#!/usr/bin/env python3
"""The two things that drive shaders: focus, and a drag in progress.

Both are derived from the current frame rather than attached and remembered,
so most of what is worth checking is that they turn *off* again — a pane left
grey by a path that forgot to clear it is the failure mode this design exists
to make impossible.

Colours are asserted through the style runs the snapshot already reports, so
these are real end-to-end checks: a program's output, composed, shaded, and
read back the way a client would see it.
"""
import sys
import tempfile

from harness import Session, check, report

# A pane that paints a known, non-default colour into its own content.
GREEN = "#00ff00"
SH = ["/bin/sh", "-c",
      'printf "\\033]2;p\\007"; printf "\\033[38;2;0;255;0mBLOCK\\033[0m\\n"; '
      'stty raw -echo; cat']


def cfg(text):
    f = tempfile.NamedTemporaryFile("w", suffix=".kdl", delete=False)
    f.write(text)
    f.close()
    return f.name


def unfocused_cfg(amount):
    return "states {\n    unfocused { dim amount=%d }\n}\n" % amount


def drag_cfg(chain):
    """Both drop states get the same chain, which is what the defaults do."""
    return "states {\n    drop_target { %s }\n    drop_hover { %s }\n}\n" % (
        chain, chain)


def content_fg(snap, pane):
    """The colour of the pane's own first content cell."""
    run = snap.style_at(pane["content_x"], pane["content_y"])
    return (run or {}).get("fg")


def frame_fg(snap, pane):
    run = snap.style_at(pane["x"], pane["y"])
    return (run or {}).get("fg")


def check_at_rest(s, label):
    """Assert every pane looks the way it should with nothing transient going
    on: the one you are in keeps its colour, the others are pushed back.

    Stated as the rule rather than as "the same as before the drag", because a
    drag *moves focus* -- press a title and that pane is yours -- so the two
    panes legitimately swap appearances across one. Comparing to a remembered
    snapshot said they had both changed, which was true and not the point."""
    snap = s.snapshot()
    for p in s.panes():
        fg = content_fg(snap, p)
        ok = fg == GREEN if p["focused"] else fg not in (GREEN, None)
        check(f"{label}: pane {p['id']} is at rest",
              ok, f"{fg} (focused={p['focused']})")


def split(s):
    s.key("\\\\")
    s.settle()
    return s.panes()


def by_focus(s):
    panes = s.panes()
    focused = [p for p in panes if p["focused"]][0]
    other = [p for p in panes if not p["focused"]][0]
    return focused, other


def press(s, x, y):
    s.send(rf"\e[<0;{x + 1};{y + 1}M")


def motion(s, x, y):
    s.send(rf"\e[<32;{x + 1};{y + 1}M")


def release(s, x, y):
    s.send(rf"\e[<0;{x + 1};{y + 1}m")


# ---- the unfocused state ---------------------------------------------------

def test_the_default_dims_the_pane_you_are_not_in():
    """`dim_unfocused` writes the unfocused chain when a config has not, so out
    of the box the pane you left is pushed back and the one you are in is not.
    (This asserted the opposite until the knob existed to turn it off with.)"""
    with Session(SH, cols=80, rows=14) as s:
        s.until_text("BLOCK")
        split(s)
        focused, other = by_focus(s)
        snap = s.snapshot()
        check("the unfocused pane is dimmed",
              content_fg(snap, other) not in (GREEN, None),
              str(content_fg(snap, other)))
        check("and the focused one is left alone",
              content_fg(snap, focused) == GREEN,
              str(content_fg(snap, focused)))


def test_nothing_is_dimmed_with_the_knob_at_zero():
    with Session(SH, cols=80, rows=14, config=cfg("dim_unfocused 0\n")) as s:
        s.until_text("BLOCK")
        split(s)
        focused, other = by_focus(s)
        snap = s.snapshot()
        check("neither pane is touched",
              content_fg(snap, other) == GREEN and
              content_fg(snap, focused) == GREEN,
              f"{content_fg(snap, other)} {content_fg(snap, focused)}")


def test_dims_everything_but_the_focused_pane():
    with Session(SH, cols=80, rows=14, config=cfg(unfocused_cfg(128))) as s:
        s.until_text("BLOCK")
        split(s)
        focused, other = by_focus(s)
        snap = s.snapshot()
        check("the focused pane keeps its colour",
              content_fg(snap, focused) == GREEN,
              str(content_fg(snap, focused)))
        check("an unfocused pane is dimmed",
              content_fg(snap, other) not in (GREEN, None),
              str(content_fg(snap, other)))
        check("dimmed means darker, not merely different",
              int(content_fg(snap, other)[3:5], 16) < 0xff,
              str(content_fg(snap, other)))


def test_the_dimming_follows_focus():
    with Session(SH, cols=80, rows=14, config=cfg(unfocused_cfg(128))) as s:
        s.until_text("BLOCK")
        split(s)
        first_focused, first_other = by_focus(s)

        s.api("focus", id=first_other["id"])
        snap = s.snapshot()
        now_focused = [p for p in s.panes() if p["id"] == first_other["id"]][0]
        now_other = [p for p in s.panes() if p["id"] == first_focused["id"]][0]
        check("the newly focused pane is undimmed",
              content_fg(snap, now_focused) == GREEN,
              str(content_fg(snap, now_focused)))
        check("and the one that lost focus is dimmed now",
              content_fg(snap, now_other) not in (GREEN, None),
              str(content_fg(snap, now_other)))


def test_dimming_never_touches_the_chrome():
    with Session(SH, cols=80, rows=14, config=cfg(unfocused_cfg(200))) as s:
        s.until_text("BLOCK")
        split(s)
        _, other = by_focus(s)
        snap = s.snapshot()
        check("a dimmed pane's frame keeps its full colour",
              frame_fg(snap, other) == "#45454a", str(frame_fg(snap, other)))
        # Find where the strip actually starts rather than assuming a column:
        # status_pad decides that, and a test should not have an opinion on it.
        strip = snap.line(1)
        first = len(strip) - len(strip.lstrip())
        check("and the tab strip is untouched",
              "#" in str(snap.style_at(first, 1)),
              f"col {first}: " + str(snap.style_at(first, 1)))


# ---- the drag states -------------------------------------------------------

def test_dragging_greys_the_other_panes():
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        snap = s.snapshot()
        check("the pane being dragged keeps its colour",
              content_fg(snap, left) == GREEN, str(content_fg(snap, left)))
        check("every other pane goes grey",
              content_fg(snap, right) not in (GREEN, None),
              str(content_fg(snap, right)))
        # The default strength is 200, not 255: a partial desaturation that
        # keeps a trace of the original hue. So the test is that the channels
        # have converged, not that they are equal.
        grey = content_fg(snap, right)
        ch = [int(grey[i:i + 2], 16) for i in (1, 3, 5)]
        check("the colour has collapsed towards grey",
              max(ch) - min(ch) < 80, f"{grey} spread={max(ch) - min(ch)}")
        check("the two channels that started equal stay equal",
              ch[0] == ch[2], str(grey))

        release(s, right["x"] + 5, right["y"] + 3)
        check_at_rest(s, "after the drop")


def test_full_strength_is_a_true_grey():
    with Session(SH, cols=90, rows=16,
                 config=cfg(drag_cfg("grayscale amount=255"))) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        s.settle(120)
        grey = content_fg(s.snapshot(), right)
        check("at 255 every channel agrees exactly",
              grey and grey[1:3] == grey[3:5] == grey[5:7], str(grey))
        release(s, right["x"] + 5, right["y"] + 3)
        s.settle(120)


def test_a_press_that_never_moves_greys_nothing():
    """A click on a title is a click. It must not flash the session grey."""
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        press(s, left["x"] + 4, left["y"])
        check_at_rest(s, "a press that never moved")
        release(s, left["x"] + 4, left["y"])
        s.settle(120)


def test_the_drag_greying_outranks_the_focus_dimming():
    """Two reasons to be grey would compound into one muddy grey."""
    with Session(SH, cols=90, rows=16, config=cfg(unfocused_cfg(128))) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        # Drag the *unfocused* pane, so focus policy would dim it if it applied.
        focused, other = by_focus(s)
        press(s, other["x"] + 4, other["y"])
        motion(s, focused["x"] + 5, focused["y"] + 3)
        snap = s.snapshot()
        check("the dragged pane lifts off the page, dimming or not",
              content_fg(snap, other) == GREEN, str(content_fg(snap, other)))
        release(s, focused["x"] + 5, focused["y"] + 3)
        s.settle(200)


def drag_and_sample(conf):
    """Colour of a non-dragged pane's content mid-drag, under `conf`."""
    with Session(SH, cols=90, rows=16, config=cfg(conf)) as s:
        s.until_text("BLOCK")
        left, right = split(s)
        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        got = content_fg(s.snapshot(), right)
        release(s, right["x"] + 5, right["y"] + 3)
        s.settle(120)
        return got


def test_the_two_drag_knobs_are_independent():
    both_off = drag_and_sample(drag_cfg(""))
    check("with both off a drag leaves every pane alone", both_off == GREEN,
          str(both_off))

    # Desaturate only: channels converge, brightness roughly survives.
    gray_only = drag_and_sample(drag_cfg("grayscale amount=255"))
    ch = [int(gray_only[i:i + 2], 16) for i in (1, 3, 5)]
    check("grayscale alone desaturates without darkening much",
          ch[0] == ch[1] == ch[2] and ch[1] > 0x60, str(gray_only))

    # Darken only: the hue survives, the brightness does not.
    dim_only = drag_and_sample(drag_cfg("dim amount=200"))
    ch = [int(dim_only[i:i + 2], 16) for i in (1, 3, 5)]
    check("dim alone darkens without desaturating",
          ch[0] == 0 and ch[2] == 0 and 0 < ch[1] < 0x60, str(dim_only))


def test_the_default_drag_look_is_grey_and_recessed():
    """Both together: the dragged pane has to win on contrast, not just hue."""
    got = drag_and_sample("")
    ch = [int(got[i:i + 2], 16) for i in (1, 3, 5)]
    check("a non-dragged pane is pushed well below full brightness",
          max(ch) < 0x80, f"{got} max={max(ch):#x}")
    check("and towards grey", max(ch) - min(ch) < 60,
          f"{got} spread={max(ch) - min(ch)}")


# ---- the drop-target border (chrome, not a shader) -------------------------

DASH_H = "\u2504"
SOLID_H = "\u2500"


def test_non_dragged_panes_get_a_dashed_border():
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        snap = s.snapshot()
        check("borders are solid when nothing is being dragged",
              DASH_H not in snap.line(right["y"]), repr(snap.line(right["y"])))

        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        snap = s.snapshot()
        top = snap.line(right["y"])[right["x"]:right["x"] + right["w"]]
        dragged_top = snap.line(left["y"])[left["x"]:left["x"] + left["w"]]
        check("a pane you could drop onto is dashed", DASH_H in top, repr(top))
        check("the pane in your hand stays solid",
              DASH_H not in dragged_top and SOLID_H in dragged_top,
              repr(dragged_top))

        release(s, right["x"] + 5, right["y"] + 3)
        snap = s.snapshot()
        for p in s.panes():
            row = snap.line(p["y"])[p["x"]:p["x"] + p["w"]]
            check(f"pane {p['id']} is solid again after the drop",
                  DASH_H not in row, repr(row))


def test_a_press_that_never_moves_dashes_nothing():
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)
        press(s, left["x"] + 4, left["y"])
        snap = s.snapshot()
        check("pressing without moving dashes nothing",
              DASH_H not in snap.screen(), "")
        release(s, left["x"] + 4, left["y"])
        s.settle(120)


def test_the_hovered_target_is_still_highlighted_over_the_dashes():
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)
        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        snap = s.snapshot()
        run = snap.style_at(right["x"], right["y"])
        check("the pane under the pointer keeps its drop highlight",
              run and run["fg"] == "#ff5fd7" and "bold" in run["attrs"],
              str(run))
        release(s, right["x"] + 5, right["y"] + 3)
        s.settle(120)


def test_a_drag_that_ends_off_a_pane_still_clears():
    """The clear is derived, so even a drop into nowhere cannot leave it on."""
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        s.settle(120)
        motion(s, 0, 0)          # out into the margin
        release(s, 0, 0)
        check_at_rest(s, "a drop into nowhere")


def test_a_keystroke_mid_drag_clears_the_greying():
    """Any key ends a drag (so the mouse cannot wedge); colour must follow."""
    with Session(SH, cols=90, rows=16) as s:
        s.until_text("BLOCK")
        left, right = split(s)

        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        s.settle(120)
        s.send("x")
        check_at_rest(s, "a keystroke mid-drag")


# ---- the config block ------------------------------------------------------

def test_config_shaders_reach_the_screen():
    """`shaders { ... }` is the surface these are actually driven from."""
    conf = 'shaders {\n    ruler amount=255 at=4 color="#ff0000"\n}\n'
    with Session(SH, cols=60, rows=12, config=cfg(conf)) as s:
        s.until_text("BLOCK")
        p = s.pane()
        snap = s.snapshot()
        on = snap.style_at(p["content_x"] + 4, p["content_y"])
        off = snap.style_at(p["content_x"] + 3, p["content_y"])
        check("a configured ruler marks its column",
              (on or {}).get("bg") == "#ff0000", str(on))
        check("and leaves the neighbouring column alone",
              (off or {}).get("bg") != "#ff0000", str(off))


def test_config_shaders_run_in_written_order():
    """Order in the block is order in the chain."""
    a = 'shaders {\n    tint amount=255 color="#ff0000"\n    tint amount=255 color="#0000ff"\n}\n'
    b = 'shaders {\n    tint amount=255 color="#0000ff"\n    tint amount=255 color="#ff0000"\n}\n'
    def last(conf):
        with Session(SH, cols=50, rows=10, config=cfg(conf)) as s:
            s.settle(200)
            p = s.pane()
            return content_fg(s.snapshot(), p)
    check("the last shader written is the last one applied",
          last(a) == "#0000ff" and last(b) == "#ff0000",
          f"{last(a)} / {last(b)}")


def test_an_unknown_shader_is_refused_not_guessed():
    with Session(SH, cols=50, rows=10,
                 config=cfg('shaders {\n    bloom amount=255\n}\n')) as s:
        s.until_text("BLOCK")
        check("an unknown shader leaves the session running and unshaded",
              s.alive() and content_fg(s.snapshot(), s.pane()) == GREEN,
              str(content_fg(s.snapshot(), s.pane())))


def test_positional_shaders_stay_off_the_chrome():
    conf = 'shaders {\n    vignette amount=255\n    zebra amount=255 band=1\n}\n'
    with Session(SH, cols=60, rows=12, config=cfg(conf)) as s:
        s.until_text("BLOCK")
        p = s.pane()
        snap = s.snapshot()
        check("a full-strength positional stack still leaves the frame alone",
              frame_fg(snap, p) == "#ff5fd7", str(frame_fg(snap, p)))


# ---- states as a table -----------------------------------------------------

def lay(text):
    f = tempfile.NamedTemporaryFile("w", suffix=".kdl", delete=False)
    f.write(text)
    f.close()
    return f.name


def test_the_dragged_pane_can_have_a_state_of_its_own():
    conf = 'states {\n    dragging { tint amount=255 color="#0000ff" }\n}\n'
    with Session(SH, cols=90, rows=16, config=cfg(conf)) as s:
        s.until_text("BLOCK")
        left, right = split(s)
        press(s, left["x"] + 4, left["y"])
        motion(s, right["x"] + 5, right["y"] + 3)
        snap = s.snapshot()
        check("the pane in your hand takes the dragging state",
              content_fg(snap, left) == "#0000ff", str(content_fg(snap, left)))
        release(s, right["x"] + 5, right["y"] + 3)
        check_at_rest(s, "after the drop")


def test_the_hovered_pane_is_a_different_state_from_the_rest():
    conf = ('states {\n'
            '    drop_hover { tint amount=255 color="#ff0000" }\n'
            '    drop_target { tint amount=255 color="#0000ff" }\n'
            '}\n')
    with Session(SH, cols=120, rows=20, config=cfg(conf)) as s:
        s.settle(200)
        s.key("\\\\")
        s.settle(150)
        s.key("\\\\")
        s.settle(250)
        panes = sorted(s.panes(), key=lambda p: p["x"])
        if len(panes) < 3:
            check("three panes for the drop-state test", False, str(len(panes)))
            return
        a, b, c = panes
        press(s, a["x"] + 4, a["y"])
        motion(s, b["x"] + 3, b["y"] + 3)
        snap = s.snapshot()
        check("the pane under the pointer is the hover state",
              content_fg(snap, b) == "#ff0000", str(content_fg(snap, b)))
        check("the other candidates are the plain target state",
              content_fg(snap, c) == "#0000ff", str(content_fg(snap, c)))
        release(s, b["x"] + 3, b["y"] + 3)
        s.settle(150)


def test_a_suspended_pane_is_a_state():
    """It draws a label rather than a program, and that is still contents."""
    l = lay('layout {\n  tab name="t" {\n    pane\n'
            '    pane suspended=true command="sleep 1"\n  }\n}\n')
    conf = 'states {\n    suspended { tint amount=255 color="#00aaff" }\n}\n'
    with Session(SH, cols=90, rows=14, config=cfg(conf), layout=l) as s:
        s.settle(250)
        panes = s.panes()
        susp = [p for p in panes if p["suspended"]]
        check("the layout made a suspended pane", len(susp) == 1, str(panes))
        if not susp:
            return
        snap = s.snapshot()
        run = snap.style_at(susp[0]["content_x"] + susp[0]["content_w"] // 2,
                            susp[0]["content_y"] + susp[0]["content_h"] // 2)
        check("a suspended pane reaches the shader pass at all",
              (run or {}).get("fg") == "#00aaff", str(run))


def test_scrollback_is_a_state():
    noisy = ["/bin/sh", "-c",
             'printf "\\033]2;p\\007"; i=0; while [ $i -lt 200 ]; do '
             'printf "\\033[38;2;0;255;0mline %d\\033[0m\\n" $i; i=$((i+1)); done; '
             'stty raw -echo; cat']
    conf = 'states {\n    scrolled { tint amount=255 color="#ffaa00" }\n}\n'
    with Session(noisy, cols=80, rows=14, config=cfg(conf)) as s:
        s.settle(300)
        p = s.pane()
        check("not scrolled yet, so no state colour",
              content_fg(s.snapshot(), p) == GREEN,
              str(content_fg(s.snapshot(), p)))
        # No scroll command exists, so drive it the way a person does: the
        # wheel. SGR button 64 is wheel-up.
        for _ in range(6):
            s.send(rf"\e[<64;{p['content_x'] + 2};{p['content_y'] + 2}M")
        check("looking at the past is a state you can colour",
              content_fg(s.snapshot(), p) == "#ffaa00",
              str(content_fg(s.snapshot(), p)))


def test_exactly_one_state_wins():
    """A pane is in several at once; the ranking decides, and does not stack."""
    l = lay('layout {\n  tab name="t" {\n    pane\n'
            '    pane suspended=true command="sleep 1"\n  }\n}\n')
    conf = ('states {\n'
            '    suspended { tint amount=255 color="#00aaff" }\n'
            '    unfocused { tint amount=255 color="#ff0000" }\n'
            '}\n')
    with Session(SH, cols=90, rows=14, config=cfg(conf), layout=l) as s:
        s.settle(250)
        susp = [p for p in s.panes() if p["suspended"]]
        if not susp or susp[0]["focused"]:
            check("a suspended, unfocused pane to test with", bool(susp),
                  str(s.panes()))
            return
        run = s.snapshot().style_at(
            susp[0]["content_x"] + susp[0]["content_w"] // 2,
            susp[0]["content_y"] + susp[0]["content_h"] // 2)
        check("suspended outranks unfocused, and they do not mix",
              (run or {}).get("fg") == "#00aaff", str(run))


def test_an_unknown_state_is_refused():
    conf = 'states {\n    haunted { dim amount=255 }\n}\n'
    with Session(SH, cols=60, rows=12, config=cfg(conf)) as s:
        s.until_text("BLOCK")
        check("an unknown state name leaves the session running",
              s.alive() and content_fg(s.snapshot(), s.pane()) == GREEN,
              str(content_fg(s.snapshot(), s.pane())))


if __name__ == "__main__":
    test_the_default_dims_the_pane_you_are_not_in()
    test_nothing_is_dimmed_with_the_knob_at_zero()
    test_dims_everything_but_the_focused_pane()
    test_the_dimming_follows_focus()
    test_dimming_never_touches_the_chrome()
    test_dragging_greys_the_other_panes()
    test_full_strength_is_a_true_grey()
    test_a_press_that_never_moves_greys_nothing()
    test_the_drag_greying_outranks_the_focus_dimming()
    test_the_two_drag_knobs_are_independent()
    test_the_default_drag_look_is_grey_and_recessed()
    test_non_dragged_panes_get_a_dashed_border()
    test_a_press_that_never_moves_dashes_nothing()
    test_the_hovered_target_is_still_highlighted_over_the_dashes()
    test_a_drag_that_ends_off_a_pane_still_clears()
    test_a_keystroke_mid_drag_clears_the_greying()
    test_config_shaders_reach_the_screen()
    test_config_shaders_run_in_written_order()
    test_an_unknown_shader_is_refused_not_guessed()
    test_positional_shaders_stay_off_the_chrome()
    test_the_dragged_pane_can_have_a_state_of_its_own()
    test_the_hovered_pane_is_a_different_state_from_the_rest()
    test_a_suspended_pane_is_a_state()
    test_scrollback_is_a_state()
    test_exactly_one_state_wins()
    test_an_unknown_state_is_refused()
    sys.exit(report())