feat: 1-to-1 message render + web data-lake backend

frontend/src/lib/api/media.ts

@@ -0,0 +1,175 @@
+import { requestMedia } from "$lib/api/client";
+import { getMessageMedia } from "$lib/api/endpoints";
+import type { MediaRef } from "$lib/api/types";
+import { accounts } from "$lib/stores/accounts.svelte";
+
+export type InlineMedia =
+  | {
+      state: "ready";
+      mediaId: number;
+      kind: string;
+      mime: string | null;
+      url: string;
+      transcript: string | null;
+    }
+  | { state: "not-downloaded"; mediaId: number; kind: string }
+  | { state: "missing" };
+
+export interface ViewerItem {
+  downloaded: boolean;
+  kind: string;
+  mediaId: number | null;
+  messageId: number;
+}
+
+export function viewerItemsFrom(
+  messageId: number,
+  media: MediaRef[]
+): ViewerItem[] {
+  if (media.length === 0) {
+    return [{ messageId, mediaId: null, kind: "", downloaded: false }];
+  }
+  return media.map((item) => ({
+    messageId: item.message_id,
+    mediaId: item.id,
+    kind: item.kind,
+    downloaded: item.downloaded,
+  }));
+}
+
+export type VisualKind = "image" | "video" | "other";
+
+const VIDEO_KINDS = new Set(["video", "video_note", "animation", "gif"]);
+
+export function visualKind(kind: string): VisualKind {
+  if (kind === "photo") {
+    return "image";
+  }
+  if (VIDEO_KINDS.has(kind)) {
+    return "video";
+  }
+  return "other";
+}
+
+const ready = new Map<string, InlineMedia>();
+const inflight = new Map<string, Promise<InlineMedia>>();
+
+function cacheKey(account: number, chatId: number, messageId: number): string {
+  return `${account}:${chatId}:${messageId}`;
+}
+
+async function resolve(
+  chatId: number,
+  messageId: number
+): Promise<InlineMedia> {
+  let meta: Awaited<ReturnType<typeof getMessageMedia>>;
+  try {
+    meta = await getMessageMedia(chatId, messageId);
+  } catch {
+    return { state: "missing" };
+  }
+  if (!meta.downloaded) {
+    return { state: "not-downloaded", mediaId: meta.id, kind: meta.kind };
+  }
+  const blob = await requestMedia(meta.id);
+  if (blob.state === "ready") {
+    return {
+      state: "ready",
+      mediaId: meta.id,
+      kind: meta.kind,
+      mime: blob.mime,
+      url: blob.url,
+      transcript: meta.extracted_text,
+    };
+  }
+  if (blob.state === "not-downloaded") {
+    return { state: "not-downloaded", mediaId: meta.id, kind: meta.kind };
+  }
+  return { state: "missing" };
+}
+
+const byId = new Map<string, InlineMedia>();
+const byIdInflight = new Map<string, Promise<InlineMedia>>();
+
+async function resolveById(media: MediaRef): Promise<InlineMedia> {
+  if (media.id === null) {
+    return { state: "missing" };
+  }
+  if (!media.downloaded) {
+    return { state: "not-downloaded", mediaId: media.id, kind: media.kind };
+  }
+  const blob = await requestMedia(media.id);
+  if (blob.state === "ready") {
+    return {
+      state: "ready",
+      mediaId: media.id,
+      kind: media.kind,
+      mime: blob.mime,
+      url: blob.url,
+      transcript: null,
+    };
+  }
+  if (blob.state === "not-downloaded") {
+    return { state: "not-downloaded", mediaId: media.id, kind: media.kind };
+  }
+  return { state: "missing" };
+}
+
+export function loadMediaItem(media: MediaRef): Promise<InlineMedia> {
+  const account = accounts.selectedId;
+  if (account === null || media.id === null) {
+    return Promise.resolve<InlineMedia>({ state: "missing" });
+  }
+  const key = `${account}:${media.id}`;
+  const cached = byId.get(key);
+  if (cached) {
+    return Promise.resolve(cached);
+  }
+  const existing = byIdInflight.get(key);
+  if (existing) {
+    return existing;
+  }
+  const promise = resolveById(media)
+    .then((result) => {
+      if (result.state === "ready") {
+        byId.set(key, result);
+      }
+      return result;
+    })
+    .finally(() => {
+      byIdInflight.delete(key);
+    });
+  byIdInflight.set(key, promise);
+  return promise;
+}
+
+export function loadInlineMedia(
+  chatId: number,
+  messageId: number
+): Promise<InlineMedia> {
+  const account = accounts.selectedId;
+  if (account === null) {
+    return Promise.resolve<InlineMedia>({ state: "missing" });
+  }
+  const key = cacheKey(account, chatId, messageId);
+  const cached = ready.get(key);
+  if (cached) {
+    return Promise.resolve(cached);
+  }
+  const existing = inflight.get(key);
+  if (existing) {
+    return existing;
+  }
+  const promise = resolve(chatId, messageId)
+    .then((result) => {
+      if (result.state === "ready") {
+        ready.set(key, result);
+      }
+      return result;
+    })
+    .finally(() => {
+      inflight.delete(key);
+    });
+  inflight.set(key, promise);
+  return promise;
+}