"""Custom fields: site-defined extra attributes per asset type.

A CustomField is a definition scoped to one asset type (machine, computer,
printer, network_device). A CustomFieldValue holds one asset's value for one
field. This is the generic form of the built-in identifier columns - sites add
their own attributes without a schema change.
"""

from shopdb.extensions import db

# Allowed datatypes for a custom field. Values are always stored as text and
# cast on render/input by the frontend.
CUSTOM_FIELD_DATATYPES = ('text', 'number', 'date', 'boolean', 'select')


class CustomField(db.Model):
    __tablename__ = 'customfields'

    fieldid = db.Column(db.Integer, primary_key=True)
    assettypeid = db.Column(
        db.Integer,
        db.ForeignKey('assettypes.assettypeid'),
        nullable=False,
        comment='Which asset category this field applies to'
    )
    # Machine-name key, unique per asset type. Used for stable references.
    fieldkey = db.Column(db.String(50), nullable=False)
    label = db.Column(db.String(150), nullable=False)
    datatype = db.Column(db.String(20), nullable=False, server_default='text')
    # JSON array of options, only meaningful when datatype='select'
    options = db.Column(db.Text)
    showondetail = db.Column(db.Boolean, nullable=False, server_default='1')
    showonform = db.Column(db.Boolean, nullable=False, server_default='1')
    sortorder = db.Column(db.Integer, nullable=False, server_default='0')
    isactive = db.Column(db.Boolean, nullable=False, server_default='1')
    # When true, this field's values are matched by global search.
    searchable = db.Column(db.Boolean, nullable=False, server_default='0')

    __table_args__ = (
        db.UniqueConstraint('assettypeid', 'fieldkey', name='uq_customfield_type_key'),
    )

    def to_dict(self):
        import json
        parsed_options = []
        if self.options:
            try:
                parsed_options = json.loads(self.options)
            except (ValueError, TypeError):
                parsed_options = []
        return {
            'fieldid': self.fieldid,
            'assettypeid': self.assettypeid,
            'fieldkey': self.fieldkey,
            'label': self.label,
            'datatype': self.datatype,
            'options': parsed_options,
            'showondetail': bool(self.showondetail),
            'showonform': bool(self.showonform),
            'sortorder': self.sortorder,
            'isactive': bool(self.isactive),
            'searchable': bool(self.searchable),
        }


class CustomFieldValue(db.Model):
    __tablename__ = 'customfieldvalues'

    valueid = db.Column(db.Integer, primary_key=True)
    fieldid = db.Column(
        db.Integer,
        db.ForeignKey('customfields.fieldid', ondelete='CASCADE'),
        nullable=False
    )
    assetid = db.Column(
        db.Integer,
        db.ForeignKey('assets.assetid', ondelete='CASCADE'),
        nullable=False
    )
    value = db.Column(db.Text)

    field = db.relationship('CustomField')

    __table_args__ = (
        db.UniqueConstraint('fieldid', 'assetid', name='uq_customfieldvalue_field_asset'),
    )

    def to_dict(self):
        return {
            'valueid': self.valueid,
            'fieldid': self.fieldid,
            'assetid': self.assetid,
            'value': self.value,
        }
