"""Isolated opencode process runtime."""

import os
import subprocess


_ENV_ALLOW = frozenset({
    "PATH", "LANG", "LANGUAGE", "LC_ALL", "LC_CTYPE", "TZ", "TERM",
    "SSL_CERT_FILE", "SSL_CERT_DIR", "NODE_EXTRA_CA_CERTS",
    "NO_PROXY", "no_proxy",
})


def shared_home(work_root):
    home = os.path.join(work_root, ".opencode-home")
    os.makedirs(home, exist_ok=True)
    return home


def ensure_global_config(home, factory_dir, install_config):
    dst_dir = os.path.join(home, ".config", "opencode")
    os.makedirs(dst_dir, exist_ok=True)
    dst = os.path.join(dst_dir, "opencode.json")
    src = os.path.join(factory_dir, "opencode.json")
    if not os.path.isfile(src):
        return
    if not os.path.isfile(dst) or os.path.getmtime(src) > os.path.getmtime(dst):
        install_config(src, dst)


def build_env(home, rtk_dir, source_env=None):
    source = os.environ if source_env is None else source_env
    env = {key: value for key, value in source.items() if key in _ENV_ALLOW}
    env["HOME"] = home
    path = env.get("PATH", "/usr/local/bin:/usr/bin:/bin")
    env["PATH"] = (rtk_dir + os.pathsep + path) if rtk_dir else path
    env["OPENCODE_EXPERIMENTAL_LSP_TOOL"] = source.get(
        "OPENCODE_EXPERIMENTAL_LSP_TOOL", "true"
    )
    return env


def warm_opencode(
    home, model, *, opencode_bin, ensure_config, build_environment,
    runner=subprocess.run,
):
    marker = os.path.join(home, ".pragent.warmed")
    if os.path.exists(marker):
        return
    ensure_config(home)
    env = build_environment(home)
    try:
        runner(
            [opencode_bin, "run", "--pure", "--model", model, "ok"],
            cwd=home, env=env, capture_output=True, text=True,
            stdin=subprocess.DEVNULL, timeout=240,
        )
    except (subprocess.TimeoutExpired, Exception):
        pass
    try:
        open(marker, "w").close()
    except OSError:
        pass


def run_opencode(
    workdir, model, *, opencode_bin, shared_home_fn, warm_fn,
    build_environment, parse_events, prompt, timeout,
    runner=subprocess.run,
):
    home = shared_home_fn()
    warm_fn(home, model)
    env = build_environment(home)
    cmd = [
        opencode_bin, "run", "--pure", "--format", "json",
        "--agent", "pragent", "--dir", workdir, "--model", model, prompt,
    ]
    last_err = ""
    for _ in range(2):
        try:
            proc = runner(
                cmd, cwd=workdir, env=env, capture_output=True, text=True,
                stdin=subprocess.DEVNULL, timeout=timeout,
            )
        except subprocess.TimeoutExpired as exc:
            last_err = f"opencode timed out after {exc.timeout}s"
            continue
        text, usage = parse_events(proc.stdout or "")
        if text.strip():
            return text, usage
        last_err = (
            f"opencode empty text (rc={proc.returncode}); "
            f"stderr: {(proc.stderr or '')[-1500:]}"
        )
    raise RuntimeError(last_err or "opencode produced no output")