"""Snapshot endpoints — coverage snapshots CRUD and comparison.

Provides periodic and manual snapshots of the organisation's coverage
state, plus temporal comparison between any two snapshots.
"""

# Import logging
import logging

# Import uuid
import uuid

# Import Optional from typing
from typing import Optional

# Import APIRouter, Depends, Query from fastapi
from fastapi import APIRouter, Depends, Query

# Import BaseModel from pydantic
from pydantic import BaseModel

# Import Session from sqlalchemy.orm
from sqlalchemy.orm import Session

# Import get_db from app.database
from app.database import get_db

# Import get_current_user, require_any_role, require_role from app.dependencies.auth
from app.dependencies.auth import get_current_user, require_any_role, require_role

# Import BusinessRuleViolation from app.domain.errors
from app.domain.errors import BusinessRuleViolation

# Import UnitOfWork from app.domain.unit_of_work
from app.domain.unit_of_work import UnitOfWork

# Import User from app.models.user
from app.models.user import User

# Import log_action from app.services.audit_service
from app.services.audit_service import log_action

# Import  from app.services.snapshot_service
from app.services.snapshot_service import (
    compare_snapshots,
    create_snapshot,
    delete_snapshot,
    get_coverage_evolution,
    get_snapshot_detail,
    get_snapshot_or_raise,
    serialize_snapshot_summary,
)

# Import  from app.services.snapshot_service
from app.services.snapshot_service import (
    list_snapshots as list_snapshots_svc,
)

# Assign logger = logging.getLogger(__name__)
logger = logging.getLogger(__name__)

# Assign router = APIRouter(prefix="/snapshots", tags=["snapshots"])
router = APIRouter(prefix="/snapshots", tags=["snapshots"])


# ── Pydantic schemas ─────────────────────────────────────────────────

class SnapshotCreate(BaseModel):
    """Payload for creating a new coverage snapshot."""

    # Assign name = None
    name: Optional[str] = None


# ---------------------------------------------------------------------------
# GET /snapshots — List snapshots (paginated)
# ---------------------------------------------------------------------------

@router.get("")
# Define function list_snapshots
def list_snapshots(
    # Entry: offset
    offset: int = Query(0, ge=0),
    # Entry: limit
    limit: int = Query(50, ge=1, le=200),
    # Entry: db
    db: Session = Depends(get_db),
    # Entry: current_user
    current_user: User = Depends(get_current_user),
) -> list:
    """List coverage snapshots ordered by creation date (newest first)."""
    # Return list_snapshots_svc(db, offset=offset, limit=limit)
    return list_snapshots_svc(db, offset=offset, limit=limit)


# ---------------------------------------------------------------------------
# POST /snapshots — Create snapshot manually
# ---------------------------------------------------------------------------

@router.post("", status_code=201)
# Define function create_snapshot_endpoint
def create_snapshot_endpoint(
    # Entry: payload
    payload: SnapshotCreate,
    # Entry: db
    db: Session = Depends(get_db),
    # Entry: current_user
    current_user: User = Depends(require_any_role("red_lead", "blue_lead", "admin")),
) -> dict:
    """Create a manual coverage snapshot with an optional name."""
    # Assign snapshot = create_snapshot(db, name=payload.name, user_id=current_user.id)
    snapshot = create_snapshot(db, name=payload.name, user_id=current_user.id)

    # Open context manager
    with UnitOfWork(db) as uow:
        # Call log_action()
        log_action(
            db,
            # Keyword argument: user_id
            user_id=current_user.id,
            # Keyword argument: action
            action="create_snapshot",
            # Keyword argument: entity_type
            entity_type="snapshot",
            # Keyword argument: entity_id
            entity_id=snapshot.id,
            # Keyword argument: details
            details={"name": snapshot.name, "score": snapshot.organization_score},
        )
        # Call uow.commit()
        uow.commit()

    # Return serialize_snapshot_summary(snapshot)
    return serialize_snapshot_summary(snapshot)


# ---------------------------------------------------------------------------
# GET /snapshots/evolution — Coverage trend over time
# ---------------------------------------------------------------------------


@router.get("/evolution")
# Define function coverage_evolution
def coverage_evolution(
    # Entry: months
    months: int = Query(12, ge=1, le=36),
    # Entry: db
    db: Session = Depends(get_db),
    # Entry: current_user
    current_user: User = Depends(get_current_user),
) -> list:
    """Return coverage snapshots for trend charts (last *months* months)."""
    # Return get_coverage_evolution(db, months=months)
    return get_coverage_evolution(db, months=months)


# ---------------------------------------------------------------------------
# GET /snapshots/compare — Compare two snapshots
# ---------------------------------------------------------------------------

@router.get("/compare")
# Define function compare_snapshots_endpoint
def compare_snapshots_endpoint(
    # Entry: a
    a: str = Query(..., description="Snapshot A ID"),
    # Entry: b
    b: str = Query(..., description="Snapshot B ID"),
    # Entry: db
    db: Session = Depends(get_db),
    # Entry: current_user
    current_user: User = Depends(get_current_user),
) -> dict:
    """Compare two snapshots showing improved, worsened, and unchanged techniques."""
    # Attempt the following; catch errors below
    try:
        # Assign a_id = uuid.UUID(a)
        a_id = uuid.UUID(a)
        # Assign b_id = uuid.UUID(b)
        b_id = uuid.UUID(b)
    # Handle ValueError
    except ValueError:
        # Raise BusinessRuleViolation
        raise BusinessRuleViolation("Invalid snapshot ID format")

    # Return compare_snapshots(db, a_id, b_id)
    return compare_snapshots(db, a_id, b_id)


# ---------------------------------------------------------------------------
# GET /snapshots/{id} — Snapshot detail
# ---------------------------------------------------------------------------

@router.get("/{snapshot_id}")
# Define function get_snapshot
def get_snapshot(
    # Entry: snapshot_id
    snapshot_id: str,
    # Entry: db
    db: Session = Depends(get_db),
    # Entry: current_user
    current_user: User = Depends(get_current_user),
) -> dict:
    """Get detailed snapshot information including per-technique states."""
    # Return get_snapshot_detail(db, snapshot_id)
    return get_snapshot_detail(db, snapshot_id)


# ---------------------------------------------------------------------------
# DELETE /snapshots/{id} — Delete snapshot (admin only)
# ---------------------------------------------------------------------------

@router.delete("/{snapshot_id}")
# Define function delete_snapshot_endpoint
def delete_snapshot_endpoint(
    # Entry: snapshot_id
    snapshot_id: str,
    # Entry: db
    db: Session = Depends(get_db),
    # Entry: current_user
    current_user: User = Depends(require_role("admin")),
) -> dict:
    """Delete a snapshot (admin only)."""
    # Assign snapshot = get_snapshot_or_raise(db, snapshot_id)
    snapshot = get_snapshot_or_raise(db, snapshot_id)

    # Open context manager
    with UnitOfWork(db) as uow:
        # Call log_action()
        log_action(
            db,
            # Keyword argument: user_id
            user_id=current_user.id,
            # Keyword argument: action
            action="delete_snapshot",
            # Keyword argument: entity_type
            entity_type="snapshot",
            # Keyword argument: entity_id
            entity_id=snapshot.id,
            # Keyword argument: details
            details={"name": snapshot.name},
        )
        # Call delete_snapshot()
        delete_snapshot(db, snapshot_id)
        # Call uow.commit()
        uow.commit()

    # Return {"detail": "Snapshot deleted"}
    return {"detail": "Snapshot deleted"}