import * as plugins from './npmextra.plugins.js';
import { KeyValueStore } from './npmextra.classes.keyvaluestore.js';

// ============================================================================
// Singleton Qenv Provider
// ============================================================================
let sharedQenv: plugins.qenv.Qenv | undefined;

function getQenv(): plugins.qenv.Qenv {
  if (!sharedQenv) {
    sharedQenv = new plugins.qenv.Qenv(
      process.cwd(),
      plugins.path.join(process.cwd(), '.nogit')
    );
  }
  return sharedQenv;
}

// ============================================================================
// Type Converters - Centralized conversion logic
// ============================================================================
function toBoolean(value: unknown): boolean {
  if (typeof value === 'boolean') return value;
  if (value == null) return false;
  const s = String(value).toLowerCase();
  return s === 'true';
}

function toJson<T = any>(value: unknown): T | undefined {
  if (value == null) return undefined;
  if (typeof value === 'string') {
    try {
      return JSON.parse(value);
    } catch {
      return undefined;
    }
  }
  return value as T;
}

function fromBase64(value: unknown): string | undefined {
  if (value == null) return undefined;
  try {
    return Buffer.from(String(value), 'base64').toString('utf8');
  } catch {
    return String(value);
  }
}

function toNumber(value: unknown): number | undefined {
  if (value == null) return undefined;
  const num = Number(value);
  return Number.isNaN(num) ? undefined : num;
}

function toString(value: unknown): string | undefined {
  if (value == null) return undefined;
  return String(value);
}

// ============================================================================
// Declarative Pipeline Architecture
// ============================================================================
type Transform = 'boolean' | 'json' | 'base64' | 'number';

type MappingSpec = {
  source: 
    | { type: 'env'; key: string }
    | { type: 'hard'; value: string };
  transforms: Transform[];
};

// Transform registry for extensibility
const transformRegistry: Record<string, (v: unknown) => unknown> = {
  boolean: toBoolean,
  json: toJson,
  base64: fromBase64,
  number: toNumber,
};

/**
 * Parse a mapping string into a declarative spec
 */
function parseMappingSpec(input: string): MappingSpec {
  const transforms: Transform[] = [];
  let remaining = input;
  
  // Check for hardcoded prefixes with type conversion
  if (remaining.startsWith('hard_boolean:')) {
    return {
      source: { type: 'hard', value: remaining.slice(13) },
      transforms: ['boolean']
    };
  }
  
  if (remaining.startsWith('hard_json:')) {
    return {
      source: { type: 'hard', value: remaining.slice(10) },
      transforms: ['json']
    };
  }
  
  if (remaining.startsWith('hard_base64:')) {
    return {
      source: { type: 'hard', value: remaining.slice(12) },
      transforms: ['base64']
    };
  }
  
  // Check for generic hard: prefix
  if (remaining.startsWith('hard:')) {
    remaining = remaining.slice(5);
    // Check for legacy suffixes on hardcoded values
    if (remaining.endsWith('_JSON')) {
      transforms.push('json');
      remaining = remaining.slice(0, -5);
    } else if (remaining.endsWith('_BASE64')) {
      transforms.push('base64');
      remaining = remaining.slice(0, -7);
    }
    return {
      source: { type: 'hard', value: remaining },
      transforms
    };
  }
  
  // Check for env var prefixes
  if (remaining.startsWith('boolean:')) {
    transforms.push('boolean');
    remaining = remaining.slice(8);
  } else if (remaining.startsWith('json:')) {
    transforms.push('json');
    remaining = remaining.slice(5);
  } else if (remaining.startsWith('base64:')) {
    transforms.push('base64');
    remaining = remaining.slice(7);
  }
  
  // Check for legacy suffixes on env vars
  if (remaining.endsWith('_JSON')) {
    transforms.push('json');
    remaining = remaining.slice(0, -5);
  } else if (remaining.endsWith('_BASE64')) {
    transforms.push('base64');
    remaining = remaining.slice(0, -7);
  }
  
  return {
    source: { type: 'env', key: remaining },
    transforms
  };
}

/**
 * Resolve the source value (env var or hardcoded)
 */
async function resolveSource(source: MappingSpec['source']): Promise<unknown> {
  if (source.type === 'hard') {
    return source.value;
  }
  // source.type === 'env'
  return await getQenv().getEnvVarOnDemand(source.key);
}

/**
 * Apply transformations in sequence
 */
function applyTransforms(value: unknown, transforms: Transform[]): unknown {
  return transforms.reduce((acc, transform) => {
    const fn = transformRegistry[transform];
    return fn ? fn(acc) : acc;
  }, value);
}

/**
 * Process a mapping value through the complete pipeline
 */
async function processMappingValue(mappingString: string): Promise<unknown> {
  const spec = parseMappingSpec(mappingString);
  const rawValue = await resolveSource(spec.source);
  
  if (rawValue === undefined || rawValue === null) {
    return undefined;
  }
  
  return applyTransforms(rawValue, spec.transforms);
}

/**
 * Recursively evaluate mapping values (strings or nested objects)
 */
async function evaluateMappingValue(mappingValue: any): Promise<any> {
  if (typeof mappingValue === 'string') {
    return processMappingValue(mappingValue);
  }
  
  if (mappingValue && typeof mappingValue === 'object' && !Array.isArray(mappingValue)) {
    const result: any = {};
    for (const [key, value] of Object.entries(mappingValue)) {
      result[key] = await evaluateMappingValue(value);
    }
    return result;
  }
  
  return undefined;
}

// ============================================================================
// AppData Interface and Class
// ============================================================================
export interface IAppDataOptions<T = any> {
  dirPath?: string;
  requiredKeys?: Array<keyof T>;

  /**
   * Whether keys should be persisted on disk or not
   */
  ephemeral?: boolean;
  
  /**
   * @deprecated Use 'ephemeral' instead
   */
  ephermal?: boolean;

  /**
   * kvStoreKey: 'MY_ENV_VAR'
   */
  envMapping?: plugins.tsclass.typeFest.PartialDeep<T>;
  overwriteObject?: plugins.tsclass.typeFest.PartialDeep<T>;
}

export class AppData<T = any> {
  /**
   * creates appdata. If no pathArg is given, data will be stored here:
   * ${PWD}/.nogit/appdata
   * @param pathArg
   * @returns
   */
  public static async createAndInit<T = any>(
    optionsArg: IAppDataOptions<T> = {},
  ): Promise<AppData<T>> {
    const appData = new AppData<T>(optionsArg);
    await appData.readyDeferred.promise;
    return appData;
  }

  /**
   * Static helper to get an environment variable as a boolean
   * @param envVarName The name of the environment variable
   * @returns boolean value (true if env var is "true", false otherwise)
   */
  public static async valueAsBoolean(envVarName: string): Promise<boolean> {
    const value = await getQenv().getEnvVarOnDemand(envVarName);
    return toBoolean(value);
  }

  /**
   * Static helper to get an environment variable as parsed JSON
   * @param envVarName The name of the environment variable
   * @returns Parsed JSON object/array
   */
  public static async valueAsJson<R = any>(envVarName: string): Promise<R | undefined> {
    const value = await getQenv().getEnvVarOnDemand(envVarName);
    return toJson<R>(value);
  }

  /**
   * Static helper to get an environment variable as base64 decoded string
   * @param envVarName The name of the environment variable
   * @returns Decoded string
   */
  public static async valueAsBase64(envVarName: string): Promise<string | undefined> {
    const value = await getQenv().getEnvVarOnDemand(envVarName);
    return fromBase64(value);
  }

  /**
   * Static helper to get an environment variable as a string
   * @param envVarName The name of the environment variable
   * @returns String value
   */
  public static async valueAsString(envVarName: string): Promise<string | undefined> {
    const value = await getQenv().getEnvVarOnDemand(envVarName);
    return toString(value);
  }

  /**
   * Static helper to get an environment variable as a number
   * @param envVarName The name of the environment variable
   * @returns Number value
   */
  public static async valueAsNumber(envVarName: string): Promise<number | undefined> {
    const value = await getQenv().getEnvVarOnDemand(envVarName);
    return toNumber(value);
  }

  // instance
  public readyDeferred = plugins.smartpromise.defer<void>();
  public options: IAppDataOptions<T>;
  private kvStore: KeyValueStore<T>;

  constructor(optionsArg: IAppDataOptions<T> = {}) {
    this.options = optionsArg;
    this.init();
  }

  /**
   * inits app data
   */
  private async init() {
    console.log('🚀 Initializing AppData...');
    
    // Handle backward compatibility for typo
    const isEphemeral = this.options.ephemeral ?? this.options.ephermal ?? false;
    if (this.options.ephermal && !this.options.ephemeral) {
      console.warn('⚠️ Option "ephermal" is deprecated, use "ephemeral" instead.');
    }
    
    if (this.options.dirPath) {
      console.log(`  📁 Using custom directory: ${this.options.dirPath}`);
    } else if (isEphemeral) {
      console.log(`  💨 Using ephemeral storage (in-memory only)`);
    } else {
      const appDataDir = '/app/data';
      const dataDir = '/data';
      const nogitAppData = '.nogit/appdata';
      const appDataExists = plugins.smartfile.fs.isDirectory(appDataDir);
      const dataExists = plugins.smartfile.fs.isDirectory(dataDir);
      if (appDataExists) {
        this.options.dirPath = appDataDir;
        console.log(`  📁 Auto-selected container directory: ${appDataDir}`);
      } else if (dataExists) {
        this.options.dirPath = dataDir;
        console.log(`  📁 Auto-selected data directory: ${dataDir}`);
      } else {
        await plugins.smartfile.fs.ensureDir(nogitAppData);
        this.options.dirPath = nogitAppData;
        console.log(`  📁 Auto-selected local directory: ${nogitAppData}`);
      }
    }

    this.kvStore = new KeyValueStore<T>({
      typeArg: isEphemeral ? 'ephemeral' : 'custom',
      identityArg: 'appkv',
      customPath: this.options.dirPath,
      mandatoryKeys: this.options.requiredKeys as Array<keyof T>,
    });

    if (this.options.envMapping) {
      console.log(`📦 Processing envMapping for AppData...`);
      const totalKeys = Object.keys(this.options.envMapping).length;
      let processedCount = 0;
      
      // Process each top-level key in envMapping
      for (const key in this.options.envMapping) {
        try {
          const mappingSpec = this.options.envMapping[key];
          console.log(`  → Processing key "${key}" with spec:`, typeof mappingSpec === 'string' ? mappingSpec : 'nested object');
          
          const evaluated = await evaluateMappingValue(mappingSpec);
          if (evaluated !== undefined) {
            await this.kvStore.writeKey(key as keyof T, evaluated);
            processedCount++;
            const valueType = Array.isArray(evaluated) ? 'array' : typeof evaluated;
            console.log(`  ✅ Successfully processed key "${key}" (type: ${valueType})`);
          } else {
            console.log(`  ⚠️ Key "${key}" evaluated to undefined, skipping`);
          }
        } catch (err) {
          console.error(`  ❌ Failed to evaluate envMapping for key "${key}":`, err);
        }
      }
      
      console.log(`📊 EnvMapping complete: ${processedCount}/${totalKeys} keys successfully processed`);
    }

    // Apply overwrite object after env mapping
    if (this.options.overwriteObject) {
      const overwriteKeys = Object.keys(this.options.overwriteObject);
      console.log(`🔄 Applying overwriteObject with ${overwriteKeys.length} key(s)...`);
      
      for (const key of overwriteKeys) {
        const value = this.options.overwriteObject[key];
        const valueType = Array.isArray(value) ? 'array' : typeof value;
        console.log(`  🔧 Overwriting key "${key}" with ${valueType} value`);
        
        await this.kvStore.writeKey(
          key as keyof T,
          value,
        );
      }
      
      console.log(`✅ OverwriteObject complete: ${overwriteKeys.length} key(s) overwritten`);
    }

    this.readyDeferred.resolve();
    console.log('✨ AppData initialization complete!');
  }

  /**
   * returns a kvstore that resides in appdata
   */
  public async getKvStore(): Promise<KeyValueStore<T>> {
    await this.readyDeferred.promise;
    return this.kvStore;
  }

  public async logMissingKeys(): Promise<Array<keyof T>> {
    const kvStore = await this.getKvStore();
    const missingMandatoryKeys = await kvStore.getMissingMandatoryKeys();
    if (missingMandatoryKeys.length > 0) {
      console.log(
        `The following mandatory keys are missing in the appdata:\n   -> ${missingMandatoryKeys.join(
          ',\n   -> ',
        )}`,
      );
    } else {
      console.log('All mandatory keys are present in the appdata');
    }
    return missingMandatoryKeys;
  }

  public async waitForAndGetKey<K extends keyof T>(
    keyArg: K,
  ): Promise<T[K] | undefined> {
    await this.readyDeferred.promise;
    await this.kvStore.waitForKeysPresent([keyArg]);
    return this.kvStore.readKey(keyArg);
  }
}