from fastapi import APIRouter, Depends
from sqlalchemy import func
from sqlalchemy.orm import Session

from ..auth import verify_token
from ..database import get_db
from ..models import NodeType, RequirementNode
from ..schemas import StatsResponse

router = APIRouter(prefix="/api/stats", tags=["stats"], dependencies=[Depends(verify_token)])


@router.get("", response_model=StatsResponse)
def get_stats(project_id: int | None = None, db: Session = Depends(get_db)):
    query = db.query(RequirementNode)
    if project_id is not None:
        query = query.filter(RequirementNode.project_id == project_id)

    nodes = query.all()
    total = len(nodes)

    by_type = {}
    by_status: dict[str, int] = {}
    by_priority: dict[str, int] = {}
    quality_passing = 0
    leaves_with_tests = 0
    total_leaves = 0

    for n in nodes:
        by_type[n.node_type.value] = by_type.get(n.node_type.value, 0) + 1
        by_status[n.status.value] = by_status.get(n.status.value, 0) + 1
        by_priority[n.priority.value] = by_priority.get(n.priority.value, 0) + 1

        if n.traceable and n.measurable and n.consistent and n.single_purpose:
            quality_passing += 1

        if n.node_type == NodeType.leaf:
            total_leaves += 1
            if n.test_spec:
                leaves_with_tests += 1

    coverage = (leaves_with_tests / total_leaves * 100) if total_leaves > 0 else 0.0

    return StatsResponse(
        total_nodes=total,
        pillars=by_type.get("pillar", 0),
        requirements=by_type.get("requirement", 0),
        sub_requirements=by_type.get("sub_requirement", 0),
        leaves=by_type.get("leaf", 0),
        by_status=by_status,
        by_priority=by_priority,
        quality_passing=quality_passing,
        quality_failing=total - quality_passing,
        coverage_percent=round(coverage, 1),
    )