/** The AI contract additions (see contract.md): runs, review rows, the approve gate. */
export type Band = 'green' | 'amber' | 'red' | 'blank' | 'unscored'
export type RunStatus = 'pending' | 'queued' | 'running' | 'done' | 'failed'
export type Run = {
  job_id: string
  document: string
  status: RunStatus
  model: string
  pages_done: number
  pages_total: number
  summary: Record<Band, number> | null // null until the run is done
  approved: boolean
  error: string | null
}
export type ReviewRow = {
  row_id: number
  field: string
  value: string | null
  band: Band
  score: number | null
  reason: string | null
  verified: boolean
  corrected_value: string | null
}

/** One run on the cost page. total_cost is null when the run recorded no token usage (unpriced). */
export type RoiRun = {
  job_id: string
  document: string
  created_at: string // ISO, UTC
  model: string
  input_tokens: number | null
  output_tokens: number | null
  thinking_tokens: number | null
  total_cost: number | null // USD
}
export type Pricing = { source: string; as_of: string }

export const BUSY: RunStatus[] = ['queued', 'running'] // polled every 1.5s while in one of these

/** Legend order, label, and the colour token. Band colours are semantic: never on buttons or headings. */
export const BANDS: { band: Band; label: string; colour: string }[] = [
  { band: 'green', label: 'Clean ≥0.95', colour: 'var(--clean)' },
  { band: 'amber', label: 'Check 0.90–0.95', colour: 'var(--verify)' },
  { band: 'red', label: 'Review <0.90', colour: 'var(--review)' },
  { band: 'blank', label: 'Missing (required)', colour: 'var(--absent)' },
  { band: 'unscored', label: 'Unscored', colour: 'var(--absent)' },
]
export const CAVEAT = 'Colour reflects print clarity, not correctness. A cleanly printed value can still be misread.'

async function req<T>(path: string, init?: RequestInit): Promise<T> {
  const res = await fetch(API_BASE + path, { ...init, headers: { 'Content-Type': 'application/json' } })
  if (!res.ok) {
    // The server says why it refused (the approve gate answers 409 with the count).
    const body = await res.json().catch(() => null)
    throw new Error(body?.detail ?? `${res.status} ${res.statusText}`)
  }
  return res.json()
}

export const ai = {
  runs: () => req<{ runs: Run[] }>('/runs'),
  run: (id: string) => req<Run>(`/runs/${id}`),
  rows: (id: string) => req<{ rows: ReviewRow[] }>(`/runs/${id}/review`),
  patchRow: (rowId: number, body: { corrected_value?: string | null; verified: boolean }) =>
    req<ReviewRow>(`/review/${rowId}`, { method: 'PATCH', body: JSON.stringify(body) }),
  verifyRemaining: (id: string) => req<{ verified: number }>(`/runs/${id}/verify-remaining`, { method: 'POST' }),
  approve: (id: string) => req<{ ok: boolean }>(`/runs/${id}/approve`, { method: 'POST' }),
  roi: () => req<{ runs: RoiRun[]; pricing: Pricing }>('/roi'),
  documentUrl: (id: string) => `${API_BASE}/runs/${id}/document`,
}