package provider

import (
	"errors"
	"fmt"
	"net/http"
	"net/url"

	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
	"github.com/tidwall/gjson"
)

type ContextConfig struct {
	// @Title zh-CN 文件URL
	// @Description zh-CN 用于获取对话上下文的文件的URL。目前仅支持HTTP和HTTPS协议，纯文本格式文件
	fileUrl string `required:"true" yaml:"url" json:"url"`
	// @Title zh-CN 上游服务名称
	// @Description zh-CN 文件服务所对应的网关内上游服务名称
	serviceName string `required:"true" yaml:"serviceName" json:"serviceName"`
	// @Title zh-CN 上游服务端口
	// @Description zh-CN 文件服务所对应的网关内上游服务名称
	servicePort int64 `required:"true" yaml:"servicePort" json:"servicePort"`

	fileUrlObj *url.URL `yaml:"-"`
}

func (c *ContextConfig) FromJson(json gjson.Result) {
	c.fileUrl = json.Get("fileUrl").String()
	c.serviceName = json.Get("serviceName").String()
	c.servicePort = json.Get("servicePort").Int()
}

func (c *ContextConfig) Validate() error {
	if c.fileUrl == "" {
		return errors.New("missing fileUrl in context config")
	}
	if fileUrlObj, err := url.Parse(c.fileUrl); err != nil {
		return fmt.Errorf("invalid fileUrl in context config: %v", err)
	} else {
		c.fileUrlObj = fileUrlObj
	}
	if c.serviceName == "" {
		return errors.New("missing serviceName in context config")
	}
	if c.servicePort == 0 {
		return errors.New("missing servicePort in context config")
	}
	return nil
}

type contextCache struct {
	client  wrapper.HttpClient
	fileUrl *url.URL
	timeout uint32

	loaded  bool
	content string
}

func (c *contextCache) GetContent(callback func(string, error), log wrapper.Log) error {
	if callback == nil {
		return errors.New("callback is nil")
	}

	if c.loaded {
		log.Debugf("context file loaded from cache")
		callback(c.content, nil)
		return nil
	}

	log.Infof("loading context file from %s", c.fileUrl.String())
	return c.client.Get(c.fileUrl.Path, nil, func(statusCode int, responseHeaders http.Header, responseBody []byte) {
		if statusCode != http.StatusOK {
			callback("", fmt.Errorf("failed to load context file, status: %d", statusCode))
			return
		}
		c.content = string(responseBody)
		c.loaded = true
		log.Debugf("content: %s", c.content)
		callback(c.content, nil)
	}, c.timeout)
}

func createContextCache(providerConfig *ProviderConfig) *contextCache {
	contextConfig := providerConfig.context
	if contextConfig == nil {
		return nil
	}
	fileUrlObj, _ := url.Parse(contextConfig.fileUrl)
	cluster := plainCluster{
		serviceName: contextConfig.serviceName,
		servicePort: contextConfig.servicePort,
		hostName:    fileUrlObj.Host,
	}
	return &contextCache{
		client:  wrapper.NewClusterClient(cluster),
		fileUrl: fileUrlObj,
		timeout: providerConfig.timeout,
	}
}