package engine

import (
	"os"

	"github.com/loyaly/behavision-agent/pkg/paths"
)

// ChildEnv is the environment the engine is launched with, wherever it is
// launched from - the desktop app and the headless agent both go through
// here, so a third caller cannot get it half right.
//
// The line that matters is BEHAVISION_DATA_DIR.
//
// The engine's paths.py knows two worlds: frozen with PyInstaller, where state
// lives under ProgramData, and a checkout, where everything sits in the repo
// root. An engine installed from source into a virtual environment is neither.
// Left to itself it resolves its state root to site-packages - writes its
// database and camera list there, and generates its API credential into a
// folder this process never reads - while this process resolves the same
// state root to ProgramData. The two halves then disagree about where
// everything lives, and every call to the engine is 401 on a stock install,
// with nothing in either log saying why. Seen twice: once on a Mac checkout
// (the app in ~/Library, the engine in the repo) and once in a clean Linux
// container running the installer.
//
// Telling the engine where THIS process keeps state makes the two agree by
// construction, however the engine was installed. paths.py honours the
// override ahead of every other rule it has.
//
// hookURL is where the engine posts detections; empty is allowed and means
// the bridge has not started, which the engine treats as "no webhook".
func ChildEnv(hookURL string) []string {
	env := append(os.Environ(),
		"BEHAVISION_DATA_DIR="+paths.StateRoot(),
	)
	if hookURL != "" {
		env = append(env, "BEHAVISION_WEBHOOK_URL="+hookURL)
	}
	return env
}