refactor: interfaces and data types into the model package (#642)

## Checklist

- [x] I have read the [contribution guidelines](https://github.com/ooni/probe-cli/blob/master/CONTRIBUTING.md)
- [x] reference issue for this pull request: https://github.com/ooni/probe/issues/1885
- [x] related ooni/spec pull request: N/A

Location of the issue tracker: https://github.com/ooni/probe

## Description

This PR contains a set of changes to move important interfaces and data types into the `./internal/model` package.

The criteria for including an interface or data type in here is roughly that the type should be important and used by several packages. We are especially interested to move more interfaces here to increase modularity.

An additional side effect is that, by reading this package, one should be able to understand more quickly how different parts of the codebase interact with each other.

This is what I want to move in `internal/model`:

- [x] most important interfaces from `internal/netxlite`
- [x] everything that was previously part of `internal/engine/model`
- [x] mocks from `internal/netxlite/mocks` should also be moved in here as a subpackage

pkg/oonimkall/experiment.go

@@ -4,7 +4,7 @@ import (
 	"context"
 
 	"github.com/ooni/probe-cli/v3/internal/engine"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 // experimentSession is the abstract representation of

pkg/oonimkall/experiment_test.go

@@ -5,7 +5,7 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 // FakeExperimentCallbacks contains fake ExperimentCallbacks.

pkg/oonimkall/session.go

@@ -11,9 +11,9 @@ import (
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
 	"github.com/ooni/probe-cli/v3/internal/engine"
 	"github.com/ooni/probe-cli/v3/internal/engine/legacy/assetsdir"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
 	"github.com/ooni/probe-cli/v3/internal/engine/probeservices"
 	"github.com/ooni/probe-cli/v3/internal/kvstore"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
 
@@ -161,9 +161,9 @@ func newSessionWithContext(ctx context.Context, config *SessionConfig) (*Session
 	// the return value as it does not matter to us here.
 	_, _ = assetsdir.Cleanup(config.AssetsDir)
 
-	var availableps []model.Service
+	var availableps []model.OOAPIService
 	if config.ProbeServicesURL != "" {
-		availableps = append(availableps, model.Service{
+		availableps = append(availableps, model.OOAPIService{
 			Address: config.ProbeServicesURL,
 			Type:    "https",
 		})
@@ -347,8 +347,8 @@ func (ckw *CheckInConfigWebConnectivity) Add(cat string) {
 	ckw.CategoryCodes = append(ckw.CategoryCodes, cat)
 }
 
-func (ckw *CheckInConfigWebConnectivity) toModel() model.CheckInConfigWebConnectivity {
-	return model.CheckInConfigWebConnectivity{
+func (ckw *CheckInConfigWebConnectivity) toModel() model.OOAPICheckInConfigWebConnectivity {
+	return model.OOAPICheckInConfigWebConnectivity{
 		CategoryCodes: ckw.CategoryCodes,
 	}
 }
@@ -386,7 +386,7 @@ type CheckInInfoWebConnectivity struct {
 	ReportID string
 
 	// URLs contains the list of URLs to measure.
-	URLs []model.URLInfo
+	URLs []model.OOAPIURLInfo
 }
 
 // URLInfo contains info on a specific URL to measure.
@@ -421,7 +421,7 @@ func (ckw *CheckInInfoWebConnectivity) At(idx int64) *URLInfo {
 	}
 }
 
-func newCheckInInfoWebConnectivity(ckw *model.CheckInInfoWebConnectivity) *CheckInInfoWebConnectivity {
+func newCheckInInfoWebConnectivity(ckw *model.OOAPICheckInInfoWebConnectivity) *CheckInInfoWebConnectivity {
 	if ckw == nil {
 		return nil
 	}
@@ -466,7 +466,7 @@ func (sess *Session) CheckIn(ctx *Context, config *CheckInConfig) (*CheckInInfo,
 	if sess.TestingCheckInBeforeCheckIn != nil {
 		sess.TestingCheckInBeforeCheckIn(ctx) // for testing
 	}
-	cfg := model.CheckInConfig{
+	cfg := model.OOAPICheckInConfig{
 		Charging:        config.Charging,
 		OnWiFi:          config.OnWiFi,
 		Platform:        config.Platform,
@@ -494,7 +494,7 @@ type URLListConfig struct {
 
 // URLListResult contains the URLs returned from the FetchURL API
 type URLListResult struct {
-	Results []model.URLInfo
+	Results []model.OOAPIURLInfo
 }
 
 // AddCategory adds category code to the array in URLListConfig
@@ -538,7 +538,7 @@ func (sess *Session) FetchURLList(ctx *Context, config *URLListConfig) (*URLList
 			config.CountryCode = info.CountryCode
 		}
 	}
-	cfg := model.URLListConfig{
+	cfg := model.OOAPIURLListConfig{
 		Categories:  config.Categories,
 		CountryCode: config.CountryCode,
 		Limit:       config.Limit,

pkg/oonimkall/session_integration_test.go

@@ -13,7 +13,7 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine/geolocate"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/pkg/oonimkall"
 )
 

pkg/oonimkall/sessionlogger.go

@@ -3,7 +3,7 @@ package oonimkall
 import (
 	"fmt"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 type loggerVerbose struct {

pkg/oonimkall/sessionlogger_test.go

@@ -8,7 +8,7 @@ import (
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 type RecordingLogger struct {

pkg/oonimkall/task_test.go

@@ -5,7 +5,7 @@ import (
 	"errors"
 	"testing"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 type eventlike struct {

pkg/oonimkall/tasklogger.go

@@ -3,7 +3,7 @@ package oonimkall
 import (
 	"fmt"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 //

pkg/oonimkall/tasklogger_test.go

@@ -3,7 +3,7 @@ package oonimkall
 import (
 	"testing"
 
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 //

pkg/oonimkall/taskmocks_test.go

@@ -6,7 +6,7 @@ import (
 	"sync"
 
 	"github.com/ooni/probe-cli/v3/internal/engine"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 //

pkg/oonimkall/taskmodel.go

@@ -5,7 +5,7 @@ import (
 	"io"
 
 	"github.com/ooni/probe-cli/v3/internal/engine"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 //

pkg/oonimkall/taskrunner.go

@@ -8,7 +8,7 @@ import (
 	"time"
 
 	"github.com/ooni/probe-cli/v3/internal/engine"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 	"github.com/ooni/probe-cli/v3/internal/runtimex"
 )
 
@@ -68,7 +68,7 @@ func (r *runnerForTask) newsession(ctx context.Context, logger model.Logger) (ta
 		TunnelDir:       r.settings.TunnelDir,
 	}
 	if r.settings.Options.ProbeServicesBaseURL != "" {
-		config.AvailableProbeServices = []model.Service{{
+		config.AvailableProbeServices = []model.OOAPIService{{
 			Type:    "https",
 			Address: r.settings.Options.ProbeServicesBaseURL,
 		}}

pkg/oonimkall/taskrunner_test.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	engine "github.com/ooni/probe-cli/v3/internal/engine"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 func TestMeasurementSubmissionEventName(t *testing.T) {

pkg/oonimkall/tasksession.go

@@ -4,8 +4,8 @@ import (
 	"context"
 
 	"github.com/ooni/probe-cli/v3/internal/engine"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
 	"github.com/ooni/probe-cli/v3/internal/kvstore"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 //

pkg/oonimkall/webconnectivity_test.go

@@ -8,7 +8,7 @@ import (
 
 	"github.com/google/go-cmp/cmp"
 	"github.com/ooni/probe-cli/v3/internal/atomicx"
-	"github.com/ooni/probe-cli/v3/internal/engine/model"
+	"github.com/ooni/probe-cli/v3/internal/model"
 )
 
 func TestWebConnectivityRunnerWithMaybeLookupBackendsFailure(t *testing.T) {