import ConnectionMutable from "./ConnectionMutable.ts";
import {Type} from "../../db/types.ts";
import {Collection} from "../../../../lib/src/collection/Collection.ts";
import {MalformedSQLGrammarError} from "./Select.ts";

export interface ColumnDefinition {
    with_name: string,
    with_type: Type,
    type_size?: string | number,
    null: boolean,
    as_primary_key: boolean,
    with_default?: string,
    sql: (level: number) => string,
    check_expression?: string,
    check_no_inherit: boolean,
}

export class ColumnFluency implements ColumnDefinition {
    public with_name: string = ''
    public with_type: Type = Type.varchar
    public null: boolean = false
    public as_primary_key: boolean = false
    public with_default?: string
    public type_size?: string | number
    public check_expression?: string
    public check_no_inherit: boolean = false

    public clone() {
        const col = new ColumnFluency()
        col.with_name = this.with_name
        col.with_type = this.with_type
        col.null = this.null
        col.as_primary_key = this.as_primary_key
        col.with_default = this.with_default
        col.type_size = this.type_size
        col.check_expression = this.check_expression
        col.check_no_inherit = this.check_no_inherit
        return col
    }

    public name(name: string): this {
        this.with_name = name
        return this
    }

    public type(type: Type, size?: string | number): this {
        this.with_type = type
        if ( size ) this.type_size = size
        return this
    }

    public nullable() {
        this.null = true
        return this
    }

    public primary_key() {
        this.as_primary_key = true
        return this
    }

    public default(val: string) {
        this.with_default = val
    }

    public check(expression: string, inherit: boolean = true): this {
        this.check_expression = expression
        this.check_no_inherit = !inherit
        return this
    }

    public sql(level: number = 0): string {
        const indent = Array(level).fill(' ').join('')

        const parts = []
        if ( this.null ) parts.push('NULL')
        else parts.push('NOT NULL')
        if ( this.as_primary_key ) parts.push('PRIMARY KEY')
        if ( this.with_default ) parts.push(`DEFAULT ${this.with_default}`)
        if ( this.check_expression ) {
            parts.push(`CHECK (${this.check_expression})${this.check_no_inherit ? ' NO INHERIT' : ''}`)
        }

        return `${indent}${this.with_name}    ${this.with_type}${this.type_size ? '('+this.type_size+')' : ''}${parts.length > 0 ? ' '+parts.join(' ') : ''}`
    }
}

export type FluencyFunction = (col: ColumnFluency) => any

export class CreateTable<T> extends ConnectionMutable<T> {
    protected _name?: string
    protected _column_defs: Collection<ColumnDefinition> = new Collection<ColumnDefinition>()

    constructor(name?: string) {
        super()
        if ( name ) this._name = name
    }

    sql(level: number = 0): string {
        const indent = Array(level).fill(' ').join('')

        if ( !this._name ) {
            throw new MalformedSQLGrammarError(`Missing required table name for create statement.`)
        }

        const column_sql = this._column_defs.map(x => `${indent}${x.sql(level + 1)}`)

        return [
            `CREATE TABLE ${this._name} (`,
                column_sql.join(`,\n${indent}`),
            ')'
        ].filter(x => String(x).trim()).join(`\n${indent}`)
    }

    name(name: string): this {
        this._name = name
        return this
    }

    column(name_or_fluency_fn: string | FluencyFunction, type?: Type, type_size?: string | number): this {
        const col = new ColumnFluency()

        if ( typeof name_or_fluency_fn === 'string' ) {
            if ( !type ) throw new MalformedSQLGrammarError(`Missing type for column: ${name_or_fluency_fn}`)
            col.name(name_or_fluency_fn)
                .type(type, type_size)
        } else {
            name_or_fluency_fn(col)
        }

        this._column_defs.push(col)
        return this
    }
}