#!/usr/bin/env python3
"""Resolve the machine-local Vivado install path.

The install path differs per machine (C:\\Xilinx here, D:\\Xilinx elsewhere), so it
is never hardcoded in a skill. It lives in ~/skills_env.md, which stays out of git.
Precedence: explicit --vivado-dir > OS env var > ~/skills_env.md.
"""
import os
import re
import sys


def env_lookup(key, default=None):
    """Read KEY from the OS environment, else from a `KEY = value` line in
    ~/skills_env.md. Trailing `# comments` are stripped."""
    v = os.environ.get(key)
    if v:
        return v
    path = os.path.join(os.path.expanduser("~"), "skills_env.md")
    try:
        with open(path, encoding="utf-8") as f:
            for line in f:
                m = re.match(rf"\s*{re.escape(key)}\s*=\s*(.+?)\s*(?:#.*)?$", line)
                if m:
                    val = m.group(1).strip()
                    # Placeholders like `<未安装>` mean "not configured on this machine".
                    if val and not val.startswith("<"):
                        return val
    except OSError:
        pass
    return default


def resolve_vivado_dir(cli_value=None):
    """Vivado install ROOT (the dir containing bin/vivado.bat)."""
    if cli_value:
        return cli_value
    root = env_lookup("VIVADO_ROOT")
    if root:
        return root
    exe = env_lookup("VIVADO_PATH")
    if exe:
        # .../<root>/bin/vivado.bat -> <root>
        return os.path.dirname(os.path.dirname(exe))
    sys.exit(
        "Vivado path not configured. Add `VIVADO_ROOT = <install root>` to "
        "~/skills_env.md, set it as an env var, or pass --vivado-dir."
    )


def resolve_vivado_exe(cli_value=None):
    """Full path to bin/vivado.bat."""
    if cli_value:
        return cli_value
    exe = env_lookup("VIVADO_PATH")
    if exe:
        return exe
    return os.path.join(resolve_vivado_dir(), "bin", "vivado.bat")


def resolve_sdk_dir(cli_value=None):
    """Xilinx SDK install ROOT (the dir containing bin/bootgen.bat).

    Precedence matches the Vivado resolver: explicit CLI value, SDK_ROOT,
    SDK_PATH, then the same keys in ~/skills_env.md.
    """
    if cli_value:
        return cli_value
    root = env_lookup("SDK_ROOT")
    if root:
        return root
    exe = env_lookup("SDK_PATH")
    if exe:
        return os.path.dirname(os.path.dirname(exe))
    sys.exit(
        "Xilinx SDK path not configured. Add `SDK_ROOT = <install root>` to "
        "~/skills_env.md, set it as an env var, or pass --sdk-dir."
    )