#!/usr/bin/env bash
# Copyright 2026 Hee-Suk Kim <hskim@dilluti0n.com>
# SPDX-License-Identifier: GPL-3.0-only

set -euo pipefail

. lib.bash

usage() {
    cat <<EOF
usage: ${NAME} [-nrch] [-p <chain-ish>] [-t <name>] [-e <endpoint>] [-m <model>]
  -e     API <endpoint> (PLM_ENDPOINT)
  -m     Model name (PLM_MODEL)
  -p     Parent <chain-ish> to chain on (default HEAD)
  -t     Save the current HEAD as <name> before asking
  -n     Start new conversation
  -r     Do not accept or chain input (use with -p)
  -c     Chain user turn only, no API call done
  -h     Show this help
EOF
}

parent=HEAD parent_arg= resend= ref= only_chain= noderef=
while getopts he:m:p:t:nrc o; do
    case $o in
        h) usage; exit 0 ;;
        e) export PLM_ENDPOINT="$OPTARG" ;;
        m) export PLM_MODEL="$OPTARG" ;;
        p) parent="$OPTARG" ;;
        t) ref="$OPTARG" ;;
        n) parent= ;;
        r) resend=1 ;;
        c) only_chain=1 ;;
        *) usage; exit 1 ;;
    esac
done
shift $((OPTIND - 1))

[[ -n $ref ]] && sib save -- "$ref"

# An unborn HEAD has no parent. The first update should detach HEAD
sib rev-parse HEAD &>/dev/null || {
    noderef=--no-deref
    [[ $parent == HEAD ]] && parent=
}

if [[ -z $parent ]]; then
    # -n is set, should detach HEAD to not taint existing ref
    noderef=--no-deref
else
    tmp=$(sib rev-parse "$parent") || die bad parent: $parent
    parent=$tmp
fi

if [[ -z $resend ]]; then
    [[ -t 0 ]] && echo '(stdin, Ctrl+D to send)' >&2

    # rev-parse prints empty means there is no ref pointed to by
    # $parent. In this case, start a new chain and update HEAD.
    parent_arg="${parent:+-p $parent}"
    parent=$(plm-wrap -f text -t plm | sib chain-trace-json $parent_arg)
fi

[[ -n $parent ]] || die 'refuse to do worthless job with -nr'

reflog=$(sib show -c $parent | tr -s '[:space:]' ' ' | cut -c1-72)

[[ -n $only_chain ]] && {
    sib update-ref -m "ask (user): ${reflog:-$parent}" $noderef HEAD $parent
    exit
}

{
    res=$(sib rev-jsonl $parent \
              | plm-wrap -f plm -t request \
              | plm-send) || die 'fail to recieve API call'

    [[ -n $res ]] || die 'fail to recieve API call'

    [[ -z "${SIB_DEBUG:-}" ]] || echo "sib-ask: res: $res" >&2
} 3>&1

new=$(plm-wrap -f response -t plm -r assistant <<<"$res" | sib chain-trace-json -p $parent) ||
    die something wrong
[[ -n $new ]] || die "sib chain-trace-json -p $parent gives empty output"

sib update-ref -m "ask: ${reflog:-$new}" $noderef HEAD $new