"""Ad and Sponsor models.

Ad: internal ad server. Slots: header, sidebar, inline, footer.
Targeting: lang (nullable = all), geo_state (nullable = all).
Impression/click counters on the model; Redis batching added in Phase 7.

Sponsor: paid directory listing + optional category sponsorship.
Category sponsor FK wired to categories.sponsor_id (set separately).

PromotedKeyword: pinned listing for a search keyword (promoted search).
"""
from datetime import datetime
from app.utils.time import utcnow
from app.extensions import db


class Ad(db.Model):
    __tablename__ = "ads"

    SLOTS = ["header", "sidebar", "inline", "footer"]

    id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                   primary_key=True, autoincrement=True)
    advertiser_name = db.Column(db.String(120), nullable=False)
    slot = db.Column(db.Enum("header", "sidebar", "inline", "footer",
                             name="ad_slot"), nullable=False)
    creative_path = db.Column(db.String(255), nullable=True)   # image file rel path
    target_url = db.Column(db.String(512), nullable=False)
    alt_text = db.Column(db.String(200), nullable=True)

    # targeting (null = match all)
    lang = db.Column(db.String(5), nullable=True)
    geo_state = db.Column(db.String(2), nullable=True)

    starts_at = db.Column(db.DateTime, nullable=False, index=True)
    ends_at = db.Column(db.DateTime, nullable=False, index=True)
    impressions = db.Column(db.Integer, nullable=False, default=0)
    clicks = db.Column(db.Integer, nullable=False, default=0)
    is_active = db.Column(db.Boolean, nullable=False, default=True)

    created_at = db.Column(db.DateTime, default=utcnow, nullable=False)
    updated_at = db.Column(db.DateTime, default=utcnow,
                           onupdate=utcnow, nullable=False)

    @property
    def ctr(self):
        if not self.impressions:
            return 0.0
        return round(self.clicks / self.impressions * 100, 2)

    @property
    def is_running(self):
        now = utcnow()
        return self.is_active and self.starts_at <= now <= self.ends_at

    def __repr__(self):
        return f"<Ad {self.id} slot={self.slot} adv={self.advertiser_name[:20]}>"


class Sponsor(db.Model):
    __tablename__ = "sponsors"

    TIERS = ["directory", "category"]

    id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                   primary_key=True, autoincrement=True)
    name = db.Column(db.String(120), nullable=False)
    logo_path = db.Column(db.String(255), nullable=True)
    url = db.Column(db.String(512), nullable=False)
    tagline = db.Column(db.String(160), nullable=True)
    tier = db.Column(db.Enum("directory", "category", name="sponsor_tier"),
                     nullable=False, default="directory")
    category_id = db.Column(
        db.BigInteger().with_variant(db.Integer, "sqlite"),
        db.ForeignKey("categories.id"), nullable=True)
    starts_at = db.Column(db.DateTime, nullable=False)
    ends_at = db.Column(db.DateTime, nullable=False)
    is_active = db.Column(db.Boolean, nullable=False, default=True)
    created_at = db.Column(db.DateTime, default=utcnow, nullable=False)

    category = db.relationship("Category",
                               backref=db.backref("sponsors", lazy="selectin"))

    @property
    def is_running(self):
        now = utcnow()
        return self.is_active and self.starts_at <= now <= self.ends_at

    def __repr__(self):
        return f"<Sponsor {self.name} tier={self.tier}>"


class PromotedKeyword(db.Model):
    """A listing pinned to the top of search results for a given keyword."""
    __tablename__ = "promoted_keywords"
    __table_args__ = (
        db.UniqueConstraint("keyword", "listing_id", name="uq_pk_kw_listing"),
    )

    id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                   primary_key=True, autoincrement=True)
    keyword = db.Column(db.String(80), nullable=False, index=True)
    listing_id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                           db.ForeignKey("listings.id"), nullable=False)
    priority = db.Column(db.Integer, nullable=False, default=0)
    expires_at = db.Column(db.DateTime, nullable=False, index=True)
    created_at = db.Column(db.DateTime, default=utcnow, nullable=False)

    listing = db.relationship("Listing",
                              backref=db.backref("promoted_keywords",
                                                 lazy="selectin"))

    @property
    def is_active(self):
        return self.expires_at > utcnow()

    def __repr__(self):
        return f"<PromotedKeyword '{self.keyword}' L{self.listing_id}>"