import { validateObjects } from 'react-canvas-label-editor';
import * as db from '../../db/labeltemplate.js';
import { renderThumb } from '../../services/labelThumb.js';
import { emit } from '../sse.js';

// #region Helpers

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

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

function labeltemplateErrorStatus(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 === 'Label template not found') return 404;
    if (error.message === 'Name required') return 400;
    if (error.message === 'Invalid width') return 400;
    if (error.message === 'Invalid height') return 400;
    if (error.message?.startsWith('Invalid dpi')) return 400;
    if (error.message?.startsWith('Invalid type')) return 400;
    if (error.message === 'Content required') return 400;
    if (error.message?.startsWith('Invalid label objects')) return 400;
    return 500;
}

// #endregion

/**
 * Registers label template routes for the authenticated user's selected company.
 * @param {import('express').Application} app
 * @param {string} [basePath='']
 */
export function register(app, basePath = '') {
    /**
     * @openapi
     * /labeltemplate:
     *   get:
     *     tags: [LabelTemplate]
     *     summary: List label templates
     *     description: Lists all ZPL label templates for the selected company. The `thumb` field is returned as a base64-encoded PNG string when present. The `content` field is omitted to reduce payload size (use GET /labeltemplate/{id} for it).
     *     security:
     *       - cookieAuth: []
     *     x-markdown: labeltemplate/list.md
     *     responses:
     *       200:
     *         description: List of label templates
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 labeltemplates:
     *                   type: array
     *                   items:
     *                     $ref: '#/components/schemas/LabelTemplateSummary'
     *       400:
     *         description: No company selected
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region GET /labeltemplate

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

        try {
            const templates = await db.list(req.user.id);
            res.status(200).json({ labeltemplates: templates.map((t) => {
                const { content, ...rest } = serializeTemplate(t);
                return rest;
            }) });
        } catch (error) {
            const status = labeltemplateErrorStatus(error);
            if (status === 500) console.error('List label templates failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    /**
     * @openapi
     * /labeltemplate/{id}:
     *   get:
     *     tags: [LabelTemplate]
     *     summary: Get label template by ID
     *     description: Retrieves a single label template for the authenticated user's selected company.
     *     security:
     *       - cookieAuth: []
     *     x-markdown: labeltemplate/get.md
     *     parameters:
     *       - in: path
     *         name: id
     *         required: true
     *         schema:
     *           type: integer
     *         description: Label template ID
     *     responses:
     *       200:
     *         description: Label template details
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 labeltemplate:
     *                   $ref: '#/components/schemas/LabelTemplate'
     *       400:
     *         description: 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'
     *       404:
     *         description: Label template not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region GET /labeltemplate/:id

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

        const parsedId = parsePositiveInt(req.params.id, 'id');
        if (parsedId.error) {
            return res.status(400).json({ error: parsedId.error });
        }

        try {
            const template = await db.getById(req.user.id, parsedId.id);
            if (!template) {
                return res.status(404).json({ error: 'Label template not found' });
            }
            res.status(200).json({ labeltemplate: serializeTemplate(template) });
        } catch (error) {
            const status = labeltemplateErrorStatus(error);
            if (status === 500) console.error('Get label template failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    /**
     * @openapi
     * /labeltemplate:
     *   post:
     *     tags: [LabelTemplate]
     *     summary: Create label template
     *     description: |
     *       Creates a new ZPL label template for the selected company.
     *       A 50×50 1-bit PNG thumbnail is automatically rendered from the content
     *       and stored with the template.
     *     security:
     *       - cookieAuth: []
     *     x-signals: [labeltemplate]
     *     x-markdown: labeltemplate/create.md
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             $ref: '#/components/schemas/LabelTemplateCreateInput'
     *     responses:
     *       201:
     *         description: Created label template
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 labeltemplate:
     *                   $ref: '#/components/schemas/LabelTemplate'
     *       400:
     *         description: Invalid input or missing fields
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region POST /labeltemplate

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

        const { name, width, height, dpi, type, content } = req.body ?? {};

        const validation = validateLabelContent(content);
        if (!validation.valid) {
            return res.status(400).json({ error: validation.error, ...(validation.errors ? { errors: validation.errors } : {}) });
        }

        try {
            const thumb = await buildThumb({ width, height, content, objects: validation.objects });
            const template = await db.create(req.user.id, {
                name,
                width,
                height,
                dpi,
                type,
                content,
                thumb,
            });
            emit('labeltemplate', { companyId: selected.companyId });
            res.status(201).json({ labeltemplate: serializeTemplate(template) });
        } catch (error) {
            const status = labeltemplateErrorStatus(error);
            if (status === 500) console.error('Create label template failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion

    async function handleUpdate(req, res) {
        const selected = requireSelectedCompany(req);
        if (selected.error) {
            return res.status(400).json({ error: selected.error });
        }

        const parsedId = parsePositiveInt(req.params.id, 'id');
        if (parsedId.error) {
            return res.status(400).json({ error: parsedId.error });
        }

        const { name, width, height, dpi, type, content } = req.body ?? {};

        let validatedObjects;
        if (content !== undefined) {
            const validation = validateLabelContent(content);
            if (!validation.valid) {
                return res.status(400).json({ error: validation.error, ...(validation.errors ? { errors: validation.errors } : {}) });
            }
            validatedObjects = validation.objects;
        }

        try {
            // Re-render thumb whenever content/dimensions are provided
            const thumb = await buildThumb({ width, height, content, objects: validatedObjects });
            const template = await db.update(req.user.id, parsedId.id, {
                name,
                width,
                height,
                dpi,
                type,
                content,
                ...(thumb !== null ? { thumb } : {}),
            });
            emit('labeltemplate', { companyId: selected.companyId });
            res.status(200).json({ labeltemplate: serializeTemplate(template) });
        } catch (error) {
            const status = labeltemplateErrorStatus(error);
            if (status === 500) console.error('Update label template failed:', error);
            res.status(status).json({ error: error.message });
        }
    }

    /**
     * @openapi
     * /labeltemplate/{id}:
     *   patch:
     *     tags: [LabelTemplate]
     *     summary: Update label template (partial)
     *     description: |
     *       Updates specified fields of an existing label template.
     *       When `content` (or `width`/`height`) is provided, the thumbnail is automatically re-rendered.
     *     security:
     *       - cookieAuth: []
     *     x-signals: [labeltemplate]
     *     x-markdown: labeltemplate/update.md
     *     parameters:
     *       - in: path
     *         name: id
     *         required: true
     *         schema:
     *           type: integer
     *         description: Label template ID
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             $ref: '#/components/schemas/LabelTemplateUpdateInput'
     *     responses:
     *       200:
     *         description: Updated label template
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 labeltemplate:
     *                   $ref: '#/components/schemas/LabelTemplate'
     *       400:
     *         description: Invalid input
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Label template not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *   put:
     *     tags: [LabelTemplate]
     *     summary: Update label template
     *     description: |
     *       Replaces an existing label template.
     *       When `content` (or `width`/`height`) is provided, the thumbnail is automatically re-rendered.
     *     security:
     *       - cookieAuth: []
     *     x-signals: [labeltemplate]
     *     x-markdown: labeltemplate/update.md
     *     parameters:
     *       - in: path
     *         name: id
     *         required: true
     *         schema:
     *           type: integer
     *         description: Label template ID
     *     requestBody:
     *       required: true
     *       content:
     *         application/json:
     *           schema:
     *             $ref: '#/components/schemas/LabelTemplateUpdateInput'
     *     responses:
     *       200:
     *         description: Updated label template
     *         content:
     *           application/json:
     *             schema:
     *               type: object
     *               properties:
     *                 labeltemplate:
     *                   $ref: '#/components/schemas/LabelTemplate'
     *       400:
     *         description: Invalid input
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       401:
     *         description: Unauthorized
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     *       404:
     *         description: Label template not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region PATCH /labeltemplate/:id

    app.patch(`${basePath}/labeltemplate/:id`, handleUpdate);

    // #endregion

    // #region PUT /labeltemplate/:id

    app.put(`${basePath}/labeltemplate/:id`, handleUpdate);

    // #endregion

    /**
     * @openapi
     * /labeltemplate/{id}:
     *   delete:
     *     tags: [LabelTemplate]
     *     summary: Delete label template
     *     description: Deletes a label template for the authenticated user's selected company.
     *     security:
     *       - cookieAuth: []
     *     x-signals: [labeltemplate]
     *     x-markdown: labeltemplate/delete.md
     *     parameters:
     *       - in: path
     *         name: id
     *         required: true
     *         schema:
     *           type: integer
     *         description: Label template ID
     *     responses:
     *       204:
     *         description: Label template deleted
     *       400:
     *         description: 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'
     *       404:
     *         description: Label template not found
     *         content:
     *           application/json:
     *             schema:
     *               $ref: '#/components/schemas/Error'
     */
    // #region DELETE /labeltemplate/:id

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

        const parsedId = parsePositiveInt(req.params.id, 'id');
        if (parsedId.error) {
            return res.status(400).json({ error: parsedId.error });
        }

        try {
            await db.remove(req.user.id, parsedId.id);
            emit('labeltemplate', { companyId: selected.companyId });
            res.sendStatus(204);
        } catch (error) {
            const status = labeltemplateErrorStatus(error);
            if (status === 500) console.error('Delete label template failed:', error);
            res.status(status).json({ error: error.message });
        }
    });

    // #endregion
}

/**
 * Serializes a label template row for the API response.
 * Converts the thumb Buffer to a base64 string (or null).
 */
function serializeTemplate(template) {
    return {
        ...template,
        thumb: template.thumb
            ? template.thumb.toString('base64')
            : null,
    };
}

/**
 * Validates the label template content and its objects.
 * Expects content to be an object with an `objects` array (or an array of objects).
 *
 * @param {any} content
 * @returns {{ valid: true, objects: Array } | { valid: false, error: string, errors?: string[] }}
 */
function validateLabelContent(content) {
    if (content == null) {
        return { valid: false, error: 'Content required' };
    }

    let parsed = content;
    if (typeof content === 'string') {
        try {
            parsed = JSON.parse(content);
        } catch {
            return { valid: false, error: 'Invalid JSON in content' };
        }
    }

    const objects = Array.isArray(parsed?.objects)
        ? parsed.objects
        : Array.isArray(parsed)
            ? parsed
            : null;

    if (!objects) {
        return { valid: false, error: 'content.objects must be an array' };
    }

    const { valid, errors } = validateObjects(objects);
    if (!valid) {
        return { valid: false, error: `Invalid label objects: ${errors.join(', ')}`, errors };
    }

    return { valid: true, objects };
}

/**
 * Attempts to render a thumbnail from content + dimensions.
 * Returns null silently if content or dimensions are missing/invalid —
 * the store will reject the request with a proper error anyway.
 *
 * @returns {Promise<Buffer|null>}
 */
async function buildThumb({ width, height, content, objects: passedObjects }) {
    try {
        if (content == null && passedObjects == null) return null;
        const w = Number(width);
        const h = Number(height);
        if (!Number.isInteger(w) || w <= 0 || !Number.isInteger(h) || h <= 0) return null;

        const objects = passedObjects ?? (
            Array.isArray(content?.objects)
                ? content.objects
                : Array.isArray(content)
                    ? content
                    : []
        );

        return await renderThumb({ width: w, height: h, objects });
    } catch {
        // Thumbnail rendering failure is non-fatal
        return null;
    }
}