// Copyright 2025, IPng Networks GmbH, Pim van Pelt <pim@ipng.ch>

package main

import (
	"fmt"
	"io/ioutil"

	"dario.cat/mergo"
	"gopkg.in/yaml.v3"
)

// Config structures
type Config struct {
	Types   map[string]DeviceType `yaml:"types"`
	Devices map[string]Device     `yaml:"devices"`
}

type DeviceType struct {
	Commands []string `yaml:"commands"`
}

type Device struct {
	User     string   `yaml:"user"`
	Type     string   `yaml:"type,omitempty"`
	Commands []string `yaml:"commands,omitempty"`
	Address  string   `yaml:"address,omitempty"`
}

func readYAMLFile(path string) (map[string]interface{}, error) {
	data, err := ioutil.ReadFile(path)
	if err != nil {
		return nil, err
	}

	var result map[string]interface{}
	if err := yaml.Unmarshal(data, &result); err != nil {
		return nil, err
	}

	return result, nil
}

// ConfigRead loads and merges multiple YAML files into a single config object
func ConfigRead(yamlFiles []string) (*Config, error) {
	var finalConfig map[string]interface{}

	for _, file := range yamlFiles {
		current, err := readYAMLFile(file)
		if err != nil {
			return nil, fmt.Errorf("failed to parse %s: %v", file, err)
		}

		if finalConfig == nil {
			finalConfig = current
		} else {
			err := mergo.Merge(&finalConfig, current, mergo.WithOverride)
			if err != nil {
				return nil, fmt.Errorf("failed to merge %s: %v", file, err)
			}
		}
	}

	// Convert back to structured config
	out, err := yaml.Marshal(finalConfig)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal merged config: %v", err)
	}

	var config Config
	if err := yaml.Unmarshal(out, &config); err != nil {
		return nil, fmt.Errorf("failed to unmarshal to Config struct: %v", err)
	}

	return &config, nil
}