package com.learn.controller;

import com.learn.dto.ApiResponse;
import com.learn.dto.ChatRequest;
import com.learn.dto.RAGQueryRequest;
import com.learn.service.AgentService;
import com.learn.service.ChatService;
import com.learn.service.PromptTemplateService;
import com.learn.service.RAGService;
import jakarta.validation.Valid;
import org.springframework.ai.document.Document;
import org.springframework.http.MediaType;
import org.springframework.http.codec.ServerSentEvent;
import org.springframework.web.bind.annotation.*;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.util.List;
import java.util.Map;

@RestController
public class ChatController {

    private final ChatService chatService;
    private final AgentService agentService;
    private final RAGService ragService;
    private final PromptTemplateService promptService;

    public ChatController(ChatService chatService, AgentService agentService,
                          RAGService ragService, PromptTemplateService promptService) {
        this.chatService = chatService;
        this.agentService = agentService;
        this.ragService = ragService;
        this.promptService = promptService;
    }

    // ==================== Week 9 复用: 基础对话 ====================

    @PostMapping("/api/chat")
    public ApiResponse<Map<String, String>> chat(@Valid @RequestBody ChatRequest request) {
        String convId = request.getConversationId() != null ? request.getConversationId() : "default";
        String reply = chatService.chat(request.getMessage(), convId);
        return ApiResponse.success(Map.of("reply", reply, "conversationId", convId));
    }

    @PostMapping(value = "/api/chat/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
    public Flux<ServerSentEvent<String>> chatStream(@Valid @RequestBody ChatRequest request) {
        return chatService.chatStream(request.getMessage(), request.getConversationId())
                .map(token -> ServerSentEvent.<String>builder().data(token).build())
                .concatWith(Mono.just(ServerSentEvent.<String>builder()
                        .event("done").data("[DONE]").build()));
    }

    @GetMapping("/api/chat/history")
    public ApiResponse<?> getHistory(@RequestParam(defaultValue = "default") String conversationId) {
        return ApiResponse.success(chatService.getHistory(conversationId));
    }

    @DeleteMapping("/api/chat/history")
    public ApiResponse<?> clearHistory(@RequestParam(defaultValue = "default") String conversationId) {
        chatService.clearHistory(conversationId);
        return ApiResponse.success("已清除会话: " + conversationId);
    }

    // ==================== Day 3-4: Agent 任务（Function Calling） ====================

    /**
     * 同步 Agent 执行 —— 模型自动选择并调用工具。
     *
     * POST /api/agent
     * Body: {"message": "北京天气如何？", "conversationId": "会话ID（可选）"}
     */
    @PostMapping("/api/agent")
    public ApiResponse<Map<String, Object>> agent(@Valid @RequestBody ChatRequest request) {
        var result = agentService.execute(request.getMessage(), request.getConversationId());
        return ApiResponse.success(result);
    }

    /**
     * 流式 Agent 执行。
     *
     * POST /api/agent/stream
     */
    @PostMapping(value = "/api/agent/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
    public Flux<ServerSentEvent<String>> agentStream(@Valid @RequestBody ChatRequest request) {
        return agentService.executeStream(request.getMessage(), request.getConversationId())
                .map(token -> ServerSentEvent.<String>builder().data(token).build())
                .concatWith(Mono.just(ServerSentEvent.<String>builder()
                        .event("done").data("[DONE]").build()));
    }

    // ==================== Day 6: RAG 检索增强 ====================

    /**
     * RAG 检索（只检索不生成，看检索效果）。
     *
     * POST /api/rag/search
     * Body: {"question": "什么是 Spring AI？", "topK": 3}
     */
    @PostMapping("/api/rag/search")
    public ApiResponse<List<Map<String, Object>>> ragSearch(@Valid @RequestBody RAGQueryRequest request) {
        return ApiResponse.success(ragService.search(request.getQuestion(), request.getTopK()));
    }

    /**
     * 向知识库添加文档。
     *
     * POST /api/rag/load
     * Body: [{"text": "文档内容", "metadata": {"source": "spring-doc"}}]
     */
    @PostMapping("/api/rag/load")
    public ApiResponse<Map<String, Object>> ragLoad(@RequestBody List<Map<String, Object>> documents) {
        var docs = documents.stream()
                .map(m -> {
                    String text = (String) m.get("text");
                    @SuppressWarnings("unchecked")
                    var metadata = (Map<String, Object>) m.getOrDefault("metadata", Map.of());
                    return new Document(text, new java.util.HashMap<>(metadata));
                })
                .toList();
        int count = ragService.addDocuments(docs);
        return ApiResponse.created(Map.of("added", count));
    }

    // ==================== Day 7: Prompt 模板管理 ====================

    /**
     * 获取所有模板名称和预览。
     *
     * GET /api/prompts
     */
    @GetMapping("/api/prompts")
    public ApiResponse<List<Map<String, String>>> listPrompts() {
        return ApiResponse.success(promptService.list());
    }

    /**
     * 获取指定模板的原始内容。
     *
     * GET /api/prompts/{name}
     */
    @GetMapping("/api/prompts/{name}")
    public ApiResponse<Map<String, String>> getPrompt(@PathVariable String name) {
        String content = promptService.getTemplate(name);
        return ApiResponse.success(Map.of("name", name, "content", content));
    }

    /**
     * 使用 Prompt 模板进行对话。
     *
     * POST /api/chat/with-template
     * Body: {"message": "用户消息", "templateName": "java-expert", "params": {"key": "value"}, "conversationId": "xxx"}
     */
    @PostMapping("/api/chat/with-template")
    public ApiResponse<Map<String, String>> chatWithTemplate(@RequestBody Map<String, Object> body) {
        String message = (String) body.get("message");
        String templateName = (String) body.get("templateName");
        String conversationId = (String) body.getOrDefault("conversationId", "default");
        @SuppressWarnings("unchecked")
        var params = (Map<String, String>) body.getOrDefault("params", Map.of());

        String templateContent = promptService.apply(templateName, params);
        String reply = chatService.chatWithTemplate(templateContent, message, conversationId);
        return ApiResponse.success(Map.of("reply", reply, "conversationId", conversationId));
    }
}