#!/usr/bin/env python3
"""Embed hypher-generated `.bin` tries into constexpr headers."""

from __future__ import annotations

import argparse
import pathlib


def _format_bytes(blob: bytes, per_line: int = 16) -> str:
    # Render the blob as a comma separated list of hex literals with consistent wrapping.
    lines = []
    for i in range(0, len(blob), per_line):
        chunk = ', '.join(f"0x{b:02X}" for b in blob[i : i + per_line])
        lines.append(f"    {chunk},")
    if not lines:
        lines.append("    0x00,")
    return '\n'.join(lines)


def _symbol_from_output(path: pathlib.Path) -> str:
    # Derive a stable C identifier from the destination header name (e.g., hyph-en.trie.h -> en).
    name = path.name
    if name.endswith('.trie.h'):
        name = name[:-7]
    if name.startswith('hyph-'):
        name = name[5:]
    name = name.replace('-', '_')
    if name.endswith('.trie'):
        name = name[:-5]
    return name


def write_header(path: pathlib.Path, blob: bytes, symbol: str) -> None:
    # Emit a constexpr header containing the raw bytes plus a SerializedHyphenationPatterns descriptor.
    path.parent.mkdir(parents=True, exist_ok=True)
    data_symbol = f"{symbol}_trie_data"
    patterns_symbol = f"{symbol}_patterns"
    bytes_literal = _format_bytes(blob)
    content = f"""#pragma once

#include <cstddef>
#include <cstdint>

#include "../SerializedHyphenationTrie.h"

// Auto-generated by generate_hyphenation_trie.py. Do not edit manually.
alignas(4) constexpr uint8_t {data_symbol}[] = {{
{bytes_literal}
}};

constexpr SerializedHyphenationPatterns {patterns_symbol} = {{
    {data_symbol},
    sizeof({data_symbol}),
}};
"""
    path.write_text(content)


def main() -> None:
    parser = argparse.ArgumentParser()
    parser.add_argument('--input', dest='inputs', action='append', required=True,
                        help='Path to a hypher-generated .bin trie')
    parser.add_argument('--output', dest='outputs', action='append', required=True,
                        help='Destination header path (hyph-*.trie.h)')
    args = parser.parse_args()

    if len(args.inputs) != len(args.outputs):
        raise SystemExit('input/output counts must match')

    for src, dst in zip(args.inputs, args.outputs):
        # Process each input/output pair independently so mixed-language refreshes work in one invocation.
        src_path = pathlib.Path(src)
        blob = src_path.read_bytes()
        out_path = pathlib.Path(dst)
        symbol = _symbol_from_output(out_path)
        write_header(out_path, blob, symbol)
        print(f'wrote {dst} ({len(blob)} bytes payload)')


if __name__ == '__main__':
    main()