"""FormData + SheetImportRun — spreadsheet mirror and background import runs."""

from __future__ import annotations

import uuid
from datetime import datetime, timezone

from sqlalchemy import Column, DateTime, Index, delete, func, insert, or_
from sqlalchemy.dialects.postgresql import JSONB
from sqlalchemy.ext.asyncio import AsyncSession
from sqlmodel import Field, SQLModel, select


def _now() -> datetime:
    return datetime.now(timezone.utc)


_BULK_CHUNK = 1000


class FormData(SQLModel, table=True):
    """One spreadsheet data row. raw_record keeps the full original header→value map."""

    __tablename__ = "form_data"
    __table_args__ = (
        Index("ix_form_data_sheet_row_number", "sheet", "row_number", unique=True),
    )

    id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
    sheet: str = Field(nullable=False, index=True)
    # Optional link to a job post. DB FK only — no ORM Relationship (avoids
    # pulling job_posts into the sheet worker metadata graph).
    job_post_id: uuid.UUID | None = Field(default=None, index=True)
    row_number: int | None = Field(default=None)
    serial_no: str | None = Field(default=None)
    entry_year: str | None = Field(default=None)
    entry_month: str | None = Field(default=None)
    entry_date: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    entry_time: str | None = Field(default=None)
    screened_by: str | None = Field(default=None, index=True)
    name: str | None = Field(default=None, index=True)
    hr_comments: str | None = Field(default=None)
    candidate_number: str | None = Field(default=None)
    candidate_email: str | None = Field(default=None, index=True)
    profile_link: str | None = Field(default=None)
    area_of_expertise: str | None = Field(default=None)
    requisition_number: str | None = Field(default=None, index=True)
    position_suitable_for: str | None = Field(default=None)
    source_of_application: str | None = Field(default=None)
    age: int | None = Field(default=None)
    age_raw: str | None = Field(default=None)
    marital_status: str | None = Field(default=None)
    degree: str | None = Field(default=None)
    university: str | None = Field(default=None)
    experience: str | None = Field(default=None)
    experience_details: str | None = Field(default=None)
    area_of_residence: str | None = Field(default=None)
    communication_skills: int | None = Field(default=None)
    preferred_timings: str | None = Field(default=None)
    ho_availability: str | None = Field(default=None)
    current_company: str | None = Field(default=None)
    reason_for_leaving: str | None = Field(default=None)
    notice_period: str | None = Field(default=None)
    current_salary: str | None = Field(default=None)
    current_salary_value: int | None = Field(default=None)
    expected_salary: str | None = Field(default=None)
    expected_salary_value: int | None = Field(default=None)
    pros: str | None = Field(default=None)
    cons: str | None = Field(default=None)

    raw_record: dict | None = Field(default=None, sa_column=Column(JSONB))
    imported_at: datetime = Field(default_factory=_now, sa_type=DateTime(timezone=True))
    created_at: datetime = Field(default_factory=_now, sa_type=DateTime(timezone=True))
    updated_at: datetime = Field(default_factory=_now, sa_type=DateTime(timezone=True))

    @classmethod
    def _filters(cls, *, sheet=None, search=None):
        filters = []
        if sheet:
            filters.append(cls.sheet == sheet)
        if search:
            # Twelve unanchored ILIKEs over ~26k rows is a sequential scan of a few
            # tens of ms — acceptable at this size; a pg_trgm GIN index is the
            # upgrade if the sheet grows an order of magnitude.
            pattern = f"%{search}%"
            filters.append(or_(
                cls.name.ilike(pattern),
                cls.candidate_email.ilike(pattern),
                cls.candidate_number.ilike(pattern),
                cls.screened_by.ilike(pattern),
                cls.degree.ilike(pattern),
                cls.university.ilike(pattern),
                cls.experience.ilike(pattern),
                cls.experience_details.ilike(pattern),
                cls.current_company.ilike(pattern),
                cls.position_suitable_for.ilike(pattern),
                cls.area_of_expertise.ilike(pattern),
                cls.source_of_application.ilike(pattern),
            ))
        return filters

    @classmethod
    async def get_form_data_by_id(cls, session: AsyncSession, record_id):
        try:
            rid = uuid.UUID(str(record_id))
        except (TypeError, ValueError):
            return None
        result = await session.execute(select(cls).where(cls.id == rid))
        return result.scalars().first()

    @classmethod
    async def fetch_form_data(cls, session: AsyncSession, *, sheet=None, search=None, top=None, skip=None):
        statement = select(cls).order_by(cls.sheet, cls.row_number)
        for clause in cls._filters(sheet=sheet, search=search):
            statement = statement.where(clause)
        if skip:
            statement = statement.offset(skip)
        if top is not None:
            statement = statement.limit(top)
        result = await session.execute(statement)
        return result.scalars().all()

    @classmethod
    async def count_form_data(cls, session: AsyncSession, *, sheet=None, search=None):
        statement = select(func.count()).select_from(cls)
        for clause in cls._filters(sheet=sheet, search=search):
            statement = statement.where(clause)
        result = await session.execute(statement)
        return result.scalar_one()

    @classmethod
    async def get_sheet_names(cls, session: AsyncSession):
        result = await session.execute(
            select(cls.sheet).distinct().order_by(cls.sheet)
        )
        return list(result.scalars().all())

    @classmethod
    async def delete_by_sheet(cls, session: AsyncSession, sheet: str, *, commit: bool = True):
        count_result = await session.execute(
            select(func.count()).select_from(cls).where(cls.sheet == sheet)
        )
        deleted = count_result.scalar_one()
        await session.execute(delete(cls).where(cls.sheet == sheet))
        if commit:
            await session.commit()
        return deleted

    @classmethod
    async def insert_form_data_bulk(
        cls, session: AsyncSession, records: list[dict], *, commit: bool = True,
    ):
        # Core insertmanyvalues — building ~26k ORM instances is the slow path.
        # default_factory does not run on Core insert, so stamp timestamps here.
        now = _now()
        total = 0
        for start in range(0, len(records), _BULK_CHUNK):
            chunk = []
            for fields in records[start:start + _BULK_CHUNK]:
                row = dict(fields)
                row.setdefault("id", uuid.uuid4())
                row.setdefault("imported_at", now)
                row.setdefault("created_at", now)
                row.setdefault("updated_at", now)
                chunk.append(row)
            if chunk:
                await session.execute(insert(cls), chunk)
                total += len(chunk)
        if commit:
            await session.commit()
        return total

    @classmethod
    async def replace_sheet(cls, session: AsyncSession, sheet: str, records: list[dict]):
        """Delete + insert in one transaction so a mid-insert failure keeps prior rows."""
        deleted = await cls.delete_by_sheet(session, sheet, commit=False)
        inserted = await cls.insert_form_data_bulk(session, records, commit=False)
        await session.commit()
        return {"deleted": deleted, "inserted": inserted}


class SheetImportRun(SQLModel, table=True):
    """One Google Sheet → FormData import job (Taskiq). Survives tab close."""

    __tablename__ = "sheet_import_runs"

    id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
    status: str = Field(default="queued", index=True)  # queued|running|completed|failed
    task_id: str | None = Field(default=None)
    # Plain UUID — no ORM FK. Importing users.models pulls Users→Inbox relationships
    # that the sheet worker does not load; the DB constraint still enforces integrity.
    created_by: uuid.UUID | None = Field(default=None)
    tab: str | None = Field(default=None)  # None = import all tabs
    report: dict | None = Field(default=None, sa_column=Column(JSONB))
    error: str | None = Field(default=None)
    created_at: datetime = Field(default_factory=_now, sa_type=DateTime(timezone=True))
    started_at: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    finished_at: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))

    @staticmethod
    def _as_uuid(record_id) -> uuid.UUID | None:
        if record_id in (None, ""):
            return None
        try:
            return uuid.UUID(str(record_id))
        except ValueError:
            return None

    @classmethod
    async def get_by_id(cls, session: AsyncSession, record_id):
        uid = cls._as_uuid(record_id)
        if uid is None:
            return None
        result = await session.execute(select(cls).where(cls.id == uid))
        return result.scalars().first()

    @classmethod
    async def get_active(cls, session: AsyncSession):
        result = await session.execute(
            select(cls)
            .where(cls.status.in_(("queued", "running")))
            .order_by(cls.created_at.desc())
        )
        return result.scalars().first()

    @classmethod
    async def insert_run(cls, session: AsyncSession, fields: dict, *, commit: bool = True):
        row = cls(**fields)
        session.add(row)
        if commit:
            await session.commit()
            await session.refresh(row)
        return row

    @classmethod
    async def update_run(cls, session: AsyncSession, record_id, fields: dict, *, commit: bool = True):
        row = await cls.get_by_id(session, record_id)
        if not row:
            return None
        for key, value in fields.items():
            setattr(row, key, value)
        session.add(row)
        if commit:
            await session.commit()
            await session.refresh(row)
        return row