import { useEffect, useState } from "react";

import { ApiRequestError, type Employee, type Role } from "../../services/api";
import { useApi, useAuth } from "../../context/AuthContext";
import Icon from "../../components/common/Icon";
import {
  formFieldClass,
  formInputClass,
  iconButtonClass,
  modalBackdropClass,
  modalCompactClass,
  modalEyebrowClass,
  modalFooterClass,
  modalFormClass,
  modalHeaderClass,
  modalTitleClass,
  primaryButtonClass,
  secondaryButtonClass,
} from "../platform/modalUi";

import "../../styles/admin.css";

const EMPTY_FORM = {
  username: "",
  display_name: "",
  email: "",
  role_code: "developer" as "admin" | "developer",
  password: "",
  status: "active" as "active" | "disabled" | "locked",
};

export function UserManagementPage({
  onNotify,
  onConnectionChange,
}: {
  onNotify: (notice: { tone: "success" | "error" | "info"; message: string }) => void;
  onConnectionChange: (online: boolean) => void;
}) {
  const api = useApi();
  const { user } = useAuth();
  const [employees, setEmployees] = useState<Employee[]>([]);
  const [roles, setRoles] = useState<Role[]>([]);
  const [loading, setLoading] = useState(true);
  const [saving, setSaving] = useState(false);
  const [editing, setEditing] = useState<Employee | null>(null);
  const [dialogOpen, setDialogOpen] = useState(false);
  const [form, setForm] = useState(EMPTY_FORM);
  const [userSearchTerm, setUserSearchTerm] = useState("");

  const canManage = user?.role_code === "admin";

  const load = async (): Promise<void> => {
    setLoading(true);
    try {
      const [employeeList, roleList] = await Promise.all([
        api.listPlatformEmployees(),
        api.listPlatformRoles(),
      ]);
      setEmployees(employeeList);
      setRoles(roleList);
      onConnectionChange(true);
    } catch (error) {
      onConnectionChange(false);
      onNotify({
        tone: "error",
        message: error instanceof Error ? error.message : "用户列表加载失败",
      });
    } finally {
      setLoading(false);
    }
  };

  useEffect(() => {
    void load();
  }, []);

  const openCreate = (): void => {
    setEditing(null);
    setForm(EMPTY_FORM);
    setDialogOpen(true);
  };

  const openEdit = (employee: Employee): void => {
    setEditing(employee);
    setForm({
      username: employee.username,
      display_name: employee.display_name,
      email: employee.email ?? "",
      role_code: employee.role_code,
      password: "",
      status: employee.status,
    });
    setDialogOpen(true);
  };

  const submit = async (event: React.FormEvent): Promise<void> => {
    event.preventDefault();
    if (!form.display_name.trim() || (!editing && !form.username.trim())) return;
    // 新建用户时密码必填
    if (!editing && !form.password.trim()) {
      onNotify({ tone: "error", message: "请输入密码" });
      return;
    }
    // 编辑自身时,前端二次拦截禁用 status / role_code 的修改;管理员账号禁止停用/锁定
    if (editing) {
      const editingSelf = editing.user_id === user?.user_id;
      const targetIsAdmin = editing.role_code === "admin";
      if (editingSelf && form.status !== editing.status) {
        onNotify({ tone: "error", message: "不能停用当前登录账号" });
        return;
      }
      if (targetIsAdmin && form.status !== editing.status) {
        onNotify({ tone: "error", message: "不能停用或锁定管理员账号" });
        return;
      }
      if (editingSelf && form.role_code !== editing.role_code) {
        onNotify({ tone: "error", message: "不能降级自身管理员角色" });
        return;
      }
    }
    // 密码长度校验 8~72 字符
    if (form.password && (form.password.length < 8 || form.password.length > 72)) {
      onNotify({ tone: "error", message: "密码长度必须在 8~72 字符之间" });
      return;
    }
    setSaving(true);
    try {
      if (editing) {
        const updated = await api.updatePlatformEmployee(editing.user_id, {
          display_name: form.display_name.trim(),
          email: form.email.trim() || null,
          role_code: form.role_code,
          status: form.status,
        });
        setEmployees((current) => current.map(
          (item) => item.user_id === updated.user_id ? updated : item,
        ));
        onNotify({ tone: "success", message: "用户信息已更新" });
      } else {
        const created = await api.createPlatformEmployee({
          username: form.username.trim(),
          display_name: form.display_name.trim(),
          email: form.email.trim() || undefined,
          password: form.password,
          role_code: "developer",
        });
        setEmployees((current) => [...current, created]);
        onNotify({ tone: "success", message: "用户已添加" });
      }
      setDialogOpen(false);
    } catch (error) {
      onNotify({
        tone: "error",
        message: error instanceof ApiRequestError ? error.message : "保存用户失败",
      });
    } finally {
      setSaving(false);
    }
  };

  const remove = async (employee: Employee): Promise<void> => {
    if (!window.confirm(`确定从平台删除用户"${employee.display_name}"吗？`)) return;
    try {
      await api.deletePlatformEmployee(employee.user_id);
      setEmployees((current) => current.filter((item) => item.user_id !== employee.user_id));
      onNotify({ tone: "success", message: "用户已删除" });
    } catch (error) {
      onNotify({
        tone: "error",
        message: error instanceof Error ? error.message : "删除用户失败",
      });
    }
  };

  return (
    <section className="admin-page">
      <div className="admin-toolbar">
        <div className="admin-toolbar__search">
          <Icon name="search" size={14} />
          <input
            type="text"
            placeholder="请输入用户名"
            className="admin-toolbar__input"
            value={userSearchTerm}
            onChange={(event) => setUserSearchTerm(event.target.value)}
          />
        </div>
        <button
          className="primary-button admin-toolbar__button"
          type="button"
          disabled={!canManage}
          onClick={openCreate}
        >
          <Icon name="plus" size={15} />
          新建用户
        </button>
      </div>

      {!canManage && <div className="admin-readonly">当前为开发人员，只能查看用户列表。</div>}
      <div className="employee-table">
        <div className="employee-table__head"><span>用户</span><span>账号</span><span>角色</span><span>状态</span><span>操作</span></div>
        {loading ? (
          <p className="admin-empty">正在加载用户…</p>
        ) : (
          employees
            .filter((employee) => {
              const term = userSearchTerm.toLowerCase().trim();
              if (!term) return true;
              return (
                employee.display_name.toLowerCase().includes(term) ||
                employee.username.toLowerCase().includes(term) ||
                (employee.email && employee.email.toLowerCase().includes(term))
              );
            })
            .map((employee) => {
              const isProtectedAdmin = employee.role_code === "admin";
              return (
                <div className="employee-row" key={employee.user_id}>
                  <span className="employee-name"><b className="avatar">{employee.display_name.slice(0, 1)}</b><span><strong>{employee.display_name}</strong><small>{employee.email ?? "未设置邮箱"}</small></span></span>
                  <code>{employee.username}</code>
                  {employee.role_code ? (<span className={`role-pill is-${employee.role_code}`}>{employee.role_name}</span>) : (<span>-</span>)}
                  <span className={`status-pill is-${employee.status}`}>{employee.status === "active" ? "正常" : employee.status === "disabled" ? "已停用" : "已锁定"}</span>
                  <span className="employee-actions">
                    <button type="button" disabled={!canManage} onClick={() => openEdit(employee)}>编辑</button>
                    <button type="button" className="is-danger" disabled={!canManage || isProtectedAdmin} title={isProtectedAdmin ? "管理员账号不能删除" : "删除"} onClick={() => void remove(employee)}>删除</button>
                  </span>
                </div>
              );
            })
        )}
      </div>

      {dialogOpen && (
        <div className={modalBackdropClass} role="presentation">
          <section className={modalCompactClass} role="dialog" aria-modal="true">
            <div className={modalHeaderClass}>
              <div>
                <span className={modalEyebrowClass}>EMPLOYEE</span>
                <h2 className={modalTitleClass}>{editing ? "编辑用户" : "添加用户"}</h2>
              </div>
              <button className={iconButtonClass} type="button" aria-label="关闭" onClick={() => setDialogOpen(false)}>
                <Icon name="close" />
              </button>
            </div>
            <form className={modalFormClass} onSubmit={(event) => void submit(event)}>
              <label className={formFieldClass}>
                <span>姓名<span className="text-[#e74c3c]">*</span></span>
                <input
                  className={formInputClass}
                  autoFocus={!editing}
                  value={form.display_name}
                  onChange={(event) => setForm({ ...form, display_name: event.target.value })}
                  placeholder="请输入姓名"
                />
              </label>
              <label className={formFieldClass}>
                <span>登录账号<span className="text-[#e74c3c]">*</span></span>
                <input
                  className={formInputClass}
                  disabled={Boolean(editing)}
                  value={form.username}
                  onChange={(event) => setForm({ ...form, username: event.target.value })}
                  placeholder="请输入登录账号"
                  autoComplete="username"
                />
              </label>
              {!editing && (
                <label className={formFieldClass}>
                  <span>密码<span className="text-[#e74c3c]">*</span></span>
                  <input
                    className={formInputClass}
                    type="password"
                    autoComplete="new-password"
                    value={form.password}
                    onChange={(event) => setForm({ ...form, password: event.target.value })}
                    placeholder="请输入密码（8~72 字符）"
                  />
                </label>
              )}
              <label className={formFieldClass}>
                <span>邮箱</span>
                <input
                  className={formInputClass}
                  type="email"
                  autoComplete="email"
                  value={form.email}
                  onChange={(event) => setForm({ ...form, email: event.target.value })}
                  placeholder="请输入邮箱（可选）"
                />
              </label>
              {editing && (
                <label className={formFieldClass}>
                  <span>角色</span>
                  <select
                    className={formInputClass}
                    value={form.role_code}
                    disabled={editing.user_id === user?.user_id || roles.length === 0}
                    onChange={(event) => setForm({ ...form, role_code: event.target.value as typeof form.role_code })}
                  >
                    {roles.length === 0 ? (
                      <option value="" disabled>加载中…</option>
                    ) : (
                      roles.map((role) => (
                        <option key={role.role_code} value={role.role_code}>
                          {role.role_name}
                        </option>
                      ))
                    )}
                  </select>
                </label>
              )}
              {editing && (
                <label className={formFieldClass}>
                  <span>状态</span>
                  <select
                    className={formInputClass}
                    value={form.status}
                    disabled={Boolean(editing) && (editing.user_id === user?.user_id || editing.role_code === "admin")}
                    onChange={(event) => setForm({ ...form, status: event.target.value as typeof form.status })}
                  >
                    <option value="active">正常</option>
                    <option value="disabled">停用</option>
                    <option value="locked">锁定</option>
                  </select>
                </label>
              )}
              <div className={modalFooterClass}>
                <button className={secondaryButtonClass} type="button" onClick={() => setDialogOpen(false)}>取消</button>
                <button className={primaryButtonClass} type="submit" disabled={saving}>{saving ? "保存中…" : "保存"}</button>
              </div>
            </form>
          </section>
        </div>
      )}
    </section>
  );
}