. "$BST_LIB"
require mg mg/present

# BST-TIMEOUT: 600   # eleven pty sessions, each paced by settle delays past a repaint

# mg is the image's THIRD full-screen editor (58-nano.test has the first,
# 58-joe.test the second), so what this suite exists to answer is not "does a
# curses app run here" but the three things mg does that neither of those does:
#
#   1. mg READS THE DATABASE THROUGH THE TERMINFO API — setupterm() plus the
#      cursor_address / cursor_up / enter_ca_mode variables — where joe reads the
#      SAME entries through the termcap compatibility entry points. That makes mg
#      the control for brintos/linux-in-the-browser#152, which is specific to the
#      termcap half of the lookup: 58-joe.test carries three expected reds for it,
#      and the equivalent assertions here are expected GREEN. A red here and a red
#      there is a much larger defect than #152.
#   2. IT REFUSES A TERMINAL IT CANNOT ADDRESS, BY NAME. Under TERM=dumb mg exits
#      1 saying so, rather than painting at it. joe under dumb paints a degraded
#      screen and nano starts. This is the only case on the image that asserts a
#      terminfo lookup was consulted by observing a REFUSAL, which a fallback
#      guess cannot produce.
#   3. IT PROMPTS ON THE ECHO LINE FOR THINGS THE OTHER TWO DECIDE SILENTLY —
#      a missing trailing newline, a missing directory. Those prompts are a second
#      keyboard consumer with its own read path, and they are what a blind payload
#      must answer or hang on.
#
# THE ONE THING THIS SUITE DOES NOT DO IS DRIVE mg NON-INTERACTIVELY, and that is
# upstream's doing rather than this target's. See mg/batch-refused below.

# --- the surface that needs no terminal --------------------------------------
# These run before the pty leg on purpose: if expect is ever absent, the `require`
# below ends the file, and these have already reported. Every one of them is a
# path that returns BEFORE main() reaches vtinit(), which is why they work at all
# for a program that otherwise panics without a tty.

# mg has no --version and no --help; the usage line is what an unknown option
# prints, and __progname is what it names itself.
check_out mg/usage "usage: mg [-nR] [-b file] [-f mode] [-u file] [+number] [file ...]" \
  sh -c 'mg -Z 2>&1; exit 0'
check_rc  mg/usage-rc 1 mg -Z

# -b and -u both name a startup file and are rejected together, before either is
# opened. This one is asserted because it is the ONLY diagnostic on the -b path
# that a caller can read: everything after it goes to the pty mg makes for itself
# (see mg/batch-refused) and is therefore written to a terminal nobody holds.
check_out mg/opt-exclusive "-b and -u are mutually exclusive." \
  sh -c 'mg -b /dev/null -u /dev/null 2>&1; exit 0'

# -u with an unreadable startup file, and -f with a function that is not in the
# funmap: two different argument validations, both fatal, both diagnosed by name.
check_out mg/startup-missing "Problem with file: /nonexistent/mg-startup" \
  sh -c 'mg -u /nonexistent/mg-startup 2>&1; exit 0'
check_out mg/unknown-fn "Unknown function \`no-such-mg-function'" \
  sh -c 'mg -f no-such-mg-function /dev/null 2>&1; exit 0'

# No terminal at all: mg checks isatty() on stdin AND stdout and refuses. This is
# the assertion that says every case below genuinely needed the pty it was given.
check_out mg/needs-tty "standard input and output must be a terminal" \
  sh -c 'mg /dev/null < /dev/null 2>&1; exit 0'

# THE BATCH MODE, AND WHY IT IS NOT THIS TARGET'S FAULT.
#
# `mg -b <file>` is upstream's own regress harness: it calls openpty()+login_tty()
# to give itself a terminal and then runs <file> as an mg script. It cannot work
# on a Linux image, because tty.c:70 hardcodes the terminal NAME in batch mode --
#
#     if (batch == 1) tty = "pty"; else tty = NULL;
#     if (setupterm(tty, STDOUT_FILENO, &errret)) panic("Terminal setup failed");
#
# -- and `pty` is an OpenBSD terminfo entry. It is not in ncurses' base set, not
# in ncurses-terminfo-base which this image ships, and not in ncurses-term on a
# Debian host either. So setupterm() fails and mg exits 1 before reading a line of
# the script. VERIFIED ON BOTH ARMS: an x86_64 build of this same source, on a
# host with a working openpty(), exits 1 on the identical script. That is the null
# control, and it is what makes this NOT a wasm32 finding.
#
# The exit status is the whole of the observable behaviour: the panic message is
# written to fd 2, which login_tty() has already pointed at the pty mg allocated
# for itself and nobody reads. Asserted as 1 rather than as a message for that
# reason.
#
# The port does not ship a `pty` entry to make this work. Inventing a terminal
# name no other Linux distribution carries would make our image the odd one out
# and would be a divergence in the image rather than a fix in mg.
printf 'find-file "/dev/null"\n' > /tmp/bst-mg-batch.$$
check_rc mg/batch-refused 1 mg -b /tmp/bst-mg-batch.$$
rm -f /tmp/bst-mg-batch.$$

# --- the real test: a full-screen editor, driven over a real pty --------------
# Everything above is preamble; mg has no working batch mode, so expect supplies
# the pty. 45-expect.test covers whether that machinery works at all.
require expect mg/expect-present

work=${TMPDIR:-/tmp}/bst-mg.$$
mkdir -p "$work"
printf '%s\n' "hello world"                > "$work/typed.txt"
printf '%s\n' alpha bravo charlie          > "$work/cut.txt"
printf '%s\n' alpha bravo charlie          > "$work/arrow.txt"
printf '%s\n' alpha bravo charlie delta    > "$work/find.txt"
printf '%s\n' alpha bravo charlie          > "$work/repl.txt"
printf '%s\n' alpha bravo charlie          > "$work/ro.txt"
chmod 444 "$work/ro.txt"
printf '%s\n' alpha bravo charlie          > "$work/probe.txt"
# naive cafe, two CJK ideographs and an astral-plane earth: 2-, 3- and 4-byte UTF-8
printf 'na\303\257ve caf\303\251 \344\270\255\346\226\207 \360\237\214\215\n' > "$work/utf8.txt"
cp "$work/utf8.txt" "$work/utf8.want"

out=$(expect "$BST_DATA/selftest_mg.exp" "$work" 2>&1); rc=$?

case "$out" in *ALL-MG-OK*) all=1 ;; *) all=0 ;; esac
if [ "$rc" -eq 0 ] && [ "$all" -eq 1 ]; then bst_ok mg/all-ok
else bst_notok mg/all-ok "rc=$rc $(_bst_1line "$out")"; fi

# Each session reached a real terminal (terminfo resolved out of /etc/terminfo,
# curses init, first repaint) and left of its own accord with the status it should.
for tag in M1start M2exit M3cutexit M4arrowexit M5findexit M6replexit \
           M7newlineask M8nonlexit M9readonly M10roexit M11nodirask M12nodirexit \
           M13utf8exit M14linuxexit M15dumbrefused M16dumbexit; do
  case "$out" in
    *"M-$tag OK"*) bst_ok "mg/$tag" ;;
    *)             bst_notok "mg/$tag" "not OK in payload output (rc=$rc)" ;;
  esac
done

# paint <tag> <needle> : is the literal <needle> in that logged first paint?
paint() { grep -qaF -- "$2" "$work/raw-$1.bin" 2>/dev/null; }
# pcase <id> <want-present 1|0> <tag> <needle> <detail>
pcase() {
  if paint "$3" "$4"; then _got=1; else _got=0; fi
  if [ "$_got" = "$2" ]; then bst_ok "$1"; else bst_notok "$1" "$5"; fi
}
esc=$(printf '\033')

# --- THE TERMINFO VERDICT, AND WHY IT IS EXPECTED GREEN HERE ------------------
# mg calls setupterm() and then reads the terminfo VARIABLES (enter_ca_mode,
# clr_eos, enter_standout_mode). 58-joe.test's three reds are the termcap-name
# lookup returning an incomplete set for the same entries -- tgetstr("cl") and the
# standout pair come back NULL -- and that half is not on mg's path at all. So
# these assert the full paint, and a red here means the defect has spread from the
# termcap entry points into terminfo itself, which is a strictly larger finding
# than brintos/linux-in-the-browser#152 and must not be filed as that issue.
#
# The x86_64 control for all of them (same source, same 24x80 pty): xterm ->
# alternate-screen enter, ESC[J and ESC[7m all present; linux -> ESC[J and ESC[7m
# present, no alternate-screen enter. The entry FILES are not the same on the two
# arms and must not be assumed to be -- see mg/ti-xterm-smcup.
# smcup, with the SPELLING deliberately not pinned. This image's xterm entry is
# ncurses 6.4's own, whose enter_ca_mode is the X11R6-vintage `\E7\E[?47h` (save
# cursor, then the 47 alternate screen); a Debian host's `xterm` resolves instead
# to the modern `\E[?1049h\E[22;0;0t`. Both are correct alternate-screen entries
# and xterm.js honours both, so what is asserted is that mg emitted THE ENTRY'S
# string — pinning the control host's bytes measured RED here against a paint that
# was doing exactly the right thing, which is the mistake this comment exists to
# stop the next reader repeating.
if paint mg-xterm "$esc[?1049h" || paint mg-xterm "$esc[?47h"; then
  bst_ok mg/ti-xterm-smcup
else
  bst_notok mg/ti-xterm-smcup "TERM=xterm paint carries no alternate-screen enter (neither ESC[?1049h nor ESC[?47h) — enter_ca_mode was not read from the entry"
fi
pcase mg/ti-xterm-clear 1 mg-xterm "$esc[J" \
  "TERM=xterm paint carries no ESC[J — clr_eos was not read from the entry"
pcase mg/ti-xterm-standout 1 mg-xterm "$esc[7m" \
  "TERM=xterm paint carries no ESC[7m — the standout pair was not read from the entry"

# smkx, and it is a PRECONDITION of mg/arrow-decoded below rather than a decoration.
# mg puts the terminal into application-cursor mode at startup, and only then does
# Down arrive as ESC O B, which is what the payload sends. If this goes red the
# arrow case is measuring a sequence mg never asked for, so read the two together.
pcase mg/ti-xterm-smkx 1 mg-xterm "$esc[?1h" \
  "TERM=xterm paint carries no ESC[?1h — keypad_xmit was not read, so Down is not ESC O B"

# THE DIFFERENTIAL, which is what separates reading the database from making an
# ANSI guess: the linux entry defines no alternate screen, so mg must NOT emit
# smcup under it while still clearing and still painting the mode line in reverse.
# A build that had fallen back to a built-in guess would paint the two alike.
# ...and the linux entry defines NO enter_ca_mode at all, so its paint must carry
# neither spelling. Both are rejected rather than just the modern one: a paint
# carrying the OTHER spelling would be mg reusing xterm's capability under a
# terminal that does not define it, which is exactly the failure this case exists
# to catch and is invisible to a check for one string.
if paint mg-linux "$esc[?1049h" || paint mg-linux "$esc[?47h"; then
  bst_notok mg/ti-linux-no-smcup "TERM=linux paint carries an alternate-screen enter — the linux entry defines none, so the lookup was not per \$TERM"
else
  bst_ok mg/ti-linux-no-smcup
fi
pcase mg/ti-linux-clear 1 mg-linux "$esc[J" \
  "TERM=linux paint carries no ESC[J — clr_eos was not read from the linux entry"
pcase mg/ti-linux-standout 1 mg-linux "$esc[7m" \
  "TERM=linux paint carries no ESC[7m — standout was not read from the linux entry"

# The mode line is mg's own composition over those capabilities, and it carries
# the buffer state in its first three columns: `--` clean, `**` modified, `%%`
# read-only. Asserted on the read-only paint because that is the one a WRITE
# cannot produce by accident.
pcase mg/modeline-name 1 mg-xterm "Mg: " \
  "the first paint has no mode line — the screen was never composed"

# --- what actually reached the disk (the verdicts that count) ----------------
# S1: two lines typed at the end of an existing buffer and saved through ^X^S,
# in order, with the original line kept.
check_out mg/typed-orig   "hello world"    sh -c "cat '$work/typed.txt'"
check_out mg/typed-first  "hello from mg"  sh -c "cat '$work/typed.txt'"
check_out mg/typed-second "second line"    sh -c "cat '$work/typed.txt'"
check_eq  mg/typed-lines  3 "$(wc -l < "$work/typed.txt" 2>/dev/null | tr -d ' ')"

# mg backs an existing file up to <name>~ the first time it saves it. That is a
# create+write pair on the virtiofs root performed by the application rather than
# by the shell, and its CONTENT must be the file as it was before the edit.
check    mg/typed-backup      sh -c "[ -f '$work/typed.txt~' ]"
check_eq mg/typed-backup-body "hello world" "$(cat "$work/typed.txt~" 2>/dev/null)"

# S2: ^K^K on line 1 removed exactly that line and left the rest intact.
check_eq mg/cut-lines 2 "$(wc -l < "$work/cut.txt" 2>/dev/null | tr -d ' ')"
if grep -q '^alpha$' "$work/cut.txt" 2>/dev/null; then
  bst_notok mg/cut-removed "alpha still present after ^K^K + ^X^S"
else
  bst_ok mg/cut-removed
fi
check_out mg/cut-kept "charlie" sh -c "cat '$work/cut.txt'"

# S3: THE ARROW VERDICT. Down (ESC O B — see mg/ti-xterm-smkx) then ^K^K must take
# line 2. alpha kept + charlie kept + bravo gone == the three bytes decoded as one
# key. bravo present with alpha gone would mean the sequence never assembled and
# the cursor stayed on line 1; a literal "OB" in the file would mean the tail was
# inserted as ordinary text instead.
check_eq mg/arrow-lines 2 "$(wc -l < "$work/arrow.txt" 2>/dev/null | tr -d ' ')"
if grep -q '^bravo$' "$work/arrow.txt" 2>/dev/null; then
  bst_notok mg/arrow-decoded "bravo survived: Down (ESC [ B) did not move the cursor to line 2"
else
  bst_ok mg/arrow-decoded
fi
check_out mg/arrow-kept-first "alpha"   sh -c "cat '$work/arrow.txt'"
check_out mg/arrow-kept-last  "charlie" sh -c "cat '$work/arrow.txt'"
if grep -q 'OB' "$work/arrow.txt" 2>/dev/null; then
  bst_notok mg/arrow-not-literal "the escape sequence was inserted as literal text"
else
  bst_ok mg/arrow-not-literal
fi

# S4: ^S incremental search positioned the cursor on the third line, so the ^K^K
# that followed took charlie and not line 1. A search that silently failed leaves
# alpha gone instead, which is why both ends are asserted.
if grep -q '^charlie$' "$work/find.txt" 2>/dev/null; then
  bst_notok mg/find-positioned "charlie survived: ^S did not move the cursor to the match"
else
  bst_ok mg/find-positioned
fi
check_out mg/find-kept-first "alpha" sh -c "cat '$work/find.txt'"
check_out mg/find-kept-last  "delta" sh -c "cat '$work/find.txt'"
check_eq  mg/find-lines 3 "$(wc -l < "$work/find.txt" 2>/dev/null | tr -d ' ')"

# S5: M-x replace-string replaced the one occurrence and nothing else. The
# ESC-prefix decode is the point; the replacement is how it is observed.
check_out mg/repl-done "BRAVO" sh -c "cat '$work/repl.txt'"
if grep -q '^bravo$' "$work/repl.txt" 2>/dev/null; then
  bst_notok mg/repl-replaced "bravo survived M-x replace-string"
else
  bst_ok mg/repl-replaced
fi
check_out mg/repl-kept-first "alpha"   sh -c "cat '$work/repl.txt'"
check_out mg/repl-kept-last  "charlie" sh -c "cat '$work/repl.txt'"

# S6: the answered newline prompt. 20 bytes = "no trailing newline" + the \n mg
# added on `y`. Pinned as an exact byte count so that mg quietly adding one
# WITHOUT asking -- which is what nano does -- would be a red rather than a match.
check_eq mg/nonl-bytes 20 "$(wc -c < "$work/nonl.txt" 2>/dev/null | tr -d ' ')"
check_eq mg/nonl-lines  1 "$(wc -l < "$work/nonl.txt" 2>/dev/null | tr -d ' ')"

# S7: -R refused the keystrokes at the buffer as well as on the echo line. The
# file must be byte-identical and must have acquired no backup, since mg only
# writes one when it writes the file.
check_eq mg/ro-unchanged "alpha bravo charlie" "$(tr '\n' ' ' < "$work/ro.txt" 2>/dev/null | sed 's/ $//')"
if [ -e "$work/ro.txt~" ]; then
  bst_notok mg/ro-nobackup "mg wrote a backup for a file it was told to open read-only"
else
  bst_ok mg/ro-nobackup
fi

# S8: answering n to "Missing directory, create?" left the tree untouched. mg
# offering to mkdir the parent is a filesystem write the editor performs itself,
# so declining it has to be observable as an absence.
if [ -e "$work/nodir" ]; then
  bst_notok mg/nodir-declined "mg created $work/nodir after the prompt was answered n"
else
  bst_ok mg/nodir-declined
fi

# S9: UTF-8 ROUND TRIP. mg is byte-oriented -- it has no Unicode tables of its own,
# unlike joe -- so a load+save must return the buffer unchanged rather than
# re-encoded. 2-, 3- and 4-byte sequences together.
check mg/utf8-roundtrip sh -c "cmp -s '$work/utf8.txt' '$work/utf8.want'"
check_eq mg/utf8-bytes 25 "$(wc -c < "$work/utf8.txt" 2>/dev/null | tr -d ' ')"

rm -rf "$work"