# selftest_less.exp — drives less's pager half over a REAL pty.
#
# WHY THIS FILE EXISTS. less is two programs in one binary, selected by
# isatty(1). The one the piped runner reaches is a byte copier: main.c takes the
# `if (!is_tty)` branch and cat_file()s the input straight to stdout, so a build
# whose termcap/ncurses link was silently broken would still pass every
# non-interactive case in 70-less.test. Paging, end-of-file positioning and
# search only exist on a terminal, and these five cases are the only thing that
# says the pager — the whole point of the package — works on target.
#
# EVERY SESSION SIZES ITS OWN TERMINAL. expect's stty_init is not applied to the
# pty it allocates on this target — a fresh spawn reports the controlling
# console's geometry instead — so the `stty rows 24 columns 80` prefix is
# load-bearing: which corpus lines land on which screen is computed from LINES,
# and without it every needle below becomes a property of whoever ran the suite.
# 61-bitwise.test and 59-dialog.test carry the same prologue for the same reason.
#
# THE SCREEN ARITHMETIC, since the needles depend on it. At 24 rows less paints
# 23 corpus lines plus one status line, so screen 1 is line0000..line0022 and a
# single SPACE (forward one window) brings line0023..line0045. line0030 is
# therefore off screen 1 and on screen 2 — that gap is what makes L2page an
# assertion about paging rather than about the first repaint.
#
# THE MATCH STRINGS ARE WHOLE, UNHIGHLIGHTED LINE PREFIXES, deliberately. less
# wraps a search hit in standout (ESC[7m ... ESC[27m), so L4search matches the
# line's "line0150" prefix and NOT the "MARKER-LESS-BST" token it searched for —
# a needle inside the highlighted run would have escapes spliced through it.
#
# Emits LSX-OK/LSX-FAIL <case> lines for 70-less.test to grade, and ALL-LESS-OK
# only when all five passed.

log_user 0
set env(TERM) "xterm"
set timeout 20

set SIZE "stty rows 24 columns 80;"
set F [lindex $argv 0]

set fails 0
proc emit {verdict case detail} {
    global fails
    if {$verdict eq "FAIL"} { incr fails }
    puts "LSX-$verdict $case $detail"
}

spawn -noecho sh -c "$SIZE exec less $F"

# --- L1first: the pager painted its first screen -----------------------------
set seen 0
expect {
    "line0000" { set seen 1 }
    timeout    { }
    eof        { }
}
if {$seen} {
    emit OK L1first ""
} else {
    emit FAIL L1first "no line0000 — less never painted a first screen"
}

# --- L2page: SPACE advances one window ---------------------------------------
# line0030 is on screen 2 only; seeing it means the keystroke reached less and a
# whole window was scrolled, not merely that the file was dumped.
send -- " "
set paged 0
expect {
    "line0030" { set paged 1 }
    timeout    { }
    eof        { }
}
if {$paged} {
    emit OK L2page ""
} else {
    emit FAIL L2page "SPACE did not bring line0030 onto the screen"
}

# --- L3end: G goes to end-of-file --------------------------------------------
send -- "G"
set atend 0
expect {
    "line0199" { set atend 1 }
    timeout    { }
    eof        { }
}
if {$atend} {
    emit OK L3end ""
} else {
    emit FAIL L3end "G did not reach the last line (line0199)"
}

# --- L4search: /pattern finds a match 150 lines down -------------------------
# Back to the top first, so the search has to travel rather than match whatever
# happens to be under the cursor at end-of-file.
send -- "g"
expect {
    "line0000" { }
    timeout    { }
    eof        { }
}
send -- "/MARKER-LESS-BST\r"
set found 0
expect {
    "line0150" { set found 1 }
    timeout    { }
    eof        { }
}
if {$found} {
    emit OK L4search ""
} else {
    emit FAIL L4search "/MARKER-LESS-BST did not position on line0150"
}

# --- L5quit: q exits the pager cleanly ---------------------------------------
send -- "q"
expect { eof {} timeout {} }
lassign [wait] _pid _spawnid _oserr _rc
if {$_oserr == 0 && $_rc == 0} {
    emit OK L5quit ""
} else {
    emit FAIL L5quit "oserr=$_oserr rc=$_rc"
}

if {$fails == 0} { puts "ALL-LESS-OK" }