const db = require('../config/dbproc.js');
const Adapter = require('./dbadapter.js');

class CurrencyAdapter extends Adapter {
    constructor() {
        super();
    }

    async queryCurrencyList(req, callback) {
        var apires = this.getApiResultDefined();
        try {
            let limit = req.query.limit;
            let offset = req.query.offset;
            let keyword = req.query.keyword ?? '';

            let qryBase = "select _idx, name, currency, symbol, rate from tbl_currency ";
            qryBase += "where isdeleted=0 and (name like '%" + keyword + "%' or currency like '%" + keyword + "%') ";

            // If no pagination params, return all records directly
            if (!limit || !offset) {
                db.query(qryBase + "order by currency asc", [], function (err, result, fields) {
                    if (err) {
                        apires.meta['message'] = err.toString();
                        apires.meta['code'] = 500;
                        callback('err', apires);
                    } else {
                        apires.success = true;
                        apires.data = JSON.parse(JSON.stringify(result));
                        callback(null, apires);
                    }
                });
                return;
            }

            db.query(qryBase + "order by currency asc", [], function (err, result, fields) {
                if (err) {
                    apires.meta['message'] = err.toString();
                    apires.meta['code'] = 500;
                    callback('err', apires);
                } else {
                    if (result.length > 0) {
                        let pagination = result.length / limit;
                        if (!Number.isInteger(pagination)) {
                            pagination = (Math.floor(result.length / limit)) + 1;
                        }
                        apires.success = true;
                        apires.data.push({
                            "totalpage": pagination,
                            "totalrows": result.length
                        });
                        let qryPage = qryBase + "order by currency asc limit " + offset + ", " + limit;
                        db.query(qryPage, [], function (err2, result2, fields2) {
                            if (err2) {
                                apires.meta['message'] = err2.toString();
                                apires.meta['code'] = 500;
                                callback('err', apires);
                            } else {
                                apires.data.push({
                                    "results": JSON.parse(JSON.stringify(result2))
                                });
                                callback(null, apires);
                            }
                        });
                    } else {
                        apires.meta.code = 200;
                        apires.meta.message = "Record Not Found";
                        callback(null, apires);
                    }
                }
            });
        } catch (err) {
            apires.meta.code = 500;
            apires.meta.message = err.toString();
            callback('error', apires);
        }
    }

    async queryCurrencyDetail(req, callback) {
        var apires = this.getApiResultDefined();
        try {
            let id = req.params.id;
            let qry = "select _idx, name, currency, symbol, rate, isdeleted, iby, idt, uby, udt from tbl_currency where _idx='" + id + "' and isdeleted=0";
            db.query(qry, [], function (err, result, fields) {
                if (err) {
                    apires.meta['message'] = err.toString();
                    apires.meta['code'] = 500;
                    callback('err', apires);
                } else {
                    if (result.length > 0) {
                        apires.success = true;
                        apires.data.push({
                            "results": JSON.parse(JSON.stringify(result))
                        });
                        callback(null, apires);
                    } else {
                        apires.meta.code = 200;
                        apires.meta.message = "Record Not Found";
                        callback(null, apires);
                    }
                }
            });
        } catch (err) {
            apires.meta.code = 500;
            apires.meta.message = err.toString();
            callback('error', apires);
        }
    }

    async queryCurrencyHistory(req, callback) {
        var apires = this.getApiResultDefined();
        try {
            let id = req.params.id;
            // get currency_code first, then fetch log
            let qryCode = "select currency from tbl_currency where _idx='" + id + "'";
            db.query(qryCode, [], function (err, result, fields) {
                if (err) {
                    apires.meta['message'] = err.toString();
                    apires.meta['code'] = 500;
                    callback('err', apires);
                } else {
                    if (result.length === 0) {
                        apires.meta.code = 200;
                        apires.meta.message = "Record Not Found";
                        callback(null, apires);
                        return;
                    }
                    let currencyCode = result[0].currency;
                    let qryLog = "select _idx, currency_code, old_rate, new_rate, source, remark, iby, idt from tbl_currency_log where currency_code='" + currencyCode + "' order by idt desc";
                    db.query(qryLog, [], function (err2, result2, fields2) {
                        if (err2) {
                            apires.meta['message'] = err2.toString();
                            apires.meta['code'] = 500;
                            callback('err', apires);
                        } else {
                            apires.success = true;
                            apires.data.push({
                                "results": JSON.parse(JSON.stringify(result2))
                            });
                            callback(null, apires);
                        }
                    });
                }
            });
        } catch (err) {
            apires.meta.code = 500;
            apires.meta.message = err.toString();
            callback('error', apires);
        }
    }

    async queryCreateCurrency(req, callback) {
        var apires = this.getApiResultDefined();
        try {
            let name = req.body.name;
            let currency = req.body.currency;
            let symbol = req.body.symbol;
            let rate = req.body.rate;
            let nik = req.nik;

            let qry = "insert into tbl_currency set ";
            qry += "name='" + name + "',";
            qry += "currency='" + currency + "',";
            qry += "symbol='" + symbol + "',";
            qry += "rate='" + rate + "',";
            qry += "isdeleted=0,";
            qry += "iby='" + nik + "',idt=now()";

            db.query(qry, [], function (err, result, fields) {
                if (err) {
                    apires.meta['message'] = err.toString();
                    apires.meta['code'] = 500;
                    callback('err', apires);
                } else {
                    apires.success = true;
                    apires.meta.message = "Saved Success";
                    apires.data = JSON.parse(JSON.stringify(result));
                    callback(null, apires);
                }
            });
        } catch (err) {
            apires.meta.code = 500;
            apires.meta.message = err.toString();
            callback('error', apires);
        }
    }

    async queryUpdateCurrency(req, callback) {
        var apires = this.getApiResultDefined();
        try {
            let id = req.params.id;
            let name = req.body.name;
            let currency = req.body.currency;
            let symbol = req.body.symbol;
            let newRate = req.body.rate;
            let nik = req.nik;

            // fetch current rate to detect change
            let qryOld = "select rate, currency from tbl_currency where _idx='" + id + "' and isdeleted=0";
            db.query(qryOld, [], function (err, oldResult, fields) {
                if (err) {
                    apires.meta['message'] = err.toString();
                    apires.meta['code'] = 500;
                    callback('err', apires);
                    return;
                }
                if (oldResult.length === 0) {
                    apires.meta.code = 200;
                    apires.meta.message = "Record Not Found";
                    callback(null, apires);
                    return;
                }

                let oldRate = oldResult[0].rate;
                let currencyCode = oldResult[0].currency;
                let rateChanged = parseFloat(oldRate) !== parseFloat(newRate);

                let qryUpdate = "update tbl_currency set ";
                qryUpdate += "name='" + name + "',";
                qryUpdate += "currency='" + currency + "',";
                qryUpdate += "symbol='" + symbol + "',";
                qryUpdate += "rate='" + newRate + "',";
                qryUpdate += "uby='" + nik + "',udt=now() ";
                qryUpdate += "where _idx='" + id + "'";

                db.query(qryUpdate, [], function (err2, result2, fields2) {
                    if (err2) {
                        apires.meta['message'] = err2.toString();
                        apires.meta['code'] = 500;
                        callback('err', apires);
                        return;
                    }

                    if (!rateChanged) {
                        apires.success = true;
                        apires.meta.message = "Updated Success";
                        apires.data = JSON.parse(JSON.stringify(result2));
                        callback(null, apires);
                        return;
                    }

                    // log the rate change
                    let qryLog = "insert into tbl_currency_log set ";
                    qryLog += "currency_code='" + currencyCode + "',";
                    qryLog += "old_rate='" + oldRate + "',";
                    qryLog += "new_rate='" + newRate + "',";
                    qryLog += "source='manual',";
                    qryLog += "iby='" + nik + "',idt=now()";

                    db.query(qryLog, [], function (err3, result3, fields3) {
                        if (err3) {
                            apires.meta['message'] = err3.toString();
                            apires.meta['code'] = 500;
                            callback('err', apires);
                        } else {
                            apires.success = true;
                            apires.meta.message = "Updated Success";
                            apires.data = JSON.parse(JSON.stringify(result2));
                            callback(null, apires);
                        }
                    });
                });
            });
        } catch (err) {
            apires.meta.code = 500;
            apires.meta.message = err.toString();
            callback('error', apires);
        }
    }

    async queryDeleteCurrency(req, callback) {
        var apires = this.getApiResultDefined();
        try {
            let id = req.params.id;
            let nik = req.nik;

            let qry = "update tbl_currency set isdeleted=1,dby='" + nik + "',ddt=now() where _idx='" + id + "'";
            db.query(qry, [], function (err, result, fields) {
                if (err) {
                    apires.meta['message'] = err.toString();
                    apires.meta['code'] = 500;
                    callback('err', apires);
                } else {
                    apires.success = true;
                    apires.meta.message = "Deleted Success";
                    apires.data = JSON.parse(JSON.stringify(result));
                    callback(null, apires);
                }
            });
        } catch (err) {
            apires.meta.code = 500;
            apires.meta.message = err.toString();
            callback('error', apires);
        }
    }

    // fetch rates for two currency IDs — used for cross-currency conversion
    queryCurrencyRates(fromId, toId, callback) {
        var apires = this.getApiResultDefined();
        let qry = "select _idx, rate from tbl_currency where _idx in ('" + fromId + "','" + toId + "') and isdeleted=0";
        db.query(qry, [], function (err, result, fields) {
            if (err) {
                callback(err, null);
                return;
            }
            var rates = {};
            result.forEach(function (row) {
                rates[row._idx] = parseFloat(row.rate);
            });
            if (rates[fromId] === undefined || rates[toId] === undefined) {
                callback(new Error('Currency not found'), null);
                return;
            }
            callback(null, { from: rates[fromId], to: rates[toId] });
        });
    }

    // convert amount from one currency to another using USD as pivot
    convertAmount(amount, rateFrom, rateTo, callback) {
        if (!rateTo || rateTo === 0) {
            callback(new Error('Invalid target rate: rate cannot be zero'), null);
            return;
        }
        callback(null, parseFloat(amount) * (rateFrom / rateTo));
    }
}

module.exports = CurrencyAdapter;