package rtsp

import (
	"bufio"
	"context"
	"encoding/base64"
	"fmt"
	"net"
	"strings"
	"time"

	"git.ilapage.cn/ila/yovision/Sense/server/app/sense/onvif"
)

type Credential struct{ Username, Password string }
type Result struct {
	Status    string `json:"status"`
	LatencyMS int64  `json:"latencyMs"`
	Detail    string `json:"detail"`
}
type Verifier interface {
	Verify(context.Context, string, Credential) (Result, error)
}
type NetVerifier struct {
	Timeout time.Duration
	Policy  onvif.Policy
}

func (v NetVerifier) Verify(ctx context.Context, raw string, credential Credential) (Result, error) {
	parsed, ip, err := v.Policy.ValidateURL(ctx, raw, "rtsp")
	if err != nil {
		return Result{}, err
	}
	port := parsed.Port()
	if port == "" {
		port = "554"
	}
	timeout := v.Timeout
	if timeout <= 0 {
		timeout = 5 * time.Second
	}
	started := time.Now()
	connection, err := (&net.Dialer{Timeout: timeout}).DialContext(ctx, "tcp", net.JoinHostPort(ip.String(), port))
	if err != nil {
		return Result{Status: "unreachable", Detail: "无法连接视频端口"}, nil
	}
	defer connection.Close()
	_ = connection.SetDeadline(time.Now().Add(timeout))
	authorization := ""
	if credential.Username != "" {
		authorization = "Authorization: Basic " + base64.StdEncoding.EncodeToString([]byte(credential.Username+":"+credential.Password)) + "\r\n"
	}
	request := fmt.Sprintf("OPTIONS %s RTSP/1.0\r\nCSeq: 1\r\nUser-Agent: YoVision-Sense\r\n%s\r\n", parsed.String(), authorization)
	if _, err = connection.Write([]byte(request)); err != nil {
		return Result{}, err
	}
	line, err := bufio.NewReader(connection).ReadString('\n')
	if err != nil {
		return Result{Status: "timeout", Detail: "等待视频响应超时"}, nil
	}
	result := Result{Status: "ready", Detail: "码流可访问", LatencyMS: time.Since(started).Milliseconds()}
	if strings.Contains(line, " 401 ") {
		result.Status = "authentication_failed"
		result.Detail = "设备拒绝了当前 RTSP 凭据"
	} else if !strings.Contains(line, " 200 ") {
		result.Status = "failed"
		result.Detail = "设备返回非成功状态"
	}
	return result, nil
}