package api

import (
	"bytes"
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"testing"

	"geniusrun/backend/internal/auth"
	authmock "geniusrun/backend/internal/auth/mock"
	"geniusrun/backend/internal/garmin"
	"geniusrun/backend/internal/store"
)

// doJSONAs is doJSON but for an explicit session Sub, for tests that need
// two distinct logged-in users against the same server (doJSON itself
// always mints a cookie for Sub: "test-user", the identity newTestServer
// pre-provisions).
func doJSONAs(t *testing.T, handler http.Handler, sub, method, path string, body any) *httptest.ResponseRecorder {
	t.Helper()
	var reader *bytes.Reader
	if body != nil {
		b, err := json.Marshal(body)
		if err != nil {
			t.Fatalf("marshal request body: %v", err)
		}
		reader = bytes.NewReader(b)
	} else {
		reader = bytes.NewReader(nil)
	}
	req := httptest.NewRequest(method, path, reader)
	req.Header.Set("Content-Type", "application/json")
	cookie, err := auth.MintSessionCookie(auth.Claims{Sub: sub, Name: sub, Email: sub + "@example.com"}, testSessionConfig.Secret, testSessionConfig.Duration, testSessionConfig.Secure)
	if err != nil {
		t.Fatalf("mint test session cookie: %v", err)
	}
	req.AddCookie(cookie)
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	return rec
}

func TestIsolation_AssignCannotTargetOtherUsersActivity(t *testing.T) {
	s, db, _ := newTestServer(t) // provisions "test-user" (userA)
	userB, err := db.ProvisionUser(newCtx(), "user-b", "B")
	if err != nil {
		t.Fatalf("ProvisionUser(b): %v", err)
	}

	userA, found, err := db.GetUserBySub(newCtx(), "test-user")
	if err != nil || !found {
		t.Fatalf("GetUserBySub(test-user): found=%v err=%v", found, err)
	}
	activityID, err := db.UpsertActivity(newCtx(), userA.ID, store.Activity{GarminActivityID: 1, StartTimeUTC: "2026-07-11 06:00:00", RawJSON: "{}"})
	if err != nil {
		t.Fatalf("UpsertActivity: %v", err)
	}

	kindsB, err := db.ListWorkoutKinds(newCtx(), userB, false)
	if err != nil || len(kindsB) == 0 {
		t.Fatalf("ListWorkoutKinds(b): len=%d err=%v", len(kindsB), err)
	}
	kindB := kindsB[0]
	if kindB.Name == "Race" { // Race is rejected before the ownership check
		kindB = kindsB[1]
	}

	// userB, given userA's real activity id (and a kind userB legitimately
	// owns), must not be able to write an assignment onto it.
	rec := doJSONAs(t, s.Router(), "user-b", http.MethodPost, "/api/activities/"+itoa(activityID)+"/assign", map[string]any{"workout_kind_id": kindB.ID})
	if rec.Code == http.StatusOK {
		t.Fatalf("userB assigning userA's activity succeeded (status %d), body = %s", rec.Code, rec.Body.String())
	}
	if _, ok, err := db.CurrentAssignment(newCtx(), userA.ID, activityID); err != nil {
		t.Fatalf("CurrentAssignment: %v", err)
	} else if ok {
		t.Fatalf("userB's rejected assign still created an assignment on userA's activity")
	}
}

func TestIsolation_WorkoutKindUpdateCannotTargetOtherUsersKind(t *testing.T) {
	s, db, _ := newTestServer(t) // provisions "test-user" (userA)
	if _, err := db.ProvisionUser(newCtx(), "user-b", "B"); err != nil {
		t.Fatalf("ProvisionUser(b): %v", err)
	}
	userA, _, _ := db.GetUserBySub(newCtx(), "test-user")
	kindsA, err := db.ListWorkoutKinds(newCtx(), userA.ID, false)
	if err != nil || len(kindsA) == 0 {
		t.Fatalf("ListWorkoutKinds(a): len=%d err=%v", len(kindsA), err)
	}
	targetID := kindsA[0].ID
	originalName := kindsA[0].Name

	router := s.Router()
	rec := doJSONAs(t, router, "user-b", http.MethodPut, "/api/workout-kinds/"+itoa(targetID), map[string]any{
		"name": "Hijacked",
		"rule": json.RawMessage(`{"match":"all","conditions":[]}`),
	})
	if rec.Code != http.StatusNotFound {
		t.Fatalf("userB updating userA's kind status = %d, want 404, body = %s", rec.Code, rec.Body.String())
	}

	rec = doJSON(t, router, http.MethodGet, "/api/workout-kinds/"+itoa(targetID), nil)
	var got workoutKindResponse
	json.Unmarshal(rec.Body.Bytes(), &got)
	if got.Name != originalName {
		t.Fatalf("userA's kind name changed to %q despite userB's update being rejected", got.Name)
	}
}

func TestIsolation_ActivitiesListOnlyShowsOwnActivities(t *testing.T) {
	s, db, _ := newTestServer(t) // provisions "test-user" (userA)
	userB, err := db.ProvisionUser(newCtx(), "user-b", "B")
	if err != nil {
		t.Fatalf("ProvisionUser(b): %v", err)
	}
	if _, err := db.UpsertActivity(newCtx(), userB, store.Activity{GarminActivityID: 42, StartTimeUTC: "2026-07-11 06:00:00", RawJSON: "{}"}); err != nil {
		t.Fatalf("UpsertActivity(b): %v", err)
	}
	if _, err := db.InsertKindAssignment(newCtx(), userB, store.KindAssignment{
		ActivityID: func() int64 {
			acts, _ := db.ListActivities(newCtx(), userB, store.ActivityFilter{})
			return acts[0].ID
		}(),
		AssignmentSource: store.AssignmentSourceRuleEngine, Status: store.AssignmentStatusNeedsReview, CandidateKindsJSON: "[]",
	}); err != nil {
		t.Fatalf("InsertKindAssignment(b): %v", err)
	}

	rec := doJSON(t, s.Router(), http.MethodGet, "/api/activities/", nil) // as userA
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, body = %s", rec.Code, rec.Body.String())
	}
	var page struct {
		Items []map[string]any `json:"items"`
		Total int              `json:"total"`
	}
	json.Unmarshal(rec.Body.Bytes(), &page)
	if page.Total != 0 || len(page.Items) != 0 {
		t.Fatalf("expected userA's activities list to be empty (the only assignment belongs to userB), got total=%d items=%d", page.Total, len(page.Items))
	}
}

func TestIsolation_RequireProvisionedUser_BlocksDataRoutesUntilSetup(t *testing.T) {
	db, err := store.Open(t.TempDir() + "/isolation_test.db")
	if err != nil {
		t.Fatalf("store.Open: %v", err)
	}
	defer db.Close()
	m := &garmin.MockClient{}
	s := NewServer(db, func(garmin.ClientConfig) garmin.Client { return m }, garmin.ClientConfig{}, garmin.SyncConfig{}, &authmock.Verifier{}, testSessionConfig)

	rec := doJSON(t, s.Router(), http.MethodGet, "/api/activities/", nil) // "test-user" sub, never provisioned
	if rec.Code != http.StatusForbidden {
		t.Fatalf("status = %d, want 403 (no profile provisioned yet), body = %s", rec.Code, rec.Body.String())
	}
}

// TestIsolation_DeleteProfileOnlyDeletesOwnAccount confirms one user
// deleting their own profile never touches another user's account, even
// though DeleteUser is keyed purely by the session-resolved userID.
func TestIsolation_DeleteProfileOnlyDeletesOwnAccount(t *testing.T) {
	s, db, userA := newTestServer(t) // provisions "test-user" (userA)
	if _, err := db.ProvisionUser(newCtx(), "user-b", "B"); err != nil {
		t.Fatalf("ProvisionUser(b): %v", err)
	}

	router := s.Router()
	rec := doJSONAs(t, router, "user-b", http.MethodDelete, "/api/profile", nil)
	if rec.Code != http.StatusNoContent {
		t.Fatalf("userB delete status = %d, body = %s", rec.Code, rec.Body.String())
	}

	if _, found, err := db.GetUserBySub(newCtx(), "user-b"); err != nil || found {
		t.Fatalf("expected userB gone after their own delete, found=%v err=%v", found, err)
	}
	u, found, err := db.GetUserBySub(newCtx(), "test-user")
	if err != nil || !found || u.ID != userA {
		t.Fatalf("expected userA to survive userB's deletion, found=%v err=%v id=%d want=%d", found, err, u.ID, userA)
	}
	rec = doJSON(t, router, http.MethodGet, "/api/profile", nil) // as userA
	if rec.Code != http.StatusOK {
		t.Fatalf("userA profile status after userB deleted themselves = %d, body = %s", rec.Code, rec.Body.String())
	}
}

// TestIsolation_GarminConnectedNeverLeaksAcrossUsers confirms one user's
// successful Garmin auth never flips garmin_connected for another user.
func TestIsolation_GarminConnectedNeverLeaksAcrossUsers(t *testing.T) {
	s, db, _ := newTestServer(t) // provisions "test-user" (userA)
	if _, err := db.ProvisionUser(newCtx(), "user-b", "B"); err != nil {
		t.Fatalf("ProvisionUser(b): %v", err)
	}

	router := s.Router()
	rec := doJSON(t, router, http.MethodPost, "/api/garmin/auth/login", nil) // as userA
	if rec.Code != http.StatusOK {
		t.Fatalf("auth/login status = %d, body = %s", rec.Code, rec.Body.String())
	}

	rec = doJSONAs(t, router, "user-b", http.MethodGet, "/api/session/me", nil)
	var meB sessionMeResponse
	unmarshalBody(t, rec, &meB)
	if meB.GarminConnected {
		t.Fatal("userA's successful Garmin auth leaked into userB's garmin_connected flag")
	}
}

// TestIsolation_SetupSessionsNeverLeakAcrossSubjects confirms one OIDC
// subject's pending ephemeral Garmin session is invisible to another
// subject -- e.g. subject B completing MFA must not accidentally continue
// subject A's in-progress attempt.
func TestIsolation_SetupSessionsNeverLeakAcrossSubjects(t *testing.T) {
	s, _, _ := newUnprovisionedServer(t)
	router := s.Router()

	rec := doJSON(t, router, http.MethodPost, "/api/setup/garmin/login", map[string]any{
		"garmin_email": "a@example.com", "garmin_password": "pw-a",
	})
	if rec.Code != http.StatusOK {
		t.Fatalf("login(a) status = %d, body = %s", rec.Code, rec.Body.String())
	}

	rec = doJSONAs(t, router, "user-b", http.MethodPost, "/api/setup/garmin/mfa", map[string]any{"code": "000000"})
	if rec.Code != http.StatusConflict {
		t.Fatalf("user-b mfa (no login attempt of their own) status = %d, want 409, body = %s", rec.Code, rec.Body.String())
	}
}