package api

import (
	"io"
	"io/ioutil"
	"net/http"
	"os"

	"github.com/AlexxIT/go2rtc/cmd/app"
	"gopkg.in/yaml.v3"
)

func configHandler(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case "GET":
		data, err := os.ReadFile(app.ConfigPath)
		if err != nil {
			http.NotFound(w, r)
			return
		}
		if _, err = w.Write(data); err != nil {
			log.Warn().Err(err).Caller().Send()
		}

	case "POST":
		data, err := io.ReadAll(r.Body)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		// validate config
		var tmp struct{}
		if err = yaml.Unmarshal(data, &tmp); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		if err = os.WriteFile(app.ConfigPath, data, 0644); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	case "PATCH":
		rawdata, err := io.ReadAll(r.Body)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		data, err := mergeYAML(app.ConfigPath, rawdata)
		if err != nil {
			http.Error(w, err.Error(), http.StatusBadRequest)
			return
		}

		// validate config
		var tmp struct{}
		if err = yaml.Unmarshal(data, &tmp); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		if err = os.WriteFile(app.ConfigPath, data, 0644); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	}
}

func mergeYAML(file1 string, yaml2 []byte) ([]byte, error) {
	// Read the contents of the first YAML file
	data1, err := ioutil.ReadFile(file1)
	if err != nil {
		return nil, err
	}
	// Unmarshal the first YAML file into a map
	var config1 map[string]interface{}
	err = yaml.Unmarshal(data1, &config1)
	if err != nil {
		return nil, err
	}
	// Unmarshal the second YAML document into a map
	var config2 map[string]interface{}
	err = yaml.Unmarshal(yaml2, &config2)
	if err != nil {
		return nil, err
	}
	// Merge the two maps
	config1 = merge(config1, config2)
	// Marshal the merged map into YAML
	return yaml.Marshal(&config1)
}

func merge(a, b map[string]interface{}) map[string]interface{} {
	for k, v := range b {
		if vv, ok := a[k]; ok {
			switch vv := vv.(type) {
			case map[string]interface{}:
				v := v.(map[string]interface{})
				a[k] = merge(vv, v)
			case []interface{}:
				v := v.([]interface{})
				a[k] = v
			default:
				a[k] = v
			}
		} else {
			a[k] = v
		}
	}
	return a
}