package model

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

	"github.com/QuantumNous/new-api/common"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	"gorm.io/gorm"
)

type MigrationIdentityFields struct {
	ID        int    `gorm:"primaryKey"`
	Name      string `gorm:"size:64;unique"`
	Reference string `gorm:"size:64;uniqueIndex"`
	Provider  string `gorm:"size:32;uniqueIndex:,composite:provider_subject"`
	Subject   string `gorm:"size:64;uniqueIndex:,composite:provider_subject"`
}

type migrationIdentityV1 struct {
	MigrationIdentityFields
	Digest string `gorm:"type:char(32)"`
}

type migrationIdentityV2 struct {
	MigrationIdentityFields
	Digest string `gorm:"type:char(64)"`
	Note   string `gorm:"size:128"`
}

type migrationConstraintV1 struct {
	ID   int    `gorm:"primaryKey"`
	Name string `gorm:"size:64"`
}

type migrationConstraintV2 struct {
	ID   int    `gorm:"primaryKey"`
	Name string `gorm:"size:64;unique"`
}

type migrationDecimalV1 struct {
	ID    int     `gorm:"primaryKey"`
	Price float64 `gorm:"type:decimal(10,6);default:0"`
}

type migrationDecimalV2 struct {
	ID    int     `gorm:"primaryKey"`
	Price float64 `gorm:"type:decimal(12,6);not null;default:0"`
}

type migrationDecimalV3 struct {
	ID    int     `gorm:"primaryKey"`
	Price float64 `gorm:"type:decimal(12,6);not null;default:1.25"`
}

func TestMigrationSchemaStability(t *testing.T) {
	for _, dialect := range []string{"sqlite", "mysql", "postgres"} {
		t.Run(dialect, func(t *testing.T) {
			var dsn string
			switch dialect {
			case "sqlite":
				dsn = "local"
				previousPath := common.SQLitePath
				common.SQLitePath = filepath.Join(t.TempDir(), "migration.db")
				t.Cleanup(func() { common.SQLitePath = previousPath })
			case "mysql":
				dsn = os.Getenv("TEST_MYSQL_DSN")
			case "postgres":
				dsn = os.Getenv("TEST_POSTGRES_DSN")
			}
			if dsn == "" {
				t.Skip("test database DSN is not configured")
			}
			t.Setenv("MIGRATION_TEST_DSN", dsn)
			db, _, err := chooseDB("MIGRATION_TEST_DSN", false)
			require.NoError(t, err)
			sqlDB, err := db.DB()
			require.NoError(t, err)
			t.Cleanup(func() { _ = sqlDB.Close() })
			recorder := &migrationSQLRecorder{}
			db = db.Session(&gorm.Session{Logger: recorder})

			t.Run("identity_and_indexes", func(t *testing.T) {
				const table = "migration_identity_test"
				t.Cleanup(func() { _ = db.Migrator().DropTable(table) })
				require.NoError(t, db.Table(table).AutoMigrate(&migrationIdentityV1{}))
				row := migrationIdentityV1{
					MigrationIdentityFields: MigrationIdentityFields{ID: 1, Name: "root", Reference: "token-reference", Provider: "oidc", Subject: "subject"},
					Digest:                  "old-digest",
				}
				require.NoError(t, db.Table(table).Create(&row).Error)
				recorder.reset()
				require.NoError(t, db.Table(table).AutoMigrate(&migrationIdentityV1{}))
				assert.Empty(t, recorder.schemaMutations())

				require.NoError(t, db.Table(table).AutoMigrate(&migrationIdentityV2{}))
				columns, err := db.Table(table).Migrator().ColumnTypes(&migrationIdentityV2{})
				require.NoError(t, err)
				for _, column := range columns {
					if column.Name() == "digest" {
						length, ok := column.Length()
						require.True(t, ok)
						assert.EqualValues(t, 64, length)
					}
				}
				assert.True(t, db.Table(table).Migrator().HasColumn(&migrationIdentityV2{}, "note"))
				recorder.reset()
				require.NoError(t, db.Table(table).AutoMigrate(&migrationIdentityV2{}))
				assert.Empty(t, recorder.schemaMutations())
				var saved migrationIdentityV2
				require.NoError(t, db.Table(table).First(&saved, 1).Error)
				assert.Equal(t, row.MigrationIdentityFields, saved.MigrationIdentityFields)
				expectedDigest := row.Digest
				if dialect == "postgres" {
					expectedDigest += strings.Repeat(" ", 64-len(row.Digest))
				}
				assert.Equal(t, expectedDigest, saved.Digest)
				for _, duplicate := range []migrationIdentityV2{
					{MigrationIdentityFields: MigrationIdentityFields{Name: "root", Reference: "other-1", Provider: "other", Subject: "1"}},
					{MigrationIdentityFields: MigrationIdentityFields{Name: "other-2", Reference: "token-reference", Provider: "other", Subject: "2"}},
					{MigrationIdentityFields: MigrationIdentityFields{Name: "other-3", Reference: "other-3", Provider: "oidc", Subject: "subject"}},
				} {
					assert.Error(t, db.Table(table).Create(&duplicate).Error)
				}
			})

			t.Run("unique_constraint_changes", func(t *testing.T) {
				const table = "migration_constraint_test"
				t.Cleanup(func() { _ = db.Migrator().DropTable(table) })
				require.NoError(t, db.Table(table).AutoMigrate(&migrationConstraintV1{}))
				require.NoError(t, db.Table(table).Create(&migrationConstraintV1{Name: "existing"}).Error)
				require.NoError(t, db.Table(table).AutoMigrate(&migrationConstraintV2{}))
				assert.Error(t, db.Table(table).Create(&migrationConstraintV2{Name: "existing"}).Error)
				recorder.reset()
				require.NoError(t, db.Table(table).AutoMigrate(&migrationConstraintV2{}))
				assert.Empty(t, recorder.schemaMutations())
				require.NoError(t, db.Table(table).AutoMigrate(&migrationConstraintV1{}))
				require.NoError(t, db.Table(table).Create(&migrationConstraintV1{Name: "existing"}).Error)
			})

			if dialect == "mysql" {
				t.Run("decimal_default_and_real_changes", func(t *testing.T) {
					const table = "migration_decimal_test"
					t.Cleanup(func() { _ = db.Migrator().DropTable(table) })
					require.NoError(t, db.Table(table).AutoMigrate(&migrationDecimalV1{}))
					require.NoError(t, db.Table(table).Create(&migrationDecimalV1{ID: 1, Price: 12.345678}).Error)
					for _, target := range []any{&migrationDecimalV1{}, &migrationDecimalV2{}, &migrationDecimalV3{}} {
						require.NoError(t, db.Table(table).AutoMigrate(target))
						recorder.reset()
						require.NoError(t, db.Table(table).AutoMigrate(target))
						assert.Empty(t, recorder.schemaMutations())
					}
					columns, err := db.Table(table).Migrator().ColumnTypes(&migrationDecimalV3{})
					require.NoError(t, err)
					for _, column := range columns {
						if column.Name() == "price" {
							precision, scale, ok := column.DecimalSize()
							require.True(t, ok)
							assert.EqualValues(t, 12, precision)
							assert.EqualValues(t, 6, scale)
							nullable, ok := column.Nullable()
							require.True(t, ok)
							assert.False(t, nullable)
						}
					}
					require.NoError(t, db.Table(table).Create(&map[string]any{"id": 2}).Error)
					var prices []float64
					require.NoError(t, db.Table(table).Order("id").Pluck("price", &prices).Error)
					assert.Equal(t, []float64{12.345678, 1.25}, prices)
				})
			}
		})
	}
}