/**
 * Sources Routes
 * Manage data sources
 */

const express = require('express');
const multer = require('multer');
const { parse } = require('csv-parse/sync');
const { lit, arr } = require('../lib/sql');

const upload = multer({ storage: multer.memoryStorage() });

module.exports = (pool) => {
    const router = express.Router();

    // Global import log (all sources)
    router.get('/import-log', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM get_all_import_logs()`);
            res.json(result.rows);
        } catch (err) {
            next(err);
        }
    });

    // List all sources
    router.get('/', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM list_sources()`);
            res.json(result.rows);
        } catch (err) {
            next(err);
        }
    });

    // Get single source
    router.get('/:name', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM get_source(${lit(req.params.name)})`);
            if (result.rows.length === 0) return res.status(404).json({ error: 'Source not found' });
            res.json(result.rows[0]);
        } catch (err) {
            next(err);
        }
    });

    // Suggest source definition from CSV
    router.post('/suggest', upload.single('file'), async (req, res, next) => {
        try {
            if (!req.file) return res.status(400).json({ error: 'No file uploaded' });

            const records = parse(req.file.buffer, { columns: true, skip_empty_lines: true, trim: true });
            if (records.length === 0) return res.status(400).json({ error: 'CSV file is empty' });

            const ISO_DATE_RE = /^\d{4}-\d{2}-\d{2}(T[\d:.Z+-]+)?$/;
            const sample = records[0];
            const sampleRows = records.slice(0, 50);

            const fields = Object.keys(sample).map(key => {
                const vals = sampleRows.map(r => r[key]).filter(v => v !== '' && v != null);
                let type = 'text';
                if (vals.length > 0 && vals.every(v => !isNaN(parseFloat(v)) && isFinite(v) && String(v).charAt(0) !== '0')) {
                    type = 'numeric';
                } else if (vals.length > 0 && vals.every(v => ISO_DATE_RE.test(String(v)))) {
                    type = 'date';
                }
                return { name: key, type };
            });

            res.json({ name: '', constraint_fields: [], fields, sampleRows });
        } catch (err) {
            next(err);
        }
    });

    // Create source
    router.post('/', async (req, res, next) => {
        try {
            const { name, constraint_fields, config, global_picklist } = req.body;
            if (!name || !constraint_fields || !Array.isArray(constraint_fields)) {
                return res.status(400).json({ error: 'Missing required fields: name, constraint_fields (array)' });
            }
            const result = await pool.query(
                `SELECT * FROM create_source(${lit(name)}, ${arr(constraint_fields)}, ${lit(config || {})}, ${lit(global_picklist !== false)})`
            );
            res.status(201).json(result.rows[0]);
        } catch (err) {
            if (err.code === '23505') return res.status(409).json({ error: 'Source already exists' });
            next(err);
        }
    });

    // Update source
    router.put('/:name', async (req, res, next) => {
        try {
            const { constraint_fields, config, global_picklist } = req.body;
            const gpVal = global_picklist !== undefined ? lit(global_picklist) : 'NULL';
            const result = await pool.query(
                `SELECT * FROM update_source(${lit(req.params.name)}, ${constraint_fields ? arr(constraint_fields) : 'NULL'}, ${config ? lit(config) : 'NULL'}, ${gpVal})`
            );
            if (result.rows.length === 0) return res.status(404).json({ error: 'Source not found' });
            res.json(result.rows[0]);
        } catch (err) {
            next(err);
        }
    });

    // Delete source
    router.delete('/:name', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM delete_source(${lit(req.params.name)})`);
            if (result.rows.length === 0) return res.status(404).json({ error: 'Source not found' });
            res.json({ success: true, deleted: result.rows[0].delete_source });
        } catch (err) {
            next(err);
        }
    });

    // Import CSV data and apply transformations to new records
    router.post('/:name/import', upload.single('file'), async (req, res, next) => {
        try {
            if (!req.file) return res.status(400).json({ error: 'No file uploaded' });
            const records = parse(req.file.buffer, { columns: true, skip_empty_lines: true, trim: true });
            const importResult = await pool.query(
                `SELECT import_records(${lit(req.params.name)}, ${lit(records)}) as result`
            );
            const importData = importResult.rows[0].result;

            if (!importData.success) return res.json(importData);

            const transformResult = await pool.query(
                `SELECT apply_transformations(${lit(req.params.name)}) as result`
            );
            const transformData = transformResult.rows[0].result;

            res.json({ ...importData, transform: transformData });
        } catch (err) {
            next(err);
        }
    });

    // Get import log
    router.get('/:name/import-log', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM get_import_log(${lit(req.params.name)})`);
            res.json(result.rows);
        } catch (err) {
            next(err);
        }
    });

    // Delete an import (removes all records from that batch and the log entry)
    router.delete('/:name/import-log/:id', async (req, res, next) => {
        try {
            const result = await pool.query(
                `SELECT delete_import(${lit(parseInt(req.params.id))}) as result`
            );
            const data = result.rows[0].result;
            if (!data.success) return res.status(404).json(data);
            res.json(data);
        } catch (err) {
            next(err);
        }
    });

    // Apply transformations
    router.post('/:name/transform', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT apply_transformations(${lit(req.params.name)}) as result`);
            res.json(result.rows[0].result);
        } catch (err) {
            next(err);
        }
    });

    // Get all known field names for a source
    router.get('/:name/fields', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM get_source_fields(${lit(req.params.name)})`);
            res.json(result.rows);
        } catch (err) {
            next(err);
        }
    });

    // Generate output view
    router.post('/:name/view', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT generate_source_view(${lit(req.params.name)}) as result`);
            res.json(result.rows[0].result);
        } catch (err) {
            next(err);
        }
    });

    // Reprocess all records
    router.post('/:name/reprocess', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT reprocess_records(${lit(req.params.name)}) as result`);
            res.json(result.rows[0].result);
        } catch (err) {
            next(err);
        }
    });

    // Get statistics
    router.get('/:name/stats', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM get_source_stats(${lit(req.params.name)})`);
            res.json(result.rows[0]);
        } catch (err) {
            next(err);
        }
    });

    // Get view data (paginated, sortable)
    router.get('/:name/view-data', async (req, res, next) => {
        try {
            const { limit = 100, offset = 0, sort_col, sort_dir, filters } = req.query;
            let parsedFilters = null;
            if (filters) {
                try { parsedFilters = JSON.parse(filters); } catch { /* ignore bad JSON */ }
            }
            const result = await pool.query(
                `SELECT get_view_data(${lit(req.params.name)}, ${lit(parseInt(limit))}, ${lit(parseInt(offset))}, ${lit(sort_col || null)}, ${lit(sort_dir || 'asc')}, ${parsedFilters ? lit(parsedFilters) : 'NULL'}) as result`
            );
            res.json(result.rows[0].result);
        } catch (err) {
            next(err);
        }
    });

    // Pivot layouts
    router.get('/:name/layouts', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM list_pivot_layouts(${lit(req.params.name)})`);
            res.json(result.rows);
        } catch (err) { next(err); }
    });

    router.post('/:name/layouts', async (req, res, next) => {
        try {
            const { layout_name, config } = req.body;
            if (!layout_name || !config) return res.status(400).json({ error: 'layout_name and config required' });
            const result = await pool.query(
                `SELECT * FROM save_pivot_layout(${lit(req.params.name)}, ${lit(layout_name)}, ${lit(config)})`
            );
            res.json(result.rows[0]);
        } catch (err) { next(err); }
    });

    router.delete('/:name/layouts/:id', async (req, res, next) => {
        try {
            const result = await pool.query(`SELECT * FROM delete_pivot_layout(${lit(parseInt(req.params.id))})`);
            if (result.rows.length === 0) return res.status(404).json({ error: 'Layout not found' });
            res.json({ success: true });
        } catch (err) { next(err); }
    });

    return router;
};