#!/usr/bin/env bash
# Extract one task's full text from an implementation plan into a file the
# implementer reads in one call, so the task text never has to be pasted
# through the controller's context.
#
# Usage: task-brief PLAN_FILE TASK_NUMBER [OUTFILE]
# Default OUTFILE: <git-dir>/sdd/task-<N>-brief.md — unique per repo
# instance, so concurrent sessions cannot collide.
set -euo pipefail

if [ $# -lt 2 ] || [ $# -gt 3 ]; then
  echo "usage: task-brief PLAN_FILE TASK_NUMBER [OUTFILE]" >&2
  exit 2
fi

plan=$1
n=$2
[ -f "$plan" ] || { echo "no such plan file: $plan" >&2; exit 2; }

if [ $# -eq 3 ]; then
  out=$3
else
  dir=$(git rev-parse --git-path sdd)
  mkdir -p "$dir"
  dir=$(cd "$dir" && pwd)
  out="$dir/task-${n}-brief.md"
fi

awk -v n="$n" '
  /^```/ { infence = !infence }
  !infence && /^#+[ \t]+Task[ \t]+[0-9]+/ {
    intask = ($0 ~ ("^#+[ \t]+Task[ \t]+" n "([^0-9]|$)"))
  }
  intask { print }
' "$plan" > "$out"

if [ ! -s "$out" ]; then
  echo "task ${n} not found in ${plan} (no heading matching 'Task ${n}')" >&2
  exit 3
fi

echo "wrote ${out}: $(wc -l < "$out" | tr -d ' ') lines"