Refactor: Restructure project

- Add an internal folder where all the internal code lives
- Make a state.go and state_test.go for the public interface

This gives a more clear separation between functions and modules. It
also makes this a more typical Go project setup.

1 files changed, 172 insertions, 0 deletions

diff --git a/internal/discovery.go b/internal/discovery.go
new file mode 100644
index 0000000..8c0acc7
--- /dev/null
+++ b/internal/discovery.go
@@ -0,0 +1,172 @@
+package internal
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type DiscoFileError struct {
+	URL string
+	Err error
+}
+
+func (e *DiscoFileError) Error() string {
+	return fmt.Sprintf("failed obtaining disco file %s with error %v", e.URL, e.Err)
+}
+
+type DiscoSigFileError struct {
+	URL string
+	Err error
+}
+
+func (e *DiscoSigFileError) Error() string {
+	return fmt.Sprintf("failed obtaining disco signature file %s with error %v", e.URL, e.Err)
+}
+
+type DiscoVerifyError struct {
+	File    string
+	Sigfile string
+	Err     error
+}
+
+func (e *DiscoVerifyError) Error() string {
+	return fmt.Sprintf("failed verifying file %s with signature %s due to error %v", e.File, e.Sigfile, e.Err)
+}
+
+type DiscoJSONError struct {
+	Body string
+	Err  error
+}
+
+func (e *DiscoJSONError) Error() string {
+	return fmt.Sprintf("failed parsing JSON for contents %s with error %v", e.Body, e.Err)
+}
+
+type OrganizationList struct {
+	JSON      json.RawMessage `json:"organization_list"`
+	Version   uint64          `json:"v"`
+	Timestamp int64           `json:"-"`
+}
+
+type ServersList struct {
+	JSON      json.RawMessage `json:"server_list"`
+	Version   uint64          `json:"v"`
+	Timestamp int64           `json:"-"`
+}
+
+type Discovery struct {
+	Organizations OrganizationList
+	Servers       ServersList
+	FSM *FSM
+	Logger *FileLogger
+}
+
+// Helper function that gets a disco json
+func getDiscoFile(jsonFile string, previousVersion uint64, structure interface{}) error {
+	// Get json data
+	discoURL := "https://disco.eduvpn.org/v2/"
+	fileURL := discoURL + jsonFile
+	_, fileBody, fileErr := HTTPGet(fileURL)
+
+	if fileErr != nil {
+		return &DiscoFileError{fileURL, fileErr}
+	}
+
+	// Get signature
+	sigFile := jsonFile + ".minisig"
+	sigURL := discoURL + sigFile
+	_, sigBody, sigFileErr := HTTPGet(sigURL)
+
+	if sigFileErr != nil {
+		return &DiscoSigFileError{URL: sigURL, Err: sigFileErr}
+	}
+
+	// Verify signature
+	// Set this to true when we want to force prehash
+	forcePrehash := false
+	verifySuccess, verifyErr := Verify(string(sigBody), fileBody, jsonFile, previousVersion, forcePrehash)
+
+	if !verifySuccess || verifyErr != nil {
+		return &DiscoVerifyError{File: jsonFile, Sigfile: sigFile, Err: verifyErr}
+	}
+
+	// Parse JSON to extract version and list
+	jsonErr := json.Unmarshal(fileBody, structure)
+
+	if jsonErr != nil {
+		return &DiscoJSONError{Body: string(fileBody), Err: jsonErr}
+	}
+
+	return nil
+}
+
+type GetListError struct {
+	File string
+	Err  error
+}
+
+func (e *GetListError) Error() string {
+	return fmt.Sprintf("failed getting disco list file %s with error %v", e.File, e.Err)
+}
+
+func (discovery *Discovery) Init(fsm *FSM, logger *FileLogger) {
+	discovery.FSM = fsm
+	discovery.Logger = logger
+}
+
+// FIXME: Implement based on
+// https://github.com/eduvpn/documentation/blob/v3/SERVER_DISCOVERY.md
+// - [IMPLEMENTED] on "first launch" when offering the search for "Institute Access" and "Organizations";
+// - [TODO] when the user tries to add new server AND the user did NOT yet choose an organization before;
+// - [TODO] when the authorization for the server associated with an already chosen organization is triggered, e.g. after expiry or revocation.
+func (discovery *Discovery) DetermineOrganizationsUpdate() bool {
+	return string(discovery.Organizations.JSON) == ""
+}
+
+// https://github.com/eduvpn/documentation/blob/v3/SERVER_DISCOVERY.md
+// - [Implemented] The application MUST always fetch the server_list.json at application start.
+// - The application MAY refresh the server_list.json periodically, e.g. once every hour.
+func (discovery *Discovery) DetermineServersUpdate() bool {
+	// No servers, we should update
+	if string(discovery.Servers.JSON) == "" {
+		return true
+	}
+	// 1 hour from the last update
+	should_update_time := discovery.Servers.Timestamp + 3600
+	now := GenerateTimeSeconds()
+	if now >= should_update_time {
+		return true
+	}
+	discovery.Logger.Log(LOG_INFO, "No update needed for servers, 1h is not passed yet")
+	return false
+}
+
+// Get the organization list
+func (discovery *Discovery) GetOrganizationsList() (string, error) {
+	if !discovery.DetermineOrganizationsUpdate() {
+		return string(discovery.Organizations.JSON), nil
+	}
+	file := "organization_list.json"
+	err := getDiscoFile(file, discovery.Organizations.Version, &discovery.Organizations)
+	if err != nil {
+		// Return previous with an error
+		return string(discovery.Organizations.JSON), &GetListError{File: file, Err: err}
+	}
+	return string(discovery.Organizations.JSON), nil
+}
+
+// Get the server list
+func (discovery *Discovery) GetServersList() (string, error) {
+	if !discovery.DetermineServersUpdate() {
+		return string(discovery.Servers.JSON), nil
+	}
+	file := "server_list.json"
+	err := getDiscoFile(file, discovery.Servers.Version, &discovery.Servers)
+	if err != nil {
+		// Return previous with an error
+		return string(discovery.Servers.JSON), &GetListError{File: file, Err: err}
+	}
+	// Update servers timestamp
+	discovery.Servers.Timestamp = GenerateTimeSeconds()
+	return string(discovery.Servers.JSON), nil
+}