Function send_openai_compatible

src-tauri/src/services/chat_service.rs:377–458

(
    base_url: &str,
    model: &str,
    api_key: Option<&str>,
    include_usage: bool,
    history: Vec<Message>,
    on_token: &Channel<String>,
    cancel_token: &CancellationToken,
)

}

async fn send_openai_compatible(
    base_url: &str,
    model: &str,
    api_key: Option<&str>,
    include_usage: bool,
    history: Vec<Message>,
    on_token: &Channel<String>,
    cancel_token: &CancellationToken,
) -> AppResult<(String, Option<TokenUsage>)> {
    let client = http_client::streaming_client()?;
    let endpoint = format!("{}/chat/completions", base_url.trim_end_matches('/'));

    let messages: Vec<Value> = history
        .iter()
        .map(|m| serde_json::json!({ "role": m.role, "content": m.content }))
        .collect();

    let mut payload = serde_json::json!({
        "model": model,
        "messages": messages,
        "temperature": 0.2,
        "presence_penalty": 0.0,
        "frequency_penalty": 0.0,
        "stream": true,
    });

    if include_usage {
        payload["stream_options"] = serde_json::json!({ "include_usage": true });
    }

    // Lazy system prompt: only inject full preview guide when user asks for visuals
    let last_user_content = history.iter().rev().find(|m| m.role == "user").map(|m| m.content.as_str()).unwrap_or("");
    let system_instructions = if needs_visual_guide(last_user_content) {
        concat!(
            "IMPORTANT: Reply using the same language as the user's latest message. If user writes Indonesian, answer in Indonesian. Never switch to another language unless the user explicitly asks you to.\n\n",
            "INTERACTIVE PREVIEW: When the user asks for a visualization, diagram, chart, interactive demo, or any visual HTML content, output it as a fenced code block with tag `html:preview`. The app renders it as a live iframe preview with a full design system pre-loaded (CSS variables, SVG color ramp classes, pre-styled form elements, light/dark mode).\n\n",
            "Design rules: flat (no gradients/shadows/glow), use CSS vars for colors (var(--color-text-primary), var(--color-background-secondary), etc). system-ui font, 2 weights (400/500), sentence case. Structure: style → content → script last.\n\n",
            "SVG diagrams: use pre-loaded classes — `.t` (14px text), `.ts` (12px), `.th` (14px bold), `.box` (neutral), `.node` (clickable), `.arr` (arrow), `.leader` (dashed). Color ramps: `class=\"c-blue\"` on `<g>` wrapping shape+text — auto light/dark. Available: c-purple, c-teal, c-coral, c-blue, c-amber, c-green, c-red, c-gray, c-pink. Max 2-3 ramps per diagram.\n\n",
            "Chart.js: wrap canvas in div with position:relative + explicit height. Load UMD from cdnjs.cloudflare.com with onload callback. Disable default legend, build custom HTML legend with 10px colored squares.\n\n",
            "Interactive: form elements pre-styled. Use sendPrompt(text) for drill-down. CDN: cdnjs.cloudflare.com, cdn.jsdelivr.net, unpkg.com, esm.sh only.\n\n",
            "Always output COMPLETE standalone HTML (DOCTYPE, html, head, body). No titles/prose inside widget — explanations go in your response text."
        )
    } else {
        concat!(
            "IMPORTANT: Reply using the same language as the user's latest message. If user writes Indonesian, answer in Indonesian. Never switch to another language unless the user explicitly asks you to.\n\n",
            "You can create interactive visualizations (charts, diagrams, widgets) by outputting a fenced code block with the language tag `html:preview`. The preview iframe has a full design system pre-loaded with CSS variables, SVG color ramp classes, and light/dark mode support. Use this when the user asks for any visual or interactive content."
        )
    };
    let payload_with_system = if let Some(arr) = payload.get("messages").and_then(Value::as_array) {
        let mut updated = arr.clone();
        updated.insert(
            0,
            serde_json::json!({
                "role": "system",
                "content": system_instructions,
            }),
        );
        let mut p = payload.clone();