import { useCallback, useEffect, useState } from "react";

import type {
  AgentProfile,
  GatewayError,
  LocalModelServerConfig,
  OpenCodeConfig,
  OpenCodeProviderCatalogEntry,
} from "@/domain";
import { useGateways } from "@/app/di";
import { Button, IconButton, Input, SmallDropdown, cn } from "@/shared";
import { ModelServerSelect } from "@/features/model-servers";
import {
  defaultOpenCodeConfig,
  type ProfileErrors,
} from "./profile";

/** A small caption above a control. */
function Caption({ children }: { children: React.ReactNode }) {
  return <span className="text-xs font-medium text-muted">{children}</span>;
}

function describeError(e: unknown): string {
  if (e && typeof e === "object" && "message" in e) {
    return String((e as GatewayError).message);
  }
  return String(e);
}

/** View-model for the OpenCode cloud-provider catalogue (ticket #92). */
export interface OpenCodeProviderCatalog {
  providers: OpenCodeProviderCatalogEntry[] | null;
  loading: boolean;
  error: string | null;
  reload: () => void;
}

/**
 * Loads the static OpenCode cloud-provider catalogue once for the whole form
 * surface, so Cloud OpenCode rows share the same provider/model options.
 */
export function useOpenCodeProviderCatalog(): OpenCodeProviderCatalog {
  const { profile } = useGateways();
  const [providers, setProviders] = useState<OpenCodeProviderCatalogEntry[] | null>(
    null,
  );
  const [loading, setLoading] = useState(false);
  const [error, setError] = useState<string | null>(null);

  const load = useCallback(async () => {
    setLoading(true);
    setError(null);
    try {
      setProviders(await profile.listOpenCodeProviders());
    } catch (e) {
      setProviders(null);
      setError(describeError(e));
    } finally {
      setLoading(false);
    }
  }, [profile]);

  useEffect(() => {
    void load();
  }, [load]);

  return { providers, loading, error, reload: () => void load() };
}

/**
 * Segmented control choosing whether an OpenCode profile runs against the local
 * `llama.cpp` endpoint or a cloud provider from the OpenCode registry.
 */
export function OpenCodeModeFields({
  profile,
  errors,
  servers,
  providerCatalog,
  onChange,
}: {
  profile: AgentProfile;
  errors: ProfileErrors;
  servers: LocalModelServerConfig[];
  providerCatalog: OpenCodeProviderCatalog;
  onChange: (p: AgentProfile) => void;
}) {
  const [mode, setMode] = useState<"local" | "cloud">(
    profile.opencodeProvider ? "cloud" : "local",
  );

  function selectMode(next: "local" | "cloud") {
    setMode(next);
    if (next === "local" && profile.opencodeProvider) {
      onChange({
        ...profile,
        opencode: profile.opencode ?? defaultOpenCodeConfig(),
        opencodeProvider: undefined,
      });
    }
  }

  return (
    <div className="mt-1 flex flex-col gap-2">
      <div
        role="radiogroup"
        aria-label="mode du profil OpenCode"
        className="flex w-fit gap-1 rounded-md border border-border bg-raised p-0.5"
      >
        {(
          [
            { id: "local", label: "Local (llama.cpp)" },
            { id: "cloud", label: "Provider cloud" },
          ] as const
        ).map((seg) => {
          const active = mode === seg.id;
          return (
            <button
              key={seg.id}
              type="button"
              role="radio"
              aria-checked={active}
              onClick={() => selectMode(seg.id)}
              className={cn(
                "rounded px-2.5 py-1 text-xs font-medium transition-colors",
                active
                  ? "bg-primary text-on-primary"
                  : "text-muted hover:text-content",
              )}
            >
              {seg.label}
            </button>
          );
        })}
      </div>

      {mode === "local" && (
        <OpenCodeFields
          profile={profile}
          errors={errors}
          servers={servers}
          onChange={onChange}
        />
      )}

      {mode === "cloud" && (
        <OpenCodeProviderFields
          profile={profile}
          catalog={providerCatalog}
          onChange={onChange}
        />
      )}
    </div>
  );
}

/** Field-keyed validation errors for the Cloud sub-form, surfaced on submit. */
interface CloudFieldErrors {
  providerId?: string;
  model?: string;
  apiKey?: string;
  npm?: string;
  baseUrl?: string;
}

/** Sentinel `<option>` value picking the custom-provider sub-form. */
const CUSTOM_PROVIDER_VALUE = "__custom__";

/** Default AI SDK package pre-filled for a fresh custom-provider draft. */
const DEFAULT_CUSTOM_NPM = "@ai-sdk/openai-compatible";

function OpenCodeProviderFields({
  profile,
  catalog,
  onChange,
}: {
  profile: AgentProfile;
  catalog: OpenCodeProviderCatalog;
  onChange: (p: AgentProfile) => void;
}) {
  const { profile: profileGateway } = useGateways();
  const existing = profile.opencodeProvider;
  const [mode, setMode] = useState<"catalog" | "custom">(
    existing?.custom ? "custom" : "catalog",
  );
  const [providerId, setProviderId] = useState(existing?.providerId ?? "");
  const [model, setModel] = useState(existing?.model ?? "");
  const [providerFilter, setProviderFilter] = useState("");
  const [customNpm, setCustomNpm] = useState(existing?.custom?.npm ?? DEFAULT_CUSTOM_NPM);
  const [customBaseUrl, setCustomBaseUrl] = useState(existing?.custom?.baseUrl ?? "");
  const [customDisplayName, setCustomDisplayName] = useState(
    existing?.custom?.displayName ?? "",
  );
  const [apiKey, setApiKey] = useState("");
  const [showKey, setShowKey] = useState(false);
  const [saving, setSaving] = useState(false);
  const [saveError, setSaveError] = useState<string | null>(null);
  const [fieldErrors, setFieldErrors] = useState<CloudFieldErrors>({});

  const isEditing = existing !== undefined;
  const models =
    catalog.providers?.find((p) => p.providerId === providerId)?.models ?? [];
  const catalogReady = catalog.providers !== null && !catalog.loading;
  const filteredProviders = (catalog.providers ?? []).filter((p) => {
    if (p.providerId === providerId) return true;
    const q = providerFilter.trim().toLowerCase();
    if (q.length === 0) return true;
    return (
      p.displayName.toLowerCase().includes(q) ||
      p.providerId.toLowerCase().includes(q)
    );
  });
  const saveDisabled =
    saving ||
    apiKey.length === 0 ||
    (mode === "catalog" && (!catalogReady || Boolean(catalog.error)));

  async function save() {
    const errors: CloudFieldErrors = {};
    if (providerId.trim().length === 0) {
      errors.providerId = "Le provider est obligatoire.";
    }
    if (model.trim().length === 0) errors.model = "Le modèle est obligatoire.";
    if (mode === "custom") {
      if (customNpm.trim().length === 0) errors.npm = "Le paquet npm est obligatoire.";
      if (customBaseUrl.trim().length === 0) {
        errors.baseUrl = "L'URL de base est obligatoire.";
      }
    }
    if (apiKey.length === 0) errors.apiKey = "La clé API est obligatoire.";
    setFieldErrors(errors);
    if (Object.keys(errors).length > 0) return;

    setSaving(true);
    setSaveError(null);
    try {
      const saved = await profileGateway.saveOpenCodeProviderProfile({
        profile,
        providerId: providerId.trim(),
        model: model.trim(),
        apiKey,
        ...(mode === "custom"
          ? {
              custom: {
                npm: customNpm.trim(),
                baseUrl: customBaseUrl.trim(),
                displayName:
                  customDisplayName.trim().length > 0
                    ? customDisplayName.trim()
                    : undefined,
              },
            }
          : {}),
      });
      onChange(saved);
      setApiKey("");
    } catch (e) {
      setSaveError(describeError(e));
    } finally {
      setSaving(false);
    }
  }

  return (
    <fieldset className="mt-1 flex flex-col gap-2 rounded-md border border-border/70 p-2">
      <legend className="px-1 text-xs font-medium text-muted">
        Provider cloud (OpenCode)
      </legend>

      {saveError && (
        <p role="alert" className="text-sm text-danger">
          {saveError}
        </p>
      )}

      {catalog.loading && (
        <p className="text-xs text-faint">Chargement des providers…</p>
      )}
      {catalog.error && (
        <div className="flex flex-col gap-1">
          <p role="alert" className="text-sm text-danger">
            Impossible de charger la liste des providers cloud.
          </p>
          <Button size="sm" onClick={() => catalog.reload()} className="w-fit">
            Réessayer
          </Button>
        </div>
      )}

      {mode === "catalog" && (
        <>
          <label className="flex flex-col gap-1">
            <Caption>Provider</Caption>
            {catalogReady && (
              <input
                type="text"
                aria-label={`${profile.name} provider search`}
                placeholder="Rechercher un provider…"
                value={providerFilter}
                onChange={(e) => setProviderFilter(e.target.value)}
                className="h-8 w-full rounded-md border border-border bg-raised px-3 text-xs text-content outline-none"
              />
            )}
            <SmallDropdown
              aria-label={`${profile.name} provider`}
              value={providerId}
              disabled={!catalogReady}
              onChange={(v) => {
                if (v === CUSTOM_PROVIDER_VALUE) {
                  setMode("custom");
                  setProviderId("");
                  setModel("");
                } else {
                  setProviderId(v);
                  setModel("");
                }
                setFieldErrors((prev) => ({ ...prev, providerId: undefined }));
              }}
              className="w-full"
              size="md"
              invalid={Boolean(fieldErrors.providerId)}
              options={[
                {
                  value: "",
                  label: catalog.loading
                    ? "Chargement des providers…"
                    : "Choisir un provider…",
                  disabled: true,
                },
                ...filteredProviders.map((p) => ({
                  value: p.providerId,
                  label: p.displayName,
                })),
                {
                  value: CUSTOM_PROVIDER_VALUE,
                  label: "Autre / personnalisé…",
                },
              ]}
            />
            {fieldErrors.providerId && (
              <small className="text-xs text-danger">{fieldErrors.providerId}</small>
            )}
          </label>

          <label className="flex flex-col gap-1">
            <Caption>Modèle</Caption>
            <SmallDropdown
              aria-label={`${profile.name} model`}
              value={model}
              disabled={providerId.length === 0}
              onChange={(next) => {
                setModel(next);
                setFieldErrors((prev) => ({ ...prev, model: undefined }));
              }}
              className="w-full"
              size="md"
              invalid={Boolean(fieldErrors.model)}
              options={[
                {
                  value: "",
                  label: providerId.length === 0 ? "—" : "Choisir un modèle…",
                  disabled: true,
                },
                ...models.map((m) => ({ value: m, label: m })),
              ]}
            />
            {fieldErrors.model && (
              <small className="text-xs text-danger">{fieldErrors.model}</small>
            )}
          </label>
        </>
      )}

      {mode === "custom" && (
        <fieldset className="flex flex-col gap-2 rounded-md border border-border/50 p-2">
          <legend className="px-1 text-xs font-medium text-muted">
            Provider personnalisé
          </legend>

          <Button
            variant="ghost"
            size="sm"
            className="w-fit"
            onClick={() => {
              setMode("catalog");
              setProviderId("");
              setModel("");
              setFieldErrors({});
            }}
          >
            ← Choisir un provider du catalogue
          </Button>

          <label className="flex flex-col gap-1">
            <Caption>Identifiant du provider</Caption>
            <Input
              aria-label={`${profile.name} custom provider id`}
              value={providerId}
              placeholder="ex. mon-provider"
              invalid={Boolean(fieldErrors.providerId)}
              onChange={(e) => {
                setProviderId(e.target.value);
                setFieldErrors((prev) => ({ ...prev, providerId: undefined }));
              }}
            />
            {fieldErrors.providerId && (
              <small className="text-xs text-danger">{fieldErrors.providerId}</small>
            )}
          </label>

          <label className="flex flex-col gap-1">
            <Caption>Paquet npm</Caption>
            <Input
              aria-label={`${profile.name} custom npm package`}
              value={customNpm}
              placeholder={DEFAULT_CUSTOM_NPM}
              invalid={Boolean(fieldErrors.npm)}
              onChange={(e) => {
                setCustomNpm(e.target.value);
                setFieldErrors((prev) => ({ ...prev, npm: undefined }));
              }}
            />
            {fieldErrors.npm && (
              <small className="text-xs text-danger">{fieldErrors.npm}</small>
            )}
          </label>

          <label className="flex flex-col gap-1">
            <Caption>URL de base</Caption>
            <Input
              aria-label={`${profile.name} custom base url`}
              value={customBaseUrl}
              placeholder="https://api.mon-provider.example/v1"
              invalid={Boolean(fieldErrors.baseUrl)}
              onChange={(e) => {
                setCustomBaseUrl(e.target.value);
                setFieldErrors((prev) => ({ ...prev, baseUrl: undefined }));
              }}
            />
            {fieldErrors.baseUrl && (
              <small className="text-xs text-danger">{fieldErrors.baseUrl}</small>
            )}
          </label>

          <label className="flex flex-col gap-1">
            <Caption>Modèle</Caption>
            <Input
              aria-label={`${profile.name} model`}
              value={model}
              placeholder="ex. mon-modele-1"
              invalid={Boolean(fieldErrors.model)}
              onChange={(e) => {
                setModel(e.target.value);
                setFieldErrors((prev) => ({ ...prev, model: undefined }));
              }}
            />
            {fieldErrors.model && (
              <small className="text-xs text-danger">{fieldErrors.model}</small>
            )}
          </label>

          <label className="flex flex-col gap-1">
            <Caption>Libellé du modèle (optionnel)</Caption>
            <Input
              aria-label={`${profile.name} custom display name`}
              value={customDisplayName}
              placeholder="ex. Mon modèle"
              onChange={(e) => setCustomDisplayName(e.target.value)}
            />
          </label>
        </fieldset>
      )}

      <label className="flex flex-col gap-1">
        <Caption>Clé API</Caption>
        <div className="flex items-center gap-1">
          <Input
            aria-label={`${profile.name} api key`}
            type={showKey ? "text" : "password"}
            value={apiKey}
            placeholder={
              isEditing
                ? "Ressaisissez la clé API pour confirmer l'enregistrement"
                : "ex. sk-ant-…"
            }
            invalid={Boolean(fieldErrors.apiKey)}
            onChange={(e) => {
              setApiKey(e.target.value);
              setFieldErrors((prev) => ({ ...prev, apiKey: undefined }));
            }}
          />
          <IconButton
            size="sm"
            aria-label="afficher/masquer la clé API"
            onClick={() => setShowKey((v) => !v)}
          >
            {showKey ? "🙈" : "👁"}
          </IconButton>
        </div>
        {fieldErrors.apiKey && (
          <small className="text-xs text-danger">{fieldErrors.apiKey}</small>
        )}
        <small className="text-xs text-faint">
          Jamais affichée ni renvoyée par IdeA une fois enregistrée ; stockée
          chiffrée localement.
        </small>
        {isEditing && (
          <small className="text-xs text-muted">
            Pour des raisons de sécurité, la clé n&apos;est jamais réaffichée :
            ressaisissez-la à chaque modification de ce profil.
          </small>
        )}
      </label>

      <Button
        variant="primary"
        size="sm"
        loading={saving}
        disabled={saveDisabled}
        onClick={() => void save()}
        className="w-fit"
      >
        Enregistrer
      </Button>
    </fieldset>
  );
}

function OpenCodeFields({
  profile,
  errors,
  servers,
  onChange,
}: {
  profile: AgentProfile;
  errors: ProfileErrors;
  /** Declared local model servers (F35.2), for the binding dropdown. */
  servers: LocalModelServerConfig[];
  onChange: (p: AgentProfile) => void;
}) {
  const opencode = profile.opencode ?? defaultOpenCodeConfig();
  const patch = (next: Partial<OpenCodeConfig>) =>
    onChange({
      ...profile,
      opencode: { ...opencode, ...next },
      opencodeProvider: undefined,
    });

  return (
    <fieldset className="mt-1 flex flex-col gap-2 rounded-md border border-border/70 p-2">
      <legend className="px-1 text-xs font-medium text-muted">
        Local model (OpenCode + llama.cpp)
      </legend>

      <label className="flex flex-col gap-1">
        <Caption>Base URL</Caption>
        <Input
          aria-label={`${profile.name} base url`}
          value={opencode.baseURL}
          placeholder="http://localhost:8080/v1"
          invalid={Boolean(errors.baseURL)}
          onChange={(e) => patch({ baseURL: e.target.value })}
        />
        {errors.baseURL && (
          <small className="text-xs text-danger">{errors.baseURL}</small>
        )}
      </label>

      <label className="flex flex-col gap-1">
        <Caption>Model</Caption>
        <Input
          aria-label={`${profile.name} model`}
          value={opencode.model}
          placeholder="qwen3-coder-30b"
          invalid={Boolean(errors.model)}
          onChange={(e) => patch({ model: e.target.value })}
        />
        {errors.model && <small className="text-xs text-danger">{errors.model}</small>}
      </label>

      <label className="flex flex-col gap-1">
        <Caption>API key (optional — a local llama.cpp needs none)</Caption>
        <Input
          aria-label={`${profile.name} api key`}
          value={opencode.apiKey ?? ""}
          placeholder="e.g. sk-no-key"
          onChange={(e) => {
            const v = e.target.value;
            patch({ apiKey: v.length === 0 ? undefined : v });
          }}
        />
      </label>

      <div className="flex flex-wrap gap-4">
        <label className="flex items-center gap-2">
          <input
            type="checkbox"
            aria-label={`${profile.name} reasoning`}
            checked={opencode.reasoning ?? true}
            onChange={(e) => patch({ reasoning: e.target.checked })}
            className="accent-primary"
          />
          <Caption>Reasoning</Caption>
        </label>

        <label className="flex items-center gap-2">
          <input
            type="checkbox"
            aria-label={`${profile.name} attachment`}
            checked={opencode.attachment ?? false}
            onChange={(e) => patch({ attachment: e.target.checked })}
            className="accent-primary"
          />
          <Caption>Attachments</Caption>
        </label>
      </div>

      <label className="flex flex-col gap-1">
        <Caption>
          Local model server (bind to a managed llama.cpp server, or none)
        </Caption>
        <ModelServerSelect
          ariaLabel={`${profile.name} local model server`}
          servers={servers}
          value={opencode.localModelServerId}
          onChange={(serverId) => patch({ localModelServerId: serverId })}
        />
      </label>
    </fieldset>
  );
}
