/*
 * @file ai_common.hpp
 * @brief Shared types and utilities for AI provider plugins (OpenAI / Anthropic).
 * AI 提供者插件（OpenAI / Anthropic）的共享类型和工具函数。
 * Copyright (c) 2026 dstalk contributors. GPLv3.
 */

#pragma once

#include "dstalk/dstalk_host.h"
#include "dstalk/dstalk_services.h"

#include <boost/json.hpp>
#include <string>
#include <vector>

namespace dstalk_ai {

namespace json = boost::json;

// ============================================================================
// 共享类型 / Shared types
// ============================================================================

/// Provider connection configuration / 服务商连接配置
struct PluginConfig {
    std::string provider;
    std::string base_url;
    std::string api_key;
    std::string model;
    int max_tokens = 4096;
    double temperature = 0.7;
};

/// Per-index tool-call accumulator for SSE streaming / SSE 流式传输的按索引工具调用累积器
struct ToolCallAccum {
    int index = -1;
    std::string id;
    std::string name;
    std::string arguments;  // 增量拼接的 JSON arguments / incrementally concatenated JSON arguments
};

/// Streaming context passed through SSE callbacks / 通过 SSE 回调传递的流式上下文
struct StreamContext {
    const dstalk_host_api_t* host = nullptr;
    dstalk_stream_cb user_cb = nullptr;
    void* userdata = nullptr;
    std::string accumulated;
    std::vector<ToolCallAccum> tool_calls;
    int sse_parse_errors = 0;        // 连续 SSE 解析错误计数器 / consecutive SSE parse error counter
    bool streaming_ok = true;        // OpenAI: tracks stream health
    bool saw_data_line = false;      // Anthropic: tracks if any SSE data received
};

/// Maximum consecutive SSE parse errors before aborting the stream / 中止流之前的最大连续 SSE 解析错误数
inline constexpr int kMaxSseParseErrors = 5;

// ============================================================================
// 函数声明（实现于 ai_common.cpp） / Function declarations (implemented in ai_common.cpp)
// ============================================================================

/// Securely zero memory through volatile write to prevent compiler optimization.
/// 通过 volatile 写入零来安全擦除内存，防止编译器优化。
void secure_zero(void* p, size_t n);

/// Parse a URL into scheme, host, port, and target path components.
/// 将 URL 解析为 scheme、host、port 和 target path 组件。
bool extract_host_port(const std::string& url,
    std::string& scheme_out, std::string& host_out,
    std::string& port_out, std::string& target_out);

// ============================================================================
// 内联工具函数 / Inline utility functions
// ============================================================================

/// Free all host-allocated string fields in a chat result struct.
/// 释放 chat result 结构体中所有主机分配的字符串字段。
inline void free_chat_result(const dstalk_host_api_t* host, dstalk_chat_result_t* result) {
    if (!result || !host) return;
    if (result->content)         { host->free((void*)result->content);         result->content = nullptr; }
    if (result->error)           { host->free((void*)result->error);           result->error = nullptr; }
    if (result->tool_calls_json) { host->free((void*)result->tool_calls_json); result->tool_calls_json = nullptr; }
}

/// Cache tools_json from the tools service for reuse in chat/chat_stream.
/// 从 tools service 缓存 tools_json，供 chat/chat_stream 复用。
inline void cache_tools_json(const dstalk_host_api_t* host, std::string& tools_json) {
    if (!host) return;
    auto* tools_svc = reinterpret_cast<const dstalk_tools_service_t*>(
        host->query_service("tools", 1));
    if (tools_svc && tools_svc->get_tools_json) {
        char* j = tools_svc->get_tools_json();
        if (j) {
            tools_json = j;
            host->free(j);
        }
    }
}

/// Serialize accumulated tool_calls into OpenAI-compatible JSON array.
/// 将累积的 tool_calls 序列化为兼容 OpenAI 格式的 JSON 数组。
inline std::string serialize_tool_calls(const std::vector<ToolCallAccum>& tool_calls) {
    json::array tc_array;
    for (const auto& tc : tool_calls) {
        json::object tc_obj;
        tc_obj["index"] = tc.index;
        if (!tc.id.empty())   tc_obj["id"]   = tc.id;
        tc_obj["type"] = "function";
        json::object func;
        if (!tc.name.empty()) func["name"] = tc.name;
        func["arguments"] = tc.arguments;
        tc_obj["function"] = func;
        tc_array.push_back(std::move(tc_obj));
    }
    return json::serialize(tc_array);
}

} // namespace dstalk_ai