import { valueMap } from 'cosmokit'
import * as yaml from 'js-yaml'

// eslint-disable-next-line no-new-func
export const evaluate = new Function('ctx', 'expr', `
  with (ctx) {
    return eval(expr)
  }
`) as ((ctx: object, expr: string) => any)

export function interpolate(ctx: object, value: any) {
  if (isJsExpr(value)) {
    return evaluate(ctx, value.__jsExpr)
  } else if (!value || typeof value !== 'object') {
    return value
  } else if (Array.isArray(value)) {
    return value.map(item => interpolate(ctx, item))
  } else {
    return valueMap(value, item => interpolate(ctx, item))
  }
}

function isJsExpr(value: any): value is JsExpr {
  return value instanceof Object && '__jsExpr' in value
}

export interface JsExpr {
  __jsExpr: string
}

export const JsExpr = new yaml.Type('tag:yaml.org,2002:js', {
  kind: 'scalar',
  resolve: (data) => typeof data === 'string',
  construct: (data) => ({ __jsExpr: data }),
  predicate: isJsExpr,
  represent: (data) => data['__jsExpr'],
})