from __future__ import annotations

from datetime import datetime, timezone

from sqlalchemy import Boolean, DateTime, Float, ForeignKey, Integer, String, Text, UniqueConstraint
from sqlalchemy.orm import Mapped, mapped_column

from app.core.db.common import CommonBase


class AccountingGSTR2BImportBatch(CommonBase):
    __tablename__ = "accounting_gstr2b_import_batches"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id", ondelete="CASCADE"), nullable=False, index=True)
    client_id: Mapped[int] = mapped_column(ForeignKey("clients.id", ondelete="CASCADE"), nullable=False, index=True)
    tally_guid: Mapped[str] = mapped_column(String(120), nullable=False, default="", index=True)

    original_filename: Mapped[str] = mapped_column(String(260), nullable=False, default="")
    file_sha256: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
    return_period: Mapped[str] = mapped_column(String(20), nullable=False, default="", index=True)
    source_kind: Mapped[str] = mapped_column(String(30), nullable=False, default="gstr2b_upload", index=True)

    status: Mapped[str] = mapped_column(String(30), nullable=False, default="imported", index=True)
    rows_read: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    rows_imported: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    rows_skipped_duplicate: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    rows_skipped_invalid: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    analyzed_rows: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    reviewed_rows: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    error_message: Mapped[str | None] = mapped_column(Text, nullable=True)

    imported_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    created_at_utc: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False, index=True
    )
    analyzed_at_utc: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    completed_at_utc: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)


class AccountingGSTR2BPurchase(CommonBase):
    __tablename__ = "accounting_gstr2b_purchases"
    __table_args__ = (
        UniqueConstraint(
            "tenant_id",
            "client_id",
            "supplier_gstin",
            "invoice_number",
            "invoice_date",
            "document_type",
            name="uq_accounting_gstr2b_purchase_document",
        ),
    )

    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
    tenant_id: Mapped[int] = mapped_column(ForeignKey("tenants.id", ondelete="CASCADE"), nullable=False, index=True)
    client_id: Mapped[int] = mapped_column(ForeignKey("clients.id", ondelete="CASCADE"), nullable=False, index=True)
    batch_id: Mapped[int] = mapped_column(
        ForeignKey("accounting_gstr2b_import_batches.id", ondelete="CASCADE"), nullable=False, index=True
    )
    tally_guid: Mapped[str] = mapped_column(String(120), nullable=False, default="", index=True)

    return_period: Mapped[str] = mapped_column(String(20), nullable=False, default="", index=True)
    supplier_gstin: Mapped[str] = mapped_column(String(20), nullable=False, default="", index=True)
    supplier_name: Mapped[str] = mapped_column(String(260), nullable=False, default="", index=True)

    invoice_number: Mapped[str] = mapped_column(String(160), nullable=False, default="", index=True)
    invoice_date: Mapped[str] = mapped_column(String(20), nullable=False, default="", index=True)
    document_type: Mapped[str] = mapped_column(String(40), nullable=False, default="invoice", index=True)
    invoice_type: Mapped[str] = mapped_column(String(80), nullable=False, default="")

    place_of_supply: Mapped[str] = mapped_column(String(120), nullable=False, default="")
    reverse_charge: Mapped[str] = mapped_column(String(20), nullable=False, default="")
    itc_availability: Mapped[str] = mapped_column(String(80), nullable=False, default="")

    taxable_value: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    igst: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    cgst: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    sgst: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    cess: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
    invoice_value: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)

    hsn_code: Mapped[str] = mapped_column(String(20), nullable=False, default="", index=True)
    description_text: Mapped[str | None] = mapped_column(Text, nullable=True)
    source_sheet: Mapped[str] = mapped_column(String(160), nullable=False, default="")
    source_row_number: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    source_row_hash: Mapped[str] = mapped_column(String(64), nullable=False, default="", index=True)

    review_status: Mapped[str] = mapped_column(String(30), nullable=False, default="pending_analysis", index=True)
    suggested_nature_id: Mapped[int | None] = mapped_column(
        ForeignKey("accounting_natures.id", ondelete="SET NULL"), nullable=True, index=True
    )
    suggested_ledger_name: Mapped[str] = mapped_column(String(240), nullable=False, default="")
    suggested_confidence: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
    suggestion_explanation_json: Mapped[str | None] = mapped_column(Text, nullable=True)

    final_nature_id: Mapped[int | None] = mapped_column(
        ForeignKey("accounting_natures.id", ondelete="SET NULL"), nullable=True, index=True
    )
    final_ledger_name: Mapped[str] = mapped_column(String(240), nullable=False, default="")
    reviewed_by_user_id: Mapped[int | None] = mapped_column(ForeignKey("users.id", ondelete="SET NULL"), nullable=True)
    reviewed_at_utc: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    posting_status: Mapped[str] = mapped_column(String(30), nullable=False, default="not_enabled", index=True)
    is_duplicate_source: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)

    created_at_utc: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), default=lambda: datetime.now(timezone.utc), nullable=False, index=True
    )
    updated_at_utc: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        default=lambda: datetime.now(timezone.utc),
        onupdate=lambda: datetime.now(timezone.utc),
        nullable=False,
    )