import uuid
from typing import List
from fastapi import APIRouter, Depends, HTTPException, status, Request
from sqlalchemy.orm import Session

from app.core.database import get_db
from app.models import User, Space, Project, TaskStatus, AuditAction
from app.models.task_status import DEFAULT_STATUSES
from app.schemas.project import ProjectCreate, ProjectUpdate, ProjectResponse, ProjectWithDetails
from app.schemas.task_status import TaskStatusResponse
from app.middleware.auth import (
    get_current_user, check_space_access, check_space_edit_access,
    check_project_access, check_project_edit_access
)
from app.middleware.audit import get_audit_metadata
from app.services.audit_service import AuditService

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


def create_default_statuses(db: Session, project_id: str):
    """Create default task statuses for a new project."""
    for status_data in DEFAULT_STATUSES:
        status = TaskStatus(
            id=str(uuid.uuid4()),
            project_id=project_id,
            **status_data
        )
        db.add(status)


@router.get("/api/spaces/{space_id}/projects", response_model=List[ProjectWithDetails])
async def list_projects_in_space(
    space_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    List all projects in a space that the user can access.
    """
    space = db.query(Space).filter(Space.id == space_id, Space.is_active == True).first()

    if not space:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Space not found",
        )

    if not check_space_access(current_user, space):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Access denied",
        )

    projects = db.query(Project).filter(Project.space_id == space_id).all()

    # Filter by project access
    accessible_projects = [p for p in projects if check_project_access(current_user, p)]

    result = []
    for project in accessible_projects:
        task_count = len(project.tasks) if project.tasks else 0
        result.append(ProjectWithDetails(
            id=project.id,
            space_id=project.space_id,
            title=project.title,
            description=project.description,
            owner_id=project.owner_id,
            budget=project.budget,
            start_date=project.start_date,
            end_date=project.end_date,
            security_level=project.security_level,
            status=project.status,
            department_id=project.department_id,
            created_at=project.created_at,
            updated_at=project.updated_at,
            owner_name=project.owner.name if project.owner else None,
            space_name=project.space.name if project.space else None,
            department_name=project.department.name if project.department else None,
            task_count=task_count,
        ))

    return result


@router.post("/api/spaces/{space_id}/projects", response_model=ProjectResponse, status_code=status.HTTP_201_CREATED)
async def create_project(
    space_id: str,
    project_data: ProjectCreate,
    request: Request,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    Create a new project in a space.
    """
    space = db.query(Space).filter(Space.id == space_id, Space.is_active == True).first()

    if not space:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Space not found",
        )

    if not check_space_access(current_user, space):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Access denied",
        )

    project = Project(
        id=str(uuid.uuid4()),
        space_id=space_id,
        title=project_data.title,
        description=project_data.description,
        owner_id=current_user.id,
        budget=project_data.budget,
        start_date=project_data.start_date,
        end_date=project_data.end_date,
        security_level=project_data.security_level.value if project_data.security_level else "department",
        department_id=project_data.department_id or current_user.department_id,
    )

    db.add(project)
    db.flush()  # Get the project ID

    # Create default task statuses
    create_default_statuses(db, project.id)

    # Audit log
    AuditService.log_event(
        db=db,
        event_type="project.create",
        resource_type="project",
        action=AuditAction.CREATE,
        user_id=current_user.id,
        resource_id=project.id,
        changes=[{"field": "title", "old_value": None, "new_value": project.title}],
        request_metadata=get_audit_metadata(request),
    )

    db.commit()
    db.refresh(project)

    return project


@router.get("/api/projects/{project_id}", response_model=ProjectWithDetails)
async def get_project(
    project_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    Get a project by ID.
    """
    project = db.query(Project).filter(Project.id == project_id).first()

    if not project:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Project not found",
        )

    if not check_project_access(current_user, project):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Access denied",
        )

    task_count = len(project.tasks) if project.tasks else 0

    return ProjectWithDetails(
        id=project.id,
        space_id=project.space_id,
        title=project.title,
        description=project.description,
        owner_id=project.owner_id,
        budget=project.budget,
        start_date=project.start_date,
        end_date=project.end_date,
        security_level=project.security_level,
        status=project.status,
        department_id=project.department_id,
        created_at=project.created_at,
        updated_at=project.updated_at,
        owner_name=project.owner.name if project.owner else None,
        space_name=project.space.name if project.space else None,
        department_name=project.department.name if project.department else None,
        task_count=task_count,
    )


@router.patch("/api/projects/{project_id}", response_model=ProjectResponse)
async def update_project(
    project_id: str,
    project_data: ProjectUpdate,
    request: Request,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    Update a project.
    """
    project = db.query(Project).filter(Project.id == project_id).first()

    if not project:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Project not found",
        )

    if not check_project_edit_access(current_user, project):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Only project owner can update",
        )

    # Capture old values for audit
    old_values = {
        "title": project.title,
        "description": project.description,
        "budget": project.budget,
        "start_date": project.start_date,
        "end_date": project.end_date,
        "security_level": project.security_level,
        "status": project.status,
    }

    # Update fields
    update_data = project_data.model_dump(exclude_unset=True)
    for field, value in update_data.items():
        if field == "security_level" and value:
            setattr(project, field, value.value)
        else:
            setattr(project, field, value)

    # Capture new values and log changes
    new_values = {
        "title": project.title,
        "description": project.description,
        "budget": project.budget,
        "start_date": project.start_date,
        "end_date": project.end_date,
        "security_level": project.security_level,
        "status": project.status,
    }

    changes = AuditService.detect_changes(old_values, new_values)
    if changes:
        AuditService.log_event(
            db=db,
            event_type="project.update",
            resource_type="project",
            action=AuditAction.UPDATE,
            user_id=current_user.id,
            resource_id=project.id,
            changes=changes,
            request_metadata=get_audit_metadata(request),
        )

    db.commit()
    db.refresh(project)

    return project


@router.delete("/api/projects/{project_id}", status_code=status.HTTP_204_NO_CONTENT)
async def delete_project(
    project_id: str,
    request: Request,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    Delete a project (hard delete, cascades to tasks).
    """
    project = db.query(Project).filter(Project.id == project_id).first()

    if not project:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Project not found",
        )

    if not check_project_edit_access(current_user, project):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Only project owner can delete",
        )

    # Audit log before deletion (this is a high-sensitivity event that triggers alert)
    AuditService.log_event(
        db=db,
        event_type="project.delete",
        resource_type="project",
        action=AuditAction.DELETE,
        user_id=current_user.id,
        resource_id=project.id,
        changes=[{"field": "title", "old_value": project.title, "new_value": None}],
        request_metadata=get_audit_metadata(request),
    )

    db.delete(project)
    db.commit()

    return None


@router.get("/api/projects/{project_id}/statuses", response_model=List[TaskStatusResponse])
async def list_project_statuses(
    project_id: str,
    db: Session = Depends(get_db),
    current_user: User = Depends(get_current_user),
):
    """
    List all task statuses for a project.
    """
    project = db.query(Project).filter(Project.id == project_id).first()

    if not project:
        raise HTTPException(
            status_code=status.HTTP_404_NOT_FOUND,
            detail="Project not found",
        )

    if not check_project_access(current_user, project):
        raise HTTPException(
            status_code=status.HTTP_403_FORBIDDEN,
            detail="Access denied",
        )

    statuses = db.query(TaskStatus).filter(
        TaskStatus.project_id == project_id
    ).order_by(TaskStatus.position).all()

    return statuses