import { ConfigGetResult, ConfigListSummary, ConfigValues } from '../../../typings';
import { last, splitOn } from '../utils';

export class ConfigList implements ConfigListSummary {
   public files: string[] = [];
   public values: { [fileName: string]: ConfigValues } = Object.create(null);

   private _all: ConfigValues | undefined;

   public get all(): ConfigValues {
      if (!this._all) {
         this._all = this.files.reduce((all: ConfigValues, file: string) => {
            return Object.assign(all, this.values[file]);
         }, {});
      }

      return this._all;
   }

   public addFile(file: string): ConfigValues {
      if (!(file in this.values)) {
         const latest = last(this.files);
         this.values[file] = latest ? Object.create(this.values[latest]) : {};

         this.files.push(file);
      }

      return this.values[file];
   }

   public addValue(file: string, key: string, value: string) {
      const values = this.addFile(file);

      if (!Object.hasOwn(values, key)) {
         values[key] = value;
      } else if (Array.isArray(values[key])) {
         (values[key] as string[]).push(value);
      } else {
         values[key] = [values[key] as string, value];
      }

      this._all = undefined;
   }
}

export function configListParser(text: string): ConfigList {
   const config = new ConfigList();

   for (const item of configParser(text)) {
      config.addValue(item.file, String(item.key), item.value);
   }

   return config;
}

export function configGetParser(text: string, key: string): ConfigGetResult {
   let value: string | null = null;
   const values: string[] = [];
   const scopes: Map<string, string[]> = new Map();

   for (const item of configParser(text, key)) {
      if (item.key !== key) {
         continue;
      }

      values.push((value = item.value));

      if (!scopes.has(item.file)) {
         scopes.set(item.file, []);
      }

      scopes.get(item.file)!.push(value);
   }

   return {
      key,
      paths: Array.from(scopes.keys()),
      scopes,
      value,
      values,
   };
}

function configFilePath(filePath: string): string {
   return filePath.replace(/^(file):/, '');
}

function* configParser(text: string, requestedKey: string | null = null) {
   const lines = text.split('\0');

   for (let i = 0, max = lines.length - 1; i < max; ) {
      const file = configFilePath(lines[i++]);

      let value = lines[i++];
      let key = requestedKey;

      if (value.includes('\n')) {
         const line = splitOn(value, '\n');
         key = line[0];
         value = line[1];
      }

      yield { file, key, value };
   }
}