Function buildMessageLookups

src/utils/messages.ts:1170–1340

(
  normalizedMessages: NormalizedMessage[],
  messages: Message[],
)

 * getSiblingToolUseIDs, and hasUnresolvedHooks for each message.
 */
export function buildMessageLookups(
  normalizedMessages: NormalizedMessage[],
  messages: Message[],
): MessageLookups {
  // First pass: group assistant messages by ID and collect all tool use IDs per message
  const toolUseIDsByMessageID = new Map<string, Set<string>>()
  const toolUseIDToMessageID = new Map<string, string>()
  const toolUseByToolUseID = new Map<string, ToolUseBlockParam>()
  for (const msg of messages) {
    if (msg.type === 'assistant') {
      const id = msg.message.id
      let toolUseIDs = toolUseIDsByMessageID.get(id)
      if (!toolUseIDs) {
        toolUseIDs = new Set()
        toolUseIDsByMessageID.set(id, toolUseIDs)
      }
      for (const content of msg.message.content) {
        if (content.type === 'tool_use') {
          toolUseIDs.add(content.id)
          toolUseIDToMessageID.set(content.id, id)
          toolUseByToolUseID.set(content.id, content)
        }
      }
    }
  }

  // Build sibling lookup - each tool use ID maps to all sibling tool use IDs
  const siblingToolUseIDs = new Map<string, Set<string>>()
  for (const [toolUseID, messageID] of toolUseIDToMessageID) {
    siblingToolUseIDs.set(toolUseID, toolUseIDsByMessageID.get(messageID)!)
  }

  // Single pass over normalizedMessages to build progress, hook, and tool result lookups
  const progressMessagesByToolUseID = new Map<string, ProgressMessage[]>()
  const inProgressHookCounts = new Map<string, Map<HookEvent, number>>()
  // Track unique hook names per (toolUseID, hookEvent) to match getResolvedHookCount behavior.
  // A single hook can produce multiple attachment messages (e.g., hook_success + hook_additional_context),
  // so we deduplicate by hookName.
  const resolvedHookNames = new Map<string, Map<HookEvent, Set<string>>>()
  const toolResultByToolUseID = new Map<string, NormalizedMessage>()
  // Track resolved/errored tool use IDs (replaces separate useMemos in Messages.tsx)
  const resolvedToolUseIDs = new Set<string>()
  const erroredToolUseIDs = new Set<string>()

  for (const msg of normalizedMessages) {
    if (msg.type === 'progress') {
      // Build progress messages lookup
      const toolUseID = msg.parentToolUseID
      const existing = progressMessagesByToolUseID.get(toolUseID)
      if (existing) {
        existing.push(msg)
      } else {
        progressMessagesByToolUseID.set(toolUseID, [msg])
      }

      // Count in-progress hooks
      if (msg.data.type === 'hook_progress') {
        const hookEvent = msg.data.hookEvent