from __future__ import annotations

import asyncio
import json
import os
import sqlite3
from contextlib import asynccontextmanager, closing
from datetime import datetime
from pathlib import Path
from typing import Any

from fastapi import FastAPI, Form, HTTPException, Request
from fastapi.responses import HTMLResponse, JSONResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates

DB_PATH = Path(os.environ.get("COSMA_QC_DB", "/var/lib/cosma-qc/jobs.db"))
WORKERS = json.loads(os.environ.get("COSMA_QC_WORKERS", json.dumps([
    {"host": "192.168.0.87", "ssh_alias": "gpu",     "gpu": "RTX 3060 12GB"},
    {"host": "192.168.0.84", "ssh_alias": "cosma-vm","gpu": "RTX 3090 24GB"},
])))

STATUSES = ("queued", "extracting", "running", "done", "error")


def db() -> sqlite3.Connection:
    DB_PATH.parent.mkdir(parents=True, exist_ok=True)
    conn = sqlite3.connect(DB_PATH, isolation_level=None)
    conn.execute("PRAGMA journal_mode=WAL")
    conn.execute("PRAGMA foreign_keys=ON")
    conn.row_factory = sqlite3.Row
    return conn


def init_schema() -> None:
    with closing(db()) as conn:
        conn.executescript("""
        CREATE TABLE IF NOT EXISTS acquisitions (
            id           INTEGER PRIMARY KEY,
            name         TEXT NOT NULL,
            source_path  TEXT NOT NULL,
            created_at   TEXT NOT NULL DEFAULT (datetime('now'))
        );

        CREATE TABLE IF NOT EXISTS jobs (
            id               INTEGER PRIMARY KEY,
            acquisition_id   INTEGER NOT NULL REFERENCES acquisitions(id) ON DELETE CASCADE,
            auv              TEXT NOT NULL,
            gopro_serial     TEXT NOT NULL,
            segment_label    TEXT NOT NULL,
            video_paths      TEXT NOT NULL,
            frame_count      INTEGER,
            frames_dir       TEXT,
            status           TEXT NOT NULL DEFAULT 'queued',
            worker_host      TEXT,
            viser_url        TEXT,
            ply_path         TEXT,
            progress         INTEGER NOT NULL DEFAULT 0,
            log_tail         TEXT,
            error            TEXT,
            started_at       TEXT,
            finished_at      TEXT,
            created_at       TEXT NOT NULL DEFAULT (datetime('now'))
        );

        CREATE INDEX IF NOT EXISTS jobs_status_idx ON jobs(status);
        CREATE INDEX IF NOT EXISTS jobs_acq_idx    ON jobs(acquisition_id);
        """)


@asynccontextmanager
async def lifespan(_: FastAPI):
    init_schema()
    yield


app = FastAPI(title="cosma-qc", lifespan=lifespan)
templates = Jinja2Templates(directory=Path(__file__).parent / "templates")
app.mount("/static", StaticFiles(directory=Path(__file__).parent / "static"), name="static")


@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    with closing(db()) as conn:
        jobs = conn.execute("""
            SELECT j.*, a.name AS acquisition_name
            FROM jobs j
            LEFT JOIN acquisitions a ON a.id = j.acquisition_id
            ORDER BY j.created_at DESC
            LIMIT 200
        """).fetchall()
    return templates.TemplateResponse("index.html", {
        "request": request,
        "jobs": jobs,
        "workers": WORKERS,
    })


@app.get("/api/jobs")
async def list_jobs():
    with closing(db()) as conn:
        rows = conn.execute("SELECT * FROM jobs ORDER BY created_at DESC LIMIT 500").fetchall()
    return [dict(r) for r in rows]


@app.get("/partials/jobs", response_class=HTMLResponse)
async def partial_jobs(request: Request):
    with closing(db()) as conn:
        jobs = conn.execute("""
            SELECT j.*, a.name AS acquisition_name
            FROM jobs j
            LEFT JOIN acquisitions a ON a.id = j.acquisition_id
            ORDER BY j.created_at DESC
            LIMIT 200
        """).fetchall()
    return templates.TemplateResponse("_jobs_table.html", {"request": request, "jobs": jobs})


@app.get("/partials/monitor", response_class=HTMLResponse)
async def partial_monitor(request: Request):
    stats = await asyncio.gather(*[_worker_stats(w) for w in WORKERS])
    return templates.TemplateResponse("_monitor.html", {"request": request, "workers": stats})


async def _worker_stats(worker: dict) -> dict:
    alias = worker["ssh_alias"]
    try:
        proc = await asyncio.create_subprocess_exec(
            "ssh", "-o", "ConnectTimeout=3", "-o", "BatchMode=yes", alias,
            "nvidia-smi --query-gpu=memory.used,memory.total,utilization.gpu --format=csv,noheader,nounits && df -h / | tail -1",
            stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE,
        )
        out, _ = await asyncio.wait_for(proc.communicate(), timeout=4)
        text = out.decode().strip().splitlines()
        gpu_line = text[0].split(",") if text else ["?", "?", "?"]
        disk = text[1].split() if len(text) > 1 else ["?"] * 6
        return {
            **worker,
            "online": True,
            "vram_used_mib": int(gpu_line[0].strip()) if gpu_line[0].strip().isdigit() else None,
            "vram_total_mib": int(gpu_line[1].strip()) if gpu_line[1].strip().isdigit() else None,
            "gpu_util_pct": int(gpu_line[2].strip()) if gpu_line[2].strip().isdigit() else None,
            "disk_used_pct": disk[4] if len(disk) > 4 else "?",
        }
    except Exception as e:
        return {**worker, "online": False, "error": str(e)[:80]}


@app.post("/jobs/{job_id}/cancel")
async def cancel_job(job_id: int):
    with closing(db()) as conn:
        conn.execute(
            "UPDATE jobs SET status='error', error='cancelled by user', finished_at=datetime('now') "
            "WHERE id=? AND status IN ('queued','extracting','running')",
            (job_id,),
        )
    return {"ok": True}


@app.post("/jobs/{job_id}/retry")
async def retry_job(job_id: int):
    with closing(db()) as conn:
        conn.execute(
            "UPDATE jobs SET status='queued', error=NULL, progress=0, started_at=NULL, "
            "finished_at=NULL, worker_host=NULL WHERE id=? AND status='error'",
            (job_id,),
        )
    return {"ok": True}