import fs from 'fs';
import { formatJiraRichText } from './jiraRichText.js';

const SKIP_FIELD_IDS = new Set(['attachment']);
const EASTERN_TIME_ZONE = 'America/New_York';

export function formatEasternDateTime(value) {
    const date = new Date(value);
    if (Number.isNaN(date.getTime())) {
        return String(value);
    }

    const formatted = new Intl.DateTimeFormat('en-US', {
        timeZone: EASTERN_TIME_ZONE,
        month: 'numeric',
        day: 'numeric',
        year: 'numeric',
        hour: 'numeric',
        minute: '2-digit',
        second: '2-digit',
        hour12: true,
    }).format(date);

    const timeZoneName = new Intl.DateTimeFormat('en-US', {
        timeZone: EASTERN_TIME_ZONE,
        timeZoneName: 'short',
    }).formatToParts(date).find(part => part.type === 'timeZoneName')?.value || 'ET';

    return `${formatted} ${timeZoneName}`;
}

export function formatEasternDate(value) {
    const date = new Date(value);
    if (Number.isNaN(date.getTime())) {
        return String(value);
    }

    return new Intl.DateTimeFormat('en-US', {
        timeZone: EASTERN_TIME_ZONE,
        month: 'numeric',
        day: 'numeric',
        year: 'numeric',
    }).format(date);
}

export function loadRequestTypeFields() {
    const path = './config/requestTypeFields.json';
    if (!fs.existsSync(path)) {
        return { common: { displayFields: [] }, groups: {}, requestTypes: {} };
    }
    return JSON.parse(fs.readFileSync(path, 'utf8'));
}

function resolveFieldEntry(entry, groups) {
    if (typeof entry === 'string' && groups[entry]) {
        return groups[entry].displayFields || [];
    }
    return [entry];
}

export function getDisplayFieldsForRequestType(requestTypeId, fieldMap = loadRequestTypeFields()) {
    const key = String(requestTypeId);
    const typeConfig = fieldMap.requestTypes?.[key];
    if (!typeConfig) {
        return fieldMap.common?.displayFields || [];
    }

    const groups = fieldMap.groups || {};
    const resolved = [];

    if (typeConfig.includeCommon !== false) {
        resolved.push(...(fieldMap.common?.displayFields || []));
    }

    for (const groupRef of typeConfig.groups || []) {
        const groupFields = groups[groupRef]?.displayFields || [];
        resolved.push(...groupFields);
    }

    for (const field of typeConfig.displayFields || []) {
        resolved.push(...resolveFieldEntry(field, groups));
    }

    const seen = new Set();
    return resolved.filter(field => {
        const dedupeKey = field.path || field.fieldId;
        if (!dedupeKey || seen.has(dedupeKey) || SKIP_FIELD_IDS.has(field.fieldId)) {
            return false;
        }
        seen.add(dedupeKey);
        return true;
    });
}

export function formatFieldValue(value, format) {
    if (value == null || value === '') {
        return null;
    }

    switch (format) {
        case 'option':
            return value.value ?? value.name ?? String(value);
        case 'user':
            return value.displayName ?? value.emailAddress ?? String(value);
        case 'users':
            if (!Array.isArray(value)) {
                return formatFieldValue(value, 'user');
            }
            return value.map(item => formatFieldValue(item, 'user')).filter(Boolean).join(', ');
        case 'datetime':
            return formatEasternDateTime(value);
        case 'date':
            return formatEasternDate(value);
        case 'cmdb':
            if (Array.isArray(value)) {
                return value.map(item => item.label || item.name || item.objectKey || item.value).filter(Boolean).join(', ');
            }
            return value.label || value.name || value.objectKey || String(value);
        case 'multiselect':
        case 'multicheckboxes':
            if (!Array.isArray(value)) {
                return String(value);
            }
            return value.map(item => item.value || item.label || String(item)).join(', ');
        case 'cascading':
            if (value.child) {
                return `${value.value} → ${value.child.value}`;
            }
            return value.value ?? String(value);
        case 'textarea':
        case 'text':
        default:
            if (typeof value === 'object') {
                const richText = formatJiraRichText(value);
                return richText || value.displayName || value.value || value.name || null;
            }
            return formatJiraRichText(value) || null;
    }
}

export function getFieldValueFromTicket(jiraTicket, fieldDef) {
    if (fieldDef.path) {
        return fieldDef.path.split('.').reduce((current, part) => current?.[part], jiraTicket);
    }

    const fieldId = fieldDef.fieldId;
    if (!fieldId) {
        return null;
    }

    if (fieldId === 'summary' || fieldId === 'description' || fieldId === 'priority' || fieldId === 'created' || fieldId === 'updated') {
        const fields = jiraTicket.issue?.fields || {};
        return fields[fieldId];
    }

    return jiraTicket.issue?.fields?.[fieldId] ?? null;
}

export function buildDetailLinesForRequestType(jiraTicket, requestTypeId, fieldMap = loadRequestTypeFields()) {
    const fields = getDisplayFieldsForRequestType(requestTypeId, fieldMap);
    const lines = [];

    for (const fieldDef of fields) {
        const rawValue = getFieldValueFromTicket(jiraTicket, fieldDef);
        const formatted = formatFieldValue(rawValue, fieldDef.format);
        if (formatted) {
            lines.push({ label: fieldDef.label, value: formatted, format: fieldDef.format });
        }
    }

    return lines;
}