import {infer as inferUtil} from '../../util'
import {ValidationResult} from './types'

/** Attempt to infer the native type of a string value. */
function infer(fieldName: string, inputValue: unknown): ValidationResult {
    return {
        valid: true,
        castValue: typeof inputValue === 'string' ? inferUtil(inputValue) : inputValue,
    }
}

/**
 * Casts the input value to a boolean.
 * Note that this assumes the value may be boolish. The strings "true", "True",
 * "TRUE", and "1" evaluate to `true`, while "false", "False", "FALSE", and "0"
 * evaluate to `false`.
 * @param fieldName
 * @param inputValue
 */
function boolean(fieldName: string, inputValue: unknown): ValidationResult {
    let castValue = Boolean(inputValue)

    if ( ['true', 'True', 'TRUE', '1'].includes(String(inputValue)) ) {
        castValue = true
    }
    if ( ['false', 'False', 'FALSE', '0'].includes(String(inputValue)) ) {
        castValue = false
    }

    return {
        valid: true,
        castValue,
    }
}

/** Casts the input value to a string. */
function string(fieldName: string, inputValue: unknown): ValidationResult {
    return {
        valid: true,
        castValue: String(inputValue),
    }
}

/** Casts the input value to a number, if it is numerical. Fails otherwise. */
function numeric(fieldName: string, inputValue: unknown): ValidationResult {
    if ( !isNaN(parseFloat(String(inputValue))) ) {
        return {
            valid: true,
            castValue: parseFloat(String(inputValue)),
        }
    }

    return {
        valid: false,
        message: 'must be numeric',
    }
}

/** Casts the input value to an integer. Fails otherwise. */
function integer(fieldName: string, inputValue: unknown): ValidationResult {
    if ( !isNaN(parseInt(String(inputValue), 10)) ) {
        return {
            valid: true,
            castValue: parseInt(String(inputValue), 10),
        }
    }

    return {
        valid: false,
        message: 'must be an integer',
    }
}

export const Cast = {
    infer,
    boolean,
    string,
    numeric,
    integer,
}