import { apiBaseUrl, apiFetch, buildAuthHeaders, refreshAccessToken, notifyAuthError, extractErrorMessage } from "./client.js";

export async function sendChatStream(message, { conversationId, mode, onChunk, onSources, onStatus, onDone, onError, signal } = {}) {
  const body = JSON.stringify({ message, ...(conversationId ? { conversationId } : {}), ...(mode ? { mode } : {}) });

  const doFetch = () =>
    fetch(`${apiBaseUrl}/api/chat/stream`, {
      method: "POST",
      headers: buildAuthHeaders(),
      body,
      signal
    });

  let res;
  try {
    res = await doFetch();

    if (res.status === 401) {
      let newToken = null;
      try {
        newToken = await refreshAccessToken();
      } catch {
        notifyAuthError();
        onError?.(new Error("session_expired"));
        return;
      }
      if (newToken) res = await doFetch();
    }
  } catch (e) {
    if (e?.name === "AbortError") return;
    onError?.(e);
    return;
  }

  if (res.status === 401) {
    notifyAuthError();
    onError?.(new Error("session_expired"));
    return;
  }

  if (!res.ok) {
    const text = await res.text().catch(() => "");
    onError?.(new Error(text || `http_error:${res.status}`));
    return;
  }

  const reader = res.body.getReader();
  const decoder = new TextDecoder();
  let buffer = "";

  const STREAM_INACTIVITY_TIMEOUT_MS = 45_000;
  function readWithTimeout() {
    return new Promise((resolve, reject) => {
      const timer = setTimeout(() => reject(new Error("stream_inactivity_timeout")), STREAM_INACTIVITY_TIMEOUT_MS);
      reader.read().then(
        (result) => { clearTimeout(timer); resolve(result); },
        (err) => { clearTimeout(timer); reject(err); }
      );
    });
  }

  try {
    while (true) {
      const { done, value } = await readWithTimeout();
      if (done) break;
      buffer += decoder.decode(value, { stream: true });
      const lines = buffer.split("\n");
      buffer = lines.pop() ?? "";
      for (const line of lines) {
        if (!line.startsWith("data: ")) continue;
        const payload = line.slice(6);
        if (payload === "[DONE]") { onDone?.(); return; }
        try {
          const parsed = JSON.parse(payload);
          if (parsed.type === "delta") onChunk?.(parsed.delta);
          else if (parsed.type === "sources") onSources?.(parsed.sources);
          else if (parsed.type === "status") onStatus?.(parsed);
          else if (parsed.type === "error") onError?.(new Error(parsed.error));
        } catch {}
      }
    }
  } catch (e) {
    if (e?.name === "AbortError") return;
    if (e?.message === "stream_inactivity_timeout") {
      reader.cancel().catch(() => {});
      onError?.(new Error("A resposta demorou demais e foi interrompida."));
      return;
    }
    onError?.(e);
  }

  onDone?.();
}

export async function ingestDocuments(documents) {
  return apiFetch("/api/ingest", {
    method: "POST",
    body: { documents }
  });
}

function sendIngestFile(file, { source, onProgress } = {}) {
  return new Promise((resolve, reject) => {
    const form = new FormData();
    form.append("file", file);
    if (source) form.append("source", source);

    const xhr = new XMLHttpRequest();

    xhr.upload.onprogress = (e) => {
      if (e.lengthComputable) onProgress?.(Math.round((e.loaded / e.total) * 100));
    };

    xhr.onload = () => {
      if (xhr.status >= 200 && xhr.status < 300) {
        try {
          resolve(JSON.parse(xhr.responseText));
        } catch {
          resolve(xhr.responseText);
        }
        return;
      }
      let payload = null;
      try { payload = JSON.parse(xhr.responseText); } catch {}
      const err = new Error(extractErrorMessage(payload, xhr.status));
      err.status = xhr.status;
      reject(err);
    };

    xhr.onerror = () => reject(new Error("network_error"));
    xhr.ontimeout = () => reject(new Error("timeout"));

    xhr.open("POST", `${apiBaseUrl}/api/ingest/file`);
    const authHeaders = buildAuthHeaders();
    if (authHeaders["Authorization"]) xhr.setRequestHeader("Authorization", authHeaders["Authorization"]);
    xhr.send(form);
  });
}

export async function ingestFile(file, { source, onProgress } = {}) {
  try {
    return await sendIngestFile(file, { source, onProgress });
  } catch (err) {
    if (err.status !== 401) throw err;
    try {
      await refreshAccessToken();
    } catch {
      notifyAuthError();
      throw new Error("session_expired");
    }
    return sendIngestFile(file, { source, onProgress });
  }
}

export async function ingestUrl(url, { source } = {}) {
  return apiFetch("/api/ingest/url", {
    method: "POST",
    body: { url, ...(source ? { source } : {}) }
  });
}

export async function search(query) {
  return apiFetch("/api/search", {
    method: "POST",
    body: { query }
  });
}

export async function listDocuments({ limit = 50, offset = 0 } = {}) {
  const params = new URLSearchParams({ limit: String(limit), offset: String(offset) }).toString();
  return apiFetch(`/api/documents?${params}`);
}

export async function deleteDocumentsBySource(source) {
  return apiFetch(`/api/documents/source/${encodeURIComponent(source)}`, {
    method: "DELETE"
  });
}