import React, { useCallback, useEffect, useState } from "react";
import { uploadMediaFile } from "../../../services/api";
import { whatsappBlastsApi } from "../../../services/api/whatsappBlasts";
import { PanelShell, RadioGroup, Label, Field, HelperText, IS, focusIn, focusOut } from "../panels/PanelShell";
import { WhatsAppCtaEditor, normalizeCtasForSave, type WhatsAppCtaItem } from "../whatsapp/WhatsAppCtaEditor";

function toDatetimeLocalValue(d: Date) {
  const pad = (n: number) => String(n).padStart(2, "0");
  return `${d.getFullYear()}-${pad(d.getMonth() + 1)}-${pad(d.getDate())}T${pad(d.getHours())}:${pad(d.getMinutes())}`;
}

export function SendWhatsAppNotificationPanel({
  eventId,
  eventName,
  onClose,
  onSuccess,
}: {
  eventId: string;
  eventName?: string;
  onClose: () => void;
  onSuccess?: () => void;
}) {
  const [body, setBody] = useState("");
  const [mediaType, setMediaType] = useState<"none" | "image" | "video">("none");
  const [mediaUrl, setMediaUrl] = useState("");
  const [ctas, setCtas] = useState<WhatsAppCtaItem[]>([]);
  const [when, setWhen] = useState<"now" | "schedule">("now");
  const [scheduleLocal, setScheduleLocal] = useState("");
  const [eligible, setEligible] = useState<number | null>(null);
  const [eligibleError, setEligibleError] = useState("");
  const [uploading, setUploading] = useState(false);
  const [saving, setSaving] = useState(false);
  const [err, setErr] = useState("");

  const loadEligible = useCallback(async () => {
    setEligibleError("");
    const res = await whatsappBlastsApi.eligibleCount(eventId);
    if (res.error) {
      setEligible(null);
      setEligibleError(res.error);
      return;
    }
    setEligible(res.data?.count ?? 0);
  }, [eventId]);

  useEffect(() => {
    void loadEligible();
    const t = window.setInterval(() => void loadEligible(), 30_000);
    return () => window.clearInterval(t);
  }, [loadEligible]);

  const onPickMedia = async (file: File | null) => {
    if (!file) return;
    const mime = String(file.type || "").toLowerCase();
    const nextType = mime.startsWith("video/") ? "video" : mime.startsWith("image/") ? "image" : null;
    if (!nextType) {
      setErr("Attach an image or video file.");
      return;
    }
    setUploading(true);
    setErr("");
    try {
      const up = await uploadMediaFile(file, { eventId, module: "whatsapp/notifications" });
      if (!up.url) {
        setErr("Upload failed");
        return;
      }
      setMediaType(nextType);
      setMediaUrl(up.url);
    } catch (e) {
      setErr(e instanceof Error ? e.message : "Upload failed");
    } finally {
      setUploading(false);
    }
  };

  const submit = async () => {
    const text = body.trim();
    let ctasPayload: WhatsAppCtaItem[] = [];
    try {
      ctasPayload = normalizeCtasForSave(ctas);
    } catch (e) {
      setErr(e instanceof Error ? e.message : "Invalid buttons");
      return;
    }
    if (ctasPayload.length && !text) {
      setErr("Message text is required when buttons are set.");
      return;
    }
    if (!text && !mediaUrl) {
      setErr("Enter a message or attach media.");
      return;
    }
    let sendAt: string | undefined;
    if (when === "schedule") {
      if (!scheduleLocal) {
        setErr("Pick a date and time.");
        return;
      }
      const d = new Date(scheduleLocal);
      if (Number.isNaN(d.getTime())) {
        setErr("Invalid schedule time.");
        return;
      }
      sendAt = d.toISOString();
    }
    setSaving(true);
    setErr("");
    const res = await whatsappBlastsApi.create(eventId, {
      body: text,
      mediaType: mediaUrl ? mediaType : "none",
      mediaUrl: mediaUrl || "",
      ctas: ctasPayload,
      ...(sendAt ? { sendAt } : {}),
    });
    setSaving(false);
    if (res.error) {
      setErr(res.error);
      return;
    }
    onSuccess?.();
    onClose();
  };

  const eligibleLine =
    eligibleError
      ? eligibleError
      : eligible == null
        ? "Counting people in the 24-hour WhatsApp window…"
        : `${eligible} ${eligible === 1 ? "person" : "people"} on this event can receive this now (open WhatsApp chat, last 24 hours).`;

  return (
    <PanelShell
      onClose={onClose}
      title="Send WhatsApp notification"
      breadcrumb={eventName ? `Event Home · ${eventName}` : "Event Home · WhatsApp Notifications"}
      description="Sends the same message to everyone on this event with an open WhatsApp chat still inside Meta’s 24-hour window."
      completedCount={1}
      totalSections={1}
      ctaLabel={saving ? "Sending…" : when === "schedule" ? "Schedule" : "Send now"}
      ctaDisabled={saving || uploading}
      onCtaClick={() => void submit()}
      showProgress={false}
      panelWidth="min(560px, 100vw)"
    >
      <div style={{ padding: "16px 20px", display: "flex", flexDirection: "column", gap: 14 }}>
        <p style={{ margin: 0, fontSize: "var(--text-sm)", color: "var(--card-foreground)" }}>{eligibleLine}</p>

        <Field>
          <Label text="Message" />
          <textarea
            value={body}
            onChange={(e) => setBody(e.target.value)}
            onFocus={focusIn}
            onBlur={focusOut}
            rows={6}
            placeholder="Write the WhatsApp message…"
            style={{ ...IS, minHeight: 120, resize: "vertical" }}
          />
        </Field>

        <Field>
          <Label text="Image or video (optional)" />
          {mediaUrl ? (
            <div style={{ display: "flex", alignItems: "center", gap: 8, flexWrap: "wrap" }}>
              <a href={mediaUrl} target="_blank" rel="noreferrer" style={{ fontSize: "var(--text-sm)", color: "var(--primary)" }}>
                {mediaType === "video" ? "Video attached" : "Image attached"}
              </a>
              <button
                type="button"
                onClick={() => {
                  setMediaUrl("");
                  setMediaType("none");
                }}
                style={{
                  fontSize: "var(--text-xs)",
                  fontFamily: "var(--font-noto-sans)",
                  border: "1px solid var(--border)",
                  background: "var(--secondary)",
                  borderRadius: "var(--radius-button)",
                  padding: "4px 8px",
                  cursor: "pointer",
                }}
              >
                Remove
              </button>
            </div>
          ) : (
            <input
              type="file"
              accept="image/*,video/*"
              disabled={uploading}
              onChange={(e) => {
                const file = e.target.files?.[0] || null;
                e.target.value = "";
                void onPickMedia(file);
              }}
            />
          )}
          <HelperText text={uploading ? "Uploading…" : "Optional. Recipients outside the 24-hour window are skipped."} />
        </Field>

        <Field>
          <WhatsAppCtaEditor value={ctas} onChange={setCtas} />
        </Field>

        <Field>
          <Label text="When" />
          <RadioGroup
            name="wa-blast-when"
            value={when}
            onChange={(v) => setWhen(v === "schedule" ? "schedule" : "now")}
            options={[
              { label: "Send now", value: "now" },
              { label: "Schedule", value: "schedule" },
            ]}
          />
        </Field>

        {when === "schedule" ? (
          <Field>
            <Label text="Schedule for" required />
            <input
              type="datetime-local"
              value={scheduleLocal}
              min={toDatetimeLocalValue(new Date())}
              onChange={(e) => setScheduleLocal(e.target.value)}
              onFocus={focusIn}
              onBlur={focusOut}
              style={IS}
            />
          </Field>
        ) : null}

        {err ? (
          <p style={{ margin: 0, fontSize: "var(--text-sm)", color: "var(--destructive)" }}>{err}</p>
        ) : null}
      </div>
    </PanelShell>
  );
}