from __future__ import annotations

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


def _fmt_dur(seconds: float) -> str:
    if seconds is None or seconds < 0:
        return ""
    s = int(seconds)
    if s < 60:
        return f"{s}s"
    m, s = divmod(s, 60)
    if m < 60:
        return f"{m}m{s:02d}s" if s else f"{m}m"
    h, m = divmod(m, 60)
    if h < 24:
        return f"{h}h{m:02d}m" if m else f"{h}h"
    d, h = divmod(h, 24)
    return f"{d}d{h:02d}h"


def _parse_ts(s: str | None) -> datetime | None:
    if not s:
        return None
    try:
        return datetime.fromisoformat(s.replace("Z", "+00:00"))
    except Exception:
        return None


def _job_duration_s(job: sqlite3.Row) -> int:
    start = _parse_ts(job["started_at"])
    end = _parse_ts(job["finished_at"]) or datetime.now(timezone.utc)
    if not start:
        return 0
    if start.tzinfo is None:
        start = start.replace(tzinfo=timezone.utc)
    if end.tzinfo is None:
        end = end.replace(tzinfo=timezone.utc)
    return int((end - start).total_seconds())

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);

        CREATE TABLE IF NOT EXISTS stitches (
            id               INTEGER PRIMARY KEY,
            acquisition_id   INTEGER NOT NULL REFERENCES acquisitions(id) ON DELETE CASCADE,
            level            TEXT NOT NULL DEFAULT 'per_auv',
            auv              TEXT,
            input_job_ids    TEXT NOT NULL DEFAULT '[]',
            input_stitch_ids TEXT NOT NULL DEFAULT '[]',
            output_ply       TEXT,
            status           TEXT NOT NULL DEFAULT 'queued',
            worker_host      TEXT,
            started_at       TEXT,
            finished_at      TEXT,
            error            TEXT,
            created_at       TEXT NOT NULL DEFAULT (datetime('now'))
        );

        CREATE INDEX IF NOT EXISTS stitches_acq_idx ON stitches(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")


def _build_acquisitions():
    with closing(db()) as conn:
        acqs = conn.execute(
            "SELECT * FROM acquisitions ORDER BY created_at DESC"
        ).fetchall()
        jobs = conn.execute(
            "SELECT * FROM jobs ORDER BY auv, gopro_serial, segment_label"
        ).fetchall()
        stitches = conn.execute(
            "SELECT * FROM stitches ORDER BY level DESC, auv"
        ).fetchall()

    by_acq: dict[int, list[dict]] = {}
    by_acq_total: dict[int, int] = {}
    for j in jobs:
        d = dict(j)
        dur_s = _job_duration_s(j)
        d["_duration"] = _fmt_dur(dur_s)
        by_acq.setdefault(j["acquisition_id"], []).append(d)
        by_acq_total[j["acquisition_id"]] = by_acq_total.get(j["acquisition_id"], 0) + dur_s

    stitches_by_acq: dict[int, list[dict]] = {}
    for s in stitches:
        d = dict(s)
        start = _parse_ts(s["started_at"])
        end = _parse_ts(s["finished_at"]) or (
            datetime.now(timezone.utc) if s["status"] == "running" else None
        )
        if start and end:
            if start.tzinfo is None:
                start = start.replace(tzinfo=timezone.utc)
            if end.tzinfo is None:
                end = end.replace(tzinfo=timezone.utc)
            d["_duration"] = _fmt_dur(int((end - start).total_seconds()))
        else:
            d["_duration"] = ""
        stitches_by_acq.setdefault(s["acquisition_id"], []).append(d)

    return [
        {
            "id": acq["id"],
            "name": acq["name"],
            "source_path": acq["source_path"],
            "jobs": by_acq.get(acq["id"], []),
            "stitches": stitches_by_acq.get(acq["id"], []),
            "total_duration": _fmt_dur(by_acq_total.get(acq["id"], 0)),
        }
        for acq in acqs
    ]


@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    acquisitions = _build_acquisitions()
    return templates.TemplateResponse("index.html", {
        "request": request,
        "acquisitions": acquisitions,
        "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):
    return templates.TemplateResponse(
        "_jobs_table.html",
        {"request": request, "acquisitions": _build_acquisitions()},
    )


@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}


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


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