// routes/ivantiFpWorkflow.js
const express = require('express');
const multer = require('multer');
const path = require('path');
const { requireGroup } = require('../middleware/auth');
const { ivantiFormPost } = require('../helpers/ivantiApi');
const logAudit = require('../helpers/auditLog');

// ---------------------------------------------------------------------------
// Pure helpers (exported for testing)
// ---------------------------------------------------------------------------

const ALLOWED_EXTENSIONS = new Set([
    '.pdf', '.png', '.jpg', '.jpeg', '.gif',
    '.doc', '.docx', '.xlsx', '.csv', '.txt', '.zip'
]);

/**
 * Returns true if the filename has an allowed extension (case-insensitive).
 */
function isAllowedFileExtension(filename) {
    if (!filename || typeof filename !== 'string') return false;
    const ext = path.extname(filename).toLowerCase();
    return ALLOWED_EXTENSIONS.has(ext);
}

/**
 * Validates the FP workflow form body.
 * Returns {} if valid, or { fieldName: 'error message' } for each invalid field.
 */
function validateFpWorkflowForm(body) {
    const errors = {};

    // name: required, non-empty, max 255
    if (!body.name || typeof body.name !== 'string' || body.name.trim().length === 0) {
        errors.name = 'Workflow name is required.';
    } else if (body.name.trim().length > 255) {
        errors.name = 'Workflow name must be 255 characters or fewer.';
    }

    // reason: required, non-empty
    if (!body.reason || typeof body.reason !== 'string' || body.reason.trim().length === 0) {
        errors.reason = 'Reason is required.';
    }

    // description: optional, max 2000 if provided
    if (body.description !== undefined && body.description !== null && body.description !== '') {
        if (typeof body.description !== 'string') {
            errors.description = 'Description must be a string.';
        } else if (body.description.length > 2000) {
            errors.description = 'Description must be 2000 characters or fewer.';
        }
    }

    // expirationDate: required, valid date, strictly after today
    if (!body.expirationDate || typeof body.expirationDate !== 'string' || body.expirationDate.trim().length === 0) {
        errors.expirationDate = 'Expiration date is required.';
    } else {
        const parsed = new Date(body.expirationDate);
        if (isNaN(parsed.getTime())) {
            errors.expirationDate = 'Expiration date must be a valid date.';
        } else {
            const today = new Date();
            today.setHours(0, 0, 0, 0);
            const expDay = new Date(parsed);
            expDay.setHours(0, 0, 0, 0);
            if (expDay <= today) {
                errors.expirationDate = 'Expiration date must be in the future.';
            }
        }
    }

    return errors;
}

/**
 * Builds the subjectFilterRequest JSON for the Ivanti FP workflow endpoint.
 * Format: { subject, filterRequest: { filters } }
 */
function buildSubjectFilterRequest(findingIds) {
    return JSON.stringify({
        subject: 'hostFinding',
        filterRequest: {
            filters: [{
                field: 'id',
                exclusive: false,
                operator: 'IN',
                value: findingIds.map(id => String(id)).join(',')
            }]
        }
    });
}

/**
 * Builds the multipart form fields array for the Ivanti FP workflow request.
 */
function buildIvantiFormFields(formData, findingIds) {
    const scopeMap = {
        'Authorized': 'AUTHORIZED',
        'None': 'NONE',
        'Automated': 'AUTOMATED'
    };

    return [
        { name: 'name', value: formData.name },
        { name: 'reason', value: formData.reason },
        { name: 'description', value: formData.description || '' },
        { name: 'expirationDate', value: formData.expirationDate },
        { name: 'overrideControl', value: scopeMap[formData.scopeOverride] || 'AUTHORIZED' },
        { name: 'subjectFilterRequest', value: buildSubjectFilterRequest(findingIds) },
        { name: 'isEmptyWorkflow', value: findingIds.length === 0 ? 'true' : 'false' }
    ];
}

// ---------------------------------------------------------------------------
// Multer configuration
// ---------------------------------------------------------------------------

const uploadStorage = multer.memoryStorage();

const fpUpload = multer({
    storage: uploadStorage,
    limits: { fileSize: 10 * 1024 * 1024 }, // 10 MB per file
    fileFilter: (req, file, cb) => {
        if (isAllowedFileExtension(file.originalname)) {
            cb(null, true);
        } else {
            cb(new Error(`File type not allowed: ${path.extname(file.originalname)}`));
        }
    }
}).array('attachments', 10); // up to 10 files

// ---------------------------------------------------------------------------
// Router factory
// ---------------------------------------------------------------------------

function createIvantiFpWorkflowRouter(db, requireAuth) {
    const router = express.Router();

    /**
     * POST /api/ivanti/fp-workflow
     *
     * Creates a False Positive workflow batch in the Ivanti/RiskSense API,
     * optionally uploads file attachments, records the submission locally,
     * and marks the associated queue items as complete.
     *
     * Content-Type: multipart/form-data
     *
     * @param {string}   req.body.name            - Workflow name (required, max 255 chars)
     * @param {string}   req.body.reason          - Reason for the FP determination (required)
     * @param {string}   [req.body.description]   - Additional description (optional, max 2000 chars)
     * @param {string}   req.body.expirationDate  - ISO date string, must be a future date (required)
     * @param {string}   [req.body.scopeOverride] - "Authorized" (default) or "None"
     * @param {string}   req.body.findingIds      - JSON-encoded array of Ivanti finding IDs
     * @param {string}   req.body.queueItemIds    - JSON-encoded array of local queue item IDs
     * @param {File[]}   [req.files]              - Up to 10 file attachments (max 10 MB each);
     *                                              allowed extensions: .pdf .png .jpg .jpeg .gif
     *                                              .doc .docx .xlsx .csv .txt .zip
     *
     * @returns {object} 200 - Success
     *   { success: true, workflowBatchId: number, generatedId: string,
     *     attachmentResults: Array<{ filename: string, success: boolean, error?: string }>,
     *     queueItemsUpdated: number, status: 'success' | 'partial' }
     * @returns {object} 400 - Validation error
     *   { error: string } or { success: false, errors: { [field]: string } }
     * @returns {object} 403 - Queue item ownership violation
     *   { error: string }
     * @returns {object} 429 - Ivanti rate limit
     *   { success: false, error: string, step: 'create_workflow' }
     * @returns {object} 500 - Server configuration error
     *   { success: false, error: string, step: 'create_workflow' }
     * @returns {object} 502 - Ivanti API error
     *   { success: false, error: string, step: 'create_workflow', details?: string }
     */
    router.post('/', requireAuth(db), requireGroup('Admin', 'Standard_User'), (req, res) => {
        fpUpload(req, res, (multerErr) => {
            if (multerErr) {
                if (multerErr.code === 'LIMIT_FILE_SIZE') {
                    return res.status(400).json({ error: 'File exceeds the 10 MB size limit.' });
                }
                return res.status(400).json({ error: multerErr.message });
            }

            // --- Parse JSON-encoded arrays from the multipart body ---
            let findingIds, queueItemIds;
            try {
                findingIds = JSON.parse(req.body.findingIds || '[]');
                queueItemIds = JSON.parse(req.body.queueItemIds || '[]');
            } catch (e) {
                return res.status(400).json({ error: 'findingIds and queueItemIds must be valid JSON arrays.' });
            }

            if (!Array.isArray(findingIds) || findingIds.length === 0) {
                return res.status(400).json({ error: 'At least one finding ID is required.' });
            }
            if (!Array.isArray(queueItemIds) || queueItemIds.length === 0) {
                return res.status(400).json({ error: 'At least one queue item ID is required.' });
            }

            // --- Validate form fields ---
            const validationErrors = validateFpWorkflowForm(req.body);
            if (Object.keys(validationErrors).length > 0) {
                return res.status(400).json({ success: false, errors: validationErrors });
            }

            // --- Validate file extensions (belt-and-suspenders with Multer filter) ---
            const files = req.files || [];
            for (const file of files) {
                if (!isAllowedFileExtension(file.originalname)) {
                    return res.status(400).json({
                        error: `File type not allowed: ${file.originalname}. Allowed: ${[...ALLOWED_EXTENSIONS].join(', ')}`
                    });
                }
            }

            // --- Verify queue items belong to user, are FP type, and pending ---
            const placeholders = queueItemIds.map(() => '?').join(',');
            db.all(
                `SELECT id, workflow_type, status, user_id
                 FROM ivanti_todo_queue
                 WHERE id IN (${placeholders})`,
                queueItemIds,
                (err, rows) => {
                    if (err) {
                        console.error('Error verifying queue items:', err);
                        return res.status(500).json({ error: 'Internal server error.' });
                    }

                    // Check all items were found
                    if (!rows || rows.length !== queueItemIds.length) {
                        return res.status(400).json({ error: 'One or more queue items not found.' });
                    }

                    // Check ownership, type, and status
                    for (const row of rows) {
                        if (row.user_id !== req.user.id) {
                            return res.status(403).json({ error: 'You can only submit your own queue items.' });
                        }
                        if (row.workflow_type !== 'FP') {
                            return res.status(400).json({ error: `Queue item ${row.id} is not an FP workflow type.` });
                        }
                        if (row.status !== 'pending') {
                            return res.status(400).json({ error: `Queue item ${row.id} is not in pending status.` });
                        }
                    }

                    // --- Validation passed — submit to Ivanti API ---
                    (async () => {
                        const apiKey = process.env.IVANTI_API_KEY;
                        const clientId = process.env.IVANTI_CLIENT_ID || '1550';
                        const skipTls = process.env.IVANTI_SKIP_TLS === 'true';

                        if (!apiKey) {
                            return res.status(500).json({ success: false, error: 'Ivanti API key is not configured.', step: 'create_workflow' });
                        }

                        // 1. Build form fields and call Ivanti API (multipart/form-data)
                        const formFields = buildIvantiFormFields(req.body, findingIds);
                        const formFiles = files.map(f => ({ name: 'files', buffer: f.buffer, filename: f.originalname }));
                        const createUrl = `/client/${encodeURIComponent(clientId)}/workflowBatch/falsePositive/request`;

                        let createResult;
                        try {
                            createResult = await ivantiFormPost(createUrl, formFields, formFiles, apiKey, skipTls);
                        } catch (networkErr) {
                            logAudit(db, {
                                userId: req.user.id, username: req.user.username,
                                action: 'ivanti_fp_workflow_failed', entityType: 'ivanti_workflow',
                                details: { error: networkErr.message, findingIds },
                                ipAddress: req.ip
                            });
                            return res.status(502).json({ success: false, error: 'Failed to connect to Ivanti API.', step: 'create_workflow', details: networkErr.message });
                        }

                        // Handle error responses from Ivanti
                        if (createResult.status !== 200 && createResult.status !== 201) {
                            const errorMap = {
                                401: 'Ivanti API key is invalid or missing.',
                                419: 'API key lacks workflow creation permissions.',
                                429: 'Ivanti API rate limit reached. Please try again in a few minutes.'
                            };
                            const errorMsg = errorMap[createResult.status] || `Workflow creation failed: ${createResult.status}`;
                            const errorResponse = { success: false, error: errorMsg, step: 'create_workflow' };
                            if (!errorMap[createResult.status]) {
                                errorResponse.details = createResult.body;
                            }

                            logAudit(db, {
                                userId: req.user.id, username: req.user.username,
                                action: 'ivanti_fp_workflow_failed', entityType: 'ivanti_workflow',
                                details: { error: errorMsg, status: createResult.status, findingIds },
                                ipAddress: req.ip
                            });

                            return res.status(createResult.status === 429 ? 429 : 502).json(errorResponse);
                        }

                        // 2. Parse workflow batch response — API returns { id, created }
                        let workflowBatchId;
                        try {
                            const createData = JSON.parse(createResult.body);
                            workflowBatchId = createData.id;
                        } catch (parseErr) {
                            logAudit(db, {
                                userId: req.user.id, username: req.user.username,
                                action: 'ivanti_fp_workflow_failed', entityType: 'ivanti_workflow',
                                details: { error: 'Failed to parse Ivanti response', responseBody: createResult.body },
                                ipAddress: req.ip
                            });
                            return res.status(502).json({ success: false, error: 'Failed to parse Ivanti API response.', step: 'create_workflow' });
                        }

                        // 3. Determine submission status (files sent inline, so success if we got here)
                        const status = 'success';

                        // 4. Insert submission record
                        try {
                            await new Promise((resolve, reject) => {
                                db.run(
                                    `INSERT INTO ivanti_fp_submissions (user_id, username, ivanti_workflow_batch_id, ivanti_generated_id, workflow_name, reason, description, expiration_date, scope_override, finding_ids_json, queue_item_ids_json, attachment_count, attachment_results_json, status, error_message)
                                     VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
                                    [
                                        req.user.id,
                                        req.user.username,
                                        workflowBatchId,
                                        null, // generatedId not returned by this endpoint
                                        req.body.name,
                                        req.body.reason,
                                        req.body.description || null,
                                        req.body.expirationDate,
                                        req.body.scopeOverride || 'Authorized',
                                        JSON.stringify(findingIds),
                                        JSON.stringify(queueItemIds),
                                        files.length,
                                        JSON.stringify(files.map(f => ({ filename: f.originalname, success: true }))),
                                        status,
                                        null
                                    ],
                                    (err) => { if (err) reject(err); else resolve(); }
                                );
                            });
                        } catch (dbErr) {
                            console.error('Failed to insert submission record:', dbErr);
                            // Don't fail the response — the Ivanti workflow was created
                        }

                        // 5. Log audit entry
                        logAudit(db, {
                            userId: req.user.id, username: req.user.username,
                            action: 'ivanti_fp_workflow_created', entityType: 'ivanti_workflow',
                            entityId: String(workflowBatchId),
                            details: { workflowName: req.body.name, findingIds, attachmentCount: files.length, status },
                            ipAddress: req.ip
                        });

                        // 6. Mark queue items as complete
                        let queueItemsUpdated = 0;
                        try {
                            const queuePlaceholders = queueItemIds.map(() => '?').join(',');
                            queueItemsUpdated = await new Promise((resolve, reject) => {
                                db.run(
                                    `UPDATE ivanti_todo_queue SET status='complete', updated_at=CURRENT_TIMESTAMP WHERE id IN (${queuePlaceholders}) AND user_id=?`,
                                    [...queueItemIds, req.user.id],
                                    function (err) { if (err) reject(err); else resolve(this.changes); }
                                );
                            });
                        } catch (queueErr) {
                            console.error('Failed to update queue items:', queueErr);
                            // Don't fail — workflow was created
                        }

                        // 7. Return response
                        res.json({
                            success: true,
                            workflowBatchId,
                            queueItemsUpdated,
                            status
                        });
                    })().catch((unexpectedErr) => {
                        console.error('Unexpected error in FP workflow submission:', unexpectedErr);
                        res.status(500).json({ success: false, error: 'Internal server error.' });
                    });
                }
            );
        });
    });

    return router;
}

module.exports = createIvantiFpWorkflowRouter;
module.exports.validateFpWorkflowForm = validateFpWorkflowForm;
module.exports.buildIvantiFormFields = buildIvantiFormFields;
module.exports.buildSubjectFilterRequest = buildSubjectFilterRequest;
module.exports.isAllowedFileExtension = isAllowedFileExtension;