import { describe, expect, it } from 'vitest'
import type { PositionUpdate } from '@vpp/domain'
import { CascadeViolation, LedgerConcurrencyError, LedgerService } from '../src/ledger.js'

const clock = () => '2026-03-14T08:00:00Z'

const monthlyContract: PositionUpdate = {
  id: 'pos-monthly',
  timescale: 'MONTHLY',
  period: '2026-03',
  kind: 'CONTRACT',
  energy_mwh: '37200.0', // 1200 MWh/day over 31 days
  curve: null,
  source_ref: 'contract-2026-03-001',
  expected_version: 0,
}

const daBid = (energy: string, expectedVersion: number): PositionUpdate => ({
  id: `pos-da-${energy}`,
  timescale: 'DAY_AHEAD',
  period: '2026-03-15',
  kind: 'BID_SUBMITTED',
  energy_mwh: energy,
  curve: null,
  source_ref: 'b'.repeat(64),
  expected_version: expectedVersion,
})

const makeLedger = () => new LedgerService({ daMonthlyDeviationBand: '0.05', clock })

describe('constraint cascade (P7): monthly position bounds day-ahead bids', () => {
  it('accepts a bid within the ±5% band of the pro-rata daily share', () => {
    const ledger = makeLedger()
    ledger.append(monthlyContract)
    const view = ledger.append(daBid('1240.0', 1)) // daily share 1200, band [1140, 1260]
    expect(view.version).toBe(2)
  })

  it('rejects a bid above the band', () => {
    const ledger = makeLedger()
    ledger.append(monthlyContract)
    expect(() => ledger.append(daBid('1300.0', 1))).toThrow(CascadeViolation)
  })

  it('rejects a bid below the band', () => {
    const ledger = makeLedger()
    ledger.append(monthlyContract)
    expect(() => ledger.append(daBid('1000.0', 1))).toThrow(CascadeViolation)
  })

  it('rejects a day-ahead bid with no monthly anchor (no default-allow)', () => {
    const ledger = makeLedger()
    expect(() => ledger.append(daBid('1200.0', 0))).toThrow(CascadeViolation)
  })
})

describe('optimistic concurrency', () => {
  it('rejects an append against a stale version', () => {
    const ledger = makeLedger()
    ledger.append(monthlyContract)
    expect(() => ledger.append({ ...monthlyContract, id: 'pos-2', expected_version: 0 })).toThrow(
      LedgerConcurrencyError,
    )
  })
})

describe('views', () => {
  it('filters by timescale and stamps recorded_at from the injected clock', () => {
    const ledger = makeLedger()
    ledger.append(monthlyContract)
    ledger.append(daBid('1200.0', 1))
    const monthly = ledger.viewByTimescale('MONTHLY')
    expect(monthly).toHaveLength(1)
    expect(monthly[0]!.recorded_at).toBe(clock())
    expect(ledger.viewByTimescale('DAY_AHEAD')).toHaveLength(1)
  })
})

describe('dayAheadBounds: the cascade band handed to the bid optimizer', () => {
  it('returns the same band checkCascade enforces, stamped with the ledger version', () => {
    const ledger = makeLedger()
    ledger.append(monthlyContract)
    expect(ledger.dayAheadBounds('2026-03-15')).toEqual({
      ledger_version: 1,
      daily_energy_min_mwh: '1140',
      daily_energy_max_mwh: '1260',
    })
    // A bid exactly at each bound is accepted by append — bounds are inclusive.
    ledger.append(daBid('1140', 1))
    ledger.append({ ...daBid('1260', 2), id: 'pos-da-max' })
  })

  it('throws when there is no monthly anchor', () => {
    expect(() => makeLedger().dayAheadBounds('2026-03-15')).toThrow(CascadeViolation)
  })
})