/**
 * V3 Plugin Registry
 * Domain-Driven Design - Plugin-Based Architecture (ADR-004)
 *
 * Central registry for tracking plugin state, metadata, and registrations
 */

import type {
  ClaudeFlowPlugin,
  PluginInfo,
  PluginLifecycleState,
  PluginContext,
  AgentTypeDefinition,
  TaskTypeDefinition,
  MCPToolDefinition,
  CLICommandDefinition,
  MemoryBackendFactory,
} from './plugin-interface.js';
import { PluginError } from './plugin-interface.js';

/**
 * Plugin registry for managing plugin lifecycle and registrations
 */
export class PluginRegistry {
  private plugins = new Map<string, PluginInfo>();
  private agentTypes = new Map<string, { plugin: string; definition: AgentTypeDefinition }>();
  private taskTypes = new Map<string, { plugin: string; definition: TaskTypeDefinition }>();
  private mcpTools = new Map<string, { plugin: string; definition: MCPToolDefinition }>();
  private cliCommands = new Map<string, { plugin: string; definition: CLICommandDefinition }>();
  private memoryBackends = new Map<string, { plugin: string; factory: MemoryBackendFactory }>();

  /**
   * Register a plugin in the registry
   */
  registerPlugin(
    plugin: ClaudeFlowPlugin,
    initialState: PluginLifecycleState,
    context: PluginContext
  ): void {
    if (this.plugins.has(plugin.name)) {
      throw new PluginError(
        `Plugin '${plugin.name}' is already registered`,
        plugin.name,
        'DUPLICATE_PLUGIN'
      );
    }

    const info: PluginInfo = {
      plugin,
      state: initialState,
      context,
      metrics: {
        agentTypesRegistered: 0,
        taskTypesRegistered: 0,
        mcpToolsRegistered: 0,
        cliCommandsRegistered: 0,
        memoryBackendsRegistered: 0,
      },
    };

    this.plugins.set(plugin.name, info);
  }

  /**
   * Unregister a plugin from the registry
   */
  unregisterPlugin(pluginName: string): boolean {
    const info = this.plugins.get(pluginName);
    if (!info) {
      return false;
    }

    // Unregister all plugin's registrations
    this.unregisterPluginAgentTypes(pluginName);
    this.unregisterPluginTaskTypes(pluginName);
    this.unregisterPluginMCPTools(pluginName);
    this.unregisterPluginCLICommands(pluginName);
    this.unregisterPluginMemoryBackends(pluginName);

    // Remove plugin
    return this.plugins.delete(pluginName);
  }

  /**
   * Get a plugin by name
   */
  getPlugin(pluginName: string): PluginInfo | undefined {
    return this.plugins.get(pluginName);
  }

  /**
   * Get all registered plugins
   */
  getAllPlugins(): Map<string, PluginInfo> {
    return new Map(this.plugins);
  }

  /**
   * Get all plugin names
   */
  getPluginNames(): string[] {
    return Array.from(this.plugins.keys());
  }

  /**
   * Check if a plugin is registered
   */
  hasPlugin(pluginName: string): boolean {
    return this.plugins.has(pluginName);
  }

  /**
   * Get plugins by state
   */
  getPluginsByState(state: PluginLifecycleState): PluginInfo[] {
    return Array.from(this.plugins.values()).filter((info) => info.state === state);
  }

  /**
   * Get plugin count
   */
  getPluginCount(): number {
    return this.plugins.size;
  }

  /**
   * Update plugin state
   */
  updatePluginState(pluginName: string, state: PluginLifecycleState, error?: Error): void {
    const info = this.plugins.get(pluginName);
    if (!info) {
      throw new PluginError(
        `Plugin '${pluginName}' not found`,
        pluginName,
        'INVALID_PLUGIN'
      );
    }

    info.state = state;

    if (state === 'initialized') {
      info.initializedAt = new Date();
    } else if (state === 'shutdown') {
      info.shutdownAt = new Date();
    } else if (state === 'error') {
      info.error = error;
    }
  }

  /**
   * Collect and update plugin metrics
   */
  collectPluginMetrics(pluginName: string): void {
    const info = this.plugins.get(pluginName);
    if (!info || !info.metrics) {
      return;
    }

    const plugin = info.plugin;

    // Count registered items
    info.metrics.agentTypesRegistered = plugin.registerAgentTypes?.()?.length || 0;
    info.metrics.taskTypesRegistered = plugin.registerTaskTypes?.()?.length || 0;
    info.metrics.mcpToolsRegistered = plugin.registerMCPTools?.()?.length || 0;
    info.metrics.cliCommandsRegistered = plugin.registerCLICommands?.()?.length || 0;
    info.metrics.memoryBackendsRegistered = plugin.registerMemoryBackends?.()?.length || 0;
  }

  /**
   * Get plugin status summary
   */
  getStatusSummary(): PluginRegistryStatus {
    const states = Array.from(this.plugins.values()).reduce((acc, info) => {
      acc[info.state] = (acc[info.state] || 0) + 1;
      return acc;
    }, {} as Record<PluginLifecycleState, number>);

    return {
      totalPlugins: this.plugins.size,
      states,
      agentTypesRegistered: this.agentTypes.size,
      taskTypesRegistered: this.taskTypes.size,
      mcpToolsRegistered: this.mcpTools.size,
      cliCommandsRegistered: this.cliCommands.size,
      memoryBackendsRegistered: this.memoryBackends.size,
    };
  }

  // =============================================================================
  // Agent Type Registry
  // =============================================================================

  /**
   * Register agent types from a plugin
   */
  registerAgentTypes(pluginName: string): void {
    const info = this.plugins.get(pluginName);
    if (!info) {
      throw new PluginError(
        `Plugin '${pluginName}' not found`,
        pluginName,
        'INVALID_PLUGIN'
      );
    }

    const agentTypes = info.plugin.registerAgentTypes?.();
    if (!agentTypes || agentTypes.length === 0) {
      return;
    }

    for (const definition of agentTypes) {
      if (this.agentTypes.has(definition.type)) {
        throw new PluginError(
          `Agent type '${definition.type}' is already registered by plugin '${this.agentTypes.get(definition.type)?.plugin}'`,
          pluginName,
          'DUPLICATE_PLUGIN'
        );
      }

      this.agentTypes.set(definition.type, { plugin: pluginName, definition });
    }
  }

  /**
   * Unregister agent types from a plugin
   */
  unregisterPluginAgentTypes(pluginName: string): void {
    for (const [type, entry] of Array.from(this.agentTypes.entries())) {
      if (entry.plugin === pluginName) {
        this.agentTypes.delete(type);
      }
    }
  }

  /**
   * Get agent type definition
   */
  getAgentType(type: string): AgentTypeDefinition | undefined {
    return this.agentTypes.get(type)?.definition;
  }

  /**
   * Get all agent types
   */
  getAllAgentTypes(): AgentTypeDefinition[] {
    return Array.from(this.agentTypes.values()).map((entry) => entry.definition);
  }

  /**
   * Get agent types by plugin
   */
  getAgentTypesByPlugin(pluginName: string): AgentTypeDefinition[] {
    return Array.from(this.agentTypes.values())
      .filter((entry) => entry.plugin === pluginName)
      .map((entry) => entry.definition);
  }

  // =============================================================================
  // Task Type Registry
  // =============================================================================

  /**
   * Register task types from a plugin
   */
  registerTaskTypes(pluginName: string): void {
    const info = this.plugins.get(pluginName);
    if (!info) {
      throw new PluginError(
        `Plugin '${pluginName}' not found`,
        pluginName,
        'INVALID_PLUGIN'
      );
    }

    const taskTypes = info.plugin.registerTaskTypes?.();
    if (!taskTypes || taskTypes.length === 0) {
      return;
    }

    for (const definition of taskTypes) {
      if (this.taskTypes.has(definition.type)) {
        throw new PluginError(
          `Task type '${definition.type}' is already registered by plugin '${this.taskTypes.get(definition.type)?.plugin}'`,
          pluginName,
          'DUPLICATE_PLUGIN'
        );
      }

      this.taskTypes.set(definition.type, { plugin: pluginName, definition });
    }
  }

  /**
   * Unregister task types from a plugin
   */
  unregisterPluginTaskTypes(pluginName: string): void {
    for (const [type, entry] of Array.from(this.taskTypes.entries())) {
      if (entry.plugin === pluginName) {
        this.taskTypes.delete(type);
      }
    }
  }

  /**
   * Get task type definition
   */
  getTaskType(type: string): TaskTypeDefinition | undefined {
    return this.taskTypes.get(type)?.definition;
  }

  /**
   * Get all task types
   */
  getAllTaskTypes(): TaskTypeDefinition[] {
    return Array.from(this.taskTypes.values()).map((entry) => entry.definition);
  }

  /**
   * Get task types by plugin
   */
  getTaskTypesByPlugin(pluginName: string): TaskTypeDefinition[] {
    return Array.from(this.taskTypes.values())
      .filter((entry) => entry.plugin === pluginName)
      .map((entry) => entry.definition);
  }

  // =============================================================================
  // MCP Tool Registry
  // =============================================================================

  /**
   * Register MCP tools from a plugin
   */
  registerMCPTools(pluginName: string): void {
    const info = this.plugins.get(pluginName);
    if (!info) {
      throw new PluginError(
        `Plugin '${pluginName}' not found`,
        pluginName,
        'INVALID_PLUGIN'
      );
    }

    const mcpTools = info.plugin.registerMCPTools?.();
    if (!mcpTools || mcpTools.length === 0) {
      return;
    }

    for (const definition of mcpTools) {
      if (this.mcpTools.has(definition.name)) {
        throw new PluginError(
          `MCP tool '${definition.name}' is already registered by plugin '${this.mcpTools.get(definition.name)?.plugin}'`,
          pluginName,
          'DUPLICATE_PLUGIN'
        );
      }

      // Add plugin metadata
      definition.pluginName = pluginName;

      this.mcpTools.set(definition.name, { plugin: pluginName, definition });
    }
  }

  /**
   * Unregister MCP tools from a plugin
   */
  unregisterPluginMCPTools(pluginName: string): void {
    for (const [name, entry] of Array.from(this.mcpTools.entries())) {
      if (entry.plugin === pluginName) {
        this.mcpTools.delete(name);
      }
    }
  }

  /**
   * Get MCP tool definition
   */
  getMCPTool(name: string): MCPToolDefinition | undefined {
    return this.mcpTools.get(name)?.definition;
  }

  /**
   * Get all MCP tools
   */
  getAllMCPTools(): MCPToolDefinition[] {
    return Array.from(this.mcpTools.values()).map((entry) => entry.definition);
  }

  /**
   * Get MCP tools by plugin
   */
  getMCPToolsByPlugin(pluginName: string): MCPToolDefinition[] {
    return Array.from(this.mcpTools.values())
      .filter((entry) => entry.plugin === pluginName)
      .map((entry) => entry.definition);
  }

  // =============================================================================
  // CLI Command Registry
  // =============================================================================

  /**
   * Register CLI commands from a plugin
   */
  registerCLICommands(pluginName: string): void {
    const info = this.plugins.get(pluginName);
    if (!info) {
      throw new PluginError(
        `Plugin '${pluginName}' not found`,
        pluginName,
        'INVALID_PLUGIN'
      );
    }

    const cliCommands = info.plugin.registerCLICommands?.();
    if (!cliCommands || cliCommands.length === 0) {
      return;
    }

    for (const definition of cliCommands) {
      if (this.cliCommands.has(definition.name)) {
        throw new PluginError(
          `CLI command '${definition.name}' is already registered by plugin '${this.cliCommands.get(definition.name)?.plugin}'`,
          pluginName,
          'DUPLICATE_PLUGIN'
        );
      }

      this.cliCommands.set(definition.name, { plugin: pluginName, definition });

      // Register aliases
      if (definition.aliases) {
        for (const alias of definition.aliases) {
          if (this.cliCommands.has(alias)) {
            throw new PluginError(
              `CLI command alias '${alias}' is already registered`,
              pluginName,
              'DUPLICATE_PLUGIN'
            );
          }
          this.cliCommands.set(alias, { plugin: pluginName, definition });
        }
      }
    }
  }

  /**
   * Unregister CLI commands from a plugin
   */
  unregisterPluginCLICommands(pluginName: string): void {
    for (const [name, entry] of Array.from(this.cliCommands.entries())) {
      if (entry.plugin === pluginName) {
        this.cliCommands.delete(name);
      }
    }
  }

  /**
   * Get CLI command definition
   */
  getCLICommand(name: string): CLICommandDefinition | undefined {
    return this.cliCommands.get(name)?.definition;
  }

  /**
   * Get all CLI commands
   */
  getAllCLICommands(): CLICommandDefinition[] {
    const seen = new Set<CLICommandDefinition>();
    return Array.from(this.cliCommands.values())
      .map((entry) => entry.definition)
      .filter((def) => {
        if (seen.has(def)) return false;
        seen.add(def);
        return true;
      });
  }

  /**
   * Get CLI commands by plugin
   */
  getCLICommandsByPlugin(pluginName: string): CLICommandDefinition[] {
    const seen = new Set<CLICommandDefinition>();
    return Array.from(this.cliCommands.values())
      .filter((entry) => entry.plugin === pluginName)
      .map((entry) => entry.definition)
      .filter((def) => {
        if (seen.has(def)) return false;
        seen.add(def);
        return true;
      });
  }

  // =============================================================================
  // Memory Backend Registry
  // =============================================================================

  /**
   * Register memory backends from a plugin
   */
  registerMemoryBackends(pluginName: string): void {
    const info = this.plugins.get(pluginName);
    if (!info) {
      throw new PluginError(
        `Plugin '${pluginName}' not found`,
        pluginName,
        'INVALID_PLUGIN'
      );
    }

    const memoryBackends = info.plugin.registerMemoryBackends?.();
    if (!memoryBackends || memoryBackends.length === 0) {
      return;
    }

    for (const factory of memoryBackends) {
      if (this.memoryBackends.has(factory.name)) {
        throw new PluginError(
          `Memory backend '${factory.name}' is already registered by plugin '${this.memoryBackends.get(factory.name)?.plugin}'`,
          pluginName,
          'DUPLICATE_PLUGIN'
        );
      }

      this.memoryBackends.set(factory.name, { plugin: pluginName, factory });
    }
  }

  /**
   * Unregister memory backends from a plugin
   */
  unregisterPluginMemoryBackends(pluginName: string): void {
    for (const [name, entry] of Array.from(this.memoryBackends.entries())) {
      if (entry.plugin === pluginName) {
        this.memoryBackends.delete(name);
      }
    }
  }

  /**
   * Get memory backend factory
   */
  getMemoryBackend(name: string): MemoryBackendFactory | undefined {
    return this.memoryBackends.get(name)?.factory;
  }

  /**
   * Get all memory backends
   */
  getAllMemoryBackends(): MemoryBackendFactory[] {
    return Array.from(this.memoryBackends.values()).map((entry) => entry.factory);
  }

  /**
   * Get memory backends by plugin
   */
  getMemoryBackendsByPlugin(pluginName: string): MemoryBackendFactory[] {
    return Array.from(this.memoryBackends.values())
      .filter((entry) => entry.plugin === pluginName)
      .map((entry) => entry.factory);
  }

  // =============================================================================
  // Bulk Registration
  // =============================================================================

  /**
   * Register all extension points from a plugin
   */
  registerAllFromPlugin(pluginName: string): void {
    this.registerAgentTypes(pluginName);
    this.registerTaskTypes(pluginName);
    this.registerMCPTools(pluginName);
    this.registerCLICommands(pluginName);
    this.registerMemoryBackends(pluginName);
    this.collectPluginMetrics(pluginName);
  }

  /**
   * Clear all registrations (for testing)
   */
  clear(): void {
    this.plugins.clear();
    this.agentTypes.clear();
    this.taskTypes.clear();
    this.mcpTools.clear();
    this.cliCommands.clear();
    this.memoryBackends.clear();
  }
}

/**
 * Plugin registry status summary
 */
export interface PluginRegistryStatus {
  totalPlugins: number;
  states: Record<PluginLifecycleState, number>;
  agentTypesRegistered: number;
  taskTypesRegistered: number;
  mcpToolsRegistered: number;
  cliCommandsRegistered: number;
  memoryBackendsRegistered: number;
}