import {
  ChangeDetectionStrategy, Component, DoCheck, EventEmitter, Input, Output,
  OnChanges, OnInit,
} from '@angular/core';
import { FormGroup } from '@angular/forms';

import * as _ from 'lodash';

import { FrameworkLibraryService } from '../frameworks/framework-library.service';
import { WidgetLibraryService } from '../widgets/widget-library.service';
import { JsonSchemaFormService } from './json-schema-form.service';
import {
  hasOwn, hasValue, isArray, isEmpty, isObject, JsonPointer
} from './utilities/index';

/**
 * @module 'JsonSchemaFormComponent' - Angular 2 JSON Schema Form
 *
 * Root module of the Angular 2 JSON Schema Form client-side library,
 * an Angular 2 library which generates an HTML form from a JSON schema
 * structured data model and/or a JSON Schema Form layout description.
 *
 * This library also validates input data by the user, both using individual
 * validators which provide real-time feedback while the user is filling out
 * the form, and then using the entire schema when the form is submitted,
 * to make sure the returned JSON data object is valid.
 *
 * This library is similar to, and mostly API compatible with:
 *
 * - JSON Schema Form's Angular Schema Form library for AngularJs
 *   http://schemaform.io
 *   http://schemaform.io/examples/bootstrap-example.html (examples)
 *
 * - Joshfire's JSON Form library for jQuery
 *   https://github.com/joshfire/jsonform
 *   http://ulion.github.io/jsonform/playground (examples)
 *
 * - Mozilla's react-jsonschema-form library for React
 *   https://github.com/mozilla-services/react-jsonschema-form
 *   https://mozilla-services.github.io/react-jsonschema-form (examples)
 *
 * This library depends on:
 *  - Angular 2 (obviously)                https://angular.io
 *  - lodash, JavaScript utility library   https://github.com/lodash/lodash
 *  - ajv, Another JSON Schema validator   https://github.com/epoberezkin/ajv
 * In addition, the testing playground also depends on:
 *  - brace, Browserified Ace editor       http://thlorenz.github.io/brace
 */
@Component({
  selector: 'json-schema-form',
  template: `
    <form (ngSubmit)="submitForm()">
      <root-widget [formID]="formID" [layout]="jsf.layout"></root-widget>
    </form>
    <div *ngIf="debug || jsf.globalOptions.debug">
      Debug output: <pre>{{debugOutput}}</pre>
    </div>`,
  providers: [ JsonSchemaFormService ],
  changeDetection: ChangeDetectionStrategy.OnPush,
})
export class JsonSchemaFormComponent implements DoCheck, OnChanges, OnInit {
  private formID: number; // Unique ID for displayed form
  private debugOutput: any; // Debug information, if requested
  private formValueSubscription: any = null;

  // Recommended inputs
  @Input() schema: any; // The JSON Schema
  @Input() layout: any[]; // The form layout
  @Input() data: any; // The data model
  @Input() options: any; // The global form options
  @Input() framework: string; // The framework to load
  @Input() widgets: string; // Any custom widgets to load

  // Alternate combined single input
  @Input() form: any; // For testing, and JSON Schema Form API compatibility

  // Angular Schema Form API compatibility inputs
  @Input() model: any; // Alternate input for data model

  // React JSON Schema Form API compatibility inputs
  @Input() JSONSchema: any; // Alternate input for JSON Schema
  @Input() UISchema: any; // UI schema - alternate form layout format
  @Input() formData: any; // Alternate input for data model

  // Development inputs, for testing and debugging
  @Input() loadExternalAssets: boolean; // Load external framework assets?
  @Input() debug: boolean; // Show debug information?

  // Outputs
  @Output() onChanges = new EventEmitter<any>(); // Live unvalidated internal form data
  @Output() onSubmit = new EventEmitter<any>(); // Complete validated form data
  @Output() isValid = new EventEmitter<boolean>(); // Is current data valid?
  @Output() validationErrors = new EventEmitter<any>(); // Validation errors (if any)
  @Output() formSchema = new EventEmitter<any>(); // Final schema used to create form
  @Output() formLayout = new EventEmitter<any>(); // Final layout used to create form

  constructor(
    private frameworkLibrary: FrameworkLibraryService,
    private widgetLibrary: WidgetLibraryService,
    private jsf: JsonSchemaFormService
  ) { }

  ngOnInit() {
    this.initializeForm();
  }

  ngOnChanges() {
    this.initializeForm();
  }

  /**
   * 'initializeForm' function
   *
   * - Update 'schema', 'layout', and 'initialValues', from inputs.
   *
   * - Create 'dataMap' to map the data to the schema and template.
   *
   * - Create 'schemaRefLibrary' to resolve schema $ref links.
   *
   * - Create 'layoutRefLibrary' to use when dynamically adding
   *   form components to arrays and recursive $ref points.
   *
   * - Create 'formGroupTemplate', then from it 'formGroup',
   *   the Angular 2 formGroup used to control the reactive form.
   *
   * @return {void}
   */
  public initializeForm(): void {
    if (
      this.schema || this.layout || this.data ||
      this.form || this.JSONSchema || this.UISchema
    ) {
      // Reset all form values to defaults
      this.jsf.resetAllValues();

      // Initialize 'options' (global form options) and set framework
      // Combine available inputs:
      // 1. options - recommended
      // 2. form.options - Single input style
      this.jsf.setOptions({ debug: !!this.debug });
      let loadExternalAssets: boolean = this.loadExternalAssets || false;
      let framework: any = this.framework || 'default';
      if (isObject(this.options)) {
        this.jsf.setOptions(this.options);
        loadExternalAssets = this.options.loadExternalAssets || loadExternalAssets;
        framework = this.options.framework || framework;
      }
      if (isObject(this.form) && isObject(this.form.options)) {
        this.jsf.setOptions(this.form.options);
        loadExternalAssets = this.form.options.loadExternalAssets || loadExternalAssets;
        framework = this.form.options.framework || framework;
      }
      if (isObject(this.widgets)) {
        this.jsf.setOptions({ widgets: this.widgets });
      }
      this.frameworkLibrary.setLoadExternalAssets(loadExternalAssets);
      this.frameworkLibrary.setFramework(framework);
      this.jsf.framework = this.frameworkLibrary.getFramework();
      if (isObject(this.jsf.globalOptions.widgets)) {
        for (let widget of Object.keys(this.jsf.globalOptions.widgets)) {
          this.widgetLibrary.registerWidget(widget, this.jsf.globalOptions.widgets[widget]);
        }
      }
      if (isObject(this.form) && isObject(this.form.tpldata)) {
        this.jsf.setTpldata(this.form.tpldata);
      }

      // Initialize 'schema'
      // Use first available input:
      // 1. schema - recommended / Angular Schema Form style
      // 2. form.schema - Single input / JSON Form style
      // 3. JSONSchema - React JSON Schema Form style
      // 4. form.JSONSchema - For testing single input React JSON Schema Forms
      // 5. form - For testing single schema-only inputs
      // TODO: 6. (none) no schema - construct form entirely from layout instead
      if (isObject(this.schema)) {
        this.jsf.AngularSchemaFormCompatibility = true;
        this.jsf.schema = _.cloneDeep(this.schema);
      } else if (hasOwn(this.form, 'schema') && isObject(this.form.schema)) {
        this.jsf.schema = _.cloneDeep(this.form.schema);
      } else if (isObject(this.JSONSchema)) {
        this.jsf.ReactJsonSchemaFormCompatibility = true;
        this.jsf.schema = _.cloneDeep(this.JSONSchema);
      } else if (hasOwn(this.form, 'JSONSchema') && isObject(this.form.JSONSchema)) {
        this.jsf.ReactJsonSchemaFormCompatibility = true;
        this.jsf.schema = _.cloneDeep(this.form.JSONSchema);
      } else if (hasOwn(this.form, 'properties') && isObject(this.form.properties)) {
        this.jsf.schema = _.cloneDeep(this.form);
      }

      if (!isEmpty(this.jsf.schema)) {

        // Allow for JSON schema shorthand (JSON Form style)
        if (!hasOwn(this.jsf.schema, 'type') &&
          hasOwn(this.jsf.schema, 'properties') &&
          isObject(this.jsf.schema.properties)
        ) {
          this.jsf.schema.type = 'object';
        } else if (!hasOwn(this.jsf.schema, 'type') ||
          this.jsf.schema.type !== 'object' ||
          !hasOwn(this.jsf.schema, 'properties')
        ) {
          this.jsf.JsonFormCompatibility = true;
          this.jsf.schema = {
            'type': 'object', 'properties': this.jsf.schema
          };
        }

        // If JSON Schema is version 3 (JSON Form style), convert it to version 4
        this.jsf.convertJsonSchema3to4();

        // Initialize ajv and compile schema
        this.jsf.compileAjvSchema();

        // Resolve all schema $ref links
        this.jsf.resolveSchemaRefLinks();
      }

      // Initialize 'layout'
      // Use first available array input:
      // 1. layout - recommended
      // 2. form - Angular Schema Form style
      // 3. form.form - JSON Form style
      // 4. form.layout - Single input style
      // 5. (none) no input - use default layout instead
      if (isArray(this.layout)) {
        this.jsf.layout = _.cloneDeep(this.layout);
      } else if (isArray(this.form)) {
        this.jsf.AngularSchemaFormCompatibility = true;
        this.jsf.layout = _.cloneDeep(this.form);
      } else if (this.form && isArray(this.form.form)) {
        this.jsf.JsonFormCompatibility = true;
        this.jsf.layout =
          this.jsf.fixJsonFormOptions(_.cloneDeep(this.form.form));
      } else if (this.form && isArray(this.form.layout)) {
        this.jsf.layout = _.cloneDeep(this.form.layout);
      } else {
        this.jsf.layout =
          this.jsf.globalOptions.addSubmit === false ?
          [ '*' ] :
          [ '*', { type: 'submit', title: 'Submit' } ];
      }

      // Import alternate layout formats 'UISchema' or 'customFormItems'
      // used for React JSON Schema Form and JSON Form API compatibility
      // Use first available input:
      // 1. UISchema - React JSON Schema Form style
      // 2. form.UISchema - For testing single input React JSON Schema Forms
      // 2. form.customFormItems - JSON Form style
      // 3. (none) no input - don't import
      let alternateLayout: any = null;
      if (isObject(this.UISchema)) {
        this.jsf.ReactJsonSchemaFormCompatibility = true;
        alternateLayout = _.cloneDeep(this.UISchema);
      } else if (hasOwn(this.form, 'UISchema')) {
        this.jsf.ReactJsonSchemaFormCompatibility = true;
        alternateLayout = _.cloneDeep(this.form.UISchema);
      } else if (hasOwn(this.form, 'customFormItems')) {
        this.jsf.JsonFormCompatibility = true;
        alternateLayout =
          this.jsf.fixJsonFormOptions(_.cloneDeep(this.form.customFormItems));
      }

      // if alternate layout found, copy options into schema
      if (alternateLayout) {
        JsonPointer.forEachDeep(alternateLayout, (value, pointer) => {
          const schemaPointer: string = pointer.replace(/\//g, '/properties/')
            .replace(/\/properties\/items\/properties\//g, '/items/properties/')
            .replace(/\/properties\/titleMap\/properties\//g, '/titleMap/properties/');
          if (hasValue(value) && hasValue(pointer)) {
            const groupPointer: string[] =
              JsonPointer.parse(schemaPointer).slice(0, -2);
            let key = JsonPointer.toKey(schemaPointer);
            let itemPointer: string | string[];
            // If 'ui:order' object found, copy into schema root
            if (key === 'ui:order') {
              itemPointer = schemaPointer;
            // Copy other alternate layout options to schema 'x-schema-form',
            // (like Angular Schema Form options) and remove any 'ui:' prefixes
            } else {
              itemPointer = groupPointer.concat(['x-schema-form',
                key.slice(0, 3) === 'ui:' ? key.slice(3) : key
              ]);
            }
            if (JsonPointer.has(this.jsf.schema, groupPointer) &&
              !JsonPointer.has(this.jsf.schema, itemPointer)
            ) {
              JsonPointer.set(this.jsf.schema, itemPointer, value);
            }
          }
        });
      }

      // Initialize 'initialValues'
      // Use first available input:
      // 1. data - recommended
      // 2. model - Angular Schema Form style
      // 3. form.value - JSON Form style
      // 4. form.data - Single input style
      // 5. formData - React JSON Schema Form style
      // 6. form.formData - For easier testing of React JSON Schema Forms
      // 7. (none) no data - initialize data from schema and layout defaults only
      if (isObject(this.data)) {
        this.jsf.initialValues = _.cloneDeep(this.data);
      } else if (isObject(this.model)) {
        this.jsf.AngularSchemaFormCompatibility = true;
        this.jsf.initialValues = _.cloneDeep(this.model);
      } else if (isObject(this.form) && isObject(this.form.value)) {
        this.jsf.JsonFormCompatibility = true;
        this.jsf.initialValues = _.cloneDeep(this.form.value);
      } else if (isObject(this.form) && isObject(this.form.data)) {
        this.jsf.initialValues = _.cloneDeep(this.form.data);
      } else if (isObject(this.formData)) {
        this.jsf.ReactJsonSchemaFormCompatibility = true;
        this.jsf.initialValues = _.cloneDeep(this.formData);
      } else if (hasOwn(this.form, 'formData') && isObject(this.form.formData)) {
        this.jsf.ReactJsonSchemaFormCompatibility = true;
        this.jsf.initialValues = _.cloneDeep(this.form.formData);
      }

      if (isEmpty(this.jsf.schema)) {

        // TODO: If layout, but no schema, build schema from layout
        if (this.jsf.layout.indexOf('*') === -1) {
          this.jsf.buildSchemaFromLayout();

        // If no schema and no layout, build schema from data
        } else if (!isEmpty(this.jsf.initialValues)) {
          this.jsf.buildSchemaFromData();
        }
      }

      if (!isEmpty(this.jsf.schema)) {

        // If not already initialized, initialize ajv and compile schema
        this.jsf.compileAjvSchema();

        // Build the Angular 2 FormGroup template from the schema
        this.jsf.buildFormGroupTemplate();

        // Update all layout elements, add values, widgets, and validators,
        // replace any '*' with a layout built from all schema elements,
        // and update the FormGroup template with any new validators
        this.jsf.buildLayout(this.widgetLibrary);

        // Build the real Angular 2 FormGroup from the FormGroup template
        this.jsf.buildFormGroup();
      }

      if (this.jsf.formGroup) {

        // // Calculate references to other fields
        // if (!isEmpty(this.jsf.formGroup.value)) {
        //   forEach(this.jsf.formGroup.value, (value, key, object, rootObject) => {
        //     if (typeof value === 'string') {
        //       object[key] = this.jsf.parseText(value, value, rootObject, key);
        //     }
        //   }, 'top-down');
        // }
        // // TODO: Figure out how to display calculated values without changing object data
        // // See http://ulion.github.io/jsonform/playground/?example=templating-values

        // TODO: (re-)render the form

        // Subscribe to form changes to output live data, validation, and errors
        this.jsf.dataChanges.subscribe(data => this.onChanges.emit(data));
        this.jsf.isValidChanges.subscribe(isValid => this.isValid.emit(isValid));
        this.jsf.validationErrorChanges.subscribe(errors => this.validationErrors.emit(errors));

        // Output final schema, final layout, and initial data
        this.formSchema.emit(this.jsf.schema);
        this.formLayout.emit(this.jsf.layout);
        this.onChanges.emit(this.jsf.data);

        // If 'validateOnRender' = true, output initial validation and any errors
        if (JsonPointer.get(this.jsf, '/globalOptions/validateOnRender')) {
          this.isValid.emit(this.jsf.isValid);
          this.validationErrors.emit(this.jsf.validationErrors);
        }

// Uncomment individual lines to output debugging information to console:
// (These always work.)
// console.log('loading form...');
// console.log(this.jsf.schema);
// console.log(this.jsf.layout);
// console.log(this.jsf.initialValues);
// console.log(this.jsf.formGroup.value);
// console.log(this.jsf.formGroupTemplate);
// console.log(this.jsf.formGroup);
// console.log(this.jsf.schemaRefLibrary);
// console.log(this.jsf.layoutRefLibrary);
// console.log(this.jsf.templateRefLibrary);
// console.log(this.jsf.dataMap);
// console.log(this.jsf.arrayMap);
// console.log(this.jsf.schemaRecursiveRefMap);
// console.log(this.jsf.dataRecursiveRefMap);
      } else {
        // TODO: Display error message
      }
    }
  }

  // Uncomment individual lines to output debugging information to browser:
  // (These only work if the 'debug' option has also been set to 'true'.)
  ngDoCheck() {
    if (this.debug || this.jsf.globalOptions.debug) {
      const vars: any[] = [];
      // vars.push(this.jsf.schema);
      // vars.push(this.jsf.layout);
      // vars.push(this.jsf.initialValues);
      // vars.push(this.jsf.formGroup.value);
      // vars.push(this.jsf.formGroupTemplate);
      // vars.push(this.jsf.formGroup);
      // vars.push(this.jsf.schemaRefLibrary);
      // vars.push(this.jsf.layoutRefLibrary);
      // vars.push(this.jsf.templateRefLibrary);
      // vars.push(this.jsf.dataMap);
      // vars.push(this.jsf.arrayMap);
      // vars.push(this.jsf.schemaRecursiveRefMap);
      // vars.push(this.jsf.dataRecursiveRefMap);
      this.debugOutput = vars.map(v => JSON.stringify(v, null, 2)).join('\n');
    }
  }

  private submitForm() {
    this.onSubmit.emit(this.jsf.validData);
  }
}