"""
jobs.py - Lightweight async job registry for conflict checks.

A conflict check takes minutes, so the HTTP request must not block on it. Each
upload becomes a job that runs on a background thread; the client gets a job_id
immediately and can either poll GET /jobs/{id} or just close the page and wait
for the completion email.

State is in-memory (fine for a single-user tool); the report is also persisted
to outputs/<job_id>/ so results survive a restart even though live status does
not. No external queue/DB.
"""

import os
import time
import uuid
import shutil
import threading
from typing import Dict, Optional

from backend import config
from backend.agents.runner import run_agent_pipeline
from backend.pipeline.runner import run_pipeline
from backend.email_sender import send_conflict_report

_jobs: Dict[str, Dict] = {}
_lock = threading.Lock()
PIPELINE_MODES = {"classic", "agent"}


def _set(job_id: str, **fields) -> None:
    with _lock:
        _jobs[job_id].update(fields)


def create_job(pdf_path: str, source_filename: str, email: Optional[str] = None,
               project_input: Optional[Dict] = None, text_local: bool = False,
               pipeline_mode: str = "classic") -> str:
    """Register a job and kick off its background thread. Returns the job_id."""
    pipeline_mode = pipeline_mode.strip().lower()
    if pipeline_mode not in PIPELINE_MODES:
        raise ValueError(f"Unsupported pipeline mode: {pipeline_mode!r}")
    # Agent mode v1 is OpenRouter-only.
    text_local = bool(text_local and pipeline_mode == "classic")
    job_id = uuid.uuid4().hex[:12]
    with _lock:
        _jobs[job_id] = {
            "job_id": job_id,
            "status": "queued",          # queued -> running -> done | error
            "source": source_filename,
            "email": email or None,
            "project_input": project_input or {},
            "text_local": text_local,
            "pipeline_mode": pipeline_mode,
            "stage": None,
            "created_at": time.time(),
            "finished_at": None,
            "report": None,
            "error": None,
        }
    threading.Thread(target=_run, args=(
        job_id, pdf_path, project_input, text_local, pipeline_mode,
    ),
                     daemon=True).start()
    return job_id


def _run(job_id: str, pdf_path: str, project_input: Optional[Dict] = None,
         text_local: bool = False, pipeline_mode: str = "classic") -> None:
    out_dir = os.path.join(config.OUTPUT_DIR, job_id)
    try:
        _set(job_id, status="running")
        # Keep a copy of the source PDF so its sheets can be viewed later.
        os.makedirs(out_dir, exist_ok=True)
        shutil.copy2(pdf_path, os.path.join(out_dir, "source.pdf"))
        runner = run_agent_pipeline if pipeline_mode == "agent" else run_pipeline
        runner_kwargs = {
            "out_dir": out_dir,
            "on_stage": lambda name: _set(job_id, stage=name),
            "project_input": project_input,
            "source_name": _jobs[job_id].get("source"),
        }
        if pipeline_mode == "classic":
            runner_kwargs["text_local"] = text_local
        report = runner(pdf_path, **runner_kwargs)
        report.setdefault("summary", {})["pipeline_mode"] = pipeline_mode
        _set(job_id, status="done", report=report, finished_at=time.time(), stage=None)
        _notify(job_id, report, out_dir)
    except Exception as e:
        print(f"[Jobs] Job {job_id} failed: {e}")
        _set(job_id, status="error", error=str(e), finished_at=time.time())
        _notify_error(job_id)
    finally:
        try:
            os.remove(pdf_path)
        except OSError:
            pass


def _notify(job_id: str, report: Dict, out_dir: str) -> None:
    email = _jobs[job_id].get("email")
    if not email:
        return
    results_url = f"{config.APP_BASE_URL.rstrip('/')}/?job={job_id}"
    attachments = [
        os.path.join(out_dir, "report.md"),
        os.path.join(out_dir, "conflicts.json"),
        os.path.join(out_dir, "validated_issues.json"),
        os.path.join(out_dir, "rfis.json"),
    ]
    send_conflict_report(email, report, results_url=results_url, attachments=attachments)


def _notify_error(job_id: str) -> None:
    job = _jobs[job_id]
    email = job.get("email")
    if not email:
        return
    # Reuse the report mailer with a minimal error-shaped payload.
    err_report = {
        "source": job.get("source", ""),
        "summary": {"conflicts_found": 0, "by_severity": {}, "disciplines": []},
    }
    try:
        from backend.email_sender import _smtp_ready, _send
        from email.message import EmailMessage
        if not _smtp_ready():
            print(f"[Email] SMTP not configured - skipping error notice to {email}")
            return
        msg = EmailMessage()
        msg["Subject"] = f"Conflict Checker - {job.get('source','')} - run FAILED"
        msg["From"] = config.SMTP_FROM or config.SMTP_USER
        msg["To"] = email
        msg.set_content(
            "Your conflict check did not complete.\n\n"
            f"Drawing set: {job.get('source','')}\n"
            f"Error: {job.get('error','unknown')}\n\n"
            "Generated by Conflict Checker"
        )
        _send(msg)
    except Exception as e:
        print(f"[Email] Failed to send error notice: {e}")


def get_job(job_id: str) -> Optional[Dict]:
    """Public job view. Includes the full report only when done.

    Falls back to the on-disk conflicts.json when the job isn't in the
    in-memory registry (e.g. after a server restart).
    """
    with _lock:
        job = _jobs.get(job_id)
        if job:
            return dict(job)

    # Try loading from disk
    report_path = os.path.join(config.OUTPUT_DIR, job_id, "conflicts.json")
    if not os.path.isfile(report_path):
        return None
    try:
        import json
        with open(report_path, encoding="utf-8") as f:
            report = json.load(f)
        source_pdf = os.path.join(config.OUTPUT_DIR, job_id, "source.pdf")
        return {
            "job_id":       job_id,
            "status":       "done",
            "source":       report.get("source", os.path.basename(report_path)),
            "email":        None,
            "project_input": report.get("project_input", {}),
            "text_local":   report.get("summary", {}).get("text_backend") == "local",
            "pipeline_mode": report.get("summary", {}).get("pipeline_mode", "classic"),
            "stage":        None,
            "created_at":   os.path.getmtime(source_pdf) if os.path.isfile(source_pdf) else None,
            "finished_at":  os.path.getmtime(report_path),
            "report":       report,
            "error":        None,
        }
    except Exception as e:
        print(f"[Jobs] Failed to load job {job_id} from disk: {e}")
        return None