#!/usr/bin/env bash
# Safety settings: exit on errors, treat unset variables as errors, and catch pipeline failures
set -euo pipefail

# Find and navigate to the git repo root (or current dir if not in a repo) so file paths work correctly regardless of where the commit command is run
ROOT="$(git rev-parse --show-toplevel 2>/dev/null || echo ".")"
cd "$ROOT"

resolve_template() {
  local tmpl="$1" rel_path="$2"
  local today dirpath basename name ext feature_id stage
  today="$(date +%F)"
  dirpath="$(dirname "$rel_path")"
  basename="$(basename "$rel_path")"
  name="${basename%.*}"
  ext="${basename##*.}"
  feature_id=""
  stage=""
  feature_id="$(echo "$rel_path" | sed -n 's|.*Docs/features/\(FR_[^/]*\).*|\1|p')"
  stage="$(echo "$basename" | sed -n 's/^\([A-Za-z0-9_-]\+\)\.discussion\.md$/\1|p')"
  echo "$tmpl" \
    | sed -e "s_{date}_$today_g" \
          -e "s_{rel}_$rel_path_g" \
          -e "s_{dir}_$dirpath_g" \
          -e "s_{basename}_$basename_g" \
          -e "s_{name}_$name_g" \
          -e "s_{ext}_$ext_g" \
          -e "s_{feature_id}_$feature_id_g" \
          -e "s_{stage}_$stage_g"
}

# Helper function to apply a patch with 3-way merge fallback
apply_patch_with_3way() {
  local patch_file="$1"
  local target_file="$2"

  if [ ! -f "$patch_file" ]; then
    echo >&2 "[pre-commit] Error: Patch file not found: $patch_file"
    return 1
  fi

  # Attempt 3-way apply
  if git apply --index --3way --recount --whitespace=nowarn "$patch_file"; then
    echo >&2 "[pre-commit] Applied patch to $target_file with 3-way merge."
  elif git apply --index "$patch_file"; then
    echo >&2 "[pre-commit] Applied patch to $target_file with strict apply (3-way failed)."
  else
    echo >&2 "[pre-commit] Error: Failed to apply patch to $target_file."
    echo >&2 "           Manual intervention may be required."
    return 1
  fi
  return 0
}

# Helper function to check if changes to a discussion file are append-only
check_append_only_discussion() {
  local disc_file="$1"
  local diff_output

  # Get the cached diff for the discussion file
  diff_output=$(git diff --cached "$disc_file")

  # Check if there are any deletions or modifications to existing lines
  # This is a simplified check; a more robust solution would parse hunks
  if echo "$diff_output" | grep -E "^-[^-]" | grep -Ev "^--- a/" | grep -Ev "^\+\+\+ b/"; then
    echo >&2 "[pre-commit] Error: Deletions or modifications detected in existing lines of $disc_file."
    echo >&2 "           Discussion files must be append-only, except for allowed header fields."
    return 1
  fi

  # Check for modifications to header fields (status, timestamps, feature_id, stage_id)
  # This is a basic check and might need refinement based on actual header structure
  # For now, we'll allow changes to lines that look like header fields.
  # A more robust solution would parse YAML front matter.
  local header_modified=0
  if echo "$diff_output" | grep -E "^[-+]" | grep -E "^(status|created|updated|feature_id|stage_id):" > /dev/null; then
    header_modified=1
  fi

  # If there are additions, ensure they are at the end of the file, or are allowed header modifications
  # This is a very basic check. A more advanced check would compare line numbers.
  # For now, if there are additions and no deletions/modifications to body, we assume append-only.
  if echo "$diff_output" | grep -E "^\+[^+]" | grep -Ev "^\+\+\+ b/" > /dev/null && [ "$header_modified" -eq 0 ]; then
    : # Placeholder for more robust append-only check
  fi

  return 0
}

# -------- collect staged files ----------
# Get list of staged added/modified files into STAGED array, exit early if none found
mapfile -t STAGED < <(git diff --cached --name-only --diff-filter=AM || true)
[ "${#STAGED[@]}" -eq 0 ] && exit 0

# -------- ensure discussion summaries exist (companion files) ----------
# Create and auto-stage a summary template file for any discussion file that doesn't already have one
ensure_summary() {
  local disc="$1"
  local dir; dir="$(dirname "$disc")"
  local sum="$dir/$(basename "$disc" .md).sum.md"
  local template_path="assets/templates/feature.discussion.sum.md"

  if [ ! -f "$sum" ]; then
    # Copy the template content directly
    cat "$template_path" > "$sum"
    git add "$sum"
  fi
}

# Process each staged discussion file and ensure it has a summary
for f in "${STAGED[@]}"; do
  case "$f" in
    Docs/features/*/discussions/*.discussion.md) 
      ensure_summary "$f"
      if ! check_append_only_discussion "$f"; then
        exit 1 # Exit with error if append-only check fails
      fi
      ;;
  esac
done

# -------- orchestration (non-blocking status) ----------

# -------- automation runner (AI outputs) ----------
if [ -f "automation/runner.py" ]; then
  if ! python3 -m automation.runner; then
    echo "[pre-commit] automation.runner failed" >&2
    exit 1
  fi
fi

# -------- orchestration (non-blocking status) ----------
# NOTE: automation/workflow.py provides non-blocking vote status reporting.
# It parses VOTE: lines from staged discussion files and prints a summary.
# Run workflow status check if available, but don't block commit if it fails.
if [ -x "automation/workflow.py" ]; then
  python3 automation/workflow.py --status || true
fi

exit 0