"""
Session model for tracking individual development sessions.
"""

from datetime import datetime
from typing import Optional, List, Dict, Any
from sqlalchemy import String, Text, Integer, DateTime, JSON, ForeignKey, Boolean
from sqlalchemy.orm import Mapped, mapped_column, relationship
from sqlalchemy.sql import func

from .base import Base, TimestampMixin


class Session(Base, TimestampMixin):
    """
    Represents an individual development session within a project.
    
    A session starts when Claude Code is launched or resumed and ends
    when the user stops or the session is interrupted.
    """
    
    __tablename__ = "sessions"
    
    # Primary key
    id: Mapped[int] = mapped_column(primary_key=True)
    
    # Foreign key to project
    project_id: Mapped[int] = mapped_column(ForeignKey("projects.id"), nullable=False, index=True)
    
    # Session timing
    start_time: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), 
        nullable=False, 
        default=func.now(),
        index=True
    )
    end_time: Mapped[Optional[datetime]] = mapped_column(DateTime(timezone=True), nullable=True)
    
    # Session metadata
    session_type: Mapped[str] = mapped_column(String(50), nullable=False)  # startup, resume, clear
    working_directory: Mapped[str] = mapped_column(Text, nullable=False)
    git_branch: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
    environment: Mapped[Optional[Dict[str, Any]]] = mapped_column(JSON, nullable=True)
    
    # Session statistics (updated as session progresses)
    duration_minutes: Mapped[Optional[int]] = mapped_column(Integer, nullable=True)
    activity_count: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    conversation_count: Mapped[int] = mapped_column(Integer, default=0, nullable=False)
    files_touched: Mapped[Optional[List[str]]] = mapped_column(JSON, nullable=True)
    
    # Relationships
    project: Mapped["Project"] = relationship("Project", back_populates="sessions")
    conversations: Mapped[List["Conversation"]] = relationship(
        "Conversation",
        back_populates="session", 
        cascade="all, delete-orphan",
        order_by="Conversation.timestamp"
    )
    activities: Mapped[List["Activity"]] = relationship(
        "Activity",
        back_populates="session",
        cascade="all, delete-orphan", 
        order_by="Activity.timestamp"
    )
    waiting_periods: Mapped[List["WaitingPeriod"]] = relationship(
        "WaitingPeriod",
        back_populates="session",
        cascade="all, delete-orphan",
        order_by="WaitingPeriod.start_time"
    )
    git_operations: Mapped[List["GitOperation"]] = relationship(
        "GitOperation",
        back_populates="session",
        cascade="all, delete-orphan",
        order_by="GitOperation.timestamp"
    )
    
    def __repr__(self) -> str:
        return f"<Session(id={self.id}, project_id={self.project_id}, type='{self.session_type}')>"
    
    @property
    def is_active(self) -> bool:
        """Check if this session is still active (not ended)."""
        return self.end_time is None
    
    @property
    def calculated_duration_minutes(self) -> Optional[int]:
        """Calculate session duration in minutes."""
        if self.end_time is None:
            # Session is still active, calculate current duration
            current_duration = datetime.utcnow() - self.start_time
            return int(current_duration.total_seconds() / 60)
        else:
            # Session is finished
            if self.duration_minutes is not None:
                return self.duration_minutes
            else:
                duration = self.end_time - self.start_time
                return int(duration.total_seconds() / 60)
    
    def end_session(self, end_reason: str = "normal") -> None:
        """End the session and calculate final statistics."""
        if self.end_time is None:
            self.end_time = func.now()
            self.duration_minutes = self.calculated_duration_minutes
            
            # Update project statistics
            if self.project:
                unique_files = len(set(self.files_touched or []))
                total_lines = sum(
                    (activity.lines_added or 0) + (activity.lines_removed or 0)
                    for activity in self.activities
                )
                self.project.update_stats(
                    session_duration_minutes=self.duration_minutes or 0,
                    files_count=unique_files,
                    lines_count=total_lines
                )
    
    def add_activity(self) -> None:
        """Increment activity counter."""
        self.activity_count += 1
        
    def add_conversation(self) -> None:
        """Increment conversation counter.""" 
        self.conversation_count += 1
        
    def add_file_touched(self, file_path: str) -> None:
        """Add a file to the list of files touched in this session."""
        if self.files_touched is None:
            self.files_touched = []
        
        if file_path not in self.files_touched:
            self.files_touched.append(file_path)