"""N-PORT schedule-of-investments parsing for the Fund Lab page.

The raw SOI HTML files live in ``nport_cache/<sym>.html`` (one per fund,
fetched from EDGAR; see ``nport_manifest.json`` for the source URL and
filing date of each). ``build()`` parses them into a compact JSON snapshot
(``nport_cache/<sym>.json``) that the Streamlit page renders.

Parsing is deliberately conservative: each fund family formats its SOI
differently (tables, div layouts, combined multi-fund files), so we work
on a whitespace-normalized text *stream* and extract what is reliably
present:

* the fund's own category/percentage lines (the fund's reported
  composition — the star of the report),
* the as-of date and net assets,
* position rows carrying a dollar value (where the layout allows),
* a coarse keyword bucketing of those positions.

Anything we cannot parse is simply absent from the snapshot — the page
shows what we have and flags the rest.
"""

from __future__ import annotations

import bisect
import html as _html
import json
import re
from pathlib import Path

CACHE = Path(__file__).parent / "nport_cache"
MANIFEST = Path(__file__).parent / "nport_manifest.json"

_MONTHS = ("January|February|March|April|May|June|July|August|September|"
           "October|November|December")

# "<Fund name> ... Schedule of Investments" (variants)
_SECTION = re.compile(
    r"(?:CONSOLIDATED\s+)?(?:SCHEDULE\s+OF\s+(?:PORTFOLIO\s+)?INVESTMENTS|"
    r"PORTFOLIO\s+OF\s+INVESTMENTS)",
    re.I)

# category: "NAME — 12.3%" / "NAME (12.3%)" / "NAME: 12.3%" / "NAME 12.3%"
# name: starts uppercase, letters and a few punctuation marks, 3..45 chars
# (the cap keeps merged table rows from spanning a whole line).
_CAT = re.compile(
    r"(?<![A-Za-z0-9$])([A-Z][A-Za-z][A-Za-z0-9 ,/&'().\-]{1,43}?)"
    r"\s*(?:[-–—:]|\(| )\s*(\d{1,3}\s?\.\d{1,2})\s*%")


def _trim_name(name: str) -> str:
    """Strip a mixed-case prefix (table header run-on) when the tail is an
    all-caps category name: 'Maturity Fair Value CORPORATE BONDS' ->
    'CORPORATE BONDS'. Title-case names are kept whole."""
    parts = re.split(r"(?<=[a-z0-9\)-])\s+(?=[A-Z])", name)
    if len(parts) > 1:
        tail = parts[-1]
        if tail.replace(" ", "").isupper() and len(tail) >= 4:
            return tail
    return name

_DOLLAR = re.compile(r"\$\s?(\d{1,3}(?:,\d{3})*(?:\.\d+)?|\d{2,}(?:\.\d+)?)")
# a line ending in a (comma-grouped) number: position value without "$"
_TRAILNUM = re.compile(r"([\d,]{4,}(?:\.\d+)?)\s*$")

_ASOF_LONG = re.compile(rf"\b((?:{_MONTHS}) \d{{1,2}}, \d{{4}})\b")
_ASOF_SHORT = re.compile(r"\b(\d{1,2}\.\d{1,2}\.\d{2,4})\b")

_NET = re.compile(r"net assets", re.I)


def rows(html: str) -> list[str]:
    """Row-aware HTML -> list of non-empty text lines (one per table row
    / block). Div-wrapped words in some filings stay on separate rows;
    that is why most parsing is done on the joined *stream* instead."""
    x = re.sub(r"(?i)</(tr|p|div|li|h[1-6])>|<br\s*/?>", "\n", html)
    x = re.sub(r"<[^>]+>", " ", x)
    x = _html.unescape(x).replace("\xa0", " ").replace("\r", " ")
    out = []
    for ln in x.split("\n"):
        ln = re.sub(r"[ \t]+", " ", ln).strip()
        if ln:
            out.append(ln)
    return out


def find_section(text: str, tokens: list[str]) -> tuple[int, int] | None:
    """Locate the fund's own SOI section (possibly in a multi-fund file).

    ``tokens`` are case-insensitive words that must appear in the section
    header (a window around the "Schedule of Investments" phrase, which
    contains or follows the fund name). The section extends over all
    subsequent headers of the SAME fund (page-continuation footers) and
    ends at the first header that no longer names all of the fund's
    tokens.
    """
    hits = list(_SECTION.finditer(text))
    if not hits:
        return None

    def score(m: re.Match) -> int:
        near = text[max(0, m.start() - 60): m.start()].lower()
        before = text[max(0, m.start() - 150): m.start()].lower()
        after = text[m.end(): m.end() + 80].lower()
        s = sum(3 for t in tokens if t in near)
        s += sum(1 for t in tokens
                 if t not in near and (t in before or t in after))
        return s

    def names_fund(m: re.Match) -> bool:
        window = (text[max(0, m.start() - 150): m.start()]
                  + text[m.end(): m.end() + 80]).lower()
        return all(t in window for t in tokens)

    best = None
    for i, m in enumerate(hits):
        s = score(m)
        if s and (best is None or s > best[0]):
            best = (s, i)
    if best is None:
        return None
    start = max(0, hits[best[1]].start() - 200)
    end = min(len(text), start + 400_000)
    for j in range(best[1] + 1, len(hits)):
        if names_fund(hits[j]):
            continue
        # cross-references never terminate, even mid-section
        before = text[max(0, hits[j].start() - 30): hits[j].start()]
        if before.strip().lower().endswith("see"):
            continue
        end = max(start, hits[j].start() - 150)
        break
    return start, end


def _to_float(s: str) -> float:
    try:
        return float(s.replace(",", ""))
    except ValueError:
        return 0.0


def parse_section(stream: str, start: int, end: int, rs: list[str],
                  row_starts: list[int]) -> dict:
    seg = stream[start:end]
    # the rows that fall inside the section (plus the partial first row,
    # which may carry the section header)
    i1 = bisect.bisect_right(row_starts, end)
    i0 = bisect.bisect_left(row_starts, start)
    if i0 and row_starts[i0] > start:
        i0 -= 1
    lines = [ln for ln in rs[i0:i1] if ln.strip()]

    as_of = None
    head = seg[:1500]
    m = _ASOF_LONG.search(head) or _ASOF_SHORT.search(head)
    if m:
        as_of = m.group(1)

    # -- categories (global, in order of appearance, deduplicated)
    categories: list[dict] = []
    seen: set[str] = set()
    pos = 0
    while len(categories) < 60:
        cm = _CAT.search(seg, pos)
        if cm is None:
            break
        name = _trim_name(cm.group(1).strip(" -–—:("))
        # reject table-run-on junk: digits inside a category name (bond
        # series, dates, page refs), stray cell markers ("a a a"), or
        # column headers absorbed into the name. On a reject, resume from
        # just after the name start so a clean match inside the same
        # run-on is still found.
        if (re.search(r"\d", name)
                or re.search(r"\ba\s+a\b", name, re.I)
                or re.search(r"\b(shares value|value shares|security shares|"
                             r"principal amount|fair value)\b", name, re.I)):
            pos = cm.start(1) + 1
            continue
        key = name.lower()
        if key not in seen:
            seen.add(key)
            categories.append({"name": name,
                               "pct": float(cm.group(2).replace(" ", ""))})
        pos = cm.end()
    # drop total/net-asset summary lines from the list
    categories = [c for c in categories
                  if not re.match(r"^(total\s+)?(net\s+assets|investments)$",
                                  c["name"], re.I)]

    # -- positions: rows with a dollar value (last $ on the row) or,
    #    failing that, a trailing grouped number
    positions: list[dict] = []
    current_cat = ""
    for ln in lines:
        cm = _CAT.search(ln)
        if cm and not _DOLLAR.search(ln):
            current_cat = cm.group(1).strip()
        dollars = _DOLLAR.findall(ln)
        value = None
        if dollars:
            value = _to_float(dollars[-1])
        elif _TRAILNUM.search(ln):
            value = _to_float(_TRAILNUM.search(ln).group(1))
        if value is None or value <= 0:
            continue
        if _NET.search(ln) or len(ln) < 8:
            continue
        if re.fullmatch(r"[\d,$.()\s]+", ln):   # a bare number row
            continue
        positions.append({"text": re.sub(r"\s+", " ", ln)[:160],
                          "value": value, "cat": current_cat})

    # -- net assets: last "net assets" mention with a nearby number
    net_assets = None
    for nm in list(_NET.finditer(seg))[-3:]:
        window = seg[nm.end(): nm.end() + 120]
        dm = _DOLLAR.search(window) or re.search(r"([\d,]{8,}(?:\.\d+)?)", window)
        if dm:
            net_assets = _to_float(dm.group(1))
            break
    return {"as_of": as_of, "categories": categories,
            "positions": positions, "net_assets": net_assets}


# ------------------------------------------------------------------ buckets
_B_RE = [
    ("Futures",            r"\b(futur|forward|swap)\b|\bOPEN (CURRENCY|FUTURES)\b|\bCURRENCY (EXCHANGE|FORWARD|OPTION)\b"),
    ("Commodities",        r"\b(gold|silver|copper|crude|natural gas|oil|energy|agricultur|commodit|palladium|platinum|wheat|corn)\b"),
    ("Fund holdings",      r"\b(fund|etf)\b, ?class |class [a-z0-9]{1,2}\b|\bexchange[- ]trad(?:ed)? (fund|funds|etf)|\b(open[- ]end|closed[- ]end) fund|\bmoney market fund\b|\bETF\b|\bFund\b(?!s of Investments)"),
    ("Agency MBS",         r"\bmortgage\b|\bgnma\b|\bfhlmc\b|\bfnma\b|\bagency\b|\bmbs\b"),
    ("CMBS / ABS",         r"\bcmo\b|commercial mortgage|collateralized mortgage|abs (?:trust|securitization)|asset[- ]?backed"),
    ("High yield",         r"high[- ]?yield"),
    ("US govt",            r"treasur|us govt|u\.s\. government|t-bill"),
    ("IG credit / munis",  r"corporate|sovereign|senior note|notes,|bonds,|munici|nonconvertible"),
    ("Cash & T-bills",     r"^\s*cash\b|cash item|bank deposit|money market"),
    ("Equity (intl)",      r"\b(foreign|non-?us|international|emerging|europe|japan|canada|\buk\b|german|french|austral|brazil|india|china|korea|switz|netherland|spain|italy)\b"),
    ("Equity (US)",        r"\b(inc|corp|corporation|ltd|plc|group|llc|lp)\.?|common stock|equity|stock"),
]
_BUCKETS = [(name, re.compile(rx, re.I)) for name, rx in _B_RE]


def classify(text: str, category: str) -> str:
    """Keyword-bucket one position. Order matters: first match wins."""
    ctx = f"{category} | {text}"
    for name, rx in _BUCKETS:
        if rx.search(ctx):
            return name
    return "Other"


def build(sym: str, fund_tokens: list[str], force: bool = False) -> dict | None:
    """Parse the cached SOI for ``sym``; returns the snapshot (or None).

    ``fund_tokens`` identifies this fund's section inside multi-fund
    family files (e.g. ["mortgage", "opportunities"]).
    """
    html_path = CACHE / f"{sym}.html"
    json_path = CACHE / f"{sym}.json"
    if not force and json_path.exists():
        try:
            return json.loads(json_path.read_text())
        except Exception:
            pass
    if not html_path.exists():
        return None
    rs = rows(html_path.read_text())
    stream = " ".join(rs)
    row_starts: list[int] = []
    pos = 0
    for r in rs:
        row_starts.append(pos)
        pos += len(r) + 1
    sec = find_section(stream, fund_tokens)
    if sec is None:
        return None
    seg = parse_section(stream, *sec, rs, row_starts)
    buckets: dict[str, float] = {}
    for p in seg["positions"]:
        b = classify(p["text"], p["cat"])
        buckets[b] = buckets.get(b, 0.0) + p["value"]
    total = sum(buckets.values()) or 1.0
    snap = {
        "sym": sym,
        "as_of": seg["as_of"],
        "net_assets": seg["net_assets"],
        "n_positions": len(seg["positions"]),
        "categories": seg["categories"],
        "buckets": [{"name": k, "value": v, "pct": 100.0 * v / total}
                    for k, v in sorted(buckets.items(), key=lambda kv: -kv[1])],
        "top": sorted(seg["positions"], key=lambda p: -p["value"])[:40],
    }
    json_path.write_text(json.dumps(snap, indent=1))
    return snap


# ------------------------------------------------------------------ CLI
# fund-identifying tokens per ticker (used to find the fund's section in
# multi-fund family filings)
FUND_TOKENS = {
    # atesx: no cached SOI (its family's current filings don't cover it);
    # it still shows in the list with the manifest's note
    "atesx": ["anchor", "risk", "equity"],
    "atrfx": ["catalyst", "systematic"],
    "cvsix": ["calamos", "market"],
    "jlpsx": ["large cap core plus"],
    "pmaix": ["victory", "pioneer"],
    "pmfkx": ["victory", "pioneer"],
    "pmorx": ["mortgage", "opportunities"],
    "qspnx": ["style", "premia"],
    "svarx": ["spectrum low volatility"],
    "cosix": ["columbia strategic income"],
    "mbxix": ["millburn", "hedge"],
    "eagmx": ["global macro absolute return"],
    "egrsx": ["global macro absolute return"],
    "lcorx": ["leuthold core"],
    "lcrix": ["leuthold core"],
    "lamhx": ["dividend growth"],
}


def build_all(force: bool = False) -> dict:
    """Build/return snapshots for every fund with a cached SOI file."""
    out = {}
    for sym, tk in FUND_TOKENS.items():
        s = build(sym, tk, force=force)
        if s:
            out[sym] = s
    return out


def manifest() -> dict:
    return json.loads(MANIFEST.read_text())


if __name__ == "__main__":
    import sys
    syms = sys.argv[1:] or list(FUND_TOKENS)
    for s in syms:
        r = build(s, FUND_TOKENS[s], force=True)
        print(s, "->", "ok" if r else "FAILED")