#!/usr/bin/env bash
# nc-insert-protocol.sh — write side of Example 1 (and general NetConfig writes).
#
# Two operations:
#
#   1. insert      — append a NEW protocol block to a NetConfig file.
#                    Modes: end (default) | after-protocol NAME | before-protocol NAME
#
#   2. add-route   — splice a NEW route entry into an existing protocol's
#                    DATAXLATE block. The route entry is the inner `{ … }`
#                    object (with CACHEMSG, ROUTE_DETAILS, TRXID, etc.) that
#                    nc-make-jump.sh emits as the route_add snippet.
#
# Both operations go through journal.sh: snapshot the original, write a diff
# entry, then atomically replace the target. Roll back later via:
#   larry-rollback.sh --target <netconfig>      # newest-first
#   larry-rollback.sh --session <session-id>    # whole session
#   larry-rollback.sh --entry <entry-id>        # one specific write
#
# Usage:
#   nc-insert-protocol.sh insert <netconfig> <block_file> [--mode end|after|before --anchor NAME]
#   nc-insert-protocol.sh add-route <netconfig> <protocol_name> <route_file>
#
#   <block_file>   path to a file containing the TCL `protocol NAME { … }` block to insert
#   <route_file>   path to a file containing the route entry (just the inner `{ … }`)
#
# Exit codes: 0 OK, 2 usage, 3 target not found, 4 already exists / wouldn't change
set -o pipefail

NC_SELF="$0"
LIB_DIR="$(cd "$(dirname "$NC_SELF")" && pwd)"
NCP="$LIB_DIR/nc-parse.sh"
JOURNAL="$LIB_DIR/journal.sh"

die() { printf 'nc-insert-protocol: %s\n' "$*" >&2; exit 1; }

# v0.7.5: shared CR-safety primitives.  awk-emitted line numbers feed
# `$((end_line - 1))` / `head -n $((start_line - 1))` / `tail -n +$((... + 1))`
# arithmetic and shell positionals; a CR-tainted awk would crash all three.
if [ -r "$LIB_DIR/cygwin-safe.sh" ]; then
  # shellcheck disable=SC1090,SC1091
  . "$LIB_DIR/cygwin-safe.sh"
else
  coerce_int() { local r="${1:-}" d="${2:-0}" c; c=$(printf '%s' "$r" | tr -cd '0-9'); printf '%s' "${c:-$d}"; }
fi

# Source journal so we can call journal_write directly
# shellcheck disable=SC1090
. "$JOURNAL"

cmd_insert() {
  local nc="$1" block_file="$2"
  shift 2
  local mode="end" anchor=""
  while [ $# -gt 0 ]; do
    case "$1" in
      --mode)    shift; mode="$1" ;;
      --anchor)  shift; anchor="$1" ;;
      *)         die "unknown flag for insert: $1" ;;
    esac
    shift
  done

  [ -f "$nc" ]         || { die "no such NetConfig: $nc"; }
  [ -f "$block_file" ] || { die "no such block file: $block_file"; }

  # Extract block name to detect collisions
  local block_name
  block_name=$(awk '/^protocol [A-Za-z0-9_]+/ {print $2; exit}' "$block_file")
  [ -n "$block_name" ] || die "block file does not start with 'protocol NAME {' — bad input"

  if "$NCP" list-protocols "$nc" 2>/dev/null | grep -qx "$block_name"; then
    die "protocol '$block_name' already exists in $nc — refusing to insert. Use a different name or update the existing block via a different tool."
  fi

  local tmp; tmp=$(mktemp)

  case "$mode" in
    end)
      cat "$nc" > "$tmp"
      # Ensure trailing newline before appending
      [ -n "$(tail -c1 "$tmp")" ] && printf '\n' >> "$tmp"
      printf '\n' >> "$tmp"
      cat "$block_file" >> "$tmp"
      printf '\n' >> "$tmp"
      ;;
    after)
      [ -n "$anchor" ] || die "--mode after needs --anchor NAME"
      local end_line
      end_line=$("$NCP" list-protocols "$nc" >/dev/null 2>&1
                 # Compute end line via the same logic as protocol-block
                 awk -v target="$anchor" '
                   BEGIN { depth=0; in_block=0; name="" }
                   /^protocol [A-Za-z0-9_]+ \{$/ && !in_block {
                     name=$2; depth=1; in_block=1
                     if (name==target) start=NR
                     next
                   }
                   in_block {
                     n_open=gsub(/\{/,"{",$0); n_close=gsub(/\}/,"}",$0)
                     depth += n_open - n_close
                     if (depth==0) {
                       if (name==target) { print NR; exit }
                       in_block=0; name=""
                     }
                   }' "$nc")
      [ -n "$end_line" ] || die "anchor protocol not found: $anchor"
      # v0.7.5: coerce_int — awk-emitted NR can have a trailing CR on
      # Cygwin-awk; would crash $((end_line + 1)) arithmetic.
      end_line=$(coerce_int "$end_line" 0)
      head -n "$end_line" "$nc"  > "$tmp"
      printf '\n' >> "$tmp"
      cat "$block_file" >> "$tmp"
      printf '\n' >> "$tmp"
      tail -n +$((end_line + 1)) "$nc" >> "$tmp"
      ;;
    before)
      [ -n "$anchor" ] || die "--mode before needs --anchor NAME"
      local start_line
      start_line=$("$NCP" protocol-line "$nc" "$anchor" 2>/dev/null)
      [ -n "$start_line" ] || die "anchor protocol not found: $anchor"
      # v0.7.5: coerce_int — protocol-line is awk-based; CR-taint defense.
      start_line=$(coerce_int "$start_line" 0)
      head -n $((start_line - 1)) "$nc" > "$tmp"
      cat "$block_file" >> "$tmp"
      printf '\n' >> "$tmp"
      tail -n +"$start_line" "$nc" >> "$tmp"
      ;;
    *) die "bad --mode: $mode (use end|after|before)" ;;
  esac

  # Hand off to journal for atomic backup+write
  local entry_id
  entry_id=$(journal_write "$nc" "$tmp")
  rm -f "$tmp"
  printf 'inserted protocol %s into %s (mode=%s)\n' "$block_name" "$nc" "$mode"
  printf 'journal entry: %s\n' "$entry_id"
  printf 'rollback: larry-rollback.sh --entry %s   OR   larry-rollback.sh --target %s\n' "$entry_id" "$nc"
}

cmd_add_route() {
  local nc="$1" prot="$2" route_file="$3"
  [ -f "$nc" ]         || die "no such NetConfig: $nc"
  [ -f "$route_file" ] || die "no such route file: $route_file"

  # Find the protocol's line range
  local start end
  start=$("$NCP" protocol-line "$nc" "$prot" 2>/dev/null)
  [ -n "$start" ] || die "no such protocol: $prot"

  # Compute end-line of the protocol block
  end=$(awk -v s="$start" '
    NR == s { depth = 1; in_block = 1; next }
    in_block {
      n_open  = gsub(/\{/, "{", $0)
      n_close = gsub(/\}/, "}", $0)
      depth += n_open - n_close
      if (depth == 0) { print NR; exit }
    }
  ' "$nc")
  [ -n "$end" ] || die "could not determine end of protocol block: $prot"

  # Find the DATAXLATE inner block boundaries (just inside the protocol).
  # Lines look like:
  #     { DATAXLATE {
  #         {existing route 1}
  #         {existing route 2}
  #     } }
  local dx_start dx_end
  dx_start=$(awk -v s="$start" -v e="$end" '
    NR>s && NR<e && /^[[:space:]]+\{ DATAXLATE \{$/ { print NR; exit }
  ' "$nc")

  if [ -z "$dx_start" ]; then
    # Handle the empty case:  { DATAXLATE { } }   or   { DATAXLATE {<blank> } }
    # If empty, replace with a populated block on a single line plus the new route.
    local dx_empty_line
    dx_empty_line=$(awk -v s="$start" -v e="$end" '
      NR>s && NR<e && /^[[:space:]]+\{ DATAXLATE \{[[:space:]]*$/ { print NR; exit }
      NR>s && NR<e && /^[[:space:]]+\{ DATAXLATE \{[[:space:]]*\}[[:space:]]*\}/ { print NR; exit }
    ' "$nc")
    [ -n "$dx_empty_line" ] || die "could not locate DATAXLATE block in protocol $prot"
    dx_start="$dx_empty_line"
  fi

  # Find the matching close of the DATAXLATE block:
  # search forward from dx_start, counting braces to find the line where
  # depth-since-dx_start returns to 0.
  dx_end=$(awk -v s="$dx_start" -v e="$end" '
    NR>=s && NR<=e {
      n_open = gsub(/\{/, "{", $0)
      n_close = gsub(/\}/, "}", $0)
      if (NR == s) {
        # The DATAXLATE-open line; the outer "{ DATAXLATE {" has 2 opens
        depth = 0
      }
      depth += n_open - n_close
      if (NR > s && depth <= -2) {  # closing "} }" brings us down 2 levels
        print NR; exit
      }
    }
  ' "$nc")
  # If our naive count failed, try a simpler approach: find next line that is
  # exactly the closing pattern of DATAXLATE  (    } } at the appropriate indent).
  if [ -z "$dx_end" ]; then
    dx_end=$(awk -v s="$dx_start" -v e="$end" '
      NR>s && NR<=e && /^[[:space:]]+\}[[:space:]]\}[[:space:]]*$/ { print NR; exit }
    ' "$nc")
  fi
  [ -n "$dx_end" ] || die "could not locate end of DATAXLATE block in protocol $prot"

  # v0.7.5: coerce_int on every awk-emitted line number before it lands in
  # arithmetic (head -n / tail -n +N) — Cygwin awk.exe CR-taint defense.
  start=$(coerce_int "$start" 0)
  end=$(coerce_int "$end" 0)
  dx_start=$(coerce_int "$dx_start" 0)
  dx_end=$(coerce_int "$dx_end" 0)

  # Indent the route content to match the DATAXLATE inner indentation (8 spaces typical).
  local indent="        "
  local indented_route; indented_route=$(awk -v IND="$indent" '{print IND $0}' "$route_file")

  # Build the new file:
  #   lines 1..dx_start
  #   route content (indented)
  #   lines dx_start+1..end of file
  # Skip the simple "empty" case: if dx_start was a "{ DATAXLATE {} }" single line,
  # we need to split it. Detect by reading that line.
  local dx_start_line; dx_start_line=$(sed -n "${dx_start}p" "$nc")
  local tmp; tmp=$(mktemp)

  if [[ "$dx_start_line" =~ \{[[:space:]]DATAXLATE[[:space:]]\{[[:space:]]*\}[[:space:]]*\}[[:space:]]*$ ]]; then
    # Single-line "{ DATAXLATE { } }" — replace with multi-line form
    head -n $((dx_start - 1)) "$nc" > "$tmp"
    printf '    { DATAXLATE {\n' >> "$tmp"
    printf '%s\n' "$indented_route" >> "$tmp"
    printf '    } }\n' >> "$tmp"
    tail -n +$((dx_start + 1)) "$nc" >> "$tmp"
  else
    head -n "$dx_start" "$nc" > "$tmp"
    printf '%s\n' "$indented_route" >> "$tmp"
    tail -n +$((dx_start + 1)) "$nc" >> "$tmp"
  fi

  local entry_id
  entry_id=$(journal_write "$nc" "$tmp")
  rm -f "$tmp"
  printf 'added route to protocol %s in %s (DATAXLATE block at line %s)\n' "$prot" "$nc" "$dx_start"
  printf 'journal entry: %s\n' "$entry_id"
  printf 'rollback: larry-rollback.sh --entry %s   OR   larry-rollback.sh --target %s\n' "$entry_id" "$nc"
}

# ─────────────────────────────────────────────────────────────────────────────
SUB="${1:-help}"
case "$SUB" in
  insert)
    [ $# -ge 3 ] || { echo "usage: $0 insert <netconfig> <block_file> [--mode end|after|before --anchor NAME]" >&2; exit 2; }
    cmd_insert "$2" "$3" "${@:4}" ;;
  add-route)
    [ $# -ge 4 ] || { echo "usage: $0 add-route <netconfig> <protocol_name> <route_file>" >&2; exit 2; }
    cmd_add_route "$2" "$3" "$4" ;;
  help|-h|--help) sed -n '2,30p' "$NC_SELF" ;;
  *) echo "unknown subcommand: $SUB" >&2; exit 2 ;;
esac