package com.xly.web;

import com.xly.agent.AgentIdentity;
import com.xly.service.AuthzService;
import com.xly.service.ConversationService;
import org.springframework.http.HttpStatus;
import org.springframework.web.bind.annotation.DeleteMapping;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.server.ResponseStatusException;

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

/**
 * 会话管理 REST —— 支撑前端的「多命名会话」侧栏（列表 / 新建 / 删除 / 历史）。
 *
 * <p><b>身份</b>：一律由 {@code Authorization} 头经 {@link AuthzService#resolveIdentity} 服务端内省得出，
 * 不接受客户端自报的 userid；会话 id 绑定用户命名空间，越权访问他人会话直接 403。
 */
@RestController
@RequestMapping("/api/agent/conversations")
public class ConversationController {

    private final ConversationService conversations;
    private final AuthzService authz;

    public ConversationController(ConversationService conversations, AuthzService authz) {
        this.conversations = conversations;
        this.authz = authz;
    }

    /** 列出当前登录用户的会话（最近更新在前）。 */
    @GetMapping
    public List<Map<String, Object>> list(@RequestHeader(value = "Authorization", required = false) String auth) {
        return conversations.list(identity(auth).userId());
    }

    /** 新建空会话，返回 conversationId。 */
    @PostMapping
    public Map<String, String> create(@RequestHeader(value = "Authorization", required = false) String auth) {
        return Map.of("conversationId", conversations.create(identity(auth).userId()));
    }

    /** 删除自己的会话（含消息记忆、账本、状态槽）。 */
    @DeleteMapping("/{convId}")
    public Map<String, Object> delete(@PathVariable("convId") String convId,
                                      @RequestHeader(value = "Authorization", required = false) String auth) {
        String uid = requireOwner(auth, convId);
        conversations.delete(uid, convId);
        return Map.of("ok", true);
    }

    /** 自己会话的历史消息（用于切换会话时回填）。 */
    @GetMapping("/{convId}/messages")
    public List<Map<String, String>> messages(@PathVariable("convId") String convId,
                                              @RequestHeader(value = "Authorization", required = false) String auth) {
        requireOwner(auth, convId);
        return conversations.history(convId);
    }

    private AgentIdentity identity(String auth) {
        AgentIdentity id = authz.resolveIdentity(auth);
        if (id == null) {
            throw new ResponseStatusException(HttpStatus.UNAUTHORIZED, "登录已过期或未登录");
        }
        return id;
    }

    private String requireOwner(String auth, String convId) {
        AgentIdentity id = identity(auth);
        if (!conversations.owns(id.userId(), convId)) {
            throw new ResponseStatusException(HttpStatus.FORBIDDEN, "无权访问该会话");
        }
        return id.userId();
    }
}