package main

import (
	"crypto/x509"
	"encoding/json"
	"encoding/pem"
	"fmt"
	"io"
	"net/http"
	"os"
	"path/filepath"
	"strings"
	"time"

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

// Check if the default certificates is correctly setup
func handleDefaultCertCheck(w http.ResponseWriter, r *http.Request) {
	type CheckResult struct {
		DefaultPubExists bool
		DefaultPriExists bool
	}

	pub, pri := tlsCertManager.DefaultCertExistsSep()
	js, _ := json.Marshal(CheckResult{
		pub,
		pri,
	})

	utils.SendJSONResponse(w, string(js))
}

// Return a list of domains where the certificates covers
func handleListCertificate(w http.ResponseWriter, r *http.Request) {
	filenames, err := tlsCertManager.ListCertDomains()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	showDate, _ := utils.GetPara(r, "date")
	if showDate == "true" {
		type CertInfo struct {
			Domain           string
			LastModifiedDate string
			ExpireDate       string
			RemainingDays    int
			UseDNS           bool
		}

		results := []*CertInfo{}

		for _, filename := range filenames {
			certFilepath := filepath.Join(tlsCertManager.CertStore, filename+".pem")
			//keyFilepath := filepath.Join(tlsCertManager.CertStore, filename+".key")
			fileInfo, err := os.Stat(certFilepath)
			if err != nil {
				utils.SendErrorResponse(w, "invalid domain certificate discovered: "+filename)
				return
			}
			modifiedTime := fileInfo.ModTime().Format("2006-01-02 15:04:05")

			certExpireTime := "Unknown"
			certBtyes, err := os.ReadFile(certFilepath)
			expiredIn := 0
			if err != nil {
				//Unable to load this file
				continue
			} else {
				//Cert loaded. Check its expire time
				block, _ := pem.Decode(certBtyes)
				if block != nil {
					cert, err := x509.ParseCertificate(block.Bytes)
					if err == nil {
						certExpireTime = cert.NotAfter.Format("2006-01-02 15:04:05")

						duration := cert.NotAfter.Sub(time.Now())

						// Convert the duration to days
						expiredIn = int(duration.Hours() / 24)
					}
				}
			}
			certInfoFilename := filepath.Join(tlsCertManager.CertStore, filename+".json")
			useDNSValidation := false                                //Default to false for HTTP TLS certificates
			certInfo, err := acme.LoadCertInfoJSON(certInfoFilename) //Note: Not all certs have info json
			if err == nil {
				useDNSValidation = certInfo.UseDNS
			}

			thisCertInfo := CertInfo{
				Domain:           filename,
				LastModifiedDate: modifiedTime,
				ExpireDate:       certExpireTime,
				RemainingDays:    expiredIn,
				UseDNS:           useDNSValidation,
			}

			results = append(results, &thisCertInfo)
		}

		js, _ := json.Marshal(results)
		w.Header().Set("Content-Type", "application/json")
		w.Write(js)
	} else {
		response, err := json.Marshal(filenames)
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		w.Header().Set("Content-Type", "application/json")
		w.Write(response)
	}

}

// List all certificates and map all their domains to the cert filename
func handleListDomains(w http.ResponseWriter, r *http.Request) {
	filenames, err := os.ReadDir("./conf/certs/")

	if err != nil {
		utils.SendErrorResponse(w, err.Error())
		return
	}

	certnameToDomainMap := map[string]string{}
	for _, filename := range filenames {
		if filename.IsDir() {
			continue
		}
		certFilepath := filepath.Join("./conf/certs/", filename.Name())

		certBtyes, err := os.ReadFile(certFilepath)
		if err != nil {
			// Unable to load this file
			SystemWideLogger.PrintAndLog("TLS", "Unable to load certificate: "+certFilepath, err)
			continue
		} else {
			// Cert loaded. Check its expiry time
			block, _ := pem.Decode(certBtyes)
			if block != nil {
				cert, err := x509.ParseCertificate(block.Bytes)
				if err == nil {
					certname := strings.TrimSuffix(filepath.Base(certFilepath), filepath.Ext(certFilepath))
					for _, dnsName := range cert.DNSNames {
						certnameToDomainMap[dnsName] = certname
					}
					certnameToDomainMap[cert.Subject.CommonName] = certname
				}
			}
		}
	}

	requireCompact, _ := utils.GetPara(r, "compact")
	if requireCompact == "true" {
		result := make(map[string][]string)

		for key, value := range certnameToDomainMap {
			if _, ok := result[value]; !ok {
				result[value] = make([]string, 0)
			}

			result[value] = append(result[value], key)
		}

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

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

// Handle front-end toggling TLS mode
func handleToggleTLSProxy(w http.ResponseWriter, r *http.Request) {
	currentTlsSetting := true //Default to true
	if dynamicProxyRouter.Option != nil {
		currentTlsSetting = dynamicProxyRouter.Option.UseTls
	}
	if sysdb.KeyExists("settings", "usetls") {
		sysdb.Read("settings", "usetls", &currentTlsSetting)
	}

	if r.Method == http.MethodGet {
		//Get the current status
		js, _ := json.Marshal(currentTlsSetting)
		utils.SendJSONResponse(w, string(js))
	} else if r.Method == http.MethodPost {
		newState, err := utils.PostBool(r, "set")
		if err != nil {
			utils.SendErrorResponse(w, "new state not set or invalid")
			return
		}
		if newState {
			sysdb.Write("settings", "usetls", true)
			SystemWideLogger.Println("Enabling TLS mode on reverse proxy")
			dynamicProxyRouter.UpdateTLSSetting(true)
		} else {
			sysdb.Write("settings", "usetls", false)
			SystemWideLogger.Println("Disabling TLS mode on reverse proxy")
			dynamicProxyRouter.UpdateTLSSetting(false)
		}
		utils.SendOK(w)
	} else {
		http.Error(w, "405 - Method not allowed", http.StatusMethodNotAllowed)
	}
}

// Handle the GET and SET of reverse proxy TLS versions
func handleSetTlsRequireLatest(w http.ResponseWriter, r *http.Request) {
	newState, err := utils.PostPara(r, "set")
	if err != nil {
		//GET
		var reqLatestTLS bool = false
		if sysdb.KeyExists("settings", "forceLatestTLS") {
			sysdb.Read("settings", "forceLatestTLS", &reqLatestTLS)
		}

		js, _ := json.Marshal(reqLatestTLS)
		utils.SendJSONResponse(w, string(js))
	} else {
		if newState == "true" {
			sysdb.Write("settings", "forceLatestTLS", true)
			SystemWideLogger.Println("Updating minimum TLS version to v1.2 or above")
			dynamicProxyRouter.UpdateTLSVersion(true)
		} else if newState == "false" {
			sysdb.Write("settings", "forceLatestTLS", false)
			SystemWideLogger.Println("Updating minimum TLS version to v1.0 or above")
			dynamicProxyRouter.UpdateTLSVersion(false)
		} else {
			utils.SendErrorResponse(w, "invalid state given")
		}
	}
}

// Handle download of the selected certificate
func handleCertDownload(w http.ResponseWriter, r *http.Request) {
	// get the certificate name
	certname, err := utils.GetPara(r, "certname")
	if err != nil {
		utils.SendErrorResponse(w, "invalid certname given")
		return
	}
	certname = filepath.Base(certname) //prevent path escape

	// check if the cert exists
	pubKey := filepath.Join(filepath.Join("./conf/certs"), certname+".key")
	priKey := filepath.Join(filepath.Join("./conf/certs"), certname+".pem")

	if utils.FileExists(pubKey) && utils.FileExists(priKey) {
		//Zip them and serve them via http download
		seeking, _ := utils.GetBool(r, "seek")
		if seeking {
			//This request only check if the key exists. Do not provide download
			utils.SendOK(w)
			return
		}

		//Serve both file in zip
		zipTmpFolder := "./tmp/download"
		os.MkdirAll(zipTmpFolder, 0775)
		zipFileName := filepath.Join(zipTmpFolder, certname+".zip")
		err := utils.ZipFiles(zipFileName, pubKey, priKey)
		if err != nil {
			http.Error(w, "Failed to create zip file", http.StatusInternalServerError)
			return
		}
		defer os.Remove(zipFileName) // Clean up the zip file after serving

		// Serve the zip file
		w.Header().Set("Content-Disposition", "attachment; filename=\""+certname+"_export.zip\"")
		w.Header().Set("Content-Type", "application/zip")
		http.ServeFile(w, r, zipFileName)
	} else {
		//Not both key exists
		utils.SendErrorResponse(w, "invalid key-pairs: private key or public key not found in key store")
		return
	}
}

// Handle upload of the certificate
func handleCertUpload(w http.ResponseWriter, r *http.Request) {
	// check if request method is POST
	if r.Method != "POST" {
		http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
		return
	}

	// get the key type
	keytype, err := utils.GetPara(r, "ktype")
	overWriteFilename := ""
	if err != nil {
		http.Error(w, "Not defined key type (pub / pri)", http.StatusBadRequest)
		return
	}

	// get the domain
	domain, err := utils.GetPara(r, "domain")
	if err != nil {
		//Assume localhost
		domain = "default"
	}

	if keytype == "pub" {
		overWriteFilename = domain + ".pem"
	} else if keytype == "pri" {
		overWriteFilename = domain + ".key"
	} else {
		http.Error(w, "Not supported keytype: "+keytype, http.StatusBadRequest)
		return
	}

	// parse multipart form data
	err = r.ParseMultipartForm(10 << 20) // 10 MB
	if err != nil {
		http.Error(w, "Failed to parse form data", http.StatusBadRequest)
		return
	}

	// get file from form data
	file, _, err := r.FormFile("file")
	if err != nil {
		http.Error(w, "Failed to get file", http.StatusBadRequest)
		return
	}
	defer file.Close()

	// create file in upload directory
	os.MkdirAll("./conf/certs", 0775)
	f, err := os.Create(filepath.Join("./conf/certs", overWriteFilename))
	if err != nil {
		http.Error(w, "Failed to create file", http.StatusInternalServerError)
		return
	}
	defer f.Close()

	// copy file contents to destination file
	_, err = io.Copy(f, file)
	if err != nil {
		http.Error(w, "Failed to save file", http.StatusInternalServerError)
		return
	}

	//Update cert list
	tlsCertManager.UpdateLoadedCertList()

	// send response
	fmt.Fprintln(w, "File upload successful!")
}

// Handle cert remove
func handleCertRemove(w http.ResponseWriter, r *http.Request) {
	domain, err := utils.PostPara(r, "domain")
	if err != nil {
		utils.SendErrorResponse(w, "invalid domain given")
		return
	}
	err = tlsCertManager.RemoveCert(domain)
	if err != nil {
		utils.SendErrorResponse(w, err.Error())
	}
}