#!/usr/bin/env python3
"""Embeds web/ (the browser UI) into src/webui_assets.hpp.

Run this after editing anything in web/:   python3 tools/embed_web.py

Each file becomes a few C++ raw string literals of at most ~12 KB, because
MSVC rejects longer string literals. The generated header is checked in, so
building antlrlab does not need Python.
"""
import glob
import os
import sys

ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
WEB = os.path.join(ROOT, "web")
OUT = os.path.join(ROOT, "src", "webui_assets.hpp")
DELIM = "__WEB__"
CHUNK = 12000


def read(path):
    with open(path, encoding="utf-8") as f:
        text = f.read()
    try:
        text.encode("ascii")
    except UnicodeEncodeError as e:
        sys.exit("%s contains non-ASCII text (%s). Use \\u escapes or entities." % (path, e))
    if ")" + DELIM + '"' in text:
        sys.exit("%s contains the raw string terminator" % path)
    return text


def chunks(text):
    out, cur = [], ""
    for line in text.splitlines(keepends=True):
        if len(cur) + len(line) > CHUNK and cur:
            out.append(cur)
            cur = ""
        cur += line
    if cur:
        out.append(cur)
    return out


def function(name, text):
    body = "".join('  s += R"%s(%s)%s";\n' % (DELIM, c, DELIM) for c in chunks(text))
    return "inline std::string %s() {\n  std::string s;\n%s  return s;\n}\n" % (name, body)


def main():
    js = "".join(read(p) for p in sorted(glob.glob(os.path.join(WEB, "[0-9]*.js"))))
    parts = [
        "// GENERATED by tools/embed_web.py from web/ - do not edit by hand.\n",
        "#pragma once\n\n#include <string>\n\nnamespace lab {\n\n",
        function("webIndexHtml", read(os.path.join(WEB, "index.html"))),
        "\n",
        function("webCss", read(os.path.join(WEB, "app.css"))),
        "\n",
        function("webJs", js),
        "\n}  // namespace lab\n",
    ]
    with open(OUT, "w", encoding="utf-8", newline="\n") as f:
        f.write("".join(parts))
    print("wrote %s (%d bytes of JS, %d files)" % (OUT, len(js), len(glob.glob(os.path.join(WEB, "[0-9]*.js")))))


main()