package config

import (
	"fmt"
	"io"

	"go.yaml.in/yaml/v4"
)

func Load(reader io.Reader) (*Config, error) {
	cfg, err := decode(reader)
	if err != nil {
		return nil, err
	}
	if err := Validate(cfg); err != nil {
		return nil, err
	}
	return cfg, nil
}

func decode(reader io.Reader) (*Config, error) {
	decoder := yaml.NewDecoder(reader)
	decoder.KnownFields(true)

	var cfg Config
	if err := decoder.Decode(&cfg); err != nil {
		return nil, fmt.Errorf("decode configuration: %w", err)
	}
	var extra any
	if err := decoder.Decode(&extra); err != io.EOF {
		if err != nil {
			return nil, fmt.Errorf("decode trailing configuration: %w", err)
		}
		return nil, fmt.Errorf("decode configuration: multiple YAML documents are not allowed")
	}
	return &cfg, nil
}