from typing import Any

from sqlalchemy import func, select
from sqlalchemy.orm import Session

from app.modules.approvals.constants import ApprovalStatus
from app.modules.approvals.models import ApprovalRequest
from app.modules.audit.models import AuditLog
from app.modules.business.constants import DONE_STATUSES, PROJECT_CLOSED_STATUSES, StatusValue
from app.modules.business.models import Project, RiskEvent, WorkReport, WorkTask
from app.modules.business.service import serialize_model
from app.modules.risk.service import RiskService


class DashboardService:
    """Build lightweight operational dashboard data for V2."""

    def __init__(self, db: Session):
        self.db = db
        self.risks = RiskService(db)

    def summary(self) -> dict[str, Any]:
        active_projects = self._count(Project, Project.status.notin_(PROJECT_CLOSED_STATUSES))
        open_tasks = self._count(WorkTask, WorkTask.status.notin_(DONE_STATUSES))
        pending_approvals = self._count(
            ApprovalRequest,
            ApprovalRequest.status == ApprovalStatus.PENDING,
        )
        open_risk_events = self._count(RiskEvent, RiskEvent.status == StatusValue.OPEN)
        latest_reports = self.db.execute(
            select(WorkReport).order_by(WorkReport.id.desc()).limit(5)
        ).scalars()
        latest_audit_logs = self.db.execute(
            select(AuditLog).order_by(AuditLog.id.desc()).limit(10)
        ).scalars()
        risk_summary = self.risks.summary()
        return {
            "metrics": {
                "active_projects": active_projects,
                "open_tasks": open_tasks,
                "pending_approvals": pending_approvals,
                "open_risk_events": open_risk_events,
                "risk_level": risk_summary["risk_level"],
                "risk_score": float(risk_summary["risk_score"]),
            },
            "risk_counts": {
                "overdue_tasks": len(risk_summary["overdue_tasks"]),
                "delayed_projects": len(risk_summary["delayed_projects"]),
                "over_budget_projects": len(risk_summary["over_budget_projects"]),
                "fund_risks": len(risk_summary["fund_risks"]),
                "supplier_risks": len(risk_summary["supplier_risks"]),
            },
            "latest_reports": [serialize_model(item) for item in latest_reports],
            "latest_audit_logs": [serialize_model(item) for item in latest_audit_logs],
        }

    def _count(self, model: type, *conditions: Any) -> int:
        stmt = select(func.count()).select_from(model)
        for condition in conditions:
            stmt = stmt.where(condition)
        return int(self.db.execute(stmt).scalar() or 0)