import endent from 'endent';
import * as fs from 'fs';
import { JSONPgSmartTags } from 'graphile-utils';
import * as JSON5 from 'json5';
import * as path from 'path';
import {
  BaseSmartTags,
  PgColumn,
  PgFkColumn,
  PgTable,
  TableSmartTags,
} from '../abstractions';

/**
 * Builds smart tags for FK constraints.
 * @param columns - Array of FK columns.
 */
export function buildFkConstraintSmartTags(columns: PgFkColumn[]): {
  [name: string]: BaseSmartTags;
} {
  return columns.reduce((acc, col) => {
    if (col.fkName) {
      acc[col.fkName] = {
        tags: {
          foreignFieldName: `${col.table.displayName ?? col.table.name}`,
        },
      };
    }
    return acc;
  }, {} as { [name: string]: BaseSmartTags });
}

/**
 * Builds class (table) level smart tags.
 * @param tables - Array of tables.
 */
export function buildClassSmartTags(tables: PgTable[]): {
  [name: string]: TableSmartTags;
} {
  const tags: { [name: string]: TableSmartTags } = {};

  tables.forEach((t) => {
    tags[t.name] = t.buildSmartTags();
  });

  return tags;
}

/**
 * Builds smart tags for virtual FK columns.
 * @param virtualFks - Array of virtual FK columns.
 */
export function buildVirtualFkSmartTags(virtualFks: PgFkColumn[]): string[] {
  return virtualFks.map((vfk) => {
    return `(${vfk.name}) references ${vfk.targetPk.table.name}|@omit many`;
  });
}

/**
 * Builds attribute (column) level smart tags.
 * @param columns - Array of PgColumns.
 */
export function buildAttributeSmartTags(columns: PgColumn[]): {
  [name: string]: BaseSmartTags;
} {
  return columns.reduce((acc, col) => {
    acc[col.name] = col.buildSmartTags();
    return acc;
  }, {} as { [name: string]: BaseSmartTags });
}

// TODO: Replace with camelCase from graphile-build.
export function snakeCaseToCamelCase(input: string): string {
  return input
    .split('_')
    .reduce(
      (res, word, i) =>
        i === 0
          ? word.toLowerCase()
          : `${res}${word.charAt(0).toUpperCase()}${word
              .substr(1)
              .toLowerCase()}`,
      '',
    );
}

/**
 * Generates a smart tags plugin file.
 * @param tags - Smart tags configuration.
 * @param outPath - Output path where the plugin will be written.
 */
export function generateSmartTagsPlugin(
  tags: JSONPgSmartTags,
  outPath: string,
): void {
  const dirPath = path.dirname(outPath);
  if (!fs.existsSync(dirPath)) {
    fs.mkdirSync(dirPath, { recursive: true });
  }

  console.log(`Writing smart tags plugn to to ${outPath}.`);

  const pluginSrc = endent`
  import { makeJSONPgSmartTagsPlugin } from 'graphile-utils';
  /**
  * Smart tags to adjust and enhance the generated GraphQL API.
  */
  export const SmartTagsPlugin = makeJSONPgSmartTagsPlugin(${endent.pretty(
    // Use JSON5 to generate keys without quotes to make the generated code already compatible with prettier.
    JSON5.stringify(tags, null, 2),
  )});
  `;

  fs.writeFileSync(outPath, pluginSrc);
}