#!/usr/bin/env python3
"""Generate Quartz's pure-Kotlin NFKC tables from the Unicode Character Database.

Usage:
    tools/unicode-nfkc/generate.py <ucd-dir> <output.kt>

<ucd-dir> must hold UnicodeData.txt and DerivedNormalizationProps.txt from
https://www.unicode.org/Public/<version>/ucd/. The version is read from the
DerivedNormalizationProps.txt header and stamped into the output.

Three tables are emitted, all as hex strings the Kotlin side parses once:
  CCC     - "start-end:ccc" ranges of non-zero canonical combining classes
  DECOMP  - "cp:x y z" full compatibility (NFKD) decompositions, already
            expanded recursively. Hangul syllables are algorithmic and omitted.
  COMPOSE - "first second composite" primary composites, i.e. two-code-point
            canonical decompositions minus Full_Composition_Exclusion.
"""

import os
import re
import sys

CHUNK = 16000  # keeps each string literal far below the JVM's 64 KB constant limit


def read_lines(path):
    with open(path, encoding="utf-8") as f:
        for line in f:
            line = line.split("#", 1)[0].strip()
            if line:
                yield line


def parse_range(text):
    if ".." in text:
        a, b = text.split("..")
        return range(int(a, 16), int(b, 16) + 1)
    return range(int(text, 16), int(text, 16) + 1)


def main(ucd_dir, out_path):
    props_path = os.path.join(ucd_dir, "DerivedNormalizationProps.txt")
    with open(props_path, encoding="utf-8") as f:
        version = re.search(r"DerivedNormalizationProps-([\d.]+)\.txt", f.readline()).group(1)

    ccc = {}
    decomp = {}  # cp -> (is_compat, [cps])
    for line in read_lines(os.path.join(ucd_dir, "UnicodeData.txt")):
        fields = line.split(";")
        cp = int(fields[0], 16)
        if int(fields[3]):
            ccc[cp] = int(fields[3])
        if fields[5]:
            parts = fields[5].split()
            compat = parts[0].startswith("<")
            if compat:
                parts = parts[1:]
            decomp[cp] = (compat, [int(p, 16) for p in parts])

    exclusions = set()
    for line in read_lines(props_path):
        fields = [x.strip() for x in line.split(";")]
        if fields[1] == "Full_Composition_Exclusion":
            exclusions.update(parse_range(fields[0]))

    def expand(cp):
        if cp not in decomp:
            return [cp]
        out = []
        for c in decomp[cp][1]:
            out.extend(expand(c))
        return out

    ccc_ranges = []
    for cp in sorted(ccc):
        last = ccc_ranges[-1] if ccc_ranges else None
        if last and last[1] == cp - 1 and last[2] == ccc[cp]:
            last[1] = cp
        else:
            ccc_ranges.append([cp, cp, ccc[cp]])

    ccc_entries = ["%X-%X:%X" % (a, b, c) for a, b, c in ccc_ranges]
    decomp_entries = [
        "%X:%s" % (cp, " ".join("%X" % c for c in expand(cp))) for cp in sorted(decomp)
    ]
    compose_entries = [
        "%X %X %X" % (parts[0], parts[1], cp)
        for cp, (compat, parts) in sorted(decomp.items())
        if not compat and len(parts) == 2 and cp not in exclusions
    ]

    def chunks(entries):
        out, cur = [], ""
        for e in entries:
            if cur and len(cur) + len(e) + 1 > CHUNK:
                out.append(cur)
                cur = ""
            cur = e if not cur else cur + ";" + e
        if cur:
            out.append(cur)
        return out

    def kotlin_array(name, entries):
        body = "".join('            "%s",\n' % c for c in chunks(entries))
        return "    val %s =\n        arrayOf(\n%s        )\n" % (name, body)

    header_path = os.path.join(os.path.dirname(os.path.abspath(__file__)), "..", "..", "quartz", "src",
                               "commonMain", "kotlin", "com", "vitorpamplona", "quartz", "utils",
                               "UnicodeNormalizer.kt")
    with open(header_path, encoding="utf-8") as f:
        license_header = f.read().split("package ", 1)[0]

    with open(out_path, "w", encoding="utf-8") as out:
        out.write(license_header)
        out.write("package com.vitorpamplona.quartz.utils.unicode\n\n")
        out.write("// GENERATED by tools/unicode-nfkc/generate.py from the Unicode %s Character Database.\n" % version)
        out.write("// Do not edit by hand; re-run the script to update.\n")
        out.write("//\n")
        out.write("// Derived from Unicode data files, Copyright (c) 1991-2025 Unicode, Inc.,\n")
        out.write("// distributed under the Unicode License v3: https://www.unicode.org/license.txt\n")
        out.write("internal object NfkcData {\n")
        out.write('    const val UNICODE_VERSION = "%s"\n\n' % version)
        out.write(kotlin_array("CCC", ccc_entries))
        out.write("\n")
        out.write(kotlin_array("DECOMP", decomp_entries))
        out.write("\n")
        out.write(kotlin_array("COMPOSE", compose_entries))
        out.write("}\n")

    print("Unicode %s: %d ccc ranges, %d decompositions, %d compositions"
          % (version, len(ccc_ranges), len(decomp_entries), len(compose_entries)))


if __name__ == "__main__":
    if len(sys.argv) != 3:
        sys.exit(__doc__)
    main(sys.argv[1], sys.argv[2])