"""
Jinja2 template engine + filter/helper registration.
Import `templates` from here — do not create additional Jinja2 instances.
"""

from datetime import datetime, timezone

from fastapi.templating import Jinja2Templates

templates = Jinja2Templates(directory="app/templates")


# ---------------------------------------------------------------------------
# Template filters
# ---------------------------------------------------------------------------

def _format_bytes(value: int | None) -> str:
    if value is None:
        return "—"
    tb = value / 1_000_000_000_000
    if tb >= 1:
        return f"{tb:.0f} TB"
    gb = value / 1_000_000_000
    return f"{gb:.0f} GB"


def _format_eta(seconds: int | None) -> str:
    if not seconds or seconds <= 0:
        return ""
    h = seconds // 3600
    m = (seconds % 3600) // 60
    if h > 0:
        return f"~{h}h {m}m" if m else f"~{h}h"
    return f"~{m}m" if m else "<1m"


def _temp_class(celsius: int | None) -> str:
    if celsius is None:
        return ""
    from app.config import settings
    if celsius < settings.temp_warn_c:
        return "temp-cool"
    if celsius < settings.temp_crit_c:
        return "temp-warm"
    return "temp-hot"


def _format_dt(iso: str | None) -> str:
    if not iso:
        return "—"
    try:
        dt = datetime.fromisoformat(iso)
        if dt.tzinfo is None:
            dt = dt.replace(tzinfo=timezone.utc)
        local = dt.astimezone()
        return local.strftime("%H:%M:%S")
    except Exception:
        return iso


def _format_dt_full(iso: str | None) -> str:
    """Date + time for history tables."""
    if not iso:
        return "—"
    try:
        dt = datetime.fromisoformat(iso)
        if dt.tzinfo is None:
            dt = dt.replace(tzinfo=timezone.utc)
        local = dt.astimezone()
        return local.strftime("%Y-%m-%d %H:%M:%S")
    except Exception:
        return iso


def _format_duration(seconds: float | int | None) -> str:
    if seconds is None or seconds < 0:
        return "—"
    seconds = int(seconds)
    h = seconds // 3600
    m = (seconds % 3600) // 60
    s = seconds % 60
    if h > 0:
        return f"{h}h {m}m {s}s"
    if m > 0:
        return f"{m}m {s}s"
    return f"{s}s"


# ---------------------------------------------------------------------------
# Template globals
# ---------------------------------------------------------------------------

def _drive_status(drive: dict) -> str:
    short = (drive.get("smart_short") or {}).get("state", "idle")
    long_ = (drive.get("smart_long") or {}).get("state", "idle")
    health = drive.get("smart_health", "UNKNOWN")
    if "running" in (short, long_):
        return "running"
    if short == "failed" or long_ == "failed" or health == "FAILED":
        return "failed"
    if "passed" in (short, long_):
        return "passed"
    return "idle"


def _format_elapsed(iso: str | None) -> str:
    """Human-readable elapsed time since an ISO timestamp (e.g. '2h 34m')."""
    if not iso:
        return ""
    try:
        start = datetime.fromisoformat(iso)
        if start.tzinfo is None:
            start = start.replace(tzinfo=timezone.utc)
        elapsed = int((datetime.now(timezone.utc) - start).total_seconds())
        if elapsed < 0:
            return ""
        h = elapsed // 3600
        m = (elapsed % 3600) // 60
        s = elapsed % 60
        if h > 0:
            return f"{h}h {m}m"
        if m > 0:
            return f"{m}m {s}s"
        return f"{s}s"
    except Exception:
        return ""


# Register filters
templates.env.filters["format_bytes"]    = _format_bytes
templates.env.filters["format_eta"]      = _format_eta
templates.env.filters["temp_class"]      = _temp_class
templates.env.filters["format_dt"]       = _format_dt
templates.env.filters["format_dt_full"]  = _format_dt_full
templates.env.filters["format_duration"] = _format_duration
templates.env.filters["format_elapsed"]  = _format_elapsed
templates.env.globals["drive_status"]    = _drive_status


from app.config import settings as _settings
templates.env.globals["app_version"] = _settings.app_version