#!/usr/bin/env bash
# resume_session.sh — resume a stopped session
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
LIB_SH="$(cd "$SCRIPT_DIR/../.." && pwd)/lib.sh"
[ -f "$LIB_SH" ] || LIB_SH="${WORKSPACE_ROOT:-$PWD}/.agents/skills/lib.sh"
source "$LIB_SH"

usage() {
  cat <<EOF
Usage: $0 --workspace <path> --agent <claude|agy|hermes|grok|opencode|codex> --session <name> [options]

Options:
  --herdr-session NAME specify isolated herdr session name (alias: --herdr-server)
  --no-auto-trust      do not answer a start-up directory-trust dialog (default: answer it;
                       other blocking notices are always answered) - same switch as create
  --dry-run            Simulates resume flow (resolves binary, environment) without writing
                       any updates to YAML or DB. Safe to execute inside active write transactions.
EOF
}

WORKSPACE=""
AGENT=""
SESSION_NAME=""
HERDR_SERVER_OPT=""
HERDR_WORKSPACE_OPT=""

DRY_RUN=0
# Issue #24: a resumed CLI shows the same directory-trust dialog as a fresh
# one, so resume takes the same switch as create (MAM_AUTO_TRUST is what
# handle_startup_dialogs reads).
AUTO_TRUST="${MAM_AUTO_TRUST:-1}"  # the environment form of the same switch; a flag wins

while [ $# -gt 0 ]; do
  case "$1" in
    --workspace) WORKSPACE="$2"; shift 2 ;;
    --agent)     AGENT="$2";     shift 2 ;;
    --session)   SESSION_NAME="$2"; shift 2 ;;
    --herdr-session|--herdr-server) HERDR_SERVER_OPT="$2"; shift 2 ;;
    --herdr-workspace) HERDR_WORKSPACE_OPT="$2"; shift 2 ;;
    --auto-trust) AUTO_TRUST=1; shift ;;
    --no-auto-trust) AUTO_TRUST=0; shift ;;
    --dry-run)   DRY_RUN=1; shift ;;
    -h|--help)   usage; exit 0 ;;
    *) echo "ERROR: unknown arg: $1" >&2; exit 2 ;;
  esac
done

[ -n "$WORKSPACE" ] || { echo "ERROR: --workspace required" >&2; exit 2; }
[ -n "$AGENT" ]    || { echo "ERROR: --agent required" >&2; exit 2; }
case "$AGENT" in
  claude|agy|hermes|grok|opencode|codex) ;;
  *) echo "ERROR: unsupported agent: $AGENT" >&2; exit 2 ;;
esac
[ -n "$SESSION_NAME" ] || { echo "ERROR: --session required" >&2; exit 2; }
export MAM_AUTO_TRUST="$AUTO_TRUST"

# Issue #21 phase 2 (A11): a session resumes only in the directory it ran in
# (its conversation is keyed by that cwd; a class A agent would otherwise start
# a fresh conversation in the wrong tree). Existence first: mam_abs_workspace
# returns a missing path unchanged, which would read as "a different path".
ROW_CWD="$(MAM_STATE_JSON="$(load_state_json)" SESSION_NAME="$SESSION_NAME" python3 -c '
import json, os
d = json.loads(os.environ.get("MAM_STATE_JSON") or "{}")
for s in d.get("herdr_sessions", []):
    if s.get("name") == os.environ["SESSION_NAME"]:
        print((s.get("pane") or {}).get("cwd", "") or ""); break
' 2>/dev/null || true)"
if [ -n "$ROW_CWD" ]; then
  if [ ! -d "$ROW_CWD" ]; then
    echo "ERROR: session '$SESSION_NAME' ran in '$ROW_CWD', which no longer exists (worktree removed?). It cannot be resumed; recreate the worktree at that path, or create a new session." >&2
    exit 2
  fi
  if [ "$(mam_abs_workspace "$ROW_CWD")" != "$(mam_abs_workspace "$WORKSPACE")" ]; then
    echo "ERROR: session '$SESSION_NAME' was created in '$ROW_CWD'; resume it with --workspace '$ROW_CWD' (its conversation is keyed by that directory)." >&2
    exit 2
  fi
fi

# Issue #21 (item 3, D11): the control-plane binding recorded on the row wins
# over the caller's environment (a difference is reported on stderr); a legacy
# row without one uses the caller's binding, which update_yaml_resumed.sh then
# records - on the already-running path too (phase 2, A13). A binding that
# cannot be computed is refused for a worktree and warned about for the
# control root itself (A12), as in create.
ROW_CP="$(MAM_STATE_JSON="$(load_state_json)" SESSION_NAME="$SESSION_NAME" python3 -c "
import json, os
d = json.loads(os.environ.get('MAM_STATE_JSON') or '{}')
for s in d.get('herdr_sessions', []):
    if s.get('name') == os.environ['SESSION_NAME'] and isinstance(s.get('control_plane'), dict):
        print(json.dumps(s['control_plane']))
        break
" 2>/dev/null || true)"
CP_ROOT="$(printf '%s' "$ROW_CP" | python3 -c 'import json,sys
try: print(json.load(sys.stdin).get("workspace_root") or "")
except Exception: print("")' 2>/dev/null || true)"
CP_ROOT="${CP_ROOT:-$WORKSPACE_ROOT}"
cp_rc=0
CP_JSON="$(mam_control_plane_json "$WORKSPACE" "$ROW_CP")" || cp_rc=$?
if [ "$cp_rc" -ne 0 ] || [ -z "$CP_JSON" ]; then
  if [ "$(mam_abs_workspace "$WORKSPACE")" != "$(mam_abs_workspace "$CP_ROOT")" ]; then
    echo "ERROR: cannot compute the control-plane binding (rc=$cp_rc) for --workspace '$WORKSPACE' (control root '$CP_ROOT'); refusing to resume a session that would use the wrong control plane" >&2
    exit 2
  fi
  echo "WARNING: control-plane binding unavailable (rc=$cp_rc); the row is kept without control_plane" >&2
  CP_JSON=""
fi

# 1. Resolve the session id
UUID=$(bash "$(dirname "${BASH_SOURCE[0]}")/resolve_session_id.sh" \
  --workspace "$WORKSPACE" --agent "$AGENT" --session "$SESSION_NAME")

# ISSUE-3: agy/hermes/opencode (Class A) are spawned without a UUID - their
# own conversation id is only assigned by the agent itself on its first turn.
# A session stopped before any message therefore has no UUID to resolve here,
# but IS still cleanly recoverable: relaunching the agent's plain first-run
# spawn command restores the exact state multi-agent-mux-create would have
# produced. claude/grok (Class B) always resolve a UUID via the
# verify_session.py:99-101 assigned-but-unverified escape hatch (see test_t8)
# and never reach this branch - do not extend the fallback to them.
FRESH_SPAWN=0
if [ -z "$UUID" ]; then
  case "$AGENT" in
    agy|hermes|opencode|codex) FRESH_SPAWN=1 ;;
    *)
      echo "ERROR: No saved session for $WORKSPACE ($AGENT). Use multi-agent-mux-create first." >&2
      exit 1
      ;;
  esac
fi

if [ -n "$HERDR_SERVER_OPT" ]; then
  export HERDR_SESSION_NAME="$HERDR_SERVER_OPT"
else
  HERDR_SESSION_NAME="$(resolve_herdr_session "$SESSION_NAME" "$WORKSPACE")"
  export HERDR_SESSION_NAME
fi

if [ -n "$HERDR_WORKSPACE_OPT" ]; then
  export MAM_WS_LABEL="$HERDR_WORKSPACE_OPT"
else
  export MAM_WS_LABEL="$(resolve_herdr_workspace "$SESSION_NAME" "$WORKSPACE")"
fi

# 2. If herdr is alive, print warning or attach.
if herdr has-session -t "$SESSION_NAME" 2>/dev/null; then
  if [ "${DRY_RUN:-0}" = "1" ]; then
    echo "[dry-run] herdr '$SESSION_NAME' already running — nothing to validate"
    exit 0
  fi
  echo "herdr '$SESSION_NAME' already running."
  # Just update YAML to make sure it's set to running
  CONTROL_PLANE_JSON="$CP_JSON" bash "$(dirname "${BASH_SOURCE[0]}")/update_yaml_resumed.sh" \
    --session "$SESSION_NAME" --uuid "$UUID" --agent "$AGENT" --workspace "$WORKSPACE" \
    --herdr-session "$HERDR_SESSION_NAME" \
    ${HERDR_WORKSPACE_OPT:+--herdr-workspace "$HERDR_WORKSPACE_OPT"}
  exit 0
fi

# Resolve absolute path of the agent command to prevent herdr PATH inheritance issues (especially on macOS)
RESOLVED_BIN="$AGENT"
if command -v "$AGENT" >/dev/null 2>&1; then
  RESOLVED_BIN="$(command -v "$AGENT")"
fi

# On macOS, clear quarantine attribute for the agent binary to prevent Gatekeeper hangs
if [ "$(uname)" = "Darwin" ] && [ -f "$RESOLVED_BIN" ]; then
  xattr -d com.apple.quarantine "$RESOLVED_BIN" 2>/dev/null || true
fi

# Determine CMD_FULL via adapter
if [ "$FRESH_SPAWN" = "1" ]; then
  # ISSUE-3: no UUID to resume with - spawn the same plain first-run command
  # multi-agent-mux-create would use (spawn-spec, not resume-spec).
  CMD_FULL="$("$(_delegate_py_bin)" -m lib_py.agents spawn-spec "$AGENT" "$RESOLVED_BIN" "" 0 2>/dev/null || true)"
  if [ -z "$CMD_FULL" ]; then
    case "$AGENT" in
      agy)      CMD_FULL="${RESOLVED_BIN} --dangerously-skip-permissions" ;;
      hermes)   CMD_FULL="${RESOLVED_BIN} --yolo --accept-hooks" ;;
      opencode) CMD_FULL="${RESOLVED_BIN} --auto --agent build" ;;
      codex)    CMD_FULL="${RESOLVED_BIN} --dangerously-bypass-approvals-and-sandbox" ;;
    esac
  fi
else
  CMD_FULL="$("$(_delegate_py_bin)" -m lib_py.agents resume-spec "$AGENT" "$RESOLVED_BIN" "$UUID" "$WORKSPACE" 2>/dev/null || true)"
  if [ -z "$CMD_FULL" ]; then
    case "$AGENT" in
      claude) CMD_FULL="${RESOLVED_BIN} --dangerously-skip-permissions -r $UUID" ;;
      agy)    CMD_FULL="${RESOLVED_BIN} --dangerously-skip-permissions --conversation $UUID" ;;
      hermes) CMD_FULL="${RESOLVED_BIN} --resume $UUID --no-restore-cwd --yolo --accept-hooks" ;;
      grok)   CMD_FULL="${RESOLVED_BIN} --resume $UUID --permission-mode bypassPermissions" ;;
      opencode) CMD_FULL="${RESOLVED_BIN} --session $UUID --auto --agent build" ;;
      codex)  CMD_FULL="${RESOLVED_BIN} resume --dangerously-bypass-approvals-and-sandbox $UUID" ;;
      *)      echo "ERROR: unsupported agent: $AGENT" >&2; exit 2 ;;
    esac
  fi
fi

# Validate binary exists and is executable
if [ -f "$RESOLVED_BIN" ] || [[ "$RESOLVED_BIN" == /* ]] || [[ "$RESOLVED_BIN" == ~/* ]]; then
  if [ ! -x "$RESOLVED_BIN" ]; then
    echo "ERROR: Agent binary is not executable: $RESOLVED_BIN" >&2
    exit 1
  fi
else
  if ! command -v "$RESOLVED_BIN" >/dev/null 2>&1; then
    echo "ERROR: Agent binary not found in PATH: $RESOLVED_BIN" >&2
    exit 1
  fi
fi

# The binding (computed above) is forwarded to the pane only when it differs
# from --workspace's own; a forward with whitespace is refused (spawn path only).
CP_PREFIX=""
if [ -n "$CP_JSON" ]; then
  cp_rc=0
  CP_PREFIX="$(mam_control_plane_prefix "$CP_JSON")" || cp_rc=$?
  if [ "$cp_rc" -eq 3 ]; then
    echo "ERROR: control-plane path contains whitespace; cannot forward to the pane" >&2
    exit 2
  fi
fi

if [ "${DRY_RUN:-0}" = "1" ]; then
  echo "[dry-run] would spawn: $CMD_FULL"
  exit 0
fi

if [ "$AGENT" = "opencode" ]; then
  if [ -z "${OPENCODE_PERMISSION:-}" ]; then
    export OPENCODE_PERMISSION='{"*":"allow"}'
  fi
fi

# 4. Spawn new agent session (delegates to herdr translation shim)
_herdr new-session -d -s "$SESSION_NAME" -c "$WORKSPACE" "$CP_PREFIX$CMD_FULL"
# Issue #24: every agent, the same call create makes. The signatures and accept
# keys come from the agent adapter; this used to run only for claude, so a
# resumed agy/grok/codex sat on its trust prompt.
handle_startup_dialogs "$SESSION_NAME" 20 "$AGENT"

# Wait for TUI readiness or let it settle
sleep 2

# 5. Update agent-sessions.yaml: status running, last_visible_status
CONTROL_PLANE_JSON="$CP_JSON" bash "$(dirname "${BASH_SOURCE[0]}")/update_yaml_resumed.sh" \
  --session "$SESSION_NAME" --uuid "$UUID" --agent "$AGENT" --workspace "$WORKSPACE" \
  --herdr-session "$HERDR_SESSION_NAME" --cmd-full "$CMD_FULL" \
  ${HERDR_WORKSPACE_OPT:+--herdr-workspace "$HERDR_WORKSPACE_OPT"}

echo "Successfully resumed $SESSION_NAME ($AGENT)"