package cav2

import (
	"crypto/hmac"
	"crypto/sha1"
	"encoding/hex"
	"encoding/json"
	"errors"
	"fmt"
	"hospital-admin-api/config"
	"io"
	"net/http"
	"net/url"
	"sort"
	"strings"
	"time"
)

type Client struct {
	BaseURL    string
	AppID      string
	AppSecret  string
	HTTPClient *http.Client
}

func NewClient(baseURL, appID, appSecret string) *Client {
	return &Client{
		BaseURL:   strings.TrimRight(baseURL, "/"),
		AppID:     appID,
		AppSecret: appSecret,
		HTTPClient: &http.Client{
			Timeout: 15 * time.Second,
		},
	}
}

func NewClientFromConfig() *Client {
	baseURL := config.C.CaOnlineV2.CaOnlineAPIURL
	appID := config.C.CaOnlineV2.CaOnlineAppID
	appSecret := config.C.CaOnlineV2.CaOnlineAppSecret

	if baseURL == "" {
		baseURL = config.C.CaOnline.CaOnlineApiUrl
	}
	if appID == "" {
		appID = config.C.CaOnline.CaOnlineAppId
	}
	if appSecret == "" {
		appSecret = config.C.CaOnline.CaOnlineAppSecret
	}

	return NewClient(
		baseURL,
		appID,
		appSecret,
	)
}

func (c *Client) postForm(path string, form url.Values, out interface{}) error {
	if c == nil {
		return errors.New("ca v2 client is nil")
	}
	if c.BaseURL == "" || c.AppID == "" || c.AppSecret == "" {
		return errors.New("ca v2 client config is incomplete")
	}
	if c.HTTPClient == nil {
		c.HTTPClient = &http.Client{Timeout: 15 * time.Second}
	}

	payload := strings.NewReader(form.Encode())
	req, err := http.NewRequest(http.MethodPost, c.BaseURL+path, payload)
	if err != nil {
		return err
	}

	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	req.Header.Set("app_id", c.AppID)
	req.Header.Set("signature", c.signature(form))

	resp, err := c.HTTPClient.Do(req)
	if err != nil {
		return err
	}
	defer func() {
		_ = resp.Body.Close()
	}()

	if resp.StatusCode != http.StatusOK {
		return fmt.Errorf("ca v2 request failed: http %d", resp.StatusCode)
	}

	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}

	var envelope responseEnvelope
	if err := json.Unmarshal(respBody, &envelope); err != nil {
		return err
	}

	if envelope.ResultCode != 0 {
		if envelope.ResultMsg != "" {
			return errors.New(envelope.ResultMsg)
		}
		return fmt.Errorf("ca v2 request failed with code %d", envelope.ResultCode)
	}

	if out == nil {
		return nil
	}

	body := strings.TrimSpace(string(envelope.Body))
	if body == "" || body == "null" {
		return nil
	}

	return json.Unmarshal(envelope.Body, out)
}

func (c *Client) postFormForString(path string, form url.Values) (string, error) {
	var raw json.RawMessage
	if err := c.postForm(path, form, &raw); err != nil {
		return "", err
	}
	body := strings.TrimSpace(string(raw))
	if body == "" || body == "null" {
		return "", nil
	}

	var text string
	if err := json.Unmarshal(raw, &text); err == nil {
		return text, nil
	}

	var data map[string]string
	if err := json.Unmarshal(raw, &data); err != nil {
		return "", err
	}

	for _, key := range []string{"url", "authUrl", "faceUrl", "h5Url"} {
		if value := strings.TrimSpace(data[key]); value != "" {
			return value, nil
		}
	}

	return "", errors.New("ca v2 string body not found")
}

func (c *Client) signature(form url.Values) string {
	keys := make([]string, 0, len(form))
	for key := range form {
		keys = append(keys, key)
	}
	sort.Strings(keys)

	values := make([]string, 0, len(keys))
	for _, key := range keys {
		for _, value := range form[key] {
			values = append(values, value)
		}
	}

	h := hmac.New(sha1.New, []byte(c.AppSecret))
	h.Write([]byte(strings.Join(values, "&")))
	return hex.EncodeToString(h.Sum(nil))
}

func setValue(form url.Values, key, value string) {
	if strings.TrimSpace(value) == "" {
		return
	}
	form.Set(key, value)
}