import type { ChannelPoint, DailyPoint, DayKey, Event, EventType, Kpis, Lead } from "@/lib/domain"
import { clamp, toDayKey } from "@/lib/time"

export function computeKpis(args: { events: Event[]; leads: Lead[] }): Kpis {
  const uv = countUv(args.events)
  const clicks = countType(args.events, "click")
  const submits = countType(args.events, "submit")
  const claims = countType(args.events, "claim")
  const redeems = countType(args.events, "redeem")
  const submitRate = uv ? submits / uv : 0
  const redeemRate = submits ? redeems / submits : 0
  return { uv, clicks, submits, claims, redeems, submitRate, redeemRate }
}

export function dailySeries(args: { events: Event[]; days: number }): DailyPoint[] {
  const map = new Map<DayKey, DailyPoint>()
  const types: EventType[] = ["view", "submit", "redeem"]
  for (const e of args.events) {
    if (!types.includes(e.type)) continue
    const day = toDayKey(e.ts)
    const cur = map.get(day) ?? { day, uv: 0, submits: 0, redeems: 0 }
    if (e.type === "view") cur.uv += 1
    if (e.type === "submit") cur.submits += 1
    if (e.type === "redeem") cur.redeems += 1
    map.set(day, cur)
  }

  const keys = Array.from(map.keys()).sort((a, b) => a.localeCompare(b))
  const tail = keys.slice(Math.max(0, keys.length - args.days))
  return tail.map((k) => map.get(k)!).map((p) => ({ ...p, uv: clamp(p.uv, 0, 999999) }))
}

export function channelSeries(args: { events: Event[]; max: number }): ChannelPoint[] {
  const map = new Map<string, ChannelPoint>()
  for (const e of args.events) {
    const channel = (e.meta?.utm_source as string | undefined) ?? "direct"
    const cur = map.get(channel) ?? { channel, uv: 0, submits: 0, redeems: 0 }
    if (e.type === "view") cur.uv += 1
    if (e.type === "submit") cur.submits += 1
    if (e.type === "redeem") cur.redeems += 1
    map.set(channel, cur)
  }

  return Array.from(map.values())
    .sort((a, b) => b.uv - a.uv)
    .slice(0, args.max)
}

export function countUv(events: Event[]) {
  const views = events.filter((e) => e.type === "view")
  return views.length
}

export function countType(events: Event[], type: EventType) {
  return events.reduce((acc, e) => acc + (e.type === type ? 1 : 0), 0)
}