"""SQLAlchemy ORM models for month-end closing sessions and their results."""
from __future__ import annotations

import datetime as dt

from sqlalchemy import (
    Boolean, Column, Date, DateTime, Float, ForeignKey, Integer, String, Text, Index
)
from sqlalchemy.orm import relationship

from .database import Base


def _now() -> dt.datetime:
    return dt.datetime.utcnow()


class Session(Base):
    __tablename__ = "sessions"
    id = Column(Integer, primary_key=True)
    name = Column(String, nullable=False)
    reporting_month = Column(String)                 # "2026-01"
    month_end_date = Column(Date)
    reporting_currency = Column(String, default="USD")
    clearing_lag_days = Column(Integer, default=2)
    rounding_tolerance = Column(Float, default=0.01)
    allowance_for_returns = Column(Float, default=0.0)
    manual_adjustment = Column(Float, default=0.0)
    manual_adjustment_note = Column(String, default="")
    # How the opening AR balance is established: zero (default) | carry_forward | manual
    opening_mode = Column(String, default="zero")
    opening_source_session_id = Column(Integer)
    status = Column(String, default="draft")         # draft|processing|processed|error
    progress_stage = Column(String, default="")
    progress_pct = Column(Float, default=0.0)
    progress_rows_done = Column(Integer, default=0)
    progress_rows_total = Column(Integer, default=0)
    eta_seconds = Column(Integer, default=0)
    error = Column(Text, default="")
    created_at = Column(DateTime, default=_now)
    updated_at = Column(DateTime, default=_now, onupdate=_now)

    files = relationship("SessionFile", back_populates="session", cascade="all, delete-orphan")
    settlements = relationship("Settlement", back_populates="session", cascade="all, delete-orphan")
    exceptions = relationship("Exception_", back_populates="session", cascade="all, delete-orphan")
    fx_rates = relationship("FxRate", back_populates="session", cascade="all, delete-orphan")
    reserves = relationship("Reserve", back_populates="session", cascade="all, delete-orphan")


class SessionFile(Base):
    __tablename__ = "session_files"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    filename = Column(String)
    stored_path = Column(String)
    size_bytes = Column(Integer)
    sha256 = Column(String)
    worksheets = Column(Text)                        # JSON list
    data_sheet = Column(String)
    imported_rows = Column(Integer, default=0)
    min_date = Column(Date)
    max_date = Column(Date)
    currency = Column(String)
    marketplace = Column(String)
    status = Column(String, default="uploaded")      # uploaded|parsed|invalid
    message = Column(Text, default="")
    session = relationship("Session", back_populates="files")


class Settlement(Base):
    __tablename__ = "settlements"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    account_type = Column(String)
    settlement_id = Column(String)
    order_total = Column(Float, default=0.0)
    transfer_total = Column(Float, default=0.0)
    transfer_amount = Column(Float)                  # boundary/received transfer amount if any
    transfer_date = Column(Date)
    transfer_received = Column(Boolean)
    row_count = Column(Integer, default=0)
    first_date = Column(Date)
    last_date = Column(Date)
    status = Column(String)                          # paid|receivable
    session = relationship("Session", back_populates="settlements")


Index("ix_settlement_session", Settlement.session_id, Settlement.marketplace, Settlement.account_type)


class Transaction(Base):
    __tablename__ = "transactions"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    source_file = Column(String)
    source_sheet = Column(String)
    source_row = Column(Integer)
    marketplace = Column(String)
    settlement_id = Column(String)
    order_id = Column(String)
    sku = Column(String)
    txn_type = Column(String)                        # original (possibly localized) type
    txn_type_en = Column(String)                     # canonical English type
    account_type = Column(String)
    posted_date = Column(Date)
    total = Column(Float, default=0.0)
    currency = Column(String, default="USD")
    settlement_status = Column(String)               # paid|receivable
    receivable_flag = Column(Boolean, default=False)
    storage_flag = Column(Boolean, default=False)    # storage-fee detection drill-down


Index("ix_txn_session", Transaction.session_id)


class MappingRule(Base):
    """Admin-defined header alias: normalized source header -> canonical field.
    Lets Finance map new/renamed Amazon headers without code changes."""
    __tablename__ = "mapping_rules"
    id = Column(Integer, primary_key=True)
    normalized_header = Column(String, unique=True, nullable=False)
    field = Column(String, nullable=False)
    created_at = Column(DateTime, default=_now)
Index("ix_txn_settlement", Transaction.session_id, Transaction.settlement_id)
Index("ix_txn_type", Transaction.session_id, Transaction.txn_type)
Index("ix_txn_recv", Transaction.session_id, Transaction.receivable_flag)


class Exception_(Base):
    __tablename__ = "exceptions"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    category = Column(String)
    severity = Column(String)                        # error|warning|info
    detail = Column(Text)
    source = Column(String, default="")
    session = relationship("Session", back_populates="exceptions")


class FxRate(Base):
    __tablename__ = "fx_rates"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    currency = Column(String, default="USD")
    rate = Column(Float, default=1.0)
    source = Column(String, default="manual")
    rate_date = Column(Date)
    session = relationship("Session", back_populates="fx_rates")


class Reserve(Base):
    __tablename__ = "reserves"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    account_type = Column(String)
    amount = Column(Float, default=0.0)
    session = relationship("Session", back_populates="reserves")


class ReceivableResultRow(Base):
    __tablename__ = "receivable_results"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    account_type = Column(String)                    # or "TOTAL"
    additional_sales = Column(Float, default=0.0)
    reserve = Column(Float, default=0.0)
    receivable_local = Column(Float, default=0.0)
    fx_rate = Column(Float, default=1.0)
    receivable_usd = Column(Float, default=0.0)
    currency = Column(String, default="USD")


class ReconciliationRow(Base):
    __tablename__ = "reconciliation"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False, unique=True)
    uploaded_total = Column(Float)
    receivable_orders = Column(Float)
    paid_orders = Column(Float)
    transfers_total = Column(Float)
    reserve_total = Column(Float)
    manual_adjustments = Column(Float)
    final_receivable_usd = Column(Float)
    identity_difference = Column(Float)
    status = Column(String)
    notes = Column(Text, default="")
    # AR roll-forward components
    received_payouts = Column(Float, default=0.0)   # Σ transfers received (negative)
    all_payouts = Column(Float, default=0.0)         # Σ all transfers (negative)


class FxRateDaily(Base):
    """Optional per-date FX override. Falls back to the marketplace's month rate."""
    __tablename__ = "fx_rates_daily"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    rate_date = Column(Date)
    rate = Column(Float, default=1.0)
    source = Column(String, default="manual")


Index("ix_fx_daily", FxRateDaily.session_id, FxRateDaily.marketplace, FxRateDaily.rate_date)


class MarketPayout(Base):
    """Per-marketplace disbursement totals for the AR roll-forward.

    Transfers are attributed to the OWNER of their tagged settlement, not the file they
    appear in — Amazon repeats account-level payouts across country reports (e.g. the
    Belgium chain's transfers sit inside the Germany file).
    """
    __tablename__ = "market_payouts"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    received_payouts = Column(Float, default=0.0)    # negative
    all_payouts = Column(Float, default=0.0)         # negative


Index("ix_market_payout_session", MarketPayout.session_id, MarketPayout.marketplace)


class OpeningBalance(Base):
    __tablename__ = "opening_balances"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    marketplace = Column(String)
    amount = Column(Float, default=0.0)
    reason = Column(String, default="")
    source = Column(String, default="manual")        # manual | carried_forward
    updated_at = Column(DateTime, default=_now, onupdate=_now)


Index("ix_opening_session", OpeningBalance.session_id, OpeningBalance.marketplace)


class FinanceControl(Base):
    """Finance's manual control-sheet amounts + sign-off, for the reconciliation section."""
    __tablename__ = "finance_control"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False, unique=True)
    gross_sales = Column(Float)
    refunds = Column(Float)
    net_revenue = Column(Float)
    disbursements = Column(Float)
    closing_receivable = Column(Float)
    tolerance = Column(Float, default=1.0)
    verified_by = Column(String, default="")
    verified_at = Column(DateTime)
    comment = Column(Text, default="")


class JournalEntry(Base):
    __tablename__ = "journal_entries"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False, unique=True)
    entry_no = Column(String, default="")
    data = Column(Text, default="")     # JSON: periods + lines + receivable


class ExportRecord(Base):
    __tablename__ = "exports"
    id = Column(Integer, primary_key=True)
    session_id = Column(Integer, ForeignKey("sessions.id"), nullable=False)
    kind = Column(String, default="full")     # full | summary
    path = Column(String)
    sha256 = Column(String)
    size_bytes = Column(Integer)
    generated_at = Column(DateTime, default=_now)