import { NextResponse } from 'next/server';
import fs from 'fs';
import { commit } from '@huggingface/hub';
import { HF_DATASET_ID, HF_DATASET_BASE_URL, getCorpus, getDocRepoPath, getDocLocalPath } from '../../../utils/config.js';

const isHFSpace = () => process.env.HF_TOKEN && process.env.NODE_ENV !== 'development';

/**
 * PUT /api/validate
 * Body: { corpus, document_index, page_number, dataset_index, updates }
 */
export async function PUT(request) {
    try {
        const { corpus: corpusId, document_index, page_number, dataset_index, updates } = await request.json();
        const corpus = getCorpus(corpusId);

        if (document_index == null || page_number == null || dataset_index == null || !updates) {
            return NextResponse.json(
                { error: 'Missing document_index, page_number, dataset_index, or updates' },
                { status: 400 }
            );
        }

        let pagesData;

        if (isHFSpace()) {
            const repoPath = getDocRepoPath(corpus, document_index);
            const url = `${HF_DATASET_BASE_URL}/raw/main/${repoPath}`;
            const res = await fetch(url, {
                headers: { 'Authorization': `Bearer ${process.env.HF_TOKEN}` }
            });
            if (!res.ok) {
                return NextResponse.json({ error: `Document not found on HF (${corpus.id})` }, { status: 404 });
            }
            pagesData = await res.json();
        } else {
            const filePath = getDocLocalPath(corpus, document_index);
            if (!fs.existsSync(filePath)) {
                return NextResponse.json({ error: `Document not found locally (${corpus.id})` }, { status: 404 });
            }
            pagesData = JSON.parse(fs.readFileSync(filePath, 'utf-8'));
        }

        const pageIdx = pagesData.findIndex(p => p.document?.pages?.[0] === page_number);
        if (pageIdx === -1) {
            return NextResponse.json({ error: `Page ${page_number} not found` }, { status: 404 });
        }

        const datasets = pagesData[pageIdx].datasets || [];
        if (dataset_index < 0 || dataset_index >= datasets.length) {
            return NextResponse.json({ error: `Dataset index ${dataset_index} out of range` }, { status: 400 });
        }

        // Per-annotator validation
        const currentEntry = pagesData[pageIdx].datasets[dataset_index];
        const annotator = updates.annotator || 'unknown';
        const validationFields = ['human_validated', 'human_verdict', 'human_notes', 'annotator', 'validated_at'];
        const isValidation = validationFields.some(f => f in updates);

        if (isValidation) {
            const validations = currentEntry.validations || [];
            const existingIdx = validations.findIndex(v => v.annotator === annotator);
            const validationEntry = {
                human_validated: updates.human_validated,
                human_verdict: updates.human_verdict,
                human_notes: updates.human_notes || null,
                annotator,
                validated_at: updates.validated_at || new Date().toISOString(),
            };

            if (existingIdx >= 0) {
                validations[existingIdx] = validationEntry;
            } else {
                validations.push(validationEntry);
            }

            pagesData[pageIdx].datasets[dataset_index] = { ...currentEntry, validations };
        } else {
            pagesData[pageIdx].datasets[dataset_index] = { ...currentEntry, ...updates };
        }

        // Save back
        if (isHFSpace()) {
            const repoPath = getDocRepoPath(corpus, document_index);
            const content = JSON.stringify(pagesData, null, 2);
            await commit({
                repo: { type: 'dataset', name: HF_DATASET_ID },
                credentials: { accessToken: process.env.HF_TOKEN },
                title: `Validate ${corpus.id}/doc_${document_index} page ${page_number}`,
                operations: [{
                    operation: 'addOrUpdate',
                    path: repoPath,
                    content: new Blob([content], { type: 'application/json' }),
                }],
            });
        } else {
            const filePath = getDocLocalPath(corpus, document_index);
            fs.writeFileSync(filePath, JSON.stringify(pagesData, null, 2));
        }

        return NextResponse.json({
            success: true,
            dataset: pagesData[pageIdx].datasets[dataset_index],
        });
    } catch (error) {
        console.error('Validate error:', error);
        return NextResponse.json({ error: 'Failed to validate: ' + error.message }, { status: 500 });
    }
}

/**
 * DELETE /api/validate?corpus=X&doc=X&page=Y&idx=Z
 */
export async function DELETE(request) {
    try {
        const { searchParams } = new URL(request.url);
        const corpusId = searchParams.get('corpus');
        const document_index = parseInt(searchParams.get('doc'), 10);
        const page_number = parseInt(searchParams.get('page'), 10);
        const dataset_index = parseInt(searchParams.get('idx'), 10);

        const corpus = getCorpus(corpusId);

        if (isNaN(document_index) || isNaN(page_number) || isNaN(dataset_index)) {
            return NextResponse.json(
                { error: 'Missing doc, page, or idx parameter' },
                { status: 400 }
            );
        }

        let pagesData;

        if (isHFSpace()) {
            const repoPath = getDocRepoPath(corpus, document_index);
            const url = `${HF_DATASET_BASE_URL}/raw/main/${repoPath}`;
            const res = await fetch(url, {
                headers: { 'Authorization': `Bearer ${process.env.HF_TOKEN}` }
            });
            if (!res.ok) {
                return NextResponse.json({ error: `Document not found on HF (${corpus.id})` }, { status: 404 });
            }
            pagesData = await res.json();
        } else {
            const filePath = getDocLocalPath(corpus, document_index);
            if (!fs.existsSync(filePath)) {
                return NextResponse.json({ error: `Document not found locally (${corpus.id})` }, { status: 404 });
            }
            pagesData = JSON.parse(fs.readFileSync(filePath, 'utf-8'));
        }

        const pageIdx = pagesData.findIndex(p => p.document?.pages?.[0] === page_number);
        if (pageIdx === -1) {
            return NextResponse.json({ error: `Page ${page_number} not found` }, { status: 404 });
        }

        const datasets = pagesData[pageIdx].datasets || [];
        if (dataset_index < 0 || dataset_index >= datasets.length) {
            return NextResponse.json({ error: `Dataset index ${dataset_index} out of range` }, { status: 400 });
        }

        pagesData[pageIdx].datasets.splice(dataset_index, 1);

        if (isHFSpace()) {
            const repoPath = getDocRepoPath(corpus, document_index);
            const content = JSON.stringify(pagesData, null, 2);
            await commit({
                repo: { type: 'dataset', name: HF_DATASET_ID },
                credentials: { accessToken: process.env.HF_TOKEN },
                title: `Delete from ${corpus.id}/doc_${document_index} page ${page_number}`,
                operations: [{
                    operation: 'addOrUpdate',
                    path: repoPath,
                    content: new Blob([content], { type: 'application/json' }),
                }],
            });
        } else {
            const filePath = getDocLocalPath(corpus, document_index);
            fs.writeFileSync(filePath, JSON.stringify(pagesData, null, 2));
        }

        return NextResponse.json({ success: true });
    } catch (error) {
        console.error('Delete error:', error);
        return NextResponse.json({ error: 'Failed to delete: ' + error.message }, { status: 500 });
    }
}