1 files changed, 77 insertions, 1 deletions
diff --git a/state.go b/state.go
index c3c7eab..67cb1d4 100644
--- a/state.go
+++ b/state.go
@@ -1,5 +1,81 @@
 package main
 
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+)
+
 type state struct {
-	Checks map[string]int
+	stateFile string
+	Checks    map[string]int
+}
+
+func newState(config config) (state, error) {
+	stateFile := fmt.Sprintf("%s/state.json", config.StateDir)
+	state := state{stateFile, make(map[string]int)}
+
+	if _, err := os.Stat(stateFile); err != nil {
+		return state, err
+	}
+
+	file, err := os.Open(stateFile)
+	if err != nil {
+		return state, err
+	}
+	defer file.Close()
+
+	// Read the file content
+	bytes, err := ioutil.ReadAll(file)
+	if err != nil {
+		return state, err
+	}
+
+	// Parse the JSON content
+	if err := json.Unmarshal(bytes, &state.Checks); err != nil {
+		return state, err
+	}
+
+	// Clean up obsolete state information
+	var obsolete []string
+	for name := range state.Checks {
+		if _, ok := config.Checks[name]; !ok {
+			obsolete = append(obsolete, name)
+		}
+	}
+
+	for _, name := range obsolete {
+		delete(state.Checks, name)
+		log.Printf("State of %s is obsolete (removed)", name)
+	}
+
+	return state, nil
+}
+
+func (s state) update(name string, status int) bool {
+	oldStatus, ok := s.Checks[name]
+	if !ok {
+		log.Printf("State of %s: %d (new)", name, status)
+		s.Checks[name] = status
+		return true
+	}
+
+	if oldStatus != status {
+		log.Printf("State of %s: %d -> %d (changed)", name, oldStatus, status)
+		s.Checks[name] = status
+		return true
+	}
+
+	log.Printf("State of %s: %d (unchanged)", name, status)
+	return false
+}
+
+func (s state) persist() error {
+	jsonData, err := json.Marshal(s.Checks)
+	if err != nil {
+		return err
+	}
+	return ioutil.WriteFile(s.stateFile, jsonData, os.ModePerm)
 }