1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
|
package tts
import (
"context"
"fmt"
"os"
"strings"
"google.golang.org/genai"
"codeberg.org/snonux/comicforge/internal/provider"
)
const (
// DefaultModel is the Gemini TTS model used for narration.
DefaultModel = "gemini-2.5-flash-preview-tts"
)
// GeminiConfig configures the Gemini TTS provider.
type GeminiConfig struct {
APIKey string
Model string
Voice string
}
// GeminiProvider generates MP3 audio with Gemini TTS.
type GeminiProvider struct {
client *genai.Client
model string
voice string
err error
}
var _ provider.TTSProvider = (*GeminiProvider)(nil)
// NewGeminiProvider creates a Gemini TTS provider.
func NewGeminiProvider(cfg *GeminiConfig) *GeminiProvider {
g := &GeminiProvider{model: DefaultModel}
if cfg == nil {
g.err = fmt.Errorf("tts config is required")
return g
}
g.model = defaultOr(cfg.Model, DefaultModel)
g.voice = cfg.Voice
if strings.TrimSpace(cfg.APIKey) == "" {
g.err = fmt.Errorf("google API key is required for TTS")
return g
}
client, err := genai.NewClient(context.Background(), &genai.ClientConfig{
APIKey: cfg.APIKey,
Backend: genai.BackendGeminiAPI,
})
if err != nil {
g.err = fmt.Errorf("create Gemini client: %w", err)
return g
}
g.client = client
return g
}
// Name returns the provider name.
func (g *GeminiProvider) Name() string { return "gemini" }
// IsAvailable reports whether the provider was initialized successfully.
func (g *GeminiProvider) IsAvailable() error {
if g == nil {
return fmt.Errorf("tts provider is nil")
}
return g.err
}
// GenerateAudio writes MP3 audio for the provided text to outputFile.
func (g *GeminiProvider) GenerateAudio(ctx context.Context, text, outputFile string) error {
if g == nil {
return fmt.Errorf("tts provider is nil")
}
if ctx == nil {
ctx = context.Background()
}
if g.err != nil {
return g.err
}
if strings.TrimSpace(text) == "" {
return fmt.Errorf("text is required")
}
if strings.TrimSpace(outputFile) == "" {
return fmt.Errorf("output file is required")
}
voiceName := g.voice
if strings.TrimSpace(voiceName) == "" {
voiceName = "Aoede"
}
speechCfg := &genai.SpeechConfig{
VoiceConfig: &genai.VoiceConfig{
PrebuiltVoiceConfig: &genai.PrebuiltVoiceConfig{VoiceName: voiceName},
},
LanguageCode: "bg-BG",
}
resp, err := g.client.Models.GenerateContent(ctx, g.model, genai.Text(text), &genai.GenerateContentConfig{
ResponseModalities: []string{"AUDIO"},
SpeechConfig: speechCfg,
})
if err != nil {
return fmt.Errorf("generate audio: %w", err)
}
data, mimeType, err := extractAudio(resp)
if err != nil {
return err
}
if strings.TrimSpace(outputFile) == "" {
return fmt.Errorf("output file is required")
}
if err := os.WriteFile(outputFile, data, 0o644); err != nil {
return fmt.Errorf("write audio: %w", err)
}
if mimeType != "" && !strings.HasPrefix(mimeType, "audio/") {
return fmt.Errorf("unexpected audio mime type %q", mimeType)
}
return nil
}
func extractAudio(resp *genai.GenerateContentResponse) ([]byte, string, error) {
if resp == nil || len(resp.Candidates) == 0 || resp.Candidates[0] == nil || resp.Candidates[0].Content == nil {
return nil, "", fmt.Errorf("no audio returned")
}
for _, part := range resp.Candidates[0].Content.Parts {
if part != nil && part.InlineData != nil && len(part.InlineData.Data) > 0 {
return part.InlineData.Data, part.InlineData.MIMEType, nil
}
}
return nil, "", fmt.Errorf("audio payload missing")
}
func defaultOr(value, fallback string) string {
if strings.TrimSpace(value) != "" {
return value
}
return fallback
}
|
