"use client";

import { useId, useMemo, useState } from "react";
import { createPortal } from "react-dom";
import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
import { Loader2, Plus, Trash2 } from "lucide-react";

import { Button } from "@/components/ui/button";
import { ResponsiveSheet } from "@/components/ui/responsive-sheet";
import { Label } from "@/components/ui/label";
import { Badge } from "@/components/ui/badge";
import {
  Select,
  SelectContent,
  SelectItem,
  SelectTrigger,
  SelectValue,
} from "@/components/ui/select";
import { Textarea } from "@/components/ui/textarea";
import { useFormatters, useTranslations } from "@/lib/i18n/context";
import { useRovingRadioGroup } from "@/hooks/use-roving-radio-group";
import type {
  MedicationSideEffectCategory,
  MedicationSideEffectEntry,
} from "@/generated/prisma/client";
import {
  SIDE_EFFECT_CATEGORY_ORDER,
  SIDE_EFFECT_SEVERITY_LADDER,
  categoryForEntry,
  entriesByCategory,
  severityLikertLabel,
} from "@/lib/medications/side-effects/taxonomy";
import { MedicationDetailSection } from "@/components/medications/medication-detail-section";

/**
 * v1.4.25 W19d — GLP-1 side-effect section for the medication detail
 * page. Sits below the drug-level chart and above the intake history
 * timeline. Mounted only for `treatmentClass === "GLP1"` rows.
 *
 * UX shape:
 *   - Section header + "Log side effect" CTA opens a modal dialog.
 *   - Inside the dialog: category picker → entry chip-picker (filtered
 *     by category) → 5-Likert severity ladder → optional notes.
 *   - Below the header: timeline of the last 30 days, newest first,
 *     each row showing category badge + entry label + severity chip +
 *     timestamp + delete button + collapsed notes.
 *
 * v1.4.25 W21 Fix-N — wraps the shared `<MedicationDetailSection>` so
 * the three sibling sections share one chrome contract, and swaps the
 * native `<select>` for the shadcn-radix `<Select>` so the picker
 * matches the rest of the form library (focus rings, keyboard nav,
 * theme tokens).
 *
 * Component-tests cover: empty state, category → entry filtering,
 * submit-and-refetch flow, severity-label translation lookup.
 */

interface SideEffectRow {
  id: string;
  category: MedicationSideEffectCategory;
  entry: MedicationSideEffectEntry;
  severity: number;
  occurredAt: string;
  notes: string | null;
  createdAt: string;
}

interface SideEffectsSectionProps {
  medicationId: string;
}

const NOTES_MAX = 280;

function categoryI18nKey(category: MedicationSideEffectCategory): string {
  // GI → gi, METABOLIC → metabolic, INJECTION_SITE → injectionSite,
  // COGNITIVE → cognitive, GLP1_SPECIFIC → glp1Specific.
  switch (category) {
    case "GI":
      return "gi";
    case "METABOLIC":
      return "metabolic";
    case "INJECTION_SITE":
      return "injectionSite";
    case "COGNITIVE":
      return "cognitive";
    case "GLP1_SPECIFIC":
      return "glp1Specific";
  }
}

function entryI18nKey(entry: MedicationSideEffectEntry): string {
  // SCREAMING_SNAKE → camelCase.
  return entry
    .toLowerCase()
    .replace(/_([a-z])/g, (_, c: string) => c.toUpperCase());
}

export function SideEffectsSection({ medicationId }: SideEffectsSectionProps) {
  const { t } = useTranslations();
  const fmt = useFormatters();
  const queryClient = useQueryClient();

  const [open, setOpen] = useState(false);
  const [category, setCategory] = useState<MedicationSideEffectCategory>("GI");
  const [entry, setEntry] = useState<MedicationSideEffectEntry | null>(null);
  const [severity, setSeverity] = useState<1 | 2 | 3 | 4 | 5 | null>(null);
  const [notes, setNotes] = useState<string>("");
  const [formError, setFormError] = useState<string | null>(null);
  // v1.4.27 R4 RC2 — sticky-pin the Save / Cancel row by portalling it
  // into the `<ResponsiveSheet>` footer slot. The submit button keeps
  // its `<form>` association via the HTML `form` attribute.
  const [footerEl, setFooterEl] = useState<HTMLDivElement | null>(null);
  const formId = useId();

  const listKey = [
    "medications",
    medicationId,
    "side-effects",
    "list",
  ] as const;

  const { data, isLoading } = useQuery({
    queryKey: listKey,
    queryFn: async () => {
      // Last 30 days, newest-first.
      const to = new Date();
      const from = new Date(to.getTime() - 30 * 24 * 60 * 60 * 1000);
      const url = `/api/medications/${medicationId}/side-effects?from=${encodeURIComponent(from.toISOString())}&to=${encodeURIComponent(to.toISOString())}&limit=100`;
      const res = await fetch(url);
      if (!res.ok) return { items: [] as SideEffectRow[], meta: { total: 0 } };
      const json = (await res.json()) as {
        data: { items: SideEffectRow[]; meta: { total: number } };
      };
      return json.data;
    },
    staleTime: 30 * 1000,
  });

  const createMutation = useMutation({
    mutationFn: async (payload: {
      entry: MedicationSideEffectEntry;
      severity: number;
      notes: string | null;
    }) => {
      // v1.4.25 W21 Fix-N (code-M6) — drop client-side `category`
      // from the wire payload. The server derives it from the entry
      // via `categoryForEntry`. Backwards-compatible with older
      // clients during the cut window (route accepts both shapes).
      const res = await fetch(`/api/medications/${medicationId}/side-effects`, {
        method: "POST",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify(payload),
      });
      if (!res.ok) {
        const body = (await res.json().catch(() => ({}))) as {
          error?: string;
        };
        throw new Error(body.error ?? "Failed to log side effect");
      }
      return (await res.json()).data as SideEffectRow;
    },
    onSuccess: () => {
      void queryClient.invalidateQueries({ queryKey: listKey });
    },
  });

  const deleteMutation = useMutation({
    mutationFn: async (logId: string) => {
      const res = await fetch(
        `/api/medications/${medicationId}/side-effects/${logId}`,
        { method: "DELETE" },
      );
      if (!res.ok) throw new Error("Failed to delete entry");
      return true;
    },
    onSuccess: () => {
      void queryClient.invalidateQueries({ queryKey: listKey });
    },
  });

  const items = data?.items ?? [];

  const filteredEntries = useMemo(
    () => entriesByCategory(category),
    [category],
  );

  const { getRadioProps: getEntryRadioProps } = useRovingRadioGroup({
    count: filteredEntries.length,
    selectedIndex: entry ? filteredEntries.indexOf(entry) : -1,
    onSelect: (index) => setEntry(filteredEntries[index]!),
  });
  const { getRadioProps: getSeverityRadioProps } = useRovingRadioGroup({
    count: SIDE_EFFECT_SEVERITY_LADDER.length,
    selectedIndex: severity !== null ? severity - 1 : -1,
    onSelect: (index) => setSeverity((index + 1) as 1 | 2 | 3 | 4 | 5),
  });

  function resetForm() {
    setCategory("GI");
    setEntry(null);
    setSeverity(null);
    setNotes("");
    setFormError(null);
  }

  function handleSubmit(e: React.FormEvent<HTMLFormElement>) {
    e.preventDefault();
    setFormError(null);
    if (!entry) {
      setFormError(t("medications.sideEffects.errorEntry"));
      return;
    }
    if (!severity) {
      setFormError(t("medications.sideEffects.errorSeverity"));
      return;
    }
    // Sanity-check the entry still belongs to the picked category;
    // the server derives the category authoritatively from `entry`.
    void categoryForEntry(entry);
    createMutation.mutate(
      {
        entry,
        severity,
        notes: notes.trim() ? notes.trim().slice(0, NOTES_MAX) : null,
      },
      {
        onSuccess: () => {
          resetForm();
          setOpen(false);
        },
        onError: (err) => {
          setFormError(err instanceof Error ? err.message : String(err));
        },
      },
    );
  }

  const headerExtras = (
    <>
      {items.length > 0 && (
        <span className="text-muted-foreground mr-2 font-normal">
          ({items.length})
        </span>
      )}
      <Button
        size="sm"
        variant="outline"
        onClick={() => {
          resetForm();
          setOpen(true);
        }}
      >
        <Plus className="h-3.5 w-3.5" />
        {t("medications.sideEffects.addCta")}
      </Button>
    </>
  );

  return (
    <MedicationDetailSection
      titleId="side-effects-heading"
      title={t("medications.sideEffects.section")}
      headerExtras={headerExtras}
    >
      {isLoading && (
        <div className="text-muted-foreground flex items-center gap-2">
          <Loader2 className="h-3.5 w-3.5 animate-spin motion-reduce:animate-none" />
          <span>{t("medications.sideEffects.loading")}</span>
        </div>
      )}

      {!isLoading && items.length === 0 && (
        <p className="text-muted-foreground py-1">
          {t("medications.sideEffects.emptyState")}
        </p>
      )}

      {!isLoading && items.length > 0 && (
        <div className="space-y-2">
          <p className="text-muted-foreground text-xs tracking-wide uppercase">
            {t("medications.sideEffects.recentTitle")}
          </p>
          <ul className="space-y-1.5">
            {items.map((row) => (
              <li
                key={row.id}
                className="bg-muted/30 flex items-start justify-between gap-2 rounded-md px-2.5 py-2"
              >
                <div className="min-w-0 flex-1 space-y-1">
                  {/* v1.4.28 FB-F2 — fixed-width date slot pinned to
                      the right of the row meta so the date stamp keeps
                      its column across rows. The category badge +
                      entry label + severity chip share the left-most
                      slot; the date claims a 4ch-wide right column. */}
                  <div className="flex items-start gap-2">
                    <div className="flex min-w-0 flex-1 flex-wrap items-center gap-1.5">
                      <Badge variant="outline" className="text-xs">
                        {t(
                          `medications.sideEffects.categories.${categoryI18nKey(row.category)}`,
                        )}
                      </Badge>
                      <span className="text-foreground truncate text-sm font-medium">
                        {t(
                          `medications.sideEffects.entries.${entryI18nKey(row.entry)}`,
                        )}
                      </span>
                      <Badge variant="secondary" className="text-xs">
                        {t(
                          `medications.sideEffects.severity.${severityLikertLabel(row.severity as 1 | 2 | 3 | 4 | 5)}`,
                        )}
                      </Badge>
                    </div>
                    <p
                      // D-H7 — narrowed from `w-[5.5rem]` (88 px) to
                      // `w-14` (56 px). The longest short-date variant
                      // ("15. Mai") fits inside 56 px with slack;
                      // recovering 32 px relieves the left slot's
                      // wrap rhythm at 320 px so the category badge +
                      // entry label + severity chip stop pushing the
                      // free-text notes off-screen.
                      className="text-muted-foreground w-14 shrink-0 text-right text-xs tabular-nums"
                      data-slot="side-effect-row-date"
                    >
                      {fmt.dateShort(new Date(row.occurredAt))}
                    </p>
                  </div>
                  {row.notes && (
                    <p
                      className="text-foreground/80 line-clamp-2 text-sm break-words"
                      data-slot="side-effect-row-notes"
                    >
                      {row.notes}
                    </p>
                  )}
                </div>
                <Button
                  variant="ghost"
                  size="icon"
                  className="text-muted-foreground hover:text-destructive size-11 shrink-0"
                  aria-label={t("medications.sideEffects.deleteCta")}
                  onClick={() => {
                    if (
                      typeof window === "undefined" ||
                      window.confirm(t("medications.sideEffects.deleteConfirm"))
                    ) {
                      deleteMutation.mutate(row.id);
                    }
                  }}
                  disabled={deleteMutation.isPending}
                >
                  <Trash2 className="h-3.5 w-3.5" />
                </Button>
              </li>
            ))}
          </ul>
        </div>
      )}

      <ResponsiveSheet
        open={open}
        onOpenChange={setOpen}
        title={t("medications.sideEffects.sheetTitle")}
        footer={<div ref={setFooterEl} className="flex w-full" />}
      >
        <form
          id={formId}
          onSubmit={handleSubmit}
          className="space-y-4"
          aria-label={t("medications.sideEffects.sheetTitle")}
        >
          <div className="space-y-1.5">
            <Label htmlFor="side-effect-category">
              {t("medications.sideEffects.categoryLabel")}
            </Label>
            <Select
              value={category}
              onValueChange={(next) => {
                setCategory(next as MedicationSideEffectCategory);
                // Reset entry — the previously-selected entry probably
                // doesn't belong to the new category.
                setEntry(null);
              }}
            >
              <SelectTrigger
                id="side-effect-category"
                className="w-full"
                data-slot="side-effect-category-trigger"
              >
                <SelectValue />
              </SelectTrigger>
              <SelectContent>
                {SIDE_EFFECT_CATEGORY_ORDER.map((c) => (
                  <SelectItem key={c} value={c}>
                    {t(
                      `medications.sideEffects.categories.${categoryI18nKey(c)}`,
                    )}
                  </SelectItem>
                ))}
              </SelectContent>
            </Select>
          </div>

          <div className="space-y-1.5">
            <Label>{t("medications.sideEffects.entryLabel")}</Label>
            <div
              className="flex flex-wrap gap-1.5"
              role="radiogroup"
              aria-label={t("medications.sideEffects.entryLabel")}
            >
              {filteredEntries.map((candidate, index) => {
                const selected = candidate === entry;
                return (
                  <button
                    type="button"
                    key={candidate}
                    role="radio"
                    aria-checked={selected}
                    onClick={() => setEntry(candidate)}
                    {...getEntryRadioProps(index)}
                    className={`rounded-full border px-2.5 py-1 text-xs transition-colors ${
                      selected
                        ? "border-primary bg-primary text-primary-foreground"
                        : "border-border bg-background text-foreground hover:bg-muted"
                    }`}
                  >
                    {t(
                      `medications.sideEffects.entries.${entryI18nKey(candidate)}`,
                    )}
                  </button>
                );
              })}
            </div>
          </div>

          <div className="space-y-1.5">
            <Label>{t("medications.sideEffects.severityLabel")}</Label>
            <div
              className="flex flex-wrap gap-1.5"
              role="radiogroup"
              aria-label={t("medications.sideEffects.severityLabel")}
            >
              {SIDE_EFFECT_SEVERITY_LADDER.map((label, idx) => {
                const value = (idx + 1) as 1 | 2 | 3 | 4 | 5;
                const selected = severity === value;
                return (
                  <button
                    type="button"
                    key={label}
                    role="radio"
                    aria-checked={selected}
                    onClick={() => setSeverity(value)}
                    {...getSeverityRadioProps(idx)}
                    className={`min-w-[2.5rem] rounded-md border px-2.5 py-1.5 text-xs font-medium transition-colors ${
                      selected
                        ? "border-primary bg-primary text-primary-foreground"
                        : "border-border bg-background text-foreground hover:bg-muted"
                    }`}
                  >
                    <span aria-hidden className="block text-sm">
                      {value}
                    </span>
                    <span className="block text-[10px] opacity-80">
                      {t(`medications.sideEffects.severity.${label}`)}
                    </span>
                  </button>
                );
              })}
            </div>
          </div>

          <div className="space-y-1.5">
            <Label htmlFor="side-effect-notes">
              {t("medications.sideEffects.notesLabel")}
            </Label>
            <Textarea
              id="side-effect-notes"
              value={notes}
              onChange={(e) => setNotes(e.target.value.slice(0, NOTES_MAX))}
              placeholder={t("medications.sideEffects.notesPlaceholder")}
              rows={3}
              maxLength={NOTES_MAX}
              enterKeyHint="done"
              // Compact notes-row padding override; primitive's
              // px-3 py-2 is too tall inside the side-effect modal.
              className="px-2 py-1.5"
            />
            <p className="text-muted-foreground text-right text-[10px]">
              {notes.length} / {NOTES_MAX}
            </p>
          </div>

          {formError && (
            <p className="text-destructive text-sm" role="alert">
              {formError}
            </p>
          )}
        </form>
        {footerEl
          ? createPortal(
              <div className="flex w-full flex-col-reverse gap-2 sm:flex-row sm:justify-end">
                <Button
                  type="button"
                  variant="ghost"
                  onClick={() => setOpen(false)}
                >
                  {t("medications.sideEffects.cancelCta")}
                </Button>
                <Button
                  type="submit"
                  form={formId}
                  disabled={createMutation.isPending}
                >
                  {createMutation.isPending && (
                    <Loader2 className="h-3.5 w-3.5 animate-spin motion-reduce:animate-none" />
                  )}
                  {t("medications.sideEffects.submitCta")}
                </Button>
              </div>,
              footerEl,
            )
          : null}
      </ResponsiveSheet>
    </MedicationDetailSection>
  );
}