Add 'fiscal/' from commit '102ba84500dbd9655a0471288c3e278652593ca9'

git-subtree-dir: fiscal
git-subtree-mainline: d95165fc8f
git-subtree-split: 102ba84500

fiscal/central/app/datasets/cest.py

@@ -0,0 +1,120 @@
+"""Fail-closed parser for CONFAZ Convenio ICMS 142/18 CEST HTML."""
+
+from dataclasses import dataclass
+import hashlib
+from html.parser import HTMLParser
+import re
+
+
+_ANNEX_NUMBERS = set(range(2, 27))
+
+
+@dataclass(frozen=True)
+class CestEntry:
+    code: str
+    description: str
+    annex: str
+    ncm_codes: tuple[str, ...]
+
+
+@dataclass(frozen=True)
+class CestPayload:
+    version: str
+    sha256: str
+    entries: tuple[CestEntry, ...]
+
+
+class _TableParser(HTMLParser):
+    def __init__(self):
+        super().__init__(convert_charrefs=True)
+        self.annex = None
+        self.tables = []
+        self._table = None
+        self._row = None
+        self._cell = None
+
+    def handle_starttag(self, tag, attrs):
+        if tag == "table":
+            self._table = []
+        elif tag == "tr" and self._table is not None:
+            self._row = []
+        elif tag in {"td", "th"} and self._row is not None:
+            self._cell = []
+        elif tag == "br" and self._cell is not None:
+            self._cell.append(" ")
+
+    def handle_endtag(self, tag):
+        if tag in {"td", "th"} and self._cell is not None:
+            self._row.append("".join(self._cell).strip())
+            self._cell = None
+        elif tag == "tr" and self._row is not None:
+            self._table.append(self._row)
+            self._row = None
+        elif tag == "table" and self._table is not None:
+            self.tables.append((self.annex, self._table))
+            self._table = None
+
+    def handle_data(self, data):
+        if self._cell is not None:
+            self._cell.append(data)
+        else:
+            found = re.search(r"\bANEXO\s+([IVXLCDM]+)\b", data.upper())
+            if found:
+                self.annex = found.group(1)
+
+
+def _roman_to_number(value: str) -> int:
+    values = {"I": 1, "V": 5, "X": 10, "L": 50, "C": 100, "D": 500, "M": 1000}
+    total = 0
+    previous = 0
+    for character in reversed(value):
+        current = values[character]
+        total += -current if current < previous else current
+        previous = max(previous, current)
+    return total
+
+
+def _normalized_header(value: str) -> str:
+    return re.sub(r"[^A-Z0-9]+", "", value.upper())
+
+
+def _codes(value: str) -> tuple[str, ...]:
+    return tuple(dict.fromkeys(re.sub(r"\D", "", item) for item in re.findall(r"\b\d{2}(?:[.\s]?\d{2}){0,3}\b", value)))
+
+
+def parse_cest_html(payload: bytes) -> CestPayload:
+    try:
+        html = payload.decode("utf-8")
+    except UnicodeDecodeError as error:
+        raise ValueError("official CEST HTML must be UTF-8") from error
+    parser = _TableParser()
+    parser.feed(html)
+    entries = []
+    for annex, table in parser.tables:
+        if annex is None or _roman_to_number(annex) not in _ANNEX_NUMBERS:
+            continue
+        if not table:
+            raise ValueError("annex table is empty")
+        headers = [_normalized_header(value) for value in table[0]]
+        try:
+            cest_column = next(index for index, value in enumerate(headers) if value == "CEST")
+            ncm_column = next(index for index, value in enumerate(headers) if "NCM" in value)
+        except StopIteration as error:
+            raise ValueError("annex table is missing required columns") from error
+        description_column = next((index for index, value in enumerate(headers) if "DESCR" in value), None)
+        for row in table[1:]:
+            if len(row) <= max(cest_column, ncm_column):
+                if cest_column >= len(row) or not re.search(r"\d{2}[.\s]?\d{3}[.\s]?\d{2}", row[cest_column]):
+                    continue
+                raise ValueError("annex table row is incomplete")
+            cest = re.sub(r"\D", "", row[cest_column])
+            if not cest:
+                continue
+            ncm_codes = _codes(row[ncm_column])
+            if len(cest) != 7:
+                raise ValueError("annex table row is invalid")
+            description = row[description_column] if description_column is not None and len(row) > description_column else ""
+            entries.append(CestEntry(f"{cest[:2]}.{cest[2:5]}.{cest[5:]}", description, annex, ncm_codes))
+    if not entries:
+        raise ValueError("no CEST records found in CONFAZ annexes II-XXVI")
+    return CestPayload("CV142_18", hashlib.sha256(payload).hexdigest(), tuple(entries))