"""D3 finance API — /finance/v1, deterministic, torch-free, dormant unless enabled.

Mounted only when ``AMANPAY_D3_ENABLED=1`` (see ``api/main.py``). The runtime (shared D2 store,
finance services) is built during startup and injected here; nothing in this module opens a
database, connects to a bucket, or runs at import time.

Security boundaries enforced here (reusing the D2 identity plumbing — no parallel systems):
* the actor/tenant come from the SESSION COOKIE, never client input;
* state-changing requests require a matching ``X-CSRF-Token``;
* operator routes require ``role == 'operator'``;
* sensitive actions require a recent passkey step-up (D2 recent-auth), surfaced as 422
  ``step_up_required`` so the frontend runs the D2 step-up ceremony and retries;
* responses are safe projections; errors are normalized reason tokens (never disclose existence).
"""

from __future__ import annotations

import time
from typing import Optional

from fastapi import APIRouter, Body, Request, Response
from fastapi.responses import JSONResponse

from amanpay.finance.errors import D3Error, status_for
from amanpay.finance.money import MoneyError, parse_amount_input
from amanpay.finance.receipts import build_receipt, transaction_view
from amanpay.identity.errors import D2Error
from amanpay.identity.errors import status_for as d2_status_for
from amanpay.identity.sessions import SESSION_COOKIE
from api.auth import rate_limit

router = APIRouter(prefix="/finance/v1", tags=["finance"])

_RUNTIME = None


def set_runtime(runtime) -> None:
    global _RUNTIME
    _RUNTIME = runtime


def _rt():
    if _RUNTIME is None:
        raise D3Error("not_found")
    return _RUNTIME


def install_error_handler(app) -> None:
    """Register D3Error (and D2Error, since D3 reuses D2 auth) -> normalized HTTP."""
    @app.exception_handler(D3Error)
    async def _d3_handler(_request: Request, exc: D3Error):        # noqa: ANN202
        token = str(exc)
        return JSONResponse(status_code=status_for(token), content={"detail": token})

    # D3 reuses D2 auth; translate D2Error too if D2's handler is not already installed.
    if not any(getattr(h, "__name__", "") == "_d2_error_handler"
               for h in getattr(app, "exception_handlers", {}).values()):
        @app.exception_handler(D2Error)
        async def _d2_handler(_request: Request, exc: D2Error):     # noqa: ANN202
            token = str(exc)
            return JSONResponse(status_code=d2_status_for(token), content={"detail": token})


# --------------------------------------------------------------------- helpers
def _cookie(request: Request) -> Optional[str]:
    return request.cookies.get(SESSION_COOKIE)


def _authed(request: Request):
    return _rt().identity.authenticate_request(_cookie(request))


def _require_csrf(request: Request, session) -> None:
    _rt().identity.require_csrf(session, request.headers.get("x-csrf-token"))


def _operator(request: Request):
    sess, user = _authed(request)
    if user.role != "operator" or user.status != "active":
        raise D3Error("not_operator")
    return sess, user


def _recent_auth_ok(session) -> bool:
    return (time.time() - session.last_auth_at) <= _rt().config.step_up_max_age_seconds


def _amount_minor(body: dict, currency: str = "SAR") -> int:
    """Normalize + validate a client amount at the boundary (string or amount_minor int)."""
    if "amount_minor" in body and body["amount_minor"] is not None:
        raw = body["amount_minor"]
        if isinstance(raw, bool) or not isinstance(raw, int):
            raise D3Error("amount_not_integer_minor")
        from amanpay.finance.money import validate_minor
        mv = validate_minor(raw, currency)
        if mv.minor <= 0:
            raise D3Error("amount_must_be_positive")
        return mv.minor
    try:
        return parse_amount_input(body.get("amount", ""), currency).minor
    except MoneyError as e:
        raise D3Error(str(e))


# ================================================================= status
@router.get("/status")
def status() -> dict:
    rt = _RUNTIME
    if rt is None:
        return {"enabled": False, "ready": False}
    rr = rt.store.runtime_report()
    return {"enabled": True, "ready": True, "persistent": rt.persistent,
            "default_currency": rt.config.default_currency,
            "journal_mode": rr.get("journal_mode"), "wal_status": rr.get("wal_status"),
            "max_transfer_minor": rt.config.max_transfer_minor,
            "max_daily_outflow_minor": rt.config.max_daily_outflow_minor,
            "simulation_only": True}


# ================================================================= accounts
@router.get("/accounts")
def list_accounts(request: Request) -> dict:
    _sess, user = _authed(request)
    return {"accounts": _rt().accounts.list_for_user(user.tenant_id, user.id)}


@router.get("/accounts/{account_id}")
def get_account(request: Request, account_id: str) -> dict:
    _sess, user = _authed(request)
    acct = _rt().accounts.require_owned(user.tenant_id, user.id, account_id)
    return {"account": _rt().accounts.view(acct)}


@router.get("/accounts/{account_id}/balance")
def account_balance(request: Request, account_id: str) -> dict:
    _sess, user = _authed(request)
    acct = _rt().accounts.require_owned(user.tenant_id, user.id, account_id)
    return {"balance": _rt().ledger.balances_for_financial_account(acct),
            "simulation_only": True}


@router.get("/accounts/{account_id}/transactions")
def account_transactions(request: Request, account_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    rt.accounts.require_owned(user.tenant_id, user.id, account_id)
    txns = rt.repo.list_transactions_for_account(user.tenant_id, account_id)
    return {"transactions": [transaction_view(rt.repo, t) for t in txns]}


# ============================================================= transactions
@router.get("/transactions")
def list_transactions(request: Request) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    txns = rt.repo.list_transactions_for_user(user.tenant_id, user.id)
    return {"transactions": [transaction_view(rt.repo, t) for t in txns]}


def _require_visible_txn(rt, user, txn_id):
    txn = rt.repo.get_transaction(user.tenant_id, txn_id)
    if txn is None:
        raise D3Error("transaction_not_found")
    if txn.initiated_by_user_id == user.id:
        return txn
    # Also visible to the owner of the source/destination account.
    for aid in (txn.source_financial_account_id, txn.dest_financial_account_id):
        if aid:
            fa = rt.repo.get_financial_account(user.tenant_id, aid)
            if fa and fa.owner_type == "customer" and fa.owner_user_id == user.id:
                return txn
    raise D3Error("transaction_not_found")


@router.get("/transactions/{txn_id}")
def get_transaction(request: Request, txn_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    txn = _require_visible_txn(rt, user, txn_id)
    return {"transaction": transaction_view(rt.repo, txn)}


@router.get("/transactions/{txn_id}/receipt")
def get_receipt(request: Request, txn_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    txn = _require_visible_txn(rt, user, txn_id)
    return {"receipt": build_receipt(rt.repo, txn)}


# ============================================================ own transfers
@router.post("/transfers/own/options")
def own_options(request: Request) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    return {"accounts": rt.accounts.list_for_user(user.tenant_id, user.id),
            "max_transfer_minor": rt.config.max_transfer_minor,
            "step_up_threshold_minor": rt.config.step_up_threshold_minor}


@router.post("/transfers/own/submit")
def own_submit(request: Request, body: dict = Body(...)) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_transfer", capacity=10, refill_per_sec=0.5)
    txn = rt.transfers.own_transfer(
        tenant_id=user.tenant_id, user_id=user.id, actor_role=user.role,
        source_id=str(body.get("source_account_id", "")), dest_id=str(body.get("dest_account_id", "")),
        amount_minor=_amount_minor(body), note=str(body.get("note", "")),
        recent_auth_ok=_recent_auth_ok(sess), idempotency_key=body.get("idempotency_key"))
    return {"transaction": transaction_view(rt.repo, txn), "receipt": build_receipt(rt.repo, txn)}


# =================================================================== p2p
@router.post("/recipients/resolve")
def resolve_recipient(request: Request, body: dict = Body(...)) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    rate_limit(request, "d3_recipient", capacity=8, refill_per_sec=0.2)
    return {"recipient": rt.transfers.resolve_recipient(
        tenant_id=user.tenant_id, actor_user_id=user.id, handle=str(body.get("handle", "")))}


@router.post("/transfers/p2p/options")
def p2p_options(request: Request, body: dict = Body(...)) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    rate_limit(request, "d3_recipient", capacity=8, refill_per_sec=0.2)
    recipient = rt.transfers.resolve_recipient(
        tenant_id=user.tenant_id, actor_user_id=user.id, handle=str(body.get("handle", "")))
    return {"recipient": recipient, "accounts": rt.accounts.list_for_user(user.tenant_id, user.id),
            "max_transfer_minor": rt.config.max_transfer_minor}


@router.post("/transfers/p2p/submit")
def p2p_submit(request: Request, body: dict = Body(...)) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_transfer", capacity=10, refill_per_sec=0.5)
    txn = rt.transfers.p2p_transfer(
        tenant_id=user.tenant_id, user_id=user.id, actor_role=user.role,
        source_id=str(body.get("source_account_id", "")),
        recipient_handle=str(body.get("handle", "")), amount_minor=_amount_minor(body),
        note=str(body.get("note", "")), recent_auth_ok=_recent_auth_ok(sess),
        idempotency_key=body.get("idempotency_key"))
    return {"transaction": transaction_view(rt.repo, txn), "receipt": build_receipt(rt.repo, txn)}


# ============================================================== merchants
@router.get("/merchants")
def list_merchants(request: Request) -> dict:
    rt = _rt()
    _authed(request)
    _sess, user = _authed(request)
    return {"merchants": rt.merchants.list_directory(user.tenant_id)}


@router.get("/merchants/{merchant_id}")
def merchant_detail(request: Request, merchant_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    return {"merchant": rt.merchants.view(rt.merchants.get_active(user.tenant_id, merchant_id))}


@router.post("/merchants/{merchant_id}/payment-options")
def merchant_payment_options(request: Request, merchant_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    mch = rt.merchants.get_active(user.tenant_id, merchant_id)
    return {"merchant": rt.merchants.view(mch),
            "accounts": rt.accounts.list_for_user(user.tenant_id, user.id),
            "max_transfer_minor": rt.config.max_transfer_minor}


@router.post("/merchants/{merchant_id}/payments")
def merchant_pay(request: Request, merchant_id: str, body: dict = Body(...)) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_merchant_pay", capacity=10, refill_per_sec=0.5)
    txn = rt.merchants.pay(
        tenant_id=user.tenant_id, user_id=user.id, actor_role=user.role,
        source_id=str(body.get("source_account_id", "")), merchant_id=merchant_id,
        amount_minor=_amount_minor(body), note=str(body.get("note", "")),
        recent_auth_ok=_recent_auth_ok(sess), idempotency_key=body.get("idempotency_key"))
    return {"transaction": transaction_view(rt.repo, txn), "receipt": build_receipt(rt.repo, txn)}


@router.post("/merchant/transactions/{transaction_id}/refunds")
def merchant_refund(request: Request, transaction_id: str, body: dict = Body(...)) -> dict:
    rt = _rt()
    sess, user = _operator(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_refund", capacity=6, refill_per_sec=0.1)
    txn = rt.merchants.refund(
        tenant_id=user.tenant_id, operator_user_id=user.id,
        merchant_id=str(body.get("merchant_id", "")), transaction_id=transaction_id,
        amount_minor=_amount_minor(body), recent_auth_ok=_recent_auth_ok(sess),
        idempotency_key=body.get("idempotency_key"))
    return {"transaction": transaction_view(rt.repo, txn), "receipt": build_receipt(rt.repo, txn)}


# =================================================================== ATM
@router.post("/atm/deposits")
def atm_initiate(request: Request, body: dict = Body(...)) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_atm", capacity=6, refill_per_sec=0.2)
    dep = rt.atm.initiate(
        tenant_id=user.tenant_id, customer_user_id=user.id,
        destination_account_id=str(body.get("destination_account_id", "")),
        amount_minor=_amount_minor(body), kiosk_ref=str(body.get("kiosk_ref", "")),
        idempotency_key=body.get("idempotency_key"))
    return {"deposit": rt.atm.view(dep)}


@router.get("/atm/deposits/{deposit_id}")
def atm_get(request: Request, deposit_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    dep = rt.repo.get_atm_deposit(user.tenant_id, deposit_id)
    if dep is None or (dep.customer_user_id != user.id and user.role != "operator"):
        raise D3Error("deposit_not_found")
    return {"deposit": rt.atm.view(dep, for_operator=(user.role == "operator"))}


@router.post("/atm/deposits/{deposit_id}/customer-confirm")
def atm_customer_confirm(request: Request, deposit_id: str) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    dep = rt.atm.customer_confirm(tenant_id=user.tenant_id, customer_user_id=user.id,
                                  deposit_id=deposit_id)
    return {"deposit": rt.atm.view(dep)}


@router.post("/operator/atm/deposits/{deposit_id}/confirm")
def atm_operator_confirm(request: Request, deposit_id: str) -> dict:
    rt = _rt()
    sess, user = _operator(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_atm_confirm", capacity=10, refill_per_sec=0.3)
    txn = rt.atm.operator_confirm(tenant_id=user.tenant_id, operator_user_id=user.id,
                                  deposit_id=deposit_id, recent_auth_ok=_recent_auth_ok(sess))
    return {"transaction": transaction_view(rt.repo, txn), "receipt": build_receipt(rt.repo, txn)}


@router.post("/operator/atm/deposits/{deposit_id}/reject")
def atm_operator_reject(request: Request, deposit_id: str) -> dict:
    rt = _rt()
    sess, user = _operator(request)
    _require_csrf(request, sess)
    dep = rt.atm.operator_reject(tenant_id=user.tenant_id, operator_user_id=user.id,
                                 deposit_id=deposit_id)
    return {"deposit": rt.atm.view(dep, for_operator=True)}


# ============================================================ intent assistant
@router.post("/intents")
@router.post("/intent-assistant/parse")
def intent_parse(request: Request, body: dict = Body(default={})) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_intent", capacity=12, refill_per_sec=0.5)
    return {"intent": rt.intents.parse(tenant_id=user.tenant_id, user_id=user.id,
                                       text=str((body or {}).get("text", "")),
                                       origin=str((body or {}).get("origin", "text")))}


@router.get("/intents/{intent_id}")
def intent_get(request: Request, intent_id: str) -> dict:
    rt = _rt()
    _sess, user = _authed(request)
    intent = rt.intents.get(user.tenant_id, user.id, intent_id)
    return {"intent": rt.intents.view(intent)}


@router.post("/intent-assistant/{intent_id}/clarify")
def intent_clarify(request: Request, intent_id: str, body: dict = Body(...)) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    return {"intent": rt.intents.clarify(
        tenant_id=user.tenant_id, user_id=user.id, intent_id=intent_id,
        amount_input=body.get("amount"), recipient_ref=body.get("handle"),
        source_account_id=body.get("source_account_id"), note=body.get("note"))}


@router.post("/intent-assistant/{intent_id}/prepare")
def intent_prepare(request: Request, intent_id: str) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    return {"intent": rt.intents.prepare(tenant_id=user.tenant_id, user_id=user.id,
                                         intent_id=intent_id)}


@router.post("/intents/{intent_id}/confirm")
def intent_confirm(request: Request, intent_id: str, body: dict = Body(default={})) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    rate_limit(request, "d3_transfer", capacity=10, refill_per_sec=0.5)
    txn = rt.intents.confirm(
        tenant_id=user.tenant_id, user_id=user.id, actor_role=user.role, intent_id=intent_id,
        recent_auth_ok=_recent_auth_ok(sess),
        source_account_id=(body or {}).get("source_account_id"),
        dest_account_id=(body or {}).get("dest_account_id"))
    return {"transaction": transaction_view(rt.repo, txn), "receipt": build_receipt(rt.repo, txn)}


@router.post("/intents/{intent_id}/cancel")
def intent_cancel(request: Request, intent_id: str) -> dict:
    rt = _rt()
    sess, user = _authed(request)
    _require_csrf(request, sess)
    return rt.intents.cancel(tenant_id=user.tenant_id, user_id=user.id, intent_id=intent_id)


# =============================================================== operator
@router.get("/operator/transactions")
def op_transactions(request: Request) -> dict:
    rt = _rt()
    _sess, user = _operator(request)
    return {"transactions": [transaction_view(rt.repo, t)
                             for t in rt.repo.list_transactions_for_tenant(user.tenant_id)]}


@router.get("/operator/holds")
def op_holds(request: Request) -> dict:
    rt = _rt()
    _sess, user = _operator(request)
    holds = rt.repo.list_holds_for_operator(user.tenant_id, state="active")
    return {"holds": [{"id": h.id, "financial_account_id": h.financial_account_id,
                       "amount_minor": h.amount_minor, "currency": h.currency, "state": h.state,
                       "expires_at": h.expires_at} for h in holds]}


@router.get("/operator/atm/deposits")
def op_atm_deposits(request: Request) -> dict:
    rt = _rt()
    _sess, user = _operator(request)
    deps = rt.repo.list_atm_deposits(user.tenant_id, state="awaiting_operator_confirmation")
    return {"deposits": [rt.atm.view(d, for_operator=True) for d in deps]}


@router.get("/operator/ledger/health")
def op_ledger_health(request: Request) -> dict:
    rt = _rt()
    _sess, user = _operator(request)
    from amanpay.finance.verification import verify_ledger
    return verify_ledger(rt.store, user.tenant_id)