"""
File change model for tracking file operations during work sessions.

This model records all file modifications, creations, deletions, and renames
performed during work sessions.
"""

from datetime import datetime
from typing import Optional

from sqlalchemy import CHAR, CheckConstraint, ForeignKey, Index, Integer, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.sql import func

from api.models.base import Base, UUIDMixin


class FileChange(UUIDMixin, Base):
    """
    Track file changes during work sessions.

    Records all file operations including creations, modifications, deletions,
    renames, and backups performed during work items.

    Attributes:
        id: UUID primary key
        work_item_id: Reference to the work item
        session_id: Reference to the session
        file_path: Path to the file that was changed
        change_type: Type of change (created, modified, deleted, renamed, backed_up)
        backup_path: Path to backup if one was created
        size_bytes: File size in bytes
        description: Description of the change
        created_at: When the change was recorded
    """

    __tablename__ = "file_changes"

    # Foreign keys
    work_item_id: Mapped[str] = mapped_column(
        CHAR(36),
        ForeignKey("work_items.id", ondelete="CASCADE"),
        nullable=False,
        doc="Reference to work item",
    )
    session_id: Mapped[str] = mapped_column(
        CHAR(36),
        ForeignKey("sessions.id", ondelete="CASCADE"),
        nullable=False,
        doc="Reference to session",
    )

    # File details
    file_path: Mapped[str] = mapped_column(
        String(1000),
        nullable=False,
        doc="Path to the file that was changed",
    )
    change_type: Mapped[Optional[str]] = mapped_column(
        String(50),
        nullable=True,
        doc="Type of change",
    )
    backup_path: Mapped[Optional[str]] = mapped_column(
        String(1000),
        nullable=True,
        doc="Path to backup file if created",
    )
    size_bytes: Mapped[Optional[int]] = mapped_column(
        Integer,
        nullable=True,
        doc="File size in bytes",
    )
    description: Mapped[Optional[str]] = mapped_column(
        Text,
        nullable=True,
        doc="Description of the change",
    )

    # Timestamp
    created_at: Mapped[datetime] = mapped_column(
        nullable=False,
        server_default=func.now(),
        doc="When the change was recorded",
    )

    # Table constraints
    __table_args__ = (
        CheckConstraint(
            "change_type IN ('created', 'modified', 'deleted', 'renamed', 'backed_up')",
            name="ck_file_changes_type",
        ),
        Index("idx_file_changes_work_item", "work_item_id"),
        Index("idx_file_changes_session", "session_id"),
    )

    def __repr__(self) -> str:
        """String representation of the file change."""
        return f"<FileChange(id={self.id}, file={self.file_path}, type={self.change_type})>"