import { useGlobalConfig } from '../use-global-config'

export const defaultNamespace = 'el'
const statePrefix = 'is-'

const _bem = (namespace: string, block: string, blockSuffix: string, element: string, modifier: string) => {
    let cls = `${namespace}-${block}`
    if (blockSuffix) {
        cls += `-${blockSuffix}`
    }
    if (element) {
        cls += `__${element}`
    }
    if (modifier) {
        cls += `--${modifier}`
    }
    return cls
}

export const useNamespace = (block: string) => {
    const namespace = useGlobalConfig('namespace', defaultNamespace)
    const b = (blockSuffix = '') => _bem(namespace.value, block, blockSuffix, '', '')
    const e = (element?: string) => (element ? _bem(namespace.value, block, '', element, '') : '')
    const m = (modifier?: string) => (modifier ? _bem(namespace.value, block, '', '', modifier) : '')
    const be = (blockSuffix?: string, element?: string) => (blockSuffix && element ? _bem(namespace.value, block, blockSuffix, element, '') : '')
    const em = (element?: string, modifier?: string) => (element && modifier ? _bem(namespace.value, block, '', element, modifier) : '')
    const bm = (blockSuffix?: string, modifier?: string) => (blockSuffix && modifier ? _bem(namespace.value, block, blockSuffix, '', modifier) : '')
    const bem = (blockSuffix?: string, element?: string, modifier?: string) => (blockSuffix && element && modifier ? _bem(namespace.value, block, blockSuffix, element, modifier) : '')
    const is: {
        (name: string, state: boolean | undefined): string
        (name: string): string
    } = (name: string, ...args: [boolean | undefined] | []) => {
        const state = args.length >= 1 ? args[0]! : true
        return name && state ? `${statePrefix}${name}` : ''
    }

    // for css var
    // --el-xxx: value;
    const cssVar = (object: Record<string, string>) => {
        const styles: Record<string, string> = {}
        for (const key in object) {
            if (object[key]) {
                styles[`--${namespace.value}-${key}`] = object[key]
            }
        }
        return styles
    }
    // with block
    const cssVarBlock = (object: Record<string, string>) => {
        const styles: Record<string, string> = {}
        for (const key in object) {
            if (object[key]) {
                styles[`--${namespace.value}-${block}-${key}`] = object[key]
            }
        }
        return styles
    }

    const cssVarName = (name: string) => `--${namespace.value}-${name}`
    const cssVarBlockName = (name: string) => `--${namespace.value}-${block}-${name}`

    return {
        namespace,
        b,
        e,
        m,
        be,
        em,
        bm,
        bem,
        is,
        // css
        cssVar,
        cssVarName,
        cssVarBlock,
        cssVarBlockName,
    }
}

export type UseNamespaceReturn = ReturnType<typeof useNamespace>