import { Attribute, DB, Table } from "./db"
import { Aggregation, checkConstraint, Constraint, Datatype, Modifier, uniqueConstraint } from "./dbStructure"
import { Query, QueryBuilder, selectQuery } from "./query"
import { allModifierInput, primaryData, serializeReturn } from "./types"

export class Handler {
    async syncDB(db: DB, handler: Handler, deleteInDB: boolean = false) {
        console.log("start sync");

        let gd = new QueryBuilder();
        gd.addCode(`SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE where CONSTRAINT_SCHEMA = `);
        gd.addInjection(db.name);
        gd.addCode(` or TABLE_SCHEMA = `);
        gd.addInjection(db.name);
        gd.addCode(`;select * from information_schema.table_constraints where CONSTRAINT_SCHEMA = `);
        gd.addInjection(db.name)
        gd.addCode(` or TABLE_SCHEMA = `);
        gd.addInjection(db.name);

        let [key, constraints] = await db.query(handler.builders.query(gd));


        let tableData = [];
        for (let i = 0; i < db.tables.length; i++) {
            const table = db.tables[i];
            try {
                const tableDataBuilder = new QueryBuilder();
                tableDataBuilder.addCode("DESCRIBE ");
                tableDataBuilder.addCode(table.serialize(handler));
                tableData[i] = Object.fromEntries((await db.query(handler.builders.query(tableDataBuilder))).map((d: any) => [d.Field, d]));
            } catch (_) {
                tableData[i] = null;
            }
        }

        const del = new QueryBuilder();
        const create = new QueryBuilder();

        for (let i = 0; i < constraints.length; i++) {
            const c = constraints[i];
            if (c.CONSTRAINT_TYPE == "CHECK") {
                del.appendEnding(handler.querys.removeCheck(handler, c.TABLE_NAME, c.CONSTRAINT_NAME));
            }
        }
        // TODO: delete old constraints/tables

        function freeForUpdate(a: Attribute) {
            for (let i = 0; i < key.length; i++) {
                const k = key[i];
                if (
                    k.REFERENCED_TABLE_NAME == a.table.dbLangTableName
                    && k.REFERENCED_TABLE_NAME == a.name
                ) {
                    del.appendEnding(handler.querys.removeForeignKey(handler, k.TABLE_NAME, k.CONSTRAINT_NAME));
                }
            }
        }

        //create tables
        for (let i = 0; i < db.tables.length; i++) {
            const table = db.tables[i];
            const tableD = tableData[i];
            let changePrimary = false;
            if (tableD == null) {
                create.appendEnding(handler.querys.create(handler, table));
                changePrimary = true;
            } else {
                let keys = Object.keys(table.dbLangTableAttributes);
                for (let j = 0; j < keys.length; j++) {
                    const a = table.dbLangTableAttributes[keys[j]];
                    const attrData = tableD[keys[j]];
                    if (attrData == null) {
                        create.appendEnding(handler.querys.addColumn(handler, a));
                        changePrimary = true;
                    } else if (
                        !handler.builders.compareDatatypes(handler, a.type, attrData.Type) ||
                        a.ops.default != attrData.Default ||
                        (!!a.ops.notNull || !!a.ops.autoIncrement || !!a.ops.primaryKey) != (attrData.Null == "NO") ||
                        (!!a.ops.autoIncrement) != (attrData.Extra == "auto_increment")
                    ) {
                        console.log(!handler.builders.compareDatatypes(handler, a.type, attrData.Type), "|",
                            a.ops.default, attrData.Default, "|",
                            (!!a.ops.notNull || !!a.ops.autoIncrement || !!a.ops.primaryKey), (attrData.Null == "NO"), "|",
                            (!!a.ops.autoIncrement), (attrData.Extra == "auto_increment"));
                        freeForUpdate(a);
                        create.appendEnding(handler.querys.changeColumn(handler, a));
                    }
                    if (attrData == null) {
                        changePrimary = true;
                    } else {
                        if ((attrData.Key == "PRI") != (!!a.ops.primaryKey)) {
                            freeForUpdate(a);
                            changePrimary = true;
                        }
                    }
                }
            }
            if (changePrimary) {
                create.appendEnding(handler.querys.removePrimaryKey(handler, table));
                create.appendEnding(handler.querys.addPrimaryKey(handler, table));
            }
            for (let j = 0; j < table.dbLangConstrains.length; j++) {
                const c = table.dbLangConstrains[j];
                if (c instanceof checkConstraint) {
                    create.appendEnding(handler.querys.addCheck(handler, table, c));
                }
            }
            // TODO: unique
        }
        if (!create.isEmpty()) del.append(create);
        if (!del.isEmpty()) await db.query(handler.builders.query(del));
    }

    querys = {
        select: (handler: Handler, q: selectQuery): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.addCode("select ");
            builder.append(joinArg(", ")(handler, q.attr));
            builder.addCode(` from ${q.from == null ? 'DUAL' : q.from.serialize(handler)}`);
            if (q.whereD) {
                builder.addCode(" where ");
                builder.append(q.whereD.serialize(handler));
            }
            if (q.groupByD.length > 0) {
                builder.addCode(" group by ");
                builder.append(joinArg(",")(handler, q.groupByD));
                if (q.havingD) {
                    builder.addCode(" having ");
                    builder.append(q.havingD.serialize(handler));
                }
            }
            if (q.havingD) {
                builder.addCode(" limit ");
                builder.addInjection(q.limitD);
            }

            /*builder.setHandler((json)=>{
                return json;
            });*/

            return builder;
        },
        create: (handler: Handler, table: Table): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.addCode(`create table if not exists ${table.toString(handler)}(`);
            let keys = Object.keys(table.dbLangTableAttributes);
            for (let i = 0; i < keys.length; i++) {
                const a = table.dbLangTableAttributes[keys[i]];
                builder.addCode(a.serialize(handler) + " ");
                builder.append(a.serializeSettings(handler));
                if (i + 1 < keys.length) builder.addCode(", ");
            }
            builder.addCode(")");
            return builder;
        },
        addColumn: (handler: Handler, attr: Attribute): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.addCode(`alter table `);
            builder.addCode(attr.table.toString(handler));
            builder.addCode(` add if not exists `);
            builder.addCode(attr.serialize(handler) + " ");
            builder.append(attr.serializeSettings(handler));
            return builder;
        },
        changeColumn: (handler: Handler, attr: Attribute): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.addCode(`alter table `);
            builder.addCode(attr.table.toString(handler));
            builder.addCode(` change `);
            builder.addCode(attr.serialize(handler) + " ");
            builder.addCode(attr.serialize(handler) + " ");
            builder.append(attr.serializeSettings(handler));
            return builder;
        },
        addForeignKey: (handler: Handler, table: Table) => {
            const builder = new QueryBuilder();

            return builder;
        },
        removeForeignKey: (handler: Handler, tablenName: string, name: string) => {
            const builder = new QueryBuilder();
            builder.addCode("ALTER TABLE ");
            builder.addCode(handler.builders.escapeID(tablenName));
            builder.addCode(" DROP FOREIGN KEY IF EXISTS ");
            builder.addCode(handler.builders.escapeID(name));
            builder.addCode(";ALTER TABLE ");
            builder.addCode(handler.builders.escapeID(tablenName));
            builder.addCode(" DROP INDEX IF EXISTS ");
            builder.addCode(handler.builders.escapeID(name));

            return builder;
        },
        addPrimaryKey: (handler: Handler, table: Table) => {
            const qb = new QueryBuilder();
            qb.addCode("ALTER TABLE ");
            qb.addCode(table.serialize(handler));
            qb.addCode(" add PRIMARY KEY if not exists (");
            qb.addCodeCommaSeperated(
                Object.entries(table.dbLangTableAttributes)
                    .filter(([n, attr]) => !!attr.ops.primaryKey)
                    .map(([n, attr]) => handler.builders.escapeID(n))
            );
            qb.addCode(")");
            return qb;
        },
        removePrimaryKey: (handler: Handler, table: Table) => {
            const qb = new QueryBuilder();
            qb.addCode("ALTER TABLE ");
            qb.addCode(table.serialize(handler));
            qb.addCode(" DROP INDEX IF EXISTS `PRIMARY`");
            return qb;
        },
        removeCheck: (handler: Handler, table: string, name: string) => {
            const qb = new QueryBuilder();
            qb.addCode("ALTER TABLE ");
            qb.addCode(handler.builders.escapeID(table));
            qb.addCode(" DROP CONSTRAINT IF EXISTS ");
            qb.addCode(handler.builders.escapeID(name));
            return qb;
        },
        addCheck: (handler: Handler, table: Table, c: checkConstraint) => {
            const qb = new QueryBuilder();
            qb.addCode(`ALTER TABLE `);
            qb.addCode(table.serialize(handler));
            qb.addCode(` ADD CONSTRAINT `);
            qb.addCode(handler.builders.escapeID(c.name));
            qb.addCode(` CHECK (`);
            qb.append(c.checkQuery.serialize(handler));
            qb.addCode(")");
            return qb;
        },
        removeUnique: (handler: Handler, table: string, name: string) => {
            const qb = new QueryBuilder();
            qb.addCode("ALTER TABLE ");
            qb.addCode(handler.builders.escapeID(table));
            qb.addCode(" DROP INDEX IF EXISTS ");
            qb.addCode(handler.builders.escapeID(name));
            return qb;
        },
        addUnique: (handler: Handler, table: Table, u: uniqueConstraint) => {
            const qb = new QueryBuilder();
            qb.addCode("ALTER TABLE ");
            qb.addCode(table.serialize(handler));
            qb.addCode(" ADD CONSTRAINT ");
            qb.addCode(handler.builders.escapeID(u.name));
            qb.addCode(" UNIQUE (");
            qb.addCodeCommaSeperated(u.attrs.map(a => a.serialize(handler)));
            qb.addCode(")");
            return qb;
        },
        /*// add constraints
        appPrimaryKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        appForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        addUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        addChecks: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        //should drop all keys to be able to recreate them
        dropPrimaryKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        dropForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        dropUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        dropChecks: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        // check constraints
        listPrimaryKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        listForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        listUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
        listChecks: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),*/
    }

    builders = {
        query: (qb: QueryBuilder): Query => {
            let args: primaryData[] = [];
            let sql = "";
            for (let i = 0; i < qb.list.length; i++) {
                const [inject, data] = qb.list[i];
                if (inject) {
                    sql += "?";
                    args.push(data);
                } else {
                    sql += data;
                }
            }
            return new Query([sql, args]);
        },

        attributeSettings: (handler: Handler, a: Attribute): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.append(a.type.serialize(handler));
            if (a.ops.autoIncrement) {
                builder.addCode(" auto_increment");
            }
            if (a.ops.default != null) {
                if (a.ops.autoIncrement || a.ops.primaryKey || a.ops.notNull)
                    throw new Error(`Can not set default when autoIncrement, primaryKey or notNull ist set on Attribute: ${a.toStringFunc(handler)}`);
                builder.addCode(" default ");
                builder.addInjection(a.ops.default);
            }
            if (a.ops.notNull != null) {
                if (!a.ops.autoIncrement && !a.ops.primaryKey && a.ops.default == null) {
                    builder.addCode(" not null");
                } else builder.addCode(" null");
            } else builder.addCode(" null");
            return builder;
        },
        escapeID: (key: string): string => {
            if (!key || key === "" || key.includes('\u0000')) throw new Error("Can not escape empty key or with null unicode!");
            if (key.match(/^`.+`$/g)) return key;
            return `\`${key.replace(/`/g, '``')}\``;
        },
        compareDatatypes: (handler: Handler, attr: Datatype, curr: String) => {
            let qb = attr.serialize(handler);
            let sql = "";
            for (let i = 0; i < qb.list.length; i++) {
                const [inject, data] = qb.list[i];
                sql += data;
            }

            return curr.split(" ").join("").startsWith(sql.split(" ").join(""));
        },
    }


    aggregations = {
        count: (handler: Handler, a: Attribute): QueryBuilder => new QueryBuilder([{ data: "count(" + a.toString(handler) + ")" }]),
        sum: (handler: Handler, a: Attribute): QueryBuilder => new QueryBuilder([{ data: "sum(" + a.toString(handler) + ")" }]),
        avg: (handler: Handler, a: Attribute): QueryBuilder => new QueryBuilder([{ data: "avg(" + a.toString(handler) + ")" }]),
        min: (handler: Handler, a: Attribute): QueryBuilder => new QueryBuilder([{ data: "min(" + a.toString(handler) + ")" }]),
        max: (handler: Handler, a: Attribute): QueryBuilder => new QueryBuilder([{ data: "max(" + a.toString(handler) + ")" }]),
    }

    modifiers = {
        and: joinArg("and"),
        or: joinArg("or"),
        le: joinArg("<"),
        leq: joinArg("<="),
        eq: joinArg("="),
        geq: joinArg(">="),
        ge: joinArg(">"),
        plus: joinArg("+"),
        minus: joinArg("-"),
        not: (handler: Handler, a: allModifierInput[]): QueryBuilder => {
            let e = a[0];
            if (e instanceof Attribute) return new QueryBuilder([{ data: "not (" + e.toString(handler) + ")" }])
            if (e instanceof Modifier || e instanceof selectQuery || e instanceof Aggregation) {
                const builder = new QueryBuilder();
                builder.addCode("not (");
                builder.append(e.serialize(handler));
                builder.addCode(")");
                return builder;
            }
            return new QueryBuilder([
                { data: "not(" },
                { inject: true, data: e },
                { data: ")" }
            ])
        }
    }
    datatypes = {
        char: dataTypeSingleNum("char"),
        varchar: dataTypeSingleNum("varchar"),
        binary: dataTypeSingleNum("binary"),
        varbinary: dataTypeSingleNum("varbinary"),

        tinyblob: dataTypeNoArg("tinyblob"),
        blob: dataTypeNoArg("blob"),
        mediumblob: dataTypeNoArg("mediumblob"),
        longblob: dataTypeNoArg("longblob"),
        tinytext: dataTypeNoArg("tinytext"),
        text: dataTypeNoArg("text"),
        mediumtext: dataTypeNoArg("mediumtext"),
        longtext: dataTypeNoArg("longtext"),

        enum: (a: primaryData[]): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.addCode("enum(");
            builder.addInjectionCommaSeperated(a);
            builder.addCode(")");
            return builder;
        },
        set: (a: primaryData[]): QueryBuilder => {
            const builder = new QueryBuilder();
            builder.addCode("set(");
            builder.addInjectionCommaSeperated(a);
            builder.addCode(")");
            return builder;
        },
        bool: dataTypeNoArg("bool"),
        bit: dataTypeNoArg("bit"),
        tinyint: dataTypeNoArg("tinyint"),
        smallint: dataTypeNoArg("smallint"),
        mediumint: dataTypeNoArg("mediumint"),
        int: dataTypeNoArg("int"),
        bigint: dataTypeNoArg("bigint"),

        float: dataTypeDblNum("float"),
        double: dataTypeDblNum("double"),
        decimal: dataTypeDblNum("decimal"),

        date: dataTypeNoArg("date"),
        datetime: dataTypeNoArg("datatime"),
        timestamp: dataTypeNoArg("timestamp"),
        time: dataTypeNoArg("time"),
        year: dataTypeNoArg("year"),
    }

};

function dataTypeNoArg(type: string) {
    return (a: primaryData[]): QueryBuilder => {
        return new QueryBuilder([{
            inject: false,
            data: type
        }]);
    }
}
function dataTypeSingleNum(type: string) {
    return (a: primaryData[]): QueryBuilder => {
        return new QueryBuilder([
            { data: type + "(" },
            { inject: true, data: a[0] },
            { data: ")" }
        ]);
    }
}
function dataTypeDblNum(type: string) {
    return (a: primaryData[]): QueryBuilder => {
        return new QueryBuilder([
            { data: type + "(" },
            { inject: true, data: a[0] },
            { data: ", " },
            { inject: true, data: a[1] },
            { data: ")" }
        ]);
    }
}


function joinArg(type: string) {
    return (handler: Handler, a: (allModifierInput)[]): QueryBuilder => {
        const builder = new QueryBuilder();
        for (let i = 0; i < a.length; i++) {
            const d = a[i];
            if (d instanceof Attribute) builder.addCode(d.toString(handler));
            else if (d instanceof Modifier || d instanceof selectQuery || d instanceof Aggregation) {
                builder.addCode("(");
                builder.append(d.serialize(handler));
                builder.addCode(")");
            } else {
                builder.addInjection(d);
            }
            if (i + 1 < a.length) builder.addCode(" " + type + " ");
        }
        return builder;
    }
}