typescript-json-schema/typescript-json-schema.ts

import * as glob from "glob";
import * as stringify from "json-stable-stringify";
import * as path from "path";
import * as ts from "typescript";
export { Program, CompilerOptions, Symbol } from "typescript";


const vm = require("vm");

const REGEX_FILE_NAME = /".*"\./;
const REGEX_TSCONFIG_NAME = /^.*\.json$/;
const REGEX_TJS_JSDOC = /^-([\w]+)\s+(\S|\S[\s\S]*\S)\s*$/g;

export function getDefaultArgs(): Args {
    return {
        ref: true,
        aliasRef: false,
        topRef: false,
        titles: false,
        defaultProps: false,
        noExtraProps: false,
        propOrder: false,
        typeOfKeyword: false,
        required: false,
        strictNullChecks: false,
        ignoreErrors: false,
        out: "",
        validationKeywords: [],
        include: [],
        excludePrivate: false,
        uniqueNames: false,
    };
}

export type ValidationKeywords = {
  [prop: string]: boolean
};

export type Args = {
    ref: boolean;
    aliasRef: boolean;
    topRef: boolean;
    titles: boolean;
    defaultProps: boolean;
    noExtraProps: boolean;
    propOrder: boolean;
    typeOfKeyword: boolean;
    required: boolean;
    strictNullChecks: boolean;
    ignoreErrors: boolean;
    out: string;
    validationKeywords: string[];
    include: string[];
    excludePrivate: boolean;
    uniqueNames: boolean;
};

export type PartialArgs = Partial<Args>;

export type PrimitiveType = number | boolean | string | null;

export type Definition = {
    $ref?: string,
    $schema?: string,
    description?: string,
    allOf?: Definition[],
    oneOf?: Definition[],
    anyOf?: Definition[],
    title?: string,
    type?: string | string[],
    definitions?: {[key: string]: any},
    format?: string,
    items?: Definition | Definition[],
    minItems?: number,
    additionalItems?: {
        anyOf: Definition[]
    },
    enum?: PrimitiveType[] | Definition[],
    default?: PrimitiveType | Object,
    additionalProperties?: Definition | boolean,
    required?: string[],
    propertyOrder?: string[],
    properties?: {[key: string]: any},
    defaultProperties?: string[],

    typeof?: "function"
};

export type SymbolRef = {
  name: string;
  typeName: string;
  fullyQualifiedName: string;
  symbol: ts.Symbol;
};

function extend(target: any, ..._: any[]) {
    if (target == null) { // TypeError if undefined or null
      throw new TypeError("Cannot convert undefined or null to object");
    }

    const to = Object(target);

    for (var index = 1; index < arguments.length; index++) {
      const nextSource = arguments[index];

      if (nextSource != null) { // Skip over if undefined or null
        for (const nextKey in nextSource) {
          // Avoid bugs when hasOwnProperty is shadowed
          if (Object.prototype.hasOwnProperty.call(nextSource, nextKey)) {
            to[nextKey] = nextSource[nextKey];
          }
        }
      }
    }
    return to;
}

function unique(arr: string[]): string[] {
    const temp = {};
    for (const e of arr) {
      temp[e] = true;
    }
    const r: string[] = [];
    for (const k in temp) {
      // Avoid bugs when hasOwnProperty is shadowed
      if (Object.prototype.hasOwnProperty.call(temp, k)) {
        r.push(k);
      }
    }
    return r;
}

/**
 * Try to parse a value and returns the string if it fails.
 */
function parseValue(value: string) {
    try {
        return JSON.parse(value);
    } catch (error) {
        return value;
    }
}

function extractLiteralValue(typ: ts.Type): PrimitiveType | undefined {
    let str = (<ts.LiteralType>typ).value;
    if (str === undefined) {
        str = (typ as any).text;
    }
    if (typ.flags & ts.TypeFlags.StringLiteral) {
        return str;
    } else if (typ.flags & ts.TypeFlags.BooleanLiteral) {
        return (typ as any).intrinsicName === "true";
    } else if (typ.flags & ts.TypeFlags.EnumLiteral) {
        // or .text for old TS
        const num = parseFloat(str as string);
        return isNaN(num) ? str : num;
    } else if (typ.flags & ts.TypeFlags.NumberLiteral) {
        return parseFloat(str as string);
    }
    return undefined;
}

/**
 * Checks whether a type is a tuple type.
 */
function resolveTupleType(propertyType: ts.Type): ts.TupleTypeNode|null {
    if (!propertyType.getSymbol() && (propertyType.getFlags() & ts.TypeFlags.Object && (<ts.ObjectType>propertyType).objectFlags & ts.ObjectFlags.Reference)) {
        return (propertyType as ts.TypeReference).target as any;
    }
    if (!(propertyType.getFlags() & ts.TypeFlags.Object && (<ts.ObjectType>propertyType).objectFlags & ts.ObjectFlags.Tuple)) {
        return null;
    }
    return propertyType as any;
}

const simpleTypesAllowedProperties = {
    type: true,
    description: true
};

function addSimpleType(def: Definition, type: string) {
    for (const k in def) {
        if (!simpleTypesAllowedProperties[k]) {
            return false;
        }
    }

    if (!def.type) {
        def.type = type;
    } else if (typeof def.type !== "string") {
        if (!(<Object[]>def.type).every((val) => { return typeof val === "string"; })) {
            return false;
        }

        if (def.type.indexOf("null") === -1) {
            def.type.push("null");
        }
    } else {
        if (typeof def.type !== "string") {
            return false;
        }

        if (def.type !== "null") {
            def.type = [ def.type, "null" ];
        }
    }
    return true;
}

function makeNullable(def: Definition) {
    if (!addSimpleType(def, "null")) {
        const union = def.oneOf || def.anyOf;
        if (union) {
            union.push({ type: "null" });
        } else {
            const subdef = {};
            for (var k in def) {
                if (def.hasOwnProperty(k)) {
                    subdef[k] = def[k];
                    delete def[k];
                }
            }
            def.anyOf = [ subdef, { type: "null" } ];
        }
    }
    return def;
}

/**
 * JSDoc keywords that should be used to annotate the JSON schema.
 *
 * Many of these validation keywords are defined here: http://json-schema.org/latest/json-schema-validation.html
 */
const validationKeywords = {
    multipleOf: true,               // 6.1.
    maximum: true,                  // 6.2.
    exclusiveMaximum: true,         // 6.3.
    minimum: true,                  // 6.4.
    exclusiveMinimum: true,         // 6.5.
    maxLength: true,                // 6.6.
    minLength: true,                // 6.7.
    pattern: true,                  // 6.8.
    // items: true,                    // 6.9.
    // additionalItems: true,          // 6.10.
    maxItems: true,                 // 6.11.
    minItems: true,                 // 6.12.
    uniqueItems: true,              // 6.13.
    // contains: true,                 // 6.14.
    maxProperties: true,            // 6.15.
    minProperties: true,            // 6.16.
    // required: true,                 // 6.17.  This is not required. It is auto-generated.
    // properties: true,               // 6.18.  This is not required. It is auto-generated.
    // patternProperties: true,        // 6.19.
    additionalProperties: true,     // 6.20.
    // dependencies: true,             // 6.21.
    // propertyNames: true,            // 6.22.
    enum: true,                     // 6.23.
    // const: true,                    // 6.24.
    type: true,                     // 6.25.
    // allOf: true,                    // 6.26.
    // anyOf: true,                    // 6.27.
    // oneOf: true,                    // 6.28.
    // not: true,                      // 6.29.

    ignore: true,
    description: true,
    format: true,
    default: true,
    $ref: true,
    id: true
};

export class JsonSchemaGenerator {
    private tc: ts.TypeChecker;

    /**
     * Holds all symbols within a custom SymbolRef object, containing useful
     * information.
     */
    private symbols: SymbolRef[];
    /**
     * All types for declarations of classes, interfaces, enums, and type aliases
     * defined in all TS files.
     */
    private allSymbols: { [name: string]: ts.Type };
    /**
     * All symbols for declarations of classes, interfaces, enums, and type aliases
     * defined in non-default-lib TS files.
     */
    private userSymbols: { [name: string]: ts.Symbol };
    /**
     * Maps from the names of base types to the names of the types that inherit from
     * them.
     */
    private inheritingTypes: { [baseName: string]: string[] };

    private reffedDefinitions: { [key: string]: Definition } = {};

    /**
     * This is a set of all the user-defined validation keywords.
     */
    private userValidationKeywords: ValidationKeywords;

    /**
     * Types are assigned names which are looked up by their IDs.  This is the
     * map from type IDs to type names.
     */
    private typeNamesById: { [id: number]: string } = {};
    /**
     * Whenever a type is assigned its name, its entry in this dictionary is set,
     * so that we don't give the same name to two separate types.
     */
    private typeNamesUsed: { [name: string]: boolean } = {};

    constructor(
      symbols: SymbolRef[],
      allSymbols: { [name: string]: ts.Type },
      userSymbols: { [name: string]: ts.Symbol },
      inheritingTypes: { [baseName: string]: string[] },
      tc: ts.TypeChecker,
      private args = getDefaultArgs(),
    ) {
        this.symbols = symbols;
        this.allSymbols = allSymbols;
        this.userSymbols = userSymbols;
        this.inheritingTypes = inheritingTypes;
        this.tc = tc;
        this.userValidationKeywords = args.validationKeywords.reduce(
          (acc, word) => ({ ...acc, [word]: true }),
          {}
        );
    }

    public get ReffedDefinitions(): { [key: string]: Definition } {
        return this.reffedDefinitions;
    }

    /**
     * Parse the comments of a symbol into the definition and other annotations.
     */
    private parseCommentsIntoDefinition(symbol: ts.Symbol, definition: {description?: string}, otherAnnotations: {}): void {
        if (!symbol) {
            return;
        }

        // the comments for a symbol
        const comments = symbol.getDocumentationComment(this.tc);

        if (comments.length) {
            definition.description = comments.map(comment => comment.kind === "lineBreak" ? comment.text : comment.text.trim().replace(/\r\n/g, "\n")).join("");
        }

        // jsdocs are separate from comments
        const jsdocs = symbol.getJsDocTags();
        jsdocs.forEach(doc => {
            // if we have @TJS-... annotations, we have to parse them
            const [name, text] = (doc.name === "TJS" ? new RegExp(REGEX_TJS_JSDOC).exec(doc.text!)!.slice(1,3) : [doc.name, doc.text]) as string[];
            if (validationKeywords[name] || this.userValidationKeywords[name]) {
                definition[name] = text === undefined ? "" : parseValue(text);
            } else {
                // special annotations
                otherAnnotations[doc.name] = true;
            }
        });
    }

    private getDefinitionForRootType(propertyType: ts.Type, reffedType: ts.Symbol, definition: Definition) {
        const tupleType = resolveTupleType(propertyType);

        if (tupleType) { // tuple
            const elemTypes: ts.NodeArray<ts.TypeNode> = tupleType.elementTypes || (propertyType as any).typeArguments;
            const fixedTypes = elemTypes.map(elType => this.getTypeDefinition(elType as any));
            definition.type = "array";
            definition.items = fixedTypes;
            definition.minItems = fixedTypes.length;
            definition.additionalItems = {
                anyOf: fixedTypes
            };
        } else {
            const propertyTypeString = this.tc.typeToString(propertyType, undefined, ts.TypeFormatFlags.UseFullyQualifiedType);
            const flags = propertyType.flags;
            const arrayType = this.tc.getIndexTypeOfType(propertyType, ts.IndexKind.Number);

            if (flags & ts.TypeFlags.String) {
                definition.type = "string";
            } else if (flags & ts.TypeFlags.Number) {
                const isInteger = (definition.type === "integer" || (reffedType && reffedType.getName() === "integer"));
                definition.type = isInteger ? "integer" : "number";
            } else if (flags & ts.TypeFlags.Boolean) {
                definition.type = "boolean";
            } else if (flags & ts.TypeFlags.Null) {
                definition.type = "null";
            } else if (flags & ts.TypeFlags.Undefined) {
                definition.type = "undefined";
            } else if (flags & ts.TypeFlags.Any) {
                // no type restriction, so that anything will match
            } else if (propertyTypeString === "Date") {
                definition.type = "string";
                definition.format = "date-time";
            }  else if (propertyTypeString === "object") {
                definition.type = "object";
                definition.properties = {};
                definition.additionalProperties = true;
            } else {
                const value = extractLiteralValue(propertyType);
                if (value !== undefined) {
                    definition.type = typeof value;
                    definition.enum = [ value ];
                } else if (arrayType !== undefined) {
                    definition.type = "array";
                    definition.items = this.getTypeDefinition(arrayType);
                } else {
                    // Report that type could not be processed
                    let info: any = propertyType;
                    try {
                        info = JSON.stringify(propertyType);
                    } catch(err) {}
                    console.error("Unsupported type: ", info);
                    // definition = this.getTypeDefinition(propertyType, tc);
                }
            }
        }

        return definition;
    }

    private getReferencedTypeSymbol(prop: ts.Symbol): ts.Symbol|undefined {
        const decl = prop.getDeclarations();
        if (decl && decl.length) {
            const type = (<ts.TypeReferenceNode> (<any> decl[0]).type);
            if (type && (type.kind & ts.SyntaxKind.TypeReference) && type.typeName) {
                return this.tc.getSymbolAtLocation(type.typeName);
            }
        }
        return undefined;
    }

    private getDefinitionForProperty(prop: ts.Symbol, node: ts.Node) {
        if (prop.flags & ts.SymbolFlags.Method) {
            return null;
        }
        const propertyName = prop.getName();
        const propertyType = this.tc.getTypeOfSymbolAtLocation(prop, node);

        const reffedType = this.getReferencedTypeSymbol(prop);

        const definition = this.getTypeDefinition(propertyType, undefined, undefined, prop, reffedType);

        if (this.args.titles) {
            definition.title = propertyName;
        }

        if (definition.hasOwnProperty("ignore")) {
            return null;
        }

        // try to get default value
        const valDecl = prop.valueDeclaration as ts.VariableDeclaration;
        if (valDecl && valDecl.initializer) {
            let initial = valDecl.initializer;

            while (ts.isTypeAssertion(initial)) {
                initial = initial.expression;
            }

            if ((<any>initial).expression) { // node
                console.warn("initializer is expression for property " + propertyName);
            } else if ((<any>initial).kind && (<any>initial).kind === ts.SyntaxKind.NoSubstitutionTemplateLiteral) {
                definition.default = initial.getText();
            } else {
                try {
                    const sandbox = { sandboxvar: null as any };
                    vm.runInNewContext("sandboxvar=" + initial.getText(), sandbox);

                    const val = sandbox.sandboxvar;
                    if (val === null || typeof val === "string" || typeof val === "number" || typeof val === "boolean" || Object.prototype.toString.call(val) === "[object Array]") {
                        definition.default = val;
                    } else if (val) {
                        console.warn("unknown initializer for property " + propertyName + ": " + val);
                    }
                } catch (e) {
                    console.warn("exception evaluating initializer for property " + propertyName);
                }
            }
        }

        return definition;
    }

    private getEnumDefinition(clazzType: ts.Type, definition: Definition): Definition {
        const node = clazzType.getSymbol()!.getDeclarations()![0];
        const fullName = this.tc.typeToString(clazzType, undefined, ts.TypeFormatFlags.UseFullyQualifiedType);
        const members: ts.NodeArray<ts.EnumMember> = node.kind === ts.SyntaxKind.EnumDeclaration ?
            (node as ts.EnumDeclaration).members :
            ts.createNodeArray([node as ts.EnumMember]);
        var enumValues: (number|boolean|string|null)[] = [];
        const enumTypes: string[] = [];

        const addType = (type: string) => {
            if (enumTypes.indexOf(type) === -1) {
                enumTypes.push(type);
            }
        };

        members.forEach(member => {
            const caseLabel = (<ts.Identifier>member.name).text;
            const constantValue = this.tc.getConstantValue(member);
            if (constantValue !== undefined) {
                enumValues.push(constantValue);
                addType(typeof constantValue);
            } else {
                // try to extract the enums value; it will probably by a cast expression
                const initial: ts.Expression|undefined = member.initializer;
                if (initial) {
                    if ((<any>initial).expression) { // node
                        const exp = (<any>initial).expression;
                        const text = (<any>exp).text;
                        // if it is an expression with a text literal, chances are it is the enum convension:
                        // CASELABEL = 'literal' as any
                        if (text) {
                            enumValues.push(text);
                            addType("string");
                        } else if (exp.kind === ts.SyntaxKind.TrueKeyword || exp.kind === ts.SyntaxKind.FalseKeyword) {
                            enumValues.push((exp.kind === ts.SyntaxKind.TrueKeyword));
                            addType("boolean");
                        } else {
                            console.warn("initializer is expression for enum: " + fullName + "." + caseLabel);
                        }
                    } else if (initial.kind === ts.SyntaxKind.NoSubstitutionTemplateLiteral) {
                        enumValues.push(initial.getText());
                        addType("string");
                    } else if (initial.kind === ts.SyntaxKind.NullKeyword) {
                        enumValues.push(null);
                        addType("null");
                    }
                }
            }
        });

        if (enumTypes.length) {
            definition.type = (enumTypes.length === 1) ? enumTypes[0] : enumTypes;
        }

        if (enumValues.length > 0) {
            definition.enum = enumValues.sort();
        }

        return definition;
    }

    private getUnionDefinition(unionType: ts.UnionType, prop: ts.Symbol, unionModifier: string, definition: Definition) {
        const enumValues: PrimitiveType[] = [];
        const simpleTypes: string[] = [];
        const schemas: Definition[] = [];

        const pushSimpleType = (type: string) => {
            if (simpleTypes.indexOf(type) === -1) {
                simpleTypes.push(type);
            }
        };

        const pushEnumValue = (val: PrimitiveType) => {
            if (enumValues.indexOf(val) === -1) {
                enumValues.push(val);
            }
        };

        for (const valueType of unionType.types) {
            const value = extractLiteralValue(valueType);
            if (value !== undefined) {
                pushEnumValue(value);
            } else {
                const def = this.getTypeDefinition(valueType);
                if (def.type === "undefined") {
                    if (prop) {
                        (<any>prop).mayBeUndefined = true;
                    }
                } else {
                    const keys = Object.keys(def);
                    if (keys.length === 1 && keys[0] === "type") {
                        if (typeof def.type !== "string") {
                            console.error("Expected only a simple type.");
                        } else {
                            pushSimpleType(def.type);
                        }
                    } else {
                        schemas.push(def);
                    }
                }
            }
        }

        if (enumValues.length > 0) {
            // If the values are true and false, just add "boolean" as simple type
            const isOnlyBooleans = enumValues.length === 2 &&
                typeof enumValues[0] === "boolean" &&
                typeof enumValues[1] === "boolean" &&
                enumValues[0] !== enumValues[1];

            if (isOnlyBooleans) {
                pushSimpleType("boolean");
            } else {
                const enumSchema: Definition = { enum: enumValues.sort() };

                // If all values are of the same primitive type, add a "type" field to the schema
                if (enumValues.every((x) => { return typeof x === "string"; })) {
                    enumSchema.type = "string";
                } else if (enumValues.every((x) => { return typeof x === "number"; })) {
                    enumSchema.type = "number";
                } else if (enumValues.every((x) => { return typeof x === "boolean"; })) {
                    enumSchema.type = "boolean";
                }

                schemas.push(enumSchema);
            }
        }

        if (simpleTypes.length > 0) {
            schemas.push({ type: simpleTypes.length === 1 ? simpleTypes[0] : simpleTypes });
        }

        if (schemas.length === 1) {
            for (const k in schemas[0]) {
                if (schemas[0].hasOwnProperty(k)) {
                    definition[k] = schemas[0][k];
                }
            }
        } else {
            definition[unionModifier] = schemas;
        }
        return definition;
    }

    private getIntersectionDefinition(intersectionType: ts.IntersectionType, definition: Definition) {
        const simpleTypes: string[] = [];
        const schemas: Definition[] = [];

        const pushSimpleType = (type: string) => {
            if (simpleTypes.indexOf(type) === -1) {
                simpleTypes.push(type);
            }
        };

        for (const intersectionMember of intersectionType.types) {
            const def = this.getTypeDefinition(intersectionMember);
            if (def.type === "undefined") {
                console.error("Undefined in intersection makes no sense.");
            } else {
                const keys = Object.keys(def);
                if (keys.length === 1 && keys[0] === "type") {
                    if (typeof def.type !== "string") {
                        console.error("Expected only a simple type.");
                    } else {
                        pushSimpleType(def.type);
                    }
                } else {
                    schemas.push(def);
                }
            }
        }

        if (simpleTypes.length > 0) {
            schemas.push({ type: simpleTypes.length === 1 ? simpleTypes[0] : simpleTypes });
        }

        if (schemas.length === 1) {
            for (const k in schemas[0]) {
                if (schemas[0].hasOwnProperty(k)) {
                    definition[k] = schemas[0][k];
                }
            }
        } else {
            definition.allOf = schemas;
        }
        return definition;
    }


    private getClassDefinition(clazzType: ts.Type, definition: Definition): Definition {
        const node = clazzType.getSymbol()!.getDeclarations()![0];
        if (this.args.typeOfKeyword && node.kind === ts.SyntaxKind.FunctionType) {
            definition.typeof = "function";
            return definition;
        }

        const clazz = <ts.ClassDeclaration>node;
        const props = this.tc.getPropertiesOfType(clazzType).filter(prop => {
            if (!this.args.excludePrivate) {
                return true;
            }

            const decls = prop.declarations;
            return !(decls && decls.filter(decl => {
                const mods = decl.modifiers;
                return mods && mods.filter(mod => mod.kind === ts.SyntaxKind.PrivateKeyword).length > 0;
            }).length > 0);
        });
        const fullName = this.tc.typeToString(clazzType, undefined, ts.TypeFormatFlags.UseFullyQualifiedType);

        const modifierFlags = ts.getCombinedModifierFlags(node);

        if (modifierFlags & ts.ModifierFlags.Abstract) {
            const oneOf = this.inheritingTypes[fullName].map((typename) => {
                return this.getTypeDefinition(this.allSymbols[typename]);
            });

            definition.oneOf = oneOf;
        } else {
            if (clazz.members) {
                const indexSignatures = clazz.members == null ? [] : clazz.members.filter(x => x.kind === ts.SyntaxKind.IndexSignature);
                if (indexSignatures.length === 1) {
                    // for case "array-types"
                    const indexSignature = indexSignatures[0] as ts.IndexSignatureDeclaration;
                    if (indexSignature.parameters.length !== 1) {
                        throw new Error("Not supported: IndexSignatureDeclaration parameters.length != 1");
                    }
                    const indexSymbol: ts.Symbol = (<any>indexSignature.parameters[0]).symbol;
                    const indexType = this.tc.getTypeOfSymbolAtLocation(indexSymbol, node);
                    const isStringIndexed = (indexType.flags === ts.TypeFlags.String);
                    if (indexType.flags !== ts.TypeFlags.Number && !isStringIndexed) {
                        throw new Error("Not supported: IndexSignatureDeclaration with index symbol other than a number or a string");
                    }

                    const typ = this.tc.getTypeAtLocation(indexSignature.type!);
                    const def = this.getTypeDefinition(typ, undefined, "anyOf");

                    if (isStringIndexed) {
                        definition.type = "object";
                        definition.additionalProperties = def;
                    } else {
                        definition.type = "array";
                        definition.items = def;
                    }
                }
            }

            const propertyDefinitions = props.reduce((all, prop) => {
                const propertyName = prop.getName();
                const propDef = this.getDefinitionForProperty(prop, node);
                if (propDef != null) {
                    all[propertyName] = propDef;
                }
                return all;
            }, {});

            if (definition.type === undefined) {
                definition.type = "object";
            }

            if (definition.type === "object" && Object.keys(propertyDefinitions).length > 0) {
                definition.properties = propertyDefinitions;
            }

            if (this.args.defaultProps) {
                definition.defaultProperties = [];
            }
            if (this.args.noExtraProps && definition.additionalProperties === undefined) {
                definition.additionalProperties = false;
            }
            if (this.args.propOrder) {
                // propertyOrder is non-standard, but useful:
                // https://github.com/json-schema/json-schema/issues/87
                const propertyOrder = props.reduce((order: string[], prop: ts.Symbol) => {
                    order.push(prop.getName());
                    return order;
                }, []);

                definition.propertyOrder = propertyOrder;
            }
            if (this.args.required) {
                const requiredProps = props.reduce((required: string[], prop: ts.Symbol) => {
                    const def = {};
                    this.parseCommentsIntoDefinition(prop, def, {});
                    if (!(prop.flags & ts.SymbolFlags.Optional) && !(prop.flags & ts.SymbolFlags.Method) && !(<any>prop).mayBeUndefined && !def.hasOwnProperty("ignore")) {
                        required.push(prop.getName());
                    }
                    return required;
                }, []);

                if (requiredProps.length > 0) {
                    definition.required = unique(requiredProps).sort();
                }
            }
        }
        return definition;
    }

    /**
     * Gets/generates a globally unique type name for the given type
     */
    private getTypeName(typ: ts.Type) {
        const id = (typ as any).id as number;
        if (this.typeNamesById[id]) { // Name already assigned?
            return this.typeNamesById[id];
        }

        const baseName = this.tc.typeToString(typ, undefined, ts.TypeFormatFlags.UseFullyQualifiedType);
        let name = baseName;
        if (this.typeNamesUsed[name]) { // If a type with same name exists
            for (let i = 1; true; ++i) { // Try appending "_1", "_2", etc.
                name = baseName + "_" + i;
                if (!this.typeNamesUsed[name]) {
                    break;
                }
            }
        }

        this.typeNamesById[id] = name;
        this.typeNamesUsed[name] = true;
        return name;
    }

    private getTypeDefinition(typ: ts.Type, asRef = this.args.ref, unionModifier: string = "anyOf", prop?: ts.Symbol, reffedType?: ts.Symbol, pairedSymbol?: ts.Symbol): Definition {
        const definition: Definition = {}; // real definition

        if (this.args.typeOfKeyword && (typ.flags & ts.TypeFlags.Object) && ((<ts.ObjectType>typ).objectFlags & ts.ObjectFlags.Anonymous)) {
            definition.typeof = "function";
            return definition;
        }

        let returnedDefinition = definition; // returned definition, may be a $ref

        const symbol = typ.getSymbol();
        // FIXME: We can't just compare the name of the symbol - it ignores the namespace
        const isRawType = (!symbol || symbol.name === "Date" || symbol.name === "integer" || this.tc.getIndexInfoOfType(typ, ts.IndexKind.Number) !== undefined);

        // special case: an union where all child are string literals -> make an enum instead
        let isStringEnum = false;
        if (typ.flags & ts.TypeFlags.Union) {
            const unionType = <ts.UnionType>typ;
            isStringEnum = (unionType.types.every(propType => {
                return (propType.getFlags() & ts.TypeFlags.StringLiteral) !== 0;
            }));
        }

        // aliased types must be handled slightly different
        const asTypeAliasRef = asRef && reffedType && (this.args.aliasRef || isStringEnum);
        if (!asTypeAliasRef) {
            if (isRawType || typ.getFlags() & ts.TypeFlags.Object && (<ts.ObjectType>typ).objectFlags & ts.ObjectFlags.Anonymous) {
                asRef = false;  // raw types and inline types cannot be reffed,
                                // unless we are handling a type alias
            }
        }

        let fullTypeName = "";
        if (asTypeAliasRef) {
            fullTypeName = this.tc.getFullyQualifiedName(
                reffedType!.getFlags() & ts.SymbolFlags.Alias ?
                    this.tc.getAliasedSymbol(reffedType!) :
                    reffedType!
            ).replace(REGEX_FILE_NAME, "");
        } else if (asRef) {
            fullTypeName = this.getTypeName(typ);
        }

        fullTypeName = fullTypeName.replace(" ", "");

        if (asRef) {
            // We don't return the full definition, but we put it into
            // reffedDefinitions below.
            returnedDefinition = {
                $ref:  "#/definitions/" + fullTypeName
            };
        }

        // Parse comments
        const otherAnnotations = {};
        this.parseCommentsIntoDefinition(reffedType!, definition, otherAnnotations); // handle comments in the type alias declaration
        if (prop) {
            this.parseCommentsIntoDefinition(prop, returnedDefinition, otherAnnotations);
        }
        this.parseCommentsIntoDefinition(symbol!, definition, otherAnnotations);

        // Create the actual definition only if is an inline definition, or
        // if it will be a $ref and it is not yet created
        if (!asRef || !this.reffedDefinitions[fullTypeName]) {
            if (asRef) { // must be here to prevent recursivity problems
                let reffedDefinition: Definition;
                if (asTypeAliasRef && reffedType!.getFlags() & (ts.TypeFlags.IndexedAccess | ts.TypeFlags.Index) && symbol) {
                    reffedDefinition = this.getTypeDefinition(typ, true, undefined, symbol, symbol);
                } else {
                    reffedDefinition = definition;
                }
                this.reffedDefinitions[fullTypeName] =  reffedDefinition;
                if (this.args.titles && fullTypeName) {
                    definition.title = fullTypeName;
                }
            }
            const node = symbol && symbol.getDeclarations() !== undefined ? symbol.getDeclarations()![0] : null;

            if (definition.type === undefined) {  // if users override the type, do not try to infer it
                if (typ.flags & ts.TypeFlags.Union) {
                    this.getUnionDefinition(typ as ts.UnionType, prop!, unionModifier, definition);
                } else if (typ.flags & ts.TypeFlags.Intersection) {
                    if (this.args.noExtraProps) {
                        // extend object instead of using allOf because allOf does not work well with additional properties. See #107
                        if (this.args.noExtraProps) {
                            definition.additionalProperties = false;
                        }

                        const types = (<ts.IntersectionType> typ).types;
                        for (const member of types) {
                            const other = this.getTypeDefinition(member, false);
                            definition.type = other.type;  // should always be object
                            definition.properties = extend(definition.properties || {}, other.properties);
                            if (Object.keys(other.default || {}).length > 0) {
                                definition.default = extend(definition.default || {}, other.default);
                            }
                            if (other.required) {
                                definition.required = unique((definition.required || []).concat(other.required)).sort();
                            }
                        }
                    } else {
                        this.getIntersectionDefinition(typ as ts.IntersectionType, definition);
                    }
                } else if (isRawType) {
                    if (pairedSymbol) {
                        this.parseCommentsIntoDefinition(pairedSymbol, definition, {});
                    }
                    this.getDefinitionForRootType(typ, reffedType!, definition);
                } else if (node && (node.kind === ts.SyntaxKind.EnumDeclaration || node.kind === ts.SyntaxKind.EnumMember)) {
                    this.getEnumDefinition(typ, definition);
                } else if (symbol && symbol.flags & ts.SymbolFlags.TypeLiteral && symbol.members!.size === 0 && !(node && (node.kind === ts.SyntaxKind.MappedType))) {
                    // {} is TypeLiteral with no members. Need special case because it doesn't have declarations.
                    definition.type = "object";
                    definition.properties = {};
                } else {
                    this.getClassDefinition(typ, definition);
                }
            }
        }

        if (otherAnnotations["nullable"]) {
            makeNullable(returnedDefinition);
        }

        return returnedDefinition;
    }

    public setSchemaOverride(symbolName: string, schema: Definition) {
        this.reffedDefinitions[symbolName] = schema;
    }

    public getSchemaForSymbol(symbolName: string, includeReffedDefinitions: boolean = true): Definition {
        if(!this.allSymbols[symbolName]) {
            throw new Error(`type ${symbolName} not found`);
        }
        const def = this.getTypeDefinition(this.allSymbols[symbolName], this.args.topRef, undefined, undefined, undefined, this.userSymbols[symbolName] || undefined);

        if (this.args.ref && includeReffedDefinitions && Object.keys(this.reffedDefinitions).length > 0) {
            def.definitions = this.reffedDefinitions;
        }
        def["$schema"] = "http://json-schema.org/draft-07/schema#";
        return def;
    }

    public getSchemaForSymbols(symbolNames: string[], includeReffedDefinitions: boolean = true): Definition {
        const root = {
            $schema: "http://json-schema.org/draft-07/schema#",
            definitions: {}
        };
        for (const symbolName of symbolNames) {
            root.definitions[symbolName] = this.getTypeDefinition(this.allSymbols[symbolName], this.args.topRef, undefined, undefined, undefined, this.userSymbols[symbolName]);
        }
        if (this.args.ref && includeReffedDefinitions && Object.keys(this.reffedDefinitions).length > 0) {
            root.definitions = {...root.definitions, ... this.reffedDefinitions};
        }
        return root;
    }

    public getSymbols(name?: string): SymbolRef[] {
      if (name === void 0) {
        return this.symbols;
      }

      return this.symbols.filter(symbol => symbol.typeName === name);
    }

    public getUserSymbols(): string[] {
        return Object.keys(this.userSymbols);
    }

    public getMainFileSymbols(program: ts.Program, onlyIncludeFiles?: string[]): string[] {
        function includeFile(file: ts.SourceFile): boolean {
            if (onlyIncludeFiles === undefined) {
                return !file.isDeclarationFile;
            }
            return onlyIncludeFiles.indexOf(file.fileName) >= 0;
        }
        const files = program.getSourceFiles().filter(includeFile);
        if (files.length) {
            return Object.keys(this.userSymbols).filter((key) => {
                const symbol = this.userSymbols[key];
                if (!symbol || !symbol.declarations || !symbol.declarations.length) {
                    return false;
                }
                let node: ts.Node = symbol.declarations[0];
                while (node && node.parent) {
                    node = node.parent;
                }
                return files.indexOf(node.getSourceFile()) > -1;
            });
        }
        return [];
    }
}

export function getProgramFromFiles(files: string[], jsonCompilerOptions: any = {}, basePath: string = "./"): ts.Program {
    // use built-in default options
    const compilerOptions = ts.convertCompilerOptionsFromJson(jsonCompilerOptions, basePath).options;
    const options: ts.CompilerOptions = {
        noEmit: true, emitDecoratorMetadata: true, experimentalDecorators: true, target: ts.ScriptTarget.ES5, module: ts.ModuleKind.CommonJS, allowUnusedLabels: true,
    };
    for (const k in compilerOptions) {
        if (compilerOptions.hasOwnProperty(k)) {
            options[k] = compilerOptions[k];
        }
    }
    return ts.createProgram(files, options);
}

export function buildGenerator(program: ts.Program, args: PartialArgs = {}, onlyIncludeFiles?: string[]): JsonSchemaGenerator|null {
    function isUserFile(file: ts.SourceFile): boolean {
        if (onlyIncludeFiles === undefined) {
            return !file.hasNoDefaultLib;
        }
        return onlyIncludeFiles.indexOf(file.fileName) >= 0;
    }
    // Use defaults unles otherwise specified
    const settings = getDefaultArgs();

    for (const pref in args) {
        if (args.hasOwnProperty(pref)) {
            settings[pref] = args[pref];
        }
    }

    let diagnostics: Array<ts.Diagnostic> = [];

    if (!args.ignoreErrors) {
        diagnostics = ts.getPreEmitDiagnostics(program);
    }

    if (diagnostics.length === 0) {
        const typeChecker = program.getTypeChecker();

        const symbols: SymbolRef[] = [];
        const allSymbols: { [name: string]: ts.Type } = {};
        const userSymbols: { [name: string]: ts.Symbol } = {};
        const inheritingTypes: { [baseName: string]: string[] } = {};

        program.getSourceFiles().forEach((sourceFile, _sourceFileIdx) => {
            function inspect(node: ts.Node, tc: ts.TypeChecker) {

                if (node.kind === ts.SyntaxKind.ClassDeclaration
                  || node.kind === ts.SyntaxKind.InterfaceDeclaration
                  || node.kind === ts.SyntaxKind.EnumDeclaration
                  || node.kind === ts.SyntaxKind.TypeAliasDeclaration
                ) {
                    const symbol: ts.Symbol = (<any>node).symbol;
                    const nodeType = tc.getTypeAtLocation(node);
                    const fullyQualifiedName = tc.getFullyQualifiedName(symbol);
                    const typeName = fullyQualifiedName.replace(/".*"\./, "");
                    const name = !args.uniqueNames ? typeName : `${typeName}.${(<any>symbol).id}`;

                    symbols.push({ name, typeName, fullyQualifiedName, symbol });
                    if (!userSymbols[name]) {
                        allSymbols[name] = nodeType;
                    }

                    if (isUserFile(sourceFile)) {
                        userSymbols[name] = symbol;
                    }

                    const baseTypes = nodeType.getBaseTypes() || [];

                    baseTypes.forEach(baseType => {
                        var baseName = tc.typeToString(baseType, undefined, ts.TypeFormatFlags.UseFullyQualifiedType);
                        if (!inheritingTypes[baseName]) {
                            inheritingTypes[baseName] = [];
                        }
                        inheritingTypes[baseName].push(name);
                    });
                } else {
                    ts.forEachChild(node, n => inspect(n, tc));
                }
            }
            inspect(sourceFile, typeChecker);
        });

        return new JsonSchemaGenerator(symbols, allSymbols, userSymbols, inheritingTypes, typeChecker, settings);
    } else {
        diagnostics.forEach((diagnostic) => {
            const message = ts.flattenDiagnosticMessageText(diagnostic.messageText, "\n");
            if(diagnostic.file) {
                const { line, character } = diagnostic.file.getLineAndCharacterOfPosition(diagnostic.start!);
                console.error(`${diagnostic.file.fileName} (${line + 1},${character + 1}): ${message}`);
            } else {
                console.error(message);
            }
        });
        return null;
    }
}

export function generateSchema(program: ts.Program, fullTypeName: string, args: PartialArgs = {}, onlyIncludeFiles?: string[]): Definition|null {
    const generator = buildGenerator(program, args, onlyIncludeFiles);

    if (generator === null) {
        return null;
    }

    if (fullTypeName === "*") { // All types in file(s)
        return generator.getSchemaForSymbols(generator.getMainFileSymbols(program, onlyIncludeFiles));
    } else { // Use specific type as root object
        return generator.getSchemaForSymbol(fullTypeName);
    }
}

export function programFromConfig(configFileName: string, onlyIncludeFiles?: string[]): ts.Program {
    // basically a copy of https://github.com/Microsoft/TypeScript/blob/3663d400270ccae8b69cbeeded8ffdc8fa12d7ad/src/compiler/tsc.ts -> parseConfigFile
    const result = ts.parseConfigFileTextToJson(configFileName, ts.sys.readFile(configFileName)!);
    const configObject = result.config;

    const configParseResult = ts.parseJsonConfigFileContent(configObject, ts.sys, path.dirname(configFileName), {}, path.basename(configFileName));
    const options = configParseResult.options;
    options.noEmit = true;
    delete options.out;
    delete options.outDir;
    delete options.outFile;
    delete options.declaration;

    const program = ts.createProgram(onlyIncludeFiles || configParseResult.fileNames, options);
    return program;
}

function normalizeFileName(fn: string): string {
    while (fn.substr(0, 2) === "./") {
        fn = fn.substr(2);
    }
    return fn;
}

export function exec(filePattern: string, fullTypeName: string, args = getDefaultArgs()) {
    let program: ts.Program;
    let onlyIncludeFiles: string[] | undefined = undefined;
    if (REGEX_TSCONFIG_NAME.test(path.basename(filePattern))) {
        if (args.include && args.include.length > 0) {
            const globs: string[][] = args.include.map(f => glob.sync(f));
            onlyIncludeFiles = ([] as string[]).concat(...globs).map(normalizeFileName);
        }
        program = programFromConfig(filePattern, onlyIncludeFiles);
    } else {
        onlyIncludeFiles = glob.sync(filePattern);
        program = getProgramFromFiles(onlyIncludeFiles, {
            strictNullChecks: args.strictNullChecks
        });
        onlyIncludeFiles = onlyIncludeFiles.map(normalizeFileName);
    }

    const definition = generateSchema(program, fullTypeName, args, onlyIncludeFiles);
    if (definition === null) {
        return;
    }

    const json = stringify(definition, {space: 4}) + "\n\n";
    if (args.out) {
        require("fs").writeFile(args.out, json, function(err: Error) {
            if (err) {
                console.error("Unable to write output file: " + err.message);
            }
        });
    } else {
        process.stdout.write(json);
    }
}