package photo

import (
	"bytes"
	"fmt"
	"io"
	"net/http"
	"path/filepath"
	"strconv"
	"time"

	"code.nonshy.com/nonshy/website/pkg/chat"
	"code.nonshy.com/nonshy/website/pkg/config"
	"code.nonshy.com/nonshy/website/pkg/encryption/coldstorage"
	"code.nonshy.com/nonshy/website/pkg/geoip"
	"code.nonshy.com/nonshy/website/pkg/log"
	"code.nonshy.com/nonshy/website/pkg/mail"
	"code.nonshy.com/nonshy/website/pkg/models"
	"code.nonshy.com/nonshy/website/pkg/photo"
	"code.nonshy.com/nonshy/website/pkg/session"
	"code.nonshy.com/nonshy/website/pkg/templates"
	"code.nonshy.com/nonshy/website/pkg/utility"
)

// CertificationRequiredError handles the error page when a user is denied due to lack of certification.
func CertificationRequiredError() http.HandlerFunc {
	tmpl := templates.Must("errors/certification_required.html")
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		currentUser, err := session.CurrentUser(r)
		if err != nil {
			session.FlashError(w, r, "Unexpected error: could not get currentUser.")
			templates.Redirect(w, "/")
			return
		}

		// Get the current user's cert photo (or create the DB record).
		cert, err := models.GetCertificationPhoto(currentUser.ID)
		if err != nil {
			session.FlashError(w, r, "Unexpected error: could not get or create CertificationPhoto record.")
			templates.Redirect(w, "/")
			return
		}

		var vars = map[string]interface{}{
			"CertificationPhoto": cert,
		}
		if err := tmpl.Execute(w, r, vars); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	})
}

// Certification photo controller.
func Certification() http.HandlerFunc {
	tmpl := templates.Must("photo/certification.html")
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		currentUser, err := session.CurrentUser(r)
		if err != nil {
			session.FlashError(w, r, "Unexpected error: could not get currentUser.")
			templates.Redirect(w, "/")
			return
		}

		// Get the current user's cert photo (or create the DB record).
		cert, err := models.GetCertificationPhoto(currentUser.ID)
		if err != nil {
			session.FlashError(w, r, "Unexpected error: could not get or create CertificationPhoto record.")
			templates.Redirect(w, "/")
			return
		}

		// Uploading?
		if r.Method == http.MethodPost {
			// Are they deleting their photo?
			if r.PostFormValue("delete") == "true" {

				// Primary cert photo
				if cert.Filename != "" {
					if err := photo.Delete(cert.Filename); err != nil {
						log.Error("Failed to delete old cert photo for %s (%s): %s", currentUser.Username, cert.Filename, err)
					}
					cert.Filename = ""
				}

				// Secondary cert photo
				if cert.SecondaryFilename != "" {
					if err := photo.Delete(cert.SecondaryFilename); err != nil {
						log.Error("Failed to delete old cert photo for %s (%s): %s", currentUser.Username, cert.SecondaryFilename, err)
					}
					cert.SecondaryFilename = ""
				}

				cert.Status = models.CertificationPhotoNeeded
				cert.AdminComment = ""
				cert.SecondaryVerified = false
				cert.Save()

				// Removing your photo = not certified again.
				currentUser.Certified = false
				if err := currentUser.Save(); err != nil {
					session.FlashError(w, r, "Error saving your User data: %s", err)
				}

				// Log the change.
				models.LogDeleted(currentUser, nil, "certification_photos", currentUser.ID, "Removed their certification photo.", cert)

				// Kick them from the chat room if they are online.
				if _, err := chat.MaybeDisconnectUser(currentUser); err != nil {
					log.Error("chat.MaybeDisconnectUser(%s#%d): %s", currentUser.Username, currentUser.ID, err)
				}

				session.Flash(w, r, "Your certification photo has been deleted.")
				templates.Redirect(w, r.URL.Path)
				return
			}

			// Is it their secondary form of ID being uploaded?
			isSecondary := r.PostFormValue("secondary") == "true"

			// Get the uploaded file.
			file, header, err := r.FormFile("file")
			if err != nil {
				session.FlashError(w, r, "Error receiving your file: %s", err)
				templates.Redirect(w, r.URL.Path)
				return
			}

			var buf bytes.Buffer
			io.Copy(&buf, file)

			filename, _, err := photo.UploadPhoto(photo.UploadConfig{
				User:      currentUser,
				Extension: filepath.Ext(header.Filename),
				Data:      buf.Bytes(),
			})
			if err != nil {
				session.FlashError(w, r, "Error processing your upload: %s", err)
				templates.Redirect(w, r.URL.Path)
				return
			}

			// Are they replacing their old photo?
			if cert.Filename != "" && !isSecondary {
				if err := photo.Delete(cert.Filename); err != nil {
					log.Error("Failed to delete old cert photo for %s (%s): %s", currentUser.Username, cert.Filename, err)
				}
			} else if isSecondary && cert.SecondaryFilename != "" {
				if err := photo.Delete(cert.SecondaryFilename); err != nil {
					log.Error("Failed to delete old cert photo for %s (%s): %s", currentUser.Username, cert.SecondaryFilename, err)
				}
			}

			// Update their certification photo.
			cert.Status = models.CertificationPhotoPending
			if isSecondary {
				cert.SecondaryFilename = filename
				cert.SecondaryNeeded = true
				cert.SecondaryVerified = false
			} else {
				cert.Filename = filename
			}
			cert.AdminComment = ""
			cert.IPAddress = utility.IPAddress(r)

			// Secondary ID workflow: if the user
			// 1. Uploads a regular cert photo
			// 2. An admin marks secondary ID as needed
			// 3. They remove everything and reupload a new cert photo, without a secondary ID attached
			// Then we don't e-mail the admin for approval yet, and move straight to Secondary ID Requested
			// for the user to upload their secondary ID now.
			if cert.Status == models.CertificationPhotoPending && cert.SecondaryNeeded && cert.SecondaryFilename == "" {
				cert.Status = models.CertificationPhotoSecondary
			}

			if err := cert.Save(); err != nil {
				session.FlashError(w, r, "Error saving your CertificationPhoto: %s", err)
				templates.Redirect(w, r.URL.Path)
				return
			}

			// Set their approval status back to false.
			currentUser.Certified = false
			if err := currentUser.Save(); err != nil {
				session.FlashError(w, r, "Error saving your User data: %s", err)
			}

			// Kick them from the chat room if they are online.
			if _, err := chat.MaybeDisconnectUser(currentUser); err != nil {
				log.Error("chat.MaybeDisconnectUser(%s#%d): %s", currentUser.Username, currentUser.ID, err)
			}

			// Log the change. Note the original IP and GeoIP insights - we once saw a spammer upload
			// their cert photo from Nigeria, and before we could reject it, they removed and reuploaded
			// it from New York using a VPN. If it wasn't seen in real time, this might have slipped by.
			var insights string
			if i, err := geoip.GetRequestInsights(r); err == nil {
				insights = i.String()
			} else {
				insights = "error: " + err.Error()
			}
			models.LogCreated(
				currentUser,
				"certification_photos",
				currentUser.ID,
				fmt.Sprintf(
					"Uploaded a new certification photo.\n\n* From IP address: %s\n* GeoIP insight: %s",
					cert.IPAddress,
					insights,
				),
			)

			session.Flash(w, r, "Your certification photo has been uploaded and is now awaiting approval.")
			templates.Redirect(w, r.URL.Path)
			return
		}

		var vars = map[string]interface{}{
			"CertificationPhoto": cert,
		}

		if err := tmpl.Execute(w, r, vars); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	})
}

// AdminCertification controller (/admin/photo/certification)
func AdminCertification() http.HandlerFunc {
	tmpl := templates.Must("admin/certification.html")
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		// View status
		var view = r.FormValue("view")
		if view == "" {
			view = "pending"
		}

		// Get the current user.
		currentUser, err := session.CurrentUser(r)
		if err != nil {
			session.FlashError(w, r, "Couldn't get CurrentUser: %s", err)
		}

		// Scope check based on view.
		switch view {
		case "pending":
			// Scope check.
			if !currentUser.HasAdminScope(config.ScopeCertificationApprove) {
				session.FlashError(w, r, "Missing admin scope: %s", config.ScopeCertificationApprove)
				templates.Redirect(w, "/admin")
				return
			}
		case "approved", "rejected":
			// Scope check.
			if !currentUser.HasAdminScope(config.ScopeCertificationList) {
				session.FlashError(w, r, "Missing admin scope: %s", config.ScopeCertificationList)
				templates.Redirect(w, "/admin")
				return
			}
		}

		// Short circuit the GET view for username/email search (exact match)
		if username := r.FormValue("username"); username != "" {
			// Scope check.
			if !currentUser.HasAdminScope(config.ScopeCertificationView) {
				session.FlashError(w, r, "Missing admin scope: %s", config.ScopeCertificationView)
				templates.Redirect(w, "/admin")
				return
			}

			user, err := models.FindUser(username)
			if err != nil {
				session.FlashError(w, r, "Username or email '%s' not found.", username)
				templates.Redirect(w, r.URL.Path)
				return
			}

			cert, err := models.GetCertificationPhoto(user.ID)
			if err != nil {
				session.FlashError(w, r, "Couldn't get their certification photo: %s", err)
				templates.Redirect(w, r.URL.Path)
				return
			}

			var vars = map[string]interface{}{
				"View":      view,
				"Photos":    []*models.CertificationPhoto{cert},
				"UserMap":   &models.UserMap{user.ID: user},
				"FoundUser": user,
			}
			if err := tmpl.Execute(w, r, vars); err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
			}
			return
		}

		// Making a verdict?
		if r.Method == http.MethodPost {
			// Scope check.
			if !currentUser.HasAdminScope(config.ScopeCertificationApprove) {
				session.FlashError(w, r, "Missing admin scope: %s", config.ScopeCertificationApprove)
				templates.Redirect(w, r.URL.Path)
				return
			}

			var (
				comment = r.PostFormValue("comment")
				verdict = r.PostFormValue("verdict")
			)

			userID, err := strconv.Atoi(r.PostFormValue("user_id"))
			if err != nil {
				session.FlashError(w, r, "Invalid user_id data type.")
				templates.Redirect(w, r.URL.Path)
				return
			}

			// Look up the user in case we'll toggle their Certified state.
			user, err := models.GetUser(uint64(userID))
			if err != nil {
				session.FlashError(w, r, "Couldn't get user ID %d: %s", userID, err)
				templates.Redirect(w, r.URL.Path)
				return
			}

			// Look up this photo.
			cert, err := models.GetCertificationPhoto(uint64(userID))
			if err != nil {
				session.FlashError(w, r, "Couldn't get certification photo.")
				templates.Redirect(w, r.URL.Path)
				return
			} else if cert.Filename == "" {
				session.FlashError(w, r, "That photo has no filename anymore??")
				templates.Redirect(w, r.URL.Path)
				return
			}

			switch verdict {
			case "reject":
				if comment == "" {
					session.FlashError(w, r, "An admin comment is required when rejecting a photo.")
				} else {
					cert.Status = models.CertificationPhotoRejected
					cert.AdminComment = comment
					if comment == "(ignore)" || comment == "(secondary)" {
						cert.AdminComment = ""
					}

					// With a secondary photo ID? Remove the photo ID immediately.
					if cert.SecondaryFilename != "" {
						// Delete it immediately.
						if err := photo.Delete(cert.SecondaryFilename); err != nil {
							session.FlashError(w, r, "Failed to delete old secondary ID cert photo for %s (%s): %s", currentUser.Username, cert.SecondaryFilename, err)
						}
						cert.SecondaryFilename = ""
						cert.SecondaryVerified = false
					}

					if err := cert.Save(); err != nil {
						session.FlashError(w, r, "Failed to save CertificationPhoto: %s", err)
						templates.Redirect(w, r.URL.Path)
						return
					}

					// Uncertify the user just in case.
					user.Certified = false
					user.Save()

					// Log the change.
					models.LogEvent(user, currentUser, models.ChangeLogRejected, "certification_photos", user.ID, "Rejected the certification photo with comment: "+comment)

					// Kick them from the chat room if they are online.
					if _, err := chat.MaybeDisconnectUser(user); err != nil {
						log.Error("chat.MaybeDisconnectUser(%s#%d): %s", user.Username, user.ID, err)
					}

					// Did we silently ignore it?
					if comment == "(ignore)" {
						session.FlashError(w, r, "The certification photo was ignored with no comment, and will not notify the sender.")
						templates.Redirect(w, r.URL.Path)
						return
					}

					// Secondary verification required: the user will be asked to upload a blacked-out
					// photo ID to be certified again.
					if comment == "(secondary)" {
						cert.Status = models.CertificationPhotoSecondary
						cert.SecondaryNeeded = true
						cert.SecondaryVerified = false
						if err := cert.Save(); err != nil {
							log.Error("Error saving cert photo: %s", err)
						}

						// Notify the user about this rejection.
						notif := &models.Notification{
							UserID:    user.ID,
							AboutUser: *user,
							Type:      models.NotificationCertSecondary,
							Message:   "A secondary form of photo ID is requested. Please [click here](/photo/certification) to learn more.",
						}
						if err := models.CreateNotification(notif); err != nil {
							log.Error("Couldn't create rejection notification: %s", err)
						}

						// Notify the user via email.
						if err := mail.Send(mail.Message{
							To:       user.Email,
							Subject:  "Regarding your nonshy certification photo",
							Template: "email/certification_secondary.html",
							Data: map[string]interface{}{
								"Username":     user.Username,
								"AdminComment": comment,
								"URL":          config.Current.BaseURL + "/photo/certification",
							},
						}); err != nil {
							session.FlashError(w, r, "Note: failed to email user about the rejection: %s", err)
						}

						session.Flash(w, r, "The user will be asked to provide a secondary form of ID.")
						templates.Redirect(w, r.URL.Path)
						return
					}

					// Notify the user about this rejection.
					notif := &models.Notification{
						UserID:    user.ID,
						AboutUser: *user,
						Type:      models.NotificationCertRejected,
						Message:   comment,
					}
					if err := models.CreateNotification(notif); err != nil {
						log.Error("Couldn't create rejection notification: %s", err)
					}

					// Notify the user via email.
					if err := mail.LockSending("cert_rejected", user.Email, config.EmailDebounceDefault); err == nil {
						if err := mail.Send(mail.Message{
							To:       user.Email,
							Subject:  "Your certification photo has been denied",
							Template: "email/certification_rejected.html",
							Data: map[string]interface{}{
								"Username":     user.Username,
								"AdminComment": comment,
								"URL":          config.Current.BaseURL + "/photo/certification",
							},
						}); err != nil {
							session.FlashError(w, r, "Note: failed to email user about the rejection: %s", err)
						}
					} else {
						log.Error("LockSending: cert_rejected e-mail is not sent to %s: one was sent recently", user.Email)
					}
				}

				session.Flash(w, r, "Certification photo rejected!")
			case "approve":
				cert.Status = models.CertificationPhotoApproved
				cert.AdminComment = ""

				// With a secondary photo ID?
				if cert.SecondaryFilename != "" {
					// Move the original photo into cold storage.
					coldStorageFilename := fmt.Sprintf(
						"photoID-%d-%s-%d.jpg",
						user.ID,
						user.Username,
						time.Now().Unix(),
					)
					if err := coldstorage.FileToColdStorage(
						photo.DiskPath(cert.SecondaryFilename),
						coldStorageFilename,
						config.Current.Encryption.ColdStorageRSAPublicKey,
					); err != nil {
						session.FlashError(w, r, "Failed to move to cold storage: %s", err)
						templates.Redirect(w, r.URL.Path)
						return
					} else {
						session.Flash(w, r, "Note: the secondary photo ID was encrypted to cold storage @ %s", coldStorageFilename)
					}

					// Delete it immediately.
					if err := photo.Delete(cert.SecondaryFilename); err != nil {
						session.FlashError(w, r, "Failed to delete old secondary ID cert photo for %s (%s): %s", currentUser.Username, cert.SecondaryFilename, err)
					}
					cert.SecondaryFilename = ""
					cert.SecondaryVerified = true
				}

				if err := cert.Save(); err != nil {
					session.FlashError(w, r, "Failed to save CertificationPhoto: %s", err)
					templates.Redirect(w, r.URL.Path)
					return
				}

				// Certify the user!
				user.Certified = true
				user.Save()

				// Notify the user about this approval.
				notif := &models.Notification{
					UserID:    user.ID,
					AboutUser: *user,
					Type:      models.NotificationCertApproved,
				}
				if err := models.CreateNotification(notif); err != nil {
					log.Error("Couldn't create approval notification: %s", err)
				}

				// Notify the user via email.
				if err := mail.LockSending("cert_approved", user.Email, config.EmailDebounceDefault); err == nil {
					if err := mail.Send(mail.Message{
						To:       user.Email,
						Subject:  "Your certification photo has been approved!",
						Template: "email/certification_approved.html",
						Data: map[string]interface{}{
							"Username": user.Username,
							"URL":      config.Current.BaseURL,
						},
					}); err != nil {
						session.FlashError(w, r, "Note: failed to email user about the approval: %s", err)
					}
				} else {
					log.Error("LockSending: cert_approved e-mail is not sent to %s: one was sent recently", user.Email)
				}

				// Log the change.
				models.LogEvent(user, currentUser, models.ChangeLogApproved, "certification_photos", user.ID, "Approved the certification photo.")

				session.Flash(w, r, "Certification photo approved!")
			default:
				session.FlashError(w, r, "Unsupported verdict option: %s", verdict)
			}
			templates.Redirect(w, r.URL.Path)
			return
		}

		// Get the pending photos.
		pager := &models.Pagination{
			Page:    1,
			PerPage: config.PageSizeAdminCertification,
			Sort:    "updated_at desc",
		}
		pager.ParsePage(r)
		photos, err := models.CertificationPhotosNeedingApproval(models.CertificationPhotoStatus(view), pager)
		if err != nil {
			session.FlashError(w, r, "Couldn't load certification photos from DB: %s", err)
		}

		// Map user IDs and GeoIP insights.
		var (
			userIDs     = []uint64{}
			ipAddresses = []string{}
		)
		for _, p := range photos {
			userIDs = append(userIDs, p.UserID)
			ipAddresses = append(ipAddresses, p.IPAddress)
		}
		insightsMap := geoip.MapInsights(ipAddresses)
		userMap, err := models.MapUsers(currentUser, userIDs)
		if err != nil {
			session.FlashError(w, r, "Couldn't map user IDs: %s", err)
		}

		var vars = map[string]interface{}{
			"View":        view,
			"Photos":      photos,
			"UserMap":     userMap,
			"InsightsMap": insightsMap,
			"Pager":       pager,
		}
		if err := tmpl.Execute(w, r, vars); err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}
	})
}