// Jira issue lifecycle: fetch, search-by-reporter, status, update, transitions,
// close. All project-agnostic (works for any project the token can see) and
// uses the core /rest/api/3/issue/... endpoints.
import logger from '../../utilities/logger.js';
import config from '../../config/index.js';
import { jiraClient, plainTextToAdf } from './client.js';
import { fetchPublicComments } from './comments.js';

const KEY_RE = /^[A-Z]+-\d+$/;

export async function fetchJiraIssue(key) {
    if (!key || !KEY_RE.test(key)) {
        throw new Error(`Invalid ticket key: "${key}"`);
    }

    const url = `/rest/api/3/issue/${key}?fields=summary,status,assignee,created,updated,priority`;
    try {
        const response = await jiraClient.get(url);
        return response.data;
    } catch (error) {
        logger.error('Fetch Jira issue failed:', error.response?.data || error.message);
        throw new Error(`Issue fetch failed: ${error.message}`);
    }
}

export async function fetchPlainDescription(key) {
    const payload = { expression: "issue.description.plainText", context: { issue: { key } } };
    try {
        const response = await jiraClient.post('/rest/api/3/expression/evaluate', payload, {
            headers: { 'Content-Type': 'application/json' }
        });
        return response.data.value || 'No description available.';
    } catch (error) {
        logger.warn('Failed to fetch plain description:', error.message);
        return 'No description available.';
    }
}

// Kept for future use (email → accountId lookup). Not currently called; the
// reporter search uses email directly in JQL.
// eslint-disable-next-line no-unused-vars
async function getAccountIdFromEmail(email) {
    if (!email) {
        throw new Error('Email is required');
    }

    const url = `/rest/api/3/user/search?query=${encodeURIComponent(email)}&maxResults=10`;
    try {
        const response = await jiraClient.get(url);
        const users = response.data || [];

        if (users.length === 0) {
            throw new Error(`No users found matching "${email}"`);
        }

        let user = users.find(u => u.emailAddress?.toLowerCase() === email.toLowerCase());
        if (!user && users.length > 0) {
            user = users[0];
        }

        if (!user?.accountId) {
            throw new Error(`No usable accountId found for "${email}"`);
        }

        logger.info(`Using accountId ${user.accountId} for email "${email}"`);
        return user.accountId;
    } catch (err) {
        throw new Error(`User lookup failed: ${err.message}`);
    }
}

/**
 * Search open tickets reported by a given email (across CS/SS/SUPPORT
 * projects). Enriches each result with plain-text description + last 6
 * public comments so downstream (Grok) has full context in one round trip.
 */
export async function searchOpenTicketsByReporterEmail(email) {
    if (!email || typeof email !== 'string' || email.trim() === '') {
        throw new Error("Email is required");
    }

    const jql = `project in (CS, SS, SUPPORT) 
                 AND reporter = "${email}" 
                 AND statusCategory != Done 
                 ORDER BY updated DESC`;

    try {
        const response = await jiraClient.post('/rest/api/3/search/jql', {
            jql: jql,
            maxResults: 8,
            fields: ["key", "summary", "status", "updated", "description"],
            expand: "comments"
        }, {
            headers: { 'Content-Type': 'application/json' }
        });

        const issues = response.data.issues || [];

        const enrichedIssues = await Promise.all(
            issues.map(async (issue) => {
                const key = issue.key;
                try {
                    const [plainDesc, publicComments] = await Promise.all([
                        fetchPlainDescription(key).catch(() => "No description available."),
                        fetchPublicComments(key).catch(() => [])
                    ]);

                    issue.enrichedNotes = {
                        description: plainDesc,
                        publicComments: publicComments.slice(-6)
                    };
                } catch (err) {
                    logger.warn(`Failed to enrich notes for ${key}:`, err.message);
                    issue.enrichedNotes = { description: "Notes unavailable.", publicComments: [] };
                }
                return issue;
            })
        );

        return enrichedIssues;
    } catch (error) {
        logger.error('Jira reporter search failed:', error.response?.data || error.message);
        throw new Error(`Failed to search tickets reported by ${email}: ${error.message}`);
    }
}

/**
 * Compact, purpose-built status view — no Grok, no comment enrichment.
 * Use this when a caller just wants "where is this ticket right now?".
 */
export async function getTicketStatus(key) {
    if (!key || !KEY_RE.test(key)) {
        throw new Error(`Invalid ticket key: "${key}"`);
    }

    const url = `/rest/api/3/issue/${key}?fields=summary,status,assignee,reporter,priority,resolution,created,updated,labels`;
    try {
        const { data } = await jiraClient.get(url);
        const f = data.fields || {};
        return {
            key: data.key,
            summary: f.summary || null,
            status: f.status?.name || null,
            statusCategory: f.status?.statusCategory?.key || null,
            assignee: f.assignee?.displayName || f.assignee?.emailAddress || null,
            reporter: f.reporter?.displayName || f.reporter?.emailAddress || null,
            priority: f.priority?.name || null,
            resolution: f.resolution?.name || null,
            labels: f.labels || [],
            created: f.created || null,
            updated: f.updated || null
        };
    } catch (err) {
        logger.error('getTicketStatus failed', { key, status: err.response?.status, details: err.response?.data });
        const e = new Error(`Failed to fetch status for ${key}: ${err.message}`);
        e.status = err.response?.status;
        e.details = err.response?.data;
        throw e;
    }
}

/**
 * Partial issue update. Accepts flat, friendly fields:
 *   { summary, description, priority, labels, assigneeAccountId, additional }
 * `additional` is merged raw into the `fields` object (e.g. customfield_*).
 * `description` is a plain string; converted to ADF here.
 */
export async function updateTicket(key, updates = {}) {
    if (!key || !KEY_RE.test(key)) {
        throw new Error(`Invalid ticket key: "${key}"`);
    }

    const fields = {};
    if (updates.summary !== undefined) fields.summary = String(updates.summary);
    if (updates.description !== undefined) fields.description = plainTextToAdf(updates.description);
    if (updates.priority) fields.priority = { name: String(updates.priority) };
    if (Array.isArray(updates.labels)) fields.labels = updates.labels.map(String);
    if (updates.assigneeAccountId) fields.assignee = { accountId: String(updates.assigneeAccountId) };
    if (updates.additional && typeof updates.additional === 'object') Object.assign(fields, updates.additional);

    if (Object.keys(fields).length === 0) {
        throw new Error('updateTicket called with no updatable fields');
    }

    try {
        await jiraClient.put(`/rest/api/3/issue/${key}`, { fields }, {
            headers: { 'Content-Type': 'application/json' }
        });
        logger.info('Ticket updated', { key, fieldKeys: Object.keys(fields) });
        return { key, updated: Object.keys(fields) };
    } catch (err) {
        logger.error('updateTicket failed', { key, status: err.response?.status, details: err.response?.data });
        const e = new Error(err.response?.data?.errorMessages?.join('; ') || err.message);
        e.status = err.response?.status;
        e.details = err.response?.data;
        throw e;
    }
}

/**
 * Fetch available workflow transitions for an issue. Useful for both the
 * client picking a transition manually and for closeTicket() below.
 */
export async function getTransitions(key) {
    if (!key || !KEY_RE.test(key)) {
        throw new Error(`Invalid ticket key: "${key}"`);
    }
    try {
        const { data } = await jiraClient.get(`/rest/api/3/issue/${key}/transitions`);
        return (data.transitions || []).map(t => ({
            id: t.id,
            name: t.name,
            to: { id: t.to?.id, name: t.to?.name, statusCategory: t.to?.statusCategory?.key },
            hasScreen: !!t.hasScreen
        }));
    } catch (err) {
        logger.error('getTransitions failed', { key, status: err.response?.status, details: err.response?.data });
        throw new Error(`Failed to fetch transitions for ${key}: ${err.message}`);
    }
}

/**
 * Execute a specific transition. Optionally set a resolution and/or append a
 * comment in the same call (both are fields the transition screen can accept).
 */
export async function transitionTicket(key, transitionId, { resolution, comment, internal = false, additionalFields } = {}) {
    if (!key || !KEY_RE.test(key)) {
        throw new Error(`Invalid ticket key: "${key}"`);
    }
    if (!transitionId) throw new Error('transitionId is required');

    const payload = { transition: { id: String(transitionId) } };

    const fields = { ...(additionalFields || {}) };
    if (resolution) fields.resolution = { name: String(resolution) };
    if (Object.keys(fields).length) payload.fields = fields;

    if (comment) {
        const commentEntry = { add: { body: plainTextToAdf(String(comment)) } };
        if (internal) {
            commentEntry.add.visibility = { type: 'role', value: config.jira.commentVisibilityRole || 'Service Desk Team' };
        }
        payload.update = { comment: [commentEntry] };
    }

    try {
        await jiraClient.post(`/rest/api/3/issue/${key}/transitions`, payload, {
            headers: { 'Content-Type': 'application/json' }
        });
        logger.info('Ticket transitioned', { key, transitionId, resolution });
        return { key, transitionId, resolution: resolution || null };
    } catch (err) {
        logger.error('transitionTicket failed', {
            key, transitionId, status: err.response?.status, details: err.response?.data
        });
        const e = new Error(err.response?.data?.errorMessages?.join('; ') || err.message);
        e.status = err.response?.status;
        e.details = err.response?.data;
        throw e;
    }
}

/**
 * Convenience: find a "closing" transition and execute it.
 * Prefers explicit `transitionName` if provided, otherwise picks the first
 * transition whose target status is in category "done" (Jira's canonical
 * category for closed/resolved/completed), falling back to a name-based match.
 */
export async function closeTicket(key, { transitionName, resolution = 'Done', comment, internal = false } = {}) {
    const transitions = await getTransitions(key);
    if (transitions.length === 0) {
        throw new Error(`No workflow transitions available for ${key} (check assignee/permissions)`);
    }

    let chosen = null;
    if (transitionName) {
        chosen = transitions.find(t => t.name.toLowerCase() === transitionName.toLowerCase());
        if (!chosen) {
            throw new Error(`Transition "${transitionName}" not available for ${key}. Available: ${transitions.map(t => t.name).join(', ')}`);
        }
    } else {
        chosen = transitions.find(t => t.to?.statusCategory === 'done')
            || transitions.find(t => /done|closed|resolved|complete/i.test(t.name));
        if (!chosen) {
            throw new Error(`Could not find a closing transition for ${key}. Available: ${transitions.map(t => t.name).join(', ')}`);
        }
    }

    return transitionTicket(key, chosen.id, { resolution, comment, internal });
}