#!/bin/bash

FEED_TITLE="My RSS Feed"
FEED_LINK="https://example.com"
FEED_DESC="Example RSS Feed Description"
FEED_LANG="en-us"

ITEMS_FILE="rss_items.json"
RSS_FILE="rss_feed.xml"

if ! command -v jq &> /dev/null; then
  echo "Error: jq is required but not installed. Please install jq first."
  exit 1
fi

[ ! -f "$ITEMS_FILE" ] && echo "[]" > "$ITEMS_FILE"

function generate_rss() {
  local lastBuildDate
  lastBuildDate=$(date -R)

  {
    echo '<?xml version="1.0" encoding="UTF-8"?>'
    echo '<rss version="2.0">'
    echo '  <channel>'
    echo "    <title>$FEED_TITLE</title>"
    echo "    <link>$FEED_LINK</link>"
    echo "    <description>$FEED_DESC</description>"
    echo "    <language>$FEED_LANG</language>"
    echo "    <lastBuildDate>$lastBuildDate</lastBuildDate>"

    jq -c '.[]' "$ITEMS_FILE" | while read -r item; do
      title=$(echo "$item" | jq -r '.title')
      description=$(echo "$item" | jq -r '.description')
      body=$(echo "$item" | jq -r '.body')
      link=$(echo "$item" | jq -r '.link')
      pubDate=$(echo "$item" | jq -r '.pubDate')
      guid=$(echo "$item" | jq -r '.guid')

      echo "    <item>"
      echo "      <title><![CDATA[$title]]></title>"
      if [ -n "$link" ]; then
        echo "      <link>$link</link>"
      fi
      echo "      <description><![CDATA[$description<br><br>$body]]></description>"
      echo "      <pubDate>$pubDate</pubDate>"
      echo "      <guid isPermaLink=\"false\">$guid</guid>"
      echo "    </item>"
    done

    echo '  </channel>'
    echo '</rss>'
  } > "$RSS_FILE"
}

function list_items() {
  local count
  count=$(jq length "$ITEMS_FILE")
  if [ "$count" -eq 0 ]; then
    echo "No items found."
    return
  fi
  echo "Current RSS items:"
  jq -r '.[] | "\(.title)"' "$ITEMS_FILE" | nl
}

function read_input() {
  local prompt=$1
  local default=$2
  local result

  if [ -z "$default" ]; then
    read -rp "$prompt: " result
  else
    read -rp "$prompt [$default]: " result
    result=${result:-$default}
  fi
  echo "$result"
}

function add_item() {
  local title description body link pubDate guid

  title=$(read_input "Enter Title")
  description=$(read_input "Enter Description")
  body=$(read_input "Enter Body")
  link=$(read_input "Enter Link (full URL, or leave empty for no link)" "")


  if [ -n "$link" ] && [[ ! "$link" =~ ^https?:// ]]; then
    echo "Warning: Link should start with http:// or https://"
  fi

  pubDate=$(date -R)
  guid=$(echo -n "$title$pubDate" | md5sum | cut -d ' ' -f1)

  jq --arg t "$title" --arg d "$description" --arg b "$body" --arg l "$link" --arg p "$pubDate" --arg g "$guid" \
    '. + [{"title": $t, "description": $d, "body": $b, "link": $l, "pubDate": $p, "guid": $g}]' "$ITEMS_FILE" > tmp.json && mv tmp.json "$ITEMS_FILE"

  generate_rss
  echo "Item added successfully."
}

function update_item() {
  list_items
  local count index new_title new_desc new_body new_link pubDate guid

  count=$(jq length "$ITEMS_FILE")
  if [ "$count" -eq 0 ]; then
    return
  fi

  read -rp "Enter item number to update: " num
  if ! [[ "$num" =~ ^[0-9]+$ ]] || [ "$num" -lt 1 ] || [ "$num" -gt "$count" ]; then
    echo "Invalid item number."
    return
  fi
  index=$((num - 1))

  local old_title old_desc old_body old_link
  old_title=$(jq -r ".[${index}].title" "$ITEMS_FILE")
  old_desc=$(jq -r ".[${index}].description" "$ITEMS_FILE")
  old_body=$(jq -r ".[${index}].body" "$ITEMS_FILE")
  old_link=$(jq -r ".[${index}].link" "$ITEMS_FILE")

  new_title=$(read_input "New Title" "$old_title")
  new_desc=$(read_input "New Description" "$old_desc")
  new_body=$(read_input "New Body" "$old_body")
  new_link=$(read_input "New Link (full URL, or leave empty for no link)" "$old_link")

  if [ -n "$new_link" ] && [[ ! "$new_link" =~ ^https?:// ]]; then
    echo "Warning: Link should start with http:// or https://"
  fi

  pubDate=$(date -R)
  guid=$(echo -n "$new_title$pubDate" | md5sum | cut -d ' ' -f1)

  jq ".[${index}] |= {title: \"$new_title\", description: \"$new_desc\", body: \"$new_body\", link: \"$new_link\", pubDate: \"$pubDate\", guid: \"$guid\"}" "$ITEMS_FILE" > tmp.json && mv tmp.json "$ITEMS_FILE"

  generate_rss
  echo "Item updated successfully."
}

function delete_item() {
  list_items
  local count index

  count=$(jq length "$ITEMS_FILE")
  if [ "$count" -eq 0 ]; then
    return
  fi

  read -rp "Enter item number to delete: " num
  if ! [[ "$num" =~ ^[0-9]+$ ]] || [ "$num" -lt 1 ] || [ "$num" -gt "$count" ]; then
    echo "Invalid item number."
    return
  fi
  index=$((num - 1))

  jq "del(.[${index}])" "$ITEMS_FILE" > tmp.json && mv tmp.json "$ITEMS_FILE"

  generate_rss
  echo "Item deleted successfully."
}

function main_menu() {
  echo
  echo "===== RSS Feed Manager ====="
  echo "1) List items"
  echo "2) Add item"
  echo "3) Update item"
  echo "4) Delete item"
  echo "5) Generate RSS XML now"
  echo "6) Exit"
  read -rp "Choose an option: " opt
  case $opt in
    1) list_items ;;
    2) add_item ;;
    3) update_item ;;
    4) delete_item ;;
    5) generate_rss; echo "RSS XML generated at $RSS_FILE" ;;
    6) exit 0 ;;
    *) echo "Invalid option." ;;
  esac
}

if [ ! -s "$RSS_FILE" ]; then
  generate_rss
fi

while true; do
  main_menu
done