path: root/app/tests/test_tui.py

"""Tests for the DOS-style curses TUI widgets in tui.py.

The widget module imports curses lazily, so these tests swap the
curses module for a small fake (patched into sys.modules) and drive
the widgets with scripted keys against a recording screen. That works
without a terminal and lets the tests assert exact drawing
coordinates: theme colors, the left margin of list rows, and that no
row ever paints over the dialog border.
"""

import sys
import tempfile
import unittest
from pathlib import Path
from unittest.mock import patch

from ui import tui


class FakeCurses:
    """Minimal curses stand-in: attributes, key codes, color pairs."""

    A_BOLD = 1
    A_DIM = 2
    A_REVERSE = 4

    COLOR_BLACK = 0
    COLOR_RED = 1
    COLOR_GREEN = 2
    COLOR_YELLOW = 3
    COLOR_BLUE = 4
    COLOR_MAGENTA = 5
    COLOR_CYAN = 6
    COLOR_WHITE = 7

    KEY_DOWN = 0x101
    KEY_UP = 0x102
    KEY_LEFT = 0x103
    KEY_RIGHT = 0x104
    KEY_HOME = 0x105
    KEY_END = 0x106
    KEY_PPAGE = 0x107
    KEY_NPAGE = 0x108
    KEY_BACKSPACE = 0x109
    KEY_BTAB = 0x10A

    ACS_ULCORNER = "ul"
    ACS_URCORNER = "ur"
    ACS_LLCORNER = "ll"
    ACS_LRCORNER = "lr"
    ACS_VLINE = "v"
    ACS_HLINE = "h"

    class error(Exception):
        pass

    def __init__(self):
        self.pairs = {}  # pair number -> (fg, bg)
        self.colors = True

    def has_colors(self):
        return self.colors

    def start_color(self):
        pass

    def init_pair(self, number, fg, bg):
        self.pairs[number] = (fg, bg)

    def color_pair(self, number):
        return number << 8

    def curs_set(self, visibility):
        pass

    def endwin(self):
        pass


class FakeScreen:
    """Recording curses window; getch() replays scripted keys."""

    def __init__(self, keys=(), width=80, height=24):
        self.keys = list(keys)
        self.width = width
        self.height = height
        self.strings = []  # (y, x, text, attr) from addstr
        self.chars = []    # (y, x, ch, attr) from addch

    def getmaxyx(self):
        return self.height, self.width

    def erase(self):
        pass

    def refresh(self):
        pass

    def bkgd(self, ch, attr):
        pass

    def addstr(self, y, x, text, attr=0):
        self.strings.append((y, x, text, attr))

    def addch(self, y, x, ch, attr=0):
        self.chars.append((y, x, ch, attr))

    def hline(self, y, x, ch, n, attr=0):
        pass

    def redrawwin(self):
        pass

    def getch(self):
        if not self.keys:
            raise AssertionError("the script ran out of keys")
        return self.keys.pop(0)


class TuiTestCase(unittest.TestCase):
    """Base class: fresh theme + fake curses module for every test."""

    def setUp(self):
        tui._THEME.clear()
        self.curses = FakeCurses()
        self.screen = FakeScreen()
        patcher = patch.dict(sys.modules, {"curses": self.curses})
        patcher.start()
        self.addCleanup(patcher.stop)
        self.addCleanup(tui._THEME.clear)

    def dialog_box(self, screen=None):
        """(x0, x_right) border columns of the drawn dialog."""
        screen = screen or self.screen
        corners = screen.chars[:2]
        self.assertEqual(corners[0][2], FakeCurses.ACS_ULCORNER)
        self.assertEqual(corners[1][2], FakeCurses.ACS_URCORNER)
        return corners[0][1], corners[1][1]

    def assert_inside_border(self, screen=None):
        """No drawn string may reach the right border column."""
        screen = screen or self.screen
        _, x_right = self.dialog_box(screen)
        for _, x, text, _ in screen.strings:
            self.assertLessEqual(
                x + len(text), x_right,
                f"{text!r} painted over the border at x={x}")


class ThemeTests(TuiTestCase):
    def test_desktop_and_message_backgrounds_are_black(self):
        frame = tui.Frame(self.screen, "Title", "footer")
        theme, pairs = frame.theme, self.curses.pairs
        for name in ("desktop", "border", "title", "ok", "warn", "err",
                     "info", "input", "check", "accent"):
            fg, bg = pairs[theme[name] >> 8]
            self.assertEqual(bg, FakeCurses.COLOR_BLACK, name)

    def test_cursor_bar_and_active_button_stand_out(self):
        frame = tui.Frame(self.screen, "Title", "footer")
        theme, pairs = frame.theme, self.curses.pairs
        fg, bg = pairs[theme["bar"] >> 8]
        self.assertEqual((fg, bg),
                         (FakeCurses.COLOR_BLACK, FakeCurses.COLOR_CYAN))
        fg, bg = pairs[theme["btn_on"] >> 8]
        self.assertEqual((fg, bg),
                         (FakeCurses.COLOR_BLACK, FakeCurses.COLOR_GREEN))

    def test_without_colors_theme_uses_plain_attributes(self):
        self.curses.colors = False
        frame = tui.Frame(self.screen, "Title", "footer")
        self.assertEqual(self.curses.pairs, {})
        self.assertEqual(frame.theme["desktop"], 0)
        self.assertEqual(frame.theme["title"], FakeCurses.A_BOLD)


class MenuTests(TuiTestCase):
    OPTIONS = [("first option", "one"), ("second option", "two")]

    def test_option_rows_left_justified_help_centered(self):
        screen = FakeScreen(keys=[10])
        value = tui.menu(screen, "Pick one", self.OPTIONS,
                         help_lines=["Help text"])
        self.assertEqual(value, "one")
        x0, x_right = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        for label in ("first option", "second option"):
            x = next(x for _, x, text, _ in screen.strings if text == label)
            self.assertEqual(x, margin, label)
        inner_w = x_right - x0 - 1
        help_x = next(x for _, x, text, _ in screen.strings
                      if text == "Help text")
        self.assertEqual(help_x, x0 + 1 + (inner_w - len("Help text")) // 2)
        self.assertGreater(help_x, margin)
        self.assert_inside_border(screen)

    def test_up_wraps_around_to_last_option(self):
        screen = FakeScreen(keys=[FakeCurses.KEY_UP, 10])
        value = tui.menu(screen, "Pick one", self.OPTIONS)
        self.assertEqual(value, "two")

    def test_no_option_painted_over_the_border(self):
        screen = FakeScreen(keys=[FakeCurses.KEY_END, 10])
        tui.menu(screen, "Pick", [("a" * 60, "a"), ("b", "b")])
        self.assert_inside_border(screen)

    def test_empty_options_rejected(self):
        with self.assertRaises(ValueError):
            tui.menu(self.screen, "Pick", [])

    def test_esc_returns_back_value(self):
        marker = object()
        screen = FakeScreen(keys=[27])
        self.assertIs(
            tui.menu(screen, "Pick", self.OPTIONS, back_value=marker),
            marker)

    def test_q_returns_back_value_like_esc(self):
        marker = object()
        screen = FakeScreen(keys=[ord("q")])
        self.assertIs(
            tui.menu(screen, "Pick", self.OPTIONS, back_value=marker),
            marker)

    def test_q_aborts_without_back_value(self):
        screen = FakeScreen(keys=[ord("q")])
        with self.assertRaises(tui.WizardCancelled):
            tui.menu(screen, "Pick", self.OPTIONS)


class MenuTableTests(TuiTestCase):
    """The optional status table: aligned columns and colored statuses."""

    ROWS = [("audio.cpp", "not installed", "err"),
            ("qwen-tts", "installed", "warn"),
            ("faster-qwen3-tts", "running", "ok")]

    def test_name_column_left_aligned_at_margin(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS)
        x0, _ = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        for name, _, _ in self.ROWS:
            x = next(x for _, x, text, _ in screen.strings
                     if text.rstrip() == name)
            self.assertEqual(x, margin, name)

    def test_status_column_aligned_at_one_fixed_offset(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS)
        x0, _ = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        name_w = max(len(name) for name, _, _ in self.ROWS)
        expected_x = margin + name_w  # the "  status" segment starts here
        for _, status, _ in self.ROWS:
            x = next(x for _, x, text, _ in screen.strings
                     if text.strip() == status)
            self.assertEqual(x, expected_x, status)

    def test_status_text_uses_the_theme_kind_color(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS)
        want = {"err": tui._THEME["err"], "warn": tui._THEME["warn"],
                "ok": tui._THEME["ok"]}
        for _, status, kind in self.ROWS:
            attr = next(a for _, _, text, a in screen.strings
                        if text.strip() == status)
            self.assertEqual(attr, want[kind], status)

    def test_optional_name_kind_colors_the_name_column(self):
        # 4-element rows: the 4th value is a theme kind for the name.
        rows = [("gone", "unavailable", "err", "dim"),
                ("here", "running", "ok", "body")]
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")], table_rows=rows)
        drawn = {text.rstrip(): attr for _, _, text, attr in screen.strings}
        self.assertEqual(drawn["gone"], tui._THEME["dim"])
        self.assertEqual(drawn["here"], tui._THEME["body"])

    def test_three_element_rows_default_to_body_names(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS)
        for name, _, _ in self.ROWS:
            attr = next(a for _, _, text, a in screen.strings
                        if text.rstrip() == name)
            self.assertEqual(attr, tui._THEME["body"], name)

    def test_table_title_is_dim_and_left_aligned(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS)
        x0, _ = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        x, attr = next((x, a) for _, x, text, a in screen.strings
                       if text == "Backend status")
        self.assertEqual(x, margin)
        self.assertEqual(attr, tui._THEME["dim"])

    def test_table_does_not_paint_over_the_border(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS)
        self.assert_inside_border(screen)

    def test_notice_line_is_red_and_above_the_table(self):
        screen = FakeScreen(keys=[10])
        tui.menu(screen, "Hub", [("Quit", "quit")],
                 table_title="Backend status", table_rows=self.ROWS,
                 notice_lines=[("Warning: ffmpeg not installed!", "err")])
        x0, _ = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        x, attr = next((x, a) for _, x, text, a in screen.strings
                       if text == "Warning: ffmpeg not installed!")
        self.assertEqual(x, margin)
        self.assertEqual(attr, tui._THEME["err"])
        # The notice sits above the table title ("Backend status").
        notice_y = next(y for y, _, text, _ in screen.strings
                        if text == "Warning: ffmpeg not installed!")
        title_y = next(y for y, _, text, _ in screen.strings
                       if text == "Backend status")
        self.assertLess(notice_y, title_y)
        self.assert_inside_border(screen)


class ConfirmTests(TuiTestCase):
    def test_tab_switches_and_enter_activates(self):
        screen = FakeScreen(keys=[9, 10])
        self.assertFalse(tui.confirm(screen, "Overwrite?", default=True))

    def test_y_answers_directly(self):
        screen = FakeScreen(keys=[ord("y")])
        self.assertTrue(tui.confirm(screen, "Overwrite?", default=False))

    def test_enter_takes_the_default(self):
        screen = FakeScreen(keys=[10])
        self.assertTrue(tui.confirm(screen, "Overwrite?", default=True))

    def test_esc_aborts_without_cancel_value(self):
        screen = FakeScreen(keys=[27])
        with self.assertRaises(tui.WizardCancelled):
            tui.confirm(screen, "Overwrite?", default=True)

    def test_esc_returns_cancel_value(self):
        marker = object()
        screen = FakeScreen(keys=[27])
        self.assertIs(
            tui.confirm(screen, "Overwrite?", default=True,
                        cancel_value=marker),
            marker)

    def test_q_returns_cancel_value(self):
        marker = object()
        screen = FakeScreen(keys=[ord("q")])
        self.assertIs(
            tui.confirm(screen, "Overwrite?", default=True,
                        cancel_value=marker),
            marker)


class LineEditTests(TuiTestCase):
    def test_typing_backspace_and_enter(self):
        keys = [ord("c"), ord("d"), FakeCurses.KEY_BACKSPACE, 10]
        screen = FakeScreen(keys=keys)
        value = tui.line_edit(screen, "Edit", "ab")
        self.assertEqual(value, "abc")

    def test_validation_error_keeps_editing(self):
        keys = [ord("x"), 10, FakeCurses.KEY_BACKSPACE, 10]
        screen = FakeScreen(keys=keys)
        value = tui.line_edit(
            screen, "Edit", "5",
            validate=lambda s: None if s.isdigit() else "digits only")
        self.assertEqual(value, "5")

    def test_esc_returns_back_value(self):
        marker = object()
        screen = FakeScreen(keys=[27])
        self.assertIs(
            tui.line_edit(screen, "Edit", "text", back_value=marker),
            marker)

    def test_q_stays_typeable_with_back_value(self):
        marker = object()
        screen = FakeScreen(keys=[ord("q"), 10])
        value = tui.line_edit(screen, "Edit", "te", back_value=marker)
        self.assertEqual(value, "teq")


class FormTests(TuiTestCase):
    def _fields(self):
        # Fresh dicts each call: form() edits field values in place, and a
        # shared class attribute would leak edits between tests.
        return [
            {"key": "fmt", "label": "Format", "kind": "choice",
             "value": "m4b", "choices": ["mp3", "m4b", "ogg"]},
            {"key": "chunk", "label": "Chunk", "kind": "text",
             "value": "250"},
        ]

    def test_save_returns_current_values(self):
        screen = FakeScreen(keys=[9, 10])  # Tab -> Save, Enter
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})

    def test_cancel_returns_back_value(self):
        marker = object()
        # Tab -> buttons, Left -> Cancel, Enter.
        screen = FakeScreen(keys=[9, FakeCurses.KEY_LEFT, 10])
        result = tui.form(screen, "Settings", self._fields(),
                          back_value=marker)
        self.assertIs(result, marker)

    def test_down_on_last_field_moves_to_save(self):
        # Down moves cursor to the last field, Down again steps onto the
        # Save button, Enter saves.
        screen = FakeScreen(keys=[FakeCurses.KEY_DOWN, FakeCurses.KEY_DOWN,
                                  10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})

    def test_up_on_first_field_wraps_to_save(self):
        # Up from the first field wraps onto the Save button; Enter saves.
        screen = FakeScreen(keys=[FakeCurses.KEY_UP, 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})

    def test_k_on_first_field_wraps_to_save(self):
        screen = FakeScreen(keys=[ord("k"), 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})

    def test_k_on_buttons_returns_to_fields(self):
        # Down to the last field, Down onto Save, k back into the fields;
        # editing then proves focus left the button row.
        screen = FakeScreen(keys=[FakeCurses.KEY_DOWN, FakeCurses.KEY_DOWN,
                                  ord("k"), 10, ord("x"), 10, 9, 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250x"})

    def test_j_on_cancel_returns_to_fields(self):
        # Up wraps to Save, Left to Cancel, j back into the fields; the
        # choice editor opening proves focus left the button row.
        screen = FakeScreen(keys=[FakeCurses.KEY_UP, FakeCurses.KEY_LEFT,
                                  ord("j"), 10, 10, 9, 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})

    def test_up_down_on_buttons_returns_to_fields(self):
        # Down (last field -> Save), Up returns to the last field, Enter
        # opens its text editor, then Tab -> Save, Enter.
        screen = FakeScreen(keys=[FakeCurses.KEY_DOWN, FakeCurses.KEY_DOWN,
                                  FakeCurses.KEY_UP, 10, ord("x"), 10,
                                  9, 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250x"})

    def test_esc_returns_back_value(self):
        marker = object()
        screen = FakeScreen(keys=[27])
        self.assertIs(
            tui.form(screen, "Settings", self._fields(), back_value=marker),
            marker)

    def test_q_returns_back_value_like_esc(self):
        marker = object()
        screen = FakeScreen(keys=[ord("q")])
        self.assertIs(
            tui.form(screen, "Settings", self._fields(), back_value=marker),
            marker)

    def test_choice_field_picks_another_value(self):
        # Enter opens the choice menu on 'm4b' (index 1); Down moves to
        # 'ogg', Enter accepts; Tab -> Save, Enter.
        screen = FakeScreen(keys=[10, FakeCurses.KEY_DOWN, 10, 9, 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "ogg", "chunk": "250"})

    def test_text_field_edits_then_saves(self):
        # Down to the text row, Enter opens the editor, type 'x', Enter,
        # then Tab -> Save, Enter.
        screen = FakeScreen(
            keys=[FakeCurses.KEY_DOWN, 10, ord("x"), 10, 9, 10])
        result = tui.form(screen, "Settings", self._fields())
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250x"})

    def test_validation_error_refuses_save_then_recovers(self):
        fields = [
            {"key": "chunk", "label": "Chunk", "kind": "text", "value": "bad",
             "validate": lambda s: None if s.isdigit() else "digits only"},
            {"key": "fmt", "label": "Format", "kind": "text", "value": "x"},
        ]
        # Tab->Save(Enter) fails, the flash consumes the next key; Enter
        # reopens the editor, Ctrl-U clears 'bad', type '120', Enter; then
        # Tab->Save(Enter).
        keys = [9, 10, 10, 10, 21, ord("1"), ord("2"), ord("0"), 10, 9, 10]
        screen = FakeScreen(keys=keys)
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"chunk": "120", "fmt": "x"})

    def test_rows_left_justified_inside_the_border(self):
        screen = FakeScreen(keys=[9, 10])
        tui.form(screen, "Settings", self._fields())
        self.assert_inside_border(screen)

    def test_empty_fields_rejected(self):
        with self.assertRaises(ValueError):
            tui.form(self.screen, "Settings", [])

    def test_field_note_renders_and_save(self):
        fields = self._fields()
        fields[1]["note"] = "A short section note"
        screen = FakeScreen(keys=[9, 10])
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})
        self.assert_inside_border(screen)

    def test_highlight_skips_note_rows_to_the_field(self):
        fields = self._fields()
        fields[1]["note"] = "A short section note"
        snapshots = []
        original_draw = tui.Frame.draw

        def spy(frame):
            original_draw(frame)
            snapshots.append((frame.cursor,
                              [row["text"] if row["segments"] is None
                               else "".join(text for text, _ in row["segments"])
                               for row in frame.rows]))

        # Down moves from the first field to the one after the note block.
        screen = FakeScreen(keys=[FakeCurses.KEY_DOWN, 9, 10])
        with patch.object(tui.Frame, "draw", spy):
            result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})
        cursor, texts = snapshots[1]
        # The cursor must sit on the Chunk field's own row — not on one
        # of the blank/note rows inserted above it (the old base+index
        # math highlighted the blank line).
        self.assertEqual(texts[cursor], "Chunk:   250")

    def test_custom_button_labels_and_start_on_buttons(self):
        # buttons= overrides the labels; start_on_buttons=True means Enter
        # alone (with no navigation) accepts the defaults.
        screen = FakeScreen(keys=[10])
        result = tui.form(screen, "Convert", self._fields(),
                          buttons=("Generate!", "Cancel"),
                          start_on_buttons=True)
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250"})
        texts = [text for _, _, text, _ in screen.strings]
        self.assertIn("[ Generate! ]", texts)
        self.assertIn("[ Cancel ]", texts)
        self.assertNotIn("[ Save ]", texts)

    def test_bool_field_toggles_with_enter(self):
        fields = [{"key": "combine", "label": "Combine", "kind": "bool",
                   "value": False}]
        # Enter toggles the bool to True, Tab -> button, Enter saves.
        screen = FakeScreen(keys=[10, 9, 10])
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"combine": True})

    def test_bool_field_toggles_with_space(self):
        fields = [{"key": "combine", "label": "Combine", "kind": "bool",
                   "value": False}]
        screen = FakeScreen(keys=[ord(" "), 9, 10])
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"combine": True})

    def test_hidden_field_keeps_value_and_is_not_drawn(self):
        fields = self._fields()
        fields.append({"key": "hidden", "label": "Secret", "kind": "text",
                       "value": "kept", "visible": False})
        screen = FakeScreen(keys=[9, 10])
        result = tui.form(screen, "Settings", fields)
        # The hidden field's value is preserved and returned.
        self.assertEqual(result, {"fmt": "m4b", "chunk": "250",
                                  "hidden": "kept"})
        texts = [text for _, _, text, _ in screen.strings]
        self.assertNotIn("Secret:", texts)

    def test_visible_callable_hides_row_after_change(self):
        fields = [
            {"key": "fmt", "label": "Format", "kind": "choice",
             "value": "mp3", "choices": ["mp3", "m4b"]},
            {"key": "combine", "label": "Combine", "kind": "bool",
             "value": False,
             "visible": lambda fs: next(
                 f["value"] for f in fs if f["key"] == "fmt") != "m4b"},
        ]
        snapshots = []
        original_draw = tui.Frame.draw

        def spy(frame):
            original_draw(frame)
            snapshots.append([row["text"] if row["segments"] is None
                              else "".join(t for t, _ in row["segments"])
                              for row in frame.rows])

        # Enter on Format, Down to m4b, Enter; Tab -> button, Enter.
        screen = FakeScreen(keys=[10, FakeCurses.KEY_DOWN, 10, 9, 10])
        with patch.object(tui.Frame, "draw", spy):
            result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"fmt": "m4b", "combine": False})
        self.assertTrue(any("Combine:" in row for row in snapshots[0]))
        self.assertFalse(any("Combine:" in row for row in snapshots[-1]))

    def test_callable_choices_resolve_at_open(self):
        fields = [{"key": "fmt", "label": "Format", "kind": "choice",
                   "value": "a", "choices": lambda fs: ["a", "b", "c"]}]
        screen = FakeScreen(keys=[10, FakeCurses.KEY_DOWN, 10, 9, 10])
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"fmt": "b"})

    def test_on_change_fires_after_value_change(self):
        calls = []
        fields = [{"key": "fmt", "label": "Format", "kind": "choice",
                   "value": "a", "choices": ["a", "b"],
                   "on_change": lambda fs: calls.append("changed")}]
        screen = FakeScreen(keys=[10, FakeCurses.KEY_DOWN, 10, 9, 10])
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"fmt": "b"})
        self.assertEqual(calls, ["changed"])

    def test_choice_field_validation_refuses_save(self):
        fields = [
            {"key": "fmt", "label": "Format", "kind": "choice",
             "value": "bad", "choices": ["good", "bad"],
             "validate": lambda v: None if v == "good" else "pick good"},
            {"key": "other", "label": "Other", "kind": "text", "value": "x"},
        ]
        # Tab -> Save fails on fmt; the flash consumes the next key; then
        # re-open fmt, Down to 'good', Enter; Tab -> Save, Enter.
        keys = [9, 10, 10, 10, FakeCurses.KEY_DOWN, 10, 9, 10]
        screen = FakeScreen(keys=keys)
        result = tui.form(screen, "Settings", fields)
        self.assertEqual(result, {"fmt": "good", "other": "x"})

    def _two_text_fields(self):
        return [{"key": "first", "label": "First", "kind": "text",
                 "value": "a"},
                {"key": "second", "label": "Second", "kind": "text",
                 "value": "b"}]

    def test_up_from_buttons_lands_on_last_field(self):
        # Focus starts on Generate!; Up wraps up through it onto the last
        # field (the list wraps: Up from the first button -> the bottom).
        screen = FakeScreen(keys=[
            FakeCurses.KEY_UP, 10, ord("x"), 10, 9, 10])
        result = tui.form(screen, "Convert", self._two_text_fields(),
                          buttons=("Generate!", "Cancel"),
                          start_on_buttons=True)
        self.assertEqual(result, {"first": "a", "second": "bx"})

    def test_down_from_buttons_lands_on_first_field(self):
        # Down wraps down through the buttons back onto the first field.
        screen = FakeScreen(keys=[
            FakeCurses.KEY_DOWN, 10, ord("x"), 10, 9, 10])
        result = tui.form(screen, "Convert", self._two_text_fields(),
                          buttons=("Generate!", "Cancel"),
                          start_on_buttons=True)
        self.assertEqual(result, {"first": "ax", "second": "b"})

    def test_k_from_buttons_lands_on_last_field(self):
        screen = FakeScreen(keys=[ord("k"), 10, ord("x"), 10, 9, 10])
        result = tui.form(screen, "Convert", self._two_text_fields(),
                          buttons=("Generate!", "Cancel"),
                          start_on_buttons=True)
        self.assertEqual(result, {"first": "a", "second": "bx"})

    def test_tab_from_buttons_lands_on_first_field(self):
        screen = FakeScreen(keys=[9, 10, ord("x"), 10, 9, 10])
        result = tui.form(screen, "Convert", self._two_text_fields(),
                          buttons=("Generate!", "Cancel"),
                          start_on_buttons=True)
        self.assertEqual(result, {"first": "ax", "second": "b"})

    def test_btab_from_buttons_lands_on_last_field(self):
        screen = FakeScreen(keys=[FakeCurses.KEY_BTAB, 10, ord("x"), 10,
                                  9, 10])
        result = tui.form(screen, "Convert", self._two_text_fields(),
                          buttons=("Generate!", "Cancel"),
                          start_on_buttons=True)
        self.assertEqual(result, {"first": "a", "second": "bx"})


class BrowseDirectoryTests(TuiTestCase):
    def setUp(self):
        super().setUp()
        tmp = tempfile.TemporaryDirectory()
        self.addCleanup(tmp.cleanup)
        self.root = Path(tmp.name)
        for name in ("alpha", "beta", "zulu"):
            (self.root / name).mkdir()
        (self.root / "noise.txt").write_text("x", encoding="utf-8")

    def test_listing_rows_left_justified(self):
        screen = FakeScreen(keys=[10])
        chosen = tui.browse_directory(screen, "Pick", start=self.root)
        self.assertEqual(chosen, self.root.resolve())
        x0, x_right = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        for label in ("[ Use this directory ]", "..",
                      "alpha/", "beta/", "zulu/"):
            x = next(x for _, x, text, _ in screen.strings if text == label)
            self.assertEqual(x, margin, label)
        drawn = " ".join(text for _, _, text, _ in screen.strings)
        self.assertNotIn("noise.txt", drawn)
        self.assert_inside_border(screen)

    def test_enter_opens_highlighted_subdirectory(self):
        keys = [FakeCurses.KEY_DOWN, FakeCurses.KEY_DOWN, 10, 10]
        screen = FakeScreen(keys=keys)
        chosen = tui.browse_directory(screen, "Pick", start=self.root)
        self.assertEqual(chosen, (self.root / "alpha").resolve())
        self.assert_inside_border(screen)

    def test_esc_returns_back_value(self):
        marker = object()
        screen = FakeScreen(keys=[27])
        self.assertIs(
            tui.browse_directory(screen, "Pick", start=self.root,
                                 back_value=marker),
            marker)

    def test_q_returns_back_value_like_esc(self):
        marker = object()
        screen = FakeScreen(keys=[ord("q")])
        self.assertIs(
            tui.browse_directory(screen, "Pick", start=self.root,
                                 back_value=marker),
            marker)


class CheckboxTreeTests(TuiTestCase):
    FAMILIES = [
        {"label": "Family one", "detail": "tts",
         "options": [{"key": "pkg-a", "label": "pkg-a", "recommended": True},
                     {"key": "pkg-b", "label": "pkg-b", "recommended": False}]},
        {"label": "Family two", "detail": "tts, cloning",
         "options": [{"key": "pkg-c", "label": "pkg-c", "recommended": True}]},
    ]

    def test_nothing_selected_by_default(self):
        # Nothing is pre-checked: Enter alone flashes and waits, and a
        # selection only happens after Space checks an option. The first
        # Enter and the flash each consume a key.
        screen = FakeScreen(keys=[10, 10, ord(" "), 10])
        picked = tui.checkbox_tree(screen, "Pick models", self.FAMILIES)
        self.assertEqual(picked, [(0, "pkg-a")])

    def test_rows_left_justified_inside_the_border(self):
        screen = FakeScreen(keys=[ord(" "), 10])
        tui.checkbox_tree(screen, "Pick models", self.FAMILIES)
        x0, x_right = self.dialog_box(screen)
        margin = x0 + 1 + tui.Frame.LIST_MARGIN
        strings = sorted((y, x, text) for y, x, text, _ in screen.strings)
        # Family row: its checkbox starts at the margin.
        y_family = next(y for y, _, text in strings if text == "- Family one")
        family_box_x = next(x for y, x, text in strings
                            if y == y_family and text == "[x] ")
        self.assertEqual(family_box_x, margin)
        # Option row: its checkbox sits one indent (2 columns) deeper.
        option_box_x = next(x for y, x, text in strings
                            if text == "[x] " and y != y_family)
        self.assertEqual(option_box_x, margin + 4)
        self.assert_inside_border(screen)

    def test_long_indented_options_do_not_paint_over_the_border(self):
        # A wide screen keeps the dialog width driven by the option row
        # itself (not the footer), the geometry where the old centered
        # segments drawing could paint over the right border.
        families = [{"label": "F", "detail": "tts",
                     "options": [{"key": "long", "label": "x" * 60,
                                  "recommended": True}]}]
        screen = FakeScreen(keys=[ord(" "), 10], width=120)
        picked = tui.checkbox_tree(screen, "Pick", families)
        self.assertEqual(picked, [(0, "long")])
        self.assert_inside_border(screen)

    def test_space_checks_then_enter_accepts(self):
        screen = FakeScreen(keys=[ord(" "), 10])
        picked = tui.checkbox_tree(screen, "Pick models", self.FAMILIES)
        self.assertEqual(picked, [(0, "pkg-a")])

    def test_prechecked_selection_accepted_directly(self):
        # checked= seeds the tree (modify flow): Enter alone accepts the
        # pre-checked option without any key presses in between.
        screen = FakeScreen(keys=[10])
        picked = tui.checkbox_tree(
            screen, "Pick models", self.FAMILIES,
            checked={(0, "pkg-b"), (1, "pkg-c")})
        self.assertEqual(picked, [(0, "pkg-b"), (1, "pkg-c")])

    def test_prechecked_options_draw_as_checked(self):
        screen = FakeScreen(keys=[10])
        tui.checkbox_tree(screen, "Pick models", self.FAMILIES,
                          checked={(0, "pkg-b")})
        texts = [text for _, _, text, _ in screen.strings]
        # The pre-checked option row (indented) draws its box checked.
        self.assertIn("[x] ", texts)
        # ...and the family row is expanded (its options are listed).
        self.assertIn("- Family one", texts)

    def test_prechecked_family_cursor_starts_on_it(self):
        # Only the second family is pre-checked, so the cursor starts on it:
        # Space clears then re-checks that family (the cursor never moves).
        # If the cursor were still on the first family, the two Spaces would
        # check then clear family one and Enter would flash instead of
        # accepting anything.
        screen = FakeScreen(keys=[ord(" "), ord(" "), 10])
        picked = tui.checkbox_tree(
            screen, "Pick models", self.FAMILIES,
            checked={(1, "pkg-c")})
        self.assertEqual(picked, [(1, "pkg-c")])

    def test_empty_families_rejected(self):
        with self.assertRaises(ValueError):
            tui.checkbox_tree(self.screen, "Pick", [])

    def test_esc_returns_back_value(self):
        marker = object()
        screen = FakeScreen(keys=[27])
        self.assertIs(
            tui.checkbox_tree(screen, "Pick models", self.FAMILIES,
                              back_value=marker),
            marker)

    def test_q_returns_back_value_like_esc(self):
        marker = object()
        screen = FakeScreen(keys=[ord("q")])
        self.assertIs(
            tui.checkbox_tree(screen, "Pick models", self.FAMILIES,
                              back_value=marker),
            marker)


class SuspendTests(TuiTestCase):
    """tui.suspend leaves curses, runs code, then repaints."""

    def test_suspend_runs_block_and_restores(self):
        ran = []
        with tui.suspend(self.screen):
            ran.append("inside")
        self.assertEqual(ran, ["inside"])

    def test_suspend_always_restores_on_exception(self):
        class Boom(Exception):
            pass
        with self.assertRaises(Boom):
            with tui.suspend(self.screen):
                raise Boom()


class FlashTests(TuiTestCase):
    """tui.flash shows a notice until any key is pressed."""

    def test_notice_dismissed_by_any_key(self):
        screen = FakeScreen(keys=[10])
        # Should return (None) after consuming one key; not raise.
        tui.flash(screen, "a notice", kind="warn")
        self.assertEqual(screen.keys, [])

    def test_message_is_shown_without_a_notice_heading(self):
        screen = FakeScreen(keys=[10])
        tui.flash(screen, "No backend is installed", kind="warn")
        texts = [text for _, _, text, _ in screen.strings]
        self.assertNotIn("Notice", texts)
        # The warning itself is the dialog's content, in its kind color.
        attr = next(a for _, _, text, a in screen.strings
                    if text == "No backend is installed")
        self.assertEqual(attr, tui._THEME["warn"])
        self.assert_inside_border(screen)


class WizardTests(unittest.TestCase):
    """The tui.Wizard screen-stack driver: Esc steps back one screen."""

    def test_advances_to_the_final_value(self):
        called = []

        def one():
            called.append("one")
            return two

        def two():
            called.append("two")
            return {"done": True}

        wizard = tui.Wizard()
        self.assertEqual(wizard.run(one), {"done": True})
        self.assertEqual(called, ["one", "two"])

    def test_back_on_first_screen_aborts(self):
        wizard = tui.Wizard()

        def first():
            return tui.Wizard.BACK

        self.assertIsNone(wizard.run(first))

    def test_back_pops_to_the_previous_screen(self):
        calls = []

        def first():
            calls.append("first")
            # Esc on the re-shown first screen finishes the wizard.
            return second if calls.count("first") == 1 else {"done": True}

        def second():
            calls.append("second")
            return tui.Wizard.BACK

        wizard = tui.Wizard()
        self.assertEqual(wizard.run(first), {"done": True})
        self.assertEqual(calls, ["first", "second", "first"])

    def test_back_goes_one_screen_at_a_time(self):
        order = []

        def a():
            order.append("a")
            return b

        def b():
            order.append("b")
            return c if order.count("b") == 1 else {"done": True}

        def c():
            order.append("c")
            return tui.Wizard.BACK

        wizard = tui.Wizard()
        self.assertEqual(wizard.run(a), {"done": True})
        # Back from c lands on b (one screen), not a.
        self.assertEqual(order, ["a", "b", "c", "b"])

    def test_screen_returning_none_aborts(self):
        wizard = tui.Wizard()

        def first():
            return None

        self.assertIsNone(wizard.run(first))


if __name__ == "__main__":
    unittest.main()