diagnostics to one line each.
    let mut logged_cert_wait = false;
    let mut logged_guard_wait = false;

    loop {
        if !cert_done {
            cert_done = try_cert_gates(&mut mem, &mut logged_cert_wait);
        }
        if !guard_done {
            match Module::CardsDll.runtime_base() {
                Some(cbase) => guard_done = try_store_guard(&mut mem, cbase),
                None => {
                    if !logged_guard_wait {
                        write_log("fifa17_tls: waiting for CardsDLL (enter Ultimate Team)\n");
                        logged_guard_wait = true;
                    }
                }
            }
        }
        if cert_done && guard_done {
            write_log("fifa17_tls: TLS patch set complete\n");
            return;
        }
        if start.elapsed() >= MAX_WAIT {
            write_log(&format!(
                "fifa17_tls: worker stop (timeout {MAX_WAIT:?}); cert_gates_done={cert_done} store_guard_done={guard_done}\n"
            ));
            return;
        }
        std::thread::sleep(POLL);
    }
}

/// Apply the FIFA17.exe cert-gate pair. Returns `true` once the pair is settled
/// (applied or already patched); `false` while still unpacking / not both ready.
unsafe fn try_cert_gates(mem: &mut WinMem, logged_wait: &mut bool) -> bool {
    let base = match Module::Fifa17Exe.runtime_base() {
        Some(b) => b,
        None => return false,
    };
    let g1_addr = GATE1.live_addr(base);
    let g2_addr = GATE2.live_addr(base);
    let g1 = patch_mem::read_state(mem, g1_addr, GATE1.orig, GATE1.patch);
    let g2 = patch_mem::read_state(mem, g2_addr, GATE2.orig, GATE2.patch);

    match cert_action(g1, g2) {
        CertAction::Done => {
            write_log("fifa17_tls: cert gates already patched\n");
            true
        }
        CertAction::Apply => {
            let o1 = patch_mem::apply_checked(mem, g1_addr, GATE1.orig, GATE1.patch);
            let o2 = patch_mem::apply_checked(mem, g2_addr, GATE2.orig, GATE2.patch);
            if o1.is_patched() && o2.is_patched() {
                write_log(&format!(
                    "fifa17_tls: PATCHED cert gates ({} @ {g1_addr:#x} {o1:?}; {} @ {g2_addr:#x} {o2:?})\n",
                    GATE1.label, GATE2.label
                ));
                true
            } else {
                write_log(&format!(
                    "fifa17_tls: cert gate write FAILED ({} {o1:?}; {} {o2:?}) — TLS NOT installed\n",
                    GATE1.label, GATE2.label
                ));
                // Terminal: a write/verify failure will not fix itself by retrying.
                true
            }
        }
        CertAction::Wait => {
            if !*logged_wait {
                write_log(&format!(
                    "fifa17_tls: cert gates not ready (still unpacking?) {}={g1:?} {}={g2:?}\n",
                    GATE1.label, GATE2.label
                ));
                *logged_wait = true;
            }
            false
        }
    }
}

/// Apply the CardsDLL store crash-guard once CardsDLL is mapped. Returns `true`
/// once the site is settled (its bytes are final the moment CardsDLL is loaded,
/// so any read outcome is a terminal decision — no further polling).
unsafe fn try_store_guard(mem: &mut WinMem, cbase: usize) -> bool {
    let addr = STORE_GUARD.live_addr(cbase);
    let outcome = patch_mem::apply_checked(mem, addr, STORE_GUARD.orig, STORE_GUARD.patch);
    match outcome {
        ApplyOutcome::NotReadable => false, // CardsDLL mapped but this page not yet — retry
        ApplyOutcome::Applied | ApplyOutcome::AlreadyPatched => {
            write_log(&format!(
                "fifa17_tls: store guard {} @ {addr:#x} {outcome:?} (VERIFIED empty-My-Packs)\n",
                STORE_GUARD.label
            ));
            true
        }
        ApplyOutcome::Mismatch => {
            let mut cur = [0u8; patch_mem::MAX_PATCH_LEN];
            let n = STORE_GUARD.patch.len();
            let seen = if mem.read(addr, &mut cur[..n]) {
                patch_mem::hex(&cur[..n])
            } else {
                "unreadable".into()
            };
            write_log(&format!(
                "fifa17_tls: SKIP store guard @ {addr:#x}: unexpected {seen} (build mismatch)\n"
            ));
            true
        }
        ApplyOutcome::WriteFailed | ApplyOutcome::VerifyFailed => {
            write_log(&format!(
                "fifa17_tls: store guard @ {addr:#x} {outcome:?}\n"
            ));
            true
        }
    }
}

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

    #[test]
    fn every_site_is_well_formed() {
        for s in [&GATE1, &GATE2, &STORE_GUARD] {
            assert_eq!(
                s.orig.len(),
                s.patch.len(),
                "{}: orig/patch length",
                s.label
            );
            assert!(!s.orig.is_empty(), "{}: empty", s.label);
            assert!(
                s.patch.len() <= patch_mem::MAX_PATCH_LEN,
                "{}: exceeds MAX_PATCH_LEN",
                s.label
            );
            assert_ne!(s.orig, s.patch, "{}: orig == patch", s.label);
        }
    }

    #[test]
    fn rvas_match_the_recovered_derivation() {
        assert_eq!(GATE1.rva(), 0x613_2548);
        assert_eq!(GATE2.rva(), 0x613_61b0);
        assert_eq!(STORE_GUARD.rva(), 0x1_4858);
    }

    #[test]
    fn live_addresses_track_the_runtime_base() {
        // At the preferred base the live address is the recorded static VA.
        assert_eq!(GATE1.live_addr(0x1_4000_0000), 0x1_4613_2548);
        assert_eq!(STORE_GUARD.live_addr(0x1_8000_0000), 0x1_8001_4858);
        // Relocated bases shift every site by the same delta.
        assert_eq!(GATE1.live_addr(0x3_0000_0000), 0x3_0613_2548);
    }

    #[test]
    fn cert_pair_only_acts_when_both_gates_agree() {
        use PatchState::*;
        assert_eq!(
            cert_action(Some(Original), Some(Original)),
            CertAction::Apply
        );
        assert_eq!(
            cert_action(Some(AlreadyPatched), Some(AlreadyPatched)),
            CertAction::Done
        );
        // Not yet unpacked / partial / mismatched => never a blind half-write.
        assert_eq!(cert_action(None, None), CertAction::Wait);
        assert_eq!(cert_action(Some(Original), None), CertAction::Wait);
        assert_eq!(
            cert_action(Some(Original), Some(AlreadyPatched)),
            CertAction::Wait
        );
        assert_eq!(
            cert_action(Some(Mismatch), Some(Mismatch)),
            CertAction::Wait
        );
    }
}