import { describe, it, expect } from 'vitest'
import {
  RATE_WINDOW_MS,
  RATE_MAX_ATTEMPTS,
  checkAndRecordAttempt,
} from '../../skills/data-portal/template/functions/api/_lib/ratelimit'
import type { D1Database } from '../../skills/data-portal/template/functions/api/_lib/types'

// Minimal D1 fake: one row per (scope, windowStart), matching the schema's
// unique index. The INSERT ... ON CONFLICT DO UPDATE is modelled as an upsert.
function fakeDb(seed: Array<{ scope: string; windowStart: number; count: number }> = []) {
  const rows = [...seed]
  const db: D1Database = {
    prepare(query: string) {
      let bound: unknown[] = []
      const stmt = {
        bind(...v: unknown[]) {
          bound = v
          return stmt
        },
        async run() {
          if (/INSERT/i.test(query)) {
            const [scope, windowStart] = bound as [string, number]
            const hit = rows.find((r) => r.scope === scope && r.windowStart === windowStart)
            if (hit) hit.count++
            else rows.push({ scope, windowStart, count: 1 })
          }
          return { meta: { changes: 1 } }
        },
        async all() {
          return { results: [] }
        },
        async first<T>() {
          const [scope, windowStart] = bound as [string, number]
          const hit = rows.find((r) => r.scope === scope && r.windowStart === windowStart)
          return (hit ? { count: hit.count } : null) as T | null
        },
      }
      return stmt
    },
  }
  return { db, rows }
}

describe('checkAndRecordAttempt', () => {
  it('allows the first attempt in a window', async () => {
    const { db } = fakeDb()
    expect(await checkAndRecordAttempt(db, 'alice', 1_000_000)).toEqual({ allowed: true, count: 1 })
  })

  it('allows up to the cap', async () => {
    const w = Math.floor(1_000_000 / RATE_WINDOW_MS) * RATE_WINDOW_MS
    const { db } = fakeDb([{ scope: 'alice', windowStart: w, count: RATE_MAX_ATTEMPTS - 1 }])
    expect((await checkAndRecordAttempt(db, 'alice', 1_000_000)).allowed).toBe(true)
  })

  it('denies past the cap', async () => {
    const w = Math.floor(1_000_000 / RATE_WINDOW_MS) * RATE_WINDOW_MS
    const { db } = fakeDb([{ scope: 'alice', windowStart: w, count: RATE_MAX_ATTEMPTS }])
    const res = await checkAndRecordAttempt(db, 'alice', 1_000_000)
    expect(res.allowed).toBe(false)
    expect(res.count).toBeGreaterThan(RATE_MAX_ATTEMPTS)
  })

  it('starts a fresh count in the next window', async () => {
    const w = Math.floor(1_000_000 / RATE_WINDOW_MS) * RATE_WINDOW_MS
    const { db } = fakeDb([{ scope: 'alice', windowStart: w, count: RATE_MAX_ATTEMPTS }])
    const later = 1_000_000 + RATE_WINDOW_MS
    expect((await checkAndRecordAttempt(db, 'alice', later)).allowed).toBe(true)
  })

  it('scopes counts independently per person', async () => {
    const w = Math.floor(1_000_000 / RATE_WINDOW_MS) * RATE_WINDOW_MS
    const { db } = fakeDb([{ scope: 'alice', windowStart: w, count: RATE_MAX_ATTEMPTS }])
    expect((await checkAndRecordAttempt(db, 'bob', 1_000_000)).allowed).toBe(true)
  })
})