import { useMemo, useState } from "react";
import { toPageQuery } from "@/shared/api/query";
import { usePaginatedQuery } from "@/shared/hooks/usePaginatedQuery.js";
import { useRegionOptions } from "@/shared/hooks/useRegionOptions.js";
import { useToast } from "@/shared/ui/ToastProvider.jsx";
import {
    createPolicyInstance,
    listPolicyInstances,
    listPolicyTemplates,
    publishPolicyInstance,
    savePolicyTemplate,
    updatePolicyInstanceStatus,
} from "@/features/policy-config/api";
import { usePolicyConfigAbilities } from "@/features/policy-config/permissions.js";
import {
    policyInstanceFormFromTemplate,
    policyInstancePayloadFromForm,
    policyTemplateFormFromItem,
    policyTemplatePayloadFromForm,
} from "@/features/policy-config/schema";

const pageSize = 50;

export function usePolicyConfigPage() {
    const abilities = usePolicyConfigAbilities();
    const { showToast } = useToast();
    const { loadingRegions, regionOptions } = useRegionOptions();
    const [activeTab, setActiveTab] = useState("templates");
    const [templateKeyword, setTemplateKeyword] = useState("");
    const [templateStatus, setTemplateStatus] = useState("");
    const [templatePage, setTemplatePage] = useState(1);
    const [instanceKeyword, setInstanceKeyword] = useState("");
    const [instanceStatus, setInstanceStatus] = useState("");
    const [instancePage, setInstancePage] = useState(1);
    const [templateDrawerOpen, setTemplateDrawerOpen] = useState(false);
    const [instanceDrawerOpen, setInstanceDrawerOpen] = useState(false);
    const [editingTemplate, setEditingTemplate] = useState(null);
    const [templateForm, setTemplateForm] = useState(() => policyTemplateFormFromItem(null));
    const [instanceForm, setInstanceForm] = useState(() => policyInstanceFormFromTemplate(null));
    const [loadingAction, setLoadingAction] = useState("");

    const templateFilters = useMemo(
        () => ({ keyword: templateKeyword, status: templateStatus }),
        [templateKeyword, templateStatus],
    );
    const instanceFilters = useMemo(
        () => ({ keyword: instanceKeyword, status: instanceStatus }),
        [instanceKeyword, instanceStatus],
    );

    const templates = usePaginatedQuery({
        errorMessage: "加载收益政策模板失败",
        fetcher: listPolicyTemplates,
        filters: templateFilters,
        page: templatePage,
        pageSize,
        queryKey: ["policy-templates", toPageQuery({ ...templateFilters, page: templatePage, pageSize })],
    });

    const instances = usePaginatedQuery({
        errorMessage: "加载收益政策实例失败",
        fetcher: listPolicyInstances,
        filters: instanceFilters,
        page: instancePage,
        pageSize,
        queryKey: ["policy-instances", toPageQuery({ ...instanceFilters, page: instancePage, pageSize })],
    });

    const templateOptions = useMemo(
        () =>
            (templates.data.items || []).map((template) => ({
                label: `${template.name || template.templateCode} · ${template.templateVersion}`,
                templateCode: template.templateCode,
                templateVersion: template.templateVersion,
                value: `${template.templateCode}:${template.templateVersion}`,
            })),
        [templates.data.items],
    );

    const regionLabelMap = useMemo(
        () =>
            regionOptions.reduce((labels, region) => {
                labels[String(region.regionId)] = region.label;
                return labels;
            }, {}),
        [regionOptions],
    );

    const openTemplateEditor = (template = null) => {
        setEditingTemplate(template);
        setTemplateForm(policyTemplateFormFromItem(template));
        setTemplateDrawerOpen(true);
    };

    const closeTemplateDrawer = () => {
        if (loadingAction === "template-save") {
            return;
        }
        setTemplateDrawerOpen(false);
        setEditingTemplate(null);
    };

    const openInstanceCreator = (template = null) => {
        setInstanceForm(policyInstanceFormFromTemplate(template || templates.data.items?.[0] || null));
        setInstanceDrawerOpen(true);
    };

    const closeInstanceDrawer = () => {
        if (loadingAction === "instance-create") {
            return;
        }
        setInstanceDrawerOpen(false);
    };

    const submitTemplate = async (event) => {
        event.preventDefault();
        if (!abilities.canSaveTemplate) {
            return;
        }
        await runAction("template-save", "收益政策模板已保存", async () => {
            // 模板 POST 是 code+version 维度的 upsert；保存只更新 admin 草稿，运行侧必须再发布实例。
            await savePolicyTemplate(policyTemplatePayloadFromForm(templateForm));
            setTemplateDrawerOpen(false);
            setEditingTemplate(null);
            await templates.reload();
        });
    };

    const submitInstance = async (event) => {
        event.preventDefault();
        if (!abilities.canCreateInstance) {
            return;
        }
        await runAction("instance-create", "收益政策实例已创建", async () => {
            // app_code 不在表单中提交，由 apiRequest 的 X-App-Code 和 admin-server appctx 共同确定。
            await createPolicyInstance(policyInstancePayloadFromForm(instanceForm));
            setInstanceDrawerOpen(false);
            await instances.reload();
        });
    };

    const toggleInstanceStatus = async (instance, nextEnabled = instance.status !== "active") => {
        if (!instance?.instanceId || !abilities.canUpdateInstance || (instance.status === "active") === nextEnabled) {
            return;
        }
        await runAction(`instance-status-${instance.instanceId}`, nextEnabled ? "收益政策实例已启用" : "收益政策实例已停用", async () => {
            // 停用实例要同步 owner service 运行表；不能只在前端隐藏。
            await updatePolicyInstanceStatus(instance.instanceId, nextEnabled ? "active" : "disabled");
            await instances.reload();
        });
    };

    const publishInstance = async (instance) => {
        if (!instance?.instanceId || !abilities.canPublishInstance) {
            return;
        }
        await runAction(`instance-publish-${instance.instanceId}`, "收益政策实例已发布", async () => {
            // 发布是 admin 配置进入 wallet/activity runtime 的唯一入口；模板保存本身不会影响线上结算。
            await publishPolicyInstance(instance.instanceId);
            await instances.reload();
        });
    };

    const changeTemplateKeyword = (value) => {
        setTemplateKeyword(value);
        setTemplatePage(1);
    };

    const changeTemplateStatus = (value) => {
        setTemplateStatus(value);
        setTemplatePage(1);
    };

    const changeInstanceKeyword = (value) => {
        setInstanceKeyword(value);
        setInstancePage(1);
    };

    const changeInstanceStatus = (value) => {
        setInstanceStatus(value);
        setInstancePage(1);
    };

    const resetTemplateFilters = () => {
        setTemplateKeyword("");
        setTemplateStatus("");
        setTemplatePage(1);
    };

    const resetInstanceFilters = () => {
        setInstanceKeyword("");
        setInstanceStatus("");
        setInstancePage(1);
    };

    const runAction = async (action, successMessage, submitter) => {
        setLoadingAction(action);
        try {
            await submitter();
            showToast(successMessage, "success");
        } catch (error) {
            showToast(error?.message || "操作失败", "error");
        } finally {
            setLoadingAction("");
        }
    };

    return {
        abilities,
        activeTab,
        changeInstanceKeyword,
        changeInstanceStatus,
        changeTemplateKeyword,
        changeTemplateStatus,
        closeInstanceDrawer,
        closeTemplateDrawer,
        editingTemplate,
        instanceDrawerOpen,
        instanceFilters: { keyword: instanceKeyword, status: instanceStatus },
        instanceForm,
        instancePage,
        instances,
        loadingAction,
        loadingRegions,
        openInstanceCreator,
        openTemplateEditor,
        publishInstance,
        regionLabelMap,
        regionOptions,
        resetInstanceFilters,
        resetTemplateFilters,
        setActiveTab,
        setInstanceForm,
        setInstancePage,
        setTemplateForm,
        setTemplatePage,
        submitInstance,
        submitTemplate,
        templateDrawerOpen,
        templateFilters: { keyword: templateKeyword, status: templateStatus },
        templateForm,
        templateOptions,
        templatePage,
        templates,
        toggleInstanceStatus,
    };
}