import uuid
from datetime import datetime, timezone

from sqlalchemy import DateTime, func
from sqlalchemy.ext.asyncio import AsyncSession
from sqlmodel import Field, SQLModel, select


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


class Offers(SQLModel, table=True):
    __tablename__ = "offers"

    id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
    inbox_id: int | None = Field(default=None, index=True, foreign_key="inbox.id")
    manual_upload_candidate_id: uuid.UUID | None = Field(
        default=None, index=True, foreign_key="manual_upload_candidate.id",
    )
    form_data_id: uuid.UUID | None = Field(default=None, index=True, foreign_key="form_data.id")
    job_post_id: uuid.UUID = Field(foreign_key="job_posts.id")
    candidate_user_id: uuid.UUID = Field(foreign_key="users.id")
    status: str = Field(default="draft")
    base_salary: float = Field(default=0.0)
    currency: str = Field(default="USD")
    salary_period: str = Field(default="annual")
    signing_bonus: float | None = Field(default=None)
    annual_bonus_pct: float | None = Field(default=None)
    equity_units: int | None = Field(default=None)
    equity_instrument: str | None = Field(default=None)
    # Annexure J (offer email format) fields.
    cadre: str | None = Field(default=None)
    gross_salary_in_words: str | None = Field(default=None)
    subsidized_services: str | None = Field(default=None)
    probation_period: str | None = Field(default=None)
    notice_period: str | None = Field(default=None)
    work_location: str | None = Field(default=None)
    work_timings: str | None = Field(default=None)
    start_date: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    expiry_date: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    sent_at: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    responded_at: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    closed_at: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    issued_by: uuid.UUID | None = Field(default=None, foreign_key="users.id")
    created_by: uuid.UUID = Field(foreign_key="users.id")
    created_at: datetime = Field(default_factory=_now, sa_type=DateTime(timezone=True))
    updated_at: datetime = Field(default_factory=_now, 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_offer_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 fetch_offers(
        cls,
        session: AsyncSession,
        *,
        status: str | None = None,
        inbox_id: int | None = None,
        job_post_id=None,
        top: int | None = None,
        skip: int = 0,
    ):
        statement = select(cls)
        if status:
            statement = statement.where(cls.status == status)
        if inbox_id is not None:
            statement = statement.where(cls.inbox_id == int(inbox_id))
        jid = cls._as_uuid(job_post_id) if job_post_id is not None else None
        if jid is not None:
            statement = statement.where(cls.job_post_id == jid)
        count_statement = select(func.count()).select_from(statement.subquery())
        total = (await session.execute(count_statement)).scalar_one()
        statement = statement.order_by(cls.created_at.desc())
        if skip:
            statement = statement.offset(skip)
        if top is not None:
            statement = statement.limit(top)
        result = await session.execute(statement)
        return list(result.scalars().all()), total

    @classmethod
    async def insert_offer(cls, session: AsyncSession, fields: dict):
        row = cls(**fields)
        session.add(row)
        await session.commit()
        return await cls.get_offer_by_id(session, row.id)

    @classmethod
    async def update_offer(cls, session: AsyncSession, record_id, fields: dict):
        row = await cls.get_offer_by_id(session, record_id)
        if not row:
            return None
        for key, value in fields.items():
            setattr(row, key, value)
        row.updated_at = _now()
        session.add(row)
        await session.commit()
        await session.refresh(row)
        return row

    @classmethod
    async def count_by_status(cls, session: AsyncSession, status: str, *, from_date=None, to_date=None):
        statement = select(func.count()).select_from(cls).where(cls.status == status)
        if from_date is not None:
            statement = statement.where(cls.created_at >= from_date)
        if to_date is not None:
            statement = statement.where(cls.created_at < to_date)
        result = await session.execute(statement)
        return result.scalar_one()

    @classmethod
    def scoped_to_job(cls, statement, department=None, recruiter_id=None):
        if not department and not recruiter_id:
            return statement
        from job.job_post.models import JobPosts
        statement = statement.outerjoin(JobPosts, cls.job_post_id == JobPosts.id)
        if department:
            statement = statement.where(JobPosts.department == department)
        rid = cls._as_uuid(recruiter_id)
        if rid is not None:
            statement = statement.where(JobPosts.current_recruiter_id == rid)
        return statement

    @classmethod
    async def count_in_window(
        cls, session: AsyncSession, statuses=None, from_date=None, to_date=None,
        department=None, recruiter_id=None, *, exclude_draft=False,
    ):
        statement = select(func.count()).select_from(cls)
        if exclude_draft:
            statement = statement.where(cls.status != "draft")
        elif statuses:
            statement = statement.where(cls.status.in_(statuses))
        stamp = func.coalesce(cls.sent_at, cls.responded_at, cls.created_at)
        if from_date is not None:
            statement = statement.where(stamp >= from_date)
        if to_date is not None:
            statement = statement.where(stamp < to_date)
        statement = cls.scoped_to_job(statement, department, recruiter_id)
        result = await session.execute(statement)
        return int(result.scalar_one() or 0)

    @classmethod
    async def get_open_for_candidate_job(cls, session: AsyncSession, candidate_user_id, job_post_id):
        uid = cls._as_uuid(candidate_user_id)
        jid = cls._as_uuid(job_post_id)
        if uid is None or jid is None:
            return None
        result = await session.execute(
            select(cls)
            .where(cls.candidate_user_id == uid, cls.job_post_id == jid)
            .where(cls.status.in_(("sent", "negotiating")))
            .order_by(cls.created_at.desc())
        )
        return result.scalars().first()

    @classmethod
    async def get_failed_for_candidate_job(cls, session: AsyncSession, candidate_user_id, job_post_id):
        uid = cls._as_uuid(candidate_user_id)
        jid = cls._as_uuid(job_post_id)
        if uid is None or jid is None:
            return None
        result = await session.execute(
            select(cls)
            .where(cls.candidate_user_id == uid, cls.job_post_id == jid)
            .where(cls.status == "failed")
            .order_by(cls.created_at.desc())
        )
        return result.scalars().first()

    @classmethod
    async def get_draft_or_failed_for_candidate_job(cls, session: AsyncSession, candidate_user_id, job_post_id):
        uid = cls._as_uuid(candidate_user_id)
        jid = cls._as_uuid(job_post_id)
        if uid is None or jid is None:
            return None
        result = await session.execute(
            select(cls)
            .where(cls.candidate_user_id == uid, cls.job_post_id == jid)
            .where(cls.status.in_(("draft", "failed")))
            .order_by(cls.created_at.desc())
        )
        return result.scalars().first()


class OfferStatusHistory(SQLModel, table=True):
    __tablename__ = "offer_status_history"

    id: uuid.UUID = Field(default_factory=uuid.uuid4, primary_key=True)
    offer_id: uuid.UUID = Field(index=True, foreign_key="offers.id")
    from_status: str | None = Field(default=None)
    to_status: str
    valid_from: datetime = Field(default_factory=_now, sa_type=DateTime(timezone=True))
    valid_to: datetime | None = Field(default=None, sa_type=DateTime(timezone=True))
    changed_by: uuid.UUID | None = Field(default=None, foreign_key="users.id")
    actor_kind: str = Field(default="user")
    change_reason: str | None = Field(default=None)

    @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_offer(cls, session: AsyncSession, offer_id):
        uid = cls._as_uuid(offer_id)
        if uid is None:
            return []
        result = await session.execute(
            select(cls).where(cls.offer_id == uid).order_by(cls.valid_from.desc())
        )
        return list(result.scalars().all())

    @classmethod
    async def insert_history(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

import users.models as _users_models  # noqa: E402, F401
import job.candidate.models as _manual_models  # noqa: E402, F401
import g_sheet.models as _form_models  # noqa: E402, F401