#!/usr/bin/env bash
# init-app.sh
# Creates clusters/<cluster>/apps/<application> relative to this script, renders templates,
# updates parent clusters/<cluster>/apps/kustomization.yaml to include the new application,
# and stages changes in Git.

set -euo pipefail

resolve_script_dir() {
  local src="${BASH_SOURCE[0]:-$0}"
  while [ -h "$src" ]; do
    local dir
    dir="$(cd -P "$(dirname "$src")" && pwd)"
    src="$(readlink "$src")"
    [[ "$src" != /* ]] && src="$dir/$src"
  done
  cd -P "$(dirname "$src")" >/dev/null 2>&1
  pwd
}

SCRIPT_DIR="$(resolve_script_dir)"

# Application name
read -r -p "Application name (lowercase, letters/numbers/dashes): " APPLICATION_NAME
APPLICATION_NAME="$(echo "$APPLICATION_NAME" | awk '{$1=$1;print}')"

if [[ -z "$APPLICATION_NAME" ]]; then
  echo "Error: Application name cannot be empty." >&2
  exit 1
fi
if ! [[ "$APPLICATION_NAME" =~ ^[a-z0-9-]+$ ]]; then
  echo "Error: Application name must be lowercase and contain only letters (a-z), numbers (0-9), or dashes (-)." >&2
  exit 1
fi
if [[ "$APPLICATION_NAME" == *"/"* || "$APPLICATION_NAME" == *"\\"* ]]; then
  echo "Error: Application name must not contain path separators (/ or \\)." >&2
  exit 1
fi

# Cluster name
DEFAULT_CLUSTER="artemis"
read -r -p "Cluster name [${DEFAULT_CLUSTER}] (lowercase, letters/numbers/dashes): " CLUSTER_NAME
CLUSTER_NAME="${CLUSTER_NAME:-$DEFAULT_CLUSTER}"
CLUSTER_NAME="$(echo "$CLUSTER_NAME" | awk '{$1=$1;print}')"

if [[ -z "$CLUSTER_NAME" ]]; then
  echo "Error: Cluster name cannot be empty." >&2
  exit 1
fi
if ! [[ "$CLUSTER_NAME" =~ ^[a-z0-9-]+$ ]]; then
  echo "Error: Cluster name must be lowercase and contain only letters (a-z), numbers (0-9), or dashes (-)." >&2
  exit 1
fi
if [[ "$CLUSTER_NAME" == *"/"* || "$CLUSTER_NAME" == *"\\"* ]]; then
  echo "Error: Cluster name must not contain path separators (/ or \\)." >&2
  exit 1
fi

# Description (allows spaces, letters upper/lower, digits, dot, comma)
read -r -p "Description (spaces, letters, numbers, dots, commas): " DESCRIPTION
DESCRIPTION="$(echo "$DESCRIPTION" | sed 's/^[[:space:]]\+//; s/[[:space:]]\+$//')"

if [ -z "$DESCRIPTION" ]; then
  echo "Error: Description cannot be empty." >&2
  exit 1
fi

# Portable validation using grep -Eq (works under sh, dash, bash)
# Allowed chars: A-Za-z0-9 space dot comma
if ! echo "$DESCRIPTION" | grep -Eq '^[A-Za-z0-9 .,]+$'; then
  echo "Error: Description may only contain spaces, letters (A–Z, a–z), numbers (0–9), dots (.), and commas (,)." >&2
  exit 1
fi

TARGET_DIR="${SCRIPT_DIR}/clusters/${CLUSTER_NAME}/apps/${APPLICATION_NAME}"

# Abort if target directory already exists
if [[ -d "$TARGET_DIR" ]]; then
  echo "Error: Directory already exists: $TARGET_DIR" >&2
  exit 1
fi

# Templates
TEMPLATE_DIR="${SCRIPT_DIR}/.templates"
APP_PROJECT_SRC="${TEMPLATE_DIR}/app-project.yaml"
APPLICATION_SRC="${TEMPLATE_DIR}/application.yaml"
KUSTOMIZATION_SRC="${TEMPLATE_DIR}/kustomization.yaml"

missing=false
for f in "$APP_PROJECT_SRC" "$APPLICATION_SRC" "$KUSTOMIZATION_SRC"; do
  if [[ ! -f "$f" ]]; then
    echo "Error: Template not found: ${f}" >&2
    missing=true
  fi
done
if [[ "$missing" == true ]]; then
  exit 1
fi

# Create target directory
mkdir -p "$TARGET_DIR"

# Prepare safe replacements
safe_app_name="${APPLICATION_NAME//\\/\\\\}"
safe_app_name="${safe_app_name//&/\\&}"
safe_description="${DESCRIPTION//\\/\\\\}"
safe_description="${safe_description//&/\\&}"
safe_cluster_name="${CLUSTER_NAME//\\/\\\\}"
safe_cluster_name="${safe_cluster_name//&/\\&}"

# Render app-project.yaml
APP_PROJECT_DEST="${TARGET_DIR}/app-project.yaml"
tmp1="$(mktemp)"
trap 'rm -f "$tmp1" "$tmp2" "$tmp3" "$tmp_parent" "$tmp_norm" "$tmp_slice"' EXIT
sed -e "s/\${APPLICATION_NAME}/${safe_app_name}/g" \
    -e "s/\${DESCRIPTION}/${safe_description}/g" \
    "$APP_PROJECT_SRC" > "$tmp1"
mv "$tmp1" "$APP_PROJECT_DEST"

# Render application.yaml (replace APPLICATION_NAME and CLUSTER_NAME)
APPLICATION_DEST="${TARGET_DIR}/application.yaml"
tmp2="$(mktemp)"
sed -e "s/\${APPLICATION_NAME}/${safe_app_name}/g" \
    -e "s/\${CLUSTER_NAME}/${safe_cluster_name}/g" \
    "$APPLICATION_SRC" > "$tmp2"
mv "$tmp2" "$APPLICATION_DEST"

# Copy kustomization.yaml as-is
KUSTOMIZATION_DEST="${TARGET_DIR}/kustomization.yaml"
cp "$KUSTOMIZATION_SRC" "$KUSTOMIZATION_DEST"

echo "Created: $TARGET_DIR"
echo "Wrote:   $APP_PROJECT_DEST (APPLICATION_NAME='${APPLICATION_NAME}', DESCRIPTION set)"
echo "Wrote:   $APPLICATION_DEST (APPLICATION_NAME='${APPLICATION_NAME}', CLUSTER_NAME='${CLUSTER_NAME}')"
echo "Wrote:   $KUSTOMIZATION_DEST (copied as-is)"

# Update parent kustomization.yaml one level above the new folder
PARENT_KUSTOMIZATION="${SCRIPT_DIR}/clusters/${CLUSTER_NAME}/apps/kustomization.yaml"
if [[ ! -f "$PARENT_KUSTOMIZATION" ]]; then
  echo "Error: Parent kustomization not found: ${PARENT_KUSTOMIZATION}" >&2
  echo "Hint: Ensure a kustomization.yaml exists in clusters/${CLUSTER_NAME}/apps/" >&2
  exit 1
fi

# Normalize CRLF line endings if present
if file "$PARENT_KUSTOMIZATION" | grep -q "CRLF"; then
  tmp_norm="$(mktemp)"
  tr -d '\r' < "$PARENT_KUSTOMIZATION" > "$tmp_norm"
  mv "$tmp_norm" "$PARENT_KUSTOMIZATION"
fi

# If already present, skip
if grep -Eq "^[[:space:]]*-[[:space:]]*${APPLICATION_NAME}[[:space:]]*$" "$PARENT_KUSTOMIZATION"; then
  echo "Parent kustomization.yaml already contains resource '${APPLICATION_NAME}', skipping insertion."
else
  # Determine indentation from the first existing resource item (fallback two spaces)
  indent="$(grep -E '^[[:space:]]*-[[:space:]]' "$PARENT_KUSTOMIZATION" | sed -n '1s/^\([[:space:]]*\)-.*/\1/p')"
  [[ -z "${indent:-}" ]] && indent="  "

  # Work within the most recent 'resources:' block (if any)
  last_res_start_line="$(nl -ba "$PARENT_KUSTOMIZATION" | awk '/^[[:space:]]*[0-9]+\s+resources:[[:space:]]*$/ { line=$1 } END { if (line!="") print line }')"

  if [[ -n "${last_res_start_line:-}" ]]; then
    # Slice parent from resources start to EOF
    tmp_slice="$(mktemp)"
    tail -n +"$last_res_start_line" "$PARENT_KUSTOMIZATION" > "$tmp_slice"

    # In the slice, find last '-' resource line number
    slice_last_line="$(nl -ba "$tmp_slice" \
      | awk '/^[[:space:]]*[0-9]+\s+[[:space:]]*-[[:space:]]/ { print $1 }' \
      | tail -n1)"

    if [[ -n "${slice_last_line:-}" ]]; then
      # Map slice line back to parent absolute line
      abs_last_line=$(( last_res_start_line + slice_last_line - 1 ))

      # Build new file via tmp_parent; avoid arithmetic in command args
      tmp_parent="$(mktemp)"
      head -n "$abs_last_line" "$PARENT_KUSTOMIZATION" > "$tmp_parent"
      printf "%s- %s\n" "$indent" "$APPLICATION_NAME" >> "$tmp_parent"
      next_line=$(( abs_last_line + 1 ))
      tail -n +"$next_line" "$PARENT_KUSTOMIZATION" >> "$tmp_parent"
      mv "$tmp_parent" "$PARENT_KUSTOMIZATION"
      echo "Updated parent kustomization.yaml: appended '${APPLICATION_NAME}' to resources."
    else
      # No items yet → insert directly after the resources key line
      tmp_parent="$(mktemp)"
      head -n "$last_res_start_line" "$PARENT_KUSTOMIZATION" > "$tmp_parent"
      printf "%s- %s\n" "$indent" "$APPLICATION_NAME" >> "$tmp_parent"
      next_line=$(( last_res_start_line + 1 ))
      tail -n +"$next_line" "$PARENT_KUSTOMIZATION" >> "$tmp_parent"
      mv "$tmp_parent" "$PARENT_KUSTOMIZATION"
      echo "Updated parent kustomization.yaml: added first resource '${APPLICATION_NAME}' under resources."
    fi

    rm -f "$tmp_slice"
  else
    # No resources key exists at all → create section at the end ONCE via tmp_parent
    tmp_parent="$(mktemp)"
    cat "$PARENT_KUSTOMIZATION" > "$tmp_parent"
    printf "\nresources:\n%s- %s\n" "$indent" "$APPLICATION_NAME" >> "$tmp_parent"
    mv "$tmp_parent" "$PARENT_KUSTOMIZATION"
    echo "Updated parent kustomization.yaml: created resources section with '${APPLICATION_NAME}'."
  fi
fi

# Stage changes in Git (if inside a Git repo)
if git -C "$SCRIPT_DIR" rev-parse --is-inside-work-tree >/dev/null 2>&1; then
  REPO_ROOT="$(git -C "$SCRIPT_DIR" rev-parse --show-toplevel)"
  REL_TARGET="${TARGET_DIR#$REPO_ROOT/}"
  REL_PARENT="${PARENT_KUSTOMIZATION#$REPO_ROOT/}"
  git -C "$REPO_ROOT" add "$REL_TARGET" "$REL_PARENT"
  echo "Git: staged new directory/files and parent kustomization: $REL_TARGET, $REL_PARENT"
  echo "Next: commit with a message, e.g.:"
  echo "      git -C \"$REPO_ROOT\" commit -m \"feat(${CLUSTER_NAME}): add ${APPLICATION_NAME} app (\"${DESCRIPTION}\") and update kustomization\""
else
  echo "Note: Not inside a Git repository (no .git found). Skipping git add."
fi