import fs from "fs"
import path from "node:path"
import {FileHandle} from "fs/promises"
import {IFile} from "./types.js"
import {createHash} from "crypto"

export class File implements IFile {
    path: string
    name: string
    extension: string = ""
    fullPath: string // path + name + extension

    constructor(fullPath: string) {
        this.fullPath = fullPath
        const parts = fullPath.split(path.sep)
        const fileName = parts.pop()
        if (!fileName) {
            throw new Error("Unable to parse file name")
        }
        this.name = fileName
        if (fileName.split(".").length > 1) {
            this.name = fileName.split(".").slice(0, -1).join(".")
            this.extension = fileName.split(".").slice(-1).join("")
        }
        this.path = parts.join(path.sep)
    }

    async readData(): Promise<Buffer> {
        try {
            return await fs.promises.readFile(this.fullPath)
        } catch (err: any) {
            throw new Error(`Failed to read file content: ${err.message}`)
        }
    }

    async writeData(data: Buffer): Promise<void> {
        try {
            return await fs.promises.writeFile(this.fullPath, data)
        } catch (err: any) {
            throw new Error(`Failed to write file content: ${err.message}`)
        }
    }

    async getHandle(): Promise<FileHandle> {
        try {
            return await fs.promises.open(this.fullPath, "r")
        } catch (err: any) {
            throw new Error(`Failed to open file handle: ${err.message}`)
        }
    }

    async getDataHash(algo: string = "sha256"): Promise<string> {
        const hash = createHash(algo)
        const bufferSize = 64 * 1024
        const buffer = Buffer.allocUnsafe(bufferSize)
        const fileHandle = await this.getHandle()

        try {
            let position = 0
            while (true) {
                const {bytesRead} = await fileHandle.read(buffer, 0, bufferSize, position)
                if (bytesRead === 0) break

                hash.update(buffer.subarray(0, bytesRead))
                position += bytesRead
            }
        } finally {
            await fileHandle.close()
        }

        return hash.digest("hex")
    }
}