Blockchain.js

class Blockchain {
    constructor(chain){
        this.chain = chain
        this.difficulty = 4

        this.nodeUrl = nodeURL
        this.networkNodes = []
    }

    createGenesisBlock() {
        return new Block(0, "03/17/2021", "Lynn Hill is GOAT", '0', 100)
    }

    getLatestBlock() {
        return this.chain[this.chain.length - 1]
    }

    addBlock(data) {
        const newBlock = new Block(
            this.chain.length,
            Date.now(),
            data
        )
        newBlock.previousHash = this.getLatestBlock().hash
        newBlock.mineBlock(this.difficulty)
        this.chain.push(newBlock)
        return newBlock
    }

    isChainValid(chain) {
        if (!chain) {
            return null
        }
        
        for(let i = 1; i < chain.length; i++){
            const currentBlock = chain[i]
            const previousBlock = chain[i - 1]

            if(currentBlock.hash !== this.calculateHash(currentBlock)) {
                return false
            }

            if(currentBlock.previousHash !== previousBlock.hash) {
                return false
            }
        }

        return true
    }


    findAllGymBlocks(gym_id) {
        return this.chain.filter(block => block.data.gym_id === gym_id)
    }

    findAllMemberBlocks(user_member_number, gym_id) {
        return this.chain.filter(block => block.data.gym_id === gym_id && block.data.user_member_number === user_member_number)
    }
}