package database

import (
	"errors"
	"strings"
	"testing"

	"gorm.io/gorm"
)

func TestMigrateSchemaRecordsAndValidatesVersion(t *testing.T) {
	db, err := Open(Config{Driver: "sqlite", DSN: "file:migration-version?mode=memory&cache=shared"})
	if err != nil {
		t.Fatal(err)
	}
	if err := MigrateSchema(db); err != nil {
		t.Fatal(err)
	}
	status, err := ReadSchemaStatus(db)
	if err != nil {
		t.Fatal(err)
	}
	if !status.Ready || status.Current != CurrentSchemaVersion {
		t.Fatalf("unexpected schema status: %#v", status)
	}
	if !db.Migrator().HasIndex(&schemaMigration{}, "idx_schema_migrations_applied_at") {
		t.Fatal("schema migration v2 did not create the applied_at index")
	}
	if err := MigrateSchema(db); err != nil {
		t.Fatalf("migration should be idempotent: %v", err)
	}
}

func TestMigrateSchemaRejectsChecksumMismatch(t *testing.T) {
	db, err := Open(Config{Driver: "sqlite", DSN: "file:migration-checksum?mode=memory&cache=shared"})
	if err != nil {
		t.Fatal(err)
	}
	if err := MigrateSchema(db); err != nil {
		t.Fatal(err)
	}
	if err := db.Model(&schemaMigration{}).Where("version = ?", CurrentSchemaVersion).Update("checksum", "changed").Error; err != nil {
		t.Fatal(err)
	}
	if err := MigrateSchema(db); err == nil || !strings.Contains(err.Error(), "校验和不一致") {
		t.Fatalf("expected checksum mismatch, got %v", err)
	}
	if err := RequireSchemaVersion(db); err == nil || !strings.Contains(err.Error(), "校验和不一致") {
		t.Fatalf("schema verification must reject checksum mismatch, got %v", err)
	}
}

func TestMigrateSchemaRollsBackFailedMigration(t *testing.T) {
	db, err := Open(Config{Driver: "sqlite", DSN: "file:migration-rollback?mode=memory&cache=shared"})
	if err != nil {
		t.Fatal(err)
	}
	if err := MigrateSchema(db); err != nil {
		t.Fatal(err)
	}

	original := schemaMigrations
	schemaMigrations = append(append([]migration(nil), original...), migration{
		version:  CurrentSchemaVersion + 1,
		name:     "rollback_probe",
		checksum: "sha256:rollback-probe",
		apply: func(tx *gorm.DB) error {
			if err := tx.Exec("CREATE TABLE migration_rollback_probe (id INTEGER PRIMARY KEY)").Error; err != nil {
				return err
			}
			return errors.New("forced migration failure")
		},
	})
	t.Cleanup(func() { schemaMigrations = original })

	if err := MigrateSchema(db); err == nil || !strings.Contains(err.Error(), "forced migration failure") {
		t.Fatalf("expected forced migration failure, got %v", err)
	}
	if db.Migrator().HasTable("migration_rollback_probe") {
		t.Fatal("failed migration left a partial table behind")
	}
	var count int64
	if err := db.Model(&schemaMigration{}).Where("version = ?", CurrentSchemaVersion+1).Count(&count).Error; err != nil {
		t.Fatal(err)
	}
	if count != 0 {
		t.Fatalf("failed migration was recorded: %d", count)
	}
}

func TestRequireSchemaVersionRejectsUninitializedDatabase(t *testing.T) {
	db, err := Open(Config{Driver: "sqlite", DSN: "file:migration-uninitialized?mode=memory&cache=shared"})
	if err != nil {
		t.Fatal(err)
	}
	if err := RequireSchemaVersion(db); err == nil || !strings.Contains(err.Error(), "请先执行 migrate-schema up") {
		t.Fatalf("expected missing migration error, got %v", err)
	}
}