import { afterAll, beforeAll, describe, expect, it } from 'vitest'
import { openRelayDatabase, type RelayDatabase } from './database.js'

const databaseUrl = process.env.ORCA_RELAY_TEST_POSTGRES_URL
const describePostgres = databaseUrl ? describe : describe.skip
const applicationName = 'orca-relay/statement-timeout-postgres'

describePostgres('PostgreSQL statement deadline', () => {
  const databases: RelayDatabase[] = []

  beforeAll(async () => {
    databases.push(await openRelayDatabase({ databaseUrl, dataDir: '' }))
  })

  afterAll(async () => {
    for (const database of databases) await database.close()
  })

  it('serves requests under the configured deadline', async () => {
    const database = await openRelayDatabase({ databaseUrl, dataDir: '', statementTimeoutMs: 300 })
    databases.push(database)

    expect(await database.query(`SELECT current_setting('statement_timeout') AS statement_timeout`)).toEqual([
      { statement_timeout: '300ms' }
    ])
  })

  // Why: a real 57014 aborts the transaction exactly as a lock timeout does. If
  // it escapes the bounded retry it becomes a failed assignment instead of a
  // slow one.
  it('retries a real statement timeout on a fresh client', async () => {
    const database = await openRelayDatabase({ databaseUrl, dataDir: '', statementTimeoutMs: 300 })
    databases.push(database)
    let attempts = 0

    const result = await database.transaction(async (transaction) => {
      attempts += 1
      if (attempts === 1) await transaction.query(`SELECT pg_sleep(2)`)
      return attempts
    })

    expect(result).toBe(2)
  }, 15_000)

  // Why: DDL runs on its own untimed connection. relay_invites carries a
  // CREATE INDEX IF NOT EXISTS, which (unlike CREATE TABLE IF NOT EXISTS)
  // really does queue behind an ACCESS EXCLUSIVE lock on the table.
  it('applies the schema behind a held ACCESS EXCLUSIVE lock', async () => {
    let releaseTable!: () => void
    const tableReleased = new Promise<void>((resolve) => {
      releaseTable = resolve
    })
    let tableHeld!: () => void
    const tableHeldPromise = new Promise<void>((resolve) => {
      tableHeld = resolve
    })
    const holder = databases[0]!.transaction(async (transaction) => {
      await transaction.query(`LOCK TABLE relay_invites IN ACCESS EXCLUSIVE MODE`)
      tableHeld()
      await tableReleased
    })
    await tableHeldPromise

    const opening = openRelayDatabase({
      databaseUrl,
      dataDir: '',
      applicationName,
      // Far too short for a blocked DDL; the serving pool wears it, the schema
      // connection must not.
      statementTimeoutMs: 200
    })
    const blockedOnSchemaConnection = async (): Promise<boolean> => {
      const deadline = Date.now() + 4_000
      while (Date.now() < deadline) {
        const rows = await databases[0]!.query(
          `SELECT count(*) AS waiting FROM pg_stat_activity
           WHERE datname = current_database() AND wait_event_type = 'Lock'
             AND application_name = ?`,
          [`${applicationName}/schema`]
        )
        if (Number(rows[0]!.waiting) > 0) return true
        await new Promise((resolve) => setTimeout(resolve, 10))
      }
      return false
    }
    const blocked = await blockedOnSchemaConnection()
    releaseTable()
    await holder

    const database = await opening
    databases.push(database)
    expect(blocked).toBe(true)
    // The serving pool still carries the short deadline it was opened with.
    expect(await database.query(`SELECT current_setting('statement_timeout') AS statement_timeout`)).toEqual([
      { statement_timeout: '200ms' }
    ])
  }, 15_000)
})