package facepp

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

const (
	DefaultEndpoint = "https://api-cn.faceplusplus.com/facepp/v1/skinanalyze_pro"
	defaultTimeout  = 60 * time.Second

	MapRedArea              = "red_area"
	MapBrownArea            = "brown_area"
	MapTextureEnhancedPores = "texture_enhanced_pores"
	MapTextureEnhancedLines = "texture_enhanced_lines"

	DefaultReturnMaps  = "red_area,brown_area,texture_enhanced_pores,texture_enhanced_lines"
	DefaultReturnMarks = "wrinkle_mark,right_nasolabial_list,right_mouth_list,right_eye_wrinkle_list,right_crowsfeet_list,right_cheek_list,left_nasolabial_list,left_mouth_list,left_eye_wrinkle_list,left_crowsfeet_list,left_cheek_list,glabella_wrinkle_list,forehead_wrinkle_list,dark_circle_outline,sensitivity_mark,melanin_mark,cheekbone_mark,blackheads_mark,pores_mark"
)

type Client struct {
	apiKey     string
	apiSecret  string
	endpoint   string
	httpClient *http.Client
}

func NewClient(apiKey, apiSecret string) *Client {
	return &Client{
		apiKey:    apiKey,
		apiSecret: apiSecret,
		endpoint:  DefaultEndpoint,
		httpClient: &http.Client{
			Timeout: defaultTimeout,
		},
	}
}

func (c *Client) WithEndpoint(endpoint string) *Client {
	if endpoint != "" {
		c.endpoint = endpoint
	}
	return c
}

func (c *Client) WithHTTPClient(httpClient *http.Client) *Client {
	if httpClient != nil {
		c.httpClient = httpClient
	}
	return c
}

func (c *Client) postForm(values url.Values) ([]byte, error) {
	if c.apiKey == "" || c.apiSecret == "" {
		return nil, errors.New("facepp: api_key or api_secret is empty")
	}

	values.Set("api_key", c.apiKey)
	values.Set("api_secret", c.apiSecret)

	req, err := http.NewRequest(http.MethodPost, c.endpoint, strings.NewReader(values.Encode()))
	if err != nil {
		return nil, err
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")

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

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

	if err := checkAPIError(body); err != nil {
		return body, err
	}

	if resp.StatusCode != http.StatusOK {
		return body, fmt.Errorf("facepp: http %d: %s", resp.StatusCode, strings.TrimSpace(string(body)))
	}

	return body, nil
}

func checkAPIError(body []byte) error {
	var apiErr APIError
	if err := json.Unmarshal(body, &apiErr); err != nil {
		return nil
	}
	if apiErr.ErrorMessage == "" {
		return nil
	}
	return &apiErr
}