package state

import (
	"context"
	"crypto/hmac"
	"crypto/sha256"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"log"
	"log/slog"
	"net/http"
	"strings"
	"time"

	comatproto "github.com/bluesky-social/indigo/api/atproto"
	"github.com/bluesky-social/indigo/atproto/syntax"
	lexutil "github.com/bluesky-social/indigo/lex/util"
	securejoin "github.com/cyphar/filepath-securejoin"
	"github.com/go-chi/chi/v5"
	tangled "github.com/sotangled/tangled/api/tangled"
	"github.com/sotangled/tangled/appview"
	"github.com/sotangled/tangled/appview/auth"
	"github.com/sotangled/tangled/appview/db"
	"github.com/sotangled/tangled/appview/pages"
	"github.com/sotangled/tangled/jetstream"
	"github.com/sotangled/tangled/rbac"
)

type State struct {
	db       *db.DB
	auth     *auth.Auth
	enforcer *rbac.Enforcer
	tidClock *syntax.TIDClock
	pages    *pages.Pages
	resolver *appview.Resolver
	jc       *jetstream.JetstreamClient
	config   *appview.Config
}

func Make(config *appview.Config) (*State, error) {
	d, err := db.Make(config.DbPath)
	if err != nil {
		return nil, err
	}

	auth, err := auth.Make(config.CookieSecret)
	if err != nil {
		return nil, err
	}

	enforcer, err := rbac.NewEnforcer(config.DbPath)
	if err != nil {
		return nil, err
	}

	clock := syntax.NewTIDClock(0)

	pgs := pages.NewPages()

	resolver := appview.NewResolver()

	wrapper := db.DbWrapper{d}
	jc, err := jetstream.NewJetstreamClient("appview", []string{tangled.GraphFollowNSID}, nil, slog.Default(), wrapper, false)
	if err != nil {
		return nil, fmt.Errorf("failed to create jetstream client: %w", err)
	}
	err = jc.StartJetstream(context.Background(), jetstreamIngester(wrapper))
	if err != nil {
		return nil, fmt.Errorf("failed to start jetstream watcher: %w", err)
	}

	state := &State{
		d,
		auth,
		enforcer,
		clock,
		pgs,
		resolver,
		jc,
		config,
	}

	return state, nil
}

func (s *State) TID() string {
	return s.tidClock.Next().String()
}

func (s *State) Login(w http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	switch r.Method {
	case http.MethodGet:
		err := s.pages.Login(w, pages.LoginParams{})
		if err != nil {
			log.Printf("rendering login page: %s", err)
		}

		return
	case http.MethodPost:
		handle := strings.TrimPrefix(r.FormValue("handle"), "@")
		appPassword := r.FormValue("app_password")

		resolved, err := s.resolver.ResolveIdent(ctx, handle)
		if err != nil {
			log.Println("failed to resolve handle:", err)
			s.pages.Notice(w, "login-msg", fmt.Sprintf("\"%s\" is an invalid handle.", handle))
			return
		}

		atSession, err := s.auth.CreateInitialSession(ctx, resolved, appPassword)
		if err != nil {
			s.pages.Notice(w, "login-msg", "Invalid handle or password.")
			return
		}
		sessionish := auth.CreateSessionWrapper{ServerCreateSession_Output: atSession}

		err = s.auth.StoreSession(r, w, &sessionish, resolved.PDSEndpoint())
		if err != nil {
			s.pages.Notice(w, "login-msg", "Failed to login, try again later.")
			return
		}

		log.Printf("successfully saved session for %s (%s)", atSession.Handle, atSession.Did)

		did := resolved.DID.String()
		defaultKnot := "knot1.tangled.sh"

		go func() {
			log.Printf("adding %s to default knot", did)
			err = s.enforcer.AddMember(defaultKnot, did)
			if err != nil {
				log.Println("failed to add user to knot1.tangled.sh: ", err)
				return
			}
			err = s.enforcer.E.SavePolicy()
			if err != nil {
				log.Println("failed to add user to knot1.tangled.sh: ", err)
				return
			}

			secret, err := db.GetRegistrationKey(s.db, defaultKnot)
			if err != nil {
				log.Println("failed to get registration key for knot1.tangled.sh")
				return
			}
			signedClient, err := NewSignedClient(defaultKnot, secret, s.config.Dev)
			resp, err := signedClient.AddMember(did)
			if err != nil {
				log.Println("failed to add user to knot1.tangled.sh: ", err)
				return
			}

			if resp.StatusCode != http.StatusNoContent {
				log.Println("failed to add user to knot1.tangled.sh: ", resp.StatusCode)
				return
			}
		}()

		s.pages.HxRedirect(w, "/")
		return
	}
}

func (s *State) Logout(w http.ResponseWriter, r *http.Request) {
	s.auth.ClearSession(r, w)
	http.Redirect(w, r, "/login", http.StatusTemporaryRedirect)
}

func (s *State) Timeline(w http.ResponseWriter, r *http.Request) {
	user := s.auth.GetUser(r)

	timeline, err := db.MakeTimeline(s.db)
	if err != nil {
		log.Println(err)
		s.pages.Notice(w, "timeline", "Uh oh! Failed to load timeline.")
	}

	var didsToResolve []string
	for _, ev := range timeline {
		if ev.Repo != nil {
			didsToResolve = append(didsToResolve, ev.Repo.Did)
		}
		if ev.Follow != nil {
			didsToResolve = append(didsToResolve, ev.Follow.UserDid, ev.Follow.SubjectDid)
		}
		if ev.Star != nil {
			didsToResolve = append(didsToResolve, ev.Star.StarredByDid, ev.Star.Repo.Did)
		}
	}

	resolvedIds := s.resolver.ResolveIdents(r.Context(), didsToResolve)
	didHandleMap := make(map[string]string)
	for _, identity := range resolvedIds {
		if !identity.Handle.IsInvalidHandle() {
			didHandleMap[identity.DID.String()] = fmt.Sprintf("@%s", identity.Handle.String())
		} else {
			didHandleMap[identity.DID.String()] = identity.DID.String()
		}
	}

	s.pages.Timeline(w, pages.TimelineParams{
		LoggedInUser: user,
		Timeline:     timeline,
		DidHandleMap: didHandleMap,
	})

	return
}

// requires auth
func (s *State) RegistrationKey(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		// list open registrations under this did

		return
	case http.MethodPost:
		session, err := s.auth.Store.Get(r, appview.SessionName)
		if err != nil || session.IsNew {
			log.Println("unauthorized attempt to generate registration key")
			http.Error(w, "Forbidden", http.StatusUnauthorized)
			return
		}

		did := session.Values[appview.SessionDid].(string)

		// check if domain is valid url, and strip extra bits down to just host
		domain := r.FormValue("domain")
		if domain == "" {
			http.Error(w, "Invalid form", http.StatusBadRequest)
			return
		}

		key, err := db.GenerateRegistrationKey(s.db, domain, did)

		if err != nil {
			log.Println(err)
			http.Error(w, "unable to register this domain", http.StatusNotAcceptable)
			return
		}

		w.Write([]byte(key))
	}
}

func (s *State) Keys(w http.ResponseWriter, r *http.Request) {
	user := chi.URLParam(r, "user")
	user = strings.TrimPrefix(user, "@")

	if user == "" {
		w.WriteHeader(http.StatusBadRequest)
		return
	}

	id, err := s.resolver.ResolveIdent(r.Context(), user)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}

	pubKeys, err := db.GetPublicKeys(s.db, id.DID.String())
	if err != nil {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	if len(pubKeys) == 0 {
		w.WriteHeader(http.StatusNotFound)
		return
	}

	for _, k := range pubKeys {
		key := strings.TrimRight(k.Key, "\n")
		w.Write([]byte(fmt.Sprintln(key)))
	}
}

// create a signed request and check if a node responds to that
func (s *State) InitKnotServer(w http.ResponseWriter, r *http.Request) {
	user := s.auth.GetUser(r)

	domain := chi.URLParam(r, "domain")
	if domain == "" {
		http.Error(w, "malformed url", http.StatusBadRequest)
		return
	}
	log.Println("checking ", domain)

	secret, err := db.GetRegistrationKey(s.db, domain)
	if err != nil {
		log.Printf("no key found for domain %s: %s\n", domain, err)
		return
	}

	client, err := NewSignedClient(domain, secret, s.config.Dev)
	if err != nil {
		log.Println("failed to create client to ", domain)
	}

	resp, err := client.Init(user.Did)
	if err != nil {
		w.Write([]byte("no dice"))
		log.Println("domain was unreachable after 5 seconds")
		return
	}

	if resp.StatusCode == http.StatusConflict {
		log.Println("status conflict", resp.StatusCode)
		w.Write([]byte("already registered, sorry!"))
		return
	}

	if resp.StatusCode != http.StatusNoContent {
		log.Println("status nok", resp.StatusCode)
		w.Write([]byte("no dice"))
		return
	}

	// verify response mac
	signature := resp.Header.Get("X-Signature")
	signatureBytes, err := hex.DecodeString(signature)
	if err != nil {
		return
	}

	expectedMac := hmac.New(sha256.New, []byte(secret))
	expectedMac.Write([]byte("ok"))

	if !hmac.Equal(expectedMac.Sum(nil), signatureBytes) {
		log.Printf("response body signature mismatch: %x\n", signatureBytes)
		return
	}

	tx, err := s.db.BeginTx(r.Context(), nil)
	if err != nil {
		log.Println("failed to start tx", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	defer func() {
		tx.Rollback()
		err = s.enforcer.E.LoadPolicy()
		if err != nil {
			log.Println("failed to rollback policies")
		}
	}()

	// mark as registered
	err = db.Register(tx, domain)
	if err != nil {
		log.Println("failed to register domain", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// set permissions for this did as owner
	reg, err := db.RegistrationByDomain(tx, domain)
	if err != nil {
		log.Println("failed to register domain", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// add basic acls for this domain
	err = s.enforcer.AddDomain(domain)
	if err != nil {
		log.Println("failed to setup owner of domain", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// add this did as owner of this domain
	err = s.enforcer.AddOwner(domain, reg.ByDid)
	if err != nil {
		log.Println("failed to setup owner of domain", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = tx.Commit()
	if err != nil {
		log.Println("failed to commit changes", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	err = s.enforcer.E.SavePolicy()
	if err != nil {
		log.Println("failed to update ACLs", err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.Write([]byte("check success"))
}

func (s *State) KnotServerInfo(w http.ResponseWriter, r *http.Request) {
	domain := chi.URLParam(r, "domain")
	if domain == "" {
		http.Error(w, "malformed url", http.StatusBadRequest)
		return
	}

	user := s.auth.GetUser(r)
	reg, err := db.RegistrationByDomain(s.db, domain)
	if err != nil {
		w.Write([]byte("failed to pull up registration info"))
		return
	}

	var members []string
	if reg.Registered != nil {
		members, err = s.enforcer.GetUserByRole("server:member", domain)
		if err != nil {
			w.Write([]byte("failed to fetch member list"))
			return
		}
	}

	ok, err := s.enforcer.IsServerOwner(user.Did, domain)
	isOwner := err == nil && ok

	p := pages.KnotParams{
		LoggedInUser: user,
		Registration: reg,
		Members:      members,
		IsOwner:      isOwner,
	}

	s.pages.Knot(w, p)
}

// get knots registered by this user
func (s *State) Knots(w http.ResponseWriter, r *http.Request) {
	// for now, this is just pubkeys
	user := s.auth.GetUser(r)
	registrations, err := db.RegistrationsByDid(s.db, user.Did)
	if err != nil {
		log.Println(err)
	}

	s.pages.Knots(w, pages.KnotsParams{
		LoggedInUser:  user,
		Registrations: registrations,
	})
}

// list members of domain, requires auth and requires owner status
func (s *State) ListMembers(w http.ResponseWriter, r *http.Request) {
	domain := chi.URLParam(r, "domain")
	if domain == "" {
		http.Error(w, "malformed url", http.StatusBadRequest)
		return
	}

	// list all members for this domain
	memberDids, err := s.enforcer.GetUserByRole("server:member", domain)
	if err != nil {
		w.Write([]byte("failed to fetch member list"))
		return
	}

	w.Write([]byte(strings.Join(memberDids, "\n")))
	return
}

// add member to domain, requires auth and requires invite access
func (s *State) AddMember(w http.ResponseWriter, r *http.Request) {
	domain := chi.URLParam(r, "domain")
	if domain == "" {
		http.Error(w, "malformed url", http.StatusBadRequest)
		return
	}

	memberDid := r.FormValue("member")
	if memberDid == "" {
		http.Error(w, "malformed form", http.StatusBadRequest)
		return
	}

	memberIdent, err := s.resolver.ResolveIdent(r.Context(), memberDid)
	if err != nil {
		w.Write([]byte("failed to resolve member did to a handle"))
		return
	}
	log.Printf("adding %s to %s\n", memberIdent.Handle.String(), domain)

	// announce this relation into the firehose, store into owners' pds
	client, _ := s.auth.AuthorizedClient(r)
	currentUser := s.auth.GetUser(r)
	addedAt := time.Now().Format(time.RFC3339)
	resp, err := comatproto.RepoPutRecord(r.Context(), client, &comatproto.RepoPutRecord_Input{
		Collection: tangled.KnotMemberNSID,
		Repo:       currentUser.Did,
		Rkey:       s.TID(),
		Record: &lexutil.LexiconTypeDecoder{
			Val: &tangled.KnotMember{
				Member:  memberIdent.DID.String(),
				Domain:  domain,
				AddedAt: &addedAt,
			}},
	})

	// invalid record
	if err != nil {
		log.Printf("failed to create record: %s", err)
		return
	}
	log.Println("created atproto record: ", resp.Uri)

	secret, err := db.GetRegistrationKey(s.db, domain)
	if err != nil {
		log.Printf("no key found for domain %s: %s\n", domain, err)
		return
	}

	ksClient, err := NewSignedClient(domain, secret, s.config.Dev)
	if err != nil {
		log.Println("failed to create client to ", domain)
		return
	}

	ksResp, err := ksClient.AddMember(memberIdent.DID.String())
	if err != nil {
		log.Printf("failed to make request to %s: %s", domain, err)
		return
	}

	if ksResp.StatusCode != http.StatusNoContent {
		w.Write([]byte(fmt.Sprint("knotserver failed to add member: ", err)))
		return
	}

	err = s.enforcer.AddMember(domain, memberIdent.DID.String())
	if err != nil {
		w.Write([]byte(fmt.Sprint("failed to add member: ", err)))
		return
	}

	w.Write([]byte(fmt.Sprint("added member: ", memberIdent.Handle.String())))
}

func (s *State) RemoveMember(w http.ResponseWriter, r *http.Request) {
}

func (s *State) NewRepo(w http.ResponseWriter, r *http.Request) {
	switch r.Method {
	case http.MethodGet:
		user := s.auth.GetUser(r)
		knots, err := s.enforcer.GetDomainsForUser(user.Did)
		if err != nil {
			s.pages.Notice(w, "repo", "Invalid user account.")
			return
		}

		s.pages.NewRepo(w, pages.NewRepoParams{
			LoggedInUser: user,
			Knots:        knots,
		})

	case http.MethodPost:
		user := s.auth.GetUser(r)

		domain := r.FormValue("domain")
		if domain == "" {
			s.pages.Notice(w, "repo", "Invalid form submission—missing knot domain.")
			return
		}

		repoName := r.FormValue("name")
		if repoName == "" {
			s.pages.Notice(w, "repo", "Repository name cannot be empty.")
			return
		}

		// Check for valid repository name (GitHub-like rules)
		// No spaces, only alphanumeric characters, dashes, and underscores
		for _, char := range repoName {
			if !((char >= 'a' && char <= 'z') ||
				(char >= 'A' && char <= 'Z') ||
				(char >= '0' && char <= '9') ||
				char == '-' || char == '_' || char == '.') {
				s.pages.Notice(w, "repo", "Repository name can only contain alphanumeric characters, periods, hyphens, and underscores.")
				return
			}
		}

		defaultBranch := r.FormValue("branch")
		if defaultBranch == "" {
			defaultBranch = "main"
		}

		description := r.FormValue("description")

		ok, err := s.enforcer.E.Enforce(user.Did, domain, domain, "repo:create")
		if err != nil || !ok {
			s.pages.Notice(w, "repo", "You do not have permission to create a repo in this knot.")
			return
		}

		existingRepo, err := db.GetRepo(s.db, user.Did, repoName)
		if err == nil && existingRepo != nil {
			s.pages.Notice(w, "repo", fmt.Sprintf("A repo by this name already exists on %s", existingRepo.Knot))
			return
		}

		secret, err := db.GetRegistrationKey(s.db, domain)
		if err != nil {
			s.pages.Notice(w, "repo", fmt.Sprintf("No registration key found for knot %s.", domain))
			return
		}

		client, err := NewSignedClient(domain, secret, s.config.Dev)
		if err != nil {
			s.pages.Notice(w, "repo", "Failed to connect to knot server.")
			return
		}

		rkey := s.TID()
		repo := &db.Repo{
			Did:         user.Did,
			Name:        repoName,
			Knot:        domain,
			Rkey:        rkey,
			Description: description,
		}

		xrpcClient, _ := s.auth.AuthorizedClient(r)

		addedAt := time.Now().Format(time.RFC3339)
		atresp, err := comatproto.RepoPutRecord(r.Context(), xrpcClient, &comatproto.RepoPutRecord_Input{
			Collection: tangled.RepoNSID,
			Repo:       user.Did,
			Rkey:       rkey,
			Record: &lexutil.LexiconTypeDecoder{
				Val: &tangled.Repo{
					Knot:    repo.Knot,
					Name:    repoName,
					AddedAt: &addedAt,
					Owner:   user.Did,
				}},
		})
		if err != nil {
			log.Printf("failed to create record: %s", err)
			s.pages.Notice(w, "repo", "Failed to announce repository creation.")
			return
		}
		log.Println("created repo record: ", atresp.Uri)

		tx, err := s.db.BeginTx(r.Context(), nil)
		if err != nil {
			log.Println(err)
			s.pages.Notice(w, "repo", "Failed to save repository information.")
			return
		}
		defer func() {
			tx.Rollback()
			err = s.enforcer.E.LoadPolicy()
			if err != nil {
				log.Println("failed to rollback policies")
			}
		}()

		resp, err := client.NewRepo(user.Did, repoName, defaultBranch)
		if err != nil {
			s.pages.Notice(w, "repo", "Failed to create repository on knot server.")
			return
		}

		switch resp.StatusCode {
		case http.StatusConflict:
			s.pages.Notice(w, "repo", "A repository with that name already exists.")
			return
		case http.StatusInternalServerError:
			s.pages.Notice(w, "repo", "Failed to create repository on knot. Try again later.")
		case http.StatusNoContent:
			// continue
		}

		repo.AtUri = atresp.Uri
		err = db.AddRepo(tx, repo)
		if err != nil {
			log.Println(err)
			s.pages.Notice(w, "repo", "Failed to save repository information.")
			return
		}

		// acls
		p, _ := securejoin.SecureJoin(user.Did, repoName)
		err = s.enforcer.AddRepo(user.Did, domain, p)
		if err != nil {
			log.Println(err)
			s.pages.Notice(w, "repo", "Failed to set up repository permissions.")
			return
		}

		err = tx.Commit()
		if err != nil {
			log.Println("failed to commit changes", err)
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		err = s.enforcer.E.SavePolicy()
		if err != nil {
			log.Println("failed to update ACLs", err)
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		s.pages.HxLocation(w, fmt.Sprintf("/@%s/%s", user.Handle, repoName))
		return
	}
}

func (s *State) ProfilePage(w http.ResponseWriter, r *http.Request) {
	didOrHandle := chi.URLParam(r, "user")
	if didOrHandle == "" {
		http.Error(w, "Bad request", http.StatusBadRequest)
		return
	}

	ident, err := s.resolver.ResolveIdent(r.Context(), didOrHandle)
	if err != nil {
		log.Printf("resolving identity: %s", err)
		w.WriteHeader(http.StatusNotFound)
		return
	}

	repos, err := db.GetAllReposByDid(s.db, ident.DID.String())
	if err != nil {
		log.Printf("getting repos for %s: %s", ident.DID.String(), err)
	}

	collaboratingRepos, err := db.CollaboratingIn(s.db, ident.DID.String())
	if err != nil {
		log.Printf("getting collaborating repos for %s: %s", ident.DID.String(), err)
	}
	var didsToResolve []string
	for _, r := range collaboratingRepos {
		didsToResolve = append(didsToResolve, r.Did)
	}
	resolvedIds := s.resolver.ResolveIdents(r.Context(), didsToResolve)
	didHandleMap := make(map[string]string)
	for _, identity := range resolvedIds {
		if !identity.Handle.IsInvalidHandle() {
			didHandleMap[identity.DID.String()] = fmt.Sprintf("@%s", identity.Handle.String())
		} else {
			didHandleMap[identity.DID.String()] = identity.DID.String()
		}
	}

	followers, following, err := db.GetFollowerFollowing(s.db, ident.DID.String())
	if err != nil {
		log.Printf("getting follow stats repos for %s: %s", ident.DID.String(), err)
	}

	loggedInUser := s.auth.GetUser(r)
	followStatus := db.IsNotFollowing
	if loggedInUser != nil {
		followStatus = db.GetFollowStatus(s.db, loggedInUser.Did, ident.DID.String())
	}

	profileAvatarUri, err := GetAvatarUri(ident.DID.String())
	if err != nil {
		log.Println("failed to fetch bsky avatar", err)
	}

	s.pages.ProfilePage(w, pages.ProfilePageParams{
		LoggedInUser:       loggedInUser,
		UserDid:            ident.DID.String(),
		UserHandle:         ident.Handle.String(),
		Repos:              repos,
		CollaboratingRepos: collaboratingRepos,
		ProfileStats: pages.ProfileStats{
			Followers: followers,
			Following: following,
		},
		FollowStatus: db.FollowStatus(followStatus),
		DidHandleMap: didHandleMap,
		AvatarUri:    profileAvatarUri,
	})
}

func GetAvatarUri(did string) (string, error) {
	recordURL := fmt.Sprintf("https://bsky.social/xrpc/com.atproto.repo.getRecord?repo=%s&collection=app.bsky.actor.profile&rkey=self", did)

	recordResp, err := http.Get(recordURL)
	if err != nil {
		return "", err
	}
	defer recordResp.Body.Close()

	if recordResp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("getRecord API returned status code %d", recordResp.StatusCode)
	}

	var profileResp map[string]any
	if err := json.NewDecoder(recordResp.Body).Decode(&profileResp); err != nil {
		return "", err
	}

	value, ok := profileResp["value"].(map[string]any)
	if !ok {
		log.Println(profileResp)
		return "", fmt.Errorf("no value found for handle %s", did)
	}

	avatar, ok := value["avatar"].(map[string]any)
	if !ok {
		log.Println(profileResp)
		return "", fmt.Errorf("no avatar found for handle %s", did)
	}

	blobRef, ok := avatar["ref"].(map[string]any)
	if !ok {
		log.Println(profileResp)
		return "", fmt.Errorf("no ref found for handle %s", did)
	}

	link, ok := blobRef["$link"].(string)
	if !ok {
		log.Println(profileResp)
		return "", fmt.Errorf("no link found for handle %s", did)
	}

	return fmt.Sprintf("https://cdn.bsky.app/img/feed_thumbnail/plain/%s/%s", did, link), nil
}