#!/usr/bin/env python3
"""Generate internal/cbm/pdf/pdf_unicode.c: the Unicode facts the PDF mention
scanner needs, exactly as CPython sees them (the field test's scanner ran on
CPython's str and re).

usage: scripts/gen-pdf-unicode.py internal/cbm/pdf/pdf_unicode.c  (then clang-format -i it)
The output depends on the CPython version (its Unicode data): the committed
tables were made with CPython 3.14.6 (Unicode 16.0.0).
"""
import sys
import unicodedata

MAXCP = 0x110000


def is_surrogate(c):
    return 0xD800 <= c <= 0xDFFF


def ranges(pred):
    out = []
    start = None
    for c in range(MAXCP):
        ok = not is_surrogate(c) and pred(chr(c))
        if ok and start is None:
            start = c
        elif not ok and start is not None:
            out.append((start, c - 1))
            start = None
    if start is not None:
        out.append((start, MAXCP - 1))
    return out


def emit_ranges(f, name, rs):
    f.write("const pdf_urange_t %s[] = {\n" % name)
    for i in range(0, len(rs), 4):
        f.write("    " + " ".join("{0x%X, 0x%X}," % r for r in rs[i:i + 4]) + "\n")
    f.write("};\nconst int %s_COUNT = (int)(sizeof(%s) / sizeof(%s[0]));\n\n" % (name, name, name))


def main():
    out = sys.argv[1]
    # per-character NFKC
    nfkc = []
    seq = []
    for c in range(MAXCP):
        if is_surrogate(c):
            continue
        ch = chr(c)
        m = unicodedata.normalize("NFKC", ch)
        if m != ch:
            nfkc.append((c, len(seq), len(m)))
            seq.extend(ord(x) for x in m)
    # canonical composition pairs: a + b -> c when NFC composes them
    comp = []
    for c in range(MAXCP):
        if is_surrogate(c):
            continue
        d = unicodedata.decomposition(chr(c))
        if not d or d.startswith("<"):
            continue
        parts = [int(x, 16) for x in d.split()]
        if len(parts) != 2:
            continue
        a, b = parts
        if unicodedata.normalize("NFC", chr(a) + chr(b)) == chr(c):
            comp.append((a, b, c))
    comp.sort()
    with open(out, "w", encoding="utf-8") as f:
        f.write("/*\n * pdf_unicode.c -- Unicode %s facts for the PDF mention scanner (generated).\n"
                " *\n * The field test's scanner ran on CPython's str and re; these tables are what\n"
                " * CPython %s answers: NFKC of each code point, the canonical compositions,\n"
                " * str.isspace, the re module's \\w (str.isalnum or '_'), str.isalpha, and the\n"
                " * one-character str.isupper / str.islower / titlecase. Generated by\n"
                " * scripts/gen-pdf-unicode.py; do not edit by hand. Data of the Unicode\n"
                " * Character Database, (c) Unicode, Inc., Unicode License v3\n"
                " * (THIRD_PARTY.md).\n */\n"
                % (unicodedata.unidata_version, sys.version.split()[0]))
        f.write("#include \"pdf_unicode.h\"\n\n")
        f.write("const pdf_nfkc_t PDF_NFKC[] = {\n")
        for i in range(0, len(nfkc), 4):
            f.write("    " + " ".join("{0x%X, %d, %d}," % e for e in nfkc[i:i + 4]) + "\n")
        f.write("};\nconst int PDF_NFKC_COUNT = (int)(sizeof(PDF_NFKC) / sizeof(PDF_NFKC[0]));\n\n")
        f.write("const uint32_t PDF_NFKC_SEQ[] = {\n")
        for i in range(0, len(seq), 10):
            f.write("    " + " ".join("0x%X," % x for x in seq[i:i + 10]) + "\n")
        f.write("};\n\n")
        f.write("const pdf_ucomp_t PDF_UCOMP[] = {\n")
        for i in range(0, len(comp), 3):
            f.write("    " + " ".join("{0x%X, 0x%X, 0x%X}," % e for e in comp[i:i + 3]) + "\n")
        f.write("};\nconst int PDF_UCOMP_COUNT = (int)(sizeof(PDF_UCOMP) / sizeof(PDF_UCOMP[0]));\n\n")
        emit_ranges(f, "PDF_U_SPACE", ranges(lambda c: c.isspace()))
        emit_ranges(f, "PDF_U_WORD", ranges(lambda c: c.isalnum() or c == "_"))
        emit_ranges(f, "PDF_U_ALPHA", ranges(lambda c: c.isalpha()))
        emit_ranges(f, "PDF_U_UPPER", ranges(lambda c: c.isupper()))
        emit_ranges(f, "PDF_U_LOWER", ranges(lambda c: c.islower()))
        emit_ranges(f, "PDF_U_TITLE", ranges(lambda c: c.istitle() and not c.isupper()))
    print("nfkc", len(nfkc), "seq", len(seq), "comp", len(comp))


if __name__ == "__main__":
    main()