relspecgo/pkg/writers/pgsql/writer_test.go

package pgsql

import (
	"bytes"
	"strings"
	"testing"

	"git.warky.dev/wdevs/relspecgo/pkg/models"
	"git.warky.dev/wdevs/relspecgo/pkg/writers"
)

func TestWriteDatabase(t *testing.T) {
	// Create a test database
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create a test table
	table := models.InitTable("users", "public")
	table.Description = "User accounts table"

	// Add columns
	idCol := models.InitColumn("id", "users", "public")
	idCol.Type = "integer"
	idCol.Description = "Primary key"
	idCol.Default = "nextval('public.identity_users_id'::regclass)"
	table.Columns["id"] = idCol

	nameCol := models.InitColumn("name", "users", "public")
	nameCol.Type = "text"
	nameCol.Description = "User name"
	table.Columns["name"] = nameCol

	emailCol := models.InitColumn("email", "users", "public")
	emailCol.Type = "text"
	emailCol.Description = "Email address"
	table.Columns["email"] = emailCol

	// Add primary key constraint
	pkConstraint := &models.Constraint{
		Name:    "pk_users",
		Type:    models.PrimaryKeyConstraint,
		Columns: []string{"id"},
	}
	table.Constraints["pk_users"] = pkConstraint

	// Add unique index
	uniqueEmailIndex := &models.Index{
		Name:    "uidx_users_email",
		Unique:  true,
		Columns: []string{"email"},
	}
	table.Indexes["uidx_users_email"] = uniqueEmailIndex

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the database
	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()

	// Print output for debugging
	t.Logf("Generated SQL:\n%s", output)

	// Verify output contains expected elements
	expectedStrings := []string{
		"CREATE TABLE",
		"PRIMARY KEY",
		"UNIQUE INDEX",
		"COMMENT ON TABLE",
		"COMMENT ON COLUMN",
	}

	for _, expected := range expectedStrings {
		if !strings.Contains(output, expected) {
			t.Errorf("Output missing expected string: %s\nFull output:\n%s", expected, output)
		}
	}
}

func TestWriteForeignKeys(t *testing.T) {
	// Create a test database with two related tables
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create parent table (users)
	usersTable := models.InitTable("users", "public")
	idCol := models.InitColumn("id", "users", "public")
	idCol.Type = "integer"
	usersTable.Columns["id"] = idCol

	// Create child table (posts)
	postsTable := models.InitTable("posts", "public")
	postIdCol := models.InitColumn("id", "posts", "public")
	postIdCol.Type = "integer"
	postsTable.Columns["id"] = postIdCol

	userIdCol := models.InitColumn("user_id", "posts", "public")
	userIdCol.Type = "integer"
	postsTable.Columns["user_id"] = userIdCol

	// Add foreign key constraint
	fkConstraint := &models.Constraint{
		Name:              "fk_posts_users",
		Type:              models.ForeignKeyConstraint,
		Columns:           []string{"user_id"},
		ReferencedTable:   "users",
		ReferencedSchema:  "public",
		ReferencedColumns: []string{"id"},
		OnDelete:          "CASCADE",
		OnUpdate:          "CASCADE",
	}
	postsTable.Constraints["fk_posts_users"] = fkConstraint

	// Add relationship
	relationship := &models.Relationship{
		Name:       "fk_posts_users",
		FromTable:  "posts",
		FromSchema: "public",
		ToTable:    "users",
		ToSchema:   "public",
		ForeignKey: "fk_posts_users",
	}
	postsTable.Relationships["fk_posts_users"] = relationship

	schema.Tables = append(schema.Tables, usersTable, postsTable)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the database
	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()

	// Print output for debugging
	t.Logf("Generated SQL:\n%s", output)

	// Verify foreign key is present
	if !strings.Contains(output, "FOREIGN KEY") {
		t.Errorf("Output missing FOREIGN KEY statement\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "ON DELETE CASCADE") {
		t.Errorf("Output missing ON DELETE CASCADE\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "ON UPDATE CASCADE") {
		t.Errorf("Output missing ON UPDATE CASCADE\nFull output:\n%s", output)
	}
}

func TestWriteUniqueConstraints(t *testing.T) {
	// Create a test database with unique constraints
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create table with unique constraints
	table := models.InitTable("users", "public")

	// Add columns
	emailCol := models.InitColumn("email", "users", "public")
	emailCol.Type = "varchar(255)"
	emailCol.NotNull = true
	table.Columns["email"] = emailCol

	guidCol := models.InitColumn("guid", "users", "public")
	guidCol.Type = "uuid"
	guidCol.NotNull = true
	table.Columns["guid"] = guidCol

	// Add unique constraints
	emailConstraint := &models.Constraint{
		Name:    "uq_email",
		Type:    models.UniqueConstraint,
		Schema:  "public",
		Table:   "users",
		Columns: []string{"email"},
	}
	table.Constraints["uq_email"] = emailConstraint

	guidConstraint := &models.Constraint{
		Name:    "uq_guid",
		Type:    models.UniqueConstraint,
		Schema:  "public",
		Table:   "users",
		Columns: []string{"guid"},
	}
	table.Constraints["uq_guid"] = guidConstraint

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the database
	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()

	// Print output for debugging
	t.Logf("Generated SQL:\n%s", output)

	// Verify unique constraints are present
	if !strings.Contains(output, "-- Unique constraints for schema: public") {
		t.Errorf("Output missing unique constraints header")
	}
	if !strings.Contains(output, "ADD CONSTRAINT uq_email UNIQUE (email)") {
		t.Errorf("Output missing uq_email unique constraint\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "ADD CONSTRAINT uq_guid UNIQUE (guid)") {
		t.Errorf("Output missing uq_guid unique constraint\nFull output:\n%s", output)
	}
}

func TestWriteCheckConstraints(t *testing.T) {
	// Create a test database with check constraints
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create table with check constraints
	table := models.InitTable("products", "public")

	// Add columns
	priceCol := models.InitColumn("price", "products", "public")
	priceCol.Type = "numeric(10,2)"
	table.Columns["price"] = priceCol

	statusCol := models.InitColumn("status", "products", "public")
	statusCol.Type = "varchar(20)"
	table.Columns["status"] = statusCol

	quantityCol := models.InitColumn("quantity", "products", "public")
	quantityCol.Type = "integer"
	table.Columns["quantity"] = quantityCol

	// Add check constraints
	priceConstraint := &models.Constraint{
		Name:       "ck_price_positive",
		Type:       models.CheckConstraint,
		Schema:     "public",
		Table:      "products",
		Expression: "price >= 0",
	}
	table.Constraints["ck_price_positive"] = priceConstraint

	statusConstraint := &models.Constraint{
		Name:       "ck_status_valid",
		Type:       models.CheckConstraint,
		Schema:     "public",
		Table:      "products",
		Expression: "status IN ('active', 'inactive', 'discontinued')",
	}
	table.Constraints["ck_status_valid"] = statusConstraint

	quantityConstraint := &models.Constraint{
		Name:       "ck_quantity_nonnegative",
		Type:       models.CheckConstraint,
		Schema:     "public",
		Table:      "products",
		Expression: "quantity >= 0",
	}
	table.Constraints["ck_quantity_nonnegative"] = quantityConstraint

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the database
	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()

	// Print output for debugging
	t.Logf("Generated SQL:\n%s", output)

	// Verify check constraints are present
	if !strings.Contains(output, "-- Check constraints for schema: public") {
		t.Errorf("Output missing check constraints header")
	}
	if !strings.Contains(output, "ADD CONSTRAINT ck_price_positive CHECK (price >= 0)") {
		t.Errorf("Output missing ck_price_positive check constraint\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "ADD CONSTRAINT ck_status_valid CHECK (status IN ('active', 'inactive', 'discontinued'))") {
		t.Errorf("Output missing ck_status_valid check constraint\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "ADD CONSTRAINT ck_quantity_nonnegative CHECK (quantity >= 0)") {
		t.Errorf("Output missing ck_quantity_nonnegative check constraint\nFull output:\n%s", output)
	}
}

func TestWriteAllConstraintTypes(t *testing.T) {
	// Create a comprehensive test with all constraint types
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create orders table
	ordersTable := models.InitTable("orders", "public")

	// Add columns
	idCol := models.InitColumn("id", "orders", "public")
	idCol.Type = "integer"
	idCol.IsPrimaryKey = true
	ordersTable.Columns["id"] = idCol

	userIDCol := models.InitColumn("user_id", "orders", "public")
	userIDCol.Type = "integer"
	userIDCol.NotNull = true
	ordersTable.Columns["user_id"] = userIDCol

	orderNumberCol := models.InitColumn("order_number", "orders", "public")
	orderNumberCol.Type = "varchar(50)"
	orderNumberCol.NotNull = true
	ordersTable.Columns["order_number"] = orderNumberCol

	totalCol := models.InitColumn("total", "orders", "public")
	totalCol.Type = "numeric(10,2)"
	ordersTable.Columns["total"] = totalCol

	statusCol := models.InitColumn("status", "orders", "public")
	statusCol.Type = "varchar(20)"
	ordersTable.Columns["status"] = statusCol

	// Add primary key constraint
	pkConstraint := &models.Constraint{
		Name:    "pk_orders",
		Type:    models.PrimaryKeyConstraint,
		Schema:  "public",
		Table:   "orders",
		Columns: []string{"id"},
	}
	ordersTable.Constraints["pk_orders"] = pkConstraint

	// Add unique constraint
	uniqueConstraint := &models.Constraint{
		Name:    "uq_order_number",
		Type:    models.UniqueConstraint,
		Schema:  "public",
		Table:   "orders",
		Columns: []string{"order_number"},
	}
	ordersTable.Constraints["uq_order_number"] = uniqueConstraint

	// Add check constraint
	checkConstraint := &models.Constraint{
		Name:       "ck_total_positive",
		Type:       models.CheckConstraint,
		Schema:     "public",
		Table:      "orders",
		Expression: "total > 0",
	}
	ordersTable.Constraints["ck_total_positive"] = checkConstraint

	statusCheckConstraint := &models.Constraint{
		Name:       "ck_status_valid",
		Type:       models.CheckConstraint,
		Schema:     "public",
		Table:      "orders",
		Expression: "status IN ('pending', 'completed', 'cancelled')",
	}
	ordersTable.Constraints["ck_status_valid"] = statusCheckConstraint

	// Add foreign key constraint (referencing a users table)
	fkConstraint := &models.Constraint{
		Name:              "fk_orders_user",
		Type:              models.ForeignKeyConstraint,
		Schema:            "public",
		Table:             "orders",
		Columns:           []string{"user_id"},
		ReferencedSchema:  "public",
		ReferencedTable:   "users",
		ReferencedColumns: []string{"id"},
		OnDelete:          "CASCADE",
		OnUpdate:          "CASCADE",
	}
	ordersTable.Constraints["fk_orders_user"] = fkConstraint

	schema.Tables = append(schema.Tables, ordersTable)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the database
	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()

	// Print output for debugging
	t.Logf("Generated SQL:\n%s", output)

	// Verify all constraint types are present
	expectedConstraints := map[string]string{
		"Primary Key":      "PRIMARY KEY",
		"Unique":           "ADD CONSTRAINT uq_order_number UNIQUE (order_number)",
		"Check (total)":    "ADD CONSTRAINT ck_total_positive CHECK (total > 0)",
		"Check (status)":   "ADD CONSTRAINT ck_status_valid CHECK (status IN ('pending', 'completed', 'cancelled'))",
		"Foreign Key":      "FOREIGN KEY",
	}

	for name, expected := range expectedConstraints {
		if !strings.Contains(output, expected) {
			t.Errorf("Output missing %s constraint: %s\nFull output:\n%s", name, expected, output)
		}
	}

	// Verify section headers
	sections := []string{
		"-- Primary keys for schema: public",
		"-- Unique constraints for schema: public",
		"-- Check constraints for schema: public",
		"-- Foreign keys for schema: public",
	}

	for _, section := range sections {
		if !strings.Contains(output, section) {
			t.Errorf("Output missing section header: %s", section)
		}
	}
}

func TestWriteTable(t *testing.T) {
	// Create a single table
	table := models.InitTable("products", "public")

	idCol := models.InitColumn("id", "products", "public")
	idCol.Type = "integer"
	table.Columns["id"] = idCol

	nameCol := models.InitColumn("name", "products", "public")
	nameCol.Type = "text"
	table.Columns["name"] = nameCol

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the table
	err := writer.WriteTable(table)
	if err != nil {
		t.Fatalf("WriteTable failed: %v", err)
	}

	output := buf.String()

	// Verify output contains table creation
	if !strings.Contains(output, "CREATE TABLE") {
		t.Error("Output missing CREATE TABLE statement")
	}
	if !strings.Contains(output, "products") {
		t.Error("Output missing table name 'products'")
	}
}

func TestEscapeQuote(t *testing.T) {
	tests := []struct {
		input    string
		expected string
	}{
		{"simple text", "simple text"},
		{"text with 'quote'", "text with ''quote''"},
		{"multiple 'quotes' here", "multiple ''quotes'' here"},
		{"", ""},
	}

	for _, tt := range tests {
		result := escapeQuote(tt.input)
		if result != tt.expected {
			t.Errorf("escapeQuote(%q) = %q, want %q", tt.input, result, tt.expected)
		}
	}
}

func TestIsIntegerType(t *testing.T) {
	tests := []struct {
		input    string
		expected bool
	}{
		{"integer", true},
		{"INTEGER", true},
		{"bigint", true},
		{"smallint", true},
		{"serial", true},
		{"bigserial", true},
		{"text", false},
		{"varchar", false},
		{"uuid", false},
	}

	for _, tt := range tests {
		result := isIntegerType(tt.input)
		if result != tt.expected {
			t.Errorf("isIntegerType(%q) = %v, want %v", tt.input, result, tt.expected)
		}
	}
}

func TestTypeConversion(t *testing.T) {
	// Test that invalid Go types are converted to valid PostgreSQL types
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create a test table with Go types instead of SQL types
	table := models.InitTable("test_types", "public")

	// Add columns with Go types (invalid for PostgreSQL)
	stringCol := models.InitColumn("name", "test_types", "public")
	stringCol.Type = "string" // Should be converted to "text"
	table.Columns["name"] = stringCol

	int64Col := models.InitColumn("big_id", "test_types", "public")
	int64Col.Type = "int64" // Should be converted to "bigint"
	table.Columns["big_id"] = int64Col

	int16Col := models.InitColumn("small_id", "test_types", "public")
	int16Col.Type = "int16" // Should be converted to "smallint"
	table.Columns["small_id"] = int16Col

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write the database
	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()

	// Print output for debugging
	t.Logf("Generated SQL:\n%s", output)

	// Verify that Go types were converted to PostgreSQL types
	if strings.Contains(output, "string") {
		t.Errorf("Output contains 'string' type - should be converted to 'text'\nFull output:\n%s", output)
	}
	if strings.Contains(output, "int64") {
		t.Errorf("Output contains 'int64' type - should be converted to 'bigint'\nFull output:\n%s", output)
	}
	if strings.Contains(output, "int16") {
		t.Errorf("Output contains 'int16' type - should be converted to 'smallint'\nFull output:\n%s", output)
	}

	// Verify correct PostgreSQL types are present
	if !strings.Contains(output, "text") {
		t.Errorf("Output missing 'text' type (converted from 'string')\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "bigint") {
		t.Errorf("Output missing 'bigint' type (converted from 'int64')\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "smallint") {
		t.Errorf("Output missing 'smallint' type (converted from 'int16')\nFull output:\n%s", output)
	}
}

func TestPrimaryKeyExistenceCheck(t *testing.T) {
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")
	table := models.InitTable("products", "public")

	idCol := models.InitColumn("id", "products", "public")
	idCol.Type = "integer"
	idCol.IsPrimaryKey = true
	table.Columns["id"] = idCol

	nameCol := models.InitColumn("name", "products", "public")
	nameCol.Type = "text"
	table.Columns["name"] = nameCol

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()
	t.Logf("Generated SQL:\n%s", output)

	// Verify our naming convention is used
	if !strings.Contains(output, "pk_public_products") {
		t.Errorf("Output missing expected primary key name 'pk_public_products'\nFull output:\n%s", output)
	}

	// Verify it drops auto-generated primary keys
	if !strings.Contains(output, "products_pkey") || !strings.Contains(output, "DROP CONSTRAINT") {
		t.Errorf("Output missing logic to drop auto-generated primary key\nFull output:\n%s", output)
	}

	// Verify it checks for our specific named constraint before adding it
	if !strings.Contains(output, "constraint_name = 'pk_public_products'") {
		t.Errorf("Output missing check for our named primary key constraint\nFull output:\n%s", output)
	}
}

func TestColumnSizeSpecifiers(t *testing.T) {
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")
	table := models.InitTable("test_sizes", "public")

	// Integer with invalid size specifier - should ignore size
	integerCol := models.InitColumn("int_col", "test_sizes", "public")
	integerCol.Type = "integer"
	integerCol.Length = 32
	table.Columns["int_col"] = integerCol

	// Bigint with invalid size specifier - should ignore size
	bigintCol := models.InitColumn("bigint_col", "test_sizes", "public")
	bigintCol.Type = "bigint"
	bigintCol.Length = 64
	table.Columns["bigint_col"] = bigintCol

	// Smallint with invalid size specifier - should ignore size
	smallintCol := models.InitColumn("smallint_col", "test_sizes", "public")
	smallintCol.Type = "smallint"
	smallintCol.Length = 16
	table.Columns["smallint_col"] = smallintCol

	// Text with length - should convert to varchar
	textCol := models.InitColumn("text_col", "test_sizes", "public")
	textCol.Type = "text"
	textCol.Length = 100
	table.Columns["text_col"] = textCol

	// Varchar with length - should keep varchar with length
	varcharCol := models.InitColumn("varchar_col", "test_sizes", "public")
	varcharCol.Type = "varchar"
	varcharCol.Length = 50
	table.Columns["varchar_col"] = varcharCol

	// Decimal with precision and scale - should keep them
	decimalCol := models.InitColumn("decimal_col", "test_sizes", "public")
	decimalCol.Type = "decimal"
	decimalCol.Precision = 19
	decimalCol.Scale = 4
	table.Columns["decimal_col"] = decimalCol

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	err := writer.WriteDatabase(db)
	if err != nil {
		t.Fatalf("WriteDatabase failed: %v", err)
	}

	output := buf.String()
	t.Logf("Generated SQL:\n%s", output)

	// Verify invalid size specifiers are NOT present
	invalidPatterns := []string{
		"integer(32)",
		"bigint(64)",
		"smallint(16)",
		"text(100)",
	}
	for _, pattern := range invalidPatterns {
		if strings.Contains(output, pattern) {
			t.Errorf("Output contains invalid pattern '%s' - PostgreSQL doesn't support this\nFull output:\n%s", pattern, output)
		}
	}

	// Verify valid patterns ARE present
	validPatterns := []string{
		"integer",     // without size
		"bigint",      // without size
		"smallint",    // without size
		"varchar(100)", // text converted to varchar with length
		"varchar(50)",  // varchar with length
		"decimal(19,4)", // decimal with precision and scale
	}
	for _, pattern := range validPatterns {
		if !strings.Contains(output, pattern) {
			t.Errorf("Output missing expected pattern '%s'\nFull output:\n%s", pattern, output)
		}
	}
}

func TestGenerateAddColumnStatements(t *testing.T) {
	// Create a test database with tables that have new columns
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create a table with columns
	table := models.InitTable("users", "public")

	// Existing column
	idCol := models.InitColumn("id", "users", "public")
	idCol.Type = "integer"
	idCol.NotNull = true
	idCol.Sequence = 1
	table.Columns["id"] = idCol

	// New column to be added
	emailCol := models.InitColumn("email", "users", "public")
	emailCol.Type = "varchar"
	emailCol.Length = 255
	emailCol.NotNull = true
	emailCol.Sequence = 2
	table.Columns["email"] = emailCol

	// New column with default
	statusCol := models.InitColumn("status", "users", "public")
	statusCol.Type = "text"
	statusCol.Default = "active"
	statusCol.Sequence = 3
	table.Columns["status"] = statusCol

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	// Create writer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)

	// Generate ADD COLUMN statements
	statements, err := writer.GenerateAddColumnsForDatabase(db)
	if err != nil {
		t.Fatalf("GenerateAddColumnsForDatabase failed: %v", err)
	}

	// Join all statements to verify content
	output := strings.Join(statements, "\n")
	t.Logf("Generated ADD COLUMN statements:\n%s", output)

	// Verify expected elements
	expectedStrings := []string{
		"ALTER TABLE public.users ADD COLUMN id integer NOT NULL",
		"ALTER TABLE public.users ADD COLUMN email varchar(255) NOT NULL",
		"ALTER TABLE public.users ADD COLUMN status text DEFAULT 'active'",
		"information_schema.columns",
		"table_schema = 'public'",
		"table_name = 'users'",
		"column_name = 'id'",
		"column_name = 'email'",
		"column_name = 'status'",
	}

	for _, expected := range expectedStrings {
		if !strings.Contains(output, expected) {
			t.Errorf("Output missing expected string: %s\nFull output:\n%s", expected, output)
		}
	}

	// Verify DO blocks are present for conditional adds
	doBlockCount := strings.Count(output, "DO $$")
	if doBlockCount < 3 {
		t.Errorf("Expected at least 3 DO blocks (one per column), got %d", doBlockCount)
	}

	// Verify IF NOT EXISTS logic
	ifNotExistsCount := strings.Count(output, "IF NOT EXISTS")
	if ifNotExistsCount < 3 {
		t.Errorf("Expected at least 3 IF NOT EXISTS checks (one per column), got %d", ifNotExistsCount)
	}
}

func TestWriteAddColumnStatements(t *testing.T) {
	// Create a test database
	db := models.InitDatabase("testdb")
	schema := models.InitSchema("public")

	// Create a table with a new column to be added
	table := models.InitTable("products", "public")

	idCol := models.InitColumn("id", "products", "public")
	idCol.Type = "integer"
	table.Columns["id"] = idCol

	// New column with various properties
	descCol := models.InitColumn("description", "products", "public")
	descCol.Type = "text"
	descCol.NotNull = false
	table.Columns["description"] = descCol

	schema.Tables = append(schema.Tables, table)
	db.Schemas = append(db.Schemas, schema)

	// Create writer with output to buffer
	var buf bytes.Buffer
	options := &writers.WriterOptions{}
	writer := NewWriter(options)
	writer.writer = &buf

	// Write ADD COLUMN statements
	err := writer.WriteAddColumnStatements(db)
	if err != nil {
		t.Fatalf("WriteAddColumnStatements failed: %v", err)
	}

	output := buf.String()
	t.Logf("Generated output:\n%s", output)

	// Verify output contains expected elements
	if !strings.Contains(output, "ALTER TABLE public.products ADD COLUMN id integer") {
		t.Errorf("Output missing ADD COLUMN for id\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "ALTER TABLE public.products ADD COLUMN description text") {
		t.Errorf("Output missing ADD COLUMN for description\nFull output:\n%s", output)
	}
	if !strings.Contains(output, "DO $$") {
		t.Errorf("Output missing DO block\nFull output:\n%s", output)
	}
}