/**
 * 自有 RAG Chat API 模块
 *
 * 保持前端 dify-chat 调用面不变，内部转发到新的 /api/v3/rag/* 接口。
 *
 * @module api/dify-chat/chat
 */

import { difyFetch } from './client.server';

function unwrapResult<T>(payload: any): T {
    if (payload && typeof payload === 'object' && 'data' in payload) {
        return payload.data as T;
    }
    return payload as T;
}

function toIntAppId(appId?: string): string | undefined {
    if (!appId) return undefined;
    const parsed = Number(appId);
    return Number.isFinite(parsed) ? String(parsed) : undefined;
}

function normalizeConversationName(name: string): string {
    const compact = (name || '').replace(/\s+/g, ' ').trim();
    if (!compact) return '新对话';
    return compact.length > 20 ? `${compact.slice(0, 20)}...` : compact;
}

export const difyClient = {
    async getApplicationParameters(jwt?: string, appId?: string): Promise<any> {
        const response = await difyFetch('chat/parameters', {
            method: 'GET',
            appId: toIntAppId(appId),
        }, jwt);
        const payload = unwrapResult<any>(await response.json());
        return {
            opening_statement: payload?.openingStatement || '',
            suggested_questions: payload?.suggestedQuestions || [],
            user_input_form: payload?.userInputForm || [],
            file_upload: payload?.fileUpload || { enabled: false },
        };
    },

    async getConversations(jwt?: string, appId?: string): Promise<any> {
        const params = new URLSearchParams({
            page: '1',
            pageSize: '100',
        });
        const normalizedAppId = toIntAppId(appId);
        if (normalizedAppId) {
            params.set('appId', normalizedAppId);
        }

        const response = await difyFetch(`chat/conversations?${params.toString()}`, {
            method: 'GET',
        }, jwt);
        const payload = unwrapResult<any>(await response.json());
        return {
            data: (payload?.data || []).map((item: any) => ({
                id: item.id,
                name: item.name,
                introduction: item.introduction || '',
                created_at: item.createdAt || 0,
                updated_at: item.updatedAt || 0,
            })),
            has_more: Boolean(payload?.hasMore),
            limit: payload?.limit || 100,
        };
    },

    async getConversationMessages(conversationId: string, jwt?: string): Promise<any> {
        const params = new URLSearchParams({
            page: '1',
            pageSize: '100',
        });
        const response = await difyFetch(`chat/conversations/${conversationId}/messages?${params.toString()}`, {
            method: 'GET',
        }, jwt);
        const payload = unwrapResult<any>(await response.json());
        return {
            data: (payload?.data || []).map((item: any) => ({
                id: item.id,
                query: item.query,
                answer: item.answer,
                feedback: item.feedback || undefined,
                retriever_resources: item.retrieverResources || [],
                created_at: item.createdAt || 0,
            })),
            has_more: Boolean(payload?.hasMore),
            limit: payload?.limit || 100,
        };
    },

    async createChatMessage(
        inputs: Record<string, any>,
        query: string,
        responseMode: string = 'streaming',
        conversationId?: string,
        files?: any[],
        jwt?: string,
        appId?: string
    ): Promise<Response | any> {
        const body = {
            inputs,
            query,
            response_mode: responseMode,
            conversation_id: conversationId,
            files: files || [],
            appId: toIntAppId(appId) ? Number(appId) : null,
            conversationId: conversationId || null,
        };
        const response = await difyFetch('chat/messages', {
            method: 'POST',
            body: JSON.stringify(body),
        }, jwt);

        if (responseMode === 'streaming') {
            return response;
        }

        return response.json();
    },

    async renameConversation(
        conversationId: string,
        name: string,
        autoGenerate: boolean = false,
        jwt?: string
    ): Promise<any> {
        let nextName = name?.trim() || '';

        if (autoGenerate || !nextName) {
            const messages = await this.getConversationMessages(conversationId, jwt);
            const firstQuestion = messages?.data?.find((item: any) => item?.query)?.query || '';
            nextName = normalizeConversationName(firstQuestion);
        }

        const response = await difyFetch(`chat/conversations/${conversationId}`, {
            method: 'PATCH',
            body: JSON.stringify({ name: nextName }),
        }, jwt);
        return unwrapResult<any>(await response.json());
    },

    async deleteConversation(conversationId: string, jwt?: string): Promise<any> {
        const response = await difyFetch(`chat/conversations/${conversationId}`, {
            method: 'DELETE',
        }, jwt);
        return unwrapResult<any>(await response.json());
    },

    async updateMessageFeedback(
        messageId: string,
        rating: 'like' | 'dislike' | null,
        jwt?: string
    ): Promise<any> {
        const response = await difyFetch(`chat/messages/${messageId}/feedback`, {
            method: 'POST',
            body: JSON.stringify({ rating }),
        }, jwt);
        return unwrapResult<any>(await response.json());
    },
};