import type { AgentModelDefinition } from '@server/server/agent/agent-sdk-types'

export function normalizeModelId(modelId: string | null | undefined): string | null {
  const normalized = typeof modelId === 'string' ? modelId.trim() : ''
  if (!normalized || normalized.toLowerCase() === 'default') {
    return null
  }
  return normalized
}

export function resolveAgentModelSelection(input: {
  models: AgentModelDefinition[] | null
  runtimeModelId: string | null | undefined
  configuredModelId: string | null | undefined
  explicitThinkingOptionId: string | null | undefined
}) {
  const { models, runtimeModelId, configuredModelId, explicitThinkingOptionId } = input
  const normalizedRuntimeModelId = normalizeModelId(runtimeModelId)
  const normalizedConfiguredModelId = normalizeModelId(configuredModelId)
  const preferredModelId = normalizedRuntimeModelId ?? normalizedConfiguredModelId
  const selectedModel =
    models && preferredModelId ? models.find((model) => model.id === preferredModelId) ?? null : null

  const activeModelId = selectedModel?.id ?? preferredModelId ?? null
  const displayModel = selectedModel?.label ?? preferredModelId ?? 'Auto'

  const thinkingOptions = selectedModel?.thinkingOptions ?? null
  const selectedThinkingId =
    explicitThinkingOptionId && explicitThinkingOptionId !== 'default'
      ? explicitThinkingOptionId
      : selectedModel?.defaultThinkingOptionId ?? null
  const selectedThinking = thinkingOptions?.find((option) => option.id === selectedThinkingId) ?? null
  const displayThinking =
    selectedThinking?.label ??
    (selectedThinkingId === 'default' ? 'Model default' : selectedThinkingId ?? 'auto')

  return {
    selectedModel,
    activeModelId,
    displayModel,
    thinkingOptions,
    selectedThinkingId,
    displayThinking,
  }
}