// Package config loads only non-sensitive RemLink YAML configuration.
package config

import (
	"errors"
	"fmt"
	"io"
	"os"

	"gopkg.in/yaml.v3"
)

func decodeStrict(path string, target any) error {
	file, err := os.Open(path)
	if err != nil {
		return fmt.Errorf("open config %q: %w", path, err)
	}
	defer file.Close()

	decoder := yaml.NewDecoder(file)
	decoder.KnownFields(true)
	if err := decoder.Decode(target); err != nil {
		if errors.Is(err, io.EOF) {
			return fmt.Errorf("config %q is empty", path)
		}
		return fmt.Errorf("decode config %q: %w", path, err)
	}

	var extra any
	if err := decoder.Decode(&extra); !errors.Is(err, io.EOF) {
		if err != nil {
			return fmt.Errorf("decode trailing YAML document in %q: %w", path, err)
		}
		return fmt.Errorf("config %q must contain exactly one YAML document", path)
	}
	return nil
}