import type {
  CheckInfo,
  ColumnInfo,
  ColumnReference,
  ConstraintInfo,
  DatabaseInfo,
  EngineDriver,
  ForeignKeyInfo,
  IndexInfo,
  NamedObjectInfo,
  PrimaryKeyInfo,
  SqlDialect,
  SqlObjectInfo,
  TableInfo,
  UniqueInfo,
  ViewInfo,
} from 'dbgate-types';
import uuidv1 from 'uuid/v1';
import { AlterPlan } from './alterPlan';
import stableStringify from 'json-stable-stringify';
import toposort from 'toposort';
import _omit from 'lodash/omit';
import _cloneDeep from 'lodash/cloneDeep';
import _isEqual from 'lodash/isEqual';
import _pick from 'lodash/pick';
import _compact from 'lodash/compact';
import _isString from 'lodash/isString';
import { detectChangesInPreloadedRows } from './structureTools';

type DbDiffSchemaMode = 'strict' | 'ignore' | 'ignoreImplicit';

export interface DbDiffOptions {
  // allowRecreateTable?: boolean;
  // allowRecreateConstraint?: boolean;
  // allowRecreateSpecificObject?: boolean;
  // allowPairRenamedTables?: boolean;

  ignoreCase?: boolean;
  schemaMode?: DbDiffSchemaMode;
  leftImplicitSchema?: string;
  rightImplicitSchema?: string;
  ignoreConstraintNames?: boolean;

  noDropTable?: boolean;
  allowTableRecreate?: boolean;
  deletedTablePrefix?: string;

  noDropColumn?: boolean;
  deletedColumnPrefix?: string;

  noDropConstraint?: boolean;

  // unlike tables, sql objects could be recreated, when this option is set
  noDropSqlObject?: boolean;
  deletedSqlObjectPrefix?: string;

  noRenameTable?: boolean;
  noRenameColumn?: boolean;

  ignoreForeignKeyActions?: boolean;
  ignoreDataTypes?: boolean;
  ignoreComments?: boolean;
}

export function generateTablePairingId(table: TableInfo): TableInfo {
  if (!table) return table;
  if (!table.pairingId) {
    return {
      ...table,
      primaryKey: table.primaryKey && {
        ...table.primaryKey,
        pairingId: table.primaryKey.pairingId || uuidv1(),
      },
      sortingKey: table.sortingKey && {
        ...table.sortingKey,
        pairingId: table.sortingKey.pairingId || uuidv1(),
      },
      columns: table.columns?.map(col => ({
        ...col,
        pairingId: col.pairingId || uuidv1(),
      })),
      foreignKeys: table.foreignKeys?.map(cnt => ({
        ...cnt,
        pairingId: cnt.pairingId || uuidv1(),
      })),
      checks: table.checks?.map(cnt => ({
        ...cnt,
        pairingId: cnt.pairingId || uuidv1(),
      })),
      indexes: table.indexes?.map(cnt => ({
        ...cnt,
        pairingId: cnt.pairingId || uuidv1(),
      })),
      uniques: table.uniques?.map(cnt => ({
        ...cnt,
        pairingId: cnt.pairingId || uuidv1(),
      })),
      pairingId: table.pairingId || uuidv1(),
    };
  }
  return table;
}

export function removeTablePairingId(table: TableInfo): TableInfo {
  if (!table) return table;
  return {
    ...table,
    columns: table.columns?.map(col => ({
      ...col,
      pairingId: undefined,
    })),
    foreignKeys: table.foreignKeys?.map(cnt => ({
      ...cnt,
      pairingId: undefined,
    })),
    checks: table.checks?.map(cnt => ({
      ...cnt,
      pairingId: undefined,
    })),
    indexes: table.indexes?.map(cnt => ({
      ...cnt,
      pairingId: undefined,
    })),
    uniques: table.uniques?.map(cnt => ({
      ...cnt,
      pairingId: undefined,
    })),
    pairingId: undefined,
  };
}

function simplifySqlExpression(sql: string) {
  return (sql || '')
    .replace(/[\s\(\)\[\]\"]/g, '')
    .toLowerCase()
    .trim();
}

function generateObjectPairingId(obj) {
  if (obj.objectTypeField)
    return {
      ...obj,
      pairingId: obj.pairingId || uuidv1(),
    };
  return obj;
}

export function generateDbPairingId(db: DatabaseInfo): DatabaseInfo {
  if (!db) return db;

  return {
    ...db,
    // ..._.mapValues(db, v => (_.isArray(v) ? v.map(generateObjectPairingId) : v)),
    tables: db.tables?.map(generateTablePairingId),
    views: db.views?.map(generateObjectPairingId),
    procedures: db.procedures?.map(generateObjectPairingId),
    functions: db.functions?.map(generateObjectPairingId),
    triggers: db.triggers?.map(generateObjectPairingId),
    schedulerEvents: db.schedulerEvents?.map(generateObjectPairingId),
    matviews: db.matviews?.map(generateObjectPairingId),
  };
}

function getNameWithoutDeletedPrefix(name: string, opts: DbDiffOptions, deletedPrefix?: string) {
  if (deletedPrefix) {
    if (opts.ignoreCase) {
      if ((name || '').toLowerCase().startsWith(deletedPrefix.toLowerCase())) {
        return name.slice(deletedPrefix.length);
      }
    } else {
      if ((name || '').startsWith(deletedPrefix)) {
        return name.slice(deletedPrefix.length);
      }
    }
  }

  return name;
}

export function hasDeletedPrefix(name: string, opts: DbDiffOptions, deletedPrefix?: string) {
  if (deletedPrefix) {
    if (opts.ignoreCase) {
      return (name || '').toLowerCase().startsWith(deletedPrefix.toLowerCase());
    } else {
      return (name || '').startsWith(deletedPrefix);
    }
  }
  return false;
}

function testEqualNames(a: string, b: string, opts: DbDiffOptions, deletedPrefix?: string) {
  a = getNameWithoutDeletedPrefix(a, opts, deletedPrefix);
  b = getNameWithoutDeletedPrefix(b, opts, deletedPrefix);
  if (opts.ignoreCase) return (a || '').toLowerCase() == (b || '').toLowerCase();
  return a == b;
}

function testEqualSchemas(lschema: string, rschema: string, opts: DbDiffOptions) {
  if (opts.schemaMode == 'ignore') lschema = null;
  if (opts.schemaMode == 'ignoreImplicit' && lschema == opts.leftImplicitSchema) lschema = null;
  if (opts.schemaMode == 'ignore') rschema = null;
  if (opts.schemaMode == 'ignoreImplicit' && rschema == opts.rightImplicitSchema) rschema = null;
  return testEqualNames(lschema, rschema, opts);
}

function testEqualFullNames(lft: NamedObjectInfo, rgt: NamedObjectInfo, opts: DbDiffOptions, deletedPrefix?: string) {
  if (lft == null || rgt == null) return lft == rgt;
  return (
    testEqualSchemas(lft.schemaName, rgt.schemaName, opts) &&
    testEqualNames(lft.pureName, rgt.pureName, opts, deletedPrefix)
  );
}

function testEqualDefaultValues(value1: string | null | undefined, value2: string | null | undefined) {
  if (value1 == null) return value2 == null || value2 == 'NULL';
  if (value2 == null) return value1 == null || value1 == 'NULL';
  if (_isString(value1) && _isString(value2)) {
    value1 = value1.trim();
    value2 = value2.trim();
    if (value1.startsWith("'") && value1.endsWith("'") && value2.startsWith("'") && value2.endsWith("'")) {
      return value1 == value2;
    }
    return value1.toLowerCase() == value2.toLowerCase();
  }
  return value1 == value2;
}

export function testEqualColumns(
  a: ColumnInfo,
  b: ColumnInfo,
  checkName: boolean,
  checkDefault: boolean,
  opts: DbDiffOptions = {}
) {
  if (checkName && !testEqualNames(a.columnName, b.columnName, opts)) {
    // opts.DiffLogger.Trace("Column, different name: {0}; {1}", a, b);
    return false;
  }
  //if (!DbDiffTool.EqualFullNames(a.Domain, b.Domain, opts))
  //{
  //    opts.DiffLogger.Trace("Column {0}, {1}: different domain: {2}; {3}", a, b, a.Domain, b.Domain);
  //    return false;
  //}
  if (a.computedExpression != b.computedExpression) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different computed expression: ${a.computedExpression}, ${b.computedExpression}`
    );
    // opts.DiffLogger.Trace(
    //   'Column {0}, {1}: different computed expression: {2}; {3}',
    //   a,
    //   b,
    //   a.ComputedExpression,
    //   b.ComputedExpression
    // );
    return false;
  }
  if (a.computedExpression != null) {
    return true;
  }
  if (checkDefault) {
    if (!testEqualDefaultValues(a.defaultValue, b.defaultValue)) {
      console.debug(
        `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different default value: ${a.defaultValue}, ${b.defaultValue}`
      );

      // opts.DiffLogger.Trace(
      //   'Column {0}, {1}: different default values: {2}; {3}',
      //   a,
      //   b,
      //   a.DefaultValue,
      //   b.DefaultValue
      // );
      return false;
    }
    if (a.defaultConstraint != b.defaultConstraint) {
      console.debug(
        `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different default constraint: ${a.defaultConstraint}, ${b.defaultConstraint}`
      );

      // opts.DiffLogger.Trace(
      //   'Column {0}, {1}: different default constraint names: {2}; {3}',
      //   a,
      //   b,
      //   a.DefaultConstraint,
      //   b.DefaultConstraint
      // );
      return false;
    }
  }
  if ((a.notNull || false) != (b.notNull || false)) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different nullability: ${a.notNull}, ${b.notNull}`
    );

    // opts.DiffLogger.Trace('Column {0}, {1}: different nullable: {2}; {3}', a, b, a.NotNull, b.NotNull);
    return false;
  }
  if ((a.autoIncrement || false) != (b.autoIncrement || false)) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different autoincrement: ${a.autoIncrement}, ${b.autoIncrement}`
    );

    // opts.DiffLogger.Trace('Column {0}, {1}: different autoincrement: {2}; {3}', a, b, a.AutoIncrement, b.AutoIncrement);
    return false;
  }
  if ((a.isSparse || false) != (b.isSparse || false)) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different is_sparse: ${a.isSparse}, ${b.isSparse}`
    );

    // opts.DiffLogger.Trace('Column {0}, {1}: different is_sparse: {2}; {3}', a, b, a.IsSparse, b.IsSparse);
    return false;
  }
  if ((a.isUnsigned || false) != (b.isUnsigned || false)) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different unsigned: ${a.isUnsigned}, ${b.isUnsigned}`
    );
    return false;
  }
  if ((a.isZerofill || false) != (b.isZerofill || false)) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different zerofill: ${a.isZerofill}, ${b.isZerofill}`
    );
    return false;
  }

  if (!opts.ignoreComments) {
    if ((a.columnComment || '') != (b.columnComment || '')) {
      console.debug(
        `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different comment: ${a.columnComment}, ${b.columnComment}`
      );
      return false;
    }
  }

  if (!testEqualTypes(a, b, opts)) {
    return false;
  }

  //var btype = b.DataType;
  //var atype = a.DataType;
  //if (pairing != null && pairing.Target != null && pairing.Source.Dialect != null)
  //{
  //    btype = pairing.Source.Dialect.MigrateDataType(b, btype, pairing.Source.Dialect.GetDefaultMigrationProfile(), null);
  //    btype = pairing.Source.Dialect.GenericTypeToSpecific(btype).ToGenericType();

  //    // normalize type
  //    atype = pairing.Source.Dialect.GenericTypeToSpecific(atype).ToGenericType();
  //}
  //if (!EqualTypes(atype, btype, opts))
  //{
  //    opts.DiffLogger.Trace("Column {0}, {1}: different types: {2}; {3}", a, b, a.DataType, b.DataType);
  //    return false;
  //}
  //if (!opts.IgnoreColumnCollation && a.Collation != b.Collation)
  //{
  //    opts.DiffLogger.Trace("Column {0}, {1}: different collations: {2}; {3}", a, b, a.Collation, b.Collation);
  //    return false;
  //}
  //if (!opts.IgnoreColumnCharacterSet && a.CharacterSet != b.CharacterSet)
  //{
  //    opts.DiffLogger.Trace("Column {0}, {1}: different character sets: {2}; {3}", a, b, a.CharacterSet, b.CharacterSet);
  //    return false;
  //}
  return true;
}

function testEqualColumnRefs(a: ColumnReference[], b: ColumnReference[], opts: DbDiffOptions) {
  if (a.length != b.length) return false;
  for (let i = 0; i < a.length; i++) {
    if (!testEqualNames(a[i].columnName, b[i].columnName, opts)) return false;
    if (!testEqualNames(a[i].refColumnName, b[i].refColumnName, opts)) return false;
  }
  return true;
}

function testEqualPrimaryKeys(a: PrimaryKeyInfo, b: PrimaryKeyInfo, opts: DbDiffOptions) {
  if (!testEqualColumnRefs(a.columns, b.columns, opts)) return false;
  return true;
}

function testEqualForeignKeys(a: ForeignKeyInfo, b: ForeignKeyInfo, opts: DbDiffOptions) {
  if (!testEqualColumnRefs(a.columns, b.columns, opts)) return false;
  if (!opts.ignoreConstraintNames && !testEqualNames(a.constraintName, b.constraintName, opts)) return false;
  return true;
}

function testEqualIndex(a: IndexInfo, b: IndexInfo, opts: DbDiffOptions) {
  if (!testEqualColumnRefs(a.columns, b.columns, opts)) return false;
  if (!!a.isUnique != !!b.isUnique) return false;
  if (simplifySqlExpression(a.filterDefinition) != simplifySqlExpression(b.filterDefinition)) return false;

  if (!opts.ignoreConstraintNames && !testEqualNames(a.constraintName, b.constraintName, opts)) return false;
  return true;
}

function testEqualUnique(a: UniqueInfo, b: UniqueInfo, opts: DbDiffOptions) {
  if (!testEqualColumnRefs(a.columns, b.columns, opts)) return false;

  if (!opts.ignoreConstraintNames && !testEqualNames(a.constraintName, b.constraintName, opts)) return false;
  return true;
}

function testEqualCheck(a: CheckInfo, b: CheckInfo, opts: DbDiffOptions) {
  if (a.definition != b.definition) return false;
  if (!opts.ignoreConstraintNames && !testEqualNames(a.constraintName, b.constraintName, opts)) return false;
  return true;
}

function testEqualConstraints(a: ConstraintInfo, b: ConstraintInfo, opts: DbDiffOptions = {}) {
  if (a.constraintType != b.constraintType) {
    console.debug(`Constraint ${a.pureName}: different constraint type: ${a.constraintType}, ${b.constraintType}`);
    return false;
  }

  switch (a.constraintType) {
    case 'primaryKey':
    case 'sortingKey':
      return testEqualPrimaryKeys(a as PrimaryKeyInfo, b as PrimaryKeyInfo, opts);
    case 'foreignKey':
      return testEqualForeignKeys(a as ForeignKeyInfo, b as ForeignKeyInfo, opts);
    case 'index':
      return testEqualIndex(a as IndexInfo, b as IndexInfo, opts);
    case 'unique':
      return testEqualUnique(a as UniqueInfo, b as UniqueInfo, opts);
    case 'check':
      return testEqualCheck(a as CheckInfo, b as CheckInfo, opts);
  }

  console.debug(`Unknown constraint type: ${a.pureName}`);

  return false;

  // const omitList = ['pairingId'];
  // if (opts.ignoreForeignKeyActions) {
  //   omitList.push('updateAction');
  //   omitList.push('deleteAction');
  // }
  // if (opts.ignoreConstraintNames) {
  //   omitList.push('constraintName');
  // }
  // if (opts.schemaMode == 'ignore') {
  //   omitList.push('schemaName');
  //   omitList.push('refSchemaName');
  // }

  // if (a.constraintType == 'primaryKey' && b.constraintType == 'primaryKey') {
  //   console.log('PK1', stableStringify(_.omit(a, omitList)));
  //   console.log('PK2', stableStringify(_.omit(b, omitList)));
  // }

  // if (a.constraintType == 'foreignKey' && b.constraintType == 'foreignKey') {
  //   console.log('FK1', stableStringify(_omit(a, omitList)));
  //   console.log('FK2', stableStringify(_omit(b, omitList)));
  // }

  // if (a.constraintType == 'index' && b.constraintType == 'index') {
  //   console.log('IX1', stableStringify(_omit(a, omitList)));
  //   console.log('IX2', stableStringify(_omit(b, omitList)));
  // }

  // const aStringified = stableStringify(_omit(a, omitList));
  // const bStringified = stableStringify(_omit(b, omitList));

  // return aStringified == bStringified;
}

export function testEqualTypes(a: ColumnInfo, b: ColumnInfo, opts: DbDiffOptions = {}) {
  if (opts.ignoreDataTypes) {
    return true;
  }

  if (simplifySqlExpression(a.dataType) != simplifySqlExpression(b.dataType)) {
    console.debug(
      `Column ${a.pureName}.${a.columnName}, ${b.pureName}.${b.columnName}: different data type: ${a.dataType}, ${b.dataType}`
    );
    return false;
  }

  return true;
}

function getTableConstraints(table: TableInfo) {
  const res = [];
  if (table.primaryKey) res.push(table.primaryKey);
  if (table.sortingKey) res.push(table.sortingKey);
  if (table.foreignKeys) res.push(...table.foreignKeys);
  if (table.indexes) res.push(...table.indexes);
  if (table.uniques) res.push(...table.uniques);
  if (table.checks) res.push(...table.checks);
  return res;
}

function createPairs(oldList, newList, additionalCondition = null) {
  const res = [];
  for (const a of oldList) {
    const b = newList.find(
      x => (a.pairingId && x.pairingId == a.pairingId) || (additionalCondition && additionalCondition(a, x))
    );
    if (b) {
      res.push([a, b]);
    } else {
      res.push([a, null]);
    }
  }
  for (const b of newList) {
    if (!res.find(x => x[1] == b)) {
      res.push([null, b]);
    }
  }
  return res;
}

function planTablePreload(plan: AlterPlan, oldTable: TableInfo, newTable: TableInfo) {
  const key = newTable.preloadedRowsKey || newTable.primaryKey?.columns?.map(x => x.columnName);
  if (newTable.preloadedRows?.length > 0 && key?.length > 0 && detectChangesInPreloadedRows(oldTable, newTable)) {
    plan.fillPreloadedRows(
      newTable,
      oldTable?.preloadedRows,
      newTable.preloadedRows,
      key,
      newTable.preloadedRowsInsertOnly,
      newTable.columns.find(x => x.autoIncrement)?.columnName
    );
  }
}

function planAlterTable(plan: AlterPlan, oldTable: TableInfo, newTable: TableInfo, opts: DbDiffOptions) {
  // if (oldTable.primaryKey)

  const columnPairs = createPairs(oldTable.columns, newTable.columns);
  const constraintPairs = createPairs(
    getTableConstraints(oldTable),
    getTableConstraints(newTable),
    (a, b) =>
      (a.constraintType == 'primaryKey' && b.constraintType == 'primaryKey') ||
      (a.constraintType == 'sortingKey' && b.constraintType == 'sortingKey')
  );
  // console.log('constraintPairs OLD TABLE', oldTable);
  // console.log('constraintPairs NEW TABLE', newTable);
  // console.log('constraintPairs SOURCE OLD', getTableConstraints(oldTable));
  // console.log('constraintPairs SOURCE NEW', getTableConstraints(newTable));
  // console.log('constraintPairs', constraintPairs);

  if (!opts.noDropConstraint) {
    constraintPairs.filter(x => x[1] == null).forEach(x => plan.dropConstraint(x[0]));
  }
  if (opts.deletedColumnPrefix) {
    columnPairs
      .filter(x => x[1] == null)
      .forEach(x => {
        if (!hasDeletedPrefix(x[0].columnName, opts, opts.deletedColumnPrefix)) {
          plan.renameColumn(x[0], opts.deletedColumnPrefix + x[0].columnName);
        }
      });
  } else if (!opts.noDropColumn) {
    columnPairs.filter(x => x[1] == null).forEach(x => plan.dropColumn(x[0]));
  }

  if (!testEqualFullNames(oldTable, newTable, opts) && !opts.noRenameTable) {
    plan.renameTable(oldTable, newTable.pureName);
  }

  if (hasDeletedPrefix(oldTable.pureName, opts, opts.deletedTablePrefix)) {
    plan.renameTable(oldTable, newTable.pureName);
  }

  columnPairs.filter(x => x[0] == null).forEach(x => plan.createColumn(x[1]));

  columnPairs
    .filter(x => x[0] && x[1])
    .forEach(x => {
      let srccol: ColumnInfo = x[0];
      let dstcol: ColumnInfo = x[1];
      if (hasDeletedPrefix(srccol.columnName, opts, opts.deletedColumnPrefix)) {
        plan.renameColumn(srccol, dstcol.columnName);
        // rename is already done
        srccol = {
          ...srccol,
          columnName: dstcol.columnName,
        };
      }

      if (!testEqualColumns(srccol, dstcol, true, true, opts)) {
        if (testEqualColumns(srccol, dstcol, false, true, opts) && !opts.noRenameColumn) {
          // console.log('PLAN RENAME COLUMN')
          plan.renameColumn(srccol, dstcol.columnName);
        } else {
          // console.log('PLAN CHANGE COLUMN', x[0], x[1]);
          plan.changeColumn(srccol, dstcol);
        }
      }
    });

  constraintPairs
    .filter(x => x[0] && x[1])
    .forEach(x => {
      if (!testEqualConstraints(x[0], x[1], opts)) {
        // console.log('PLAN CHANGE CONSTRAINT', x[0], x[1]);
        plan.changeConstraint(x[0], x[1]);
      }
    });

  constraintPairs.filter(x => x[0] == null).forEach(x => plan.createConstraint(x[1]));

  planChangeTableOptions(plan, oldTable, newTable, opts);

  // console.log('oldTable', oldTable);
  // console.log('newTable', newTable);
  // console.log('plan.operations', plan.operations);
}

function planChangeTableOptions(plan: AlterPlan, oldTable: TableInfo, newTable: TableInfo, opts: DbDiffOptions) {
  for (const option of plan.dialect?.getTableFormOptions?.('sqlAlterTable') || []) {
    if (option.disabled) {
      continue;
    }
    const name = option.name;
    if (
      oldTable[name] != newTable[name] &&
      (oldTable[name] || newTable[name]) &&
      (newTable[name] || option.allowEmptyValue)
    ) {
      plan.setTableOption(newTable, name, newTable[name]);
    }
  }
}

export function testEqualTables(
  a: TableInfo,
  b: TableInfo,
  opts: DbDiffOptions,
  wholeOldDb: DatabaseInfo,
  wholeNewDb: DatabaseInfo,
  driver: EngineDriver
) {
  const plan = new AlterPlan(wholeOldDb, wholeNewDb, driver.dialect, opts);
  planAlterTable(plan, a, b, opts);
  // if (plan.operations.length > 0) {
  //   console.log('************** plan.operations', a, b, plan.operations);
  // }
  if (plan.operations.length > 0) {
    return false;
  }

  if (detectChangesInPreloadedRows(a, b)) {
    return false;
  }

  return true;
}

export function testEqualSqlObjects(a: SqlObjectInfo, b: SqlObjectInfo, opts: DbDiffOptions) {
  return a.createSql?.trim()?.toLowerCase() == b.createSql?.trim()?.toLowerCase();
}

export function createAlterTablePlan(
  oldTable: TableInfo,
  newTable: TableInfo,
  opts: DbDiffOptions,
  wholeOldDb: DatabaseInfo,
  wholeNewDb: DatabaseInfo,
  driver: EngineDriver
): AlterPlan {
  const plan = new AlterPlan(wholeOldDb, wholeNewDb, driver.dialect, opts);
  if (oldTable == null) {
    plan.createTable(newTable);
    planTablePreload(plan, null, newTable);
  } else if (newTable == null) {
    plan.dropTable(oldTable);
  } else {
    planAlterTable(plan, oldTable, newTable, opts);
    planTablePreload(plan, oldTable, newTable);
  }
  plan.transformPlan();
  return plan;
}

function sortViewsByDependency(views: ViewInfo[]): ViewInfo[] {
  const viewNames: string[] = [];
  const viewDict: { [name: string]: string } = {};

  for (const view of views) {
    if (!viewNames.includes(view.pureName)) {
      viewNames.push(view.pureName);
    }
    viewDict[view.pureName] = viewDict[view.pureName]
      ? `${viewDict[view.pureName]} ${view.createSql}}`
      : view.createSql;
  }

  const edges = [];
  for (const viewName of viewNames) {
    edges.push([viewName, null]);
    const viewText = viewDict[viewName];
    for (const otherView of viewNames) {
      if (otherView === viewName) continue;
      if ((' ' + viewText + ' ').match('[\\W]' + otherView + '[\\W]')) {
        edges.push([otherView, viewName]);
      }
    }
  }

  const ordered: string[] = _compact(toposort(edges));

  const res: ViewInfo[] = [];
  for (const viewName of ordered) {
    res.push(...views.filter(x => x.pureName == viewName));
  }
  return res;
}

export function createAlterDatabasePlan(
  oldDb: DatabaseInfo,
  newDb: DatabaseInfo,
  opts: DbDiffOptions,
  wholeOldDb: DatabaseInfo,
  wholeNewDb: DatabaseInfo,
  driver: EngineDriver
): AlterPlan {
  const plan = new AlterPlan(wholeOldDb, wholeNewDb, driver.dialect, opts);

  for (const objectTypeField of [
    'tables',
    'views',
    'procedures',
    'matviews',
    'functions',
    'triggers',
    'schedulerEvents',
  ]) {
    for (const oldobj of oldDb[objectTypeField] || []) {
      const newobj = (newDb[objectTypeField] || []).find(x => x.pairingId == oldobj.pairingId);
      if (objectTypeField == 'tables') {
        if (newobj == null) {
          if (opts.deletedTablePrefix && !hasDeletedPrefix(oldobj.pureName, opts, opts.deletedTablePrefix)) {
            plan.renameTable(oldobj, opts.deletedTablePrefix + oldobj.pureName);
          } else if (!opts.noDropTable) {
            plan.dropTable(oldobj);
          }
        } else {
          planAlterTable(plan, oldobj, newobj, opts);
          planTablePreload(plan, oldobj, newobj);
        }
      } else {
        if (newobj == null) {
          if (
            opts.deletedSqlObjectPrefix &&
            driver.dialect.renameSqlObject &&
            !hasDeletedPrefix(oldobj.pureName, opts, opts.deletedSqlObjectPrefix)
          ) {
            plan.renameSqlObject(oldobj, opts.deletedSqlObjectPrefix + oldobj.pureName);
          } else if (!opts.noDropSqlObject) {
            plan.dropSqlObject(oldobj);
          }
        } else {
          if (opts.deletedSqlObjectPrefix && hasDeletedPrefix(oldobj.pureName, opts, opts.deletedSqlObjectPrefix)) {
            if (driver.dialect.renameSqlObject && testEqualSqlObjects(oldobj, newobj, opts)) {
              plan.renameSqlObject(oldobj, newobj.pureName);
            } else {
              plan.dropSqlObject(oldobj);
              plan.createSqlObject(newobj);
            }
          } else if (!testEqualSqlObjects(oldobj, newobj, opts)) {
            plan.recreates.sqlObjects += 1;
            plan.dropSqlObject(oldobj);
            plan.createSqlObject(newobj);
          } else if (!testEqualFullNames(oldobj, newobj, opts)) {
            plan.renameSqlObject(oldobj, newobj.pureName);
          }
        }
      }
    }

    let newList = newDb[objectTypeField] || [];
    if (objectTypeField == 'views') {
      newList = sortViewsByDependency(newList);
    }

    for (const newobj of newList) {
      const oldobj = (oldDb[objectTypeField] || []).find(x => x.pairingId == newobj.pairingId);
      if (objectTypeField == 'tables') {
        if (oldobj == null) {
          plan.createTable(newobj);
          planTablePreload(plan, null, newobj);
        }
      } else {
        if (oldobj == null) plan.createSqlObject(newobj);
      }
    }
  }
  plan.transformPlan();
  return plan;
}

export function getAlterTableScript(
  oldTable: TableInfo,
  newTable: TableInfo,
  opts: DbDiffOptions,
  wholeOldDb: DatabaseInfo,
  wholeNewDb: DatabaseInfo,
  driver: EngineDriver
) {
  if ((!oldTable && !newTable) || !driver) {
    return { sql: '', recreates: [] };
  }

  const plan = createAlterTablePlan(oldTable, newTable, opts, wholeOldDb, wholeNewDb, driver);
  const dmp = driver.createDumper({ useHardSeparator: true });
  plan.run(dmp);
  return {
    sql: dmp.s,
    recreates: plan.recreates,
  };
}

export function getAlterDatabaseScript(
  oldDb: DatabaseInfo,
  newDb: DatabaseInfo,
  opts: DbDiffOptions,
  wholeOldDb: DatabaseInfo,
  wholeNewDb: DatabaseInfo,
  driver: EngineDriver,
  transformPlan: (plan: AlterPlan) => void = null
) {
  const plan = createAlterDatabasePlan(oldDb, newDb, opts, wholeOldDb, wholeNewDb, driver);
  if (transformPlan) {
    transformPlan(plan);
  }
  const dmp = driver.createDumper({ useHardSeparator: true });
  plan.run(dmp);
  return {
    sql: dmp.s,
    recreates: plan.recreates,
    isEmpty: plan.operations.length == 0,
  };
}

export function matchPairedObjects(db1: DatabaseInfo, db2: DatabaseInfo, opts: DbDiffOptions): DatabaseInfo {
  if (!db1 || !db2) return null;

  const res = _cloneDeep(db2);

  for (const objectTypeField of ['tables', 'views', 'procedures', 'matviews', 'functions']) {
    for (const obj2 of res[objectTypeField] || []) {
      const obj1 = db1[objectTypeField].find(x =>
        testEqualFullNames(
          x,
          obj2,
          opts,
          objectTypeField == 'tables' ? opts.deletedTablePrefix : opts.deletedSqlObjectPrefix
        )
      );
      if (obj1) {
        obj2.pairingId = obj1.pairingId;

        if (objectTypeField == 'tables') {
          for (const col2 of obj2.columns) {
            const col1 = obj1.columns.find(x =>
              testEqualNames(x.columnName, col2.columnName, opts, opts.deletedColumnPrefix)
            );
            if (col1) col2.pairingId = col1.pairingId;
          }

          for (const fk2 of obj2.foreignKeys) {
            const fk1 = obj1.foreignKeys.find(
              x =>
                testEqualNames(x.refTableName, fk2.refTableName, opts) &&
                _isEqual(
                  x.columns.map(y => _pick(y, ['columnName', 'refColumnName'])),
                  fk2.columns.map(y => _pick(y, ['columnName', 'refColumnName']))
                )
            );
            if (fk1) fk2.pairingId = fk1.pairingId;
          }

          for (const uq2 of obj2.uniques) {
            const uq1 = obj1.uniques.find(x =>
              _isEqual(
                x.columns.map(y => _pick(y, ['columnName'])),
                uq2.columns.map(y => _pick(y, ['columnName']))
              )
            );
            if (uq1) uq2.pairingId = uq1.pairingId;
          }

          for (const ix2 of obj2.indexes) {
            const ix1 = obj1.indexes.find(x => testEqualNames(x.constraintName, ix2.constraintName, opts));
            if (ix1) ix2.pairingId = ix1.pairingId;
          }
        }
      }
    }
  }

  return res;
}

export const modelCompareDbDiffOptions: DbDiffOptions = {
  ignoreCase: true,
  ignoreConstraintNames: true,
  ignoreForeignKeyActions: true,
  ignoreDataTypes: true,
};