// app/notes/NotesList.tsx
// Client Component. Owns the notes UI state (filter, add-form, edit,
// optimistic CRUD). All server calls go through /api/notes/* JSON routes.

"use client";

import { useMemo, useState } from "react";
import type { YsterbaardNote } from "@/lib/types";

type Filter = "all" | "open" | "done";

interface Props {
  initialNotes: YsterbaardNote[];
}

export default function NotesList({ initialNotes }: Props) {
  const [notes, setNotes] = useState<YsterbaardNote[]>(initialNotes);
  const [filter, setFilter] = useState<Filter>("all");
  const [adding, setAdding] = useState(false);
  const [editingId, setEditingId] = useState<string | null>(null);
  const [error, setError] = useState<string | null>(null);

  // Sort: open first (created desc), then done (done_at desc).
  const sorted = useMemo(() => {
    const open = notes
      .filter((n) => !n.is_done)
      .slice()
      .sort((a, b) => (a.created < b.created ? 1 : -1));
    const done = notes
      .filter((n) => n.is_done)
      .slice()
      .sort((a, b) => {
        const ad = a.done_at ?? a.updated ?? a.created;
        const bd = b.done_at ?? b.updated ?? b.created;
        return ad < bd ? 1 : -1;
      });
    return [...open, ...done];
  }, [notes]);

  const filtered = useMemo(() => {
    if (filter === "open") return sorted.filter((n) => !n.is_done);
    if (filter === "done") return sorted.filter((n) => n.is_done);
    return sorted;
  }, [sorted, filter]);

  function refresh(updated: YsterbaardNote) {
    setNotes((prev) => prev.map((n) => (n.id === updated.id ? updated : n)));
  }

  async function toggleDone(n: YsterbaardNote) {
    const nextDone = !n.is_done;
    // Optimistic
    setNotes((prev) =>
      prev.map((x) =>
        x.id === n.id
          ? { ...x, is_done: nextDone, done_at: nextDone ? new Date().toISOString() : null }
          : x,
      ),
    );
    try {
      const res = await fetch(`/api/notes/${encodeURIComponent(n.id)}`, {
        method: "PATCH",
        headers: { "Content-Type": "application/json" },
        body: JSON.stringify({ is_done: nextDone }),
      });
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
      const updated = (await res.json()) as YsterbaardNote;
      refresh(updated);
    } catch (e) {
      setError(`Could not update note: ${e instanceof Error ? e.message : "unknown"}`);
      // Rollback
      setNotes((prev) =>
        prev.map((x) =>
          x.id === n.id
            ? { ...x, is_done: !nextDone, done_at: !nextDone ? new Date().toISOString() : null }
            : x,
        ),
      );
    }
  }

  async function deleteNote(n: YsterbaardNote) {
    if (!confirm(`Delete "${n.title}"?`)) return;
    const snapshot = notes;
    setNotes((prev) => prev.filter((x) => x.id !== n.id));
    try {
      const res = await fetch(`/api/notes/${encodeURIComponent(n.id)}`, { method: "DELETE" });
      if (!res.ok) throw new Error(`HTTP ${res.status}`);
    } catch (e) {
      setError(`Could not delete note: ${e instanceof Error ? e.message : "unknown"}`);
      setNotes(snapshot);
    }
  }

  async function createNote(payload: { title: string; content: string }) {
    const res = await fetch("/api/notes", {
      method: "POST",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const created = (await res.json()) as YsterbaardNote;
    setNotes((prev) => [created, ...prev]);
  }

  async function updateNote(id: string, payload: { title?: string; content?: string }) {
    const res = await fetch(`/api/notes/${encodeURIComponent(id)}`, {
      method: "PATCH",
      headers: { "Content-Type": "application/json" },
      body: JSON.stringify(payload),
    });
    if (!res.ok) throw new Error(`HTTP ${res.status}`);
    const updated = (await res.json()) as YsterbaardNote;
    refresh(updated);
  }

  return (
    <div className="container-x py-6 space-y-4">
      {error && (
        <div className="rounded-md border border-amber-300 bg-amber-50 text-amber-900 px-3 py-2 text-sm">
          {error}
          <button className="ml-2 underline" onClick={() => setError(null)}>
            dismiss
          </button>
        </div>
      )}

      <div className="flex items-center justify-between gap-3">
        <div className="inline-flex rounded-md border border-border bg-surface-warm p-0.5">
          {(["all", "open", "done"] as Filter[]).map((f) => (
            <button
              key={f}
              type="button"
              onClick={() => setFilter(f)}
              data-od-id={`notes-filter-${f}`}
              className={
                "px-3 py-1 text-xs font-semibold rounded " +
                (filter === f
                  ? "bg-surface text-fg"
                  : "text-muted hover:text-fg")
              }
            >
              {f === "all" ? "All" : f === "open" ? "Open" : "Done"}
            </button>
          ))}
        </div>
        {!adding && (
          <button
            type="button"
            onClick={() => setAdding(true)}
            data-od-id="notes-add"
            className="inline-flex items-center gap-1.5 rounded-md bg-accent text-accent-on px-3 py-1.5 text-sm font-semibold"
          >
            + Add note
          </button>
        )}
      </div>

      {adding && (
        <AddForm
          onCancel={() => setAdding(false)}
          onSubmit={async (payload) => {
            try {
              await createNote(payload);
              setAdding(false);
            } catch (e) {
              setError(`Could not create note: ${e instanceof Error ? e.message : "unknown"}`);
            }
          }}
        />
      )}

      {filtered.length === 0 ? (
        <EmptyState filter={filter} />
      ) : (
        <ul className="space-y-2">
          {filtered.map((n) =>
            editingId === n.id ? (
              <EditRow
                key={n.id}
                note={n}
                onCancel={() => setEditingId(null)}
                onSave={async (payload) => {
                  try {
                    await updateNote(n.id, payload);
                    setEditingId(null);
                  } catch (e) {
                    setError(`Could not save note: ${e instanceof Error ? e.message : "unknown"}`);
                  }
                }}
              />
            ) : (
              <Row
                key={n.id}
                note={n}
                onToggle={() => toggleDone(n)}
                onEdit={() => setEditingId(n.id)}
                onDelete={() => deleteNote(n)}
              />
            ),
          )}
        </ul>
      )}
    </div>
  );
}

function AddForm({
  onCancel,
  onSubmit,
}: {
  onCancel: () => void;
  onSubmit: (payload: { title: string; content: string }) => Promise<void>;
}) {
  const [title, setTitle] = useState("");
  const [content, setContent] = useState("");
  const [busy, setBusy] = useState(false);
  return (
    <div className="rounded-md border border-border bg-surface p-4 space-y-2">
      <input
        autoFocus
        type="text"
        placeholder="Note title"
        value={title}
        onChange={(e) => setTitle(e.target.value)}
        className="w-full rounded-md border border-border bg-surface-warm px-3 py-2 text-sm font-semibold text-fg placeholder:text-muted"
        data-od-id="notes-add-title"
      />
      <textarea
        placeholder="Details (optional)"
        value={content}
        onChange={(e) => setContent(e.target.value)}
        rows={3}
        className="w-full rounded-md border border-border bg-surface-warm px-3 py-2 text-sm text-fg placeholder:text-muted"
        data-od-id="notes-add-content"
      />
      <div className="flex justify-end gap-2">
        <button
          type="button"
          onClick={onCancel}
          disabled={busy}
          className="px-3 py-1.5 text-sm font-semibold text-muted hover:text-fg"
        >
          Cancel
        </button>
        <button
          type="button"
          disabled={busy || !title.trim()}
          onClick={async () => {
            setBusy(true);
            try {
              await onSubmit({ title: title.trim(), content: content.trim() });
            } finally {
              setBusy(false);
            }
          }}
          className="rounded-md bg-accent text-accent-on px-3 py-1.5 text-sm font-semibold disabled:opacity-50"
          data-od-id="notes-add-save"
        >
          Save
        </button>
      </div>
    </div>
  );
}

function Row({
  note,
  onToggle,
  onEdit,
  onDelete,
}: {
  note: YsterbaardNote;
  onToggle: () => void;
  onEdit: () => void;
  onDelete: () => void;
}) {
  return (
    <li
      className={
        "rounded-md border border-border bg-surface px-3 py-2.5 flex items-start gap-3 " +
        (note.is_done ? "opacity-70" : "")
      }
      data-od-id={`notes-row-${note.id}`}
    >
      <input
        type="checkbox"
        checked={note.is_done}
        onChange={onToggle}
        aria-label={note.is_done ? "Mark as not done" : "Mark as done"}
        className="mt-1 h-4 w-4 shrink-0 cursor-pointer"
        data-od-id={`notes-toggle-${note.id}`}
      />
      <div className="flex-1 min-w-0">
        <div
          className={
            "font-semibold text-fg break-words " +
            (note.is_done ? "line-through text-muted" : "")
          }
        >
          {note.title}
        </div>
        {note.content ? (
          <div
            className={
              "text-sm mt-0.5 break-words whitespace-pre-wrap " +
              (note.is_done ? "text-muted line-through" : "text-muted")
            }
          >
            {note.content}
          </div>
        ) : null}
      </div>
      <div className="flex shrink-0 items-center gap-1">
        <button
          type="button"
          onClick={onEdit}
          className="px-2 py-1 text-xs font-semibold text-muted hover:text-fg"
          data-od-id={`notes-edit-${note.id}`}
        >
          Edit
        </button>
        <button
          type="button"
          onClick={onDelete}
          className="px-2 py-1 text-xs font-semibold text-muted hover:text-red-700"
          data-od-id={`notes-delete-${note.id}`}
        >
          Delete
        </button>
      </div>
    </li>
  );
}

function EditRow({
  note,
  onCancel,
  onSave,
}: {
  note: YsterbaardNote;
  onCancel: () => void;
  onSave: (payload: { title: string; content: string }) => Promise<void>;
}) {
  const [title, setTitle] = useState(note.title);
  const [content, setContent] = useState(note.content ?? "");
  const [busy, setBusy] = useState(false);
  return (
    <li className="rounded-md border border-accent bg-surface p-4 space-y-2">
      <input
        autoFocus
        type="text"
        value={title}
        onChange={(e) => setTitle(e.target.value)}
        className="w-full rounded-md border border-border bg-surface-warm px-3 py-2 text-sm font-semibold text-fg"
        data-od-id={`notes-edit-title-${note.id}`}
      />
      <textarea
        value={content}
        onChange={(e) => setContent(e.target.value)}
        rows={3}
        className="w-full rounded-md border border-border bg-surface-warm px-3 py-2 text-sm text-fg"
        data-od-id={`notes-edit-content-${note.id}`}
      />
      <div className="flex justify-end gap-2">
        <button
          type="button"
          onClick={onCancel}
          disabled={busy}
          className="px-3 py-1.5 text-sm font-semibold text-muted hover:text-fg"
        >
          Cancel
        </button>
        <button
          type="button"
          disabled={busy || !title.trim()}
          onClick={async () => {
            setBusy(true);
            try {
              await onSave({ title: title.trim(), content: content.trim() });
            } finally {
              setBusy(false);
            }
          }}
          className="rounded-md bg-accent text-accent-on px-3 py-1.5 text-sm font-semibold disabled:opacity-50"
          data-od-id={`notes-edit-save-${note.id}`}
        >
          Save
        </button>
      </div>
    </li>
  );
}

function EmptyState({ filter }: { filter: Filter }) {
  const msg =
    filter === "open"
      ? "No open notes. Great work."
      : filter === "done"
        ? "No done notes yet."
        : "No notes yet. Click + Add note to get started.";
  return (
    <div className="rounded-md border border-dashed border-border bg-surface-warm px-4 py-8 text-center text-sm text-muted">
      {msg}
    </div>
  );
}