/**
 * A key-value store that persists data using local storage.
 */
export default class LocalStoreContext {
    private context: Map<string, string | number | boolean> = new Map()
    private contextNamespace: string

    constructor(contextName: string) {
        this.contextNamespace = contextName
        this.rehydrateContext()
    }

    /**
     * Set a value in local storage.
     * @param key The key to store the value under.
     * @param value The value to store.
     */
    public set(key: string, value: string | number | boolean, valueType: 'string'|'number'|'boolean'): void {
        this.context[key] = `${valueType}:${value}`
        this.persistContext()
    }

    public get(key: string): string | number | boolean {
        const pair = this.context[key]
        if (!pair) {
            console.warn(`Key ${key} not found in local storage`)
            this.clear()
            // location.reload()
        }
        const [type, value] = pair.split(':')
        switch (type) {
        case 'string':
            return value
        case 'number':
            return parseFloat(value)
        case 'boolean':
            return value === 'true'
        default:
            throw new Error(`Unknown type ${type}`)
        }
    }

    public remove(key: string): void {
        delete this.context[key]
        this.persistContext()
    }

    public length(): number {
        return Object.keys(this.context).length
    }

    public clear(): void {
        this.context = new Map()
        this.persistContext()
    }

    private rehydrateContext(): void {
        const lsCtx = window.localStorage.getItem(this.contextNamespace) || '{}'
        this.context = JSON.parse(lsCtx)
    }

    private persistContext(): void {
        window.localStorage.setItem(this.contextNamespace, JSON.stringify(this.context))
    }
}