feat(sidebar-tabs): move tab bar from top into sidebar as vertical list

2 files changed, 145 insertions, 177 deletions

diff --git a/src/features/tabs/ui/TabBar.svelte b/src/features/tabs/ui/TabBar.svelte
deleted file mode 100644
index 211fd5c..0000000
--- a/src/features/tabs/ui/TabBar.svelte
+++ /dev/null
@@ -1,177 +0,0 @@
-<script lang="ts">
-  import type { Tab } from "../tabs";
-  import { isStuckToEnd, shortHandle } from "../tabs";
-
-  let {
-    tabs,
-    activeConversationId,
-    statusFor,
-    onSelect,
-    onClose,
-    onNewDraft,
-    onRename,
-  }: {
-    tabs: readonly Tab[];
-    activeConversationId: string | null;
-    /** Returns the conversation's lifecycle status, or undefined when unknown. */
-    statusFor?: (conversationId: string) => string | undefined;
-    onSelect: (conversationId: string) => void;
-    onClose: (conversationId: string) => void;
-    onNewDraft: () => void;
-    onRename?: (conversationId: string, title: string) => void;
-  } = $props();
-
-  // The new-chat button is `position: sticky; right: 0`. It floats over the tabs
-  // only while the strip overflows and isn't scrolled fully right; we square its
-  // right edge only in that "stuck" state. Pure decision (`isStuckToEnd`) +
-  // DOM-measurement at the edge here.
-  let scrollEl = $state<HTMLDivElement>();
-  let stuck = $state(false);
-
-  // Git-style short handle (shortest unique prefix) per open tab — the visible
-  // "tab ID". Derived from the set of open conversation ids; pure helper.
-  const handles = $derived.by(() => {
-    const ids = tabs.map((t) => t.conversationId);
-    const map = new Map<string, string>();
-    for (const id of ids) map.set(id, shortHandle(id, ids));
-    return map;
-  });
-
-  function recompute(): void {
-    const el = scrollEl;
-    if (el === undefined) {
-      stuck = false;
-      return;
-    }
-    stuck = isStuckToEnd({
-      scrollLeft: el.scrollLeft,
-      clientWidth: el.clientWidth,
-      scrollWidth: el.scrollWidth,
-    });
-  }
-
-  $effect(() => {
-    const el = scrollEl;
-    if (el === undefined) return;
-    // Re-evaluate when the tab set changes (overflow may appear/disappear).
-    void tabs;
-    recompute();
-
-    el.addEventListener("scroll", recompute, { passive: true });
-    const ro = typeof ResizeObserver !== "undefined" ? new ResizeObserver(recompute) : undefined;
-    ro?.observe(el);
-
-    return () => {
-      el.removeEventListener("scroll", recompute);
-      ro?.disconnect();
-    };
-  });
-  // Inline rename: double-click a tab's title to edit, Enter/blur to save.
-  let editingId = $state<string | null>(null);
-  let editValue = $state("");
-  let editEl = $state<HTMLInputElement>();
-
-  function startRename(tab: Tab): void {
-    if (onRename === undefined) return;
-    editingId = tab.conversationId;
-    editValue = tab.title;
-    // Focus the input after it renders.
-    queueMicrotask(() => editEl?.focus());
-  }
-
-  function commitRename(): void {
-    const id = editingId;
-    if (id !== null && onRename !== undefined) {
-      const trimmed = editValue.trim();
-      if (trimmed.length > 0) onRename(id, trimmed);
-    }
-    editingId = null;
-  }
-
-  function cancelRename(): void {
-    editingId = null;
-  }
-</script>
-
-<div bind:this={scrollEl} class="min-w-0 flex-1 overflow-x-auto">
-  <div class="tabs tabs-lift min-w-max">
-    {#each tabs as tab (tab.conversationId)}
-      <div
-        class="tab flex w-48 shrink-0 items-center gap-1.5"
-        class:tab-active={tab.conversationId === activeConversationId}
-        role="tab"
-        tabindex="0"
-        onclick={() => onSelect(tab.conversationId)}
-        onkeydown={(e) => {
-          if (e.key === "Enter") onSelect(tab.conversationId);
-        }}
-      >
-        <span
-          class="shrink-0 rounded bg-base-300 px-1 py-0.5 font-mono text-[10px] leading-none text-base-content/60"
-          title="Tab ID"
-        >
-          {handles.get(tab.conversationId) ?? tab.conversationId}
-        </span>
-        {#if editingId === tab.conversationId}
-          <input
-            bind:this={editEl}
-            bind:value={editValue}
-            class="min-w-0 flex-1 rounded bg-base-100 px-1 py-0.5 text-left text-sm outline outline-1 outline-primary"
-            onclick={(e) => e.stopPropagation()}
-            onkeydown={(e) => {
-              if (e.key === "Enter") {
-                e.preventDefault();
-                commitRename();
-              } else if (e.key === "Escape") {
-                e.preventDefault();
-                cancelRename();
-              }
-            }}
-            onblur={commitRename}
-          />
-        {:else}
-          <span
-            class="min-w-0 flex-1 cursor-pointer truncate text-left"
-            role="button"
-            tabindex="-1"
-            title={tab.title}
-            ondblclick={(e) => {
-              e.stopPropagation();
-              startRename(tab);
-            }}
-          >
-            {tab.title}
-          </span>
-        {/if}
-        {#if statusFor?.(tab.conversationId) === "active"}
-          <span class="loading loading-spinner loading-xs shrink-0 text-primary"></span>
-        {/if}
-        <button
-          class="btn btn-ghost btn-xs shrink-0"
-          aria-label="Close tab"
-          onclick={(e) => {
-            e.stopPropagation();
-            onClose(tab.conversationId);
-          }}
-        >
-          &times;
-        </button>
-      </div>
-    {/each}
-    <button
-      class="tab sticky right-0 z-10 bg-base-200 shadow-[-2px_0_4px_-1px_rgba(0,0,0,0.2)] {stuck
-        ? '!rounded-se-none !rounded-ee-none'
-        : ''}"
-      class:tab-active={activeConversationId === null}
-      aria-label="New chat"
-      onclick={() => onNewDraft()}
-    >
-      {#if activeConversationId === null}
-        <span class="max-w-[120px] truncate">New Chat</span>
-        <span class="btn btn-ghost btn-xs ml-1" aria-hidden="true">+</span>
-      {:else}
-        +
-      {/if}
-    </button>
-  </div>
-</div>
diff --git a/src/features/tabs/ui/TabList.svelte b/src/features/tabs/ui/TabList.svelte
new file mode 100644
index 0000000..efef4fa
--- /dev/null
+++ b/src/features/tabs/ui/TabList.svelte
@@ -0,0 +1,145 @@
+<script lang="ts">
+	import type { Tab } from "../tabs";
+	import { shortHandle } from "../tabs";
+
+	let {
+		tabs,
+		activeConversationId,
+		statusFor,
+		onSelect,
+		onClose,
+		onNewDraft,
+		onRename,
+	}: {
+		tabs: readonly Tab[];
+		activeConversationId: string | null;
+		/** Returns the conversation's lifecycle status, or undefined when unknown. */
+		statusFor?: (conversationId: string) => string | undefined;
+		onSelect: (conversationId: string) => void;
+		onClose: (conversationId: string) => void;
+		onNewDraft: () => void;
+		onRename?: (conversationId: string, title: string) => void;
+	} = $props();
+
+	// Git-style short handle (shortest unique prefix) per open tab — the visible
+	// "tab ID". Derived from the set of open conversation ids; pure helper.
+	const handles = $derived.by(() => {
+		const ids = tabs.map((t) => t.conversationId);
+		const map = new Map<string, string>();
+		for (const id of ids) map.set(id, shortHandle(id, ids));
+		return map;
+	});
+
+	// Inline rename: double-click a tab's title to edit, Enter/blur to save.
+	let editingId = $state<string | null>(null);
+	let editValue = $state("");
+	let editEl = $state<HTMLInputElement>();
+
+	function startRename(tab: Tab): void {
+		if (onRename === undefined) return;
+		editingId = tab.conversationId;
+		editValue = tab.title;
+		// Focus the input after it renders.
+		queueMicrotask(() => editEl?.focus());
+	}
+
+	function commitRename(): void {
+		const id = editingId;
+		if (id !== null && onRename !== undefined) {
+			const trimmed = editValue.trim();
+			if (trimmed.length > 0) onRename(id, trimmed);
+		}
+		editingId = null;
+	}
+
+	function cancelRename(): void {
+		editingId = null;
+	}
+</script>
+
+<div class="flex flex-col gap-2">
+	<!-- Single-column vertical tab list. Capped at 80% of the viewport height
+	     so a long tab set scrolls inside this region instead of growing the
+	     whole sidebar. -->
+	<div class="flex max-h-[80vh] flex-col gap-1 overflow-y-auto pr-1">
+		{#each tabs as tab (tab.conversationId)}
+			<div
+				class="flex items-center gap-1.5 rounded px-2 py-1.5 text-sm hover:bg-base-200"
+				class:bg-base-300={tab.conversationId === activeConversationId}
+				role="tab"
+				tabindex="0"
+				aria-selected={tab.conversationId === activeConversationId}
+				title={tab.title}
+				onclick={() => onSelect(tab.conversationId)}
+				onkeydown={(e) => {
+					if (e.key === "Enter") onSelect(tab.conversationId);
+				}}
+			>
+				<span
+					class="shrink-0 rounded bg-base-300 px-1 py-0.5 font-mono text-[10px] leading-none text-base-content/60"
+					title="Tab ID"
+				>
+					{handles.get(tab.conversationId) ?? tab.conversationId}
+				</span>
+				{#if editingId === tab.conversationId}
+					<input
+						bind:this={editEl}
+						bind:value={editValue}
+						class="min-w-0 flex-1 rounded bg-base-100 px-1 py-0.5 text-left text-sm outline outline-1 outline-primary"
+						onclick={(e) => e.stopPropagation()}
+						onkeydown={(e) => {
+							if (e.key === "Enter") {
+								e.preventDefault();
+								commitRename();
+							} else if (e.key === "Escape") {
+								e.preventDefault();
+								cancelRename();
+							}
+						}}
+						onblur={commitRename}
+					/>
+				{:else}
+					<span
+						class="min-w-0 flex-1 cursor-pointer truncate text-left"
+						role="button"
+						tabindex="-1"
+						title={tab.title}
+						ondblclick={(e) => {
+							e.stopPropagation();
+							startRename(tab);
+						}}
+					>
+						{tab.title}
+					</span>
+				{/if}
+				{#if statusFor?.(tab.conversationId) === "active"}
+					<span class="loading loading-spinner loading-xs shrink-0 text-primary"></span>
+				{/if}
+				<button
+					class="btn btn-ghost btn-xs shrink-0"
+					aria-label="Close tab"
+					onclick={(e) => {
+						e.stopPropagation();
+						onClose(tab.conversationId);
+					}}
+				>
+					&times;
+				</button>
+			</div>
+		{/each}
+	</div>
+
+	<button
+		type="button"
+		class="btn btn-ghost btn-sm w-full border border-base-300"
+		class:btn-primary={activeConversationId === null}
+		aria-label="New chat"
+		onclick={() => onNewDraft()}
+	>
+		{#if activeConversationId === null}
+			New Chat
+		{:else}
+			+ New chat
+		{/if}
+	</button>
+</div>