package prompt

import (
	"context"
	"errors"
	"testing"

	"gitea.maximumdirect.net/eric/scriptorium/internal/domain"
)

func TestGoRenderer_Render(t *testing.T) {
	renderer := NewGoRenderer()
	ctx := context.Background()

	inputs := map[string]*domain.Artifact{
		"transcript": {Body: []byte("The quick brown fox.")},
	}
	vars := map[string]string{
		"role": "helpful assistant",
		"tone": "concise",
	}

	t.Run("rendering inline message content", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "Analyze this: {{input \"transcript\"}}"},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(res.Messages) != 1 {
			t.Fatalf("expected 1 message, got %d", len(res.Messages))
		}
		if res.Messages[0].Content != "Analyze this: The quick brown fox." {
			t.Fatalf("unexpected rendered content: %q", res.Messages[0].Content)
		}
	})

	t.Run("rendering file-backed message content loaded into prompt definition", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "From file: {{input \"transcript\"}}", ContentFile: "/tmp/user.tmpl"},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if got := res.Messages[0].Content; got != "From file: The quick brown fox." {
			t.Fatalf("unexpected file-backed render result: %q", got)
		}
	})

	t.Run("rendering system and user messages", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "system", Content: "You are a {{.role}}."},
				{Role: "user", Content: "Analyze this: {{input \"transcript\"}}"},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(res.Messages) != 2 {
			t.Fatalf("expected 2 messages, got %d", len(res.Messages))
		}
		if res.Messages[0].Role != "system" || res.Messages[1].Role != "user" {
			t.Fatalf("unexpected roles: %#v", res.Messages)
		}
	})

	t.Run("copying cache control to rendered messages", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{
					Role:    "system",
					Content: "You are concise.",
					CacheControl: &domain.CacheControl{
						Type: domain.CacheControlEphemeral,
						TTL:  "1h",
					},
				},
				{Role: "user", Content: "Analyze this: {{input \"transcript\"}}"},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(res.Messages) != 2 {
			t.Fatalf("expected 2 messages, got %d", len(res.Messages))
		}
		if res.Messages[0].CacheControl == nil {
			t.Fatal("expected rendered cache control")
		}
		if res.Messages[0].CacheControl.Type != domain.CacheControlEphemeral {
			t.Fatalf("unexpected cache control type: %q", res.Messages[0].CacheControl.Type)
		}
		if res.Messages[0].CacheControl.TTL != "1h" {
			t.Fatalf("unexpected cache control ttl: %q", res.Messages[0].CacheControl.TTL)
		}
		if res.Messages[1].CacheControl != nil {
			t.Fatalf("expected no cache control on second message, got %#v", res.Messages[1].CacheControl)
		}
	})

	t.Run("rendered cache control does not alias source template", func(t *testing.T) {
		source := &domain.CacheControl{Type: domain.CacheControlEphemeral, TTL: "1h"}
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "system", Content: "You are concise.", CacheControl: source},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if res.Messages[0].CacheControl == source {
			t.Fatal("expected rendered cache control to be cloned")
		}

		res.Messages[0].CacheControl.TTL = ""
		if source.TTL != "1h" {
			t.Fatalf("source cache control was mutated, ttl=%q", source.TTL)
		}
	})

	t.Run("accessing vars", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "system", Content: "Speak in a {{.tone}} tone."},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if res.Messages[0].Content != "Speak in a concise tone." {
			t.Fatalf("unexpected vars rendering: %q", res.Messages[0].Content)
		}
	})

	t.Run("inserting required input artifact", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "{{input \"transcript\"}}"},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if res.Messages[0].Content != "The quick brown fox." {
			t.Fatalf("unexpected required input rendering: %q", res.Messages[0].Content)
		}
	})

	t.Run("optional input absent and not referenced", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{
				{Name: "transcript", Required: true},
				{Name: "glossary", Required: false},
			},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "Transcript: {{input \"transcript\"}}"},
			},
		}

		res, err := renderer.Render(ctx, def, inputs, vars)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(res.Messages) != 1 {
			t.Fatalf("expected one rendered message, got %d", len(res.Messages))
		}
	})

	t.Run("optional input absent but referenced, expecting failure", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{
				{Name: "transcript", Required: true},
				{Name: "glossary", Required: false},
			},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "Glossary: {{input \"glossary\"}}"},
			},
		}

		_, err := renderer.Render(ctx, def, inputs, vars)
		if !errors.Is(err, ErrRenderFailure) {
			t.Fatalf("expected ErrRenderFailure, got %v", err)
		}
		if !errors.Is(err, ErrUnknownInput) {
			t.Fatalf("expected ErrUnknownInput, got %v", err)
		}
	})

	t.Run("required input missing, expecting failure", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "Analyze this: {{input \"transcript\"}}"},
			},
		}

		_, err := renderer.Render(ctx, def, map[string]*domain.Artifact{}, vars)
		if !errors.Is(err, ErrMissingRequiredInput) {
			t.Fatalf("expected ErrMissingRequiredInput, got %v", err)
		}
	})

	t.Run("invalid template syntax", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "Hello {{.unclosed"},
			},
		}

		_, err := renderer.Render(ctx, def, inputs, vars)
		if !errors.Is(err, ErrInvalidTemplate) {
			t.Fatalf("expected ErrInvalidTemplate, got %v", err)
		}
	})

	t.Run("unknown input reference", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "user", Content: "Hello {{input \"ghost\"}}"},
			},
		}

		_, err := renderer.Render(ctx, def, inputs, vars)
		if !errors.Is(err, ErrRenderFailure) {
			t.Fatalf("expected ErrRenderFailure, got %v", err)
		}
		if !errors.Is(err, ErrUnknownInput) {
			t.Fatalf("expected ErrUnknownInput, got %v", err)
		}
	})

	t.Run("empty message role", func(t *testing.T) {
		def := &domain.PromptDefinition{
			Inputs: []domain.PromptInput{{Name: "transcript", Required: true}},
			Templates: []domain.PromptMessageTemplate{
				{Role: "", Content: "Hello"},
			},
		}
		_, err := renderer.Render(ctx, def, inputs, vars)
		if !errors.Is(err, ErrInvalidMessageRole) {
			t.Fatalf("expected ErrInvalidMessageRole, got %v", err)
		}
	})
}