import { useEffect, useState } from "react";
import { Link } from "react-router-dom";
import { useQuery } from "@tanstack/react-query";
import { mapApiErrorMessage } from "../api/errorMessages";
import { fetchPortalHome, type PortalHomePayload } from "../api/portal";
import { isApiError } from "../api/types";
import { useAuth } from "../auth/AuthContext";
import { hasAnyPermission, isManagerRole } from "../auth/permissions";
import { ErrorBoundary } from "../components/common/ErrorBoundary";
import { WelcomeDialog } from "../components/onboarding/WelcomeDialog";
import { PageScaffold } from "../components/patterns/PageScaffold";
import { SectionPanel } from "../components/patterns/SectionPanel";
import { Button } from "../components/ui/button";
import {
  clearWelcomeDialogFlag,
  shouldShowWelcomeDialog,
} from "../lib/onboardingGuide";

type RoleCapabilities = NonNullable<PortalHomePayload["roleCapabilities"]>;

type WorkItem = {
  key: string;
  title: string;
  reason: string;
  meta: string;
  href: string;
  actionLabel: string;
  severity: "normal" | "warning" | "high";
  icon: string;
  priority: number;
  count: number;
};

type EmptyAction = {
  key: string;
  label: string;
  href: string;
  variant?: "primary" | "secondary" | "ghost";
};

type QuickEntry = {
  key: string;
  label: string;
  href: string;
  actionLabel: string;
  icon: string;
};

const LEAVE_PORTAL_PERMISSIONS = ["leave.view_own", "leave.view_all", "leave.create", "leave.submit"];
const EXPENSE_PORTAL_PERMISSIONS = ["expense.view_own", "expense.view_all", "expense.create", "expense.proxy_manage"];
const PROCUREMENT_PORTAL_PERMISSIONS = ["procurement.view_own", "procurement.view_all", "procurement.create", "procurement.submit"];
const TRAVEL_PORTAL_PERMISSIONS = ["travel.view_own", "travel.view_all", "travel.create", "travel.submit"];
const APPROVAL_PORTAL_PERMISSIONS = ["expense.approve", "leave.approve", "procurement.approve", "travel.approve"];
const FINANCE_PORTAL_PERMISSIONS = ["payment.batch.manage", "risk.review.manage", "expense.finance.pay"];
const SYSTEM_PORTAL_PERMISSIONS = ["system.users", "system.settings", "system.audit.view", "notification.channel.manage", "payment.account.read", "payment.account.manage"];
const CONTRACT_PORTAL_PERMISSIONS = ["project.view_all", "project.manage", "system.settings"];
const PROJECT_PORTAL_PERMISSIONS = ["project.view_own", "project.view_all", "project.manage"];
const ASSET_PORTAL_PERMISSIONS = ["asset.view_own", "asset.view_all", "asset.manage", "asset.transfer", "asset.inventory"];
const INVOICE_PORTAL_PERMISSIONS = ["invoice.manage"];

const SEVERITY_RANK = {
  high: 3,
  warning: 2,
  normal: 1,
} as const;

function buildFallbackRoleCapabilities(permissions: string[], roleCodes: string[]): RoleCapabilities {
  const hasAdminRole = roleCodes.includes("admin") || hasAnyPermission(permissions, ["*"]);
  const hasBusinessApproverRole = roleCodes.some((roleCode) =>
    ["manager", "ceo", "finance", "finance_mgr", "hr"].includes(roleCode),
  );
  const hasFinanceRole = roleCodes.some((roleCode) => ["finance", "finance_mgr"].includes(roleCode));

  return {
    canSubmitApplications: hasAnyPermission(permissions, [
      ...LEAVE_PORTAL_PERMISSIONS,
      ...EXPENSE_PORTAL_PERMISSIONS,
      ...PROCUREMENT_PORTAL_PERMISSIONS,
      ...TRAVEL_PORTAL_PERMISSIONS,
    ]),
    canApproveTasks: hasBusinessApproverRole && hasAnyPermission(permissions, APPROVAL_PORTAL_PERMISSIONS),
    canUseFinance: hasFinanceRole && hasAnyPermission(permissions, FINANCE_PORTAL_PERMISSIONS),
    canManageSystem: hasAdminRole || hasAnyPermission(permissions, SYSTEM_PORTAL_PERMISSIONS),
    canViewTeam: hasBusinessApproverRole || hasAnyPermission(permissions, ["report.dashboard.view", "system.users", "project.manage"]),
    isAdminOnly: hasAdminRole && !hasBusinessApproverRole,
  };
}

function sortWorkItems(items: WorkItem[]) {
  return [...items].sort((left, right) => {
    const severityCompare = SEVERITY_RANK[right.severity] - SEVERITY_RANK[left.severity];
    if (severityCompare !== 0) {
      return severityCompare;
    }
    return right.priority - left.priority;
  });
}

function uniqueWorkItems(items: WorkItem[]) {
  const deduped = new Map<string, WorkItem>();
  for (const item of items) {
    if (!deduped.has(item.key)) {
      deduped.set(item.key, item);
    }
  }
  return sortWorkItems(Array.from(deduped.values()));
}

function buildTodayActionItems(payload: PortalHomePayload, roleCapabilities: RoleCapabilities) {
  const items: WorkItem[] = [];

  if (payload.pendingTasks.count > 0) {
    items.push({
      key: "workflow-pending",
      title: `待我处理 ${payload.pendingTasks.count} 条`,
      reason: "审批、确认或流程处理正在等你。",
      meta: "流程待办",
      href: payload.pendingTasks.href,
      actionLabel: "去处理",
      severity: "warning",
      icon: "fact_check",
      priority: 100,
      count: payload.pendingTasks.count,
    });
  }

  const openTodoCount = payload.todoSummary?.openCount ?? 0;
  if (openTodoCount > 0) {
    const highPriorityCount = payload.todoSummary?.highPriorityCount ?? 0;
    items.push({
      key: "todo-open",
      title: `待办事项 ${openTodoCount} 条`,
      reason: highPriorityCount > 0
        ? `其中 ${highPriorityCount} 条是高优先级，需要先确认。`
        : "这些事项已分配给你，需要继续推进。",
      meta: highPriorityCount > 0 ? "高优先级" : "个人待办",
      href: payload.todoSummary?.href ?? "/todos",
      actionLabel: "查看待办",
      severity: highPriorityCount > 0 ? "high" : "normal",
      icon: "check_circle",
      priority: 90,
      count: openTodoCount,
    });
  }

  if (payload.weeklyReport?.status === "draft") {
    items.push({
      key: "weekly-draft",
      title: "本周周报待填写",
      reason: "需要补充本周进展、风险和下周计划。",
      meta: "本周",
      href: payload.weeklyReport.href,
      actionLabel: "填写周报",
      severity: payload.weeklyReport.needsHelp ? "high" : "warning",
      icon: "article",
      priority: 72,
      count: 1,
    });
  }

  if (roleCapabilities.canUseFinance && payload.financeSummary) {
    if (payload.financeSummary.failedItemCount > 0) {
      items.push({
        key: "finance-failed-payment",
        title: `异常付款 ${payload.financeSummary.failedItemCount} 项`,
        reason: "付款失败或异常需要财务确认原因。",
        meta: "财务异常",
        href: payload.financeSummary.href,
        actionLabel: "处理异常",
        severity: "high",
        icon: "priority_high",
        priority: 96,
        count: payload.financeSummary.failedItemCount,
      });
    }

    if (payload.financeSummary.riskCount > 0) {
      items.push({
        key: "finance-risk-review",
        title: `待复核风险 ${payload.financeSummary.riskCount} 项`,
        reason: "付款或报销风险需要复核后再推进。",
        meta: "风险复核",
        href: payload.financeSummary.href,
        actionLabel: "去复核",
        severity: "high",
        icon: "shield_person",
        priority: 94,
        count: payload.financeSummary.riskCount,
      });
    }

    if (payload.financeSummary.pendingBatchCount > 0) {
      items.push({
        key: "finance-pending-batch",
        title: `待付款批次 ${payload.financeSummary.pendingBatchCount} 个`,
        reason: "需要继续确认、复核或提交付款。",
        meta: "付款",
        href: payload.financeSummary.href,
        actionLabel: "处理付款",
        severity: "warning",
        icon: "payments",
        priority: 86,
        count: payload.financeSummary.pendingBatchCount,
      });
    }
  }

  if (payload.projectSummary?.highPriorityTaskCount) {
    items.push({
      key: "project-high-priority",
      title: `高优先级项目任务 ${payload.projectSummary.highPriorityTaskCount} 项`,
      reason: "项目动作需要今天确认下一步。",
      meta: "项目",
      href: payload.projectSummary.href,
      actionLabel: "查看项目",
      severity: "warning",
      icon: "workspaces",
      priority: 64,
      count: payload.projectSummary.highPriorityTaskCount,
    });
  }

  if (payload.projectSummary?.followUpDueTodayCount) {
    items.push({
      key: "project-follow-up",
      title: `今日项目跟进 ${payload.projectSummary.followUpDueTodayCount} 项`,
      reason: "客户、交付或验收动作今天需要跟进。",
      meta: "今日",
      href: payload.projectSummary.href,
      actionLabel: "去跟进",
      severity: "warning",
      icon: "event_upcoming",
      priority: 62,
      count: payload.projectSummary.followUpDueTodayCount,
    });
  }

  return uniqueWorkItems(items).slice(0, 8);
}

function buildProgressItems(payload: PortalHomePayload) {
  const items: WorkItem[] = [];

  if (payload.weeklyReport?.status === "submitted") {
    items.push({
      key: "weekly-submitted",
      title: "本周周报已提交",
      reason: "本周进展已记录，可进入周报页查看。",
      meta: "已提交",
      href: payload.weeklyReport.href,
      actionLabel: "查看",
      severity: "normal",
      icon: "done_all",
      priority: 30,
      count: 1,
    });
  }

  return uniqueWorkItems(items).slice(0, 3);
}

function buildTeamBlockers(payload: PortalHomePayload, roleCapabilities: RoleCapabilities) {
  if (!roleCapabilities.canViewTeam && !roleCapabilities.canManageSystem) {
    return [];
  }

  const items: WorkItem[] = [];

  if ((payload.weeklySummary?.missingCount ?? 0) > 0) {
    items.push({
      key: "team-weekly-missing",
      title: `${payload.weeklySummary?.missingCount ?? 0} 人未交周报`,
      reason: "负责人需要提醒或确认是否有阻塞。",
      meta: "团队",
      href: payload.weeklySummary?.href ?? "/weekly-reports",
      actionLabel: "查看周报",
      severity: "warning",
      icon: "article",
      priority: 78,
      count: payload.weeklySummary?.missingCount ?? 0,
    });
  }

  if ((payload.weeklySummary?.needsHelpCount ?? 0) > 0) {
    items.push({
      key: "team-weekly-help",
      title: `${payload.weeklySummary?.needsHelpCount ?? 0} 人标记需要协助`,
      reason: "需要负责人确认问题和下一步支持。",
      meta: "协助",
      href: payload.weeklySummary?.href ?? "/weekly-reports",
      actionLabel: "查看详情",
      severity: "high",
      icon: "support_agent",
      priority: 82,
      count: payload.weeklySummary?.needsHelpCount ?? 0,
    });
  }

  if ((payload.teamPresence?.unspecified ?? 0) > 0) {
    items.push({
      key: "team-presence-missing",
      title: `${payload.teamPresence?.unspecified ?? 0} 人未更新团队状态`,
      reason: "今日在岗、外出或请假状态还不完整。",
      meta: "状态",
      href: payload.teamPresence?.href ?? "/team",
      actionLabel: "查看团队",
      severity: "warning",
      icon: "groups",
      priority: 58,
      count: payload.teamPresence?.unspecified ?? 0,
    });
  }

  if ((payload.projectSummary?.overdueMilestonesCount ?? 0) > 0) {
    items.push({
      key: "team-project-overdue",
      title: `${payload.projectSummary?.overdueMilestonesCount ?? 0} 个里程碑已逾期`,
      reason: "项目负责人需要调整计划或补充说明。",
      meta: "项目",
      href: payload.projectSummary?.href ?? "/projects",
      actionLabel: "查看项目",
      severity: "warning",
      icon: "flag",
      priority: 74,
      count: payload.projectSummary?.overdueMilestonesCount ?? 0,
    });
  }

  if ((payload.projectSummary?.openRiskCount ?? 0) > 0) {
    items.push({
      key: "team-project-risk",
      title: `${payload.projectSummary?.openRiskCount ?? 0} 个项目风险未关闭`,
      reason: "需要确认风险责任人、应对措施和截止时间。",
      meta: "风险",
      href: payload.projectSummary?.href ?? "/projects",
      actionLabel: "处理风险",
      severity: "high",
      icon: "warning",
      priority: 76,
      count: payload.projectSummary?.openRiskCount ?? 0,
    });
  }

  if ((payload.peopleLifecycle?.offboardingCount ?? 0) > 0 || (payload.peopleLifecycle?.assetReturnPendingCount ?? 0) > 0) {
    items.push({
      key: "team-offboarding-assets",
      title: "离职和资产交接待收口",
      reason: `离职 ${payload.peopleLifecycle?.offboardingCount ?? 0} 条，资产 ${payload.peopleLifecycle?.assetReturnPendingCount ?? 0} 项。`,
      meta: "交接",
      href: payload.peopleLifecycle?.href ?? "/people",
      actionLabel: "查看人员",
      severity: "warning",
      icon: "inventory_2",
      priority: 60,
      count: (payload.peopleLifecycle?.offboardingCount ?? 0) + (payload.peopleLifecycle?.assetReturnPendingCount ?? 0),
    });
  }

  return uniqueWorkItems(items).slice(0, 3);
}

function buildManagementReminders(
  payload: PortalHomePayload,
  roleCapabilities: RoleCapabilities,
  canSetupWorkspace: boolean,
) {
  if (!roleCapabilities.canManageSystem) {
    return [];
  }

  const items: WorkItem[] = [];

  if (!payload.workspace.persisted && canSetupWorkspace) {
    items.push({
      key: "workspace-setup",
      title: "工作区设置未完成",
      reason: "需要确认基础入口、通知策略和可见模块。",
      meta: "配置",
      href: "/system/workspace",
      actionLabel: "去设置",
      severity: "warning",
      icon: "settings",
      priority: 88,
      count: 1,
    });
  }

  const inactiveLoginCount = payload.adoptionSummary
    ? Math.max(0, payload.adoptionSummary.activeEmployeeCount - payload.adoptionSummary.login7dCount)
    : 0;
  if (inactiveLoginCount > 0) {
    items.push({
      key: "trial-login-missing",
      title: `近 7 天 ${inactiveLoginCount} 人未登录`,
      reason: "试运行覆盖率不足，需要确认账号或提醒到人。",
      meta: "试运行",
      href: "/system/workspace",
      actionLabel: "查看配置",
      severity: "warning",
      icon: "manage_accounts",
      priority: 52,
      count: inactiveLoginCount,
    });
  }

  return uniqueWorkItems(items).slice(0, 3);
}

function buildEmptyActions(permissions: string[], roleCapabilities: RoleCapabilities) {
  const actions: EmptyAction[] = [];

  if (!roleCapabilities.isAdminOnly && hasAnyPermission(permissions, EXPENSE_PORTAL_PERMISSIONS)) {
    actions.push({ key: "new-expense", label: "新建报销", href: "/reimbursements", variant: "primary" });
    actions.push({ key: "my-progress", label: "查看进度", href: "/reimbursements", variant: "secondary" });
  }

  if (roleCapabilities.canManageSystem) {
    actions.push({ key: "manage-settings", label: "管理设置", href: "/system/workspace", variant: actions.length ? "ghost" : "secondary" });
  }

  return actions.slice(0, roleCapabilities.canManageSystem && actions.length > 2 ? 3 : 2);
}

function buildQuickEntries(permissions: string[], roleCapabilities: RoleCapabilities) {
  const entries: QuickEntry[] = [];

  if (!roleCapabilities.isAdminOnly && hasAnyPermission(permissions, EXPENSE_PORTAL_PERMISSIONS)) {
    entries.push({
      key: "reimbursements",
      label: "报销",
      href: "/reimbursements",
      actionLabel: hasAnyPermission(permissions, ["expense.create", "expense.proxy_manage"]) ? "新建报销" : "查看报销",
      icon: "request_quote",
    });
  }

  if (hasAnyPermission(permissions, PROCUREMENT_PORTAL_PERMISSIONS)) {
    entries.push({
      key: "purchase",
      label: "采购",
      href: "/purchase-requests",
      actionLabel: hasAnyPermission(permissions, ["procurement.create", "procurement.submit"]) ? "新建采购" : "查看采购",
      icon: "shopping_cart",
    });
  }

  if (hasAnyPermission(permissions, CONTRACT_PORTAL_PERMISSIONS)) {
    entries.push({
      key: "contracts",
      label: "合同",
      href: "/contracts-registry",
      actionLabel: "查看合同",
      icon: "description",
    });
  }

  if (hasAnyPermission(permissions, PROJECT_PORTAL_PERMISSIONS)) {
    entries.push({
      key: "projects",
      label: "项目",
      href: "/projects",
      actionLabel: "查看项目",
      icon: "workspaces",
    });
  }

  if (hasAnyPermission(permissions, ASSET_PORTAL_PERMISSIONS)) {
    entries.push({
      key: "assets",
      label: "资产",
      href: "/assets",
      actionLabel: "查看资产",
      icon: "inventory_2",
    });
  }

  if (roleCapabilities.canUseFinance) {
    entries.push({
      key: "payments",
      label: "付款",
      href: "/payment-batches",
      actionLabel: "处理付款",
      icon: "payments",
    });
  }

  if (hasAnyPermission(permissions, INVOICE_PORTAL_PERMISSIONS)) {
    entries.push({
      key: "invoices",
      label: "票据",
      href: "/invoice-pool",
      actionLabel: "查看票据",
      icon: "receipt_long",
    });
  }

  return entries.slice(0, 6);
}

function sumWorkItemCount(items: WorkItem[]) {
  return items.reduce((total, item) => total + Math.max(1, item.count), 0);
}

function SummaryStrip({
  userName,
  actionCount,
  progressCount,
  blockerCount,
  reminderCount,
}: {
  userName: string;
  actionCount: number;
  progressCount: number;
  blockerCount: number;
  reminderCount: number;
}) {
  const attentionCount = blockerCount + reminderCount;
  const summaryParts = [`待处理 ${actionCount}`];
  if (progressCount > 0) summaryParts.push(`进度 ${progressCount}`);
  if (attentionCount > 0) summaryParts.push(`提醒 ${attentionCount}`);
  const summaryText = summaryParts.join(" · ");

  return (
    <section className="portal-work-summary" data-testid="portal-work-summary">
      <div className="min-w-0">
        <div className="portal-work-summary__title">{summaryText}</div>
        <div className="portal-work-summary__meta">{userName} · 当前工作区</div>
      </div>
    </section>
  );
}

function WorkItemRow({ item }: { item: WorkItem }) {
  const severityClass = item.severity === "high"
    ? "portal-task-row portal-task-row--high"
    : item.severity === "warning"
      ? "portal-task-row portal-task-row--warning"
      : "portal-task-row";

  return (
    <Link to={item.href} className={severityClass}>
      <span className="portal-task-row__icon" aria-hidden="true">
        <span className="material-symbols-outlined text-[18px]">{item.icon}</span>
      </span>
      <span className="min-w-0 flex-1">
        <span className="portal-task-row__title">{item.title}</span>
      </span>
      <span className="portal-task-row__meta">{item.meta}</span>
      <span className="portal-task-row__action">{item.actionLabel}</span>
    </Link>
  );
}

function WorkItemList({ items }: { items: WorkItem[] }) {
  return (
    <div className="portal-task-list">
      {items.map((item) => (
        <WorkItemRow key={item.key} item={item} />
      ))}
    </div>
  );
}

function QuickEntryPanel({ entries }: { entries: QuickEntry[] }) {
  if (!entries.length) {
    return null;
  }

  return (
    <SectionPanel title="常用入口">
      <div className="portal-quick-entry-grid" data-testid="portal-quick-entries">
        {entries.map((entry) => (
          <Link className="portal-quick-entry" key={entry.key} to={entry.href}>
            <span className="portal-quick-entry__icon" aria-hidden="true">
              <span className="material-symbols-outlined text-[18px]">{entry.icon}</span>
            </span>
            <span className="min-w-0">
              <span className="portal-quick-entry__title">{entry.label}</span>
            </span>
          </Link>
        ))}
      </div>
    </SectionPanel>
  );
}

function TodayActionPanel({
  items,
  emptyActions,
}: {
  items: WorkItem[];
  emptyActions: EmptyAction[];
}) {
  return (
    <SectionPanel title="今日待处理" className="portal-panel-fill">
      {items.length ? (
        <WorkItemList items={items} />
      ) : (
        <div className="portal-empty-start">
          <div>
            <div className="portal-empty-start__title">暂无待处理</div>
          </div>
          {emptyActions.length ? (
            <div className="portal-inline-actions">
              {emptyActions.map((action) => (
                <Button
                  key={action.key}
                  asChild
                  type="button"
                  variant={action.variant === "primary" ? "default" : action.variant ?? "secondary"}
                >
                  <Link to={action.href}>{action.label}</Link>
                </Button>
              ))}
            </div>
          ) : null}
        </div>
      )}
    </SectionPanel>
  );
}

function ConditionalWorkPanel({
  title,
  items,
}: {
  title: string;
  items: WorkItem[];
}) {
  if (!items.length) {
    return null;
  }

  return (
    <SectionPanel title={title}>
      <WorkItemList items={items} />
    </SectionPanel>
  );
}

export function PortalHomePage() {
  const { me, permissions } = useAuth();
  const [showWelcome, setShowWelcome] = useState(false);
  const portalQuery = useQuery({ queryKey: ["portal-home"], queryFn: () => fetchPortalHome() });
  const canSetupWorkspace = hasAnyPermission(permissions, ["system.settings"]);

  useEffect(() => {
    setShowWelcome(shouldShowWelcomeDialog());
  }, []);

  if (portalQuery.isLoading) {
    return <div className="card-std p-5 text-sm text-zinc-500">加载工作台中...</div>;
  }

  if (portalQuery.isError || !portalQuery.data) {
    const message = isApiError(portalQuery.error)
      ? `${portalQuery.error.code}: ${mapApiErrorMessage(portalQuery.error.code, portalQuery.error.details, portalQuery.error.message)}`
      : "工作台加载失败";
    return <div className="card-std p-5 text-sm text-red-600">{message}</div>;
  }

  const payload = portalQuery.data;
  const roleCapabilities = payload.roleCapabilities ?? buildFallbackRoleCapabilities(permissions, me?.roleCodes ?? []);
  const isManagerView =
    roleCapabilities.canViewTeam ||
    roleCapabilities.canApproveTasks ||
    roleCapabilities.canUseFinance ||
    roleCapabilities.canManageSystem ||
    isManagerRole(permissions);
  const todayActionItems = buildTodayActionItems(payload, roleCapabilities);
  const quickEntries = buildQuickEntries(permissions, roleCapabilities);
  const progressItems = buildProgressItems(payload);
  const teamBlockers = isManagerView ? buildTeamBlockers(payload, roleCapabilities) : [];
  const managementReminders = buildManagementReminders(payload, roleCapabilities, canSetupWorkspace);
  const emptyActions = buildEmptyActions(permissions, roleCapabilities);
  const actionCount = sumWorkItemCount(todayActionItems);
  const progressCount = sumWorkItemCount(progressItems);
  const blockerCount = sumWorkItemCount(teamBlockers);
  const reminderCount = sumWorkItemCount(managementReminders);

  function handleCloseWelcome() {
    clearWelcomeDialogFlag();
    setShowWelcome(false);
  }

  return (
    <PageScaffold>
      <ErrorBoundary fallback={null}>
        <WelcomeDialog open={showWelcome} onClose={handleCloseWelcome} />
      </ErrorBoundary>

      <SummaryStrip
        userName={payload.greeting.name}
        actionCount={actionCount}
        progressCount={progressCount}
        blockerCount={blockerCount}
        reminderCount={reminderCount}
      />

      <QuickEntryPanel entries={quickEntries} />

      <TodayActionPanel items={todayActionItems} emptyActions={emptyActions} />

      <div className="portal-task-secondary-grid">
        <ConditionalWorkPanel title="我的进度" items={progressItems} />
        <ConditionalWorkPanel title="团队卡点" items={teamBlockers} />
        <ConditionalWorkPanel title="管理提醒" items={managementReminders} />
      </div>
    </PageScaffold>
  );
}