From d5cf81a9191ba5f1dab6306adf379e43dbb6c5ca Mon Sep 17 00:00:00 2001
From: Abdussamet Kocak <abdus@abdus.dev>
Date: Tue, 11 Aug 2026 09:51:30 +0200
Subject: [PATCH] feat(chat): Support Youtube transcripts

---
 chat/index.html | 244 +++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 219 insertions(+), 25 deletions(-)

diff --git a/chat/index.html b/chat/index.html
index 03806ed..e2b60cc 100644
--- a/chat/index.html
+++ b/chat/index.html
@@ -74,6 +74,49 @@
                 overflow-y: auto;
                 padding-right: 0.5rem;
             }
+            .attachment-card {
+                max-width: 85%;
+                margin: 1rem 0;
+                padding: 0.8rem 1.2rem;
+                border: 1px solid var(--border-color);
+                border-radius: 0.8rem;
+                background: var(--bg-secondary);
+            }
+            .attachment-card__title {
+                font-weight: 700;
+            }
+            .attachment-card__meta {
+                color: var(--text-secondary);
+                font-size: 0.9em;
+            }
+            .attachment-card summary {
+                cursor: pointer;
+                margin-top: 0.5rem;
+            }
+            .attachment-card pre {
+                max-height: 14rem;
+                overflow: auto;
+                white-space: pre-wrap;
+                overflow-wrap: anywhere;
+                padding: 0.6rem;
+                background: var(--bg-code);
+                border: 1px solid var(--border-color);
+                border-radius: 0.3rem;
+            }
+            .suggested-questions {
+                display: flex;
+                flex-wrap: wrap;
+                gap: 0.5rem;
+                margin: 0.75rem 0;
+            }
+            .suggested-questions button {
+                cursor: pointer;
+                padding: 0.35rem 0.6rem;
+                color: var(--text-primary);
+                background: var(--bg-primary);
+                border: 1px solid var(--border-color);
+                border-radius: 0.3rem;
+            }
             .message {
                 padding: 0.8rem 1.2rem;
                 border-radius: 0.8rem;
@@ -308,6 +351,21 @@
             <div class="chat-container">
                 <!-- Messages -->
                 <div class="messages" x-ref="msgBox" @click="onClickMessage" @scroll="handleScroll">
+                    <section class="attachment-card" x-show="attachment">
+                        <div class="attachment-card__title">Transcript attached</div>
+                        <div class="attachment-card__meta" x-text="`${attachment?.length.toLocaleString()} characters`"></div>
+                        <details>
+                            <summary>Show transcript</summary>
+                            <pre x-text="attachment?.value"></pre>
+                        </details>
+                        <template x-if="visibleMessages.length === 0 && !isBusy">
+                            <div class="suggested-questions">
+                                <button @click="useSuggestedQuestion('What are the key points?')">Key points</button>
+                                <button @click="useSuggestedQuestion('What are the most important quotes?')">Notable quotes</button>
+                                <button @click="useSuggestedQuestion('What should I challenge or verify?')">What to verify</button>
+                            </div>
+                        </template>
+                    </section>
                     <template x-for="(msg, idx) in visibleMessages" :key="idx">
                         <div :class="msg.role === 'user' ? 'message user-message' : 'message system-message'">
                             <template x-if="msg.role === 'user'">
@@ -329,7 +387,7 @@
 
                 <!-- Textarea -->
                 <div class="prompt-wrapper">
-                    <div x-show="pendingImages.length > 0" style="display: flex; gap: 0.5rem; flex-wrap: wrap; align-items: flex-start;">
+                    <div x-show="!attachment && pendingImages.length > 0" style="display: flex; gap: 0.5rem; flex-wrap: wrap; align-items: flex-start;">
                         <template x-for="(img, i) in pendingImages" :key="img.dataUrl">
                             <div style="position: relative; display: inline-block;">
                                 <img :src="img.dataUrl" style="max-height: 72px; max-width: 120px; object-fit: cover; border-radius: 0.3rem; display: block;" />
@@ -353,7 +411,7 @@
                 <button class="submit" :class="isBusy && 'busy'" @click="isBusy ? abort() : handleSubmit()" x-text="isBusy ? 'Cancel' : 'Send'"></button>
 
                 <!-- Model Selector -->
-                <details id="model-selector">
+                <details id="model-selector" x-show="!attachment">
                     <summary x-text="'Model: ' + activeModelName"></summary>
                     <template x-for="m in models" :key="m.name">
                         <label class="model-opt__label" style="display: block">
@@ -364,7 +422,7 @@
                 </details>
 
                 <!-- History -->
-                <details id="history-panel" x-ref="historyPanel">
+                <details id="history-panel" x-ref="historyPanel" x-show="!attachment">
                     <summary>History</summary>
                     <div class="history-list">
                         <template x-if="historyItems.length === 0">
@@ -399,10 +457,60 @@
                 .replace(/^\s+/gm, "")
                 .trim();
 
+            const defaultVideoSummaryPrompt = "Summarize this video or transcript. Cover the key points, necessary context, and notable quotes. Skip promotions.";
+
+            function getTranscriptAttachment(transcript) {
+                const value = typeof transcript === "string" ? transcript.trim() : "";
+                if (value) return { kind: "text", value, length: value.length };
+                return null;
+            }
+
+            function getSystemInstruction(attachment) {
+                if (!attachment) return systemPrompt;
+
+                const attachmentRules = `
+                    You are answering questions about the attached transcript.
+                    Base your answers on that source. State when the source does not establish an answer, do not invent details, and preserve exact wording when the user asks for quotes.
+                `
+                    .replace(/^\s+/gm, "")
+                    .trim();
+
+                return `${attachmentRules}\n\nTranscript:\n${attachment.value}`;
+            }
+
+            const initialAttachment = getTranscriptAttachment(window.env.YOUTUBE_TRANSCRIPT);
+            const initialPromptText = window.env.PROMPT ? `${window.env.PROMPT}\n\n` : "";
+            const geminiCachePromises = new Map();
+
+            async function getGeminiAttachmentCache({ model, apiKey, systemInstruction, attachment }) {
+                if (!attachment) return null;
+                const key = `${model}:${attachment.kind}:${attachment.value}`;
+                if (!geminiCachePromises.has(key)) {
+                    geminiCachePromises.set(
+                        key,
+                        fetch(`https://generativelanguage.googleapis.com/v1beta/cachedContents?key=${apiKey}`, {
+                            method: "POST",
+                            headers: { "Content-Type": "application/json" },
+                            body: JSON.stringify({
+                                model: `models/${model}`,
+                                systemInstruction: { parts: [{ text: systemInstruction }] },
+                                contents: [],
+                                ttl: "3600s",
+                            }),
+                        })
+                            .then(async (response) => (response.ok ? response.json() : null))
+                            .then((cache) => cache?.name || null)
+                            .catch(() => null)
+                    );
+                }
+                return geminiCachePromises.get(key);
+            }
+
             const chatApp = () => ({
                 messages: [{ role: "system", content: systemPrompt }],
                 pendingImages: [],
-                promptText: window.env.PROMPT ? `${window.env.PROMPT}\n\n` : "",
+                attachment: initialAttachment,
+                promptText: initialPromptText,
                 activeModelName: "gemini-3.5-flash-lite",
                 historyItems: [],
                 isBusy: false,
@@ -418,8 +526,11 @@
 
                 async init() {
                     this.sessionId = +new Date();
-                    this.historyItems = loadHistory();
+                    this.historyItems = this.attachment ? [] : loadHistory();
                     setTimeout(() => this.$refs.promptInput.focus(), 0);
+                    if (this.attachment && window.env.AUTO_SUBMIT === true) {
+                        setTimeout(() => this.useSuggestedQuestion(this.promptText.trim() || defaultVideoSummaryPrompt, true), 0);
+                    }
                 },
 
                 async onClickMessage(e) {
@@ -459,6 +570,12 @@
                 getExcerpt: (msgs) => msgs.find((m) => m.role === "user")?.content.slice(0, 30) || "Empty chat",
 
                 renderMarkdown,
+                useSuggestedQuestion(question, submit = false) {
+                    if (this.isBusy) return;
+                    this.promptText = question;
+                    this.$nextTick(() => this.$refs.promptInput.focus());
+                    if (submit) this.handleSubmit();
+                },
                 async handleSubmit() {
                     const text = this.promptText.trim();
                     if ((!text && !this.pendingImages.length) || this.isBusy) return;
@@ -477,11 +594,13 @@
                     this.scrollToBottom();
 
                     try {
-                        const modelObj = this.models.find((m) => m.name === this.activeModelName);
+                        const modelObj = this.models.find((m) => m.name === (this.attachment ? "gemini-3.5-flash-lite" : this.activeModelName));
                         await modelObj.chat({
-                            model: this.activeModelName,
+                            model: modelObj.name,
                             apiKey: modelObj.key,
                             messages: this.messages,
+                            attachment: this.attachment,
+                            systemInstruction: getSystemInstruction(this.attachment),
                             signal: this.abortController.signal,
                             onContent: (chunk) => {
                                 fullResponse += chunk;
@@ -505,7 +624,7 @@
                     } finally {
                         this.isBusy = false;
                         this.abortController = null;
-                        updateSessionHistory(this.sessionId, this.messages);
+                        if (!this.attachment) updateSessionHistory(this.sessionId, this.messages);
                     }
                 },
 
@@ -514,6 +633,7 @@
                 },
 
                 handlePaste(e) {
+                    if (this.attachment) return;
                     const items = [...(e.clipboardData?.items || [])];
                     const imageItems = items.filter((item) => item.type.startsWith("image/"));
                     if (!imageItems.length) return;
@@ -533,13 +653,14 @@
                     const idx = this.messages.indexOf(msg);
                     if (idx === -1) return;
                     this.messages = this.messages.slice(0, idx);
-                    updateSessionHistory(this.sessionId, this.messages);
+                    if (!this.attachment) updateSessionHistory(this.sessionId, this.messages);
                     this.promptText = msg.content;
                     this.pendingImages = msg.images ? JSON.parse(JSON.stringify(msg.images)) : [];
                     this.$nextTick(() => this.$refs.promptInput.focus());
                 },
 
                 restoreConversation(msgs) {
+                    if (this.attachment) return;
                     this.messages = JSON.parse(JSON.stringify(msgs));
                     this.userHasScrolledUp = false;
                     this.$refs.historyPanel.removeAttribute("open");
@@ -547,6 +668,7 @@
                 },
 
                 clearHistory() {
+                    if (this.attachment) return;
                     if (!confirm("Clear all saved conversations?")) return;
                     this.historyItems = clearAllHistory();
                     this.$refs.historyPanel.removeAttribute("open");
@@ -572,15 +694,28 @@
                 return $placeholder.innerHTML;
             }
 
-            async function chatWithOpenAI({ baseUrl = "https://api.openai.com/v1", onContent, onError, messages, signal, apiKey, model, extraHeaders = {}, ...rest }) {
+            async function chatWithOpenAI({ baseUrl = "https://api.openai.com/v1", onContent, onError, messages, signal, apiKey, model, extraHeaders = {}, systemInstruction, attachment, ...rest }) {
+                const lastUserIndex = messages.map((message) => message.role).lastIndexOf("user");
+                const apiMessages = messages.map(({ role, content, images }, index) => {
+                    const textPart = {
+                        type: "text",
+                        text: content,
+                        ...(index === lastUserIndex ? { prompt_cache_breakpoint: { mode: "explicit" } } : {}),
+                    };
+                    const parts = [textPart, ...(images || []).map((img) => ({ type: "image_url", image_url: { url: img.dataUrl } }))];
+                    return role === "system" || images?.length || index === lastUserIndex ? { role, content: parts } : { role, content };
+                });
                 const response = await fetch(`${baseUrl}/chat/completions`, {
                     method: "POST",
                     headers: { "Content-Type": "application/json", Authorization: `Bearer ${apiKey}`, ...extraHeaders },
-                    body: JSON.stringify({ model, messages: messages.map(({ role, content, images }) =>
-                        images?.length
-                            ? { role, content: [{ type: "text", text: content }, ...images.map((img) => ({ type: "image_url", image_url: { url: img.dataUrl } }))] }
-                            : { role, content }
-                    ), stream: true, ...rest }),
+                    body: JSON.stringify({
+                        model,
+                        messages: apiMessages,
+                        prompt_cache_key: "chat:index:v1",
+                        prompt_cache_options: { mode: "explicit" },
+                        stream: true,
+                        ...rest,
+                    }),
                     signal,
                 });
                 if (!response.ok) {
@@ -609,25 +744,83 @@
             }
 
             async function chatWithClaude(args) {
-                return chatWithOpenAI({
-                    ...args,
-                    baseUrl: "https://api.anthropic.com/v1",
-                    extraHeaders: {
-                        "x-api-key": args.apiKey,
+                const { onContent, onError, messages, signal, apiKey, model } = args;
+                const system = messages
+                    .filter((message) => message.role === "system")
+                    .map((message) => ({ type: "text", text: message.content }))
+                    .filter((part) => part.text);
+                const conversation = messages
+                    .filter((message) => message.role !== "system")
+                    .map((message) => {
+                        const images = (message.images || []).map((image) => ({
+                            type: "image",
+                            source: { type: "base64", media_type: image.mimeType, data: image.base64 },
+                        }));
+                        return {
+                            role: message.role,
+                            content: images.length ? [{ type: "text", text: message.content }, ...images] : message.content,
+                        };
+                    });
+
+                const response = await fetch("https://api.anthropic.com/v1/messages", {
+                    method: "POST",
+                    headers: {
+                        "Content-Type": "application/json",
+                        "x-api-key": apiKey,
                         "anthropic-version": "2023-06-01",
                         "anthropic-dangerous-direct-browser-access": "true",
                     },
+                    body: JSON.stringify({
+                        model,
+                        max_tokens: 4096,
+                        system,
+                        messages: conversation,
+                        cache_control: { type: "ephemeral" },
+                        stream: true,
+                    }),
+                    signal,
                 });
+
+                if (!response.ok) {
+                    const text = await response.text();
+                    await onError?.(new Error(`Anthropic API Error ${response.status}: ${text.trim()}`));
+                    return;
+                }
+
+                const reader = response.body.getReader();
+                const decoder = new TextDecoder();
+                let buffer = "";
+                while (true) {
+                    const { done, value } = await reader.read();
+                    if (done) break;
+                    buffer += decoder.decode(value, { stream: true });
+                    const events = buffer.split("\n\n");
+                    buffer = events.pop();
+                    for (const event of events) {
+                        const data = event
+                            .split("\n")
+                            .find((line) => line.startsWith("data:"))
+                            ?.slice(5)
+                            .trim();
+                        if (!data) continue;
+                        try {
+                            const parsed = JSON.parse(data);
+                            if (parsed.type === "content_block_delta" && parsed.delta?.type === "text_delta") await onContent(parsed.delta.text);
+                        } catch (error) {}
+                    }
+                }
             }
 
-            async function chatWithGemini({ onContent, onError, messages, signal, apiKey, model, ...rest }) {
-                const contents = messages.map((msg, i, arr) => {
+            async function chatWithGemini({ onContent, onError, messages, signal, apiKey, model, systemInstruction, attachment, ...rest }) {
+                const conversation = messages.filter((msg) => msg.role !== "system");
+                const cachedContent = await getGeminiAttachmentCache({ model, apiKey, systemInstruction, attachment });
+                const contents = conversation.map((msg, i) => {
                     const role = msg.role === "assistant" ? "model" : "user";
                     let parts = [{ text: msg.content }];
 
-                    // Add YouTube URLs as file data for the final user message
-                    const isLastMessage = i === arr.length - 1;
-                    if (isLastMessage && role === "user") {
+                    // Preserve the existing ability to send a YouTube URL in a normal chat message.
+                    const isLastMessage = i === conversation.length - 1;
+                    if (!attachment && isLastMessage && role === "user") {
                         const youtubeUrlPattern = /https?:\/\/(www\.)?youtube\.com\/watch\?v=[\w-]+|https?:\/\/youtu\.be\/[\w-]+/g;
                         const youtubeUrls = msg.content.match(youtubeUrlPattern) || [];
                         const fileParts = youtubeUrls.map((url) => ({ file_data: { file_uri: url } }));
@@ -650,6 +843,7 @@
                         method: "POST",
                         headers: { "Content-Type": "application/json" },
                         body: JSON.stringify({
+                            ...(cachedContent ? { cachedContent } : systemInstruction ? { system_instruction: { parts: [{ text: systemInstruction }] } } : {}),
                             contents,
                             generationConfig: rest,
                         }),