package yunda

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"
)

type Config struct {
	BaseURL   string
	AppKey    string
	AppSecret string
	Timeout   time.Duration
}
type Client struct {
	baseURL    string
	appKey     string
	appSecret  string
	httpClient *http.Client
}
type Response struct {
	Status  json.RawMessage `json:"status"`
	Message string          `json:"message"`
	Result  json.RawMessage `json:"result"`
}

func NewClient(cfg Config) *Client {
	timeout := cfg.Timeout
	if timeout <= 0 {
		timeout = 10 * time.Second
	}
	return &Client{baseURL: strings.TrimRight(strings.TrimSpace(cfg.BaseURL), "/"), appKey: strings.TrimSpace(cfg.AppKey), appSecret: cfg.AppSecret, httpClient: &http.Client{Timeout: timeout}}
}

func (c *Client) Post(ctx context.Context, path string, params map[string]string, out any) (Response, error) {
	if c.baseURL == "" {
		return Response{}, errors.New("yunda base URL is required")
	}
	if c.appKey == "" || c.appSecret == "" {
		return Response{}, errors.New("yunda appKey and appSecret are required")
	}
	signed := make(map[string]string, len(params)+3)
	for key, value := range params {
		if strings.TrimSpace(value) != "" {
			signed[key] = value
		}
	}
	signed["appKey"] = c.appKey
	signed["timestamp"] = strconv.FormatInt(time.Now().Unix(), 10)
	signed["sign"] = BuildSign(c.appKey, c.appSecret, signed)
	form := url.Values{}
	for key, value := range signed {
		form.Set(key, value)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, c.baseURL+"/"+strings.TrimLeft(path, "/"), strings.NewReader(form.Encode()))
	if err != nil {
		return Response{}, err
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	resp, err := c.httpClient.Do(req)
	if err != nil {
		return Response{}, err
	}
	defer resp.Body.Close()
	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return Response{}, err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return Response{}, fmt.Errorf("yunda HTTP status %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
	}
	var response Response
	if err = json.Unmarshal(body, &response); err != nil {
		return Response{}, fmt.Errorf("decode yunda response: %w", err)
	}
	if status := response.StatusString(); status != "0" && status != "" {
		return response, fmt.Errorf("yunda business status %s: %s", status, response.Message)
	}
	if out != nil && len(response.Result) > 0 && string(response.Result) != "null" {
		if err = json.Unmarshal(response.Result, out); err != nil {
			return response, fmt.Errorf("decode yunda result: %w", err)
		}
	}
	return response, nil
}

func (r Response) StatusString() string {
	var value string
	if json.Unmarshal(r.Status, &value) == nil {
		return value
	}
	var number json.Number
	if json.Unmarshal(r.Status, &number) == nil {
		return number.String()
	}
	return ""
}