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

// #region Helpers

/** Implicit groups created by the system — name locked. */
const LOCKED_NAMES = new Set(['POS', 'Lieferanten']);

function requireSelectedCompany(req) {
    const companyId = req.user.selectedCompanyId;
    if (companyId == null) {
        return { error: 'No company selected' };
    }
    return { companyId };
}

function customergroupErrorStatus(error) {
    if (error.message === 'No company selected') return 400;
    if (error.message === 'Not authorized') return 403;
    if (error.message === 'Company not found') return 404;
    if (error.message === 'Customer group not found') return 404;
    if (error.message === 'Name required') return 400;
    if (error.message === 'Name not allowed') return 400;
    if (error.message === 'Name cannot be changed') return 400;
    if (error.message === 'Invalid customer group order') return 400;
    if (error.message === 'Customer group in use') return 409;
    return 500;
}

function withEditable(row) {
    return {
        ...row,
        editable: !LOCKED_NAMES.has(row.name),
    };
}

// #endregion

/**
 * Registers customergroup routes for the authenticated user's selected company.
 * @param {import('express').Application} app
 * @param {string} [basePath='']
 */
export function register(app, basePath = '') {
    /**
     * @openapi
     * /customergroup:
     *   get:
     *     tags: [Customergroup]
     *     summary: List customer groups
     *     description: |
     *       Lists customer groups for the selected company, ordered by `sort`.
     *       Each item includes `editable`: `false` for implicit `POS` / `Lieferanten`
     *       (name locked), `true` otherwise. Reorder via `PUT /customergroup/order`.
     *     security:
     *       - cookieAuth: []
     *     x-markdown: customergroup/list.md
     *     responses:
     *       200:
     *         description: Customer group list
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 customergroups:
     *                   type: array
     *                   items:
     *                     $ref: '#/components/schemas/CustomergroupListItem'
     *       400:
     *         description: No company selected
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       403:
     *         description: Not authorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Company not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *   post:
     *     tags: [Customergroup]
     *     summary: Create customer group
     *     description: |
     *       Creates a customer group for the selected company.
     *       Appends with the next `sort` index. Reserved names `POS` and `Lieferanten`
     *       are not allowed (`Name not allowed`).
     *     security:
     *       - cookieAuth: []
     *     x-markdown: customergroup/create.md
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             type: object
     *             required: [name]
     *             properties:
     *               name:
     *                 type: string
     *             example:
     *               name: Kunden
     *     responses:
     *       201:
     *         description: Created customer group
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 customergroup:
     *                   $ref: '#/components/schemas/Customergroup'
     *       400:
     *         description: Name required, name not allowed, or no company selected
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       403:
     *         description: Not authorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Company not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region GET /customergroup

    app.get(`${basePath}/customergroup`, async (req, res) => {
        const selected = requireSelectedCompany(req);
        if (selected.error) {
            return res.status(400).json({ error: selected.error });
        }

        try {
            const rows = await db.list(req.user.id);
            res.status(200).json({ customergroups: rows.map(withEditable) });
        } catch (error) {
            const status = customergroupErrorStatus(error);
            if (status === 500) console.error('List customergroups failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    // #region POST /customergroup

    app.post(`${basePath}/customergroup`, async (req, res) => {
        const selected = requireSelectedCompany(req);
        if (selected.error) {
            return res.status(400).json({ error: selected.error });
        }

        const { name } = req.body ?? {};

        try {
            const customergroup = await db.create(req.user.id, { name });
            res.status(201).json({ customergroup });
        } catch (error) {
            const status = customergroupErrorStatus(error);
            if (status === 500) console.error('Create customergroup failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    /**
     * @openapi
     * /customergroup/order:
     *   put:
     *     tags: [Customergroup]
     *     summary: Reorder customer groups
     *     description: |
     *       Sets `sort` to each id’s index `0…n-1` in one transaction.
     *       `customergroupIds` must be exactly the company’s groups (same set, no dups)
     *       else `Invalid customer group order`.
     *     security:
     *       - cookieAuth: []
     *     x-markdown: customergroup/order.md
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             type: object
     *             required: [customergroupIds]
     *             properties:
     *               customergroupIds:
     *                 type: array
     *                 items:
     *                   type: integer
     *             example:
     *               customergroupIds: [4, 3, 1, 2]
     *     responses:
     *       200:
     *         description: New order
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 customergroupIds:
     *                   type: array
     *                   items:
     *                     type: integer
     *       400:
     *         description: Invalid customer group order or no company selected
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       403:
     *         description: Not authorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Company not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region PUT /customergroup/order

    app.put(`${basePath}/customergroup/order`, async (req, res) => {
        const selected = requireSelectedCompany(req);
        if (selected.error) {
            return res.status(400).json({ error: selected.error });
        }

        const rawIds = req.body?.customergroupIds;
        if (!Array.isArray(rawIds)) {
            return res.status(400).json({ error: 'customergroupIds is required' });
        }
        const customergroupIds = [];
        for (const value of rawIds) {
            const id = Number(value);
            if (!Number.isInteger(id) || id <= 0) {
                return res.status(400).json({ error: 'customergroupIds must be positive integers' });
            }
            customergroupIds.push(id);
        }

        try {
            const result = await db.order(req.user.id, { customergroupIds });
            res.status(200).json(result);
        } catch (error) {
            const status = customergroupErrorStatus(error);
            if (status === 500) console.error('Order customergroups failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    /**
     * @openapi
     * /customergroup/{id}:
     *   patch:
     *     tags: [Customergroup]
     *     summary: Update customer group
     *     description: |
     *       Renames a customer group. Implicit `POS` / `Lieferanten` cannot be
     *       renamed (`Name cannot be changed`). Reorder via `PUT /customergroup/order`.
     *     security:
     *       - cookieAuth: []
     *     x-markdown: customergroup/update.md
     *     parameters:
     *       - in: path
     *         name: id
     *         required: true
     *         schema:
     *           type: integer
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             type: object
     *             required: [name]
     *             properties:
     *               name:
     *                 type: string
     *             example:
     *               name: Stammkunden
     *     responses:
     *       200:
     *         description: Updated customer group
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 customergroup:
     *                   $ref: '#/components/schemas/Customergroup'
     *       400:
     *         description: Name required, name cannot be changed, invalid id, or no company selected
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       403:
     *         description: Not authorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Customer group or company not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *   delete:
     *     tags: [Customergroup]
     *     summary: Delete customer group
     *     description: |
     *       Deletes the customer group (cascades entities). Fails with
     *       `Customer group in use` for the POS group or other NO ACTION references.
     *     security:
     *       - cookieAuth: []
     *     x-markdown: customergroup/delete.md
     *     parameters:
     *       - in: path
     *         name: id
     *         required: true
     *         schema:
     *           type: integer
     *     responses:
     *       204:
     *         description: Deleted
     *       400:
     *         description: No company selected or invalid id
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       403:
     *         description: Not authorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Customer group not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       409:
     *         description: Customer group in use
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region PATCH /customergroup/:id

    app.patch(`${basePath}/customergroup/:id`, async (req, res) => {
        const selected = requireSelectedCompany(req);
        if (selected.error) {
            return res.status(400).json({ error: selected.error });
        }

        const id = Number(req.params.id);
        if (!Number.isInteger(id) || id <= 0) {
            return res.status(400).json({ error: 'id is required' });
        }

        const { name } = req.body ?? {};

        try {
            const customergroup = await db.update(req.user.id, id, { name });
            res.status(200).json({ customergroup });
        } catch (error) {
            const status = customergroupErrorStatus(error);
            if (status === 500) console.error('Update customergroup failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    // #region DELETE /customergroup/:id

    app.delete(`${basePath}/customergroup/:id`, async (req, res) => {
        const selected = requireSelectedCompany(req);
        if (selected.error) {
            return res.status(400).json({ error: selected.error });
        }

        const id = Number(req.params.id);
        if (!Number.isInteger(id) || id <= 0) {
            return res.status(400).json({ error: 'id is required' });
        }

        try {
            await db.remove(req.user.id, id);
            res.sendStatus(204);
        } catch (error) {
            const status = customergroupErrorStatus(error);
            if (status === 500) console.error('Delete customergroup failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion
}