refactor(application): introduce application global state (#2072)

* start breaking up the giant channel refactor now that it's better understood - easier to merge bites

Signed-off-by: Dave Lee <dave@gray101.com>

* add concurrency and base64 back in, along with new base64 tests.

Signed-off-by: Dave Lee <dave@gray101.com>

* Automatic rename of whisper.go's Result to TranscriptResult

Signed-off-by: Dave Lee <dave@gray101.com>

* remove pkg/concurrency - significant changes coming in split 2

Signed-off-by: Dave Lee <dave@gray101.com>

* fix comments

Signed-off-by: Dave Lee <dave@gray101.com>

* add list_model service as another low-risk service to get it out of the way

Signed-off-by: Dave Lee <dave@gray101.com>

* split backend config loader into seperate file from the actual config struct. No changes yet, just reduce cognative load with smaller files of logical blocks

Signed-off-by: Dave Lee <dave@gray101.com>

* rename state.go ==> application.go

Signed-off-by: Dave Lee <dave@gray101.com>

* fix lost import?

Signed-off-by: Dave Lee <dave@gray101.com>

---------

Signed-off-by: Dave Lee <dave@gray101.com>

core/services/list_models.go

@@ -0,0 +1,72 @@
+package services
+
+import (
+	"regexp"
+
+	"github.com/go-skynet/LocalAI/core/config"
+	"github.com/go-skynet/LocalAI/core/schema"
+	"github.com/go-skynet/LocalAI/pkg/model"
+)
+
+type ListModelsService struct {
+	bcl       *config.BackendConfigLoader
+	ml        *model.ModelLoader
+	appConfig *config.ApplicationConfig
+}
+
+func NewListModelsService(ml *model.ModelLoader, bcl *config.BackendConfigLoader, appConfig *config.ApplicationConfig) *ListModelsService {
+	return &ListModelsService{
+		bcl:       bcl,
+		ml:        ml,
+		appConfig: appConfig,
+	}
+}
+
+func (lms *ListModelsService) ListModels(filter string, excludeConfigured bool) ([]schema.OpenAIModel, error) {
+
+	models, err := lms.ml.ListModels()
+	if err != nil {
+		return nil, err
+	}
+
+	var mm map[string]interface{} = map[string]interface{}{}
+
+	dataModels := []schema.OpenAIModel{}
+
+	var filterFn func(name string) bool
+
+	// If filter is not specified, do not filter the list by model name
+	if filter == "" {
+		filterFn = func(_ string) bool { return true }
+	} else {
+		// If filter _IS_ specified, we compile it to a regex which is used to create the filterFn
+		rxp, err := regexp.Compile(filter)
+		if err != nil {
+			return nil, err
+		}
+		filterFn = func(name string) bool {
+			return rxp.MatchString(name)
+		}
+	}
+
+	// Start with the known configurations
+	for _, c := range lms.bcl.GetAllBackendConfigs() {
+		if excludeConfigured {
+			mm[c.Model] = nil
+		}
+
+		if filterFn(c.Name) {
+			dataModels = append(dataModels, schema.OpenAIModel{ID: c.Name, Object: "model"})
+		}
+	}
+
+	// Then iterate through the loose files:
+	for _, m := range models {
+		// And only adds them if they shouldn't be skipped.
+		if _, exists := mm[m]; !exists && filterFn(m) {
+			dataModels = append(dataModels, schema.OpenAIModel{ID: m, Object: "model"})
+		}
+	}
+
+	return dataModels, nil
+}