import {
    CreateJobParams,
    NotificationChannel,
} from "../NotificationJobs/NotificationJobs.Interface";
import { NotificationJobsAdapterMongoose } from "../NotificationJobs/NotificationJobs.Adapter.Mongoose";
import { PolicyResolver, ResolvedPolicy } from "./PolicyResolver";
import dayjs from "dayjs";
import utc from "dayjs/plugin/utc";

dayjs.extend(utc);

export interface CreateJobServiceParams {
    companyId: string;
    clientId: string;
    appointmentId: string;
    type: CreateJobParams["type"];
    scheduledAt?: Date;
    appointmentStart?: Date;
    payload?: CreateJobParams["payload"];
    reminderPayload?: CreateJobParams["payload"];
}

export class NotificationJobService {
    private jobAdapter: NotificationJobsAdapterMongoose;
    private policyResolver: PolicyResolver;

    constructor() {
        this.jobAdapter = new NotificationJobsAdapterMongoose();
        this.policyResolver = new PolicyResolver();
    }

    async createJob(params: CreateJobServiceParams): Promise<any[]> {
        const resolvedPolicy = await this.policyResolver.resolve(
            params.companyId,
            params.clientId
        );

        if (resolvedPolicy.channels.length === 0) {
            return [];
        }

        const now = new Date();
        const baseScheduledAt = params.scheduledAt || now;
        const adjustedScheduledAt = this.adjustForQuietHours(
            baseScheduledAt,
            resolvedPolicy
        );

        const jobs: any[] = [];
        for (const channel of resolvedPolicy.channels) {
            const job = await this.jobAdapter.create({
                companyId: params.companyId,
                appointmentId: params.appointmentId,
                clientId: params.clientId,
                channel,
                type: params.type,
                scheduledAt: adjustedScheduledAt,
                payload: params.payload,
            });
            jobs.push(job);
        }

        if (params.appointmentStart) {
            const enabledReminderRules = (resolvedPolicy.reminderRules || []).filter(
                (rule) => rule.enabled
            );

            for (const rule of enabledReminderRules) {
                const reminderScheduledAt = this.adjustForQuietHours(
                    dayjs(params.appointmentStart).subtract(rule.offset, "minute").toDate(),
                    resolvedPolicy
                );

                if (reminderScheduledAt < now || reminderScheduledAt >= params.appointmentStart) {
                    continue;
                }

                for (const channel of resolvedPolicy.channels) {
                    const job = await this.jobAdapter.create({
                        companyId: params.companyId,
                        appointmentId: params.appointmentId,
                        clientId: params.clientId,
                        channel,
                        type: "reminder",
                        scheduledAt: reminderScheduledAt,
                        payload: params.reminderPayload,
                    });
                    jobs.push(job);
                }
            }
        }

        return jobs;
    }

    async createImmediateJob(params: CreateJobServiceParams): Promise<any[]> {
        const resolvedPolicy = await this.policyResolver.resolve(
            params.companyId,
            params.clientId
        );

        if (resolvedPolicy.channels.length === 0) {
            return [];
        }

        const scheduledAt = params.scheduledAt || new Date();
        const jobs: any[] = [];

        for (const channel of resolvedPolicy.channels) {
            const job = await this.jobAdapter.create({
                companyId: params.companyId,
                appointmentId: params.appointmentId,
                clientId: params.clientId,
                channel,
                type: params.type,
                scheduledAt,
                payload: params.payload,
            });
            jobs.push(job);
        }

        return jobs;
    }

    async createMandatoryCreationJob(params: CreateJobServiceParams): Promise<any[]> {
        const payloadChannels = this.getPayloadChannels(params.payload);
        const channels = await this.policyResolver.resolveAvailableChannels(
            params.companyId,
            payloadChannels
        );

        if (channels.length === 0) {
            return [];
        }

        const scheduledAt = params.scheduledAt || new Date();
        const jobs: any[] = [];

        for (const channel of channels) {
            const job = await this.jobAdapter.create({
                companyId: params.companyId,
                appointmentId: params.appointmentId,
                clientId: params.clientId,
                channel,
                type: "creation",
                scheduledAt,
                payload: params.payload,
            });
            jobs.push(job);
        }

        return jobs;
    }

    async createReminderJobs(params: CreateJobServiceParams): Promise<any[]> {
        const resolvedPolicy = await this.policyResolver.resolve(
            params.companyId,
            params.clientId
        );

        if (!params.appointmentStart || resolvedPolicy.channels.length === 0) {
            return [];
        }

        const now = new Date();
        const jobs: any[] = [];
        const enabledReminderRules = (resolvedPolicy.reminderRules || []).filter(
            (rule) => rule.enabled
        );

        for (const rule of enabledReminderRules) {
            const reminderScheduledAt = this.adjustForQuietHours(
                dayjs(params.appointmentStart).subtract(rule.offset, "minute").toDate(),
                resolvedPolicy
            );

            if (reminderScheduledAt < now || reminderScheduledAt >= params.appointmentStart) {
                continue;
            }

            for (const channel of resolvedPolicy.channels) {
                const job = await this.jobAdapter.create({
                    companyId: params.companyId,
                    appointmentId: params.appointmentId,
                    clientId: params.clientId,
                    channel,
                    type: "reminder",
                    scheduledAt: reminderScheduledAt,
                    payload: params.reminderPayload,
                });
                jobs.push(job);
            }
        }

        return jobs;
    }

    /**
     * Cancel all pending jobs for an appointment.
     * Called when an appointment is deleted or rescheduled.
     */
    async cancelByAppointment(appointmentId: string): Promise<void> {
        return this.jobAdapter.cancelByAppointment(appointmentId);
    }

    private adjustForQuietHours(scheduledAt: Date, policy: ResolvedPolicy): Date {
        if (!policy.quietHours?.from || !policy.quietHours?.to) {
            return scheduledAt;
        }

        const scheduled = dayjs.utc(scheduledAt);
        const fromHour = parseInt(policy.quietHours.from.split(":")[0], 10);
        const fromMinute = parseInt(policy.quietHours.from.split(":")[1], 10);
        const toHour = parseInt(policy.quietHours.to.split(":")[0], 10);
        const toMinute = parseInt(policy.quietHours.to.split(":")[1], 10);

        const scheduledHour = scheduled.hour();
        const scheduledMinute = scheduled.minute();

        const isInsideQuietHours = this.isTimeInQuietHours(
            scheduledHour,
            scheduledMinute,
            fromHour,
            fromMinute,
            toHour,
            toMinute
        );

        if (isInsideQuietHours) {
            // Shift to quiet hours end
            let adjusted = scheduled.hour(toHour).minute(toMinute).second(0);
            // If quiet hours cross midnight, only the pre-midnight segment ends next day.
            if (toHour < fromHour && scheduledHour >= fromHour) {
                adjusted = adjusted.add(1, "day");
            }
            return adjusted.toDate();
        }

        return scheduledAt;
    }

    private getPayloadChannels(payload?: CreateJobParams["payload"]): NotificationChannel[] {
        const channels: NotificationChannel[] = [];

        if (payload?.email) {
            channels.push("email");
        }

        if (payload?.phoneNumber) {
            channels.push("whatsapp");
        }

        if (payload?.userId) {
            channels.push("system");
        }

        return channels;
    }

    private isTimeInQuietHours(
        hour: number,
        minute: number,
        fromHour: number,
        fromMinute: number,
        toHour: number,
        toMinute: number
    ): boolean {
        const currentMinutes = hour * 60 + minute;
        const fromMinutes = fromHour * 60 + fromMinute;
        const toMinutes = toHour * 60 + toMinute;

        if (fromMinutes < toMinutes) {
            // Quiet hours within same day (e.g. 01:00-06:00)
            return currentMinutes >= fromMinutes && currentMinutes < toMinutes;
        } else {
            // Quiet hours cross midnight (e.g. 22:00-07:00)
            return currentMinutes >= fromMinutes || currentMinutes < toMinutes;
        }
    }
}