// <ClassifierSettings> — the review classifier's runtime, model, effort and
// how many requested reviews run at once, shown and saved here
// (`GET`/`PUT /api/review-classifier/settings`). A PUT changes only the
// fields it carries: the form sends the runtime, model, effort and limit, and
// the ACP provider only while the runtime is ACP, so the stored provider
// survives a switch back. A refused save shows the route's own reason and
// leaves the form as typed. There is no API key field: admins set each
// runtime's key in the bao UI.
import { useEffect, useState } from "preact/hooks";
import { ApiErrorPanel } from "@hive/shared/api-error-panel.js";
import { readApiError, type ProblemDetails } from "@hive/shared/api-error.js";
import { Button } from "../../ui/button/Button.js";
import { Disclosure } from "../../ui/disclosure/Disclosure.js";
import { SelectField } from "../../ui/select-field/SelectField.js";
import { TextField } from "../../ui/text-field/TextField.js";
import {
  EFFORTS,
  MAX_REVIEWS,
  MIN_REVIEWS,
  changed,
  draftOf,
  settingsProblem,
  settingsSummary,
  toSettings,
  type ClassifierSettingsBody,
  type Runtime,
  type SettingsDraft,
} from "./SettingsTypes.js";
import "./ClassifierSettings.css";

const SETTINGS = "/api/review-classifier/settings";

const RUNTIME_OPTIONS = [
  { value: "api-key", label: "API key (claude)" },
  { value: "acp", label: "ACP (opencode)" },
];

// The empty effort option is the runtime's own default: claude's on the API
// key runtime, opencode's on ACP.
function effortOptions(runtime: Runtime) {
  return [
    {
      value: "",
      label: runtime === "acp" ? "opencode's default" : "claude's default",
    },
    ...EFFORTS.map((e) => ({ value: e, label: e })),
  ];
}

export function ClassifierSettings() {
  // The settings as the controller holds them; null until the first read.
  const [saved, setSaved] = useState<ClassifierSettingsBody | null>(null);
  const [draft, setDraft] = useState<SettingsDraft | null>(null);
  const [loadError, setLoadError] = useState<ProblemDetails | null>(null);
  const [saveError, setSaveError] = useState<ProblemDetails | null>(null);
  const [saving, setSaving] = useState(false);
  const [justSaved, setJustSaved] = useState(false);
  // Folded until wanted: the settings are changed now and then, and the
  // folded header says what they are.
  const [open, setOpen] = useState(false);

  useEffect(() => {
    let cancelled = false;
    void (async () => {
      try {
        const res = await fetch(SETTINGS);
        if (cancelled) return;
        if (!res.ok) {
          setLoadError(await readApiError(res));
          return;
        }
        const body = (await res.json()) as ClassifierSettingsBody;
        if (cancelled) return;
        setSaved(body);
        setDraft(draftOf(body));
      } catch (e: unknown) {
        if (!cancelled) setLoadError({ detail: String(e) });
      }
    })();
    return () => {
      cancelled = true;
    };
  }, []);

  function edit(next: SettingsDraft) {
    setDraft(next);
    setJustSaved(false);
  }

  async function save(e: Event) {
    e.preventDefault();
    if (draft === null || settingsProblem(draft) !== null) return;
    setSaving(true);
    setSaveError(null);
    setJustSaved(false);
    try {
      const res = await fetch(SETTINGS, {
        method: "PUT",
        headers: { "content-type": "application/json" },
        body: JSON.stringify(toSettings(draft)),
      });
      if (!res.ok) {
        // The form stays as typed, so the operator can fix it and save again.
        setSaveError(await readApiError(res));
        return;
      }
      const body = (await res.json()) as ClassifierSettingsBody;
      setSaved(body);
      setDraft(draftOf(body));
      setJustSaved(true);
    } catch (err: unknown) {
      setSaveError({ detail: String(err) });
    } finally {
      setSaving(false);
    }
  }

  const problem = draft === null ? null : settingsProblem(draft);

  return (
    <Disclosure
      title="classifier settings"
      icon="⚙️"
      hint={saved ? settingsSummary(saved) : undefined}
      open={open}
      onToggle={setOpen}
    >
      <p>
        The runtime, model and effort the review classifier runs with, and how
        many requested reviews run at once. The API key runtime runs claude on
        the Anthropic key; the ACP runtime runs opencode on the provider given
        here. A change takes effect from the next run, with no restart. Try-outs
        don't count toward the limit. Each runtime's key is set in the bao UI,
        not here.
      </p>
      {loadError ? (
        <ApiErrorPanel
          context="the settings could not be loaded"
          problem={loadError}
        />
      ) : null}
      {draft ? (
        <form class="ui-classifier-settings" onSubmit={(e) => void save(e)}>
          <div class="ui-classifier-settings-fields">
            <SelectField
              id="classifier-runtime"
              label="runtime"
              value={draft.runtime}
              options={RUNTIME_OPTIONS}
              onChange={(runtime) =>
                edit({ ...draft, runtime: runtime as Runtime })
              }
            />
            {draft.runtime === "api-key" ? (
              <TextField
                id="classifier-model"
                label="model"
                value={draft.model}
                placeholder="haiku"
                onInput={(model) => edit({ ...draft, model })}
              />
            ) : null}
            <SelectField
              id="classifier-effort"
              label="effort"
              value={draft.effort}
              options={effortOptions(draft.runtime)}
              onChange={(effort) => edit({ ...draft, effort })}
            />
            <TextField
              id="classifier-max"
              label={`concurrent reviews (${MIN_REVIEWS} to ${MAX_REVIEWS})`}
              value={draft.max}
              pattern="[0-9]+"
              onInput={(max) => edit({ ...draft, max })}
            />
          </div>
          {draft.runtime === "acp" ? (
            <div class="ui-classifier-settings-fields">
              <TextField
                id="classifier-acp-url"
                label="provider URL"
                value={draft.acpUrl}
                placeholder="https://llm.example/v1"
                onInput={(acpUrl) => edit({ ...draft, acpUrl })}
              />
              <TextField
                id="classifier-acp-model"
                label="provider model"
                value={draft.acpModel}
                placeholder="Qwen/Qwen3-35B"
                onInput={(acpModel) => edit({ ...draft, acpModel })}
              />
              <TextField
                id="classifier-acp-price-input"
                label="input price (USD per million tokens)"
                value={draft.priceInput}
                onInput={(priceInput) => edit({ ...draft, priceInput })}
              />
              <TextField
                id="classifier-acp-price-output"
                label="output price (USD per million tokens)"
                value={draft.priceOutput}
                onInput={(priceOutput) => edit({ ...draft, priceOutput })}
              />
              <TextField
                id="classifier-acp-price-cache-read"
                label="cache read price (optional)"
                value={draft.priceCacheRead}
                onInput={(priceCacheRead) => edit({ ...draft, priceCacheRead })}
              />
              <TextField
                id="classifier-acp-price-cache-write"
                label="cache write price (optional)"
                value={draft.priceCacheWrite}
                onInput={(priceCacheWrite) =>
                  edit({ ...draft, priceCacheWrite })
                }
              />
            </div>
          ) : null}
          {saveError ? (
            <ApiErrorPanel
              context="the settings were not saved"
              problem={saveError}
            />
          ) : null}
          <div class="ui-classifier-settings-actions">
            <Button
              variant="primary"
              type="submit"
              disabled={saving || problem !== null || !changed(draft, saved)}
            >
              {saving ? "saving…" : "save"}
            </Button>
            {justSaved ? (
              <span class="ui-classifier-settings-note" role="status">
                Saved.
              </span>
            ) : null}
          </div>
          {problem !== null ? (
            <p class="ui-classifier-settings-note">{problem}</p>
          ) : null}
        </form>
      ) : null}
    </Disclosure>
  );
}