1 files changed, 154 insertions, 0 deletions
diff --git a/internal/image/gemini_api.go b/internal/image/gemini_api.go
new file mode 100644
index 0000000..f1aa1c8
--- /dev/null
+++ b/internal/image/gemini_api.go
@@ -0,0 +1,154 @@
+package image
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"google.golang.org/genai"
+
+	"codeberg.org/snonux/comicforge/internal/apicircuit"
+)
+
+func (c *GeminiProvider) generateText(ctx context.Context, model, systemPrompt, userPrompt string, temperature float32, maxOutputTokens int32) (string, error) {
+	temp := temperature
+	resp, err := apicircuit.Execute(nil, c.Name(), apicircuit.CapabilityText, func() (*genai.GenerateContentResponse, error) {
+		return c.client.Models.GenerateContent(ctx, model, []*genai.Content{
+			genai.NewContentFromText(userPrompt, genai.RoleUser),
+		}, &genai.GenerateContentConfig{
+			SystemInstruction: genai.NewContentFromText(systemPrompt, genai.RoleUser),
+			Temperature:       &temp,
+			MaxOutputTokens:   maxOutputTokens,
+		})
+	})
+	if err != nil {
+		return "", fmt.Errorf("gemini API error: %w", err)
+	}
+
+	text := strings.TrimSpace(resp.Text())
+	if text == "" {
+		return "", fmt.Errorf("no response received")
+	}
+
+	return text, nil
+}
+
+func geminiImageConfig(aspectRatio string) *genai.GenerateContentConfig {
+	if aspectRatio == "" {
+		aspectRatio = geminiAspectRatio
+	}
+
+	return &genai.GenerateContentConfig{
+		ResponseModalities: []string{string(genai.ModalityImage)},
+		ImageConfig: &genai.ImageConfig{
+			AspectRatio: aspectRatio,
+		},
+	}
+}
+
+func geminiReferenceParts(prompt string, refs [][]byte) []*genai.Part {
+	parts := make([]*genai.Part, 0, len(refs)+1)
+	for _, ref := range refs {
+		if len(ref) == 0 {
+			continue
+		}
+		parts = append(parts, &genai.Part{
+			InlineData: &genai.Blob{MIMEType: "image/png", Data: ref},
+		})
+	}
+
+	refNote := fmt.Sprintf(
+		"The %d reference image(s) above show the exact character appearance that must be preserved. "+
+			"Every character, animal, or object must look identical in the new image. Now generate:\n\n",
+		len(refs),
+	)
+	parts = append(parts, &genai.Part{Text: refNote + prompt})
+	return parts
+}
+
+func (c *GeminiProvider) generateImage(ctx context.Context, prompt, aspectRatio string) ([]byte, string, error) {
+	cfg := geminiImageConfig(aspectRatio)
+
+	resp, err := apicircuit.Execute(nil, c.Name(), apicircuit.CapabilityImage, func() (*genai.GenerateContentResponse, error) {
+		return c.client.Models.GenerateContent(ctx, c.modelName(), []*genai.Content{
+			genai.NewContentFromText(prompt, genai.RoleUser),
+		}, cfg)
+	})
+	if err != nil {
+		return nil, "", &SearchError{
+			Provider: geminiSource,
+			Code:     "API_ERROR",
+			Message:  fmt.Sprintf("failed to generate image: %v", err),
+		}
+	}
+
+	imageBytes, mimeType, err := extractGeneratedImage(resp)
+	if err != nil {
+		return nil, "", &SearchError{
+			Provider: geminiSource,
+			Code:     "NO_RESULTS",
+			Message:  err.Error(),
+		}
+	}
+
+	return imageBytes, mimeType, nil
+}
+
+func (c *GeminiProvider) generateImageWithRefs(ctx context.Context, prompt, aspectRatio string, refs [][]byte) ([]byte, string, error) {
+	cfg := geminiImageConfig(aspectRatio)
+	parts := geminiReferenceParts(prompt, refs)
+
+	resp, err := apicircuit.Execute(nil, c.Name(), apicircuit.CapabilityImage, func() (*genai.GenerateContentResponse, error) {
+		return c.client.Models.GenerateContent(ctx, c.modelName(), []*genai.Content{
+			{
+				Role:  string(genai.RoleUser),
+				Parts: parts,
+			},
+		}, cfg)
+	})
+	if err != nil {
+		return nil, "", &SearchError{
+			Provider: geminiSource,
+			Code:     "API_ERROR",
+			Message:  fmt.Sprintf("failed to generate image with refs: %v", err),
+		}
+	}
+
+	imageBytes, mimeType, err := extractGeneratedImage(resp)
+	if err != nil {
+		return nil, "", &SearchError{
+			Provider: geminiSource,
+			Code:     "NO_RESULTS",
+			Message:  err.Error(),
+		}
+	}
+
+	return imageBytes, mimeType, nil
+}
+
+func extractGeneratedImage(response *genai.GenerateContentResponse) ([]byte, string, error) {
+	if response == nil {
+		return nil, "", fmt.Errorf("no response from Gemini")
+	}
+
+	for _, candidate := range response.Candidates {
+		if candidate == nil || candidate.Content == nil {
+			continue
+		}
+
+		for _, part := range candidate.Content.Parts {
+			if part == nil || part.InlineData == nil || len(part.InlineData.Data) == 0 {
+				continue
+			}
+
+			mimeType := part.InlineData.MIMEType
+			if mimeType == "" {
+				mimeType = "image/png"
+			}
+
+			return append([]byte(nil), part.InlineData.Data...), mimeType, nil
+		}
+	}
+
+	return nil, "", fmt.Errorf("no image data returned from Gemini")
+}