feat(gemini-web): squash all features and fixes for gemini-web

internal/client/gemini-web/convert_ext.go

@@ -0,0 +1,141 @@
+package geminiwebapi
+
+import (
+	"encoding/json"
+	"fmt"
+	"math"
+	"regexp"
+	"strings"
+	"time"
+	"unicode/utf8"
+)
+
+var (
+	reGoogle   = regexp.MustCompile("(\\()?\\[`([^`]+?)`\\]\\(https://www\\.google\\.com/search\\?q=[^)]*\\)(\\))?")
+	reColonNum = regexp.MustCompile(`([^:]+:\d+)`)
+	reInline   = regexp.MustCompile("`(\\[[^\\]]+\\]\\([^\\)]+\\))`")
+)
+
+func unescapeGeminiText(s string) string {
+	if s == "" {
+		return s
+	}
+	s = strings.ReplaceAll(s, "&lt;", "<")
+	s = strings.ReplaceAll(s, "\\<", "<")
+	s = strings.ReplaceAll(s, "\\_", "_")
+	s = strings.ReplaceAll(s, "\\>", ">")
+	return s
+}
+
+func postProcessModelText(text string) string {
+	text = reGoogle.ReplaceAllStringFunc(text, func(m string) string {
+		subs := reGoogle.FindStringSubmatch(m)
+		if len(subs) < 4 {
+			return m
+		}
+		outerOpen := subs[1]
+		display := subs[2]
+		target := display
+		if loc := reColonNum.FindString(display); loc != "" {
+			target = loc
+		}
+		newSeg := "[`" + display + "`](" + target + ")"
+		if outerOpen != "" {
+			return "(" + newSeg + ")"
+		}
+		return newSeg
+	})
+	text = reInline.ReplaceAllString(text, "$1")
+	return text
+}
+
+func estimateTokens(s string) int {
+	if s == "" {
+		return 0
+	}
+	rc := float64(utf8.RuneCountInString(s))
+	if rc <= 0 {
+		return 0
+	}
+	est := int(math.Ceil(rc / 4.0))
+	if est < 0 {
+		return 0
+	}
+	return est
+}
+
+// ConvertOutputToGemini converts simplified ModelOutput to Gemini API-like JSON.
+// promptText is used only to estimate usage tokens to populate usage fields.
+func ConvertOutputToGemini(output *ModelOutput, modelName string, promptText string) ([]byte, error) {
+	if output == nil || len(output.Candidates) == 0 {
+		return nil, fmt.Errorf("empty output")
+	}
+
+	parts := make([]map[string]any, 0, 2)
+
+	var thoughtsText string
+	if output.Candidates[0].Thoughts != nil {
+		if t := strings.TrimSpace(*output.Candidates[0].Thoughts); t != "" {
+			thoughtsText = unescapeGeminiText(t)
+			parts = append(parts, map[string]any{
+				"text":    thoughtsText,
+				"thought": true,
+			})
+		}
+	}
+
+	visible := unescapeGeminiText(output.Candidates[0].Text)
+	finalText := postProcessModelText(visible)
+	if finalText != "" {
+		parts = append(parts, map[string]any{"text": finalText})
+	}
+
+	if imgs := output.Candidates[0].GeneratedImages; len(imgs) > 0 {
+		for _, gi := range imgs {
+			if mime, data, err := FetchGeneratedImageData(gi); err == nil && data != "" {
+				parts = append(parts, map[string]any{
+					"inlineData": map[string]any{
+						"mimeType": mime,
+						"data":     data,
+					},
+				})
+			}
+		}
+	}
+
+	promptTokens := estimateTokens(promptText)
+	completionTokens := estimateTokens(finalText)
+	thoughtsTokens := 0
+	if thoughtsText != "" {
+		thoughtsTokens = estimateTokens(thoughtsText)
+	}
+	totalTokens := promptTokens + completionTokens
+
+	now := time.Now()
+	resp := map[string]any{
+		"candidates": []any{
+			map[string]any{
+				"content": map[string]any{
+					"parts": parts,
+					"role":  "model",
+				},
+				"finishReason": "stop",
+				"index":        0,
+			},
+		},
+		"createTime":   now.Format(time.RFC3339Nano),
+		"responseId":   fmt.Sprintf("gemini-web-%d", now.UnixNano()),
+		"modelVersion": modelName,
+		"usageMetadata": map[string]any{
+			"promptTokenCount":     promptTokens,
+			"candidatesTokenCount": completionTokens,
+			"thoughtsTokenCount":   thoughtsTokens,
+			"totalTokenCount":      totalTokens,
+		},
+	}
+	b, err := json.Marshal(resp)
+	if err != nil {
+		return nil, fmt.Errorf("failed to marshal gemini response: %w", err)
+	}
+	return b, nil
+}