import * as db from '../../db/category.js';

function parsePositiveInt(value, field) {
    const id = Number(value);
    if (!Number.isInteger(id) || id <= 0) {
        return { error: `${field} is required` };
    }
    return { id };
}

function categoryErrorStatus(error) {
    if (error.message === 'Not authorized') return 403;
    if (error.message === 'Company not found') return 404;
    if (error.message === 'Parent not found') return 404;
    if (error.message === 'Cannot delete root category') return 400;
    return 500;
}

/**
 * Registers category routes (requires auth middleware).
 * @param {import('express').Application} app - Express app
 * @param {string} [basePath=''] - Optional URL prefix for all routes in this module
 */
export function register(app, basePath = '') {
    /**
     * @route GET /category/tree
     * @description Returns the category tree for the authenticated user's selected company.
     * @returns {Object} 200 - `{ languageId, tree, articles }`
     */
    app.get(`${basePath}/category/tree`, async (req, res) => {
        const companyId = req.user.selectedCompanyId;
        if (companyId == null) {
            return res.status(400).json({ error: 'No company selected' });
        }

        try {
            const result = await db.getTreeForCompany(req.user.id, companyId);
            res.status(200).json(result);
        } catch (error) {
            const status = categoryErrorStatus(error);
            if (status === 500) console.error('Get category tree failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    /**
     * @route POST /category
     * @description Creates a category under an authorized parent.
     * @body {number} parentId
     * @body {string} name
     * @returns {Object} 201 - `{ category: { id, parentId, sort, name } }`
     */
    app.post(`${basePath}/category`, async (req, res) => {
        const parent = parsePositiveInt(req.body?.parentId, 'parentId');
        if (parent.error) {
            return res.status(400).json({ error: parent.error });
        }

        const name = typeof req.body?.name === 'string' ? req.body.name.trim() : '';
        if (!name) {
            return res.status(400).json({ error: 'name is required' });
        }

        try {
            const category = await db.createUnderParent({
                googleAuthId: req.user.id,
                parentId: parent.id,
                name,
            });
            res.status(201).json({ category });
        } catch (error) {
            const status = categoryErrorStatus(error);
            if (status === 500) console.error('Create category failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    /**
     * @route GET /category/:id/articles
     * @description Returns articles in a category the user is authorized for.
     * @returns {Object} 200 - `{ articles }`
     */
    app.get(`${basePath}/category/:id/articles`, async (req, res) => {
        const parsed = parsePositiveInt(req.params.id, 'id');
        if (parsed.error) {
            return res.status(400).json({ error: parsed.error });
        }

        try {
            const articles = await db.getCategoryArticles(req.user.id, parsed.id);
            res.status(200).json({ articles });
        } catch (error) {
            const status = categoryErrorStatus(error);
            if (status === 500) console.error('Get category articles failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    /**
     * @route DELETE /category/:id
     * @description Deletes a category the user is authorized for (not the company root).
     * @returns {Object} 204 - No content
     */
    app.delete(`${basePath}/category/:id`, async (req, res) => {
        const parsed = parsePositiveInt(req.params.id, 'id');
        if (parsed.error) {
            return res.status(400).json({ error: parsed.error });
        }

        try {
            await db.deleteCategory({
                googleAuthId: req.user.id,
                id: parsed.id,
            });
            res.sendStatus(204);
        } catch (error) {
            const status = categoryErrorStatus(error);
            if (status === 500) console.error('Delete category failed:', error);
            res.status(status).json({ error: error.message });
        }
    });
}