Aegis/backend/app/routers/evidence.py

"""Evidence upload, download, listing and deletion router — v2 with Red/Blue separation.

Endpoints
---------
POST   /tests/{test_id}/evidence       — upload evidence (with team=red/blue)
GET    /tests/{test_id}/evidence       — list evidences (filterable by team)
GET    /evidence/{id}                  — presigned download URL
DELETE /evidence/{id}                  — delete evidence (only in editable states)

Access Control
--------------
- Red Team (``red_tech``) can only upload ``team=red`` when test is in
  ``draft`` or ``red_executing``.
- Blue Team (``blue_tech``) can only upload ``team=blue`` when test is in
  ``blue_evaluating``.
- Admin can upload any team in any state.
- DELETE is restricted: red evidence in ``draft``/``red_executing``,
  blue evidence in ``blue_evaluating``.  No deletions in ``in_review``,
  ``validated``, or ``rejected``.
"""

import hashlib
import os
import uuid as _uuid
from typing import Optional

from fastapi import APIRouter, Depends, File, Form, Query, Request, UploadFile, status
from sqlalchemy.orm import Session

from app.database import get_db
from app.dependencies.auth import get_current_user
from app.domain.unit_of_work import UnitOfWork
from app.limiter import limiter
from app.models.enums import TeamSide
from app.models.evidence import Evidence
from app.models.user import User
from app.schemas.evidence import EvidenceOut
from app.services.audit_service import log_action
from app.services.evidence_service import (
    MAX_UPLOAD_SIZE,
    get_evidence_or_raise,
    get_test_or_raise,
    list_evidence_for_test,
    validate_delete_permission,
    validate_file,
    validate_upload_permission,
)
from app.storage import get_presigned_url, upload_file

router = APIRouter(tags=["evidence"])


# ---------------------------------------------------------------------------
# Helpers (router-specific: infrastructure / HTTP concerns)
# ---------------------------------------------------------------------------

def _evidence_to_out(evidence: Evidence) -> EvidenceOut:
    """Convert an ORM ``Evidence`` to the API schema, injecting a presigned URL."""
    return EvidenceOut(
        id=evidence.id,
        test_id=evidence.test_id,
        file_name=evidence.file_name,
        sha256_hash=evidence.sha256_hash,
        uploaded_by=evidence.uploaded_by,
        uploaded_at=evidence.uploaded_at,
        team=evidence.team,
        notes=evidence.notes,
        download_url=get_presigned_url(evidence.file_path),
    )


# ---------------------------------------------------------------------------
# POST /tests/{test_id}/evidence  —  upload with team
# ---------------------------------------------------------------------------


@router.post(
    "/tests/{test_id}/evidence",
    response_model=EvidenceOut,
    status_code=status.HTTP_201_CREATED,
)
@limiter.limit("10/minute")
async def upload_evidence(
    request: Request,
    test_id: _uuid.UUID,
    file: UploadFile = File(...),
    team: TeamSide = Form(TeamSide.red),
    notes: Optional[str] = Form(None),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> EvidenceOut:
    """Upload a file as evidence for the given test.

    The ``team`` field (sent as form data) determines whether this is
    Red Team (attack) or Blue Team (detection) evidence.
    """
    test = get_test_or_raise(db, test_id)
    validate_upload_permission(test, team, current_user.role)

    file_name = file.filename or "unnamed"
    content = await file.read(MAX_UPLOAD_SIZE + 1)
    validate_file(file_name, len(content))

    # Hash
    sha256 = hashlib.sha256(content).hexdigest()

    # 4. Object key (sanitise filename to prevent path traversal in storage)
    safe_name = os.path.basename(file_name)
    key = f"{test_id}/{_uuid.uuid4()}_{safe_name}"

    # 5. Upload to MinIO
    upload_file(content, key)

    # 6. Persist metadata and audit
    with UnitOfWork(db) as uow:
        evidence = Evidence(
            test_id=test_id,
            file_name=safe_name,
            file_path=key,
            sha256_hash=sha256,
            uploaded_by=current_user.id,
            team=team,
            notes=notes,
        )
        db.add(evidence)
        db.flush()  # Get evidence.id for audit
        log_action(
            db,
            user_id=current_user.id,
            action="upload_evidence",
            entity_type="evidence",
            entity_id=evidence.id,
            details={
                "file_name": safe_name,
                "sha256": sha256,
                "test_id": str(test_id),
                "team": team.value,
            },
        )
        uow.commit()
    db.refresh(evidence)

    return _evidence_to_out(evidence)


# ---------------------------------------------------------------------------
# GET /tests/{test_id}/evidence  —  list (with optional team filter)
# ---------------------------------------------------------------------------


@router.get("/tests/{test_id}/evidence", response_model=list[EvidenceOut])
def list_evidence(
    test_id: _uuid.UUID,
    team: Optional[str] = Query(None, description="Filter by team: red or blue"),
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> list[EvidenceOut]:
    """List all evidences for a test, optionally filtered by team."""
    get_test_or_raise(db, test_id)
    evidences = list_evidence_for_test(db, test_id, team=team)
    return [_evidence_to_out(e) for e in evidences]


# ---------------------------------------------------------------------------
# GET /evidence/{id}  —  presigned download URL
# ---------------------------------------------------------------------------


@router.get("/evidence/{evidence_id}", response_model=EvidenceOut)
def get_evidence(
    evidence_id: _uuid.UUID,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> EvidenceOut:
    """Return evidence metadata together with a presigned download URL."""
    evidence = get_evidence_or_raise(db, evidence_id)
    return _evidence_to_out(evidence)


# ---------------------------------------------------------------------------
# DELETE /evidence/{id}  —  delete evidence (editable states only)
# ---------------------------------------------------------------------------


@router.delete("/evidence/{evidence_id}", status_code=status.HTTP_200_OK)
def delete_evidence(
    evidence_id: _uuid.UUID,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
) -> dict:
    """Delete an evidence record.

    Only allowed in editable states:
    - Red evidence: ``draft``, ``red_executing``
    - Blue evidence: ``blue_evaluating``
    - No deletions in ``in_review``, ``validated``, ``rejected``
    """
    evidence = get_evidence_or_raise(db, evidence_id)
    test = get_test_or_raise(db, evidence.test_id)
    validate_delete_permission(test, evidence, current_user.role, current_user.id)

    with UnitOfWork(db) as uow:
        log_action(
            db,
            user_id=current_user.id,
            action="delete_evidence",
            entity_type="evidence",
            entity_id=evidence.id,
            details={
                "file_name": evidence.file_name,
                "test_id": str(evidence.test_id),
                "team": evidence.team.value if evidence.team else None,
            },
        )
        db.delete(evidence)
        uow.commit()

    return {"detail": "Evidence deleted"}