//! 系统提示词构建 + 活跃提供商获取

use df_storage::models::AiProviderRecord;

use crate::state::AppState;

/// 获取当前活跃提供商配置
pub(crate) async fn get_active_provider(state: &AppState) -> Result<AiProviderRecord, String> {
    let session = state.ai_session.lock().await;
    if let Some(ref pid) = session.active_provider_id {
        let provider = state
            .ai_providers
            .get_by_id(pid)
            .await
            .map_err(|e| e.to_string())?
            .ok_or_else(|| format!("活跃提供商不存在: {}", pid))?;
        Ok(provider)
    } else {
        // 查找默认提供商
        drop(session);
        let providers = state
            .ai_providers
            .list_all()
            .await
            .map_err(|e| e.to_string())?;
        let default = providers.iter().find(|p| p.is_default).cloned();
        default
            .or_else(|| providers.into_iter().next())
            .ok_or_else(|| "未配置 AI 提供商，请先在设置中添加".to_string())
    }
}

/// 按语言返回系统提示词的 (固定前缀, 项目上下文标题)
fn system_prompt_parts(lang: &str) -> (&'static str, &'static str) {
    match lang {
        "en" => (
            "You are DevFlow's AI assistant. You help users manage projects, tasks, ideas, and workflows.\n\
             Please respond in English.\n\n\
             ## Capabilities\n\
             You can perform the following actions via tool calls:\n\
             - Create/query projects, tasks, and ideas\n\
             - Run workflows\n\
             - Read file contents, list directories, create/write files\n\n\
             ## Guidelines\n\
             - Briefly explain your intent before executing actions\n\
             - Ask for clarification if the user's intent is unclear\n\
             - Prefer using tools to complete actions rather than just describing steps\n\
             - When a tool call fails, clearly tell the user it failed and why. Never disguise a fallback action as the original intent's success (e.g. don't write to description to fake a directory binding), and never falsely report success\n",
            "\n## Current Projects\n",
        ),
        _ => (
            "你是 DevFlow 的 AI 助手。你帮助用户管理项目、任务、灵感和工作流。\n\
             必须使用简体中文回复，禁止使用繁体中文字符。\n\n\
             ## 当前能力\n\
             你可以通过工具调用执行以下操作：\n\
             - 创建/查询项目、任务、灵感\n\
             - 运行工作流\n\
             - 读取文件内容、列出目录、创建/写入文件\n\n\
             ## 行为准则\n\
             - 执行操作前简要说明你的意图\n\
             - 如果不确定用户意图，先提问\n\
             - 优先使用工具完成操作，而不是只描述步骤\n\
             - 工具调用失败时必须明确告知用户失败原因，严禁用替代操作冒充原意图成功（如绑定目录失败不得改写描述冒充已绑定），也绝不谎报成功\n",
            "\n## 当前项目\n",
        ),
    }
}

/// 构建系统提示词（固定前缀 + 当前项目上下文）
pub(crate) async fn build_system_prompt(state: &AppState, lang: &str) -> String {
    let (prefix, ctx_label) = system_prompt_parts(lang);
    let mut prompt = String::from(prefix);

    // 附加当前数据上下文
    if let Ok(projects) = state.projects.list_active().await {
        if !projects.is_empty() {
            prompt.push_str(ctx_label);
            // system prompt 前缀克制：仅最近 20 个项目，防 context 膨胀
            for p in projects.iter().take(20) {
                prompt.push_str(&format!("- {} ({}): {}\n", p.name, p.status, p.description));
            }
        }
    }

    prompt
}