package integration

import (
	"os"
	"path/filepath"
	"testing"

	"git.warky.dev/wdevs/relspecgo/pkg/models"
	"git.warky.dev/wdevs/relspecgo/pkg/readers"
	bunreader "git.warky.dev/wdevs/relspecgo/pkg/readers/bun"
	gormreader "git.warky.dev/wdevs/relspecgo/pkg/readers/gorm"
	yamlreader "git.warky.dev/wdevs/relspecgo/pkg/readers/yaml"
	"git.warky.dev/wdevs/relspecgo/pkg/writers"
	bunwriter "git.warky.dev/wdevs/relspecgo/pkg/writers/bun"
	gormwriter "git.warky.dev/wdevs/relspecgo/pkg/writers/gorm"
	yamlwriter "git.warky.dev/wdevs/relspecgo/pkg/writers/yaml"
	"github.com/stretchr/testify/require"
	"gopkg.in/yaml.v3"
)

// ComparisonResults holds the results of database comparison
type ComparisonResults struct {
	Schemas              int
	Tables               int
	Columns              int
	OriginalIndexes      int
	RoundtripIndexes     int
	OriginalConstraints  int
	RoundtripConstraints int
}

// countDatabaseStats counts tables, indexes, and constraints in a database
func countDatabaseStats(db *models.Database) (tables, indexes, constraints int) {
	for _, schema := range db.Schemas {
		tables += len(schema.Tables)
		for _, table := range schema.Tables {
			indexes += len(table.Indexes)
			constraints += len(table.Constraints)
		}
	}
	return
}

// compareDatabases performs comprehensive comparison between two databases
func compareDatabases(t *testing.T, db1, db2 *models.Database, ormName string) ComparisonResults {
	t.Helper()

	results := ComparisonResults{}

	// Compare high-level structure
	t.Log("  Comparing high-level structure...")
	require.Equal(t, len(db1.Schemas), len(db2.Schemas), "Schema count should match")
	results.Schemas = len(db1.Schemas)

	// Count totals
	tables1, indexes1, constraints1 := countDatabaseStats(db1)
	_, indexes2, constraints2 := countDatabaseStats(db2)

	results.OriginalIndexes = indexes1
	results.RoundtripIndexes = indexes2
	results.OriginalConstraints = constraints1
	results.RoundtripConstraints = constraints2

	// Compare schemas and tables
	for i, schema1 := range db1.Schemas {
		if i >= len(db2.Schemas) {
			t.Errorf("Schema index %d out of bounds in second database", i)
			continue
		}
		schema2 := db2.Schemas[i]

		require.Equal(t, schema1.Name, schema2.Name, "Schema names should match")
		require.Equal(t, len(schema1.Tables), len(schema2.Tables),
			"Table count in schema '%s' should match", schema1.Name)

		// Compare tables
		for j, table1 := range schema1.Tables {
			if j >= len(schema2.Tables) {
				t.Errorf("Table index %d out of bounds in schema '%s'", j, schema1.Name)
				continue
			}
			table2 := schema2.Tables[j]

			require.Equal(t, table1.Name, table2.Name,
				"Table names should match in schema '%s'", schema1.Name)

			// Compare column count
			require.Equal(t, len(table1.Columns), len(table2.Columns),
				"Column count in table '%s.%s' should match", schema1.Name, table1.Name)

			results.Columns += len(table1.Columns)

			// Compare each column
			for colName, col1 := range table1.Columns {
				col2, ok := table2.Columns[colName]
				if !ok {
					t.Errorf("Column '%s' missing from roundtrip table '%s.%s'",
						colName, schema1.Name, table1.Name)
					continue
				}

				// Compare key column properties
				require.Equal(t, col1.Name, col2.Name,
					"Column name mismatch in '%s.%s.%s'", schema1.Name, table1.Name, colName)
				require.Equal(t, col1.Type, col2.Type,
					"Column type mismatch in '%s.%s.%s'", schema1.Name, table1.Name, colName)
				require.Equal(t, col1.Length, col2.Length,
					"Column length mismatch in '%s.%s.%s'", schema1.Name, table1.Name, colName)
				require.Equal(t, col1.IsPrimaryKey, col2.IsPrimaryKey,
					"Primary key mismatch in '%s.%s.%s'", schema1.Name, table1.Name, colName)
				require.Equal(t, col1.NotNull, col2.NotNull,
					"NotNull mismatch in '%s.%s.%s'", schema1.Name, table1.Name, colName)

				// Log defaults that don't match (these can vary in representation)
				if col1.Default != col2.Default {
					t.Logf("  ℹ Default value differs for '%s.%s.%s': '%v' vs '%v'",
						schema1.Name, table1.Name, colName, col1.Default, col2.Default)
				}
			}

			// Log index and constraint differences (ORM readers may not capture all of these)
			if len(table1.Indexes) != len(table2.Indexes) {
				t.Logf("  ℹ Index count differs for table '%s.%s': %d vs %d",
					schema1.Name, table1.Name, len(table1.Indexes), len(table2.Indexes))
			}
			if len(table1.Constraints) != len(table2.Constraints) {
				t.Logf("  ℹ Constraint count differs for table '%s.%s': %d vs %d",
					schema1.Name, table1.Name, len(table1.Constraints), len(table2.Constraints))
			}
		}
	}

	results.Tables = tables1
	t.Logf("  ✓ Validated %d schemas, %d tables, %d columns", results.Schemas, results.Tables, results.Columns)

	return results
}

// TestYAMLToBunRoundTrip tests YAML → Bun Go → YAML roundtrip
func TestYAMLToBunRoundTrip(t *testing.T) {
	testDir := t.TempDir()

	// Step 1: Read YAML file
	t.Log("Step 1: Reading YAML file...")
	yamlPath := filepath.Join("..", "assets", "yaml", "complex_database.yaml")
	yamlReaderOpts := &readers.ReaderOptions{
		FilePath: yamlPath,
	}
	yamlReader := yamlreader.NewReader(yamlReaderOpts)

	dbFromYAML, err := yamlReader.ReadDatabase()
	require.NoError(t, err, "Failed to read YAML file")
	require.NotNil(t, dbFromYAML, "Database from YAML should not be nil")
	t.Logf("  ✓ Read database '%s' with %d schemas", dbFromYAML.Name, len(dbFromYAML.Schemas))

	// Log initial stats
	totalTables, totalIndexes, totalConstraints := countDatabaseStats(dbFromYAML)
	t.Logf("  ✓ Original: %d tables, %d indexes, %d constraints", totalTables, totalIndexes, totalConstraints)

	// Step 2: Write to Bun Go code
	t.Log("Step 2: Writing to Bun Go code...")
	bunGoPath := filepath.Join(testDir, "models_bun.go")
	bunWriterOpts := &writers.WriterOptions{
		OutputPath:  bunGoPath,
		PackageName: "models",
		Metadata: map[string]interface{}{
			"generate_table_name": true,
			"generate_get_id":     false,
		},
	}
	bunWriter := bunwriter.NewWriter(bunWriterOpts)

	err = bunWriter.WriteDatabase(dbFromYAML)
	require.NoError(t, err, "Failed to write Bun Go code")

	bunStat, err := os.Stat(bunGoPath)
	require.NoError(t, err, "Bun Go file should exist")
	require.Greater(t, bunStat.Size(), int64(0), "Bun Go file should not be empty")
	t.Logf("  ✓ Wrote Bun Go file (%d bytes)", bunStat.Size())

	// Step 3: Read Bun Go code back
	t.Log("Step 3: Reading Bun Go code back...")
	bunReaderOpts := &readers.ReaderOptions{
		FilePath: bunGoPath,
	}
	bunReader := bunreader.NewReader(bunReaderOpts)

	dbFromBun, err := bunReader.ReadDatabase()
	require.NoError(t, err, "Failed to read Bun Go code")
	require.NotNil(t, dbFromBun, "Database from Bun should not be nil")
	t.Logf("  ✓ Read database from Bun with %d schemas", len(dbFromBun.Schemas))

	// Step 4: Write back to YAML
	t.Log("Step 4: Writing back to YAML...")
	yaml2Path := filepath.Join(testDir, "roundtrip.yaml")
	yamlWriter2Opts := &writers.WriterOptions{
		OutputPath: yaml2Path,
	}
	yamlWriter2 := yamlwriter.NewWriter(yamlWriter2Opts)

	err = yamlWriter2.WriteDatabase(dbFromBun)
	require.NoError(t, err, "Failed to write YAML")

	yaml2Stat, err := os.Stat(yaml2Path)
	require.NoError(t, err, "Second YAML file should exist")
	require.Greater(t, yaml2Stat.Size(), int64(0), "Second YAML file should not be empty")
	t.Logf("  ✓ Wrote second YAML file (%d bytes)", yaml2Stat.Size())

	// Step 5: Compare YAML files
	t.Log("Step 5: Comparing YAML outputs...")

	// Read both YAML files
	yaml1Data, err := os.ReadFile(yamlPath)
	require.NoError(t, err, "Failed to read first YAML")

	yaml2Data, err := os.ReadFile(yaml2Path)
	require.NoError(t, err, "Failed to read second YAML")

	// Parse into Database models for comparison
	var db1, db2 models.Database
	err = yaml.Unmarshal(yaml1Data, &db1)
	require.NoError(t, err, "Failed to parse first YAML")

	err = yaml.Unmarshal(yaml2Data, &db2)
	require.NoError(t, err, "Failed to parse second YAML")

	// Comprehensive comparison
	compareResults := compareDatabases(t, &db1, &db2, "Bun")

	// Summary
	t.Log("Summary:")
	t.Logf("  ✓ Round-trip completed: YAML → Bun → YAML")
	t.Logf("  ✓ Schemas: %d", compareResults.Schemas)
	t.Logf("  ✓ Tables: %d", compareResults.Tables)
	t.Logf("  ✓ Columns: %d", compareResults.Columns)
	t.Logf("  ✓ Indexes: %d (original), %d (roundtrip)", compareResults.OriginalIndexes, compareResults.RoundtripIndexes)
	t.Logf("  ✓ Constraints: %d (original), %d (roundtrip)", compareResults.OriginalConstraints, compareResults.RoundtripConstraints)

	if compareResults.OriginalIndexes != compareResults.RoundtripIndexes {
		t.Logf("  ⚠ Note: Index counts differ - Bun reader may not parse all index information from Go code")
	}
	if compareResults.OriginalConstraints != compareResults.RoundtripConstraints {
		t.Logf("  ⚠ Note: Constraint counts differ - Bun reader may not parse all constraint information from Go code")
	}
}

// TestYAMLToGORMRoundTrip tests YAML → GORM Go → YAML roundtrip
func TestYAMLToGORMRoundTrip(t *testing.T) {
	testDir := t.TempDir()

	// Step 1: Read YAML file
	t.Log("Step 1: Reading YAML file...")
	yamlPath := filepath.Join("..", "assets", "yaml", "complex_database.yaml")
	yamlReaderOpts := &readers.ReaderOptions{
		FilePath: yamlPath,
	}
	yamlReader := yamlreader.NewReader(yamlReaderOpts)

	dbFromYAML, err := yamlReader.ReadDatabase()
	require.NoError(t, err, "Failed to read YAML file")
	require.NotNil(t, dbFromYAML, "Database from YAML should not be nil")
	t.Logf("  ✓ Read database '%s' with %d schemas", dbFromYAML.Name, len(dbFromYAML.Schemas))

	// Log initial stats
	totalTables, totalIndexes, totalConstraints := countDatabaseStats(dbFromYAML)
	t.Logf("  ✓ Original: %d tables, %d indexes, %d constraints", totalTables, totalIndexes, totalConstraints)

	// Step 2: Write to GORM Go code
	t.Log("Step 2: Writing to GORM Go code...")
	gormGoPath := filepath.Join(testDir, "models_gorm.go")
	gormWriterOpts := &writers.WriterOptions{
		OutputPath:  gormGoPath,
		PackageName: "models",
		Metadata: map[string]interface{}{
			"generate_table_name": true,
			"generate_get_id":     false,
		},
	}
	gormWriter := gormwriter.NewWriter(gormWriterOpts)

	err = gormWriter.WriteDatabase(dbFromYAML)
	require.NoError(t, err, "Failed to write GORM Go code")

	gormStat, err := os.Stat(gormGoPath)
	require.NoError(t, err, "GORM Go file should exist")
	require.Greater(t, gormStat.Size(), int64(0), "GORM Go file should not be empty")
	t.Logf("  ✓ Wrote GORM Go file (%d bytes)", gormStat.Size())

	// Step 3: Read GORM Go code back
	t.Log("Step 3: Reading GORM Go code back...")
	gormReaderOpts := &readers.ReaderOptions{
		FilePath: gormGoPath,
	}
	gormReader := gormreader.NewReader(gormReaderOpts)

	dbFromGORM, err := gormReader.ReadDatabase()
	require.NoError(t, err, "Failed to read GORM Go code")
	require.NotNil(t, dbFromGORM, "Database from GORM should not be nil")
	t.Logf("  ✓ Read database from GORM with %d schemas", len(dbFromGORM.Schemas))

	// Step 4: Write back to YAML
	t.Log("Step 4: Writing back to YAML...")
	yaml2Path := filepath.Join(testDir, "roundtrip.yaml")
	yamlWriter2Opts := &writers.WriterOptions{
		OutputPath: yaml2Path,
	}
	yamlWriter2 := yamlwriter.NewWriter(yamlWriter2Opts)

	err = yamlWriter2.WriteDatabase(dbFromGORM)
	require.NoError(t, err, "Failed to write YAML")

	yaml2Stat, err := os.Stat(yaml2Path)
	require.NoError(t, err, "Second YAML file should exist")
	require.Greater(t, yaml2Stat.Size(), int64(0), "Second YAML file should not be empty")
	t.Logf("  ✓ Wrote second YAML file (%d bytes)", yaml2Stat.Size())

	// Step 5: Compare YAML files
	t.Log("Step 5: Comparing YAML outputs...")

	// Read both YAML files
	yaml1Data, err := os.ReadFile(yamlPath)
	require.NoError(t, err, "Failed to read first YAML")

	yaml2Data, err := os.ReadFile(yaml2Path)
	require.NoError(t, err, "Failed to read second YAML")

	// Parse into Database models for comparison
	var db1, db2 models.Database
	err = yaml.Unmarshal(yaml1Data, &db1)
	require.NoError(t, err, "Failed to parse first YAML")

	err = yaml.Unmarshal(yaml2Data, &db2)
	require.NoError(t, err, "Failed to parse second YAML")

	// Comprehensive comparison
	compareResults := compareDatabases(t, &db1, &db2, "GORM")

	// Summary
	t.Log("Summary:")
	t.Logf("  ✓ Round-trip completed: YAML → GORM → YAML")
	t.Logf("  ✓ Schemas: %d", compareResults.Schemas)
	t.Logf("  ✓ Tables: %d", compareResults.Tables)
	t.Logf("  ✓ Columns: %d", compareResults.Columns)
	t.Logf("  ✓ Indexes: %d (original), %d (roundtrip)", compareResults.OriginalIndexes, compareResults.RoundtripIndexes)
	t.Logf("  ✓ Constraints: %d (original), %d (roundtrip)", compareResults.OriginalConstraints, compareResults.RoundtripConstraints)

	if compareResults.OriginalIndexes != compareResults.RoundtripIndexes {
		t.Logf("  ⚠ Note: Index counts differ - GORM reader may not parse all index information from Go code")
	}
	if compareResults.OriginalConstraints != compareResults.RoundtripConstraints {
		t.Logf("  ⚠ Note: Constraint counts differ - GORM reader may not parse all constraint information from Go code")
	}
}