package acme

import (
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"net/http"
	"net/mail"
	"os"
	"path/filepath"
	"time"

	"imuslab.com/zoraxy/mod/utils"
)

/*
	autorenew.go

	This script handle auto renew
*/

type AutoRenewConfig struct {
	Enabled      bool     //Automatic renew is enabled
	Email        string   //Email for acme
	RenewAll     bool     //Renew all or selective renew with the slice below
	FilesToRenew []string //If RenewAll is false, renew these certificate files
}

type AutoRenewer struct {
	ConfigFilePath string
	CertFolder     string
	RenewerConfig  *AutoRenewConfig
	TickerstopChan chan bool
}

// Create an auto renew agent, require config filepath and auto scan & renew interval (seconds)
// Set renew check interval to 0 for auto (1 day)
func NewAutoRenewer(config string, certFolder string, renewCheckInterval int64) (*AutoRenewer, error) {
	if renewCheckInterval == 0 {
		renewCheckInterval = 86400 //1 day
	}

	ticker := time.NewTicker(time.Duration(renewCheckInterval) * time.Second)
	done := make(chan bool)

	//Load the config file. If not found, create one
	if !utils.FileExists(config) {
		//Create one
		os.MkdirAll(filepath.Dir(config), 0775)
		newConfig := AutoRenewConfig{
			RenewAll:     true,
			FilesToRenew: []string{},
		}
		js, _ := json.MarshalIndent(newConfig, "", " ")
		err := os.WriteFile(config, js, 0775)
		if err != nil {
			return nil, errors.New("Failed to create acme auto renewer config: " + err.Error())
		}
	}

	renewerConfig := AutoRenewConfig{}
	content, err := os.ReadFile(config)
	if err != nil {
		return nil, errors.New("Failed to open acme auto renewer config: " + err.Error())
	}

	err = json.Unmarshal(content, &renewerConfig)
	if err != nil {
		return nil, errors.New("Malformed acme config file: " + err.Error())
	}

	//Create an Auto renew object
	thisRenewer := AutoRenewer{
		ConfigFilePath: config,
		CertFolder:     certFolder,
		RenewerConfig:  &renewerConfig,
		TickerstopChan: done,
	}

	//Check and renew certificate on startup
	thisRenewer.CheckAndRenewCertificates()

	//Start the ticker to check and renew every x seconds
	go func() {
		for {
			select {
			case <-done:
				return
			case <-ticker.C:
				log.Println("Check and renew certificates in progress")
				thisRenewer.CheckAndRenewCertificates()
			}
		}
	}()

	return &thisRenewer, nil
}

// Handle update auto renew domains
// Set opr for different mode of operations
// opr = setSelected -> Enter a list of file names (or matching rules) for auto renew
// opr = setAuto -> Set to use auto detect certificates and renew
func (a *AutoRenewer) HandleSetAutoRenewDomains(w http.ResponseWriter, r *http.Request) {
	opr, err := utils.GetPara(r, "opr")
	if err != nil {
		utils.SendErrorResponse(w, "Operation not set")
		return
	}

	if opr == "setSelected" {
		files, err := utils.PostPara(r, "domains")
		if err != nil {
			utils.SendErrorResponse(w, "Domains is not defined")
			return
		}

		//Parse it int array of string
		matchingRuleFiles := []string{}
		err = json.Unmarshal([]byte(files), &matchingRuleFiles)
		if err != nil {
			utils.SendErrorResponse(w, err.Error())
			return
		}

		//Update the configs
		a.RenewerConfig.RenewAll = false
		a.RenewerConfig.FilesToRenew = matchingRuleFiles
		a.saveRenewConfigToFile()
		utils.SendOK(w)
	} else if opr == "setAuto" {
		a.RenewerConfig.RenewAll = true
		a.saveRenewConfigToFile()
		utils.SendOK(w)
	}

}

// if auto renew all is true (aka auto scan), it will return []string{"*"}
func (a *AutoRenewer) HandleLoadAutoRenewDomains(w http.ResponseWriter, r *http.Request) {
	results := []string{}
	if a.RenewerConfig.RenewAll {
		//Auto pick which cert to renew.
		results = append(results, "*")
	} else {
		//Manually set the files to renew
		results = a.RenewerConfig.FilesToRenew
	}

	js, _ := json.Marshal(results)
	utils.SendJSONResponse(w, string(js))
}

func (a *AutoRenewer) HandleRenewNow(w http.ResponseWriter, r *http.Request) {

}

func (a *AutoRenewer) HandleAutoRenewEnable(w http.ResponseWriter, r *http.Request) {
	val, err := utils.PostPara(r, "enable")
	if err != nil {
		js, _ := json.Marshal(a.RenewerConfig.Enabled)
		utils.SendJSONResponse(w, string(js))
	} else {
		if val == "true" {
			//Check if the email is not empty
			if a.RenewerConfig.Email == "" {
				utils.SendErrorResponse(w, "Email is not set")
				return
			}

			a.RenewerConfig.Enabled = true
			a.saveRenewConfigToFile()
			log.Println("[AutoRenew] ACME auto renew enabled")
		} else {
			a.RenewerConfig.Enabled = false
			a.saveRenewConfigToFile()
			log.Println("[AutoRenew] ACME auto renew disabled")
		}
	}
}

func (a *AutoRenewer) HandleACMEEmail(w http.ResponseWriter, r *http.Request) {

	email, err := utils.PostPara(r, "set")
	if err != nil {
		//Return the current email to user
		js, _ := json.Marshal(a.RenewerConfig.Email)
		utils.SendJSONResponse(w, string(js))
	} else {
		//Check if the email is valid
		_, err := mail.ParseAddress(email)
		if err != nil {
			utils.SendErrorResponse(w, err.Error())
			return
		}

		//Set the new config
		a.RenewerConfig.Email = email
		a.saveRenewConfigToFile()
	}

}

// Check and renew certificates. This check all the certificates in the
// certificate folder and return a list of certs that is renewed in this call
// Return string array with length 0 when no cert is expired
func (a *AutoRenewer) CheckAndRenewCertificates() ([]string, error) {
	certFolder := a.CertFolder
	files, err := os.ReadDir(certFolder)
	if err != nil {
		log.Println("Unable to renew certificates: " + err.Error())
		return []string{}, err
	}

	fmt.Println("[ACME DEBUG] Cert found: ", files)
	return []string{}, nil
}

// Write the current renewer config to file
func (a *AutoRenewer) saveRenewConfigToFile() error {
	js, _ := json.MarshalIndent(a.RenewerConfig, "", " ")
	return os.WriteFile(a.ConfigFilePath, js, 0775)
}