from __future__ import annotations

import json
from collections.abc import Iterable
from pathlib import Path
from typing import Any

import httpx

from broker_sync.models import Account, Activity

_LOGIN_PATH = "/api/v1/auth/login"
_ACCOUNTS_PATH = "/api/v1/accounts"
_IMPORT_CHECK = "/api/v1/activities/import/check"
_IMPORT_REAL = "/api/v1/activities/import"


class WealthfolioError(Exception):
    pass


class WealthfolioUnauthorizedError(WealthfolioError):
    """Raised when login itself fails (bad creds or Wealthfolio down).

    Distinct from a 401 on a random endpoint — those trigger an
    automatic re-login attempt.
    """


class ImportValidationError(WealthfolioError):
    """`/activities/import/check` returned a non-2xx. We never reach the real import."""


class WealthfolioSink:
    """Push canonical Activities to Wealthfolio via its CSV import endpoint.

    Auth is JWT-cookie via POST /api/v1/auth/login. Cookies are persisted
    to disk so CronJob pods can reuse them across runs (Wealthfolio's
    /auth/login is 5-req/min rate-limited).

    Not multi-process safe — file locking is added in Phase 1 when we
    fan out to multiple CronJobs.
    """

    def __init__(
        self,
        *,
        base_url: str,
        username: str,
        password: str,
        session_path: Path | str,
        transport: httpx.AsyncBaseTransport | None = None,
    ) -> None:
        self._username = username
        self._password = password
        self._session_path = Path(session_path)
        self._client = httpx.AsyncClient(
            base_url=base_url.rstrip("/"),
            timeout=30.0,
            transport=transport,
        )

    async def close(self) -> None:
        await self._client.aclose()

    # -- session --

    def _load_cookies(self) -> dict[str, str]:
        if not self._session_path.exists():
            return {}
        raw = json.loads(self._session_path.read_text())
        got = raw.get("cookies", {})
        assert isinstance(got, dict)
        return got

    def _save_cookies(self, cookies: dict[str, str]) -> None:
        self._session_path.parent.mkdir(parents=True, exist_ok=True)
        self._session_path.write_text(json.dumps({"cookies": cookies}))

    async def login(self) -> None:
        # Wealthfolio 3.2's LoginRequest is `{ password: String }` only — a
        # username key is rejected as an unknown field (HTTP 400). The
        # `username` constructor arg is kept for a future Wealthfolio
        # release that may add multi-user support.
        resp = await self._client.post(
            _LOGIN_PATH,
            json={"password": self._password},
        )
        if resp.status_code == 401:
            raise WealthfolioUnauthorizedError("Wealthfolio /auth/login returned 401")
        resp.raise_for_status()
        cookies = dict(resp.cookies.items())
        if not cookies:
            raise WealthfolioError("/auth/login returned 2xx but no Set-Cookie")
        self._save_cookies(cookies)

    @staticmethod
    def _cookie_header(cookies: dict[str, str]) -> str:
        return "; ".join(f"{k}={v}" for k, v in cookies.items())

    async def _request(self, method: str, path: str, **kw: Any) -> httpx.Response:
        cookies = self._load_cookies()
        headers = dict(kw.pop("headers", {}) or {})
        if cookies:
            headers["Cookie"] = self._cookie_header(cookies)
        resp = await self._client.request(method, path, headers=headers, **kw)
        if resp.status_code == 401 and path != _LOGIN_PATH:
            await self.login()
            cookies = self._load_cookies()
            headers["Cookie"] = self._cookie_header(cookies)
            resp = await self._client.request(method, path, headers=headers, **kw)
        return resp

    # -- accounts --

    async def list_accounts(self) -> list[dict[str, Any]]:
        resp = await self._request("GET", _ACCOUNTS_PATH)
        resp.raise_for_status()
        raw = resp.json()
        assert isinstance(raw, list)
        return raw

    async def ensure_account(self, account: Account) -> str:
        """Idempotently create the account and return Wealthfolio's UUID for it.

        Wealthfolio generates its own UUIDs on POST /accounts, ignoring any
        `id` we supply. We identify accounts by (provider, providerAccountId)
        which Wealthfolio DOES preserve verbatim. Our own Account.id is
        used as the providerAccountId.
        """
        existing = await self.list_accounts()
        for a in existing:
            if (a.get("provider") == account.provider and a.get("providerAccountId") == account.id):
                wf_id = a.get("id")
                assert isinstance(wf_id, str)
                return wf_id

        # NewAccount is camelCase with required booleans.
        # See apps/server/src/models.rs#NewAccount.
        resp = await self._request(
            "POST",
            _ACCOUNTS_PATH,
            json={
                "name": account.name,
                "accountType": str(account.account_type),
                "currency": account.currency,
                "isDefault": False,
                "isActive": True,
                "isArchived": False,
                "trackingMode": "TRANSACTIONS",
                "provider": account.provider,
                "providerAccountId": account.id,
            },
        )
        resp.raise_for_status()
        created = resp.json()
        wf_id = created.get("id")
        if not isinstance(wf_id, str):
            raise WealthfolioError(f"POST /accounts returned no id: {created}")
        return wf_id

    # -- activity import --

    @staticmethod
    def _activity_to_import_row(a: Activity) -> dict[str, Any]:
        """Match Wealthfolio's ActivityImport struct (camelCase JSON)."""
        row: dict[str, Any] = {
            "date": a.date.isoformat(),
            "symbol": a.symbol or "$CASH",
            "activityType": str(a.activity_type),
            "currency": a.currency,
            "accountId": a.account_id,
            # Required booleans on ActivityImport (no defaults in Rust struct).
            "isDraft": False,
            "isValid": True,
        }
        if a.quantity is not None:
            row["quantity"] = format(a.quantity, "f")
        if a.unit_price is not None:
            row["unitPrice"] = format(a.unit_price, "f")
        if a.amount is not None:
            row["amount"] = format(a.amount, "f")
        if a.fee:
            row["fee"] = format(a.fee, "f")
        if a.notes:
            row["comment"] = a.notes
        return row

    async def import_activities(self, activities: Iterable[Activity]) -> list[dict[str, Any]]:
        rows = [self._activity_to_import_row(a) for a in activities]
        if not rows:
            return []

        # Step 1 — /import/check hydrates each row with resolved asset_id,
        # exchange_mic, quote_ccy, instrument_type, quote_mode (and flags
        # errors). The /import endpoint on Wealthfolio 3.2+ DOES NOT
        # re-resolve — if we send the un-enriched row the activity is
        # silently dropped (import returns 200 OK with activities=[] in
        # the payload). We must feed check's output into import.
        check = await self._request("POST", _IMPORT_CHECK, json={"activities": rows})
        if check.status_code >= 400:
            try:
                payload = check.json()
            except Exception:
                payload = {"raw": check.text}
            raise ImportValidationError(f"Wealthfolio /import/check rejected: {payload}")

        checked = check.json()
        if not isinstance(checked, list):
            raise ImportValidationError(
                f"Wealthfolio /import/check returned non-list: {type(checked).__name__}")

        invalid = [r for r in checked if isinstance(r, dict) and r.get("errors")]
        if invalid:
            raise ImportValidationError(f"Wealthfolio /import/check flagged {len(invalid)} row(s); "
                                        f"first: {invalid[0]}")
        # Drop any row the server marked is_valid=false (shouldn't happen
        # without errors, but defensive).
        valid_rows = [r for r in checked if isinstance(r, dict) and r.get("isValid")]

        real = await self._request("POST", _IMPORT_REAL, json={"activities": valid_rows})
        real.raise_for_status()
        raw = real.json()
        if isinstance(raw, dict) and "activities" in raw:
            got = raw["activities"]
            assert isinstance(got, list)
        elif isinstance(raw, list):
            got = raw
        else:
            got = []
        # Silent-drop detection: if we sent N valid rows but got 0 back, something
        # is silently rejecting them (usually a date-format or asset-resolution
        # quirk that check() didn't catch). Raise so the pipeline records failure
        # instead of marking the rows as synced when they never landed.
        if valid_rows and not got:
            # Also surface any per-row `errors` or `warnings` from the check step
            # — those are often the best hint about why /import dropped them.
            first_warn = next(
                (r.get("warnings") for r in checked if isinstance(r, dict) and r.get("warnings")),
                None,
            )
            raise ImportValidationError(
                f"Wealthfolio /import silently dropped all {len(valid_rows)} rows. "
                f"First checked row: {checked[0] if checked else 'none'}. "
                f"First warning (if any): {first_warn}"
            )
        return got