use std::sync::Arc;

use crate::agent::{AgentError, AgentLoop, CompositeSystemPromptProvider, SystemPromptProvider};
use crate::config::LLMProviderConfig;
use crate::experts::ExpertPromptProvider;
use crate::experts::ExpertRuntime;
use crate::gateway::agent_prompt_provider::AgentPromptProvider;
use crate::gateway::tool_prompt_provider::ToolPromptProvider;
use crate::skills::{SkillPromptProvider, SkillRuntime};
use crate::storage::persistent_session_id;
use crate::storage::PromptInjectionRepository;
use crate::tools::task::runtime::{SubagentPromptProvider, SubagentRuntime};
use crate::tools::{ToolContext, ToolRegistry};

/// 构建与 Agent 实际使用的完全一致的组合系统提示词 Provider。
///
/// 单一来源：AgentFactory::create 与命令侧（/save、/save-session、/current）
/// 都调用此函数，确保保存到文件的系统提示词与 LLM 实际接收的提示词一致。
///
/// Provider 顺序：AgentPrompt → SkillPrompt → ExpertPrompt → SubagentPrompt → TodoPrompt
pub(crate) fn build_system_prompt_provider(
    reinject_every: usize,
    provider_config: LLMProviderConfig,
    prompt_repository: Arc<dyn PromptInjectionRepository>,
    skills: Arc<SkillRuntime>,
    experts: Arc<ExpertRuntime>,
    subagent_runtime: Arc<SubagentRuntime>,
) -> Arc<dyn SystemPromptProvider> {
    Arc::new(CompositeSystemPromptProvider::new(vec![
        Box::new(AgentPromptProvider::new(
            reinject_every,
            provider_config,
            prompt_repository,
        )),
        Box::new(SkillPromptProvider::new(skills)),
        Box::new(ExpertPromptProvider::new(experts)),
        Box::new(SubagentPromptProvider::new(subagent_runtime)),
        Box::new(ToolPromptProvider::new()),
    ]))
}

#[derive(Clone)]
pub(crate) struct AgentFactory {
    tools: Arc<ToolRegistry>,
    skills: Arc<SkillRuntime>,
    experts: Arc<ExpertRuntime>,
    subagent_runtime: Arc<SubagentRuntime>,
    reinject_every: usize,
    prompt_repository: Arc<dyn PromptInjectionRepository>,
    /// 实例创建时间戳（用于区分新旧 AgentFactory 实例）
    instance_id: u64,
}

pub(crate) struct AgentBuildRequest<'a> {
    pub(crate) channel_name: &'a str,
    pub(crate) session_chat_id: &'a str,
    pub(crate) notification_chat_id: Option<&'a str>,
    pub(crate) sender_id: Option<&'a str>,
    pub(crate) message_id: Option<&'a str>,
    pub(crate) provider_config: LLMProviderConfig,
    /// 当前话题 ID（可选）：用于 todo 等按 topic 隔离的工具
    pub(crate) topic_id: Option<String>,
    /// 取消信号接收端（可选）：Agent 在每次迭代时检查是否被取消
    pub(crate) cancel_token: Option<tokio::sync::watch::Receiver<()>>,
}

impl AgentFactory {
    pub(crate) fn new(
        tools: Arc<ToolRegistry>,
        skills: Arc<SkillRuntime>,
        experts: Arc<ExpertRuntime>,
        subagent_runtime: Arc<SubagentRuntime>,
        reinject_every: usize,
        prompt_repository: Arc<dyn PromptInjectionRepository>,
    ) -> Self {
        // 使用 Arc 指针地址作为实例标识符，用于区分新旧 AgentFactory 实例
        let instance_id = Arc::as_ptr(&tools) as u64;
        tracing::info!(
            instance_id = instance_id,
            tool_count = tools.tool_names().len(),
            "AgentFactory::new created"
        );
        Self {
            tools,
            skills,
            experts,
            subagent_runtime,
            reinject_every,
            prompt_repository,
            instance_id,
        }
    }

    pub(crate) fn create(&self, request: AgentBuildRequest<'_>) -> Result<AgentLoop, AgentError> {
        let session_id = persistent_session_id(request.channel_name, request.session_chat_id);

        // 诊断日志：记录 agent 实际使用的配置和实例 ID
        tracing::info!(
            instance_id = self.instance_id,
            channel = %request.channel_name,
            session_id = %session_id,
            provider = %request.provider_config.name,
            model_id = %request.provider_config.model_id,
            tool_count = self.tools.tool_names().len(),
            "AgentFactory: creating agent with config"
        );

        // 创建组合的系统提示词提供者（与命令侧 /save 等共享同一构建逻辑）
        let system_prompt_provider = build_system_prompt_provider(
            self.reinject_every,
            request.provider_config.clone(),
            self.prompt_repository.clone(),
            self.skills.clone(),
            self.experts.clone(),
            self.subagent_runtime.clone(),
        );

        AgentLoop::with_tools_and_system_prompt_provider(
            request.provider_config,
            self.tools.clone(),
            system_prompt_provider,
            Some(self.skills.clone()),
        )
        .map(|agent| {
            // notification_chat_id 优先，否则使用 session_chat_id
            let tool_chat_id = request
                .notification_chat_id
                .unwrap_or(request.session_chat_id);
            let mut agent = agent.with_tool_context(ToolContext {
                channel_name: Some(request.channel_name.to_string()),
                sender_id: request.sender_id.map(str::to_string),
                chat_id: Some(tool_chat_id.to_string()),
                session_id: Some(session_id),
                topic_id: request.topic_id.clone(),
                message_id: request.message_id.map(str::to_string),
                message_seq: None,
                subagent_description: None,
                nesting_depth: 0,
                task_id: None,
                parent_task_id: None,
                tool_call_id: None,
            });
            // 如果有取消信号接收端，注入 Agent
            if let Some(token) = request.cancel_token {
                agent = agent.with_cancel_token(token);
            }
            agent
        })
    }
}