package app

import (
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"gitea.maximumdirect.net/eric/narratio/internal/config"
)

func resolveSessionConfigPath(flagValue string) (string, error) {
	return resolveSessionConfigPathWithCandidates(flagValue, config.DefaultSessionConfigSearchPaths)
}

func resolveSessionConfigPathWithCandidates(flagValue string, candidates []string) (string, error) {
	if explicit := strings.TrimSpace(flagValue); explicit != "" {
		return explicit, nil
	}

	ordered := make([]string, 0, len(candidates))
	for _, raw := range candidates {
		path := strings.TrimSpace(raw)
		if path == "" {
			continue
		}
		ordered = append(ordered, path)
		info, err := os.Stat(path)
		if err == nil {
			if info.IsDir() {
				continue
			}
			return filepath.Clean(path), nil
		}
		if errors.Is(err, os.ErrNotExist) {
			continue
		}
		return "", fmt.Errorf("check default session config %q: %w", path, err)
	}

	if len(ordered) == 0 {
		return "", fmt.Errorf("no session config path provided and no default locations configured")
	}
	return "", fmt.Errorf(
		"no session config path provided and no default session config found; searched: %s; pass --session to use an explicit path",
		strings.Join(ordered, ", "),
	)
}