package notes

import (
	"testing"
	"time"

	"github.com/glebarez/sqlite"
	"github.com/google/uuid"
	"gorm.io/gorm"
)

func setupTestDB(t *testing.T) *gorm.DB {
	db, err := gorm.Open(sqlite.Open(":memory:"), &gorm.Config{
		SkipDefaultTransaction: true,
	})
	if err != nil {
		t.Fatalf("Failed to open test database: %v", err)
	}

	if err := db.AutoMigrate(&Note{}, &NoteLink{}); err != nil {
		t.Fatalf("Failed to migrate test database: %v", err)
	}

	return db
}

func createTestNote(t *testing.T, db *gorm.DB, title, content string) *Note {
	note := &Note{
		ID:        uuid.New().String(),
		Title:     title,
		Content:   content,
		CreatedAt: time.Now(),
		UpdatedAt: time.Now(),
	}

	if err := db.Create(note).Error; err != nil {
		t.Fatalf("Failed to create test note: %v", err)
	}

	return note
}

func TestExtractLinks(t *testing.T) {
	tests := []struct {
		name     string
		content  string
		expected []string
	}{
		{
			name:     "no links",
			content:  "Just some text without links",
			expected: []string{},
		},
		{
			name:     "single link",
			content:  "Text with [[another note]] link",
			expected: []string{"another note"},
		},
		{
			name:     "multiple links",
			content:  "Text with [[first]] and [[second]] links",
			expected: []string{"first", "second"},
		},
		{
			name:     "repeated links",
			content:  "[[same]] link [[same]] twice",
			expected: []string{"same", "same"},
		},
	}

	note := &Note{}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := note.ExtractLinks(tt.content)
			if len(got) != len(tt.expected) {
				t.Errorf("ExtractLinks() got %v links, want %v", len(got), len(tt.expected))
			}
			for i, link := range got {
				if link != tt.expected[i] {
					t.Errorf("ExtractLinks() got %v, want %v", link, tt.expected[i])
				}
			}
		})
	}
}

func TestUpdateLinks(t *testing.T) {
	db := setupTestDB(t)

	// Create some test notes
	note1 := createTestNote(t, db, "First Note", "Content with [[Second Note]] and [[Third Note]]")
	note2 := createTestNote(t, db, "Second Note", "Some content")
	createTestNote(t, db, "Third Note", "More content") // Create but don't need to track

	// Test creating links
	t.Run("create links", func(t *testing.T) {
		if err := note1.UpdateLinks(db); err != nil {
			t.Fatalf("UpdateLinks() error = %v", err)
		}

		// Verify links were created
		var links []NoteLink
		if err := db.Find(&links).Error; err != nil {
			t.Fatalf("Failed to query links: %v", err)
		}

		if len(links) != 2 {
			t.Errorf("Expected 2 links, got %d", len(links))
		}

		// Load note with relationships
		var loadedNote Note
		if err := db.Preload("LinksTo").First(&loadedNote, "id = ?", note1.ID).Error; err != nil {
			t.Fatalf("Failed to load note: %v", err)
		}

		if len(loadedNote.LinksTo) != 2 {
			t.Errorf("Expected 2 LinksTo relationships, got %d", len(loadedNote.LinksTo))
		}
	})

	// Test updating links
	t.Run("update links", func(t *testing.T) {
		note1.Content = "Content with [[Second Note]] only" // Remove Third Note link
		if err := note1.UpdateLinks(db); err != nil {
			t.Fatalf("UpdateLinks() error = %v", err)
		}

		// Verify links were updated
		var links []NoteLink
		if err := db.Find(&links).Error; err != nil {
			t.Fatalf("Failed to query links: %v", err)
		}

		if len(links) != 1 {
			t.Errorf("Expected 1 link, got %d", len(links))
		}

		// Load note with relationships
		var loadedNote Note
		if err := db.Preload("LinksTo").First(&loadedNote, "id = ?", note1.ID).Error; err != nil {
			t.Fatalf("Failed to load note: %v", err)
		}

		if len(loadedNote.LinksTo) != 1 {
			t.Errorf("Expected 1 LinksTo relationship, got %d", len(loadedNote.LinksTo))
		}
	})

	// Test bidirectional relationships
	t.Run("bidirectional relationships", func(t *testing.T) {
		// Add a link back to First Note
		note2.Content = "Content with [[First Note]]"
		if err := note2.UpdateLinks(db); err != nil {
			t.Fatalf("UpdateLinks() error = %v", err)
		}

		// Check First Note's LinkedBy
		var note1Updated Note
		if err := db.Preload("LinkedBy").First(&note1Updated, "id = ?", note1.ID).Error; err != nil {
			t.Fatalf("Failed to load note: %v", err)
		}

		if len(note1Updated.LinkedBy) != 1 {
			t.Errorf("Expected 1 LinkedBy relationship, got %d", len(note1Updated.LinkedBy))
		}
	})

	// Test non-existent links
	t.Run("non-existent links", func(t *testing.T) {
		note1.Content = "Content with [[Non-existent Note]]"
		if err := note1.UpdateLinks(db); err != nil {
			t.Fatalf("UpdateLinks() error = %v", err)
		}

		// Verify no links were created
		var links []NoteLink
		if err := db.Find(&links).Error; err != nil {
			t.Fatalf("Failed to query links: %v", err)
		}

		if len(links) != 1 { // Should still have the link from Second Note to First Note
			t.Errorf("Expected 1 link, got %d", len(links))
		}
	})
}