package db

import (
	"context"
	"net/http"
	"net/http/httptest"
	"strings"
	"testing"
	"time"
)

// setupSessionTestDB creates an in-memory SQLite database for testing
func setupSessionTestDB(t *testing.T) *SessionStore {
	t.Helper()
	// Use file::memory: with cache=shared to ensure all connections share the same in-memory DB
	db, err := InitDB("file::memory:?cache=shared", true)
	if err != nil {
		t.Fatalf("Failed to initialize test database: %v", err)
	}
	// Limit to single connection to avoid race conditions in tests
	db.SetMaxOpenConns(1)
	t.Cleanup(func() {
		db.Close()
	})
	return NewSessionStore(db)
}

// createSessionTestUser creates a test user in the database
func createSessionTestUser(t *testing.T, store *SessionStore, did, handle string) {
	t.Helper()
	_, err := store.db.Exec(`
		INSERT OR IGNORE INTO users (did, handle, pds_endpoint, last_seen)
		VALUES (?, ?, ?, datetime('now'))
	`, did, handle, "https://pds.example.com")
	if err != nil {
		t.Fatalf("Failed to create test user: %v", err)
	}
}

func TestSession_Struct(t *testing.T) {
	sess := &Session{
		ID:             "test-session",
		DID:            "did:plc:test",
		Handle:         "alice.bsky.social",
		PDSEndpoint:    "https://bsky.social",
		OAuthSessionID: "oauth-123",
		ExpiresAt:      time.Now().Add(1 * time.Hour),
	}

	if sess.DID != "did:plc:test" {
		t.Errorf("Expected DID, got %q", sess.DID)
	}
}

// TestSessionStore_Create tests session creation without OAuth
func TestSessionStore_Create(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	sessionID, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	if sessionID == "" {
		t.Error("Create() returned empty session ID")
	}

	// Verify session can be retrieved
	sess, found := store.Get(sessionID)
	if !found {
		t.Error("Created session not found")
	}
	if sess == nil {
		t.Fatal("Session is nil")
	}
	if sess.DID != "did:plc:alice123" {
		t.Errorf("DID = %v, want did:plc:alice123", sess.DID)
	}
	if sess.Handle != "alice.bsky.social" {
		t.Errorf("Handle = %v, want alice.bsky.social", sess.Handle)
	}
	if sess.OAuthSessionID != "" {
		t.Errorf("OAuthSessionID should be empty, got %v", sess.OAuthSessionID)
	}
}

// TestSessionStore_CreateWithOAuth tests session creation with OAuth
func TestSessionStore_CreateWithOAuth(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	oauthSessionID := "oauth-123"
	sessionID, err := store.CreateWithOAuth("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", oauthSessionID, 1*time.Hour)
	if err != nil {
		t.Fatalf("CreateWithOAuth() error = %v", err)
	}

	if sessionID == "" {
		t.Error("CreateWithOAuth() returned empty session ID")
	}

	// Verify session has OAuth session ID
	sess, found := store.Get(sessionID)
	if !found {
		t.Error("Created session not found")
	}
	if sess.OAuthSessionID != oauthSessionID {
		t.Errorf("OAuthSessionID = %v, want %v", sess.OAuthSessionID, oauthSessionID)
	}
}

// TestSessionStore_Get tests retrieving sessions
func TestSessionStore_Get(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	// Create a valid session
	validID, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	// Create a session and manually expire it
	expiredID, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	// Manually update expiration to the past
	_, err = store.db.Exec(`
		UPDATE ui_sessions
		SET expires_at = datetime('now', '-1 hour')
		WHERE id = ?
	`, expiredID)
	if err != nil {
		t.Fatalf("Failed to update expiration: %v", err)
	}

	tests := []struct {
		name      string
		sessionID string
		wantFound bool
	}{
		{
			name:      "valid session",
			sessionID: validID,
			wantFound: true,
		},
		{
			name:      "expired session",
			sessionID: expiredID,
			wantFound: false,
		},
		{
			name:      "non-existent session",
			sessionID: "non-existent-id",
			wantFound: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			sess, found := store.Get(tt.sessionID)
			if found != tt.wantFound {
				t.Errorf("Get() found = %v, want %v", found, tt.wantFound)
			}
			if tt.wantFound && sess == nil {
				t.Error("Expected session, got nil")
			}
		})
	}
}

// TestSessionStore_Extend tests extending session expiration
func TestSessionStore_Extend(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	sessionID, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	// Get initial expiration
	sess1, _ := store.Get(sessionID)
	initialExpiry := sess1.ExpiresAt

	// Wait a bit to ensure time difference
	time.Sleep(10 * time.Millisecond)

	// Extend session
	err = store.Extend(sessionID, 2*time.Hour)
	if err != nil {
		t.Errorf("Extend() error = %v", err)
	}

	// Verify expiration was updated
	sess2, found := store.Get(sessionID)
	if !found {
		t.Fatal("Session not found after extend")
	}
	if !sess2.ExpiresAt.After(initialExpiry) {
		t.Error("ExpiresAt should be later after extend")
	}

	// Test extending non-existent session
	err = store.Extend("non-existent-id", 1*time.Hour)
	if err == nil {
		t.Error("Expected error when extending non-existent session")
	}
	if err != nil && !strings.Contains(err.Error(), "not found") {
		t.Errorf("Expected 'not found' error, got %v", err)
	}
}

// TestSessionStore_Delete tests deleting a session
func TestSessionStore_Delete(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	sessionID, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	// Verify session exists
	_, found := store.Get(sessionID)
	if !found {
		t.Fatal("Session should exist before delete")
	}

	// Delete session
	store.Delete(sessionID)

	// Verify session is gone
	_, found = store.Get(sessionID)
	if found {
		t.Error("Session should not exist after delete")
	}

	// Deleting non-existent session should not error
	store.Delete("non-existent-id")
}

// TestSessionStore_DeleteByDID tests deleting all sessions for a DID
func TestSessionStore_DeleteByDID(t *testing.T) {
	store := setupSessionTestDB(t)
	did := "did:plc:alice123"
	createSessionTestUser(t, store, did, "alice.bsky.social")
	createSessionTestUser(t, store, "did:plc:bob123", "bob.bsky.social")

	// Create multiple sessions for alice
	sessionIDs := make([]string, 3)
	for i := 0; i < 3; i++ {
		id, err := store.Create(did, "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
		if err != nil {
			t.Fatalf("Create() error = %v", err)
		}
		sessionIDs[i] = id
	}

	// Create a session for bob
	bobSessionID, err := store.Create("did:plc:bob123", "bob.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	// Delete all sessions for alice
	store.DeleteByDID(did)

	// Verify alice's sessions are gone
	for _, id := range sessionIDs {
		_, found := store.Get(id)
		if found {
			t.Errorf("Session %v should have been deleted", id)
		}
	}

	// Verify bob's session still exists
	_, found := store.Get(bobSessionID)
	if !found {
		t.Error("Bob's session should still exist")
	}

	// Deleting sessions for non-existent DID should not error
	store.DeleteByDID("did:plc:nonexistent")
}

// TestSessionStore_Cleanup tests removing expired sessions
func TestSessionStore_Cleanup(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	// Create valid session by inserting directly with SQLite datetime format
	validID := "valid-session-id"
	_, err := store.db.Exec(`
		INSERT INTO ui_sessions (id, did, handle, pds_endpoint, oauth_session_id, expires_at, created_at)
		VALUES (?, ?, ?, ?, ?, datetime('now', '+1 hour'), datetime('now'))
	`, validID, "did:plc:alice123", "alice.bsky.social", "https://pds.example.com", "")
	if err != nil {
		t.Fatalf("Failed to create valid session: %v", err)
	}

	// Create expired session
	expiredID := "expired-session-id"
	_, err = store.db.Exec(`
		INSERT INTO ui_sessions (id, did, handle, pds_endpoint, oauth_session_id, expires_at, created_at)
		VALUES (?, ?, ?, ?, ?, datetime('now', '-1 hour'), datetime('now'))
	`, expiredID, "did:plc:alice123", "alice.bsky.social", "https://pds.example.com", "")
	if err != nil {
		t.Fatalf("Failed to create expired session: %v", err)
	}

	// Verify we have 2 sessions before cleanup
	var countBefore int
	err = store.db.QueryRow("SELECT COUNT(*) FROM ui_sessions").Scan(&countBefore)
	if err != nil {
		t.Fatalf("Query error: %v", err)
	}
	if countBefore != 2 {
		t.Fatalf("Expected 2 sessions before cleanup, got %d", countBefore)
	}

	// Run cleanup
	store.Cleanup()

	// Verify valid session still exists in database
	var countValid int
	err = store.db.QueryRow("SELECT COUNT(*) FROM ui_sessions WHERE id = ?", validID).Scan(&countValid)
	if err != nil {
		t.Fatalf("Query error: %v", err)
	}
	if countValid != 1 {
		t.Errorf("Valid session should still exist in database, count = %d", countValid)
	}

	// Verify expired session was cleaned up
	var countExpired int
	err = store.db.QueryRow("SELECT COUNT(*) FROM ui_sessions WHERE id = ?", expiredID).Scan(&countExpired)
	if err != nil {
		t.Fatalf("Query error: %v", err)
	}
	if countExpired != 0 {
		t.Error("Expired session should have been deleted from database")
	}

	// Verify we can still get the valid session
	_, found := store.Get(validID)
	if !found {
		t.Error("Valid session should be retrievable after cleanup")
	}
}

// TestSessionStore_CleanupContext tests context-aware cleanup
func TestSessionStore_CleanupContext(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	// Create a session and manually expire it
	expiredID, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
	if err != nil {
		t.Fatalf("Create() error = %v", err)
	}

	// Manually update expiration to the past
	_, err = store.db.Exec(`
		UPDATE ui_sessions
		SET expires_at = datetime('now', '-1 hour')
		WHERE id = ?
	`, expiredID)
	if err != nil {
		t.Fatalf("Failed to update expiration: %v", err)
	}

	// Run context-aware cleanup
	ctx := context.Background()
	err = store.CleanupContext(ctx)
	if err != nil {
		t.Errorf("CleanupContext() error = %v", err)
	}

	// Verify expired session was cleaned up
	var count int
	err = store.db.QueryRow("SELECT COUNT(*) FROM ui_sessions WHERE id = ?", expiredID).Scan(&count)
	if err != nil {
		t.Fatalf("Query error: %v", err)
	}
	if count != 0 {
		t.Error("Expired session should have been deleted from database")
	}
}

// TestSetCookie tests setting session cookie
func TestSetCookie(t *testing.T) {
	w := httptest.NewRecorder()
	sessionID := "test-session-id"
	maxAge := 3600

	SetCookie(w, sessionID, maxAge)

	cookies := w.Result().Cookies()
	if len(cookies) != 1 {
		t.Fatalf("Expected 1 cookie, got %d", len(cookies))
	}

	cookie := cookies[0]
	if cookie.Name != "atcr_session" {
		t.Errorf("Name = %v, want atcr_session", cookie.Name)
	}
	if cookie.Value != sessionID {
		t.Errorf("Value = %v, want %v", cookie.Value, sessionID)
	}
	if cookie.MaxAge != maxAge {
		t.Errorf("MaxAge = %v, want %v", cookie.MaxAge, maxAge)
	}
	if !cookie.HttpOnly {
		t.Error("HttpOnly should be true")
	}
	if !cookie.Secure {
		t.Error("Secure should be true")
	}
	if cookie.SameSite != http.SameSiteLaxMode {
		t.Errorf("SameSite = %v, want Lax", cookie.SameSite)
	}
	if cookie.Path != "/" {
		t.Errorf("Path = %v, want /", cookie.Path)
	}
}

// TestClearCookie tests clearing session cookie
func TestClearCookie(t *testing.T) {
	w := httptest.NewRecorder()

	ClearCookie(w)

	cookies := w.Result().Cookies()
	if len(cookies) != 1 {
		t.Fatalf("Expected 1 cookie, got %d", len(cookies))
	}

	cookie := cookies[0]
	if cookie.Name != "atcr_session" {
		t.Errorf("Name = %v, want atcr_session", cookie.Name)
	}
	if cookie.Value != "" {
		t.Errorf("Value should be empty, got %v", cookie.Value)
	}
	if cookie.MaxAge != -1 {
		t.Errorf("MaxAge = %v, want -1", cookie.MaxAge)
	}
	if !cookie.HttpOnly {
		t.Error("HttpOnly should be true")
	}
	if !cookie.Secure {
		t.Error("Secure should be true")
	}
}

// TestGetSessionID tests retrieving session ID from cookie
func TestGetSessionID(t *testing.T) {
	tests := []struct {
		name      string
		cookie    *http.Cookie
		wantID    string
		wantFound bool
	}{
		{
			name: "valid cookie",
			cookie: &http.Cookie{
				Name:  "atcr_session",
				Value: "test-session-id",
			},
			wantID:    "test-session-id",
			wantFound: true,
		},
		{
			name:      "no cookie",
			cookie:    nil,
			wantID:    "",
			wantFound: false,
		},
		{
			name: "wrong cookie name",
			cookie: &http.Cookie{
				Name:  "other_cookie",
				Value: "test-value",
			},
			wantID:    "",
			wantFound: false,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := httptest.NewRequest("GET", "/", nil)
			if tt.cookie != nil {
				req.AddCookie(tt.cookie)
			}

			id, found := GetSessionID(req)
			if found != tt.wantFound {
				t.Errorf("GetSessionID() found = %v, want %v", found, tt.wantFound)
			}
			if id != tt.wantID {
				t.Errorf("GetSessionID() id = %v, want %v", id, tt.wantID)
			}
		})
	}
}

// TestSessionStore_SessionIDUniqueness tests that generated session IDs are unique
func TestSessionStore_SessionIDUniqueness(t *testing.T) {
	store := setupSessionTestDB(t)
	createSessionTestUser(t, store, "did:plc:alice123", "alice.bsky.social")

	// Generate multiple session IDs
	ids := make(map[string]bool)
	for i := 0; i < 100; i++ {
		id, err := store.Create("did:plc:alice123", "alice.bsky.social", "https://pds.example.com", 1*time.Hour)
		if err != nil {
			t.Fatalf("Create() error = %v", err)
		}
		if ids[id] {
			t.Errorf("Duplicate session ID generated: %v", id)
		}
		ids[id] = true
	}

	if len(ids) != 100 {
		t.Errorf("Expected 100 unique IDs, got %d", len(ids))
	}
}