good progress yay:

- impl http client
- create http client in App()
- generic builder for Service.*
- set Service on app to pass to callbacks later
- impl State
- set State on app to pass to callbacks later
- change panic to log.Fatalln

internal/http/http.go

@@ -1,6 +1,83 @@
 // http is used to interact with the home assistant
-// REST API, currently only for retrieving state for
+// REST API. Currently only used to retrieve state for
 // a single entity_id
 package http
 
-// TODO: impl http struct, should be initialized as part of App()
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+type HttpClient struct {
+	url   string
+	token string
+}
+
+func NewHttpClient(url, token string) *HttpClient {
+	url = fmt.Sprintf("http://%s/api", url)
+	return &HttpClient{url, token}
+}
+
+func (c *HttpClient) GetState(entityId string) ([]byte, error) {
+	resp, err := get(c.url+"/states/"+entityId, c.token)
+	if err != nil {
+		return nil, err
+	}
+	return resp, nil
+}
+
+func get(url, token string) ([]byte, error) {
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		return nil, errors.New("Error creating HTTP request: " + err.Error())
+	}
+
+	req.Header.Add("Authorization", "Bearer "+token)
+
+	client := &http.Client{}
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, errors.New("Error on response.\n[ERROR] -" + err.Error())
+	}
+	defer resp.Body.Close()
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, errors.New("Error while reading the response bytes:" + err.Error())
+	}
+
+	return body, nil
+}
+
+// func post(url string, token string, data any) ([]byte, error) {
+// 	postBody, err := json.Marshal(data)
+// 	if err != nil {
+// 		return nil, err
+// 	}
+// 	req, err := http.NewRequest("GET", url, bytes.NewBuffer(postBody))
+// 	if err != nil {
+// 		return nil, errors.New("Error building post request: " + err.Error())
+// 	}
+
+// 	req.Header.Add("Authorization", "Bearer "+token)
+
+// 	client := &http.Client{}
+// 	resp, err := client.Do(req)
+// 	if err != nil {
+// 		return nil, errors.New("Error in post response: " + err.Error())
+// 	}
+// 	defer resp.Body.Close()
+
+// 	if resp.StatusCode == 401 {
+// 		log.Fatalln("ERROR: Auth token is invalid. Please double check it or create a new token in your Home Assistant profile")
+// 	}
+
+// 	body, err := io.ReadAll(resp.Body)
+// 	if err != nil {
+// 		log.Fatalln(err)
+// 	}
+
+// 	return body, nil
+// }