fix: japanese characters not truncated correctly in tui terminal output

5 files changed, 80 insertions, 10 deletions

diff --git a/app/tests/test_runview.py b/app/tests/test_runview.py
index 8feeee1..3f77ed0 100644
--- a/app/tests/test_runview.py
+++ b/app/tests/test_runview.py
@@ -62,10 +62,21 @@ class FormatTests(_FakeTui, unittest.TestCase):
         self.assertEqual(runview._fit("hello", 3), "he~")
         self.assertEqual(runview._fit("hi", 10), "hi")
 
+    def test_fit_truncates_wide_characters_by_display_columns(self):
+        # Japanese characters fill two terminal cells each, so fitting
+        # by character count would let lines overflow their pane.
+        self.assertEqual(runview._fit("你好", 4), "你好")
+        self.assertEqual(runview._fit("你好你好", 5), "你好~")
+        self.assertEqual(runview._fit("こんにちは", 3), "こ~")
+
     def test_wrap_wraps_on_word_boundaries(self):
         self.assertEqual(runview._wrap("aaaa bbbb cccc dddd", 12),
                          ["aaaa bbbb", "cccc dddd"])
 
+    def test_wrap_counts_wide_characters_as_two_columns(self):
+        self.assertEqual(runview._wrap("日本語 テスト", 10),
+                         ["日本語", "テスト"])
+
 
 class StateTransitionTests(_FakeTui, unittest.TestCase):
     def test_boot_flow_starting_to_ready(self):
diff --git a/app/tests/test_taskview.py b/app/tests/test_taskview.py
index 1db708d..78cc2f1 100644
--- a/app/tests/test_taskview.py
+++ b/app/tests/test_taskview.py
@@ -725,6 +725,25 @@ class LanesViewTests(_FakeTui, unittest.TestCase):
         pane_w = (screen.width - 3) // 2
         self.assertLessEqual(x + len(label) - 1, 1 + pane_w - 2)
 
+    def test_split_render_truncates_wide_log_lines_to_their_pane(self):
+        # Regression: Japanese characters fill two terminal cells each,
+        # so fitting by character count let transcription results spill
+        # out of the right pane onto the left one.
+        view, screen = self.make_view(self._two_lanes(), width=80)
+        view._ingest_lane_line(view._lanes[1],
+                               "[OK] 一号: " + "語" * 40)
+        view.render()
+        found = [(x, t) for _, x, t, _ in screen.strings
+                 if t.startswith("[OK] ")]
+        self.assertEqual(len(found), 1)
+        x, line = found[0]
+        self.assertTrue(line.endswith("~"))
+        pane_w = (screen.width - 3) // 2
+        px, pw = 1 + pane_w + 1, (screen.width - 3) - pane_w
+        self.assertGreaterEqual(x, px + 1)
+        self.assertLessEqual(x + taskview.tui._disp_width(line) - 1,
+                             px + pw - 2)
+
 
 class SilenceCueTests(_FakeTui, unittest.TestCase):
     """The "(no output 6m)" cue for a running step that stopped emitting."""
diff --git a/app/tests/test_tui.py b/app/tests/test_tui.py
index 6fc3fd5..4c8b431 100644
--- a/app/tests/test_tui.py
+++ b/app/tests/test_tui.py
@@ -1501,6 +1501,31 @@ class TextViewerTests(TuiTestCase):
         self.assertTrue(drawn[0].endswith("~"))
 
 
+class FitTests(TuiTestCase):
+    """Column-aware fitting: East Asian Wide characters occupy 2 cells."""
+
+    def test_disp_width_counts_wide_characters_twice(self):
+        self.assertEqual(tui._disp_width(""), 0)
+        self.assertEqual(tui._disp_width("hello"), 5)
+        self.assertEqual(tui._disp_width("一号"), 4)
+        self.assertEqual(tui._disp_width("mix語end"), 8)
+
+    def test_fit_truncates_by_display_columns(self):
+        self.assertEqual(tui._fit("hello", 3), "he~")
+        self.assertEqual(tui._fit("hi", 10), "hi")
+        # Exact fit keeps the wide pair; one column more would overflow.
+        self.assertEqual(tui._fit("你好", 4), "你好")
+        self.assertEqual(tui._fit("你好你好", 5), "你好~")
+        self.assertEqual(tui._fit("こんにちは", 3), "こ~")
+
+    def test_wrap_segments_counts_wide_characters_twice(self):
+        # "語 語 語" is 8 cells, so at width 5 only two words fit per
+        # line even though 5 characters would fit by count.
+        lines = tui._wrap_segments([("語 語 語", None)], 5)
+        self.assertEqual(["".join(t for t, _ in line) for line in lines],
+                         ["語 語", "語"])
+
+
 class WizardTests(unittest.TestCase):
     """The tui.Wizard screen-stack driver: Esc steps back one screen."""
 
diff --git a/app/ui/tui.py b/app/ui/tui.py
index b22a186..60e2dda 100644
--- a/app/ui/tui.py
+++ b/app/ui/tui.py
@@ -37,6 +37,7 @@ import contextlib
 import os
 import re
 import textwrap
+import unicodedata
 from pathlib import Path
 from typing import Callable, List, Optional, Sequence, Tuple, Union
 
@@ -255,13 +256,31 @@ def _hline(scr, y: int, x: int, n: int, attr: int = 0) -> None:
         pass
 
 
+def _char_width(ch: str) -> int:
+    """Terminal cells CH occupies (East Asian Wide/Fullwidth count 2)."""
+    return 2 if unicodedata.east_asian_width(ch) in ("W", "F") else 1
+
+
+def _disp_width(text: str) -> int:
+    """Terminal cells TEXT occupies (East Asian Wide/Fullwidth count 2)."""
+    return sum(_char_width(ch) for ch in text)
+
+
 def _fit(text: str, width: int) -> str:
     """Truncate TEXT to WIDTH columns, appending '~' when cut."""
     if width < 1:
         return ""
-    if len(text) <= width:
+    if _disp_width(text) <= width:
         return text
-    return text[: max(0, width - 1)] + "~"
+    out: List[str] = []
+    used = 0
+    for ch in text:
+        w = _char_width(ch)
+        if used + w > width - 1:
+            break
+        out.append(ch)
+        used += w
+    return "".join(out) + "~"
 
 
 def _wrap_segments(segments: Sequence[Tuple[str, int]], width: int
@@ -283,13 +302,13 @@ def _wrap_segments(segments: Sequence[Tuple[str, int]], width: int
     current: List[Tuple[str, int]] = []
     used = 0
     for text, attr in tokens:
-        if current and used + len(text) > width:
+        if current and used + _disp_width(text) > width:
             lines.append(current)
             current, used = [], 0
             if text.isspace():
                 continue  # the break eats the whitespace it happens at
         current.append((text, attr))
-        used += len(text)
+        used += _disp_width(text)
     if current:
         lines.append(current)
     return lines or [[]]
diff --git a/app/ui/viewkit.py b/app/ui/viewkit.py
index 301a0af..e54aada 100644
--- a/app/ui/viewkit.py
+++ b/app/ui/viewkit.py
@@ -217,11 +217,7 @@ def _sep(scr, curses, theme, y, width) -> None:
 
 def _fit(text: str, width: int) -> str:
     """Truncate TEXT to WIDTH columns, appending '~' when cut."""
-    if width < 1:
-        return ""
-    if len(text) <= width:
-        return text
-    return text[: max(0, width - 1)] + "~"
+    return tui._fit(text, width)
 
 
 def _wrap(text: str, width: int) -> List[str]:
@@ -230,7 +226,7 @@ def _wrap(text: str, width: int) -> List[str]:
     current = ""
     for word in text.split():
         candidate = f"{current} {word}".strip()
-        if len(candidate) <= max(10, width):
+        if tui._disp_width(candidate) <= max(10, width):
             current = candidate
         else:
             if current: