from sqlalchemy import Boolean, Column, Date, DateTime, ForeignKey, Integer, String, Table, UniqueConstraint
from sqlalchemy.sql import func
from app.extensions import db


# ── Many-to-many: references ↔ musicians ─────────────────────
reference_musicians = Table(
    "reference_musicians",
    db.metadata,
    Column("reference_id", Integer, ForeignKey("references.id", ondelete="CASCADE"), primary_key=True),
    Column("musician_id",  Integer, ForeignKey("musicians.id",  ondelete="CASCADE"), primary_key=True),
)


class Musician(db.Model):
    __tablename__ = "musicians"

    id   = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String, nullable=False, unique=True)

    references        = db.relationship("Reference",       secondary=reference_musicians, back_populates="musicians")
    instrument_entries = db.relationship("TuneByInstrument", back_populates="learned_from_musician")

    def to_dict(self):
        return {"id": self.id, "name": self.name}


class Source(db.Model):
    __tablename__ = "sources"

    id   = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String, nullable=False, unique=True)

    tunes = db.relationship("Tune", back_populates="source")

    def to_dict(self):
        return {"id": self.id, "name": self.name}


class Instrument(db.Model):
    __tablename__ = "instruments"

    id   = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String, nullable=False, unique=True)

    entries = db.relationship("TuneByInstrument", back_populates="instrument")

    def to_dict(self):
        return {"id": self.id, "name": self.name}


class Tuning(db.Model):
    __tablename__ = "tunings"

    id   = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String, nullable=False, unique=True)

    entries = db.relationship("TuneByInstrument", back_populates="tuning")

    def to_dict(self):
        return {"id": self.id, "name": self.name}


class Tune(db.Model):
    __tablename__ = "tunes"

    id        = Column(Integer, primary_key=True, autoincrement=True)
    name      = Column(String,  nullable=True)
    key       = Column(String,  nullable=True)
    modal     = Column(Boolean, nullable=True)
    source_id  = Column(Integer, ForeignKey("sources.id", ondelete="SET NULL"), nullable=True)
    created_at = Column(DateTime(timezone=True), server_default=func.now(), nullable=True)

    source      = db.relationship("Source",          back_populates="tunes")
    instruments = db.relationship("TuneByInstrument", back_populates="tune", cascade="all, delete-orphan")
    notes       = db.relationship("TuneNote",         back_populates="tune", cascade="all, delete-orphan")
    references  = db.relationship("Reference",        back_populates="tune", cascade="all, delete-orphan")

    def to_dict(self):
        return {
            "id":          self.id,
            "name":        self.name,
            "key":         self.key,
            "modal":       self.modal,
            "source_id":   self.source_id,
            "created_at":  self.created_at.isoformat() if self.created_at else None,
            "source":      self.source.to_dict() if self.source else None,
            "instruments": [i.to_dict() for i in self.instruments],
            "notes":       [n.to_dict() for n in self.notes],
            "references":  [r.to_dict() for r in self.references],
        }


class TuneByInstrument(db.Model):
    __tablename__ = "tune_by_instrument"
    __table_args__ = (UniqueConstraint("tune_id", "instrument_id", name="uq_tune_instrument"),)

    id              = Column(Integer, primary_key=True, autoincrement=True)
    tune_id         = Column(Integer, ForeignKey("tunes.id",       ondelete="CASCADE"),  nullable=False)
    instrument_id   = Column(Integer, ForeignKey("instruments.id", ondelete="CASCADE"),  nullable=False)
    learned_from_id = Column(Integer, ForeignKey("musicians.id",   ondelete="SET NULL"), nullable=True)
    tuning_id       = Column(Integer, ForeignKey("tunings.id",     ondelete="SET NULL"), nullable=True)
    date_learned    = Column(Date,    nullable=True)
    callable        = Column(Boolean, nullable=True)
    review          = Column(Boolean, nullable=True)
    to_learn        = Column(Boolean, nullable=True, default=False)
    difficulty      = Column(String,  nullable=True)

    tune                  = db.relationship("Tune",       back_populates="instruments")
    instrument            = db.relationship("Instrument", back_populates="entries")
    tuning                = db.relationship("Tuning",     back_populates="entries")
    learned_from_musician = db.relationship("Musician",   back_populates="instrument_entries")
    notes                 = db.relationship("TuneByInstrumentNote", back_populates="entry", cascade="all, delete-orphan")

    def to_dict(self):
        return {
            "id":              self.id,
            "tune_id":         self.tune_id,
            "instrument_id":   self.instrument_id,
            "instrument_name": self.instrument.name if self.instrument else None,
            "learned_from_id": self.learned_from_id,
            "learned_from":    self.learned_from_musician.name if self.learned_from_musician else None,
            "date_learned":    self.date_learned.isoformat() if self.date_learned else None,
            "tuning_id":       self.tuning_id,
            "tuning":          self.tuning.name if self.tuning else None,
            "callable":        self.callable,
            "review":          self.review,
            "to_learn":        self.to_learn,
            "difficulty":      self.difficulty,
            "notes":           [n.to_dict() for n in self.notes],
        }


class TuneNote(db.Model):
    __tablename__ = "tune_notes"

    id      = Column(Integer, primary_key=True, autoincrement=True)
    tune_id = Column(Integer, ForeignKey("tunes.id", ondelete="CASCADE"), nullable=False)
    note    = Column(String, nullable=True)

    tune = db.relationship("Tune", back_populates="notes")

    def to_dict(self):
        return {"id": self.id, "tune_id": self.tune_id, "note": self.note}


class TuneByInstrumentNote(db.Model):
    __tablename__ = "tune_by_instrument_notes"

    id                    = Column(Integer, primary_key=True, autoincrement=True)
    tune_by_instrument_id = Column(Integer, ForeignKey("tune_by_instrument.id", ondelete="CASCADE"), nullable=False)
    note                  = Column(String, nullable=True)

    entry = db.relationship("TuneByInstrument", back_populates="notes")

    def to_dict(self):
        return {"id": self.id, "tune_by_instrument_id": self.tune_by_instrument_id, "note": self.note}


class ReferenceSite(db.Model):
    __tablename__ = "reference_sites"

    id   = Column(Integer, primary_key=True, autoincrement=True)
    name = Column(String, nullable=False, unique=True)

    references = db.relationship("Reference", back_populates="site")

    def to_dict(self):
        return {"id": self.id, "name": self.name}


class Reference(db.Model):
    __tablename__ = "references"

    id      = Column(Integer, primary_key=True, autoincrement=True)
    tune_id = Column(Integer, ForeignKey("tunes.id", ondelete="CASCADE"), nullable=True)
    link    = Column(String, nullable=True)
    site_id = Column(Integer, ForeignKey("reference_sites.id", ondelete="SET NULL"), nullable=True)

    tune      = db.relationship("Tune",          back_populates="references")
    site      = db.relationship("ReferenceSite", back_populates="references")
    musicians = db.relationship("Musician",      secondary=reference_musicians, back_populates="references")

    def to_dict(self):
        return {
            "id":        self.id,
            "tune_id":   self.tune_id,
            "link":      self.link,
            "site_id":   self.site_id,
            "site":      self.site.to_dict() if self.site else None,
            "musicians": [m.to_dict() for m in self.musicians],
        }