1 files changed, 187 insertions, 0 deletions
diff --git a/internal/fsm.go b/internal/fsm.go
new file mode 100644
index 0000000..fadc7c9
--- /dev/null
+++ b/internal/fsm.go
@@ -0,0 +1,187 @@
+package internal
+
+import (
+	"fmt"
+	"os"
+	"sort"
+)
+
+type (
+	FSMStateID      int8
+	FSMStateIDSlice []FSMStateID
+)
+
+func (v FSMStateIDSlice) Len() int {
+	return len(v)
+}
+
+func (v FSMStateIDSlice) Less(i, j int) bool {
+	return v[i] < v[j]
+}
+
+func (v FSMStateIDSlice) Swap(i, j int) {
+	v[i], v[j] = v[j], v[i]
+}
+
+const (
+	// Deregistered means the app is not registered with the wrapper
+	DEREGISTERED FSMStateID = iota
+
+	// No Server means the user has not chosen a server yet
+	NO_SERVER
+
+	// Chosen Server means the user has chosen a server to connect to
+	CHOSEN_SERVER
+
+	// OAuth Started means the OAuth process has started
+	OAUTH_STARTED
+
+	// Authenticated means the OAuth process has finished and the user is now authenticated with the server
+	AUTHENTICATED
+
+	// Requested config means the user has requested a config for connecting
+	REQUEST_CONFIG
+
+	// Has config means the user has gotten a config
+	HAS_CONFIG
+
+	// Ask profile means the go code is asking for a profile selection from the ui
+	ASK_PROFILE
+
+	// Connected means the user has been connected to the server
+	CONNECTED
+)
+
+func (s FSMStateID) String() string {
+	switch s {
+	case DEREGISTERED:
+		return "Deregistered"
+	case NO_SERVER:
+		return "No_Server"
+	case CHOSEN_SERVER:
+		return "Chosen_Server"
+	case OAUTH_STARTED:
+		return "OAuth_Started"
+	case HAS_CONFIG:
+		return "Has_Config"
+	case REQUEST_CONFIG:
+		return "Request_Config"
+	case ASK_PROFILE:
+		return "Ask_Profile"
+	case AUTHENTICATED:
+		return "Authenticated"
+	case CONNECTED:
+		return "Connected"
+	default:
+		panic("unknown conversion of state to string")
+	}
+}
+
+type FSMTransition struct {
+	To          FSMStateID
+	Description string
+}
+
+type (
+	FSMTransitions []FSMTransition
+	FSMStates      map[FSMStateID]FSMTransitions
+)
+
+type FSM struct {
+	States  FSMStates
+	Current FSMStateID
+
+	// Info to be passed from the parent state
+	StateCallback func(string, string, string)
+	Logger        *FileLogger
+	Debug         bool
+}
+
+func (fsm *FSM) Init(callback func(string, string, string), logger *FileLogger, debug bool) {
+	fsm.States = FSMStates{
+		DEREGISTERED:   {{NO_SERVER, "Client registers"}},
+		NO_SERVER:      {{CHOSEN_SERVER, "User chooses a server"}},
+		CHOSEN_SERVER:  {{AUTHENTICATED, "Found tokens in config"}, {OAUTH_STARTED, "No tokens found in config"}},
+		OAUTH_STARTED:  {{AUTHENTICATED, "User authorizes with browser"}},
+		AUTHENTICATED:  {{OAUTH_STARTED, "Re-authenticate with OAuth"}, {REQUEST_CONFIG, "Client requests a config"}},
+		REQUEST_CONFIG: {{ASK_PROFILE, "Multiple profiles found"}, {HAS_CONFIG, "Success, only one profile"}},
+		ASK_PROFILE:    {{HAS_CONFIG, "User chooses profile and success"}},
+		HAS_CONFIG:     {{CONNECTED, "OS reports connected"}},
+		CONNECTED:      {{AUTHENTICATED, "OS reports disconnected"}},
+	}
+	fsm.Current = DEREGISTERED
+	fsm.StateCallback = callback
+	fsm.Logger = logger
+	fsm.Debug = debug
+}
+
+func (fsm *FSM) InState(check FSMStateID) bool {
+	return check == fsm.Current
+}
+
+func (fsm *FSM) HasTransition(check FSMStateID) bool {
+	for _, transition_state := range fsm.States[fsm.Current] {
+		if transition_state.To == check {
+			return true
+		}
+	}
+
+	return false
+}
+
+func (fsm *FSM) writeGraph() {
+	graph := fsm.GenerateGraph()
+
+	f, err := os.Create("debug.graph")
+	if err != nil {
+		fsm.Logger.Log(LOG_INFO, fmt.Sprintf("Failed to write debug fsm graph with error %v", err))
+	}
+
+	defer f.Close()
+
+	f.WriteString(graph)
+}
+
+func (fsm *FSM) GoTransitionWithData(newState FSMStateID, data string) bool {
+	ok := fsm.HasTransition(newState)
+
+	if ok {
+		oldState := fsm.Current
+		fsm.Current = newState
+		if fsm.Debug {
+			fsm.writeGraph()
+		}
+		fsm.StateCallback(oldState.String(), newState.String(), data)
+	}
+
+	return ok
+}
+
+func (fsm *FSM) GoTransition(newState FSMStateID) bool {
+	return fsm.GoTransitionWithData(newState, "")
+}
+
+func (fsm *FSM) generateMermaidGraph() string {
+	graph := "graph TD\n"
+	sorted_fsm := make(FSMStateIDSlice, 0, len(fsm.States))
+	for state_id := range fsm.States {
+		sorted_fsm = append(sorted_fsm, state_id)
+	}
+	sort.Sort(sorted_fsm)
+	for _, state := range sorted_fsm {
+		transitions := fsm.States[state]
+		for _, transition := range transitions {
+			if state == fsm.Current {
+				graph += "\nstyle " + state.String() + " fill:cyan\n"
+			} else {
+				graph += "\nstyle " + state.String() + " fill:white\n"
+			}
+			graph += state.String() + "(" + state.String() + ") " + "-->|" + transition.Description + "| " + transition.To.String() + "\n"
+		}
+	}
+	return graph
+}
+
+func (fsm *FSM) GenerateGraph() string {
+	return fsm.generateMermaidGraph()
+}