import { signal, Signal } from '@preact/signals-core';
import type { Command, CommandLogEntry, CommandExecutionResult, StepResult, QueuedCommand } from './Command';
import { CommandStatus } from './Command';

/**
 * 命令日志过滤器
 */
export interface CommandLogFilter {
  commandId?: string;
  success?: boolean;
  startTime?: number;
  endTime?: number;
}

/**
 * 命令日志类
 * 记录所有执行的命令及其结果
 */
export class CommandLog {
  /** 日志条目信号 */
  private entries: Signal<CommandLogEntry[]>;

  /** 待执行队列 */
  private queue: QueuedCommand[];

  constructor() {
    this.entries = signal<CommandLogEntry[]>([]);
    this.queue = [];
  }

  /**
   * 记录命令执行
   */
  log(
    command: Command,
    result: CommandExecutionResult,
    stepResults: StepResult[]
  ): void {
    const entry: CommandLogEntry = {
      timestamp: Date.now(),
      commandId: command.id,
      commandName: command.name,
      result,
      stepResults,
    };

    const current = this.entries.value;
    this.entries.value = [...current, entry];
  }

  /**
   * 获取所有日志条目
   */
  getEntries(): CommandLogEntry[] {
    return this.entries.value;
  }

  /**
   * 获取日志信号
   */
  getEntriesSignal(): Signal<CommandLogEntry[]> {
    return this.entries;
  }

  /**
   * 根据过滤器获取日志条目
   */
  getFilteredEntries(filter: CommandLogFilter): CommandLogEntry[] {
    return this.entries.value.filter((entry) => {
      if (filter.commandId && entry.commandId !== filter.commandId) {
        return false;
      }
      if (filter.success !== undefined && entry.result.success !== filter.success) {
        return false;
      }
      if (filter.startTime && entry.timestamp < filter.startTime) {
        return false;
      }
      if (filter.endTime && entry.timestamp > filter.endTime) {
        return false;
      }
      return true;
    });
  }

  /**
   * 获取命令的执行历史
   */
  getCommandHistory(commandId: string): CommandLogEntry[] {
    return this.getFilteredEntries({ commandId });
  }

  /**
   * 获取失败的命令
   */
  getFailedCommands(): CommandLogEntry[] {
    return this.getFilteredEntries({ success: false });
  }

  /**
   * 获取成功的命令
   */
  getSuccessfulCommands(): CommandLogEntry[] {
    return this.getFilteredEntries({ success: true });
  }

  /**
   * 清空日志
   */
  clear(): void {
    this.entries.value = [];
  }

  /**
   * 导出日志为 JSON
   */
  exportToJson(): string {
    return JSON.stringify(this.entries.value, null, 2);
  }

  /**
   * 获取日志条目数量
   */
  getCount(): number {
    return this.entries.value.length;
  }

  /**
   * 获取最后一个日志条目
   */
  getLastEntry(): CommandLogEntry | null {
    const entries = this.entries.value;
    return entries.length > 0 ? entries[entries.length - 1] : null;
  }

  // ========== 队列管理 ==========

  /**
   * 添加命令到队列
   */
  enqueue(command: Command): QueuedCommand {
    const queued: QueuedCommand = {
      id: command.id,
      command,
      status: CommandStatus.Pending,
      queuedAt: Date.now(),
    };
    this.queue.push(queued);
    return queued;
  }

  /**
   * 从队列中移除命令
   */
  dequeue(): QueuedCommand | null {
    if (this.queue.length === 0) {
      return null;
    }
    return this.queue.shift() || null;
  }

  /**
   * 获取队列中的所有命令
   */
  getQueue(): QueuedCommand[] {
    return [...this.queue];
  }

  /**
   * 更新队列中命令的状态
   */
  updateQueueStatus(commandId: string, status: CommandStatus, result?: CommandExecutionResult): void {
    const index = this.queue.findIndex((q) => q.command.id === commandId);
    if (index !== -1) {
      this.queue[index].status = status;
      if (status === CommandStatus.Completed || status === CommandStatus.Failed) {
        this.queue[index].executedAt = Date.now();
        this.queue[index].result = result;
      }
    }
  }

  /**
   * 清空队列
   */
  clearQueue(): void {
    this.queue = [];
  }

  /**
   * 获取队列长度
   */
  getQueueLength(): number {
    return this.queue.length;
  }
}

/**
 * 创建命令日志
 */
export function createCommandLog(): CommandLog {
  return new CommandLog();
}