"""
app/api/stats.py
----------------
Mobile API endpoint for dashboard statistics.

GET /api/v1/stats/dashboard
    Returns inspector-scoped counts used by the iPad dashboard card:
    - today_inspections  : inspections started or completed today
    - completed_today    : completed inspections today
    - open_issues        : open + in_progress issues in contracted facilities
    - avg_score_30d      : average overall_score (last 30 days, own inspections)
    - pending_followups  : completed inspections with follow_up_required and no
                           child re-inspection yet
    - sla_breached       : open/in-progress issues past their SLA deadline
    - sla_at_risk        : open/in-progress issues past 75% of SLA window

    Admins and directors receive org-wide numbers (no facility scoping).
    Project managers receive unscoped numbers same as admin.
    Inspectors receive numbers scoped to their contracted facilities / own work.
    Customers are denied (403) — stats are for operational staff only.
"""

import logging
from datetime import timedelta

from flask import Blueprint, g
from sqlalchemy import func

from app import db
from app.models.inspection import Inspection
from app.models.issue import Issue
from app.models.facility import Area
from app.api.errors import api_ok, api_error
from app.api.decorators import jwt_required
from app.utils.scope import get_inspector_scope
from app.utils.sla import sla_status
from app.utils.time_utils import now_eastern

logger = logging.getLogger(__name__)

bp = Blueprint('api_stats', __name__)

_ALLOWED_ROLES = {'admin', 'director', 'inspector', 'external_inspector',
                  'project_manager', 'auditor'}


@bp.route('/stats/dashboard', methods=['GET'])
@jwt_required
def dashboard_stats():
    """
    Return dashboard KPI counts for the authenticated user.

    Response 200
    ------------
    {
        "ok": true,
        "data": {
            "today_inspections":  3,
            "completed_today":    2,
            "open_issues":        7,
            "avg_score_30d":      84.5,
            "pending_followups":  1,
            "sla_breached":       2,
            "sla_at_risk":        1
        }
    }
    """
    user = g.api_user

    if user.role not in _ALLOWED_ROLES:
        return api_error('Access denied', 403)

    now             = now_eastern()
    today_start     = now.replace(hour=0, minute=0, second=0, microsecond=0)
    today_end       = today_start + timedelta(days=1)
    thirty_days_ago = now - timedelta(days=30)

    is_inspector = user.is_inspector
    fids = get_inspector_scope(user) if is_inspector else None  # None = no scoping

    # ── Today's inspections ───────────────────────────────────────────────
    today_q = Inspection.query.filter(
        Inspection.inspection_date >= today_start,
        Inspection.inspection_date <  today_end,
    )
    if is_inspector:
        if not fids:
            today_q = today_q.filter(False)
        else:
            today_q = today_q.filter(
                Inspection.facility_id.in_(fids),
                Inspection.inspector_id == user.id,
            )

    today_inspections = today_q.count()

    completed_today = today_q.filter(
        Inspection.status == 'completed'
    ).count()

    # ── Open issues ───────────────────────────────────────────────────────
    open_q = Issue.query.filter(Issue.status.in_(['open', 'in_progress']))
    if is_inspector:
        if not fids:
            open_q = open_q.filter(False)
        else:
            open_q = open_q.outerjoin(Area, Issue.area_id == Area.id).filter(
                db.or_(
                    Issue.facility_id.in_(fids),
                    db.and_(Issue.area_id.isnot(None), Area.facility_id.in_(fids)),
                )
            )

    open_issues_all = open_q.all()
    open_issues     = len(open_issues_all)

    # ── Severity breakdown (derived from the same open_issues_all list) ───
    severity_breakdown = {
        'critical': sum(1 for i in open_issues_all if i.severity == 'critical'),
        'high':     sum(1 for i in open_issues_all if i.severity == 'high'),
        'medium':   sum(1 for i in open_issues_all if i.severity == 'medium'),
        'low':      sum(1 for i in open_issues_all if i.severity == 'low'),
    }

    # ── SLA counts (derived from the same open_issues_all list) ──────────
    sla_breached = sum(1 for i in open_issues_all if sla_status(i) == 'breached')
    sla_at_risk  = sum(1 for i in open_issues_all if sla_status(i) == 'at_risk')

    # ── Average score last 30 days ────────────────────────────────────────
    score_q = db.session.query(func.avg(Inspection.overall_score)).filter(
        Inspection.status          == 'completed',
        Inspection.overall_score.isnot(None),
        Inspection.inspection_date >= thirty_days_ago,
    )
    if is_inspector:
        if not fids:
            score_q = score_q.filter(False)
        else:
            score_q = score_q.filter(
                Inspection.facility_id.in_(fids),
                Inspection.inspector_id == user.id,
            )
    raw_avg   = score_q.scalar()
    avg_score = round(float(raw_avg), 1) if raw_avg is not None else None

    # ── Pending follow-ups ────────────────────────────────────────────────
    # Completed inspections that still need a re-inspection and have none yet.
    followup_q = Inspection.query.filter_by(
        follow_up_required=True, status='completed'
    ).filter(~Inspection.follow_ups.any())
    if is_inspector:
        if not fids:
            followup_q = followup_q.filter(False)
        else:
            followup_q = followup_q.filter(
                Inspection.facility_id.in_(fids),
                Inspection.inspector_id == user.id,
            )
    pending_followups = followup_q.count()

    logger.info(
        'API STATS | dashboard | user=%s | role=%s | '
        'today=%d | open_issues=%d | avg=%.1f | followups=%d | sla_b=%d | sla_r=%d',
        user.username, user.role,
        today_inspections, open_issues,
        avg_score or 0.0,
        pending_followups, sla_breached, sla_at_risk,
    )

    return api_ok({
        'today_inspections':  today_inspections,
        'completed_today':    completed_today,
        'open_issues':        open_issues,
        'avg_score_30d':      avg_score,
        'pending_followups':  pending_followups,
        'sla_breached':       sla_breached,
        'sla_at_risk':        sla_at_risk,
        'severity_breakdown': severity_breakdown,
    })