#!/usr/bin/env bash

# The launcher at the bottom of the escalation ladder.
#
# Every rung -- the crash toast, the failed reload, a red health check,
# `panama diagnose` -- ends at bin/panama-agent, which turns two settings into
# one terminal running one agent. It is the single place where the ladder can
# quietly become a no-op, or launch the wrong thing, or lose the prompt it was
# handed, so it is the single place worth pinning.
#
# What must hold:
#
#   1. "none" is silent. No agent chosen is the shipped state, not an error.
#      A rung that shouted about it is a rung that gets switched off, and a
#      missing settings file means the same thing as "none".
#   2. The argv per agent is the one the installed binaries actually accept.
#      These flags move between releases; the table in panama-agent was read off
#      `claude --help` and `codex --help`, and this pins the shape of it.
#   3. agentAutoApprove off means no mode flag at all. The agent's own default
#      is a choice the user already made.
#   4. The prompt is ONE argv element. Crash and diagnose prompts are multi-line
#      paragraphs; a prompt that arrives as forty words is forty words of
#      nothing.
#   5. The working directory is the checkout. The skills the prompts name, the
#      repository being asked about, and .claude/settings.json's pre-approved
#      read-only diagnostics all live here and nowhere else.
#   6. panama-agent-crash carries all four coredump facts and the absolute path
#      to the skill. The path is what makes the ladder work for an agent whose
#      harness has no skill mechanism.
#
# Hermetic on purpose: kitty, claude, codex, setsid and coredumpctl are all
# stubbed onto PATH and the settings file is fabricated, so no agent is ever
# launched and no window is ever opened. This is NOT in tests/desktop-hijacking
# for exactly that reason -- it must stay runnable mid-session.

set -uo pipefail

repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
launcher="$repo_dir/bin/panama-agent"
crash="$repo_dir/bin/panama-agent-crash"
reload="$repo_dir/bin/panama-agent-reload"

findings=()
note() { findings+=("$1"); }

for script in "$launcher" "$crash" "$reload"; do
    [[ -x "$script" ]] || { printf 'panama agent contract: %s is not executable\n' "$script" >&2; exit 1; }
done

work="$(mktemp -d)"
trap 'rm -rf "$work"' EXIT
stub="$work/bin"
mkdir -p "$stub"
settings="$work/settings.json"

# The terminal, replaced by something that records what it was asked to run.
# NUL-separated, because the prompts are multi-line and any line-oriented record
# would lose exactly the property this is here to check.
cat >"$stub/kitty" <<STUB
#!/usr/bin/env bash
printf '%s' "\$PWD" >"$work/cwd"
printf '%s\0' "\$@" >"$work/argv"
STUB

# setsid is stubbed rather than real so the launch is synchronous and there is
# no race between the detached child writing and this reading it.
cat >"$stub/setsid" <<STUB
#!/usr/bin/env bash
: >"$work/setsid-used"
exec "\$@"
STUB

# Present so panama-agent's "is it installed" check passes. Reaching one of
# these means the terminal stub was bypassed, which is itself a failure.
for agent in claude codex; do
    cat >"$stub/$agent" <<STUB
#!/usr/bin/env bash
: >"$work/agent-actually-ran"
STUB
done

# A hand-run PID has no core here; the real one would be a slow lookup against
# this machine's journal.
cat >"$stub/coredumpctl" <<'STUB'
#!/usr/bin/env bash
exit 1
STUB

# The rungs that quote the journal get a deliberately enormous one. journalctl
# counts entries, not lines, and a real one on this machine answered a
# thirty-entry request with 2,430 lines and a quarter of a megabyte of
# backtrace -- which exec rejects outright, because a single argv element is
# capped at 128KB. The prompt builders have to bound what they quote, and this
# is what proves they do.
cat >"$stub/journalctl" <<'STUB'
#!/usr/bin/env bash
line="quickshell: QML Item: Cannot assign to non-existent property$(printf '%0.sx' {1..500})"
for _ in {1..4000}; do printf '%s\n' "$line"; done
STUB

chmod +x "$stub"/*

# Runs the launcher hermetically and returns its exit status. argv/cwd records
# from the previous run are cleared first, so "was not launched" is a missing
# file rather than a stale one.
launch() {
    rm -f "$work/argv" "$work/cwd" "$work/setsid-used" "$work/agent-actually-ran"
    PATH="$stub:/usr/bin:/bin" \
        PANAMA_PATH="$repo_dir" \
        PANAMA_AGENT_SETTINGS="$settings" \
        "$@" >"$work/stdout" 2>"$work/stderr"
}

# The recorded argv, as an array.
recorded_argv() {
    argv=()
    [[ -s "$work/argv" ]] || return 1
    mapfile -d '' -t argv <"$work/argv"
    return 0
}

# The argv as one string with a separator no prompt contains, so a whole
# element can be matched without a line-oriented search.
argv_joined() {
    local IFS=$'\x1f'
    printf '%s' "${argv[*]}"
}

# Just the command kitty was told to run: everything after -e, with the
# terminal's own flags dropped. Split out because the agent's argv is what these
# checks are about, and matching it inside the whole line means writing patterns
# that would also match a --title.
agent_command() {
    agent_argv=()
    local element seen=0
    for element in "${argv[@]}"; do
        if (( seen )); then
            agent_argv+=("$element")
        elif [[ "$element" == "-e" ]]; then
            seen=1
        fi
    done
    (( ${#agent_argv[@]} > 0 ))
}

# The agent argv from element 1 on, joined -- the flags, without the resolved
# binary path, which differs per machine and is checked separately.
agent_flags() {
    local IFS=$'\x1f'
    printf '%s' "${agent_argv[*]:1}"
}

# ── 1. "none" is silent ─────────────────────────────────────────────────────

printf '{"preferredAgent":"none"}\n' >"$settings"
launch "$launcher" --prompt "anything"
status=$?

(( status == 0 )) || note "with no agent chosen panama-agent exited $status; choosing none is not an error"
[[ -s "$work/stdout" ]] && note 'with no agent chosen panama-agent printed to stdout; it is meant to be silent'
[[ -s "$work/stderr" ]] && note "with no agent chosen panama-agent complained: $(head -1 "$work/stderr")"
[[ -e "$work/argv" ]] && note 'with no agent chosen panama-agent still opened a terminal'

# A machine that has never been asked the question answers the same way.
rm -f "$settings"
launch "$launcher" --prompt "anything"
status=$?
(( status == 0 )) || note "with no settings file panama-agent exited $status; the default is none, which is silent"
[[ -e "$work/argv" ]] && note 'with no settings file panama-agent opened a terminal anyway'

# ── 2, 4, 5. Claude, auto-approving ─────────────────────────────────────────

prompt=$'first line\nsecond line with spaces'

printf '{"preferredAgent":"claude","agentAutoApprove":true}\n' >"$settings"
launch "$launcher" --prompt "$prompt"
status=$?

(( status == 0 )) || note "panama-agent exited $status launching claude"
[[ -e "$work/setsid-used" ]] || note 'the launch does not go through setsid, so the agent dies with whatever spawned it'
[[ -e "$work/agent-actually-ran" ]] && note 'the contract reached a real agent binary; it must stop at the terminal stub'

if recorded_argv && agent_command; then
    joined="$(argv_joined)"

    [[ "$joined" == *$'\x1f'"--class"$'\x1f'"panama-agent"* ]] \
        || note 'the terminal is not given the fixed panama-agent window class, so no window rule can find it'
    [[ "$joined" == *"--directory"$'\x1f'"$repo_dir"* ]] \
        || note 'the terminal is not opened in the Panama checkout'

    # The binary is resolved here, not left for kitty to find. The click that
    # reaches this script comes from the shell, whose PATH does not contain
    # ~/.local/bin, and kitty would inherit exactly that PATH.
    [[ "${agent_argv[0]}" == /* ]] \
        || note "the agent is passed to the terminal as '${agent_argv[0]}' rather than a resolved path"
    [[ "${agent_argv[0]}" == */claude ]] \
        || note "the resolved binary is ${agent_argv[0]}, which is not claude"

    [[ "$(agent_flags)" == "--permission-mode"$'\x1f'"auto"$'\x1f'"--"$'\x1f'"$prompt" ]] \
        || note "claude with auto-approve on is launched as: $(agent_flags)"

    # 4. The prompt survives as one element, newlines and all.
    [[ "${argv[-1]}" == "$prompt" ]] \
        || note 'the prompt did not arrive as a single argv element'

    # 5. Not just named as a flag -- actually the working directory.
    [[ "$(cat "$work/cwd" 2>/dev/null)" == "$repo_dir" ]] \
        || note "the agent starts in $(cat "$work/cwd" 2>/dev/null), not in the checkout"
else
    note 'launching claude opened no terminal at all'
fi

# ── 3. Claude, prompting normally ───────────────────────────────────────────

printf '{"preferredAgent":"claude","agentAutoApprove":false}\n' >"$settings"
launch "$launcher" --prompt "$prompt"

if recorded_argv && agent_command; then
    [[ "$(agent_flags)" == *"--permission-mode"* ]] \
        && note 'agentAutoApprove is off and claude was still given a permission mode'
    [[ "$(agent_flags)" == "--"$'\x1f'"$prompt" ]] \
        || note "claude with auto-approve off is launched as: $(agent_flags)"
else
    note 'launching claude with auto-approve off opened no terminal'
fi

# ── 2 & 3. Codex, both ways ─────────────────────────────────────────────────

printf '{"preferredAgent":"codex","agentAutoApprove":true}\n' >"$settings"
launch "$launcher" --prompt "$prompt"

if recorded_argv && agent_command; then
    [[ "${agent_argv[0]}" == */codex ]] \
        || note "the resolved binary is ${agent_argv[0]}, which is not codex"
    [[ "$(agent_flags)" == "--approve-for-me"$'\x1f'"--"$'\x1f'"$prompt" ]] \
        || note "codex with auto-approve on is launched as: $(agent_flags)"
    [[ "${argv[-1]}" == "$prompt" ]] \
        || note 'codex did not receive the prompt as a single argv element'
else
    note 'launching codex opened no terminal'
fi

printf '{"preferredAgent":"codex","agentAutoApprove":false}\n' >"$settings"
launch "$launcher" --prompt "$prompt"

if recorded_argv && agent_command; then
    [[ "$(agent_flags)" == *"--approve-for-me"* ]] \
        && note 'agentAutoApprove is off and codex was still told to approve for itself'
    [[ "$(agent_flags)" == "--"$'\x1f'"$prompt" ]] \
        || note "codex with auto-approve off is launched as: $(agent_flags)"
else
    note 'launching codex with auto-approve off opened no terminal'
fi

# ── An agent installed where only the user's own PATH looks ─────────────────
#
# Both agents install themselves into ~/.local/bin. The rungs are clicked from
# the shell, and systemd starts the shell with a PATH that does not contain it,
# so a launcher that trusted the inherited PATH would report every installed
# agent as missing -- from a detached process, into a stderr nobody reads.

home="$work/home"
mkdir -p "$home/.local/bin" "$work/bin-noagent" "$work/empty"
cp "$stub/kitty" "$stub/setsid" "$work/bin-noagent/"
cp "$stub/claude" "$home/.local/bin/claude"

printf '{"preferredAgent":"claude","agentAutoApprove":true}\n' >"$settings"
rm -f "$work/argv" "$work/cwd"
HOME="$home" PATH="$work/bin-noagent:/usr/bin:/bin" \
    PANAMA_PATH="$repo_dir" PANAMA_AGENT_SETTINGS="$settings" \
    "$launcher" --prompt "$prompt" >"$work/stdout" 2>"$work/stderr"
status=$?
(( status == 0 )) || note "an agent installed in ~/.local/bin was not found: $(head -1 "$work/stderr")"

if recorded_argv && agent_command; then
    [[ "${agent_argv[0]}" == "$home/.local/bin/claude" ]] \
        || note "an agent reachable only through ~/.local/bin resolved to ${agent_argv[0]}"
else
    note 'an agent installed in ~/.local/bin opened no terminal, so every click from the shell would be a dead end'
fi

# ── An agent that is genuinely not installed says so ────────────────────────

rm -f "$work/argv" "$work/cwd"
HOME="$work/empty" PATH="$work/empty:/usr/bin:/bin" \
    PANAMA_PATH="$repo_dir" PANAMA_AGENT_SETTINGS="$settings" \
    "$launcher" --prompt "$prompt" >"$work/stdout" 2>"$work/stderr"
status=$?
(( status != 0 )) || note 'a preferred agent that is not installed exited 0, so the rung failed silently'
grep -qi 'not installed' "$work/stderr" \
    || note 'a missing agent binary produced no explanation naming it'

# ── 6. The crash prompt carries the facts ───────────────────────────────────

printf '{"preferredAgent":"claude","agentAutoApprove":true}\n' >"$settings"
launch "$crash" 4242 panama-test-cra /usr/bin/panama-test-crasher SIGSEGV
status=$?

(( status == 0 )) || note "panama-agent-crash exited $status"
[[ -e "$work/agent-actually-ran" ]] && note 'panama-agent-crash reached a real agent binary'

if recorded_argv; then
    crash_prompt="${argv[-1]}"
    for fact in 4242 panama-test-cra /usr/bin/panama-test-crasher SIGSEGV; do
        [[ "$crash_prompt" == *"$fact"* ]] \
            || note "the crash prompt does not mention $fact, which a diagnosis needs"
    done
    [[ "$crash_prompt" == *"$repo_dir/skills/diagnose-crash/SKILL.md"* ]] \
        || note 'the crash prompt does not give the absolute path to the diagnose-crash skill, so an agent without a skill mechanism has nothing to read'
    [[ -r "$repo_dir/skills/diagnose-crash/SKILL.md" ]] \
        || note 'the path the crash prompt points at does not exist'
else
    note 'panama-agent-crash opened no terminal'
fi

# Something that is not a PID is a usage error, not a prompt about "unknown".
launch "$crash" not-a-pid
status=$?
(( status != 0 )) || note 'panama-agent-crash accepted a non-PID and launched anyway'
[[ -e "$work/argv" ]] && note 'panama-agent-crash launched an agent for a non-PID'

# ── The reload prompt ───────────────────────────────────────────────────────

launch "$reload" "shell.qml:42 Cannot assign to non-existent property"
status=$?
(( status == 0 )) || note "panama-agent-reload exited $status"

if recorded_argv; then
    [[ "${argv[-1]}" == *"Cannot assign to non-existent property"* ]] \
        || note 'the reload prompt does not carry what Quickshell reported'
else
    note 'panama-agent-reload opened no terminal'
fi

launch "$reload"
status=$?
(( status != 0 )) || note 'panama-agent-reload with nothing to report launched an agent anyway'

# ── The by-hand rung ────────────────────────────────────────────────────────
#
# `panama diagnose` quotes the journal too, and quoted the whole of it once:
# exec answered with "Argument list too long" and the rung did nothing at all.
# The health summary here is the real one, which is read-only and takes about a
# second.

launch "$repo_dir/bin/panama" diagnose the bar disappears after unplugging
status=$?
(( status == 0 )) || note "panama diagnose exited $status: $(head -1 "$work/stderr")"

if recorded_argv; then
    diagnose_prompt="${argv[-1]}"
    (( ${#diagnose_prompt} < 131072 )) \
        || note "the diagnose prompt is ${#diagnose_prompt} bytes; one argv element caps at 128KB and exec would refuse it"
    [[ "$diagnose_prompt" == *"the bar disappears after unplugging"* ]] \
        || note 'the diagnose prompt dropped the words the person typed, which are the part no collector reports'
else
    note 'panama diagnose opened no terminal'
fi

if (( ${#findings[@]} > 0 )); then
    printf 'panama agent contract: %d finding(s)\n' "${#findings[@]}" >&2
    printf '  - %s\n' "${findings[@]}" >&2
    exit 1
fi

printf 'panama agent contract: PASS\n'