package main

import (
	"errors"
	"fmt"
	"os"
	"strconv"
	"time"

	"github.com/mathiasbq/hyperguild/ingestion/internal/symlinkguard"
)

// startupSymlinkCheck is the hyperguild#157 tripwire at boot: a symlink in the
// brain dir would let brain readers serve a file from outside the brain, so
// the server does not start until it is removed. A directory the scan cannot
// read could hide one, so it refuses on that too. A missing brain dir (first
// boot) is the only case it lets pass.
func startupSymlinkCheck(brainDir string) error {
	r, err := symlinkguard.Scan(brainDir)
	if err != nil {
		if errors.Is(err, os.ErrNotExist) {
			return nil
		}
		return fmt.Errorf("refusing to start: cannot scan the brain dir %s (hyperguild#157): %w", brainDir, err)
	}
	if !r.Clean() {
		return fmt.Errorf("refusing to start: brain dir %s has %s (hyperguild#157); fix them first", brainDir, r)
	}
	return nil
}

// symlinkScanInterval reads BRAIN_SYMLINK_SCAN_INTERVAL (seconds), falling
// back to the default on an unset, non-numeric or non-positive value.
func symlinkScanInterval(getenv func(string) string) time.Duration {
	if s, err := strconv.Atoi(getenv("BRAIN_SYMLINK_SCAN_INTERVAL")); err == nil && s > 0 {
		return time.Duration(s) * time.Second
	}
	return symlinkguard.DefaultInterval
}