"""On-prem sync endpoint — polled by TapTrack every 30s to get SMS jobs and config."""
import uuid
from datetime import datetime, timezone
from fastapi import APIRouter, HTTPException, Request
from sqlalchemy.ext.asyncio import AsyncSession
from sqlalchemy import select, and_, update
from fastapi import Depends

from app.database import get_db
from app.models.license import License, LicenseStatus
from app.models.school import School, SchoolStatus
from app.models.sms import SmsJob, SmsJobStatus, SmsCreditLedger, SmsCreditTx

router = APIRouter(prefix="/api/sync", tags=["sync"])

# Feature flags by tier — mirrors licenses.py
def _tier_features(tier: str) -> dict:
    base = {"sms": True, "reports": True, "websocket": True, "multi_terminal": True}
    if tier == "premium":
        base.update({"api_keys": True, "webhooks": True, "bulk_enrollment": True})
    elif tier == "basic":
        base.update({"multi_terminal": False, "api_keys": False, "webhooks": False})
    return base

@router.post("/poll")
async def sync_poll(
    request: Request,
    db: AsyncSession = Depends(get_db),
):
    """
    Called by on-prem TapTrack every 30s.
    Returns pending SMS jobs and current config (sender_name, credits, feature flags).

    Body:
    {
      "license_key":     "TTUB-XXXXX-XXXXX-XXXXX",
      "report_sent_ids": ["uuid1", "uuid2"],   // confirmed-sent job IDs → deduct credits
      "job_failed_ids":  ["uuid3"]             // jobs on-prem could NOT deliver → retry/fail
    }
    """
    body = await request.json()
    key = body.get("license_key", "")
    sent_ids: list[str] = body.get("report_sent_ids", [])
    failed_ids: list[str] = body.get("job_failed_ids", [])

    # Validate license
    lic = (await db.execute(select(License).where(License.key == key))).scalar_one_or_none()
    if not lic or lic.status == LicenseStatus.revoked:
        raise HTTPException(403, detail={"reason": "revoked", "message": "Invalid or revoked license"})
    if lic.status == LicenseStatus.expired:
        raise HTTPException(403, detail={"reason": "expired", "message": "License has expired"})

    school = (await db.execute(select(School).where(School.id == lic.school_id))).scalar_one_or_none()
    if not school:
        raise HTTPException(404, detail="School not found")

    now = datetime.now(timezone.utc)

    # ── Mark completed jobs (on-prem confirmed delivery) ──────────────────────
    if sent_ids:
        # Fetch jobs to deduct credits (only for this school, only processing/pending)
        jobs_sent = (await db.execute(
            select(SmsJob).where(
                and_(
                    SmsJob.id.in_(sent_ids),
                    SmsJob.school_id == school.id,
                    SmsJob.status.in_([SmsJobStatus.processing, SmsJobStatus.pending]),
                )
            )
        )).scalars().all()

        if jobs_sent:
            credit_deductions = len(jobs_sent)
            new_balance = float(school.sms_credits) - credit_deductions
            new_balance = max(new_balance, 0.0)  # floor at 0

            # Deduct credits from school
            school.sms_credits = new_balance

            # Write a single consolidated ledger entry for this batch
            db.add(SmsCreditLedger(
                id=str(uuid.uuid4()),
                school_id=school.id,
                tx_type=SmsCreditTx.deduct,
                amount=-float(credit_deductions),
                balance_after=new_balance,
                description=f"SMS delivered via on-prem agent ({credit_deductions} messages)",
                reference_id=sent_ids[0] if len(sent_ids) == 1 else None,
            ))

            # Mark jobs as sent, tag delivered_via=pull
            await db.execute(
                update(SmsJob)
                .where(and_(SmsJob.id.in_([j.id for j in jobs_sent]), SmsJob.school_id == school.id))
                .values(status=SmsJobStatus.sent, sent_at=now, delivered_via="pull")
            )

            # Low credit alert — fire if below threshold
            if new_balance <= float(school.sms_credit_low_threshold):
                try:
                    from app.tasks.sms import send_low_credit_alert
                    send_low_credit_alert.delay(school.id)
                except Exception:
                    pass  # don't fail the poll if alert fails to queue

    # ── Handle jobs on-prem failed to send ────────────────────────────────────
    if failed_ids:
        failed_jobs = (await db.execute(
            select(SmsJob).where(
                and_(
                    SmsJob.id.in_(failed_ids),
                    SmsJob.school_id == school.id,
                )
            )
        )).scalars().all()

        for job in failed_jobs:
            job.retry_count = (job.retry_count or 0) + 1
            if job.retry_count >= 5:
                job.status = SmsJobStatus.failed
                job.error_message = "Max retries reached — on-prem delivery failed"
            else:
                # Return to pending so it can be re-dispatched (pull or push)
                job.status = SmsJobStatus.pending
                job.error_message = f"On-prem delivery failed (attempt {job.retry_count})"
                job.processing_started_at = None

    # ── Fetch pending jobs for this school ────────────────────────────────────
    # Suspended schools get an empty job list — on-prem should show banner
    pending_jobs: list[SmsJob] = []
    if school.status == SchoolStatus.active:
        pending_jobs = (await db.execute(
            select(SmsJob)
            .where(and_(SmsJob.school_id == school.id, SmsJob.status == SmsJobStatus.pending))
            .limit(50)
        )).scalars().all()

        # Mark dispatched jobs as processing
        if pending_jobs:
            job_ids = [j.id for j in pending_jobs]
            await db.execute(
                update(SmsJob)
                .where(SmsJob.id.in_(job_ids))
                .values(status=SmsJobStatus.processing, processing_started_at=now)
            )

    # ── Update license heartbeat ───────────────────────────────────────────────
    lic.last_validated_at = now
    lic.last_seen_ip = request.client.host if request.client else None

    await db.commit()

    suspended = school.status in (SchoolStatus.suspended, SchoolStatus.expired)

    return {
        "sms_jobs": [
            {
                "id": j.id,
                "recipient_phone": j.recipient_phone,
                "message": j.message,
                "sender_name": j.sender_name,
            }
            for j in pending_jobs
        ],
        "config": {
            "sms_sender_name": school.sms_sender_name,
            "sms_credits": float(school.sms_credits),
            "school_status": school.status.value,
            "suspended": suspended,
            "feature_flags": _tier_features(lic.tier),
        },
    }