/*
 * Copyright (C) 2019 StApps
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation, version 3.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program. If not, see <https://www.gnu.org/licenses/>.
 */
import {Logger} from '@openstapps/logger';
import {
  ArrayType,
  ConditionalType,
  DeclarationReflection,
  IntrinsicType,
  ProjectReflection,
  QueryType,
  ReferenceType,
  ReflectionKind,
  ReflectionType,
  StringLiteralType,
  Type,
  TypeOperatorType,
  TypeParameterType,
  UnionType,
} from 'typedoc/dist/lib/models';
import {getFullTypeName} from '../common';
import {LightweightClassDefinition} from './model/lightweight-class-definition';
import {LightweightDefinition} from './model/lightweight-definition';
import {LightweightEnumDefinition} from './model/lightweight-enum-definition';
import {LightweightProperty} from './model/lightweight-property';
import {LightweightType} from './model/lightweight-type';

/**
 * Reads the reflection model from typedoc and converts it into a flatter, easier to handle model
 *
 * @param srcPath Path to source file directory
 */
export function readDefinitions(projectReflection: ProjectReflection): LightweightDefinition[] {

  const definitions: LightweightDefinition[] = [];

  // define known types and categorize them
  const enumLike: string[] = ['Type alias', 'Enumeration'];
  const classLike: string[] = ['Class', 'Interface'];
  const unused: string[] = ['Function', 'Object literal', 'Variable'];

  // children need to be not undefined, if they are return empty
  if (typeof projectReflection.children === 'undefined') {
    return [];
  }

  for (const module of projectReflection.children) {
    if (Array.isArray(module.children) && module.children.length > 0) {
      // iterate over class and enum declarations
      for (const type of module.children) {
        // only if kindString is set
        if (typeof type.kindString !== 'undefined') {
          // check if declaration is enum
          if (classLike.includes(type.kindString)) {
            definitions.push(readAsClassDefinition(type));
          } else if (enumLike.includes(type.kindString)) {
            definitions.push(readAsEnumDefinition(type));
          } else if (unused.includes(type.kindString)) {
            Logger.info(`Unconverted ${type.kindString} : ${type.name}`);
          } else {
            Logger.log(
              `Uncaught declaration type (${type.kindString}) : ${type.name}`,
            );
          }
        }
      }
    }
  }

  return definitions;
}

/**
 * Transforms the declaration into a `LightweightClassDefinition`
 *
 * @param declaration declaration
 */
export function readAsEnumDefinition(
  declaration: DeclarationReflection,
): LightweightEnumDefinition {
  // init enum definition
  const enumDefinition: LightweightEnumDefinition = new LightweightEnumDefinition(
    declaration.name,
  );

  // get enum values according to type
  if (declaration.kindString === 'Enumeration' && typeof declaration.children !== 'undefined') {
    // standard enumeration
    for (const child of declaration.children) {
      if (child.kindString === 'Enumeration member') {
        let value = child.name;
        if (typeof child.defaultValue !== 'undefined') {
          value = `${value} = ${child.defaultValue}`;
        }
        enumDefinition.values.push(value);
      } else {
        Logger.log(
          "Every enumeration member should be an 'EnumerationMemberType'",
        );
      }
    }
  } else if (
    declaration.kindString === 'Type alias' &&
    typeof declaration.type !== 'undefined'
  ) {
    // enum like declaration
    try {
      const a = readTypeInformation(declaration.type);
      enumDefinition.values = enumDefinition.values.concat(
        getTypeInformation(a),
      );
    } catch (e) {
      Logger.warn(
        `Could not read the light type for ${declaration.name}. ${e}`,
      );
    }
  }

  return enumDefinition;
}

/**
 * Used for enumrations to get the type value
 */
function getTypeInformation(type: LightweightType): string[] {
  const values: string[] = [];
  if (!type.hasTypeInformation) {
    for (const specificType of type.specificationTypes) {
      for (const value of getTypeInformation(specificType)) {
        values.push(value);
      }
    }
  } else {
    values.push(type.name);
  }

  return values;
}

/**
 * Transforms the declaration into a `LightweightClassDefinition`
 *
 * @param declaration declaration
 */
export function readAsClassDefinition(
  declaration: DeclarationReflection,
): LightweightClassDefinition {
  let type = typeof declaration.kindString !== 'undefined' ? declaration.kindString.toLowerCase() : '';
  type = (declaration.flags.isAbstract ? 'abstract ' : '') + type;

  const classDefinition: LightweightClassDefinition = new LightweightClassDefinition(
    declaration.name,
    type,
  );

  // get generic types
  if (typeof declaration.typeParameters !== 'undefined') {
    const typeParameters: string[] = [];
    declaration.typeParameters.forEach((typeParameter) =>
      typeParameters.push(typeParameter.name),
    );
    classDefinition.typeParameters = typeParameters;
  }

  // extracts extended types of the declaration
  if (typeof declaration.extendedTypes !== 'undefined') {
    for (const extType of declaration.extendedTypes) {
      classDefinition.extendedDefinitions.push((extType as ReferenceType).name);
    }
  }

  // extracts implemented types of the declaration
  // HINT: typedoc automatically adds inherited interfaces to the declaration directly
  if (typeof declaration.implementedTypes !== 'undefined') {
    for (const implType of declaration.implementedTypes) {
      classDefinition.implementedDefinitions.push(
        (implType as ReferenceType).name,
      );
    }
  }

  if (typeof declaration.children !== 'undefined') {
    for (const child of declaration.getChildrenByKind(
      ReflectionKind.Property,
    )) {
      try {
        if (typeof child.type === 'undefined') {
          throw new Error();
        }

        const myType: LightweightType = readTypeInformation(child.type);
        const property = new LightweightProperty(child.name, myType);

        const flags = child.flags;
        if (flags.isOptional !== undefined) {
          property.optional = flags.isOptional as boolean;
          property.inherited = !(
            child.inheritedFrom === undefined || child.inheritedFrom === null
          );
        }
        classDefinition.properties.push(property);
      } catch (e) {
        Logger.warn(e);
      }
    }
  }

  return classDefinition;
}

/**
 * The structure of reflection type has a huge overhead
 * This method and all submethods will convert these types in easier to process Types
 *
 * @param declarationType Type to be converted
 */
function readTypeInformation(declarationType: Type): LightweightType {
  if (declarationType instanceof ReflectionType) {
    return readAsReflectionType(declarationType);
  }
  if (declarationType instanceof TypeOperatorType) {
    return readAsTypeOperatorType(declarationType);
  }
  if (declarationType instanceof TypeParameterType) {
    return readAsTypeParameterType(declarationType);
  }
  if (declarationType instanceof IntrinsicType) {
    return readAsIntrinsicType(declarationType);
  }
  if (declarationType instanceof StringLiteralType) {
    return readAsStringLiteralType(declarationType);
  }
  if (declarationType instanceof ReferenceType) {
    return readAsReferenceType(declarationType);
  }
  if (declarationType instanceof ArrayType) {
    return readAsArrayType(declarationType);
  }
  if (declarationType instanceof UnionType) {
    return readAsUnionType(declarationType);
  }
  if (declarationType instanceof QueryType) {
    return readAsQueryType(declarationType);
  }
  if (declarationType instanceof ConditionalType) {
    return readAsConditionalType(declarationType);
  }

  throw new Error(`Could not read type ${declarationType.type}`);
}

/**
 * Conversion method for ConditionalTypes
 *
 * @param _type Type to be converted
 */
function readAsConditionalType(_type: ConditionalType): LightweightType {
  const returnType: LightweightType = new LightweightType();

  returnType.specificationTypes = [];
  returnType.name = getFullTypeName(returnType);
  returnType.isUnion = true;

  return returnType;
}

/**
 * Conversion method for QueryTypes
 *
 * @param type Type to be converted
 */
function readAsQueryType(type: QueryType): LightweightType {
  const out = readAsReferenceType(type.queryType);
  out.isReference = true;

  return out;
}

/**
 * Conversion method for IntrinsicType's
 *
 * e.g. remainingAttendeeCapacity?: number;
 *
 * @param type Type to be converted
 */
function readAsIntrinsicType(type: IntrinsicType): LightweightType {
  const easyType: LightweightType = new LightweightType();
  easyType.name = type.name;
  easyType.isPrimitive = true;
  easyType.hasTypeInformation = true;

  return easyType;
}

/**
 * Conversion method for StringLiteralType's
 *
 * e.g. inputType: 'multipleChoice';
 *
 * @param type Type to be converted
 */
function readAsStringLiteralType(type: StringLiteralType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  returnType.name = type.value;
  returnType.isLiteral = true;
  returnType.hasTypeInformation = true;

  return returnType;
}

/**
 * Conversion method for ReferenceType's
 *
 * Everything that is a user or API designed definition and not a primitive type or core-language feature.
 *
 * e.g. publishers?: Array<SCPersonWithoutReferences | SCOrganizationWithoutReferences>;
 *
 * Array, SCPersonWithoutReferences and SCOrganizationWithoutReferences will be recognized as reference types!
 *
 * @param type Type to be converted
 */
function readAsReferenceType(type: ReferenceType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  returnType.name = type.name;

  if (type.typeArguments !== undefined && type.typeArguments.length > 0) {
    const typeArguments: LightweightType[] = [];

    for (const value of type.typeArguments) {
      typeArguments.push(readTypeInformation(value));
    }

    returnType.isTyped = true;
    returnType.genericsTypes = typeArguments;
  }

  if (type.reflection !== undefined && type.reflection !== null) {
    const tempTypeReflection = type.reflection as DeclarationReflection;
    // interfaces and classes in a type are a sink, since their declaration are defined elsewhere
    if (
      typeof tempTypeReflection.kindString !== 'undefined' &&
      ['Interface', 'Class', 'Enumeration', 'Type alias'].includes(
        tempTypeReflection.kindString)) {
      returnType.isReference = true;
    }
  }

  returnType.hasTypeInformation = true;

  return returnType;
}

/**
 * Conversion method for ArrayType's
 *
 * The actual type of the array is stored in the first element of specificationTypes.
 *
 * e.g. articleBody?: string[];
 *
 * @param type Type to be converted
 */
function readAsArrayType(type: ArrayType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  const typeOfArray: LightweightType = readTypeInformation(type.elementType);
  returnType.name = getFullTypeName(typeOfArray);
  returnType.specificationTypes = [typeOfArray];
  returnType.isArray = true;

  return returnType;
}

/**
 * Conversion method for UnionType's
 *
 * The Union-LightType store the single types of the union inside a
 * separate LightType inside specificationTypes.
 *
 * e.g. maintainer?: SCPerson | SCOrganization;
 *
 * @param type Type to be converted
 */
function readAsUnionType(type: UnionType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  const typesOfUnion: LightweightType[] = [];
  for (const value of type.types) {
    typesOfUnion.push(readTypeInformation(value));
  }
  returnType.specificationTypes = typesOfUnion;
  returnType.name = getFullTypeName(returnType);
  returnType.isUnion = true;

  return returnType;
}

/**
 * Conversion method for ReflectionType's
 *
 * The explicit type is not contained in reflection!
 * It might be possible to get the structure of type by reading tempType.decoration.children,
 * but this structure is currently not supported in the data-model.
 *
 * e.g. categorySpecificValues?: { [s: string]: U };
 *
 * @param type Type to be converted
 */
function readAsReflectionType(type: ReflectionType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  if (typeof type.declaration.sources !== 'undefined') {
    const src = type.declaration.sources[0];
    Logger.warn(
      `${src.line} : ${src.fileName}: Reflection Type not recognized. Refactoring to explicit class is advised.`,
    );
  }
  returnType.name = 'object';
  returnType.isReflection = true;

  return returnType;
}

/**
 * Conversion method for TypeOperatorType's
 *
 * This type is similar to reflection, that the actual type can only be evaluated at runtime.
 *
 * e.g. universityRole: keyof SCSportCoursePriceGroup;
 *
 * @param type Type to be converted
 */
function readAsTypeOperatorType(type: TypeOperatorType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  const typeOf: LightweightType = readTypeInformation(type.target);
  returnType.name = `keyof ${getFullTypeName(typeOf)}`;
  returnType.specificationTypes = [typeOf];
  // can't be traced deeper! so might as well be a primitive
  returnType.isPrimitive = true;
  returnType.hasTypeInformation = true;

  return returnType;
}

/**
 * Conversion method for TypeParameterType's
 *
 * Should only be called in generic classes/interfaces, when a property is
 * referencing the generic-type.
 *
 * e.g. prices?: T;
 *
 * Does not match on Arrays of the generic type. Those will be matched with ArrayType.
 *
 * @param type Needs to be a TypeParameterType
 */
function readAsTypeParameterType(type: TypeParameterType): LightweightType {
  const returnType: LightweightType = new LightweightType();
  returnType.name = type.name;
  returnType.isTypeParameter = true;
  returnType.hasTypeInformation = true;

  return returnType;
}