/**
 * Copyright (c) 2020-present, Goldman Sachs
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/***************************************************************************************
 * [CORE]
 *
 * These are utilities used to build the executable query from the snapshot.
 * The executable query is then used to fetch data.
 ***************************************************************************************/

import {
  type V1_PrimitiveValueSpecification,
  type V1_ValueSpecification,
  CORE_PURE_PATH,
  extractElementNameFromPath,
  extractPackagePathFromPath,
  PRIMITIVE_TYPE,
  V1_AppliedFunction,
  V1_AppliedProperty,
  V1_CBoolean,
  V1_CDateTime,
  V1_CDecimal,
  V1_CFloat,
  V1_CInteger,
  V1_ClassInstance,
  V1_ClassInstanceType,
  V1_CLatestDate,
  V1_Collection,
  V1_ColSpec,
  V1_ColSpecArray,
  V1_createGenericTypeWithElementPath,
  V1_createGenericTypeWithRawType,
  V1_createRelationType,
  V1_createRelationTypeColumn,
  V1_CStrictDate,
  V1_CStrictTime,
  V1_CString,
  V1_Enumeration,
  V1_EnumValue,
  V1_GenericTypeInstance,
  V1_Lambda,
  V1_Multiplicity,
  V1_PackageableElementPtr,
  V1_PackageableType,
  V1_Variable,
} from '@finos/legend-graph';
import {
  type DataCubeSnapshotFilterCondition,
  type DataCubeSnapshotFilter,
  type DataCubeSnapshot,
} from './DataCubeSnapshot.js';
import { _findCol, type DataCubeColumn } from './model/DataCubeColumn.js';
import {
  guaranteeNonNullable,
  guaranteeIsString,
  guaranteeIsBoolean,
  guaranteeIsNumber,
  UnsupportedOperationError,
} from '@finos/legend-shared';
import {
  DataCubeFunction,
  DEFAULT_LAMBDA_VARIABLE_NAME,
  DataCubeQueryFilterGroupOperator,
  type DataCubeOperationValue,
  DataCubeOperationAdvancedValueType,
  DataCubeColumnKind,
  type DataCubeQueryFunctionMap,
  isPivotResultColumnName,
  getPivotResultColumnBaseColumnName,
  DEFAULT_ROOT_AGGREGATION_COLUMN_VALUE,
  DataCubeQueryFilterOperator,
} from './DataCubeQueryEngine.js';
import type { DataCubeQueryFilterOperation } from './filter/DataCubeQueryFilterOperation.js';
import type { DataCubeQueryAggregateOperation } from './aggregation/DataCubeQueryAggregateOperation.js';
import {
  DataCubeColumnConfiguration,
  type DataCubeConfiguration,
} from './model/DataCubeConfiguration.js';
import type { DataCubeDimensionalGroupByNode } from '../view/grid/DataCubeGridDimensionalTree.js';

// --------------------------------- UTILITIES ---------------------------------

export function _var() {
  const variable = new V1_Variable();
  // NOTE: we simplify processing logic by forcing all variable names to default value, i.e. x
  variable.name = DEFAULT_LAMBDA_VARIABLE_NAME;
  return variable;
}

export function _property(name: string, parameters?: V1_ValueSpecification[]) {
  const property = new V1_AppliedProperty();
  property.property = name;
  property.parameters = parameters ?? [_var()];
  return property;
}

export function _lambda(
  parameters: V1_Variable[],
  body: V1_ValueSpecification[],
) {
  const lambda = new V1_Lambda();
  lambda.parameters = parameters;
  lambda.body = body;
  return lambda;
}

// NOTE: the list of auto-import are kept in `m3.pure` file in `finos/legend-pure`,
// this includes a more extensive list of packges which contain native functions, classes, etc.
// See https://github.com/finos/legend-pure/blob/master/legend-pure-core/legend-pure-m3-core/src/main/resources/platform/pure/grammar/m3.pure
const PURE_AUTO_IMPORT_PACKAGE_PATHS = [
  'meta::pure::metamodel',
  'meta::pure::metamodel::type',
  'meta::pure::metamodel::type::generics',
  'meta::pure::metamodel::relationship',
  'meta::pure::metamodel::valuespecification',
  'meta::pure::metamodel::multiplicity',
  'meta::pure::metamodel::function',
  'meta::pure::metamodel::function::property',
  'meta::pure::metamodel::extension',
  'meta::pure::metamodel::import',
  'meta::pure::functions::date',
  'meta::pure::functions::string',
  'meta::pure::functions::collection',
  'meta::pure::functions::meta',
  'meta::pure::functions::constraints',
  'meta::pure::functions::lang',
  'meta::pure::functions::boolean',
  'meta::pure::functions::tools',
  'meta::pure::functions::relation',
  'meta::pure::functions::io',
  'meta::pure::functions::math',
  'meta::pure::functions::asserts',
  'meta::pure::functions::test',
  'meta::pure::functions::multiplicity',
  'meta::pure::router',
  'meta::pure::service',
  'meta::pure::tds',
  'meta::pure::tools',
  'meta::pure::profiles',
];

export function _functionName(
  funcNameOrPath: string,
  options?: { useFullFunctionPath?: boolean },
) {
  if (options?.useFullFunctionPath) {
    return funcNameOrPath;
  }

  const funcPakagePath = extractPackagePathFromPath(funcNameOrPath);
  if (
    funcPakagePath &&
    PURE_AUTO_IMPORT_PACKAGE_PATHS.includes(funcPakagePath)
  ) {
    return extractElementNameFromPath(funcNameOrPath);
  }
  return funcNameOrPath;
}

export function _function(
  functionName: string,
  parameters: V1_ValueSpecification[],
  options?: {
    useFullFunctionPath?: boolean;
  },
) {
  const func = new V1_AppliedFunction();
  func.function = _functionName(functionName, options);
  func.parameters = parameters;
  return func;
}

export function _collection(values: V1_ValueSpecification[]) {
  const collection = new V1_Collection();
  collection.multiplicity = new V1_Multiplicity(values.length, values.length);
  collection.values = values;
  return collection;
}

export function _primitiveValue(
  type: string,
  value: unknown,
  coerceType?: boolean,
): V1_PrimitiveValueSpecification {
  const _val = <T extends V1_PrimitiveValueSpecification & { value: unknown }>(
    primitiveValue: T,
    val: unknown,
  ): T => {
    primitiveValue.value = val;
    return primitiveValue;
  };
  switch (type) {
    case PRIMITIVE_TYPE.STRING:
      return _val(new V1_CString(), guaranteeIsString(value));
    case PRIMITIVE_TYPE.BOOLEAN:
      return _val(
        new V1_CBoolean(),
        guaranteeIsBoolean(
          coerceType
            ? value === 'true'
              ? true
              : value === 'false'
                ? false
                : value
            : value,
        ),
      );
    case PRIMITIVE_TYPE.NUMBER:
    case PRIMITIVE_TYPE.DECIMAL:
      return _val(
        new V1_CDecimal(),
        guaranteeIsNumber(
          coerceType ? parseFloat(guaranteeIsString(value)) : value,
        ),
      );
    case PRIMITIVE_TYPE.INTEGER:
      return _val(
        new V1_CInteger(),
        guaranteeIsNumber(
          coerceType ? parseInt(guaranteeIsString(value)) : value,
        ),
      );
    case PRIMITIVE_TYPE.FLOAT:
      return _val(
        new V1_CFloat(),
        guaranteeIsNumber(
          coerceType ? parseFloat(guaranteeIsString(value)) : value,
        ),
      );
    case PRIMITIVE_TYPE.DATE:
    case PRIMITIVE_TYPE.STRICTDATE:
      return _val(new V1_CStrictDate(), guaranteeIsString(value));
    case PRIMITIVE_TYPE.DATETIME:
      return _val(new V1_CDateTime(), guaranteeIsString(value));
    case PRIMITIVE_TYPE.STRICTTIME:
      return _val(new V1_CStrictTime(), guaranteeIsString(value));
    case PRIMITIVE_TYPE.LATESTDATE:
      return new V1_CLatestDate();
    default:
      throw new UnsupportedOperationError(
        `Can't build primitive value instance for unsupported type '${type}'`,
      );
  }
}

export function _enumValue(value: string): V1_EnumValue {
  const enumValue = new V1_EnumValue();
  enumValue.value = value;
  return enumValue;
}

export function _enumeration(
  enumerationPackage: string,
  enumerationName: string,
  values: V1_EnumValue[],
): V1_Enumeration {
  const enumeration = new V1_Enumeration();
  enumeration.package = enumerationPackage;
  enumeration.name = enumerationName;
  enumeration.values = values;
  return enumeration;
}

export function _elementPtr(fullPath: string) {
  const ptr = new V1_PackageableElementPtr();
  ptr.fullPath = fullPath;
  return ptr;
}

export function _type(fullPath: string) {
  const type = new V1_PackageableType();
  type.fullPath = fullPath;
  return type;
}

function _classInstance(type: string, value: unknown) {
  const instance = new V1_ClassInstance();
  instance.type = type;
  instance.value = value;
  return instance;
}

export function _colSpec(
  name: string,
  function1?: V1_Lambda | undefined,
  function2?: V1_Lambda | undefined,
  type?: string | undefined,
) {
  const colSpec = new V1_ColSpec();
  colSpec.name = name;
  colSpec.function1 = function1;
  colSpec.function2 = function2;
  colSpec.type = type;
  return colSpec;
}

export function _value(value: DataCubeOperationValue) {
  switch (value.type) {
    case PRIMITIVE_TYPE.STRING:
    case PRIMITIVE_TYPE.BOOLEAN:
    case PRIMITIVE_TYPE.NUMBER:
    case PRIMITIVE_TYPE.DECIMAL:
    case PRIMITIVE_TYPE.INTEGER:
    case PRIMITIVE_TYPE.FLOAT:
    case PRIMITIVE_TYPE.DATE:
    case PRIMITIVE_TYPE.DATETIME:
    case PRIMITIVE_TYPE.STRICTDATE:
    case PRIMITIVE_TYPE.STRICTTIME: {
      if (Array.isArray(value.value)) {
        return _collection(
          value.value.map((val) => _primitiveValue(value.type, val)),
        );
      }
      return _primitiveValue(value.type, value.value);
    }
    case DataCubeOperationAdvancedValueType.COLUMN:
      return _property(guaranteeIsString(value.value));
    default:
      throw new UnsupportedOperationError(
        `Can't build value instance for unsupported type '${value.type}'`,
      );
  }
}

export function _not(fn: V1_AppliedFunction) {
  return _function(_functionName(DataCubeFunction.NOT), [fn]);
}

export function _col(
  name: string,
  function1?: V1_Lambda | undefined,
  function2?: V1_Lambda | undefined,
) {
  return _classInstance(
    V1_ClassInstanceType.COL_SPEC,
    _colSpec(name, function1, function2),
  );
}

export function _cols(colSpecs: V1_ColSpec[]) {
  const colSpecArray = new V1_ColSpecArray();
  colSpecArray.colSpecs = colSpecs;
  return _classInstance(V1_ClassInstanceType.COL_SPEC_ARRAY, colSpecArray);
}

// --------------------------------- BUILDING BLOCKS ---------------------------------

export function _functionCompositionProcessor(
  sequence: V1_AppliedFunction[],
  funcMap: DataCubeQueryFunctionMap,
) {
  return (
    key: keyof DataCubeQueryFunctionMap,
    data: V1_AppliedFunction | V1_AppliedFunction[],
  ) => {
    switch (key) {
      case 'leafExtend':
      case 'groupExtend': {
        if (Array.isArray(data)) {
          data.forEach((func) => sequence.push(func));
          funcMap[key] = data;
        }
        break;
      }
      default: {
        funcMap[key] = data as V1_AppliedFunction;
        sequence.push(data as V1_AppliedFunction);
      }
    }
  };
}

export function _functionCompositionUnProcessor(
  sequence: V1_AppliedFunction[],
  funcMap: DataCubeQueryFunctionMap,
) {
  return (key: keyof DataCubeQueryFunctionMap) => {
    const data = funcMap[key];
    if (data) {
      if (Array.isArray(data)) {
        data.forEach((func) => sequence.splice(sequence.indexOf(func), 1));
      } else {
        sequence.splice(sequence.indexOf(data), 1);
      }
      funcMap[key] = undefined;
    }
  };
}

export function _selectFunction(columns: DataCubeColumn[]) {
  return _function(DataCubeFunction.SELECT, [
    _cols(columns.map((col) => _colSpec(col.name))),
  ]);
}

export function _synthesizeMinimalSourceQuery(columns: DataCubeColumn[]) {
  return _function(DataCubeFunction.CAST, [
    _primitiveValue(PRIMITIVE_TYPE.STRING, ''),
    _castCols(columns),
  ]);
}

export function _extendRootAggregation(columnName: string) {
  return _function(DataCubeFunction.EXTEND, [
    _col(
      columnName,
      _lambda(
        [_var()],
        [
          _primitiveValue(
            PRIMITIVE_TYPE.STRING,
            DEFAULT_ROOT_AGGREGATION_COLUMN_VALUE,
          ),
        ],
      ),
    ),
  ]);
}

// NOTE: this is the column name used for the dummy count() aggregate
// when no aggregate is specified in groupBy() or pivot()
const INTERNAL__FILLER_COUNT_AGG_COLUMN_NAME =
  'INTERNAL__filler_count_agg_column';
// if no aggregates are specified, add a dummy count() aggregate to satisfy compiler
function _fixEmptyAggCols(aggCols: V1_ColSpec[]) {
  const variable = _var();
  return aggCols.length
    ? aggCols
    : [
        _colSpec(
          INTERNAL__FILLER_COUNT_AGG_COLUMN_NAME,
          _lambda([variable], [variable]),
          _lambda([variable], [_function(DataCubeFunction.COUNT, [variable])]),
        ),
      ];
}

export function _aggCol_base(
  column: DataCubeColumn,
  func: string,
  paramterValues?: DataCubeOperationValue[] | undefined,
) {
  const variable = _var();
  return _colSpec(
    column.name,
    _lambda([variable], [_property(column.name)]),
    _lambda(
      [variable],
      [
        _function(_functionName(func), [
          variable,
          ...(paramterValues ?? []).map((value) => _value(value)),
        ]),
      ],
    ),
  );
}

export function _pivotAggCols(
  pivotColumns: DataCubeColumn[],
  snapshot: DataCubeSnapshot,
  configuration: DataCubeConfiguration,
  aggregateOperations: DataCubeQueryAggregateOperation[],
) {
  const aggColumns = configuration.columns.filter(
    (column) =>
      column.isSelected &&
      // unlike groupBy, pivot aggreation on dimension columns (e.g. unique values aggregator)
      // are not helpful and therefore excluded
      column.kind === DataCubeColumnKind.MEASURE &&
      !_findCol(pivotColumns, column.name) &&
      !column.excludedFromPivot &&
      !_findCol(snapshot.data.groupExtendedColumns, column.name),
  );
  return _fixEmptyAggCols(
    aggColumns.map((agg) => {
      const operation = aggregateOperations.find(
        (op) => op.operator === agg.aggregateOperator,
      );
      const aggCol = operation?.buildAggregateColumnExpression(agg);
      if (!aggCol) {
        throw new UnsupportedOperationError(
          `Can't build aggregate column for unsupported operator '${agg.aggregateOperator}'`,
        );
      }
      return aggCol;
    }),
  );
}

export function _castCols(columns: DataCubeColumn[]) {
  const genericTypeInstance = new V1_GenericTypeInstance();
  genericTypeInstance.genericType = V1_createGenericTypeWithElementPath(
    CORE_PURE_PATH.RELATION,
  );
  genericTypeInstance.genericType.typeArguments = [
    V1_createGenericTypeWithRawType(
      V1_createRelationType(
        columns.map((col) => V1_createRelationTypeColumn(col.name, col.type)),
      ),
    ),
  ];
  return genericTypeInstance;
}

export function _groupByAggCols(
  groupByColumns: DataCubeColumn[],
  snapshot: DataCubeSnapshot,
  configuration: DataCubeConfiguration,
  aggregateOperations: DataCubeQueryAggregateOperation[],
) {
  const pivot = snapshot.data.pivot;

  if (!pivot) {
    // NOTE: reference off column configuration so we follow the order of columns
    // established in columns selector
    const aggColumns = configuration.columns.filter(
      (column) =>
        column.isSelected &&
        !_findCol(groupByColumns, column.name) &&
        !_findCol(snapshot.data.groupExtendedColumns, column.name),
    );
    return _fixEmptyAggCols(
      aggColumns.map((agg) => {
        const operation = aggregateOperations.find(
          (op) => op.operator === agg.aggregateOperator,
        );
        const aggCol = operation?.buildAggregateColumnExpression(agg);
        if (!aggCol) {
          throw new UnsupportedOperationError(
            `Can't build aggregate column for unsupported operator '${agg.aggregateOperator}'`,
          );
        }
        return aggCol;
      }),
    );
  }

  const pivotResultColumns = pivot.castColumns.filter((col) =>
    isPivotResultColumnName(col.name),
  );
  const pivotGroupByColumns = pivot.castColumns.filter(
    (col) => !isPivotResultColumnName(col.name),
  );
  return _fixEmptyAggCols([
    // for pivot result columns, resolve the base aggregate column to get aggregate configuration
    ...pivotResultColumns
      .map((column) => {
        const baseAggColName = getPivotResultColumnBaseColumnName(column.name);
        return {
          ...column,
          matchingColumnConfiguration: _findCol(
            configuration.columns,
            baseAggColName,
          ),
        };
      })
      .filter((column) => column.matchingColumnConfiguration)
      .map((column) => {
        const columnConfiguration =
          DataCubeColumnConfiguration.serialization.fromJson(
            guaranteeNonNullable(
              column.matchingColumnConfiguration,
            ).serialize(),
          );
        columnConfiguration.name = column.name;
        const operation = aggregateOperations.find(
          (op) => op.operator === columnConfiguration.aggregateOperator,
        );
        const aggCol =
          operation?.buildAggregateColumnExpression(columnConfiguration);
        if (!aggCol) {
          throw new UnsupportedOperationError(
            `Can't build aggregate column for unsupported operator '${columnConfiguration.aggregateOperator}'`,
          );
        }
        return aggCol;
      }),
    // these are the columns which are available for groupBy but not selected for groupBy
    // operation, they would be aggregated as well
    ...pivotGroupByColumns
      .filter((column) => !_findCol(groupByColumns, column.name))
      .map((column) => {
        const columnConfiguration = guaranteeNonNullable(
          _findCol(configuration.columns, column.name),
        );
        const operation = aggregateOperations.find(
          (op) => op.operator === columnConfiguration.aggregateOperator,
        );
        const aggCol =
          operation?.buildAggregateColumnExpression(columnConfiguration);
        if (!aggCol) {
          throw new UnsupportedOperationError(
            `Can't build aggregate column for unsupported operator '${columnConfiguration.aggregateOperator}'`,
          );
        }
        return aggCol;
      }),
  ]);
}

export function _filter(
  filter: DataCubeSnapshotFilter | DataCubeSnapshotFilterCondition,
  filterOperations: DataCubeQueryFilterOperation[],
) {
  if ('groupOperator' in filter) {
    const filterGroup = filter;
    const groupOperation =
      filterGroup.groupOperator === DataCubeQueryFilterGroupOperator.AND
        ? DataCubeFunction.AND
        : DataCubeFunction.OR;
    let conditions: V1_AppliedFunction[] = [];
    filterGroup.conditions.forEach((condition) => {
      conditions.push(_filter(condition, filterOperations));
      // NOTE: a group operation (and/or) function can only have 2 parameters, so we
      // have to breakdown the group operation into nested group functions
      if (conditions.length === 2) {
        conditions = [_function(groupOperation, conditions)];
      }
    });
    const groupCondition = guaranteeNonNullable(conditions[0]);
    return filterGroup.not ? _not(groupCondition) : groupCondition;
  } else {
    const filterCondition = filter;
    const operation = filterOperations.find(
      (op) => op.operator === filterCondition.operator,
    );
    const condition = operation?.buildConditionExpression(filterCondition);
    if (!condition) {
      throw new UnsupportedOperationError(
        `Can't build filter condition expression for unsupported operator '${filterCondition.operator}'`,
      );
    }
    return filterCondition.not ? _not(condition) : condition;
  }
}

export function _flattenFilterSnapshot(
  groupByNodes: DataCubeDimensionalGroupByNode[],
): DataCubeSnapshotFilter {
  const filterConditions = groupByNodes.map((node) => {
    return {
      name: node.column,
      type: 'String', // Assuming all filters are strings — update if needed
      operator: DataCubeQueryFilterOperator.EQUAL,
      value: {
        type: 'String',
        value: node.filter,
      } satisfies DataCubeOperationValue,
    } satisfies DataCubeSnapshotFilterCondition;
  });
  return {
    groupOperator: DataCubeQueryFilterGroupOperator.AND,
    conditions: filterConditions,
  } satisfies DataCubeSnapshotFilter;
}