"""Per-PC endpoint credentials, enrollment requests and migration waves.

  EndpointCredential
                 One row per asset. Holds only the sha256 of the secret the
                 agent was issued, plus a short display prefix. Revoking sets
                 revokedat; re-issuing after a revoke UPDATES the same row, so
                 an asset never carries two credentials. The row therefore also
                 says that this PC has enrolled at least once, which is how
                 agentauth tells a revoked PC from one that never enrolled:
                 plugin.endpoints.revokeddeniessharedkey refuses the shared key
                 to the first and never to the second. reenrollblocked keeps
                 a revoked PC from enrolling again (rolling it back to an agent
                 that only knows the shared key, or a compromised PC) until an
                 admin allows it.

  EndpointEnrollRequest
                 One row per (hostname, serial number) that asked to enroll -
                 the endpoint's identity, and the reason every contact from one
                 PC lands on one row. The agent's enrollment nonce is recorded
                 on first sight and is what an admin approval is bound to, so a
                 second machine claiming the same hostname and serial cannot
                 collect the approved credential. A REJECTED row binds to the
                 identity instead: any nonce from that hostname and serial stays
                 rejected, so a reinstall cannot argue its way back into the
                 queue. Only an admin approving the request clears it.

  EndpointMigrationWave
                 An admin action that pushed the agent upgrade to a set of PCs.
                 Progress is computed live from credentials and commands; only
                 the membership is stored.
"""

from datetime import datetime

from shopdb.api import db


def _utciso(value):
    return value.isoformat() + 'Z' if value else None


class EndpointCredential(db.Model):
    """The credential issued to one endpoint (hash only)."""

    __tablename__ = 'endpointcredentials'

    ENROLLED_AUTO = 'auto'
    ENROLLED_APPROVED = 'approved'

    credentialid = db.Column(db.Integer, primary_key=True)
    assetid = db.Column(
        db.Integer,
        db.ForeignKey('assets.assetid', ondelete='CASCADE'),
        nullable=False,
        unique=True,
    )
    credentialhash = db.Column(db.CHAR(64), nullable=False, unique=True)
    credentialprefix = db.Column(db.String(12), nullable=False)
    enrolledvia = db.Column(db.String(16), nullable=False)
    issuedat = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    lastusedat = db.Column(db.DateTime, nullable=True)
    revokedat = db.Column(db.DateTime, nullable=True)
    revokedby = db.Column(db.String(64), nullable=True)
    reenrollblocked = db.Column(db.Boolean, nullable=False, default=False,
                                server_default=db.false())
    reenrollblockedreason = db.Column(db.String(64), nullable=True)

    @property
    def isactive(self):
        return self.revokedat is None

    def to_dict(self):
        return {
            'credentialid': self.credentialid,
            'assetid': self.assetid,
            'credentialprefix': self.credentialprefix,
            'enrolledvia': self.enrolledvia,
            'issuedat': _utciso(self.issuedat),
            'lastusedat': _utciso(self.lastusedat),
            'revokedat': _utciso(self.revokedat),
            'revokedby': self.revokedby,
            'reenrollblocked': bool(self.reenrollblocked),
            'reenrollblockedreason': self.reenrollblockedreason,
        }

    def __repr__(self):
        return f'<EndpointCredential asset={self.assetid} {self.credentialprefix}>'


class EndpointEnrollRequest(db.Model):
    """A PC asking for a credential."""

    __tablename__ = 'endpointenrollrequests'

    STATUS_PENDING = 'pending'
    STATUS_APPROVED = 'approved'
    STATUS_REJECTED = 'rejected'
    STATUS_ISSUED = 'issued'

    requestid = db.Column(db.Integer, primary_key=True)
    hostname = db.Column(db.String(255), nullable=False)
    serialnumber = db.Column(db.String(128), nullable=False)
    deviceid = db.Column(db.String(64), nullable=True)
    enrollnonce = db.Column(db.String(128), nullable=False)
    agentversion = db.Column(db.String(32), nullable=True)
    status = db.Column(db.String(16), nullable=False, default=STATUS_PENDING)
    reason = db.Column(db.String(64), nullable=True)
    matchedassetid = db.Column(
        db.Integer,
        db.ForeignKey('assets.assetid', ondelete='SET NULL'),
        nullable=True,
    )
    sourceip = db.Column(db.String(45), nullable=True)
    requestedat = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    lastseenat = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    decidedat = db.Column(db.DateTime, nullable=True)
    decidedby = db.Column(db.String(64), nullable=True)

    # Prefix lengths keep the key under 767 bytes on utf8mb4 (4 bytes a char).
    __table_args__ = (
        db.Index('idx_endpointenrollrequests_hostserial', 'hostname',
                 'serialnumber',
                 mysql_length={'hostname': 128, 'serialnumber': 63}),
    )

    def to_dict(self):
        return {
            'requestid': self.requestid,
            'hostname': self.hostname,
            'serialnumber': self.serialnumber,
            'deviceid': self.deviceid,
            'agentversion': self.agentversion,
            'reason': self.reason,
            'status': self.status,
            'matchedassetid': self.matchedassetid,
            'requestedat': _utciso(self.requestedat),
            'lastseenat': _utciso(self.lastseenat),
            'decidedat': _utciso(self.decidedat),
            'decidedby': self.decidedby,
            'sourceip': self.sourceip,
        }

    def __repr__(self):
        return f'<EndpointEnrollRequest {self.hostname!r} {self.status}>'


class EndpointMigrationWave(db.Model):
    """One batch of agent upgrades pushed to move PCs onto credentials."""

    __tablename__ = 'endpointmigrationwaves'

    waveid = db.Column(db.Integer, primary_key=True)
    createdat = db.Column(db.DateTime, nullable=False, default=datetime.utcnow)
    createdby = db.Column(db.String(64), nullable=True)
    # Comma list of asset ids. TEXT, not JSON: MySQL 5.6.
    assetids = db.Column(db.Text, nullable=False, default='')
    notes = db.Column(db.String(255), nullable=True)

    @property
    def assetidlist(self):
        return [int(part) for part in (self.assetids or '').split(',')
                if part.strip().isdigit()]

    def __repr__(self):
        return f'<EndpointMigrationWave {self.waveid}>'