import { requireStageTwoUser, stageTwoApiError, stageTwoDatabase } from '~/server/utils/stage-two-supabase'

interface UsageRow {
  campaign_id: string | null
  request_kind: string
  input_tokens: number
  output_tokens: number
  cost_usd: number | string
  latency_ms: number | null
  created_at: string
}

export default defineEventHandler(async (event) => {
  try {
    const user = await requireStageTwoUser(event)
    const since = new Date()
    since.setUTCDate(since.getUTCDate() - 30)
    const today = new Date()
    today.setUTCHours(0, 0, 0, 0)
    const [usage, quotaEvents] = await Promise.all([
      stageTwoDatabase<UsageRow[]>(
        `ai_usage?select=campaign_id,request_kind,input_tokens,output_tokens,cost_usd,latency_ms,created_at&user_id=eq.${user.id}&created_at=gte.${encodeURIComponent(since.toISOString())}&order=created_at.desc&limit=1000`,
      ),
      stageTwoDatabase<Array<{ created_at: string }>>(
        `ai_quota_events?select=created_at&user_id=eq.${user.id}&created_at=gte.${encodeURIComponent(today.toISOString())}`,
      ),
    ])
    const campaignIds = [...new Set(usage.flatMap(row => row.campaign_id ? [row.campaign_id] : []))]
    const campaigns = campaignIds.length
      ? await stageTwoDatabase<Array<{ id: string; title: string }>>(`campaigns?select=id,title&id=in.(${campaignIds.join(',')})`)
      : []
    const campaignNames = new Map(campaigns.map(campaign => [campaign.id, campaign.title]))
    const summarize = (rows: UsageRow[]) => {
      const latencies = rows.flatMap(row => row.latency_ms === null ? [] : [Number(row.latency_ms)])
      return {
        requests: rows.length,
        inputTokens: rows.reduce((sum, row) => sum + Number(row.input_tokens), 0),
        outputTokens: rows.reduce((sum, row) => sum + Number(row.output_tokens), 0),
        costUsd: rows.reduce((sum, row) => sum + Number(row.cost_usd), 0),
        averageLatencyMs: latencies.length ? Math.round(latencies.reduce((sum, value) => sum + value, 0) / latencies.length) : 0,
      }
    }
    const grouped = new Map<string, UsageRow[]>()
    for (const row of usage) {
      const key = row.campaign_id ?? 'coauthor'
      grouped.set(key, [...(grouped.get(key) ?? []), row])
    }
    return {
      periodDays: 30,
      quota: { usedToday: quotaEvents.length, dailyRequestLimit: 60, dailyTokenLimit: 250000 },
      totals: summarize(usage),
      groups: [...grouped].map(([id, rows]) => ({
        id,
        label: id === 'coauthor' ? 'World coauthor' : campaignNames.get(id) ?? 'Private campaign',
        ...summarize(rows),
      })).sort((left, right) => right.costUsd - left.costUsd),
    }
  } catch (error) {
    stageTwoApiError(error)
  }
})