package upstreamimpl

import (
	"context"
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"strings"
	"time"

	sharedtoken "git.5iot.com/iotlcm-public/iotlcm-upstream-chan/internal/token"
)

type QianxunTokenConfig struct {
	BaseURL    string
	Path       string
	OperatorID string
	AppID      string
	TokenType  string
	Key        string
	Timeout    time.Duration
}

type QianxunTokenProvider struct {
	baseURL, path, operatorID, appID, tokenType, key string
	client                                           *http.Client
}

type qianxunTokenResponse struct {
	Code int    `json:"code"`
	Msg  string `json:"msg"`
	Data struct {
		Token      string `json:"token"`
		ExpireDate int64  `json:"expireDate"`
	} `json:"data"`
}

func NewQianxunTokenProvider(config QianxunTokenConfig) *QianxunTokenProvider {
	timeout := config.Timeout
	if timeout <= 0 {
		timeout = defaultUpstreamHTTPTimeout
	}
	return &QianxunTokenProvider{
		baseURL: strings.TrimRight(strings.TrimSpace(config.BaseURL), "/"),
		path:    normalizeProviderPath(config.Path, "/"), operatorID: strings.TrimSpace(config.OperatorID),
		appID: strings.TrimSpace(config.AppID), tokenType: strings.TrimSpace(config.TokenType), key: config.Key,
		client: &http.Client{Timeout: timeout},
	}
}

func qianxunSharedSign(operatorID, appID, key string) string {
	sum := md5.Sum([]byte(operatorID + appID + key))
	return hex.EncodeToString(sum[:])
}

func (p *QianxunTokenProvider) Fetch(ctx context.Context) (sharedtoken.OneLinkToken, error) {
	if p == nil || p.client == nil {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("qianxun token provider is not initialized")
	}
	if p.baseURL == "" || p.operatorID == "" || p.appID == "" || p.tokenType == "" || p.key == "" {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("qianxun token endpoint and credentials are required")
	}
	payload := map[string]string{"operatorId": p.operatorID, "appId": p.appID, "tokenType": p.tokenType, "sign": qianxunSharedSign(p.operatorID, p.appID, p.key)}
	body, err := json.Marshal(payload)
	if err != nil {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("encode qianxun token request: %w", err)
	}
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, joinProviderURL(p.baseURL, p.path), strings.NewReader(string(body)))
	if err != nil {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("create qianxun token request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Accept", "application/json")
	resp, err := p.client.Do(req)
	if err != nil {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("request qianxun token: %w", err)
	}
	defer resp.Body.Close()
	responseBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("read qianxun token response: %w", err)
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("qianxun token HTTP status %d", resp.StatusCode)
	}
	var output qianxunTokenResponse
	if err := json.Unmarshal(responseBody, &output); err != nil {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("decode qianxun token response: %w", err)
	}
	if output.Code != 0 {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("qianxun token failed: code=%d msg=%s", output.Code, output.Msg)
	}
	value := strings.TrimSpace(output.Data.Token)
	if value == "" {
		return sharedtoken.OneLinkToken{}, fmt.Errorf("qianxun token is empty")
	}
	now := time.Now()
	var expiresAt time.Time
	if output.Data.ExpireDate > 0 {
		expiresAt = now.Add(time.Duration(output.Data.ExpireDate) * time.Second)
	}
	return sharedtoken.OneLinkToken{Value: value, CreatedAt: now, ExpiresAt: expiresAt}, nil
}

func (p *QianxunTokenProvider) FetchToken(ctx context.Context, _ string) (sharedtoken.OneLinkToken, error) {
	return p.Fetch(ctx)
}

type qianxunFetcher struct{ provider *QianxunTokenProvider }

func (f qianxunFetcher) FetchToken(ctx context.Context, _ string) (sharedtoken.OneLinkToken, error) {
	return f.provider.Fetch(ctx)
}