import { defineSource } from '@jaspers-ai/sdk'
import { z } from 'zod'


// The IMF's DataMapper, which is the World Economic Outlook and friends behind a plain JSON API.
// No key. One indicator, many countries, a year at a time.

const HOST = 'www.imf.org'
const BASE = `https://${HOST}/external/datamapper/api/v1`

async function get(ctx: { fetch: typeof fetch }, path: string): Promise<unknown> {
  // The IMF refuses a request that does not say who it is.
  const response = await ctx.fetch(`${BASE}/${path}`, {
    headers: { 'User-Agent': 'Jaspers Terminal (https://jsprai.com)', Accept: 'application/json' },
  })
  if (!response.ok) throw new Error(`The IMF answered ${response.status}.`)
  return response.json()
}

export const indicators = defineSource({
  description: 'Every indicator the IMF DataMapper publishes, with its code and what it measures. Read this to find the code an indicator source needs.',
  hosts: [HOST],
  input: z.object({ contains: z.string().optional().describe('Only indicators whose name holds this, like inflation or debt.') }),
  async run({ contains }, ctx) {
    const body = (await get(ctx, 'indicators')) as { indicators: Record<string, { label?: string; unit?: string; source?: string }> }
    const wanted = contains?.trim().toLowerCase()
    const rows = Object.entries(body.indicators)
      .map(([code, one]) => ({ code, label: one.label ?? code, unit: one.unit ?? null, source: one.source ?? null }))
      .filter((one) => !wanted || one.label.toLowerCase().includes(wanted) || one.code.toLowerCase().includes(wanted))
      .sort((a, b) => a.code.localeCompare(b.code))
    return { rows }
  },
})

export const indicator = defineSource({
  description:
    'One IMF indicator for one or more countries, by year. indicator is a DataMapper code like NGDP_RPCH (real GDP growth), PCPIPCH (inflation), GGXWDG_NGDP (government debt to GDP), or LUR (unemployment). Countries are ISO three letter codes. The IMF publishes forecasts as well as history, so later years are projections.',
  hosts: [HOST],
  input: z.object({
    indicator: z.string().default('NGDP_RPCH'),
    countries: z.array(z.string()).default(['USA']).describe('ISO three letter codes, like USA, DEU, CHN.'),
    from: z.number().int().optional().describe('Earliest year.'),
  }),
  async run({ indicator: code, countries, from }, ctx) {
    const wanted = (countries as string[]).map((one) => one.trim().toUpperCase()).filter(Boolean)
    const body = (await get(ctx, `${encodeURIComponent(code.trim().toUpperCase())}/${wanted.join('/')}`)) as {
      values?: Record<string, Record<string, Record<string, number>>>
    }
    const byCountry = body.values?.[code.trim().toUpperCase()]
    if (!byCountry) throw new Error(`The IMF has no indicator called ${code}. Run the indicators source to find its code.`)
    const rows: { country: string; year: number; value: number }[] = []
    for (const [country, years] of Object.entries(byCountry)) {
      // Asking for two countries answers with those two; asking for one answers with every country,
      // so what was asked for is what is kept.
      if (wanted.length > 0 && !wanted.includes(country)) continue
      for (const [year, value] of Object.entries(years)) {
        if (typeof value !== 'number') continue
        if (from && Number(year) < from) continue
        rows.push({ country, year: Number(year), value })
      }
    }
    rows.sort((a, b) => a.year - b.year || a.country.localeCompare(b.country))
    return { indicator: code, rows }
  },
})