package btwaf

import (
	"crypto/md5"
	"crypto/tls"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"time"

	"github.com/go-resty/resty/v2"
)

type Client struct {
	client *resty.Client
}

func NewClient(serverUrl, apiKey string) (*Client, error) {
	if serverUrl == "" {
		return nil, fmt.Errorf("sdkerr: unset serverUrl")
	}
	if _, err := url.Parse(serverUrl); err != nil {
		return nil, fmt.Errorf("sdkerr: invalid serverUrl: %w", err)
	}
	if apiKey == "" {
		return nil, fmt.Errorf("sdkerr: unset apiKey")
	}

	client := resty.New().
		SetBaseURL(strings.TrimRight(serverUrl, "/")+"/api").
		SetHeader("Accept", "application/json").
		SetHeader("Content-Type", "application/json").
		SetHeader("User-Agent", "certimate").
		SetPreRequestHook(func(c *resty.Client, req *http.Request) error {
			timestamp := fmt.Sprintf("%d", time.Now().Unix())
			keyMd5 := md5.Sum([]byte(apiKey))
			keyMd5Hex := strings.ToLower(hex.EncodeToString(keyMd5[:]))
			signMd5 := md5.Sum([]byte(timestamp + keyMd5Hex))
			signMd5Hex := strings.ToLower(hex.EncodeToString(signMd5[:]))
			req.Header.Set("waf_request_time", timestamp)
			req.Header.Set("waf_request_token", signMd5Hex)

			return nil
		})

	return &Client{client}, nil
}

func (c *Client) SetTimeout(timeout time.Duration) *Client {
	c.client.SetTimeout(timeout)
	return c
}

func (c *Client) SetTLSConfig(config *tls.Config) *Client {
	c.client.SetTLSClientConfig(config)
	return c
}

func (c *Client) newRequest(method string, path string) (*resty.Request, error) {
	if method == "" {
		return nil, fmt.Errorf("sdkerr: unset method")
	}
	if path == "" {
		return nil, fmt.Errorf("sdkerr: unset path")
	}

	req := c.client.R()
	req.Method = method
	req.URL = path
	return req, nil
}

func (c *Client) doRequest(req *resty.Request) (*resty.Response, error) {
	if req == nil {
		return nil, fmt.Errorf("sdkerr: nil request")
	}

	// WARN:
	//   PLEASE DO NOT USE `req.SetResult` or `req.SetError` HERE! USE `doRequestWithResult` INSTEAD.

	resp, err := req.Send()
	if err != nil {
		return resp, fmt.Errorf("sdkerr: failed to send request: %w", err)
	} else if resp.IsError() {
		return resp, fmt.Errorf("sdkerr: unexpected status code: %d, resp: %s", resp.StatusCode(), resp.String())
	}

	return resp, nil
}

func (c *Client) doRequestWithResult(req *resty.Request, res apiResponse) (*resty.Response, error) {
	if req == nil {
		return nil, fmt.Errorf("sdkerr: nil request")
	}

	resp, err := c.doRequest(req)
	if err != nil {
		if resp != nil {
			json.Unmarshal(resp.Body(), &res)
		}
		return resp, err
	}

	if len(resp.Body()) != 0 {
		if err := json.Unmarshal(resp.Body(), &res); err != nil {
			return resp, fmt.Errorf("sdkerr: failed to unmarshal response: %w", err)
		} else {
			if code := res.GetCode(); code != 0 {
				return resp, fmt.Errorf("sdkerr: api error: code='%d'", code)
			}
		}
	}

	return resp, nil
}