One Interface.
Every AI Model.
Zero Data Lock-In.

// Sub-10ms Title Extraction without loading LLM
fun extractTopicTitle(firstMessage: String): String {
    val clean = firstMessage.replace(PUNCTUATION_REGEX, "")
    val keywords = clean.split(" ")
        .filter { it.length > 3 && !STOP_WORDS.contains(it.lowercase()) }
        .take(4)
        .joinToString(" ") { it.replaceFirstChar { c -> c.uppercase() } }
    return keywords.ifEmpty { "New Conversation" }
}

// Real-time parse of DeepSeek <think> reasoning tags
class StreamingThoughtParser {
    fun parseChunk(chunk: String): ParsedThoughtState {
        val thinkStart = chunk.indexOf("<think>")
        val thinkEnd = chunk.indexOf("</think>")
        
        return when {
            thinkStart != -1 && thinkEnd != -1 ->
                ParsedThoughtState.Complete(thought = chunk.substring(thinkStart + 7, thinkEnd))
            thinkStart != -1 ->
                ParsedThoughtState.Thinking(partial = chunk.substring(thinkStart + 7))
            else -> ParsedThoughtState.Output(response = chunk)
        }
    }
}

// Dual-write Markdown with YAML Frontmatter
suspend fun writeChatToObsidian(session: ChatSession, messages: List<ChatMessage>) = withContext(Dispatchers.IO) {
    val frontmatter = buildFrontmatter(session)
    val body = messages.joinToString("

") { "### ${it.sender}
${it.content}" }
    val file = File(vaultDir, "${session.id}.md")
    file.writeText("$frontmatter

$body")
}