package com.vincent.rsf.server.ai.controller;

import com.fasterxml.jackson.databind.JsonNode;
import com.vincent.rsf.framework.common.R;
import com.vincent.rsf.server.ai.config.AiProperties;
import com.vincent.rsf.server.ai.dto.AiChatStreamRequest;
import com.vincent.rsf.server.ai.dto.AiSessionCreateRequest;
import com.vincent.rsf.server.ai.dto.AiSessionRenameRequest;
import com.vincent.rsf.server.ai.dto.GatewayChatMessage;
import com.vincent.rsf.server.ai.dto.GatewayChatRequest;
import com.vincent.rsf.server.ai.model.AiChatMessage;
import com.vincent.rsf.server.ai.model.AiChatSession;
import com.vincent.rsf.server.ai.model.AiPromptContext;
import com.vincent.rsf.server.ai.service.AiGatewayClient;
import com.vincent.rsf.server.ai.service.AiPromptContextService;
import com.vincent.rsf.server.ai.service.AiRuntimeConfigService;
import com.vincent.rsf.server.ai.service.AiSessionService;
import com.vincent.rsf.server.system.controller.BaseController;
import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.mvc.method.annotation.SseEmitter;

import javax.annotation.Resource;
import java.io.IOException;
import java.util.Date;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

@RestController
@RequestMapping("/ai")
public class AiController extends BaseController {

    @Resource
    private AiSessionService aiSessionService;
    @Resource
    private AiProperties aiProperties;
    @Resource
    private AiGatewayClient aiGatewayClient;
    @Resource
    private AiRuntimeConfigService aiRuntimeConfigService;
    @Resource
    private AiPromptContextService aiPromptContextService;

    @GetMapping("/model/list")
    public R modelList() {
        List<Map<String, Object>> models = new java.util.ArrayList<>();
        for (AiRuntimeConfigService.ModelRuntimeConfig model : aiRuntimeConfigService.listEnabledModels()) {
            Map<String, Object> item = new LinkedHashMap<>();
            item.put("code", model.getCode());
            item.put("name", model.getName());
            item.put("provider", model.getProvider());
            item.put("enabled", model.getEnabled());
            models.add(item);
        }
        return R.ok().add(models);
    }

    @GetMapping("/session/list")
    public R sessionList() {
        return R.ok().add(aiSessionService.listSessions(getTenantId(), getLoginUserId()));
    }

    @PostMapping("/session/create")
    public R createSession(@RequestBody(required = false) AiSessionCreateRequest request) {
        AiChatSession session = aiSessionService.createSession(
                getTenantId(),
                getLoginUserId(),
                request == null ? null : request.getTitle(),
                request == null ? null : request.getModelCode()
        );
        return R.ok().add(session);
    }

    @PostMapping("/session/{sessionId}/rename")
    public R renameSession(@PathVariable("sessionId") String sessionId, @RequestBody AiSessionRenameRequest request) {
        AiChatSession session = aiSessionService.renameSession(getTenantId(), getLoginUserId(), sessionId, request.getTitle());
        return R.ok().add(session);
    }

    @PostMapping("/session/remove/{sessionId}")
    public R removeSession(@PathVariable("sessionId") String sessionId) {
        aiSessionService.removeSession(getTenantId(), getLoginUserId(), sessionId);
        return R.ok();
    }

    @GetMapping("/session/{sessionId}/messages")
    public R messageList(@PathVariable("sessionId") String sessionId) {
        return R.ok().add(aiSessionService.listMessages(getTenantId(), getLoginUserId(), sessionId));
    }

    @PostMapping("/chat/stop")
    public R stop(@RequestBody AiChatStreamRequest request) {
        if (request != null && request.getSessionId() != null) {
            aiSessionService.requestStop(request.getSessionId());
        }
        return R.ok();
    }

    @PostMapping(value = "/chat/stream", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
    public SseEmitter chatStream(@RequestBody AiChatStreamRequest request) {
        SseEmitter emitter = new SseEmitter(0L);
        Long tenantId = getTenantId();
        Long userId = getLoginUserId();
        if (tenantId == null || userId == null) {
            completeWithError(emitter, "请先登录后再使用AI助手");
            return emitter;
        }
        if (request == null || request.getMessage() == null || request.getMessage().trim().isEmpty()) {
            completeWithError(emitter, "消息内容不能为空");
            return emitter;
        }
        AiChatSession session = aiSessionService.ensureSession(tenantId, userId, request.getSessionId(), request.getModelCode());
        aiSessionService.clearStopFlag(session.getId());
        aiSessionService.appendMessage(tenantId, userId, session.getId(), "user", request.getMessage(), session.getModelCode());
        AiRuntimeConfigService.ModelRuntimeConfig modelRuntimeConfig = aiRuntimeConfigService.resolveModel(session.getModelCode());
        List<AiChatMessage> contextMessages = aiSessionService.listContextMessages(
                tenantId,
                userId,
                session.getId(),
                modelRuntimeConfig.getMaxContextMessages()
        );

        Thread thread = new Thread(() -> {
            StringBuilder assistantReply = new StringBuilder();
            boolean doneSent = false;
            try {
                emitter.send(SseEmitter.event().name("session").data(buildSessionPayload(session), MediaType.APPLICATION_JSON));
                GatewayChatRequest gatewayChatRequest = buildGatewayRequest(
                        tenantId,
                        userId,
                        session,
                        contextMessages,
                        modelRuntimeConfig,
                        request.getMessage()
                );
                aiGatewayClient.stream(gatewayChatRequest, event -> handleGatewayEvent(
                        emitter,
                        event,
                        session,
                        assistantReply
                ));
                if (aiSessionService.isStopRequested(session.getId())) {
                    if (assistantReply.length() > 0) {
                        aiSessionService.appendMessage(tenantId, userId, session.getId(), "assistant", assistantReply.toString(), session.getModelCode());
                    }
                    emitter.send(SseEmitter.event().name("done").data(buildDonePayload(session, true), MediaType.APPLICATION_JSON));
                    doneSent = true;
                }
            } catch (Exception e) {
                try {
                    emitter.send(SseEmitter.event().name("error").data(buildErrorPayload(e.getMessage()), MediaType.APPLICATION_JSON));
                } catch (IOException ignore) {
                }
            } finally {
                if (!doneSent && assistantReply.length() > 0) {
                    aiSessionService.appendMessage(tenantId, userId, session.getId(), "assistant", assistantReply.toString(), session.getModelCode());
                    try {
                        emitter.send(SseEmitter.event().name("done").data(buildDonePayload(session, false), MediaType.APPLICATION_JSON));
                    } catch (IOException ignore) {
                    }
                }
                emitter.complete();
                aiSessionService.clearStopFlag(session.getId());
            }
        }, "ai-chat-stream-" + session.getId());
        thread.setDaemon(true);
        thread.start();
        return emitter;
    }

    private boolean handleGatewayEvent(SseEmitter emitter, JsonNode event, AiChatSession session,
                                       StringBuilder assistantReply) throws Exception {
        if (aiSessionService.isStopRequested(session.getId())) {
            return false;
        }
        String type = event.path("type").asText();
        if ("delta".equals(type)) {
            String content = event.path("content").asText("");
            assistantReply.append(content);
            emitter.send(SseEmitter.event().name("delta").data(buildDeltaPayload(session, content), MediaType.APPLICATION_JSON));
            return true;
        }
        if ("error".equals(type)) {
            emitter.send(SseEmitter.event().name("error").data(buildErrorPayload(event.path("message").asText("模型调用失败")), MediaType.APPLICATION_JSON));
            return false;
        }
        if ("done".equals(type)) {
            return false;
        }
        return true;
    }

    private GatewayChatRequest buildGatewayRequest(Long tenantId, Long userId, AiChatSession session, List<AiChatMessage> contextMessages,
                                                   AiRuntimeConfigService.ModelRuntimeConfig modelRuntimeConfig,
                                                   String latestQuestion) {
        GatewayChatRequest request = new GatewayChatRequest();
        request.setSessionId(session.getId());
        request.setModelCode(session.getModelCode());
        request.setSystemPrompt(aiPromptContextService.buildSystemPrompt(
                modelRuntimeConfig.getSystemPrompt(),
                new AiPromptContext()
                        .setTenantId(tenantId)
                        .setUserId(userId)
                        .setSessionId(session.getId())
                        .setModelCode(session.getModelCode())
                        .setQuestion(latestQuestion)
        ));
        request.setChatUrl(modelRuntimeConfig.getChatUrl());
        request.setApiKey(modelRuntimeConfig.getApiKey());
        request.setModelName(modelRuntimeConfig.getModelName());
        for (AiChatMessage contextMessage : contextMessages) {
            GatewayChatMessage item = new GatewayChatMessage();
            item.setRole(contextMessage.getRole());
            item.setContent(contextMessage.getContent());
            request.getMessages().add(item);
        }
        return request;
    }

    private Map<String, Object> buildSessionPayload(AiChatSession session) {
        Map<String, Object> payload = new LinkedHashMap<>();
        payload.put("sessionId", session.getId());
        payload.put("title", session.getTitle());
        payload.put("modelCode", session.getModelCode());
        return payload;
    }

    private Map<String, Object> buildDeltaPayload(AiChatSession session, String content) {
        Map<String, Object> payload = new LinkedHashMap<>();
        payload.put("sessionId", session.getId());
        payload.put("modelCode", session.getModelCode());
        payload.put("content", content);
        payload.put("timestamp", new Date().getTime());
        return payload;
    }

    private Map<String, Object> buildDonePayload(AiChatSession session, boolean stopped) {
        Map<String, Object> payload = new LinkedHashMap<>();
        payload.put("sessionId", session.getId());
        payload.put("modelCode", session.getModelCode());
        payload.put("stopped", stopped);
        return payload;
    }

    private Map<String, Object> buildErrorPayload(String message) {
        Map<String, Object> payload = new LinkedHashMap<>();
        payload.put("message", message == null ? "AI服务异常" : message);
        return payload;
    }

    private void completeWithError(SseEmitter emitter, String message) {
        try {
            emitter.send(SseEmitter.event().name("error").data(buildErrorPayload(message), MediaType.APPLICATION_JSON));
        } catch (IOException ignore) {
        }
        emitter.complete();
    }

}