package api

import (
	"encoding/json"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strconv"

	"geniusrun/backend/internal/auth"
	"geniusrun/backend/internal/garmin"
)

// handleSetupGarminLogin authenticates against Garmin using an ephemeral,
// not-yet-persisted session keyed by the OIDC subject -- no users/profile
// row exists yet at this point (see setupSession in server.go).
func (s *Server) handleSetupGarminLogin(w http.ResponseWriter, r *http.Request) {
	claims, ok := auth.ClaimsFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "not authenticated")
		return
	}
	if _, found := userFromContext(r.Context()); found {
		writeError(w, http.StatusConflict, "profile already exists for this account")
		return
	}

	var body struct {
		GarminEmail    string `json:"garmin_email"`
		GarminPassword string `json:"garmin_password"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}
	if body.GarminEmail == "" || body.GarminPassword == "" {
		writeError(w, http.StatusBadRequest, "garmin_email and garmin_password are required")
		return
	}

	sess := s.replaceSetupSession(claims.Sub, body.GarminEmail, body.GarminPassword)
	res, err := sess.Client.Authenticate(r.Context())
	if err != nil {
		writeError(w, http.StatusBadGateway, err.Error())
		return
	}
	s.recordSetupAuthResult(claims.Sub, res)
	writeJSON(w, http.StatusOK, authResponse{Status: authStatusString(res.Status), Message: res.Message})
}

// handleSetupGarminMFA continues an in-progress ephemeral Garmin login
// (started by handleSetupGarminLogin) with an MFA code, on the same
// session/subprocess -- never replaces it.
func (s *Server) handleSetupGarminMFA(w http.ResponseWriter, r *http.Request) {
	claims, ok := auth.ClaimsFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "not authenticated")
		return
	}

	var body struct {
		Code string `json:"code"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}
	if body.Code == "" {
		writeError(w, http.StatusBadRequest, "code is required")
		return
	}

	sess, ok := s.setupSessionFor(claims.Sub)
	if !ok {
		writeError(w, http.StatusConflict, "no Garmin connection attempt in progress; connect again")
		return
	}
	res, err := sess.Client.CompleteMFA(r.Context(), body.Code)
	if err != nil {
		writeError(w, http.StatusBadGateway, err.Error())
		return
	}
	s.recordSetupAuthResult(claims.Sub, res)
	writeJSON(w, http.StatusOK, authResponse{Status: authStatusString(res.Status), Message: res.Message})
}

// handleSetupComplete is the single atomic commit point: only reachable
// once the ephemeral session for this subject last reported
// garmin.AuthSuccess. Provisions the account, persists the Garmin
// credentials, marks it connected, closes the ephemeral client, and
// renames its token-store directory into the permanent per-user path --
// the next real garminFor(ctx, userID) builds a fresh client from scratch
// against that now-permanent directory, whose subprocess's lazy
// startup-login resumes the just-renamed, still-valid session without
// needing to re-authenticate (a cheap local token-store resume, not a
// fresh Garmin login).
func (s *Server) handleSetupComplete(w http.ResponseWriter, r *http.Request) {
	claims, ok := auth.ClaimsFromContext(r.Context())
	if !ok {
		writeError(w, http.StatusUnauthorized, "not authenticated")
		return
	}
	if _, found := userFromContext(r.Context()); found {
		writeError(w, http.StatusConflict, "profile already exists for this account")
		return
	}

	var body struct {
		DisplayName string `json:"display_name"`
	}
	if err := json.NewDecoder(r.Body).Decode(&body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid request body")
		return
	}
	if body.DisplayName == "" {
		writeError(w, http.StatusBadRequest, "display_name is required")
		return
	}

	sess, ok := s.setupSessionFor(claims.Sub)
	if !ok || sess.Status != garmin.AuthSuccess {
		writeError(w, http.StatusConflict, "Garmin isn't connected yet -- connect before completing setup")
		return
	}

	userID, err := s.DB.ProvisionUser(r.Context(), claims.Sub, body.DisplayName)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	profile, err := s.DB.GetProfile(r.Context(), userID)
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	profile.GarminEmail = sess.Email
	profile.GarminPassword = sess.Password
	if err := s.DB.UpdateProfile(r.Context(), userID, profile); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if err := s.DB.MarkGarminConnected(r.Context(), userID); err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}

	// The ephemeral client's own garmin.Config.TokenStorePath was set once,
	// at construction time in replaceSetupSession, to the ephemeral
	// setup/{hash} directory being renamed below -- there's no setter to
	// correct it in place, so promoting this object into s.userGarmin would
	// leave a client whose subprocess respawns (e.g. on the very next
	// UpdateCredentials call from a Profile save) using that now-stale
	// path, recreating a setup/{hash} directory next to the real one.
	// Closing it here and leaving s.userGarmin empty for this user makes
	// the next garminFor(ctx, userID) call build a fresh client against the
	// correct, just-renamed {userID} directory instead -- its subprocess's
	// lazy startup-login resumes that session without a real Garmin
	// re-authentication.
	sess.Client.Close()

	s.mu.Lock()
	delete(s.setupGarmin, claims.Sub)
	s.userAuthStatus[userID] = sess.Status
	s.userAuthMessage[userID] = sess.Message
	s.mu.Unlock()

	if s.GarminBase.TokenStorePath != "" {
		oldDir := setupTokenStoreDir(s.GarminBase.TokenStorePath, claims.Sub)
		newDir := filepath.Join(s.GarminBase.TokenStorePath, strconv.FormatInt(userID, 10))
		if err := os.Rename(oldDir, newDir); err != nil && !os.IsNotExist(err) {
			log.Printf("api: rename setup token store dir for user %d: %v", userID, err)
		}
	}

	writeJSON(w, http.StatusOK, map[string]any{"user_id": userID, "display_name": body.DisplayName})
}