"""Schemas for `/imports` and `/instruments/pending`, per `docs/ai/import-contract.md`.

Two conventions the Flutter client depends on, both repeated from AGENTS.md because breaking
either one breaks the generated Dart rather than a test:

* money and quantities are `Money` / `MoneyOpt` — `Decimal` in Python, a string on the wire;
* every stable key (`broker`, `parse_status`, `kind`, `status`, `asset_class`) is a plain
  `str`, never an enum. `AssetClass.index` cannot exist as a Dart enum member (it collides
  with `Enum.index`) and one enum leaking out stops the whole client from compiling.
"""

from __future__ import annotations

from datetime import date, datetime
from typing import Literal

from pydantic import BaseModel, Field

from fintracker.api.schemas.common import Money, MoneyOpt


class AccountSuggestion(BaseModel):
    """A broker account the user may attach an import to when the report's number matched none."""

    id: int
    name: str
    broker: str | None
    """tinvest | sber | vtb | other"""
    source_id: str


class ImportCounts(BaseModel):
    lines: int
    events_total: int
    events_new: int
    """No `event` carries this row's `dedupe_key` yet."""
    events_duplicate: int
    """The key is already in the ledger: committing upserts, it does not insert."""
    events_shadow: int
    """Rows that will land as `shadow` — this feed is not the account's primary source."""
    events_pending: int
    """Rows whose instrument nobody recognises yet."""
    by_kind: dict[str, int]


class PendingInstrumentOut(BaseModel):
    id: int
    source: str
    source_key: str
    isin: str | None = None
    ticker: str | None = None
    board: str | None = None
    name: str | None = None
    currency: str | None = None
    asset_class_hint: str | None = None
    """share | bond | etf | fund | currency — the report's own wording, never applied alone."""
    occurrences: int
    sample_quantity: MoneyOpt = None
    sample_price: MoneyOpt = None
    status: str
    """pending | resolved | ignored"""
    instrument_id: int | None = None
    first_seen_file_id: int | None = None
    created_at: datetime | None = None


class ReconciliationPosition(BaseModel):
    instrument_id: int | None
    instrument_name: str
    ticker: str | None
    isin: str | None
    qty_report: Money
    qty_derived: MoneyOpt
    """Null when the account is unknown or its lots were never rebuilt — never a zero."""
    qty_delta: MoneyOpt
    matches: bool


class ReconciliationCash(BaseModel):
    currency: str
    balance_report: Money
    balance_derived: MoneyOpt
    delta: MoneyOpt
    matches: bool


class ReconciliationOut(BaseModel):
    as_of: date | None
    positions: list[ReconciliationPosition] = Field(default_factory=list)
    cash: list[ReconciliationCash] = Field(default_factory=list)
    matches: bool = True


class SampleEventOut(BaseModel):
    line_no: int
    kind: str
    """buy | sell | dividend | coupon | … — the `EventKind` value as a string."""
    trade_date: date
    settle_date: date | None = None
    instrument_key: str | None = None
    instrument_name: str | None = None
    instrument_id: int | None = None
    quantity: MoneyOpt = None
    price: MoneyOpt = None
    amount: Money
    currency: str
    fee: MoneyOpt = None
    trade_no: str | None = None
    dedupe_key: str
    is_duplicate: bool
    description: str | None = None


class ImportSummary(BaseModel):
    """One import without the heavy parts — what `GET /imports` lists."""

    id: int
    broker: str
    """sber | vtb | csv"""
    filename: str
    sha256: str
    size_bytes: int
    parser_name: str | None = None
    parser_version: str | None = None
    parse_status: str
    """uploaded | parsed | committed | failed"""
    error: str | None = None
    duplicate_of_id: int | None = None
    """Not null ⇒ these bytes were already uploaded, and this is that import."""
    account_external_id: str | None = None
    account_id: int | None = None
    """Null ⇒ the account is unknown and commit is refused."""
    account_name: str | None = None
    period_from: date | None = None
    period_to: date | None = None
    uploaded_at: datetime | None = None
    committed_at: datetime | None = None
    counts: ImportCounts


class ImportPreview(ImportSummary):
    """The full preview: `POST /imports` and `GET /imports/{id}` both return this."""

    account_suggestions: list[AccountSuggestion] = Field(default_factory=list)
    pending_instruments: list[PendingInstrumentOut] = Field(default_factory=list)
    reconciliation: ReconciliationOut
    warnings: list[str] = Field(default_factory=list)
    sample_events: list[SampleEventOut] = Field(default_factory=list)


class CommitRequest(BaseModel):
    account_id: int | None = None
    """Needed only when the preview could not work the account out on its own."""
    confirm_duplicates: bool = False
    dry_run: bool = False


class ImportResult(BaseModel):
    import_id: int
    committed: bool
    events_created: int
    events_updated: int
    events_skipped: int
    """Rows still waiting on a `pending_instrument`."""
    events_shadow: int
    pending_instruments: int
    reconciliation: ReconciliationOut
    metrics_refreshed: bool


class NewInstrument(BaseModel):
    """The instrument to create from a report's own data (`action = "create"`)."""

    asset_class: str
    """share | bond | etf | fund | currency | index | deposit | real_estate | crypto | custom"""
    name: str
    currency: str = "RUB"
    isin: str | None = None
    ticker: str | None = None
    board: str | None = None
    lot: int = 1


class PendingResolveRequest(BaseModel):
    action: Literal["link", "create", "ignore"]
    instrument_id: int | None = None
    """Required for `link`."""
    instrument: NewInstrument | None = None
    """Required for `create`."""


class PendingResolveResult(BaseModel):
    id: int
    status: str
    """resolved | ignored"""
    instrument_id: int | None = None
    events_bound: int
    """How many events left `pending` for `confirmed`/`shadow`."""
    alias_created: bool
    metrics_refreshed: bool