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src-tauri/src/asr.rs

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+//! Aliyun DashScope file-trans ASR client (qwen3-asr-flash-filetrans).
+//!
+//! The dashscope async transcription flow has two steps:
+//!   1. POST  https://dashscope.aliyuncs.com/api/v1/services/audio/asr/transcription
+//!      header `X-DashScope-Async: enable`
+//!      body   { model, input: { file_urls: [audio_url] }, parameters: {...} }
+//!      => returns task_id
+//!   2. GET   https://dashscope.aliyuncs.com/api/v1/tasks/{task_id}
+//!      poll until task_status in {SUCCEEDED, FAILED}
+//!
+//! On success the response carries one or more `transcription_url`s pointing
+//! at JSON files containing the recognized sentences.  We download the first
+//! one and concatenate the sentence texts.
+
+use std::time::Duration;
+
+use serde::{Deserialize, Serialize};
+use serde_json::{json, Value};
+use thiserror::Error;
+use tokio::time::sleep;
+
+const SUBMIT_URL: &str =
+    "https://dashscope.aliyuncs.com/api/v1/services/audio/asr/transcription";
+const TASK_URL_PREFIX: &str = "https://dashscope.aliyuncs.com/api/v1/tasks/";
+
+#[derive(Debug, Error)]
+pub enum AsrError {
+    #[error("missing api key")]
+    MissingApiKey,
+    #[error("http: {0}")]
+    Http(#[from] reqwest::Error),
+    #[error("dashscope: {0}")]
+    Api(String),
+    #[error("timeout waiting for asr task")]
+    Timeout,
+    #[error("json: {0}")]
+    Json(#[from] serde_json::Error),
+}
+
+#[derive(Debug, Deserialize, Serialize, Clone)]
+pub struct AsrSentence {
+    #[serde(default)]
+    pub text: String,
+    #[serde(default)]
+    pub begin_time: Option<i64>,
+    #[serde(default)]
+    pub end_time: Option<i64>,
+}
+
+#[derive(Debug, Serialize)]
+pub struct AsrResult {
+    pub success: bool,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub text: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub sentences: Option<Vec<AsrSentence>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub error: Option<String>,
+}
+
+pub async fn transcribe(
+    audio_url: &str,
+    api_key: &str,
+    model: &str,
+) -> Result<AsrResult, AsrError> {
+    if api_key.trim().is_empty() {
+        return Err(AsrError::MissingApiKey);
+    }
+    let client = reqwest::Client::builder()
+        .timeout(Duration::from_secs(60))
+        .build()?;
+
+    // 1) submit
+    let submit_body = json!({
+        "model": model,
+        "input": { "file_urls": [audio_url] },
+        "parameters": {}
+    });
+    let submit: Value = client
+        .post(SUBMIT_URL)
+        .bearer_auth(api_key)
+        .header("X-DashScope-Async", "enable")
+        .json(&submit_body)
+        .send()
+        .await?
+        .json()
+        .await?;
+    let task_id = submit
+        .pointer("/output/task_id")
+        .and_then(Value::as_str)
+        .ok_or_else(|| AsrError::Api(format!("submit: no task_id, raw={submit}")))?
+        .to_string();
+
+    // 2) poll
+    let max_polls = 60; // ~5 min @ 5s
+    let mut poll_resp: Value = Value::Null;
+    let mut succeeded = false;
+    for _ in 0..max_polls {
+        sleep(Duration::from_secs(5)).await;
+        poll_resp = client
+            .get(format!("{TASK_URL_PREFIX}{task_id}"))
+            .bearer_auth(api_key)
+            .send()
+            .await?
+            .json()
+            .await?;
+        let status = poll_resp
+            .pointer("/output/task_status")
+            .and_then(Value::as_str)
+            .unwrap_or("");
+        match status {
+            "SUCCEEDED" => { succeeded = true; break; }
+            "FAILED" | "UNKNOWN" => {
+                let msg = poll_resp
+                    .pointer("/output/message")
+                    .and_then(Value::as_str)
+                    .unwrap_or("FAILED");
+                return Err(AsrError::Api(msg.to_string()));
+            }
+            _ => continue,
+        }
+    }
+    if !succeeded {
+        return Err(AsrError::Timeout);
+    }
+
+    // 3) fetch transcription file
+    let trans_url = poll_resp
+        .pointer("/output/results/0/transcription_url")
+        .and_then(Value::as_str)
+        .ok_or_else(|| AsrError::Api(format!("no transcription_url, raw={poll_resp}")))?
+        .to_string();
+    let trans_json: Value = client.get(&trans_url).send().await?.json().await?;
+
+    // dashscope transcription file shape:
+    //   { "transcripts": [{ "text": "...", "sentences": [{text, begin_time, end_time}, ...] }] }
+    let mut full_text = String::new();
+    let mut sentences = Vec::<AsrSentence>::new();
+    if let Some(transcripts) = trans_json.get("transcripts").and_then(Value::as_array) {
+        for t in transcripts {
+            if let Some(text) = t.get("text").and_then(Value::as_str) {
+                if !full_text.is_empty() { full_text.push('\n'); }
+                full_text.push_str(text);
+            }
+            if let Some(arr) = t.get("sentences").and_then(Value::as_array) {
+                for s in arr {
+                    sentences.push(AsrSentence {
+                        text: s.get("text").and_then(Value::as_str).unwrap_or("").to_string(),
+                        begin_time: s.get("begin_time").and_then(Value::as_i64),
+                        end_time: s.get("end_time").and_then(Value::as_i64),
+                    });
+                }
+            }
+        }
+    } else if let Some(text) = trans_json.get("text").and_then(Value::as_str) {
+        full_text.push_str(text);
+    }
+
+    Ok(AsrResult {
+        success: true,
+        text: Some(full_text),
+        sentences: if sentences.is_empty() { None } else { Some(sentences) },
+        error: None,
+    })
+}