#!/usr/bin/env bash
set -euo pipefail

SCRIPT_DIR=$(cd -- "$(dirname -- "$0")" && pwd)
START="$SCRIPT_DIR/start-agent-session.sh"
INTERACTION_START="$SCRIPT_DIR/start-interaction-service.sh"
ROOT=$(mktemp -d)
FAKE_BIN=$(mktemp -d)
TMUX_CALLS=$(mktemp)
trap 'rm -rf "$ROOT" "$FAKE_BIN" "$TMUX_CALLS"' EXIT

fail() {
  echo "FAIL: $*" >&2
  exit 1
}

cat > "$FAKE_BIN/tmux" <<'SHIM'
#!/usr/bin/env bash
set -euo pipefail
printf '%s\0' "$@" >> "${MOSAIC_TEST_TMUX_CALLS:?}"
args=("$@")
index=0
if [ "${args[0]:-}" = -L ]; then index=2; fi
case "${args[$index]:-}" in
  has-session)
    for argument in "${args[@]}"; do
      [ "$argument" = '=_holder:0.0' ] && exit 0
    done
    exit 1
    ;;
  show-environment)
    printf '%s\n' \
      "HOME=${MOSAIC_TEST_HOME:?}" \
      'PATH=/usr/bin:/bin' \
      "PWD=${MOSAIC_TEST_HOME:?}" \
      "MOSAIC_FLEET_OWNER=${MOSAIC_TEST_FLEET_OWNER:?}" \
      'MOSAIC_TMUX_HOLDER=_holder' \
      'MOSAIC_TMUX_SOCKET=mosaic-test'
    exit 0
    ;;
  list-panes) printf '%s\n' "${MOSAIC_TEST_PANE_PID:-}"; exit 0 ;;
  new-session)
    if [ "${MOSAIC_TEST_EXECUTE_PANE:-}" = 1 ]; then
      for ((index = 0; index < ${#args[@]}; index++)); do
        if [ "${args[$index]}" = /usr/bin/env ]; then
          "${args[@]:$index}"
          break
        fi
      done
    fi
    exit 0
    ;;
  *) exit 0 ;;
esac
SHIM
chmod +x "$FAKE_BIN/tmux"

cat > "$FAKE_BIN/mosaic" <<'SHIM'
#!/usr/bin/env bash
set -euo pipefail
env -0 > "${MOSAIC_HOME:?}/fleet/pane-environment"
SHIM
chmod +x "$FAKE_BIN/mosaic"

write_generated() {
  local home="$1"
  local agent="$2"
  mkdir -p "$home/fleet/agents" "$home/fleet/run"
  chmod 700 "$home" "$home/fleet" "$home/fleet/agents" "$home/fleet/run"
  printf '123e4567-e89b-12d3-a456-426614174000\n' > "$home/fleet/run/holder-owner"
  chmod 600 "$home/fleet/run/holder-owner"
  cat > "$home/fleet/agents/$agent.env.generated" <<EOF
MOSAIC_AGENT_NAME=$agent
MOSAIC_AGENT_CLASS=code
MOSAIC_AGENT_RUNTIME=pi
MOSAIC_AGENT_MODEL=openai-codex/gpt-5.6-sol
MOSAIC_AGENT_REASONING=high
MOSAIC_AGENT_TOOL_POLICY=code
MOSAIC_AGENT_WORKDIR=$home/work
MOSAIC_TMUX_SOCKET=mosaic-test
EOF
  chmod 600 "$home/fleet/agents/$agent.env.generated"
  mkdir -p "$home/work"
}

run_start() {
  local home="$1"
  local agent="$2"
  HOME="$home" PATH="$FAKE_BIN:$PATH" MOSAIC_TEST_TMUX_CALLS="$TMUX_CALLS" \
    MOSAIC_TEST_PANE_PID="${MOSAIC_TEST_PANE_PID:-}" \
    MOSAIC_TEST_HOME="$home" \
    MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
    MOSAIC_HOME="$home" "$START" "$agent"
}

# Valid generated data launches only the fixed runtime argument array. It never
# reads an agent-command string or constructs a bash -c pane payload.
HOME_VALID="$ROOT/valid"
AGENT_VALID="coder0"
write_generated "$HOME_VALID" "$AGENT_VALID"
run_start "$HOME_VALID" "$AGENT_VALID"
valid_args=$(tr '\0' '\n' < "$TMUX_CALLS")
echo "$valid_args" | grep -qF new-session || fail "valid generated projection did not reach tmux"
echo "$valid_args" | grep -qF 'mosaic' || fail "fixed mosaic launcher command missing"
echo "$valid_args" | grep -qF 'yolo' || fail "fixed yolo launcher command missing"
echo "$valid_args" | grep -qF 'pi' || fail "roster runtime missing"
if echo "$valid_args" | grep -qF 'bash -c'; then
  fail "launcher constructed a shell command payload"
fi

# The pane must start through an absolute clean-environment boundary. Its
# runtime command remains an argv vector, but no holder/session environment
# control variable can pass through the pane command.
echo "$valid_args" | grep -qxF '/usr/bin/env' || fail "pane does not use absolute env"
echo "$valid_args" | grep -qxF -- '-i' || fail "pane environment is not cleared"

# The generated-file parent is a security boundary too: even a private regular
# file is untrusted if its parent can be replaced or written by another user.
# Validation must happen before fake tmux receives even a has-session call.
: > "$TMUX_CALLS"
HOME_UNSAFE_PARENT="$ROOT/unsafe-parent"
write_generated "$HOME_UNSAFE_PARENT" "coder-parent"
chmod 777 "$HOME_UNSAFE_PARENT/fleet/agents"
if output=$(run_start "$HOME_UNSAFE_PARENT" coder-parent 2>&1); then
  fail "generated file under a world-writable parent was accepted"
fi
[ ! -s "$TMUX_CALLS" ] || fail "tmux ran before unsafe parent rejection"
echo "$output" | grep -qF 'code=unsafe-permissions' || fail "unsafe parent diagnostic missing"

: > "$TMUX_CALLS"
HOME_SYMLINK_PARENT="$ROOT/symlink-parent"
write_generated "$HOME_SYMLINK_PARENT" "coder-symlink-parent"
mv "$HOME_SYMLINK_PARENT/fleet/agents" "$HOME_SYMLINK_PARENT/private-agents"
ln -s "$HOME_SYMLINK_PARENT/private-agents" "$HOME_SYMLINK_PARENT/fleet/agents"
if output=$(run_start "$HOME_SYMLINK_PARENT" coder-symlink-parent 2>&1); then
  fail "generated file under a symlinked parent was accepted"
fi
[ ! -s "$TMUX_CALLS" ] || fail "tmux ran before symlinked parent rejection"
echo "$output" | grep -qF 'code=unsafe-directory' || fail "symlinked parent diagnostic missing"

# Every managed ancestor is a boundary: MOSAIC_HOME, fleet, and agents. A
# symlink or group/world-writable ancestor must fail before environment parsing,
# workdir creation, or tmux effects. The malformed local input proves parsing
# was not reached when the ancestor rejection is reported.
assert_managed_ancestor_rejected() {
  local ancestor="$1"
  local hazard="$2"
  local home="$ROOT/managed-${ancestor//\//-}-${hazard}"
  local agent="coder-managed-${ancestor//\//-}-${hazard}"
  local node
  write_generated "$home" "$agent"
  printf 'MOSAIC_AGENT_COMMAND=must-not-be-parsed\n' > "$home/fleet/agents/$agent.env.local"
  chmod 600 "$home/fleet/agents/$agent.env.local"
  rm -rf "$home/work"

  case "$ancestor" in
    MOSAIC_HOME) node="$home" ;;
    MOSAIC_HOME/fleet) node="$home/fleet" ;;
    MOSAIC_HOME/fleet/agents) node="$home/fleet/agents" ;;
    *) fail "unknown managed ancestor: $ancestor" ;;
  esac

  if [ "$hazard" = symlink ]; then
    local target="${node}-target"
    mv "$node" "$target"
    ln -s "$target" "$node"
  else
    chmod 777 "$node"
  fi

  : > "$TMUX_CALLS"
  if output=$(run_start "$home" "$agent" 2>&1); then
    fail "${hazard} $ancestor was accepted"
  fi
  [ ! -s "$TMUX_CALLS" ] || fail "tmux ran before $hazard $ancestor rejection"
  [ ! -e "$home/work" ] || fail "workdir was created before $hazard $ancestor rejection"
  echo "$output" | grep -qF "code=unsafe-" || fail "managed ancestor diagnostic missing"
  if echo "$output" | grep -qF 'key=MOSAIC_AGENT_COMMAND'; then
    fail "environment parsing ran before $hazard $ancestor rejection"
  fi
}

for managed_ancestor in MOSAIC_HOME MOSAIC_HOME/fleet MOSAIC_HOME/fleet/agents; do
  assert_managed_ancestor_rejected "$managed_ancestor" symlink
  assert_managed_ancestor_rejected "$managed_ancestor" group-world-writable
done

# A local file cannot shadow any roster-derived generated key. Validation must
# happen before fake tmux receives even a has-session call.
: > "$TMUX_CALLS"
HOME_SHADOW="$ROOT/shadow"
write_generated "$HOME_SHADOW" "coder1"
printf 'MOSAIC_AGENT_RUNTIME=codex\n' > "$HOME_SHADOW/fleet/agents/coder1.env.local"
chmod 600 "$HOME_SHADOW/fleet/agents/coder1.env.local"
if output=$(run_start "$HOME_SHADOW" coder1 2>&1); then
  fail "generated-key shadow was accepted"
fi
[ ! -s "$TMUX_CALLS" ] || fail "tmux ran before generated-key shadow rejection"
echo "$output" | grep -qF 'key=MOSAIC_AGENT_RUNTIME' || fail "shadow diagnostic omitted key"
echo "$output" | grep -qF 'sha256=' || fail "shadow diagnostic omitted hash"
if echo "$output" | grep -qF 'codex'; then
  fail "shadow diagnostic leaked value"
fi

# Arbitrary command compatibility is quarantined/rejected as data. Diagnostics
# may name the key and hash but must never echo the privileged command text.
: > "$TMUX_CALLS"
HOME_COMMAND="$ROOT/command"
write_generated "$HOME_COMMAND" "coder2"
COMMAND_VALUE='mosaic yolo codex --dangerous'
printf 'MOSAIC_AGENT_COMMAND=%s\n' "$COMMAND_VALUE" > "$HOME_COMMAND/fleet/agents/coder2.env.local"
chmod 600 "$HOME_COMMAND/fleet/agents/coder2.env.local"
if output=$(run_start "$HOME_COMMAND" coder2 2>&1); then
  fail "arbitrary command override was accepted"
fi
[ ! -s "$TMUX_CALLS" ] || fail "tmux ran before command rejection"
echo "$output" | grep -qF 'key=MOSAIC_AGENT_COMMAND' || fail "command diagnostic omitted key"
echo "$output" | grep -qF 'sha256=' || fail "command diagnostic omitted hash"
if echo "$output" | grep -qF "$COMMAND_VALUE"; then
  fail "command diagnostic leaked command value"
fi

# Group/world-readable local input is not trusted even when its syntax is safe.
: > "$TMUX_CALLS"
HOME_PERMS="$ROOT/perms"
write_generated "$HOME_PERMS" "coder3"
printf 'MOSAIC_RUNTIME_BIN=/opt/mosaic/bin\n' > "$HOME_PERMS/fleet/agents/coder3.env.local"
chmod 644 "$HOME_PERMS/fleet/agents/coder3.env.local"
if output=$(run_start "$HOME_PERMS" coder3 2>&1); then
  fail "world-readable local input was accepted"
fi
[ ! -s "$TMUX_CALLS" ] || fail "tmux ran before permissions rejection"
echo "$output" | grep -qF 'code=unsafe-permissions' || fail "permission diagnostic missing"

# A unit/holder-like clean bootstrap must yield a pane with trusted HOME and
# computed PATH only. The pane command itself must not carry loader, shell
# control, arbitrary sentinel, or stale bootstrap variables.
: > "$TMUX_CALLS"
HOME_PANE_BOUNDARY="$ROOT/pane-boundary/.config/mosaic"
write_generated "$HOME_PANE_BOUNDARY" "coder-pane-boundary"
PANE_TRUSTED_HOME="${HOME_PANE_BOUNDARY%/.config/mosaic}"
PANE_STALE_HOME="$ROOT/stale-home"
PANE_STALE_PATH="$ROOT/stale-bin"
PANE_BASH_ENV="$ROOT/pane-boundary.bash-env"
printf 'MOSAIC_RUNTIME_BIN=%s\n' "$FAKE_BIN" > \
  "$HOME_PANE_BOUNDARY/fleet/agents/coder-pane-boundary.env.local"
chmod 600 "$HOME_PANE_BOUNDARY/fleet/agents/coder-pane-boundary.env.local"
LD_PRELOAD='/not/loaded/by-clean-bootstrap.so' \
BASH_ENV="$PANE_BASH_ENV" \
MOSAIC_UNTRUSTED_SENTINEL='must-not-reach-pane' \
HOME="$PANE_STALE_HOME" \
PATH="$PANE_STALE_PATH" \
  /usr/bin/env -i \
    "HOME=$PANE_TRUSTED_HOME" \
    "PATH=$FAKE_BIN:/usr/bin:/bin" \
    "MOSAIC_HOME=$HOME_PANE_BOUNDARY" \
    "MOSAIC_TEST_TMUX_CALLS=$TMUX_CALLS" \
    "MOSAIC_TEST_HOME=$PANE_TRUSTED_HOME" \
    MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
    MOSAIC_TEST_EXECUTE_PANE=1 \
    "$START" coder-pane-boundary
pane_args=$(tr '\0' '\n' < "$TMUX_CALLS")
echo "$pane_args" | grep -qxF "HOME=$PANE_TRUSTED_HOME" || \
  fail "pane did not restore trusted HOME"
echo "$pane_args" | grep -qF "HOME=$PANE_STALE_HOME" && \
  fail "pane inherited stale HOME"
echo "$pane_args" | grep -qF "$PANE_STALE_PATH" && fail "pane inherited stale PATH"
for blocked in LD_PRELOAD= BASH_ENV= MOSAIC_UNTRUSTED_SENTINEL=; do
  echo "$pane_args" | grep -qF "$blocked" && fail "pane inherited $blocked"
done

after_pane_env=$(printf '%s\n' "$pane_args" | grep -n -m1 -F '/usr/bin/env' | cut -d: -f1)
[ -n "$after_pane_env" ] || fail "pane command did not use absolute env"
printf '%s\n' "$pane_args" | tail -n +"$after_pane_env" | grep -qxF -- '-i' || \
  fail "pane command did not clear its environment"
pane_environment=$(tr '\0' '\n' < "$HOME_PANE_BOUNDARY/fleet/pane-environment")
echo "$pane_environment" | grep -qxF "HOME=$PANE_TRUSTED_HOME" || \
  fail "runtime pane did not receive trusted HOME"
echo "$pane_environment" | grep -qF "$PANE_STALE_PATH" && fail "runtime pane received stale PATH"
for blocked in LD_PRELOAD= BASH_ENV= MOSAIC_UNTRUSTED_SENTINEL=; do
  echo "$pane_environment" | grep -qF "$blocked" && fail "runtime pane received $blocked"
done

write_interaction_generated() {
  local home="$1"
  local agent="$2"
  mkdir -p "$home/fleet/agents" "$home/fleet/run" "$home/work"
  chmod 700 "$home" "$home/fleet" "$home/fleet/agents" "$home/fleet/run"
  printf '123e4567-e89b-12d3-a456-426614174000\n' > "$home/fleet/run/holder-owner"
  chmod 600 "$home/fleet/run/holder-owner"
  cat > "$home/fleet/agents/$agent.env.generated" <<EOF
MOSAIC_AGENT_NAME=$agent
MOSAIC_AGENT_CLASS=operator-interaction
MOSAIC_AGENT_RUNTIME=pi
MOSAIC_AGENT_MODEL=openai/gpt-5.6-sol
MOSAIC_AGENT_REASONING=high
MOSAIC_AGENT_TOOL_POLICY=operator-interaction
MOSAIC_AGENT_WORKDIR=$home/work
MOSAIC_TMUX_SOCKET=mosaic-test
EOF
  chmod 600 "$home/fleet/agents/$agent.env.generated"
}

run_interaction() {
  local home="$1"
  local agent="$2"
  HOME="$home" PATH="$FAKE_BIN:$PATH" MOSAIC_TEST_TMUX_CALLS="$TMUX_CALLS" \
    MOSAIC_TEST_HOME="$home" \
    MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
    MOSAIC_HOME="$home" "$INTERACTION_START" "$agent"
}

write_heartbeat_local() {
  local home="$1"
  local agent="$2"
  mkdir -p "$home/run"
  cat > "$home/fleet/agents/$agent.env.local" <<EOF
MOSAIC_HEARTBEAT_RUN_DIR=$home/run
MOSAIC_HEARTBEAT_INTERVAL=1
EOF
  chmod 600 "$home/fleet/agents/$agent.env.local"
}

wait_for_sidecar_status() {
  local file="$1"
  for _retry in $(seq 1 30); do
    grep -qF 'status=ok' "$file" 2>/dev/null && return 0
    sleep 0.1
  done
  fail "heartbeat sidecar did not resume after native marker became stale or absent"
}

# A fresh Pi-native marker is authoritative: the shell sidecar may start but
# must not overwrite Pi's busy/ok/model heartbeat. It must resume only when
# the marker is stale or absent.
HOME_NATIVE_FRESH="$ROOT/native-fresh"
write_generated "$HOME_NATIVE_FRESH" "coder-native-fresh"
write_heartbeat_local "$HOME_NATIVE_FRESH" "coder-native-fresh"
FRESH_HB="$HOME_NATIVE_FRESH/run/coder-native-fresh.hb"
printf 'ts=native\npid=1\nstatus=busy\nmodel=authoritative-model\n' > "$FRESH_HB"
touch "$FRESH_HB.native"
MOSAIC_TEST_PANE_PID=$$ run_start "$HOME_NATIVE_FRESH" coder-native-fresh
sleep 0.3
fresh_content=$(cat "$FRESH_HB")
[ "$fresh_content" = 'ts=native
pid=1
status=busy
model=authoritative-model' ] || fail "fresh native heartbeat was overwritten"

HOME_NATIVE_STALE="$ROOT/native-stale"
write_generated "$HOME_NATIVE_STALE" "coder-native-stale"
write_heartbeat_local "$HOME_NATIVE_STALE" "coder-native-stale"
STALE_HB="$HOME_NATIVE_STALE/run/coder-native-stale.hb"
printf 'ts=native\npid=1\nstatus=busy\nmodel=stale-model\n' > "$STALE_HB"
touch -d '10 seconds ago' "$STALE_HB.native"
MOSAIC_TEST_PANE_PID=$$ run_start "$HOME_NATIVE_STALE" coder-native-stale
wait_for_sidecar_status "$STALE_HB"

HOME_NATIVE_ABSENT="$ROOT/native-absent"
write_generated "$HOME_NATIVE_ABSENT" "coder-native-absent"
write_heartbeat_local "$HOME_NATIVE_ABSENT" "coder-native-absent"
ABSENT_HB="$HOME_NATIVE_ABSENT/run/coder-native-absent.hb"
printf 'ts=native\npid=1\nstatus=busy\nmodel=absent-model\n' > "$ABSENT_HB"
MOSAIC_TEST_PANE_PID=$$ run_start "$HOME_NATIVE_ABSENT" coder-native-absent
wait_for_sidecar_status "$ABSENT_HB"

# The interaction wrapper delegates to the shared strict parser before applying
# its pinned policy, so malformed projection data wins over profile diagnostics.
: > "$TMUX_CALLS"
HOME_INTERACTION_MALFORMED="$ROOT/interaction-malformed"
write_interaction_generated "$HOME_INTERACTION_MALFORMED" "interaction-malformed"
printf 'UNTRUSTED_BOOTSTRAP=value\n' >> "$HOME_INTERACTION_MALFORMED/fleet/agents/interaction-malformed.env.generated"
if output=$(run_interaction "$HOME_INTERACTION_MALFORMED" interaction-malformed 2>&1); then
  fail "interaction wrapper accepted malformed generated data"
fi
[ ! -s "$TMUX_CALLS" ] || fail "tmux ran before interaction strict-parser rejection"
echo "$output" | grep -qF 'code=unknown-key' || fail "interaction did not use shared strict parser first"

# A syntactically valid but policy-incompatible projection reaches the pinned
# interaction policy check only after strict parsing and never starts tmux.
: > "$TMUX_CALLS"
HOME_INTERACTION_POLICY="$ROOT/interaction-policy"
write_interaction_generated "$HOME_INTERACTION_POLICY" "interaction-policy"
perl -0pi -e 's/MOSAIC_AGENT_RUNTIME=pi/MOSAIC_AGENT_RUNTIME=codex/' \
  "$HOME_INTERACTION_POLICY/fleet/agents/interaction-policy.env.generated"
if output=$(run_interaction "$HOME_INTERACTION_POLICY" interaction-policy 2>&1); then
  fail "interaction wrapper accepted a policy-incompatible projection"
fi
interaction_policy_args=$(tr '\0' '\n' < "$TMUX_CALLS")
echo "$interaction_policy_args" | grep -qF 'new-session' && \
  fail "interaction pinned-policy rejection created a tmux session"
echo "$output" | grep -qF 'operator interaction service requires runtime pi' || \
  fail "interaction pinned-policy check did not follow strict parsing"

# Exact stop derives the socket exclusively from the validated generated
# projection and ignores an ambient socket supplied by the caller.
: > "$TMUX_CALLS"
HOME_STOP="$ROOT/stop"
write_generated "$HOME_STOP" "coder-stop"
HOME="$HOME_STOP" PATH="$FAKE_BIN:$PATH" MOSAIC_TEST_TMUX_CALLS="$TMUX_CALLS" \
  MOSAIC_TEST_HOME="$HOME_STOP" \
  MOSAIC_TEST_FLEET_OWNER=123e4567-e89b-12d3-a456-426614174000 \
  MOSAIC_HOME="$HOME_STOP" MOSAIC_TMUX_SOCKET=ambient-socket "$START" --stop coder-stop
stop_args=$(tr '\0' '\n' < "$TMUX_CALLS")
echo "$stop_args" | grep -qxF 'mosaic-test' || fail "exact stop did not use the validated generated socket"
echo "$stop_args" | grep -qxF 'kill-session' || fail "exact stop did not request session termination"
echo "$stop_args" | grep -qxF '=coder-stop' || fail "exact stop did not exact-match the generated agent name"
if echo "$stop_args" | grep -qF 'ambient-socket'; then
  fail "exact stop trusted an ambient socket"
fi

echo 'ok - start-agent-session generated environment boundary'