"""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 app.utils.time import utcnow
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=utcnow, nullable=False)
    updated_at = db.Column(db.DateTime, default=utcnow,
                           onupdate=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 > 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=utcnow, nullable=False)

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

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