import { DS4 } from "../config";

/**
 * Provides default values for all arguments the `CheckFactory` expects.
 */
class DefaultCheckOptions implements DS4CheckFactoryOptions {
    readonly maxCritSuccess = 1;
    readonly minCritFailure = 20;
    readonly useSlayingDice = false;
    readonly rollMode: Const.DiceRollMode = "roll";

    mergeWith(other: Partial<DS4CheckFactoryOptions>): DS4CheckFactoryOptions {
        return { ...this, ...other };
    }
}

/**
 * Singleton reference for default value extraction.
 */
const defaultCheckOptions = new DefaultCheckOptions();

/**
 * Most basic class responsible for generating the chat formula and passing it to the chat as roll.
 */
class CheckFactory {
    constructor(
        private checkTargetValue: number,
        private gmModifier: number,
        passedOptions: Partial<DS4CheckFactoryOptions> = {},
    ) {
        this.checkOptions = defaultCheckOptions.mergeWith(passedOptions);
    }

    private checkOptions: DS4CheckFactoryOptions;

    async execute(): Promise<ChatMessage | unknown> {
        const rollCls = CONFIG.Dice.rolls[0];

        const innerFormula = ["ds", this.createTargetValueTerm(), this.createCritTerm()].filterJoin("");
        const formula = this.checkOptions.useSlayingDice ? `{${innerFormula}}x` : innerFormula;
        const roll = new rollCls(formula);

        const rollModeTemplate = this.checkOptions.rollMode;
        return roll.toMessage({}, { rollMode: rollModeTemplate, create: true });
    }

    // Term generators
    createTargetValueTerm(): string | null {
        if (this.checkTargetValue !== null) {
            return "v" + (this.checkTargetValue + this.gmModifier);
        } else {
            return null;
        }
    }

    createCritTerm(): string | null {
        const minCritRequired = this.checkOptions.minCritFailure !== defaultCheckOptions.minCritFailure;
        const maxCritRequired = this.checkOptions.maxCritSuccess !== defaultCheckOptions.maxCritSuccess;

        if (minCritRequired || maxCritRequired) {
            return "c" + (this.checkOptions.maxCritSuccess ?? "") + ":" + (this.checkOptions.minCritFailure ?? "");
        } else {
            return null;
        }
    }
}

/**
 * Asks the user for all unknown/necessary information and passes them on to perform a roll.
 * @param targetValue - The Check Target Number ("CTN")
 * @param options     - Options changing the behavior of the roll and message.
 */
export async function createCheckRoll(
    targetValue: number,
    options: Partial<DS4CheckFactoryOptions> = {},
): Promise<ChatMessage | unknown> {
    // Ask for additional required data;
    const gmModifierData = await askGmModifier(targetValue, options);

    const newTargetValue = gmModifierData.checkTargetValue ?? targetValue;
    const gmModifier = gmModifierData.gmModifier ?? 0;
    const newOptions: Partial<DS4CheckFactoryOptions> = {
        maxCritSuccess: gmModifierData.maxCritSuccess ?? options.maxCritSuccess ?? undefined,
        minCritFailure: gmModifierData.minCritFailure ?? options.minCritFailure ?? undefined,
        useSlayingDice: gmModifierData.useSlayingDice ?? options.useSlayingDice ?? undefined,
        rollMode: gmModifierData.rollMode ?? options.rollMode ?? undefined,
    };

    // Create Factory
    const cf = new CheckFactory(newTargetValue, gmModifier, newOptions);

    // Possibly additional processing

    // Execute roll
    return cf.execute();
}

/**
 * Responsible for rendering the modal interface asking for the modifier specified by GM and (currently) additional data.
 *
 * @notes
 * At the moment, this asks for more data than it will do after some iterations.
 *
 * @returns The data given by the user.
 */
async function askGmModifier(
    targetValue: number,
    options: Partial<DS4CheckFactoryOptions> = {},
    { template, title }: { template?: string; title?: string } = {},
): Promise<Partial<IntermediateGmModifierData>> {
    // Render model interface and return value
    const usedTemplate = template ?? "systems/ds4/templates/roll/roll-options.hbs";
    const usedTitle = title ?? game.i18n.localize("DS4.RollDialogDefaultTitle");
    const templateData = {
        cssClass: "roll-option",
        title: usedTitle,
        checkTargetValue: targetValue,
        maxCritSuccess: options.maxCritSuccess ?? defaultCheckOptions.maxCritSuccess,
        minCritFailure: options.minCritFailure ?? defaultCheckOptions.minCritFailure,
        rollMode: options.rollMode,
        config: DS4,
    };
    const renderedHtml = await renderTemplate(usedTemplate, templateData);

    const dialogPromise = new Promise<HTMLFormElement>((resolve) => {
        new Dialog(
            {
                title: usedTitle,
                content: renderedHtml,
                buttons: {
                    ok: {
                        icon: '<i class="fas fa-check"></i>',
                        label: game.i18n.localize("DS4.GenericOkButton"),
                        callback: (html) => {
                            if (!("jquery" in html)) {
                                throw new Error(
                                    game.i18n.format("DS4.ErrorUnexpectedHtmlType", {
                                        exType: "JQuery",
                                        realType: "HTMLElement",
                                    }),
                                );
                            } else {
                                const innerForm = html[0].querySelector("form");
                                if (!innerForm) {
                                    throw new Error(
                                        game.i18n.format("DS4.ErrorCouldNotFindHtmlElement", { htmlElement: "form" }),
                                    );
                                }
                                resolve(innerForm);
                            }
                        },
                    },
                    cancel: {
                        icon: '<i class="fas fa-times"></i>',
                        label: game.i18n.localize("DS4.GenericCancelButton"),
                    },
                },
                default: "ok",
            },
            { jQuery: true },
        ).render(true);
    });
    const dialogForm = await dialogPromise;
    return parseDialogFormData(dialogForm);
}

/**
 * Extracts Dialog data from the returned DOM element.
 * @param formData - The filed dialog
 */
function parseDialogFormData(formData: HTMLFormElement): Partial<IntermediateGmModifierData> {
    return {
        checkTargetValue: parseInt(formData["ctv"]?.value),
        gmModifier: parseInt(formData["gmmod"]?.value),
        maxCritSuccess: parseInt(formData["maxcoup"]?.value),
        minCritFailure: parseInt(formData["minfumble"]?.value),
        rollMode: formData["visibility"]?.value,
    };
}

/**
 * Contains data that needs retrieval from an interactive Dialog.
 */
interface GmModifierData {
    gmModifier: number;
    rollMode: Const.DiceRollMode;
}

/**
 * Contains *CURRENTLY* necessary Data for drafting a roll.
 *
 * @deprecated
 * Quite a lot of this information is requested due to a lack of automation:
 *  - maxCritSuccess
 *  - minCritFailure
 *  - useSlayingDice
 *  - checkTargetValue
 *
 * They will and should be removed once effects and data retrieval is in place.
 * If a "raw" roll dialog is necessary, create another pre-porcessing Dialog
 * class asking for the required information.
 * This interface should then be replaced with the `GmModifierData`.
 */
interface IntermediateGmModifierData extends GmModifierData {
    checkTargetValue: number;
    gmModifier: number;
    maxCritSuccess: number;
    minCritFailure: number;
    // TODO: In final version from system settings
    useSlayingDice: boolean;
    rollMode: Const.DiceRollMode;
}

/**
 * The minimum behavioural options that need to be passed to the factory.
 */
export interface DS4CheckFactoryOptions {
    maxCritSuccess: number;
    minCritFailure: number;
    useSlayingDice: boolean;
    rollMode: Const.DiceRollMode;
}