"""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, case, 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)
    # Set when this form row is promoted into the hiring pipeline (Users +
    # manual_upload_candidate). Idempotency key for assign / shortlist.
    manual_upload_candidate_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)
    gender: str | None = Field(default=None)
    date_of_birth: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    cnic: str | None = Field(default=None, index=True)
    cgpa: str | None = Field(default=None)
    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)
    resume_link: str | None = Field(default=None)
    # Drive CV extract JSON written by @extract_drive_cvs after sheet ingest.
    extracted_data: dict | None = Field(default=None, sa_column=Column(JSONB))
    area_of_expertise: str | None = Field(default=None)
    requisition_number: str | None = Field(default=None, index=True)
    position_applied_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)
    university_other: 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)
    residing_city: str | None = Field(default=None)
    residing_country: 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)
    director_poc_category: str | None = Field(default=None)
    pros: str | None = Field(default=None)
    cons: str | None = Field(default=None)

    # Same allowlist as inbox_messages.processing_state: unread|imported|processed|rejected.
    # server_default is load-bearing — ALTER on a populated form_data table.
    processing_state: str = Field(default="unread", sa_column_kwargs={"server_default": "unread"})
    is_duplicate: bool = Field(default=False, sa_column_kwargs={"server_default": "false"})

    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, processing_state=None, is_duplicate=None):
        filters = []
        if sheet:
            filters.append(cls.sheet == sheet)
        if processing_state:
            filters.append(cls.processing_state == processing_state)
        if is_duplicate is not None:
            filters.append(cls.is_duplicate == bool(is_duplicate))
        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_applied_for.ilike(pattern),
                cls.area_of_expertise.ilike(pattern),
                cls.source_of_application.ilike(pattern),
                cls.cnic.ilike(pattern),
                cls.residing_city.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 set_job_post(cls, session: AsyncSession, record_id, job_post_id):
        """Set or clear job_post_id; returns the row or None if missing."""
        row = await cls.get_form_data_by_id(session, record_id)
        if not row:
            return None
        if job_post_id is None:
            row.job_post_id = None
        else:
            try:
                row.job_post_id = uuid.UUID(str(job_post_id))
            except (TypeError, ValueError):
                return None
        row.updated_at = _now()
        session.add(row)
        await session.commit()
        await session.refresh(row)
        return row

    @classmethod
    async def set_processing_state(cls, session: AsyncSession, record_id, processing_state: str):
        row = await cls.get_form_data_by_id(session, record_id)
        if not row:
            return None
        row.processing_state = processing_state
        row.updated_at = _now()
        session.add(row)
        await session.commit()
        await session.refresh(row)
        return row

    @classmethod
    async def set_duplicate(cls, session: AsyncSession, record_id, is_duplicate: bool):
        row = await cls.get_form_data_by_id(session, record_id)
        if not row:
            return None
        row.is_duplicate = bool(is_duplicate)
        row.updated_at = _now()
        session.add(row)
        await session.commit()
        await session.refresh(row)
        return row

    @classmethod
    async def link_manual_upload(cls, session: AsyncSession, record_id, manual_upload_candidate_id, *, commit: bool = True):
        row = await cls.get_form_data_by_id(session, record_id)
        if not row:
            return None
        try:
            row.manual_upload_candidate_id = uuid.UUID(str(manual_upload_candidate_id))
        except (TypeError, ValueError):
            return None
        row.updated_at = _now()
        session.add(row)
        if commit:
            await session.commit()
            await session.refresh(row)
        return row

    @classmethod
    async def set_extracted_data(
        cls, session: AsyncSession, record_id, extracted_data, *, commit: bool = True,
    ):
        row = await cls.get_form_data_by_id(session, record_id)
        if not row:
            return None
        row.extracted_data = extracted_data
        row.updated_at = _now()
        session.add(row)
        if commit:
            await session.commit()
            await session.refresh(row)
        return row

    @classmethod
    async def fetch_resume_links(cls, session: AsyncSession, sheet: str):
        """(id, resume_link) for one tab. Blank links are dropped."""
        statement = (
            select(cls.id, cls.resume_link)
            .where(cls.sheet == sheet)
            .where(cls.resume_link.is_not(None))
            .order_by(cls.row_number)
        )
        result = await session.execute(statement)
        rows = []
        for record_id, link in result.all():
            text = (link or "").strip()
            if text:
                rows.append((record_id, text))
        return rows

    @classmethod
    async def fetch_form_data(
        cls, session: AsyncSession, *, sheet=None, search=None,
        processing_state=None, is_duplicate=None, offset=0, limit=None,
    ):
        statement = select(cls).order_by(cls.sheet, cls.row_number)
        for clause in cls._filters(
            sheet=sheet, search=search,
            processing_state=processing_state, is_duplicate=is_duplicate,
        ):
            statement = statement.where(clause)
        if offset:
            statement = statement.offset(offset)
        if limit is not None:
            statement = statement.limit(limit)
        statement = statement.order_by(cls.row_number)
        result = await session.execute(statement)
        return result.scalars().all()

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

    @classmethod
    async def count_processing(cls, session: AsyncSession, *, sheet=None):
        """Tab badge counts for the Sheet Forms channel."""
        statement = select(
            func.count().label("all"),
            func.coalesce(func.sum(case((cls.processing_state == "unread", 1), else_=0)), 0).label("unread"),
            func.coalesce(func.sum(case((cls.processing_state == "imported", 1), else_=0)), 0).label("imported"),
            func.coalesce(func.sum(case((cls.processing_state == "processed", 1), else_=0)), 0).label("processed"),
            func.coalesce(func.sum(case((cls.processing_state == "rejected", 1), else_=0)), 0).label("rejected"),
            func.coalesce(func.sum(case((cls.is_duplicate == True, 1), else_=0)), 0).label("duplicates"),  # noqa: E712
        ).select_from(cls)
        if sheet:
            statement = statement.where(cls.sheet == sheet)
        row = (await session.execute(statement)).one()
        return {
            "all": int(row.all or 0),
            "unread": int(row.unread or 0),
            "imported": int(row.imported or 0),
            "processed": int(row.processed or 0),
            "rejected": int(row.rejected or 0),
            "duplicates": int(row.duplicates or 0),
        }

    @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}

    @staticmethod
    def _cell(data: dict, key: str):
        """Sheet cell → stripped str, or None if missing/blank."""
        value = data.get(key)
        if value is None:
            return None
        text = str(value).strip()
        return text if text else None

    @classmethod
    def from_sheet_row(cls, sheet: str, row_number: int, data: dict) -> dict:
        """Build FormData kwargs from one sheet row dict (exact header keys, no aliases).

        Year of Graduation: prefer the second column when present; else the first;
        else None. Duplicate headers are renamed Year of Graduation_1 by normalise_headers.
        """
        from g_sheet.plugins import parse_date, parse_date_time, parse_salary

        first_year = cls._cell(data, "Year of Graduation")
        second_year = cls._cell(data, "Year of Graduation_1")
        if second_year:
            entry_year = second_year
        elif first_year:
            entry_year = first_year
        else:
            entry_year = None

        timestamp_raw = data.get("Timestamp")
        entry_date, entry_time = parse_date_time(timestamp_raw)

        current_salary = cls._cell(data, "Current Salary")
        expected_salary = cls._cell(data, "Expected Salary")

        return {
            "sheet": sheet,
            "row_number": row_number,
            "raw_record": dict(data),
            "entry_year": entry_year,
            "entry_date": entry_date,
            "entry_time": entry_time,
            "name": cls._cell(data, "Full Name"),
            "gender": cls._cell(data, "Gender"),
            "candidate_number": cls._cell(data, "Phone number (03XX-XXXXXXX)"),
            "candidate_email": cls._cell(data, "Email"),
            "date_of_birth": parse_date(data.get("Date of Birth")),
            "cnic": cls._cell(data, "National Identification No. (42000-XXXXXXX-X)"),
            "marital_status": cls._cell(data, "Marital Status"),
            "position_applied_for": cls._cell(data, "Position Applied For"),
            "profile_link": cls._cell(data, "LinkedIn Profile Link"),
            "residing_country": cls._cell(data, "Residing Country"),
            "residing_city": cls._cell(data, "Residing City"),
            "ho_availability": cls._cell(data, "Are you willing to relocate?"),
            "degree": cls._cell(data, "Educational Degree"),
            "university": cls._cell(data, "University"),
            "university_other": cls._cell(
                data,
                "If your university is not listed above, please specify its name.",
            ),
            "notice_period": cls._cell(data, "How soon can you join us?"),
            "resume_link": cls._cell(data, "Drop your updated resume"),
            "source_of_application": cls._cell(
                data,
                "Where did you hear about the position you're applying for?",
            ),
            "cgpa": cls._cell(data, "CGPA"),
            "area_of_expertise": cls._cell(data, "Area of Interest"),
            "current_salary": current_salary,
            "current_salary_value": parse_salary(current_salary),
            "expected_salary": expected_salary,
            "expected_salary_value": parse_salary(expected_salary),
            "screened_by": cls._cell(data, "Recruiter"),
            "hr_comments": cls._cell(data, "HR Comment"),
            "director_poc_category": cls._cell(data, "Director / POC / Category"),
        }


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 get_latest(cls, session: AsyncSession):
        result = await session.execute(
            select(cls).order_by(cls.created_at.desc()).limit(1)
        )
        return result.scalars().first()

    @classmethod
    async def delete_failed(cls, session: AsyncSession, *, commit: bool = True):
        """Drop failed import rows so a new job is not blocked by them."""
        result = await session.execute(delete(cls).where(cls.status == "failed"))
        if commit:
            await session.commit()
        return result.rowcount

    @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