import { Request, Response } from "express"
import { Attribute, Attributes } from "./metadata"

export function buildAndCheckId<ID>(req: Request, res: Response, keys?: Attribute[]): ID | undefined {
  const id = buildId<ID>(req, keys)
  if (!id) {
    res.status(400).end("invalid parameters")
    return undefined
  }
  return id
}
export function buildId<T>(req: Request, attrs?: Attribute[]): T | undefined {
  if (!attrs || attrs.length === 0) {
    const id = req.params["id"] as string
    if (id && id.length > 0) {
      return id as any
    }
    return undefined
  }
  if (attrs && attrs.length === 1) {
    let id = req.params["id"] as string
    const n = attrs[0].name
    if ((!id || id.length === 0) && n && n.length > 0) {
      id = req.params[n] as string
    }
    if (id && id.length > 0) {
      if (attrs[0].type === "integer" || attrs[0].type === "number") {
        if (isNaN(id as any)) {
          return undefined
        }
        const v = parseFloat(id)
        return v as any
      }
      return id as any
    }
  }
  const ids: any = {}
  for (const attr of attrs) {
    if (!attr.name) {
      return undefined
    }
    const v = req.params[attr.name]
    if (!v) {
      return undefined
    }
    if (attr.type === "integer" || attr.type === "number") {
      if (isNaN(v as any)) {
        return undefined
      }
      ids[attr.name] = parseFloat(v as string)
    } else {
      ids[attr.name] = v
    }
    return ids
  }
}
export function buildKeys(attrs: Attributes): Attribute[] | undefined {
  if (!attrs) {
    return undefined
  }
  const keys: string[] = Object.keys(attrs)
  const ats: Attribute[] = []
  for (const key of keys) {
    const attr: Attribute = attrs[key]
    if (attr) {
      if (attr.key === true) {
        const at: Attribute = { name: key, type: attr.type }
        ats.push(at)
      }
    }
  }
  return ats
}