app/utils.py

import re
from litestar.response import Response
from litestar.enums import MediaType


# ── Number parsing ────────────────────────────────────────────────────────────

def parse_human_number(val: str) -> float:
    """
    Parse shorthand notation into a float.

    Supports k/m/b/t suffixes (case-insensitive), comma separators, a
    leading minus sign, and trailing '%' or 'x' so the function is safe
    to call on inputs that may come from mixed-type filter boxes.

    Examples:
        '5m'   → 5_000_000
        '100k' → 100_000
        '1.5b' → 1_500_000_000
        '-2b'  → -2_000_000_000
        '0'    → 0.0
    """
    if not val:
        return 0.0
    val = str(val).strip()
    negative = val.startswith('-')
    val = val.lower().replace(',', '').replace('x', '').replace('%', '').lstrip('-')
    parts = re.findall(r'(\d+\.?\d*)([kmbt]?)', val)
    mults = {'k': 1_000, 'm': 1_000_000, 'b': 1_000_000_000, 't': 1_000_000_000_000}
    total = sum(float(num) * mults.get(unit, 1) for num, unit in parts)
    return -total if negative else total


# ── HTMX HTML helpers ─────────────────────────────────────────────────────────

def html_response(content: str, headers: dict | None = None) -> Response:
    """Return a minimal HTML fragment response for HTMX swap targets."""
    return Response(content=content, media_type=MediaType.HTML, headers=headers or {})


def msg_fragment(text: str, color: str = "red") -> str:
    """Render a small Tailwind-styled status message paragraph."""
    return f'<p class="text-{color}-400 font-semibold text-sm">{text}</p>'


# ── Number & price formatting ─────────────────────────────────────────────────

def format_price(price: float | None) -> str:
    if price is None:
        return "N/A"
    if price >= 10_000:
        return f"${price:,.0f}"
    if price >= 1:
        return f"${price:,.2f}"
    if price >= 0.001:
        return f"${price:.4f}"
    return f"${price:.6f}"


def format_large_number(val: float | None) -> str:
    """
    Format a large USD value with a T/B/M/K suffix.

    Returns "—" for None (no data). Returns "$0" for an explicit zero
    so callers can distinguish a missing value from a zero-valued one.
    """
    if val is None:
        return "—"
    if val >= 1e12:
        return f"${val/1e12:.2f}T"
    if val >= 1e9:
        return f"${val/1e9:.2f}B"
    if val >= 1e6:
        return f"${val/1e6:.1f}M"
    if val >= 1e3:
        return f"${val/1e3:.1f}K"
    return f"${val:,.0f}"


def format_pct(val: float | None) -> str:
    if val is None:
        return "—"
    return f"{val:+.1f}%"


def color_class(val: float | None) -> str:
    if val is None:
        return "text-gray-400"
    if val > 0:
        return "text-green-400"
    if val < 0:
        return "text-red-400"
    return "text-gray-400"


def vtmr_class(vtmr: float) -> str:
    if vtmr >= 1.0:
        return "text-green-300 font-bold"
    if vtmr >= 0.5:
        return "text-yellow-400"
    return "text-gray-500"


# ── Token enrichment ──────────────────────────────────────────────────────────

def enrich_token(raw: dict, *, starred: bool = False) -> dict:
    """
    Return a display-ready shallow copy of a raw or scanner-enriched coin dict.

    The copy is intentionally shallow — callers must not mutate nested objects.
    The shared in-memory cache is never modified by this function.

    VTMR is extracted with an `is not None` guard so that a scanner-computed
    value of 0.0 is preserved rather than discarded in favour of a live
    recalculation, keeping filter and display values in sync.
    """
    t = dict(raw)

    mcap  = t.get("market_cap")   or 0.0
    vol24 = t.get("total_volume") or 0.0

    _vtmr_raw = t.get("vtmr_raw")
    vtmr = _vtmr_raw if _vtmr_raw is not None else (
        (vol24 / mcap) if mcap > 0 else 0.0
    )

    p24  = t.get("price_change_percentage_24h_in_currency")
    p7d  = t.get("price_change_percentage_7d_in_currency")
    p30d = t.get("price_change_percentage_30d_in_currency")
    p1y  = t.get("price_change_percentage_1y_in_currency")

    t.update(
        fmt_price    = format_price(t.get("current_price")),
        fmt_mcap     = format_large_number(mcap  if t.get("market_cap")   is not None else None),
        fmt_volume   = format_large_number(vol24 if t.get("total_volume") is not None else None),
        fmt_24h      = format_pct(p24),
        cls_24h      = color_class(p24),
        fmt_7d       = format_pct(p7d),
        cls_7d       = color_class(p7d),
        fmt_30d      = format_pct(p30d),
        cls_30d      = color_class(p30d),
        fmt_1y       = format_pct(p1y),
        cls_1y       = color_class(p1y),
        vtmr_raw     = vtmr,
        vtmr_display = f"{vtmr:.3f}x",
        vtmr_class   = vtmr_class(vtmr),
        starred      = starred,
    )
    return t