#!/bin/sh
# rclaude — durable Claude Code sessions, local or remote.
#
# Two layers of resilience:
#   1. tmux on <host> survives terminal/transport drops.
#   2. `claude --continue` resumes the per-directory session from disk after
#      the host itself dies (reboot, crash, OOM).
#
# Each invocation starts a fresh Claude session in a new named tmux window.
# To reattach an existing session: `rclaude resume [pattern]`
# To resume a Claude conversation from disk after host loss: `rclaude resume` picks
# up the on-disk session via `claude --continue`.
#
# Permission mode: --dangerously-skip-permissions is on by default. Override
# with RCLAUDE_PERMS=default (or any --permission-mode value).
#
# Tmux config sync: the repo's canonical tmux.conf is pushed to the target
# host's ~/.tmux.d/session-tools.conf on every launch and source-lined from
# ~/.tmux.conf. Disable with RCLAUDE_SYNC_TMUX=0, or set =once to only write
# if the source-line isn't already present.
#
# Hosts scanned by `list`/`resume` default to: local + apricot + plum (the
# non-local one is dialed; the local one is rendered as "local"). Override
# with RCLAUDE_HOSTS="apricot black quinn-vps".
#
# Usage:
#   rclaude                                  # local, $PWD
#   rclaude .                                # local, $PWD
#   rclaude <host>                           # remote: $PWD mirrored under remote $HOME
#   rclaude <host> .                         # same as above (explicit form)
#   rclaude <host> <dir>                     # remote (or local) at <dir>
#   rclaude list                             # tmux + per-project disk view
#   rclaude list sessions                    # tmux + per-session disk view (uuid + snippet)
#   rclaude resume [pattern]                 # reattach / resume by uuid prefix, snippet,
#                                            # tmux name, or cwd substring (interactive
#                                            # picker on >1 match)
#
# Mirror semantics: if local $PWD is $HOME/X/Y, the remote dir defaults to
# ~/X/Y on the remote (the remote's $HOME, not $HOME from this machine).
# If $PWD is outside $HOME, falls back to the remote's $HOME.

set -eu

# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

# Resolve $0 to its real path, correctly handling relative symlinks at each hop.
resolve_self() {
    _rs=$0
    while [ -L "$_rs" ]; do
        _link=$(readlink "$_rs")
        case "$_link" in
            /*) _rs="$_link" ;;
            *)  _rs="$(dirname "$_rs")/$_link" ;;
        esac
    done
    printf '%s' "$_rs"
}

is_local() {
    case $1 in
        local|localhost|127.0.0.1|::1) return 0 ;;
    esac
    [ "$1" = "$(hostname)" ] && return 0
    [ "$1" = "$(hostname -s 2>/dev/null)" ] && return 0
    return 1
}

# List claude-* tmux sessions on a host. Output one row per session:
#   <host>\ttmux\t<session_name>\t<detail_from_tmux_ls>
list_tmux_on() {
    _host=$1
    if is_local "$_host"; then
        command -v tmux >/dev/null 2>&1 || return 0
        _raw=$(tmux ls 2>/dev/null || true)
    else
        _raw=$(ssh -o BatchMode=yes -o ConnectTimeout=3 "$_host" 'tmux ls 2>/dev/null' || true)
    fi
    # tmux ls lines look like:  claude-foo: 1 windows (created ...) [80x24]
    printf %s "$_raw" | awk -v host="$_host" '
        /^claude-/ {
            name=$1; sub(/:$/, "", name);
            $1="";
            sub(/^[[:space:]]+/, "");
            printf "%s\ttmux\t%s\t%s\n", host, name, $0
        }
    '
}

# List on-disk Claude project sessions on a host (via _claude-projects helper).
# Output one row per project:
#   <host>\tdisk\t<cwd>\t<sessions=N, last used <relative-time>>
list_disk_on() {
    _host=$1
    _helper_dir=$(dirname "$(resolve_self)")
    if is_local "$_host"; then
        _raw=$("$_helper_dir/_claude-projects" 2>/dev/null || true)
    else
        # Send the helper over stdin so we don't depend on a pre-installed copy
        # on the remote (and to dodge quoting issues).
        _raw=$(ssh -o BatchMode=yes -o ConnectTimeout=3 "$_host" 'python3 -' < "$_helper_dir/_claude-projects" 2>/dev/null || true)
    fi
    _now=$(date +%s)
    printf %s "$_raw" | awk -F'\t' -v host="$_host" -v now="$_now" '
        function rel(secs,   abs, s) {
            abs = (secs < 0) ? -secs : secs
            if (abs < 60)         s = abs " seconds"
            else if (abs < 3600)  s = int(abs/60) " min"
            else if (abs < 86400) s = int(abs/3600) " hours"
            else                  s = int(abs/86400) " days"
            return s " ago"
        }
        NF >= 3 {
            printf "%s\tdisk\t%s\tsessions=%s, last used %s\n", host, $2, $3, rel(now - $1)
        }
    '
}

# List on-disk Claude sessions per UUID on a host (via _claude-projects --sessions).
# Output one row per session jsonl:
#   <host>\tsession\t<uuid>\t<snippet>\t<cwd> · <relative-time>
list_sessions_on() {
    _host=$1
    _helper_dir=$(dirname "$(resolve_self)")
    if is_local "$_host"; then
        _raw=$("$_helper_dir/_claude-projects" --sessions 2>/dev/null || true)
    else
        _raw=$(ssh -o BatchMode=yes -o ConnectTimeout=3 "$_host" 'python3 - --sessions' < "$_helper_dir/_claude-projects" 2>/dev/null || true)
    fi
    _now=$(date +%s)
    printf %s "$_raw" | awk -F'\t' -v host="$_host" -v now="$_now" '
        function rel(secs,   abs, s) {
            abs = (secs < 0) ? -secs : secs
            if (abs < 60)         s = abs " seconds"
            else if (abs < 3600)  s = int(abs/60) " min"
            else if (abs < 86400) s = int(abs/3600) " hours"
            else                  s = int(abs/86400) " days"
            return s " ago"
        }
        NF >= 3 {
            snippet = ($4 == "" ? "(no user text)" : $4)
            printf "%s\tsession\t%s\t%s\t%s · %s\n", host, $2, snippet, $3, rel(now - $1)
        }
    '
}

# Combined enumeration: tmux first (live), then on-disk per-project.
list_all_on() {
    list_tmux_on "$1"
    list_disk_on "$1"
}

# Resume-search enumeration: tmux + per-session UUIDs/snippets.
list_search_on() {
    list_tmux_on "$1"
    list_sessions_on "$1"
}

# Push the canonical session-tools tmux fragment to <host> and ensure
# ~/.tmux.conf sources it. Idempotent; runs on every launch so config changes
# in the repo propagate without re-running install.sh on each host.
#
# Controlled by RCLAUDE_SYNC_TMUX:
#   1 (default)  auto-sync on every launch
#   0            never sync (e.g. host has a hand-tuned tmux config you don't
#                want clobbered by a stray source-file line)
#   once         sync only if the source-file line isn't already present;
#                useful on hosts where you've audited the fragment once and
#                don't want repeated writes
#
# Silent no-op if the repo fragment can't be located.
sync_tmux_conf() {
    _host=$1
    _mode=${RCLAUDE_SYNC_TMUX:-1}
    case $_mode in
        0|off|no|false) return 0 ;;
    esac
    _self=$(resolve_self)
    _repo=$(cd "$(dirname "$_self")/.." 2>/dev/null && pwd)
    _frag="$_repo/tmux.conf"
    [ -f "$_frag" ] || return 0
    _guard=""
    case $_mode in
        once) _guard='grep -q "session-tools.conf" ~/.tmux.conf 2>/dev/null && exit 0;' ;;
    esac
    _remote_cmd="${_guard} "'mkdir -p ~/.tmux.d && cat > ~/.tmux.d/session-tools.conf && { grep -q "session-tools.conf" ~/.tmux.conf 2>/dev/null || printf "source-file ~/.tmux.d/session-tools.conf\n" >> ~/.tmux.conf; } && tmux source-file ~/.tmux.conf 2>/dev/null || true'
    if is_local "$_host"; then
        sh -c "$_remote_cmd" < "$_frag" 2>/dev/null || true
    else
        ssh -o BatchMode=yes -o ConnectTimeout=5 "$_host" "$_remote_cmd" < "$_frag" 2>/dev/null || true
    fi
}

# All hosts to scan for list/resume. Defaults to "apricot plum" so resume
# discovery works symmetrically from either host (the local one is rendered
# as "local" and remote ones are filtered to drop any host that matches the
# current machine).
scan_hosts() {
    printf "local\n"
    for h in ${RCLAUDE_HOSTS:-apricot plum}; do
        is_local "$h" && continue
        printf "%s\n" "$h"
    done
}

# ---------------------------------------------------------------------------
# Subcommands
# ---------------------------------------------------------------------------

cmd_list() {
    _mode=${1:-all}   # all | tmux | disk | sessions
    printf "%-10s  %-7s  %-60s  %s\n" "HOST" "KIND" "SESSION/CWD/UUID" "DETAIL"
    scan_hosts | while IFS= read -r h; do
        case $_mode in
            tmux)             list_tmux_on     "$h" ;;
            disk)             list_disk_on     "$h" ;;
            sessions|--sessions)
                              list_tmux_on     "$h"
                              list_sessions_on "$h" ;;
            *)                list_all_on      "$h" ;;
        esac | awk -F'\t' '{
            # Tmux/disk rows: $3 is the display target. Session rows: $3=uuid,
            # $4=snippet (show snippet, abbreviate uuid into DETAIL via $5).
            if ($2 == "session") {
                uuid_short = substr($3, 1, 8)
                detail = (NF >= 5 ? $5 : "") "  [" uuid_short "]"
                printf "%-10s  %-7s  %-60.60s  %s\n", $1, $2, $4, detail
            } else {
                printf "%-10s  %-7s  %-60.60s  %s\n", $1, $2, $3, $4
            }
        }'
    done
}

# Resume strategy:
#   - 1 match                  → attach directly
#   - 2+ matches                → single-key picker (1-9 then a-z, max 35)
#   - matches a tmux row       → ssh+tmux attach (preserves the live conversation)
#   - matches a session UUID   → ssh+tmux+claude --resume <uuid> at recorded cwd
#   - matches a snippet/cwd    → same as session (the row identifies a UUID)
#
# Pattern matching is case-insensitive substring across host/kind/uuid/snippet/cwd.
# An empty pattern lists everything (interactive picker).
cmd_resume() {
    _pattern=${1:-}
    _matches=$(scan_hosts | while IFS= read -r h; do list_search_on "$h"; done)
    if [ -n "$_pattern" ]; then
        _matches=$(printf '%s\n' "$_matches" | grep -F -i -- "$_pattern" || true)
    fi
    _count=0
    [ -n "$_matches" ] && _count=$(printf '%s\n' "$_matches" | wc -l | tr -d ' ')
    if [ "$_count" -eq 0 ]; then
        echo "no matching sessions${_pattern:+ for pattern '$_pattern'}" >&2
        exit 1
    fi
    if [ "$_count" -gt 1 ]; then
        _keys="123456789abcdefghijklmnopqrstuvwxyz"
        if [ "$_count" -gt 35 ]; then
            echo "too many matches ($_count); refine pattern" >&2
            exit 1
        fi
        # For sessions, display the human-readable snippet (col 4) rather
        # than the bare UUID (col 3); for tmux/disk the existing col 3 is
        # already the right thing to show.
        _fmt_row='function display(){ if ($2 == "session") return $4 "  [" substr($3,1,8) "]"; return $3 } { printf "%-10s  %-7s  %s", $1, $2, display() }'
        if [ ! -t 0 ] || [ ! -t 2 ]; then
            echo "multiple matches and no tty for picker; refine pattern:" >&2
            printf '%s\n' "$_matches" | awk -F'\t' "$_fmt_row"'{printf "\n"}' >&2
            exit 1
        fi
        _i=0
        printf '%s\n' "$_matches" | while IFS= read -r _line; do
            _i=$((_i + 1))
            _k=$(printf %s "$_keys" | cut -c"$_i")
            printf '  [%s]  %s\n' "$_k" \
                "$(printf %s "$_line" | awk -F'\t' "$_fmt_row")" >&2
        done
        _last_key=$(printf %s "$_keys" | cut -c"$_count")
        printf 'select [1-%s]: ' "$_last_key" >&2
        _old=$(stty -g 2>/dev/null || true)
        stty -icanon -echo min 1 time 0 2>/dev/null || true
        _key=$(dd bs=1 count=1 2>/dev/null </dev/tty || true)
        [ -n "$_old" ] && stty "$_old" 2>/dev/null || true
        printf '%s\n' "$_key" >&2
        _idx=0
        _c=1
        while [ "$_c" -le "$_count" ]; do
            if [ "$(printf %s "$_keys" | cut -c"$_c")" = "$_key" ]; then
                _idx=$_c; break
            fi
            _c=$((_c + 1))
        done
        if [ "$_idx" -eq 0 ]; then
            echo "rclaude: invalid selection: '$_key'" >&2
            exit 1
        fi
        _matches=$(printf '%s\n' "$_matches" | sed -n "${_idx}p")
    fi
    _host=$(printf '%s\n' "$_matches" | awk -F'\t' 'NR==1{print $1}')
    _kind=$(printf '%s\n' "$_matches" | awk -F'\t' 'NR==1{print $2}')
    _target=$(printf '%s\n' "$_matches" | awk -F'\t' 'NR==1{print $3}')
    # Sessions carry their cwd in column 5 (formatted "<cwd> · <rel-time>");
    # extract the cwd half for the launch dir.
    _session_cwd=$(printf '%s\n' "$_matches" | awk -F'\t' 'NR==1{print $5}' | awk -F' · ' '{print $1}')
    case $_kind in
        tmux)
            if is_local "$_host"; then
                exec tmux attach -t "$_target"
            else
                exec ssh -t "$_host" tmux attach -t "$_target"
            fi
            ;;
        disk)
            # Spawn tmux + claude --continue at the recorded cwd.
            RCLAUDE_RESUME=1 exec "$0" "$_host" "$_target"
            ;;
        session)
            # Spawn tmux + claude --resume <uuid> at the session's recorded cwd.
            if [ -z "$_session_cwd" ]; then
                echo "rclaude: session $_target has no recorded cwd" >&2
                exit 1
            fi
            RCLAUDE_RESUME_ID=$_target exec "$0" "$_host" "$_session_cwd"
            ;;
    esac
}

# ---------------------------------------------------------------------------
# Dispatch
# ---------------------------------------------------------------------------

cmd_version() {
    _self=$(resolve_self)
    _repo=$(cd "$(dirname "$_self")/.." 2>/dev/null && pwd)
    if [ -d "$_repo/.git" ] && command -v git >/dev/null 2>&1; then
        _sha=$(git -C "$_repo" rev-parse --short HEAD 2>/dev/null)
        _dirty=""
        [ -n "$(git -C "$_repo" status --porcelain 2>/dev/null)" ] && _dirty="-dirty"
        _date=$(git -C "$_repo" log -1 --format=%cd --date=short HEAD 2>/dev/null)
        printf 'rclaude (session-tools) %s%s  %s  %s\n' "$_sha" "$_dirty" "$_date" "$_repo"
    else
        printf 'rclaude (session-tools)  %s\n' "$_repo"
    fi
}

case ${1:-} in
    list)            shift; cmd_list    "$@"; exit ;;
    resume)          shift; cmd_resume  "$@"; exit ;;
    -v|--version)    cmd_version; exit ;;
esac

# ---------------------------------------------------------------------------
# Default behavior: launch (or reattach to) a session.
# ---------------------------------------------------------------------------

# Argument resolution:
#   `rclaude`        → local, $PWD
#   `rclaude .`      → local, $PWD
#   `rclaude <host>` → host, default dir (~ remote, $PWD local)
#   `rclaude <host> <dir>` → host, dir (with `.` resolving to $PWD)
if [ $# -eq 0 ] || [ "${1:-}" = "." ]; then
    host=local
    dir=$PWD
else
    host=$1
    dir=${2:-}
fi

# Defaults + `.` expansion now that we know whether we're local or remote.
if is_local "$host"; then
    case ${dir:-.} in
        .|"") dir=$PWD ;;
    esac
else
    # Remote default: mirror local $PWD relative to $HOME onto the remote's
    # $HOME. Same behavior for omitted dir or explicit `.`. Falls back to
    # remote $HOME if local $PWD isn't under $HOME.
    if [ "$dir" = "." ] || [ -z "$dir" ]; then
        case $PWD in
            "$HOME")     dir=\~ ;;
            "$HOME"/*)   _rel=${PWD#"$HOME"/}; dir="~/$_rel" ;;
            *)           dir=\~ ;;
        esac
    fi
fi

slug=$(printf %s "$dir" | sed -e 's|^[~/]*||' -e 's|[^A-Za-z0-9]|-|g')
[ -z "$slug" ] && slug=home
session="claude-$(whoami)-${slug}-$(date +%s)"

perms=${RCLAUDE_PERMS:-bypass}
case $perms in
    bypass) flag="--dangerously-skip-permissions" ;;
    *)      flag="--permission-mode $perms" ;;
esac

# Inner command for the tmux pane. If claude exits nonzero OR ends in under
# 2 seconds (usually a misconfig: missing dir, locked session, crashed
# claude), the pane stays open with the exit code visible instead of
# silently dying and dragging the whole tmux session + ssh transport down
# with it. A real interactive session lasts much longer than 2s, so a clean
# /exit closes the pane normally.
build_inner() {
    # Single-line, single-quote-safe. Variables prefixed with rc_ to avoid
    # collision with anything in the user's shell.
    #
    # Note: launch path uses plain `claude` (fresh session). Each invocation
    # creates a new uniquely-named tmux session. Reattach to a live session
    # via `rclaude resume <pattern>`; disk-resume after host death likewise.
    _resume_flag=""
    if [ -n "${RCLAUDE_RESUME_ID:-}" ]; then
        _resume_flag="--resume ${RCLAUDE_RESUME_ID}"
    elif [ "${RCLAUDE_RESUME:-0}" = "1" ]; then
        _resume_flag="--continue"
    fi
    printf '%s' \
        "cd ${1} && rc_t=\$(date +%s); claude ${_resume_flag} ${flag}; rc_ec=\$?; " \
        "rc_e=\$(date +%s); rc_d=\$((rc_e - rc_t)); " \
        "if [ \$rc_ec -ne 0 ] || [ \$rc_d -lt 2 ]; then " \
        "printf '\\n[rclaude] claude exited in %ds with code %d\\n' \$rc_d \$rc_ec; " \
        "printf '[rclaude] press enter to close pane (or Ctrl-b d to detach)... '; " \
        "read rc_; fi"
}

if is_local "$host"; then
    if ! command -v tmux >/dev/null 2>&1; then
        echo "rclaude: tmux not installed locally — install via 'brew install tmux' (macOS) or your package manager" >&2
        exit 1
    fi
    if ! cd "$dir" 2>/dev/null; then
        echo "rclaude: local directory not found: $dir" >&2
        exit 1
    fi
    sync_tmux_conf local
    exec tmux new-session -s "$session" "$(build_inner "$dir")"
fi

# Remote: pre-flight the directory so a typo or missing path fails loudly
# here instead of silently killing the tmux pane and closing the ssh
# transport (which looks like a generic 'Connection closed' to the user).
if ! ssh -o BatchMode=yes -o ConnectTimeout=5 "$host" "test -d ${dir}" 2>/dev/null; then
    echo "rclaude: directory not found on $host: $dir" >&2
    case $dir in
        *@proj/*|*@apps/*|*@pkg/*)
            echo "  hint: '@proj/@apps/@pkg' are Claude-instruction aliases, not real shell paths." >&2
            echo "  See ~/.claude/instructions/project-paths.md for the real ~/Code/<bucket>/<project> mapping." >&2
            ;;
    esac
    exit 1
fi

sync_tmux_conf "$host"
inner=$(build_inner "$dir")
exec ssh -t "$host" "tmux new-session -s '${session}' \"${inner}\""