Initial commit

src/hooks/use-db-message-detail.ts

@@ -0,0 +1,162 @@
+"use client"
+
+import { useCallback, useEffect, useMemo, useState } from "react"
+import { getFolderConversation } from "@/lib/tauri"
+import type { DbConversationDetail } from "@/lib/types"
+
+// Module-level cache: survives component unmount/remount
+const detailCache = new Map<number, DbConversationDetail>()
+const detailListeners = new Map<
+  number,
+  Set<(detail: DbConversationDetail) => void>
+>()
+
+function publishDetail(conversationId: number, detail: DbConversationDetail) {
+  const listeners = detailListeners.get(conversationId)
+  if (!listeners || listeners.size === 0) return
+  for (const listener of listeners) {
+    listener(detail)
+  }
+}
+
+function setCachedDetail(conversationId: number, detail: DbConversationDetail) {
+  detailCache.set(conversationId, detail)
+  publishDetail(conversationId, detail)
+}
+
+function subscribeDetail(
+  conversationId: number,
+  listener: (detail: DbConversationDetail) => void
+) {
+  let listeners = detailListeners.get(conversationId)
+  if (!listeners) {
+    listeners = new Set()
+    detailListeners.set(conversationId, listeners)
+  }
+  listeners.add(listener)
+
+  return () => {
+    const current = detailListeners.get(conversationId)
+    if (!current) return
+    current.delete(listener)
+    if (current.size === 0) {
+      detailListeners.delete(conversationId)
+    }
+  }
+}
+
+/** Invalidate cached detail so the next mount re-fetches from disk. */
+export function invalidateDetailCache(conversationId: number) {
+  detailCache.delete(conversationId)
+}
+
+interface State {
+  key: number
+  detail: DbConversationDetail | null
+  loading: boolean
+  error: string | null
+  fetchSeq: number
+}
+
+export function useDbMessageDetail(conversationId: number) {
+  const getCachedState = useCallback((id: number): State => {
+    const cached = detailCache.get(id)
+    return {
+      key: id,
+      detail: cached ?? null,
+      loading: !cached,
+      error: null,
+      fetchSeq: 0,
+    }
+  }, [])
+
+  const [state, setState] = useState<State>(() => {
+    return getCachedState(conversationId)
+  })
+
+  const derivedState =
+    state.key === conversationId ? state : getCachedState(conversationId)
+
+  useEffect(
+    () =>
+      subscribeDetail(conversationId, (detail) => {
+        setState((prev) =>
+          prev.key === conversationId
+            ? { ...prev, detail, loading: false, error: null }
+            : prev
+        )
+      }),
+    [conversationId]
+  )
+
+  const refetch = useCallback(() => {
+    detailCache.delete(conversationId)
+    setState((prev) => {
+      const base =
+        prev.key === conversationId ? prev : getCachedState(conversationId)
+      return {
+        ...base,
+        key: conversationId,
+        loading: true,
+        error: null,
+        fetchSeq: base.fetchSeq + 1,
+      }
+    })
+  }, [conversationId, getCachedState])
+
+  useEffect(() => {
+    // Skip fetch if cache already has data
+    if (detailCache.has(conversationId)) return
+
+    let cancelled = false
+    getFolderConversation(conversationId)
+      .then((d) => {
+        setCachedDetail(conversationId, d)
+        if (!cancelled) {
+          setState((prev) =>
+            prev.key === conversationId
+              ? { ...prev, detail: d, loading: false, error: null }
+              : {
+                  key: conversationId,
+                  detail: d,
+                  loading: false,
+                  error: null,
+                  fetchSeq: 0,
+                }
+          )
+        }
+      })
+      .catch((e) => {
+        if (!cancelled) {
+          setState((prev) =>
+            prev.key === conversationId
+              ? {
+                  ...prev,
+                  error: e instanceof Error ? e.message : String(e),
+                  loading: false,
+                }
+              : {
+                  key: conversationId,
+                  detail: null,
+                  loading: false,
+                  error: e instanceof Error ? e.message : String(e),
+                  fetchSeq: 0,
+                }
+          )
+        }
+      })
+    return () => {
+      cancelled = true
+    }
+  }, [conversationId, derivedState.fetchSeq])
+
+  return useMemo(
+    () => ({
+      detail: derivedState.detail,
+      loading: derivedState.loading,
+      error: derivedState.error,
+      refetch,
+    }),
+    [derivedState.detail, derivedState.loading, derivedState.error, refetch]
+  )
+}