import type {Config as SvelteConfig} from '@sveltejs/kit';

import type {CompileOptions, ModuleCompileOptions, PreprocessorGroup} from 'svelte/compiler';

import {join} from 'node:path';

import {EMPTY_OBJECT} from '@fuzdev/fuz_util/object.js';

import {SVELTE_CONFIG_FILENAME} from './constants.ts';

/* eslint-disable @typescript-eslint/no-deprecated */

// see https://github.com/sveltejs/kit/discussions/14240

/*

This module is intended to have minimal dependencies to avoid over-imports in the CLI.

*/

/**

* Loads a SvelteKit config at `dir`.

* @returns `null` if no config is found

*/

export const load_svelte_config = async ({

dir = process.cwd(),

config_filename = SVELTE_CONFIG_FILENAME,

}: {dir?: string; config_filename?: string} = EMPTY_OBJECT): Promise<SvelteConfig | null> => {

try {

return (await import(join(dir, config_filename))).default;

} catch (_err) {

return null;

}

};

/**

* A subset of SvelteKit's config in a form that Gro uses

* because SvelteKit doesn't expose its config resolver.

* Flattens things out to keep them simple and easy to pass around,

* and doesn't deal with most properties, but includes the full `svelte_config`.

* The `base` and `assets` in particular are renamed for clarity with Gro's internal systems,

* so these properties become first-class vocabulary inside Gro.

*/

export interface ParsedSvelteConfig {

// TODO probably fill these out with defaults

svelte_config: SvelteConfig | null;

alias: Record<string, string>;

base_url: '' | `/${string}` | undefined;

assets_url: '' | `http://${string}` | `https://${string}` | undefined;

// TODO others, but maybe replace with a Zod schema? https://svelte.dev/docs/kit/configuration

/**

* Same as the SvelteKit `files.assets`.

*/

assets_path: string;

/**

* Same as the SvelteKit `files.lib`.

*/

lib_path: string;

/**

* Same as the SvelteKit `files.routes`.

*/

routes_path: string;

env_dir: string | undefined;

private_prefix: string | undefined;

public_prefix: string | undefined;

svelte_compile_options: CompileOptions;

svelte_compile_module_options: ModuleCompileOptions;

svelte_preprocessors: PreprocessorGroup | Array<PreprocessorGroup> | undefined;

}

// TODO currently incomplete and hack - maybe rethink

/**

* Returns Gro-relevant properties of a SvelteKit config

* as a convenience wrapper around `load_svelte_config`.

* Needed because SvelteKit doesn't expose its config resolver.

*/

export const parse_svelte_config = async ({

dir_or_config = process.cwd(), // TODO maybe not the best API, maybe a type union? `({svelte_config} | {dir}) & {config_filename}`

config_filename = SVELTE_CONFIG_FILENAME,

}: {

dir_or_config?: string | SvelteConfig;

config_filename?: string;

} = EMPTY_OBJECT): Promise<ParsedSvelteConfig> => {

const svelte_config =

typeof dir_or_config === 'string'

? await load_svelte_config({dir: dir_or_config, config_filename})

: dir_or_config;

const kit = svelte_config?.kit;

const alias = {$lib: 'src/lib', ...kit?.alias};

const base_url = kit?.paths?.base;

const assets_url = kit?.paths?.assets;

// TODO probably a Zod schema instead

const assets_path = kit?.files?.assets ?? 'static';

const lib_path = kit?.files?.lib ?? 'src/lib';

const routes_path = kit?.files?.routes ?? 'src/routes';

const env_dir = kit?.env?.dir;

const private_prefix = kit?.env?.privatePrefix;

const public_prefix = kit?.env?.publicPrefix;

const svelte_compile_options: CompileOptions = svelte_config?.compilerOptions ?? {};

// Change the default to `generate: 'server'`,

// because SvelteKit handles the client in the normal cases.

if (svelte_compile_options.generate === undefined) {

svelte_compile_options.generate = 'server';

}

const svelte_compile_module_options = to_default_compile_module_options(svelte_compile_options); // TODO will kit have these separately?

const svelte_preprocessors = svelte_config?.preprocess;

return {

svelte_config,

alias,

base_url,

assets_url,

assets_path,

lib_path,

routes_path,

env_dir,

private_prefix,

public_prefix,

svelte_compile_options,

svelte_compile_module_options,

svelte_preprocessors,

};

};

export const to_default_compile_module_options = ({

dev,

generate,

filename,

rootDir,

warningFilter,

}: CompileOptions): ModuleCompileOptions => ({dev, generate, filename, rootDir, warningFilter});

/**

* The parsed SvelteKit config for the cwd, cached globally at the module level.

*/

export const default_svelte_config = await parse_svelte_config(); // always load it to keep things simple ahead