import { Action, Funscript } from "./types";
import { getSpeed, roundAction } from "./utils";

/**
 * Converts a JSON string into a funscript object, computes metadata, and performs cleanup
 * @param  {string} funscriptJson - JSON string to be converted into a funscript object
 * @returns Converted funscript object
 */
export const getFunscriptFromString = (funscriptJson: string): Funscript => {
    const script = JSON.parse(funscriptJson);
    return addFunscriptMetadata(script);
}
/**
 * Adds metadata (average speed and duration) to a funscript, as well as make sure that its actions are in the right order
 * @param  {Funscript} funscript - Funscript to be processed
 * @returns Processed funscript with metadata
 */
export const addFunscriptMetadata = (funscript: Funscript): Funscript => {
    const output: Funscript = {...funscript};

    output.actions = output.actions.sort((a: Action, b: Action) => a.at - b.at).map(roundAction);
    const duration = output.actions.slice(-1)[0].at;

    const averageSpeed = output.actions.reduce((acc, action, index) => {
        if(index === 0) return acc;
        const speed = getSpeed(output.actions[index - 1], output.actions[index]);
        return acc + speed;
    }, 0) / (output.actions.length - 1);

    output.metadata = {
        ...output.metadata,
        duration,
        average_speed: averageSpeed,
    }
    return output;
}

/**
 * Converts a funscript into a CSV blob suitable for upload to a Handy
 * @param  {string} funscript - Funscript to be converted
 * @returns Plaintext blob ready to be uploaded to a Handy
 */
export const convertFunscriptToCsv = (funscript: string): Blob => {
    const script = JSON.parse(funscript);
    const csv = script.actions.map((action: Action) => {
        const roundedAction = roundAction(action);
        return roundedAction.at + "," + roundedAction.pos;
    }).join("\n");
    const csvBlob = new Blob([csv], {
        type: "text/plain"
    });

    return csvBlob;
}