"""Listing model.

Portability notes (see README "MySQL upgrades"):
- Location stored as lat/lng floats; radius search uses a bounding-box prefilter
  + haversine refine. On MySQL you may add a generated POINT + SPATIAL INDEX.
- Hot filter fields (condition/job_type/salary) are denormalized onto indexed
  columns, populated in the service layer from `attributes`. On MySQL these can
  instead be GENERATED ALWAYS columns over the JSON.
- Free-text search uses the accent-insensitive `title_norm` + body LIKE. On
  MySQL add a FULLTEXT(title, body) index and switch to MATCH ... AGAINST.
"""
from datetime import datetime
from sqlalchemy import JSON, Index
from app.extensions import db
from app.models.enums import ListingStatus, Lang


class Listing(db.Model):
    __tablename__ = "listings"

    id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                   primary_key=True, autoincrement=True)
    user_id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                        db.ForeignKey("users.id"), nullable=False, index=True)
    category_id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                            db.ForeignKey("categories.id"), nullable=False, index=True)

    title = db.Column(db.String(140), nullable=False)
    title_norm = db.Column(db.String(140), nullable=False, index=True)  # accent-stripped
    body = db.Column(db.Text, nullable=False)
    lang = db.Column(db.Enum(Lang), nullable=False, default=Lang.en)

    price_cents = db.Column(db.Integer, nullable=True, index=True)

    # location
    zip = db.Column(db.String(12), nullable=True, index=True)
    city = db.Column(db.String(80), nullable=True)
    state = db.Column(db.String(2), nullable=True, index=True)
    lat = db.Column(db.Float, nullable=True)
    lng = db.Column(db.Float, nullable=True)

    # category-specific values
    attributes = db.Column(JSON, nullable=False, default=dict)
    # denormalized hot filter columns (populated from attributes on save)
    attr_condition = db.Column(db.String(40), nullable=True, index=True)
    attr_job_type = db.Column(db.String(40), nullable=True, index=True)
    attr_salary_min = db.Column(db.Integer, nullable=True, index=True)
    attr_salary_max = db.Column(db.Integer, nullable=True, index=True)

    status = db.Column(db.Enum(ListingStatus), nullable=False,
                       default=ListingStatus.active, index=True)
    is_featured = db.Column(db.Boolean, nullable=False, default=False)
    bump_at = db.Column(db.DateTime, nullable=True)
    flag_count = db.Column(db.Integer, nullable=False, default=0)
    view_count = 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=datetime.utcnow, nullable=False)
    updated_at = db.Column(db.DateTime, default=datetime.utcnow,
                           onupdate=datetime.utcnow, nullable=False)

    user = db.relationship("User", backref=db.backref("listings", lazy="dynamic"))
    category = db.relationship("Category", back_populates="listings")
    images = db.relationship("ListingImage", back_populates="listing",
                             order_by="ListingImage.sort_order",
                             cascade="all, delete-orphan", lazy="selectin")

    __table_args__ = (
        Index("ix_listing_browse", "status", "expires_at"),
        Index("ix_listing_sort", "is_featured", "bump_at"),
    )

    @property
    def is_live(self):
        return (self.status == ListingStatus.active
                and self.expires_at > datetime.utcnow())

    @property
    def price_display(self):
        if self.price_cents is None:
            return None
        return f"${self.price_cents / 100:,.2f}"

    @property
    def cover(self):
        return self.images[0] if self.images else None

    def __repr__(self):
        return f"<Listing {self.id} {self.title[:24]!r}>"


class ListingImage(db.Model):
    __tablename__ = "listing_images"

    id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                   primary_key=True, autoincrement=True)
    listing_id = db.Column(db.BigInteger().with_variant(db.Integer, "sqlite"),
                           db.ForeignKey("listings.id"), nullable=False, index=True)
    path = db.Column(db.String(255), nullable=False)
    thumb_path = db.Column(db.String(255), nullable=True)
    sort_order = db.Column(db.Integer, nullable=False, default=0)
    width = db.Column(db.Integer, nullable=True)
    height = db.Column(db.Integer, nullable=True)
    created_at = db.Column(db.DateTime, default=datetime.utcnow, nullable=False)

    listing = db.relationship("Listing", back_populates="images")

    def __repr__(self):
        return f"<ListingImage {self.id} of L{self.listing_id}>"