"""SQLAlchemy models for config backup tables."""

import uuid
from datetime import datetime

from sqlalchemy import (
    Boolean,
    DateTime,
    ForeignKey,
    Integer,
    LargeBinary,
    SmallInteger,
    String,
    Text,
    UniqueConstraint,
    func,
)
from sqlalchemy.dialects.postgresql import UUID
from sqlalchemy.orm import Mapped, mapped_column

from app.database import Base


class ConfigBackupRun(Base):
    """Metadata for a single config backup run.

    The actual config content (export.rsc and backup.bin) lives in the tenant's
    bare git repository at GIT_STORE_PATH/{tenant_id}.git. This table provides
    the timeline view and per-run metadata without duplicating file content in
    PostgreSQL.
    """

    __tablename__ = "config_backup_runs"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
        server_default=func.gen_random_uuid(),
    )
    device_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("devices.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tenants.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    # Git commit hash in the tenant's bare repo where this backup is stored.
    commit_sha: Mapped[str] = mapped_column(Text, nullable=False)
    # Trigger type: 'scheduled' | 'manual' | 'pre-restore' | 'checkpoint' | 'config-change'
    trigger_type: Mapped[str] = mapped_column(String(20), nullable=False)
    # Lines added/removed vs the prior export.rsc for this device.
    # NULL for the first backup (no prior version to diff against).
    lines_added: Mapped[int | None] = mapped_column(Integer, nullable=True)
    lines_removed: Mapped[int | None] = mapped_column(Integer, nullable=True)
    # Encryption metadata: NULL=plaintext, 1=client-side AES-GCM, 2=OpenBao Transit
    encryption_tier: Mapped[int | None] = mapped_column(SmallInteger, nullable=True)
    # 12-byte AES-GCM nonce for Tier 1 (client-side) backups; NULL for plaintext/Transit
    encryption_nonce: Mapped[bytes | None] = mapped_column(LargeBinary, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )

    def __repr__(self) -> str:
        return (
            f"<ConfigBackupRun id={self.id} device_id={self.device_id} "
            f"trigger={self.trigger_type!r} sha={self.commit_sha[:8]!r}>"
        )


class ConfigBackupSchedule(Base):
    """Per-tenant default and per-device override backup schedule config.

    A row with device_id=NULL is the tenant-level default (daily at 2am).
    A row with a specific device_id overrides the tenant default for that device.
    """

    __tablename__ = "config_backup_schedules"
    __table_args__ = (
        UniqueConstraint("tenant_id", "device_id", name="uq_backup_schedule_tenant_device"),
    )

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
        server_default=func.gen_random_uuid(),
    )
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tenants.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    # NULL = tenant-level default schedule; non-NULL = device-specific override.
    device_id: Mapped[uuid.UUID | None] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("devices.id", ondelete="CASCADE"),
        nullable=True,
    )
    # Standard cron expression (5 fields). Default: daily at 2am UTC.
    cron_expression: Mapped[str] = mapped_column(
        String(100),
        nullable=False,
        default="0 2 * * *",
        server_default="0 2 * * *",
    )
    enabled: Mapped[bool] = mapped_column(
        Boolean,
        nullable=False,
        default=True,
        server_default="TRUE",
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )

    def __repr__(self) -> str:
        scope = f"device={self.device_id}" if self.device_id else f"tenant={self.tenant_id}"
        return (
            f"<ConfigBackupSchedule {scope} cron={self.cron_expression!r} enabled={self.enabled}>"
        )


class ConfigPushOperation(Base):
    """Tracks pending two-phase config push operations for panic-revert recovery.

    Before pushing a config, a row is inserted with status='pending_verification'.
    If the API pod restarts during the 60-second verification window, the startup
    handler checks this table and either commits (deletes the RouterOS scheduler
    job) or marks the operation as 'failed'. This prevents the panic-revert
    scheduler from firing and reverting a successful push after an API restart.

    See Pitfall 6 in 04-RESEARCH.md for the full failure scenario.
    """

    __tablename__ = "config_push_operations"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
        server_default=func.gen_random_uuid(),
    )
    device_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("devices.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tenants.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    # Git commit SHA we'd revert to if the push fails.
    pre_push_commit_sha: Mapped[str] = mapped_column(Text, nullable=False)
    # RouterOS scheduler job name created on the device for panic-revert.
    scheduler_name: Mapped[str] = mapped_column(String(255), nullable=False)
    # 'pending_verification' | 'committed' | 'reverted' | 'failed'
    status: Mapped[str] = mapped_column(
        String(30),
        nullable=False,
        default="pending_verification",
        server_default="pending_verification",
    )
    started_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )
    completed_at: Mapped[datetime | None] = mapped_column(
        DateTime(timezone=True),
        nullable=True,
    )

    def __repr__(self) -> str:
        return (
            f"<ConfigPushOperation id={self.id} device_id={self.device_id} status={self.status!r}>"
        )


class RouterConfigSnapshot(Base):
    """A point-in-time router configuration snapshot.

    The config_text column stores OpenBao Transit ciphertext (vault:v1:...).
    Plaintext router config is NEVER stored in PostgreSQL -- it is encrypted
    via Transit before insertion and decrypted on read.

    The sha256_hash column stores the SHA-256 hex digest of the PLAINTEXT
    config (computed before encryption). This enables deduplication: if
    the hash matches the latest snapshot for a device, no new row is created.
    """

    __tablename__ = "router_config_snapshots"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
        server_default=func.gen_random_uuid(),
    )
    device_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("devices.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tenants.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    # OpenBao Transit ciphertext (vault:v1:...). Plaintext NEVER stored.
    config_text: Mapped[str] = mapped_column(Text, nullable=False)
    # SHA-256 hex digest of the PLAINTEXT config, for deduplication.
    sha256_hash: Mapped[str] = mapped_column(String(64), nullable=False)
    collected_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )

    def __repr__(self) -> str:
        return (
            f"<RouterConfigSnapshot id={self.id} device_id={self.device_id} "
            f"hash={self.sha256_hash[:8]!r}>"
        )


class RouterConfigDiff(Base):
    """Unified diff between two consecutive router config snapshots.

    Stores the diff_text (unified diff output) along with line counts
    for quick display without re-parsing. References both the old and
    new snapshot by foreign key.
    """

    __tablename__ = "router_config_diffs"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
        server_default=func.gen_random_uuid(),
    )
    device_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("devices.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tenants.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    old_snapshot_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("router_config_snapshots.id", ondelete="CASCADE"),
        nullable=False,
    )
    new_snapshot_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("router_config_snapshots.id", ondelete="CASCADE"),
        nullable=False,
    )
    diff_text: Mapped[str] = mapped_column(Text, nullable=False)
    lines_added: Mapped[int] = mapped_column(Integer, nullable=False, default=0, server_default="0")
    lines_removed: Mapped[int] = mapped_column(
        Integer, nullable=False, default=0, server_default="0"
    )
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )

    def __repr__(self) -> str:
        return (
            f"<RouterConfigDiff id={self.id} device_id={self.device_id} "
            f"+{self.lines_added}/-{self.lines_removed}>"
        )


class RouterConfigChange(Base):
    """A parsed change extracted from a router config diff.

    Each change represents a semantic modification (e.g., firewall rule
    added, IP address changed) parsed from the unified diff. The component
    field identifies the RouterOS section (e.g., 'ip/firewall/filter').
    """

    __tablename__ = "router_config_changes"

    id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        primary_key=True,
        default=uuid.uuid4,
        server_default=func.gen_random_uuid(),
    )
    diff_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("router_config_diffs.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    device_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("devices.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    tenant_id: Mapped[uuid.UUID] = mapped_column(
        UUID(as_uuid=True),
        ForeignKey("tenants.id", ondelete="CASCADE"),
        nullable=False,
        index=True,
    )
    # RouterOS config section path (e.g., 'ip/firewall/filter')
    component: Mapped[str] = mapped_column(Text, nullable=False)
    # Human-readable description of the change
    summary: Mapped[str] = mapped_column(Text, nullable=False)
    # Raw diff line(s), nullable for synthesized changes
    raw_line: Mapped[str | None] = mapped_column(Text, nullable=True)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        server_default=func.now(),
        nullable=False,
    )

    def __repr__(self) -> str:
        return (
            f"<RouterConfigChange id={self.id} diff_id={self.diff_id} component={self.component!r}>"
        )