package promptkit_test

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"testing"
	"testing/fstest"

	"gitea.maximumdirect.net/eric/ConfigKit"
	"gitea.maximumdirect.net/eric/promptkit"
)

func TestPublicConstructionWithLocalBackendAndProgrammaticProfile(t *testing.T) {
	backendID, model := "workstation", "offline-model"
	prompt := configkit.Input{Source: configkit.Mapping("prompt", map[string]any{
		"prompts": map[string]any{"hello": map[string]any{"1": map[string]any{
			"default_profile": "offline",
			"messages":        []any{map[string]any{"role": "user", "content": "Hello"}},
			"output":          map[string]any{"format": "text", "validation_mode": "none"},
		}}},
	})}
	client := &fakeLLMClient{response: &promptkit.GenerateResponse{Content: "reply"}}
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{
			{Source: promptkit.BackendSource("local backend", map[string]promptkit.BackendConfig{
				backendID: promptkit.LocalBackend("http://localhost:8000/v1", 2),
			})},
			{Source: promptkit.ProfileSource("profile", map[string]promptkit.ProfileConfig{
				"offline": {Backend: &backendID, Model: &model},
			})},
		}}},
		Main: &prompt,
	}}, promptkit.WithLLMClient(client))
	if err != nil {
		t.Fatalf("construct engine: %v", err)
	}
	result, err := engine.Run(context.Background(), promptkit.RunRequest{PromptID: "hello"})
	if err != nil {
		t.Fatalf("run prompt: %v", err)
	}
	if result.RawOutput != "reply" || result.SelectedBackendID != backendID || result.EffectiveModelParams.Model != model {
		t.Fatalf("unexpected result: %+v", result)
	}
	if len(client.requests) != 1 || client.requests[0].Target.Endpoint != "http://localhost:8000/v1" {
		t.Fatalf("unexpected model request: %+v", client.requests)
	}
}

func TestPublicConstructionCombinesEmbeddedOperatorAndProgrammaticInputs(t *testing.T) {
	embedded, err := promptkit.FilesystemInputs("embedded defaults", fstest.MapFS{
		"config/default.yaml": &fstest.MapFile{Data: []byte(`
profiles:
  application:
    endpoint: https://example.invalid/v1
    model: default-model
prompts:
  hello:
    "1":
      default_profile: application
      messages:
        - role: user
          content: Hello
      output:
        format: text
        validation_mode: none
`)},
	}, "config")
	if err != nil {
		t.Fatalf("select embedded defaults: %v", err)
	}
	operatorDirectory := t.TempDir()
	if err := os.WriteFile(filepath.Join(operatorDirectory, "override.yaml"), []byte("profiles:\n  application:\n    model: operator-model\n"), 0o644); err != nil {
		t.Fatalf("write operator input: %v", err)
	}
	operator, err := promptkit.DirectoryInputs(operatorDirectory)
	if err != nil {
		t.Fatalf("select operator inputs: %v", err)
	}
	programmaticModel := "programmatic-model"
	programmatic := configkit.Input{Source: promptkit.ProfileSource("programmatic settings", map[string]promptkit.ProfileConfig{
		"application": {Model: &programmaticModel},
	})}
	for _, test := range []struct {
		name  string
		apply bool
		want  string
	}{
		{name: "embedded", want: "default-model"},
		{name: "operator", apply: true, want: "operator-model"},
		{name: "programmatic", apply: true, want: "programmatic-model"},
	} {
		t.Run(test.name, func(t *testing.T) {
			underlays := []configkit.Underlay{{Inputs: embedded}}
			if test.apply {
				underlays = append(underlays, configkit.Underlay{Inputs: operator})
			}
			if test.name == "programmatic" {
				underlays = append(underlays, configkit.Underlay{Inputs: []configkit.Input{programmatic}})
			}
			engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{Underlays: underlays}})
			if err != nil {
				t.Fatalf("construct engine: %v", err)
			}
			prepared, err := engine.Prepare(context.Background(), promptkit.RunRequest{PromptID: "hello"})
			if err != nil {
				t.Fatalf("prepare prompt: %v", err)
			}
			if prepared.EffectiveModelParams.Model != test.want {
				t.Fatalf("model = %q, want %q", prepared.EffectiveModelParams.Model, test.want)
			}
		})
	}
}

func TestPublicConstructionPreservesConfigKitLoadError(t *testing.T) {
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{Main: &configkit.Input{
		Source: configkit.Mapping("invalid", map[string]any{"profiles": map[string]any{"broken": map[string]any{"unknown": true}}}),
	}}})
	var loadErr *configkit.LoadError
	if engine != nil || !errors.Is(err, promptkit.ErrInvalidConfig) || !errors.As(err, &loadErr) {
		t.Fatalf("construction = (%#v, %v), want invalid config preserving LoadError", engine, err)
	}
}

func TestPublicConstructionRejectsSuppliedInvalidMainInput(t *testing.T) {
	main := configkit.Input{}
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{Main: &main}})
	if engine != nil || !errors.Is(err, promptkit.ErrInvalidConfig) {
		t.Fatalf("construction = (%#v, %v), want invalid supplied main input", engine, err)
	}
}

func TestPublicConstructionCanOverlayMaintainedBackend(t *testing.T) {
	endpoint := "http://local-openrouter.example/v1"
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{Source: promptkit.BackendSource("operator backend", map[string]promptkit.BackendConfig{
			promptkit.BackendOpenRouter: {Endpoint: &endpoint},
		})}}}},
	}})
	if err != nil {
		t.Fatalf("construct engine with backend overlay: %v", err)
	}
	inspection, err := engine.InspectProfile(context.Background(), "mistral-small-3")
	if err != nil {
		t.Fatalf("inspect catalog profile: %v", err)
	}
	if inspection.EffectiveModelParams.Endpoint != endpoint {
		t.Fatalf("effective endpoint = %q, want %q", inspection.EffectiveModelParams.Endpoint, endpoint)
	}
}

func TestPreparationRejectsAmbiguousPromptVersion(t *testing.T) {
	definition := func(content string) map[string]any {
		return map[string]any{
			"messages": []any{map[string]any{"role": "user", "content": content}},
			"output":   map[string]any{"format": "text", "validation_mode": "none"},
		}
	}
	engine, err := promptkit.NewEngine(promptkit.Config{Sources: promptkit.ConfigurationSources{
		Main: &configkit.Input{Source: configkit.Mapping("versions", map[string]any{
			"prompts": map[string]any{"hello": map[string]any{
				"1": definition("first"), "2": definition("second"),
			}},
		})},
	}})
	if err != nil {
		t.Fatalf("construct engine: %v", err)
	}
	if result, err := engine.Prepare(context.Background(), promptkit.RunRequest{PromptID: "hello"}); result != nil || !errors.Is(err, promptkit.ErrPromptLoad) {
		t.Fatalf("ambiguous preparation = (%#v, %v), want ErrPromptLoad", result, err)
	}
}