#!/usr/bin/env python3
"""Generate the standalone Bash entry from the canonical signed installer."""

import argparse
from pathlib import Path
import re


ROOT = Path(__file__).resolve().parents[1]
HEADER = '''#!/usr/bin/env bash
# Generated by sdk/install-entry.py; edit skills/scripts/install.py instead.
# The complete body must parse before any installation command can execute.
dever_install() {
    if [[ ! -x /usr/bin/python3 ]]; then
        printf '%s\\n' 'Dever 安装需要 /usr/bin/python3 3.9 或更新版本' >&2
        return 1
    fi
    /usr/bin/python3 -I -c 'import sys; sys.exit(0 if sys.version_info >= (3, 9) else "Dever 安装需要 Python 3.9 或更新版本")' || return "$?"
    local argument help=0
    for argument in "$@"; do
        case "$argument" in -h|--help) help=1 ;; esac
    done
    local -a command=(/usr/bin/python3 -I -)
    if (( EUID != 0 && help == 0 )); then
        if [[ ! -x /usr/bin/sudo ]]; then
            printf '%s\\n' 'Dever 机器安装需要管理员权限；请安装 sudo 或由管理员执行此脚本' >&2
            return 1
        fi
        command=(/usr/bin/sudo -- "${command[@]}")
    fi
    "${command[@]}" "$@" <<'DEVER_INSTALL_PYTHON'
# Preserve the source entry guard without rewriting the installer program.
__name__ = "dever_embedded_installer"
'''
FOOTER = '''DEVER_INSTALL_PYTHON
}
dever_install "$@"
'''


def render(source, public_key):
    public_key = public_key.strip()
    if not re.fullmatch(r"[0-9a-f]{64}", public_key):
        raise ValueError("release.pub must contain one Ed25519 public key")
    if "DEVER_INSTALL_PYTHON" in source.splitlines():
        raise ValueError("installer source collides with the shell heredoc delimiter")
    compile(source, "skills/scripts/install.py", "exec")
    return HEADER + source + f"\nmain(default_key={public_key!r})\n" + FOOTER


def main():
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--check", action="store_true", help="verify the checked-in entry without writing")
    arguments = parser.parse_args()
    expected = render((ROOT / "skills/scripts/install.py").read_text(),
                      (ROOT / "skills/assets/release.pub").read_text())
    destination = ROOT / "install"
    if arguments.check:
        if not destination.is_file() or destination.read_text() != expected:
            parser.exit(1, "install is stale; run python3 sdk/install-entry.py\n")
    else:
        destination.write_text(expected)
        destination.chmod(0o755)


if __name__ == "__main__":
    main()