import { useState, useEffect, useCallback } from 'react';
import { message } from 'antd';
import type { FormInstance } from 'antd';
import type { Dataset, RetrievalModel } from '~/api/dify-dataset/type/datasetTypes';
import { updateDatasetSettings, fetchDataset } from '~/api/dify-dataset/api/datasetApi';
import { DIFY_CONFIG } from '~/config/api-config';

/**
 * 检索方法类型
 */
export type SearchMethod = 'keyword_search' | 'semantic_search' | 'full_text_search' | 'hybrid_search';

/**
 * 检索设置表单值
 */
export interface RetrievalSettingsFormValues {
    searchMethod: SearchMethod;
    topK: number;
    scoreThresholdEnabled: boolean;
    scoreThreshold: number;
    rerankingEnable: boolean;
    weights: number; // 混合检索的语义权重 (0-1)
}

/**
 * 默认检索设置
 */
const DEFAULT_RETRIEVAL_SETTINGS: RetrievalSettingsFormValues = {
    searchMethod: 'semantic_search',
    topK: 3,
    scoreThresholdEnabled: true,  // 默认开启
    scoreThreshold: 0.5,
    rerankingEnable: true,        // 默认开启
    weights: 0.7,
};

/**
 * 从 Dataset 的 retrieval_model 转换为表单值
 */
function retrievalModelToFormValues(model?: RetrievalModel): RetrievalSettingsFormValues {
    if (!model) {
        return { ...DEFAULT_RETRIEVAL_SETTINGS };
    }
    return {
        searchMethod: model.search_method || 'semantic_search',
        topK: model.top_k ?? 3,
        scoreThresholdEnabled: model.score_threshold_enabled ?? false,
        scoreThreshold: model.score_threshold ?? 0.5,
        rerankingEnable: model.reranking_enable ?? false,
        weights: model.weights ?? 0.7,
    };
}

/**
 * 从表单值转换为 API 请求的 retrieval_model
 */
function formValuesToRetrievalModel(values: RetrievalSettingsFormValues): RetrievalModel {
    // 语义检索和混合检索需要 Reranking，强制开启
    const needReranking = values.searchMethod === 'semantic_search' || values.searchMethod === 'hybrid_search';

    return {
        search_method: values.searchMethod,
        reranking_enable: needReranking,  // 强制开启，不受用户控制
        reranking_mode: null,
        reranking_model: {
            reranking_provider_name: DIFY_CONFIG.rerankingProviderName,
            reranking_model_name: DIFY_CONFIG.rerankingModelName,
        },
        weights: values.searchMethod === 'hybrid_search' ? values.weights : null,
        top_k: values.topK,
        score_threshold_enabled: true,    // 强制开启，不受用户控制
        score_threshold: values.scoreThreshold,  // 用户可调节数值
    };
}

/**
 * 知识库设置状态管理 Hook
 */
export function useDatasetSettings(
    dataset: Dataset | null,
    form: FormInstance,
    onDatasetUpdated: (dataset: Dataset) => void
) {
    const [saving, setSaving] = useState(false);
    const [hasChanges, setHasChanges] = useState(false);

    // 检索设置状态（注意：Dify API 返回的字段名是 retrieval_model_dict）
    const [retrievalSettings, setRetrievalSettings] = useState<RetrievalSettingsFormValues>(
        () => retrievalModelToFormValues(dataset?.retrieval_model_dict)
    );

    // 初始化表单数据
    useEffect(() => {
        if (dataset) {
            form.setFieldsValue({
                name: dataset.name,
                description: dataset.description || '',
            });
            console.log('[DatasetSettings] 初始化检索设置, retrieval_model_dict:', dataset.retrieval_model_dict);
            setRetrievalSettings(retrievalModelToFormValues(dataset.retrieval_model_dict));
            setHasChanges(false);
        }
    }, [dataset, form]);

    /**
     * 更新检索设置
     */
    const updateRetrievalSettings = useCallback(<K extends keyof RetrievalSettingsFormValues>(
        key: K,
        value: RetrievalSettingsFormValues[K]
    ) => {
        setRetrievalSettings(prev => {
            const newSettings = { ...prev, [key]: value };
            // 检查是否有变化
            checkForChanges(newSettings);
            return newSettings;
        });
    }, [dataset]);

    /**
     * 检查是否有变化
     */
    const checkForChanges = useCallback((newRetrievalSettings?: RetrievalSettingsFormValues) => {
        const values = form.getFieldsValue();
        const currentRetrieval = newRetrievalSettings || retrievalSettings;
        const originalRetrieval = retrievalModelToFormValues(dataset?.retrieval_model_dict);

        const nameChanged = values.name !== dataset?.name;
        const retrievalChanged =
            currentRetrieval.searchMethod !== originalRetrieval.searchMethod ||
            currentRetrieval.topK !== originalRetrieval.topK ||
            currentRetrieval.scoreThresholdEnabled !== originalRetrieval.scoreThresholdEnabled ||
            currentRetrieval.scoreThreshold !== originalRetrieval.scoreThreshold ||
            currentRetrieval.rerankingEnable !== originalRetrieval.rerankingEnable ||
            currentRetrieval.weights !== originalRetrieval.weights;

        setHasChanges(nameChanged || retrievalChanged);
    }, [form, dataset, retrievalSettings]);

    /**
     * 处理表单值变化
     */
    const handleValuesChange = useCallback(() => {
        checkForChanges();
    }, [checkForChanges]);

    /**
     * 保存设置
     */
    const handleSave = useCallback(async () => {
        if (!dataset) {
            message.error('知识库不存在');
            return;
        }

        try {
            const values = await form.validateFields();
            setSaving(true);

            // 构建完整的更新请求
            await updateDatasetSettings(dataset.id, {
                name: values.name,
                retrieval_model: formValuesToRetrievalModel(retrievalSettings),
            });

            // PATCH 接口返回的数据可能不完整，重新获取详情
            const fullDataset = await fetchDataset(dataset.id);
            console.log('[DatasetSettings] 保存后获取完整数据:', fullDataset);

            message.success('保存成功');
            onDatasetUpdated(fullDataset);
            setHasChanges(false);
        } catch (err: any) {
            console.error('保存设置失败:', err);
            message.error(err.message || '保存失败');
        } finally {
            setSaving(false);
        }
    }, [dataset, form, retrievalSettings, onDatasetUpdated]);

    /**
     * 重置表单
     */
    const handleReset = useCallback(() => {
        if (dataset) {
            form.setFieldsValue({
                name: dataset.name,
                description: dataset.description || '',
            });
            setRetrievalSettings(retrievalModelToFormValues(dataset.retrieval_model_dict));
            setHasChanges(false);
        }
    }, [dataset, form]);

    return {
        // 状态
        saving,
        hasChanges,
        retrievalSettings,

        // 方法
        handleValuesChange,
        handleSave,
        handleReset,
        updateRetrievalSettings,
    };
}

export type UseDatasetSettingsReturn = ReturnType<typeof useDatasetSettings>;