import { useState } from "react";
import { Link } from "react-router";
import { useSWRConfig } from "swr";
import { Menu, MenuButton, MenuItem, MenuItems } from "@headlessui/react";
import { ChevronDownIcon, PlusIcon } from "@heroicons/react/16/solid";
import { EllipsisVerticalIcon } from "@heroicons/react/20/solid";
import type { Environment } from "@qltysh/fabro-api-client";

import { ApiError, apiData, environmentsApi } from "../lib/api-client";
import { useEnvironments, useServerSettings } from "../lib/queries";
import { queryKeys } from "../lib/query-keys";
import { CREATABLE_PROVIDERS } from "../components/environment-form";
import {
  Badge,
  Muted,
  Panel,
  PanelSkeleton,
  SettingsPageIntro,
} from "../components/settings-panel";
import { ConfirmDialog } from "../components/ui";
import { useToast } from "../components/toast";

// `local` is a reserved, in-memory environment the server includes only when
// the local sandbox provider is enabled. It has no configurable settings, so it
// gets its own panel instead of a row in the managed environments list.
const RESERVED_ID = "local";

const MENU_ITEM_CLASS =
  "flex w-full items-center gap-2 px-3 py-2 text-left text-sm text-fg-3 transition-colors data-focus:bg-overlay data-focus:text-fg data-focus:outline-hidden disabled:cursor-not-allowed disabled:opacity-60";

const MENU_ITEM_DANGER_CLASS =
  "flex w-full items-center gap-2 px-3 py-2 text-left text-sm text-coral transition-colors data-focus:bg-coral/10 data-focus:text-coral data-focus:outline-hidden disabled:cursor-not-allowed disabled:opacity-60";

export function meta() {
  return [{ title: "Environments — Fabro" }];
}

const DESCRIPTION =
  "Environments are server-managed runtime definitions — provider, image, resources, network, and lifecycle — that workflow runs select by id. They are operator policy stored on this Fabro server.";

export default function SettingsEnvironments() {
  const query = useEnvironments();

  return (
    <div className="space-y-6">
      <SettingsPageIntro description={DESCRIPTION} action={<NewEnvironmentMenu />} />
      {query.data ? (
        <EnvironmentsContent environments={query.data.data} />
      ) : query.error ? (
        <Panel title="Environments">
          <div className="px-4 py-6 text-sm text-fg-2">
            Couldn&apos;t load environments. Please try again.
          </div>
        </Panel>
      ) : (
        <PanelSkeleton />
      )}
    </div>
  );
}

const NEW_BUTTON_CLASS =
  "inline-flex items-center gap-1.5 rounded-md border border-line bg-panel/80 px-2.5 py-1 text-sm font-medium text-fg-3 transition-colors hover:border-line-strong hover:bg-panel hover:text-fg disabled:cursor-not-allowed disabled:opacity-60 disabled:hover:border-line disabled:hover:bg-panel/80 disabled:hover:text-fg-3";

function providerLabel(provider: string): string {
  return provider.charAt(0).toUpperCase() + provider.slice(1);
}

// "New environment" is a provider picker: each enabled sandbox provider opens
// the create form pre-set to that provider, which is then fixed for the
// environment's lifetime. `local` is never offered (it's reserved/in-memory).
function NewEnvironmentMenu() {
  const { data } = useServerSettings();
  const providers = data
    ? CREATABLE_PROVIDERS.filter((provider) => data.server.sandbox.providers[provider].enabled)
    : [];

  if (providers.length === 0) {
    return (
      <button
        type="button"
        disabled
        title={data ? "Enable a sandbox provider to create environments" : "Loading providers…"}
        className={NEW_BUTTON_CLASS}
      >
        <PlusIcon className="size-3.5" aria-hidden="true" />
        New environment
      </button>
    );
  }

  return (
    <Menu as="div" className="relative inline-block">
      <MenuButton className={NEW_BUTTON_CLASS}>
        <PlusIcon className="size-3.5" aria-hidden="true" />
        New environment
        <ChevronDownIcon className="size-3.5" aria-hidden="true" />
      </MenuButton>
      <MenuItems
        transition
        anchor={{ to: "bottom end", gap: 4 }}
        className="z-30 w-44 origin-top-right rounded-md bg-panel py-1 outline-1 -outline-offset-1 outline-line-strong transition data-closed:scale-95 data-closed:opacity-0 data-enter:duration-100 data-enter:ease-out data-leave:duration-75 data-leave:ease-in"
      >
        {providers.map((provider) => (
          <MenuItem key={provider}>
            <Link
              to={`/settings/environments/new?provider=${encodeURIComponent(provider)}`}
              className={MENU_ITEM_CLASS}
            >
              {providerLabel(provider)}
            </Link>
          </MenuItem>
        ))}
      </MenuItems>
    </Menu>
  );
}

function EnvironmentsContent({ environments }: { environments: Environment[] }) {
  const local = environments.find((environment) => environment.id === RESERVED_ID);
  const managed = environments.filter((environment) => environment.id !== RESERVED_ID);
  return (
    <>
      <EnvironmentsPanel environments={managed} />
      {local ? <LocalEnvironmentPanel environment={local} /> : null}
    </>
  );
}

function LocalEnvironmentPanel({ environment }: { environment: Environment }) {
  return (
    <Panel title="Local sandbox">
      <div className="flex items-start justify-between gap-4 px-4 py-3.5">
        <div className="min-w-0">
          <div className="flex items-center gap-2">
            <span className="font-mono text-sm text-fg">{environment.id}</span>
            <Badge>{environment.provider}</Badge>
          </div>
          <p className="mt-1 text-xs/5 text-fg-3 text-pretty">
            Built-in environment that runs tools directly on the host. Available because the local
            sandbox provider is enabled; it has no configurable settings and can&apos;t be edited or
            deleted.
          </p>
        </div>
        <StatusTag>reserved</StatusTag>
      </div>
    </Panel>
  );
}

function EnvironmentsPanel({ environments }: { environments: Environment[] }) {
  const { mutate } = useSWRConfig();
  const toast = useToast();
  const [pendingDelete, setPendingDelete] = useState<Environment | null>(null);
  const [deleting, setDeleting] = useState(false);

  async function confirmDelete() {
    if (!pendingDelete) return;
    const target = pendingDelete;
    setDeleting(true);
    try {
      await apiData(() => environmentsApi.deleteEnvironment(target.id, target.revision));
      await mutate(queryKeys.environments.list());
      toast.push({ message: `Environment “${target.id}” deleted.` });
      setPendingDelete(null);
    } catch (cause) {
      toast.push({
        tone: "error",
        message:
          cause instanceof ApiError && cause.message
            ? cause.message
            : "Couldn't delete the environment. Please try again.",
      });
    } finally {
      setDeleting(false);
    }
  }

  return (
    <>
      <Panel title="Environments">
        {environments.length === 0 ? (
          <div className="px-4 py-6 text-sm text-fg-muted">
            No environments defined yet.
          </div>
        ) : (
          environments.map((environment) => (
            <EnvironmentRow
              key={environment.id}
              environment={environment}
              disabled={deleting}
              onDelete={() => setPendingDelete(environment)}
            />
          ))
        )}
      </Panel>
      <ConfirmDialog
        open={pendingDelete !== null}
        title="Delete environment"
        description={
          <>
            Delete{" "}
            <span className="font-mono text-fg-2">{pendingDelete?.id}</span>? Runs that
            select this environment will fail until it is recreated.
          </>
        }
        confirmLabel="Delete"
        pendingLabel="Deleting…"
        pending={deleting}
        onConfirm={confirmDelete}
        onCancel={() => {
          if (!deleting) setPendingDelete(null);
        }}
      />
    </>
  );
}

function EnvironmentRow({
  environment,
  disabled,
  onDelete,
}: {
  environment: Environment;
  disabled: boolean;
  onDelete: () => void;
}) {
  return (
    <div className="grid grid-cols-[minmax(0,1fr)_minmax(0,1.5fr)_auto] items-center gap-4 px-4 py-3.5">
      <div className="min-w-0">
        <div className="flex items-center gap-2">
          <span className="truncate font-mono text-sm text-fg" title={environment.id}>
            {environment.id}
          </span>
          <Badge>{environment.provider}</Badge>
        </div>
        <div className="mt-0.5 truncate text-xs/5 text-fg-3">
          {resourcesSummary(environment)}
        </div>
      </div>
      <div
        className="min-w-0 truncate font-mono text-xs text-fg-2"
        title={imageSummary(environment) ?? undefined}
      >
        {imageSummary(environment) ?? <Muted>No image</Muted>}
      </div>
      <RowMenu environment={environment} disabled={disabled} onDelete={onDelete} />
    </div>
  );
}

function imageSummary(environment: Environment): string | null {
  if (environment.image.docker) return environment.image.docker;
  if (environment.image.dockerfile) return "Dockerfile (inline)";
  return null;
}

function resourcesSummary(environment: Environment): string {
  const parts = [
    environment.resources.cpu === null ? null : `${environment.resources.cpu} CPU`,
    environment.resources.memory,
    environment.resources.disk,
  ].filter((part): part is string => Boolean(part));
  return parts.length > 0 ? parts.join(" · ") : "Default resources";
}

function StatusTag({ children }: { children: string }) {
  return (
    <span className="rounded-sm bg-overlay px-1.5 py-0.5 text-[10px] font-medium uppercase tracking-wide text-fg-muted">
      {children}
    </span>
  );
}

function RowMenu({
  environment,
  disabled,
  onDelete,
}: {
  environment: Environment;
  disabled: boolean;
  onDelete: () => void;
}) {
  return (
    <Menu as="div" className="relative inline-block">
      <MenuButton
        type="button"
        disabled={disabled}
        aria-label={`Actions for ${environment.id}`}
        title="Actions"
        className="flex size-7 items-center justify-center rounded text-fg-muted transition-colors hover:bg-overlay hover:text-fg-3 disabled:cursor-not-allowed disabled:opacity-60"
      >
        <EllipsisVerticalIcon className="size-4" aria-hidden="true" />
      </MenuButton>
      <MenuItems
        transition
        anchor={{ to: "bottom end", gap: 4 }}
        className="z-30 w-36 origin-top-right rounded-md bg-panel py-1 outline-1 -outline-offset-1 outline-line-strong transition data-closed:scale-95 data-closed:opacity-0 data-enter:duration-100 data-enter:ease-out data-leave:duration-75 data-leave:ease-in"
      >
        <MenuItem>
          <Link
            to={`/settings/environments/${encodeURIComponent(environment.id)}/edit`}
            className={MENU_ITEM_CLASS}
          >
            Edit
          </Link>
        </MenuItem>
        <hr className="my-1 h-px border-0 bg-line" />
        <MenuItem>
          <button
            type="button"
            onClick={onDelete}
            disabled={disabled}
            className={MENU_ITEM_DANGER_CLASS}
          >
            Delete
          </button>
        </MenuItem>
      </MenuItems>
    </Menu>
  );
}