package main

import (
  "bytes"
  "encoding/json"
  "fmt"
  "io"
  "net/http"
  "os"
  "strings"
  "time"
)

func required(name string) string { value := os.Getenv(name); if value == "" { panic("Set " + name) }; return value }
func getenv(name, fallback string) string { if value := os.Getenv(name); value != "" { return value }; return fallback }

func postJSON(url string, payload any, token string, correlationId string) ([]byte, error) {
  body, _ := json.Marshal(payload)
  req, _ := http.NewRequest("POST", url, bytes.NewReader(body))
  req.Header.Set("Content-Type", "application/json")
  if token != "" { req.Header.Set("Authorization", "Bearer "+token) }
  if correlationId != "" { req.Header.Set("X-Correlation-Id", correlationId) }
  return send(req)
}

func optional(name, fallback string) string {
    value := os.Getenv(name)
    if value == "" {
        return fallback
    }
    return value
}

func getJSON(url string, token string, correlationId string) ([]byte, error) {
  req, _ := http.NewRequest("GET", url, nil)
  req.Header.Set("Authorization", "Bearer "+token)
  req.Header.Set("X-Correlation-Id", correlationId)
  return send(req)
}

func send(req *http.Request) ([]byte, error) {
  client := &http.Client{Timeout: 45 * time.Second}
  resp, err := client.Do(req)
  if err != nil { return nil, err }
  defer resp.Body.Close()
  result, _ := io.ReadAll(resp.Body)
  if resp.StatusCode < 200 || resp.StatusCode >= 300 { return nil, fmt.Errorf("HTTP %d: %s", resp.StatusCode, string(result)) }
  return result, nil
}

func values(fit, demand, margin, cost, risk, customer float64) map[string]float64 {
  return map[string]float64{
    "assign_rental_vehicle_customer_fit_score": fit,
    "assign_rental_vehicle_vehicle_or_resource_fit": demand,
    "assign_rental_vehicle_operational_readiness": margin,
    "assign_rental_vehicle_financial_impact": cost,
    "assign_rental_vehicle_risk_exposure": risk,
    "assign_rental_vehicle_time_sensitivity": customer,
  }
}

func main() {
  identityURL := getenv("DECISIOQ_IDENTITY_URL", "https://identity.vinquery.com/connect/token")
  catalogURL := strings.TrimRight(getenv("DECISIOQ_DKS_URL", "https://dks.vinquery.com"), "/")
  decisionServiceURL := strings.TrimRight(getenv("DECISIOQ_DDE_URL", "https://dde.vinquery.com"), "/")
  correlationID := fmt.Sprintf("auto-rent-008-go-%d", time.Now().Unix())

  tokenBody, err := postJSON(identityURL, map[string]string{
    "clientId": required("DECISIOQ_CLIENT_ID"),
    "clientSecret": required("DECISIOQ_CLIENT_SECRET"),
        "audience": optional("DECISIOQ_AUDIENCE", "vinquery:api:decisioq"),
  }, "", "")
  if err != nil { panic(err) }
  var token struct{ JwtToken string `json:"jwtToken"` }
  json.Unmarshal(tokenBody, &token)

  if _, err = getJSON(catalogURL+"/decisioncatalog/decisions/AUTO-RENT-008", token.JwtToken, correlationID); err != nil { panic(err) }

  executionRequest := map[string]any{
    "decisionId": "AUTO-RENT-008",
    "profileId": "balanced",
    "scenarioId": "standard_rental",
    "algorithm": "TOPSIS",
    "weightStrategy": "Expert",
    "runSensitivity": false,
    "requestContext": map[string]string{"correlationId": correlationID},
    "options": []map[string]any{
      {"optionId": "OPTION-001", "name": "Compact SUV Unit", "values": values(88, 91, 84, 76, 20, 26)},
      {"optionId": "OPTION-002", "name": "Standard Sedan Unit", "values": values(79, 85, 92, 70, 18, 34)},
      {"optionId": "OPTION-003", "name": "Premium SUV Unit", "values": values(92, 73, 68, 88, 42, 50)},
    },
  }
  result, err := postJSON(decisionServiceURL+"/api/v1/decide", executionRequest, token.JwtToken, correlationID)
  if err != nil { panic(err) }
  os.Stdout.Write(result)
}