import { scalingOwnershipBlocker } from '../autoscaling/ownership.js';
import { fleetSettings } from '../settings.js';
import { randomUUID } from 'node:crypto';
import type { CollectionDetail, CollectionMode, CollectionPreview, CollectionSummary } from '$lib/deployment-plan.js';
import { db } from '../db/index.js';
import { blueprintEntries, summarizeRecipe, type BlueprintEntry } from './launch-recipes.js';
import { creationQueue, destroyServer } from '../provisioning/index.js';
import { deploymentStage, finishDeployment, recordDeploymentEvent } from './deployments.js';
import { housePartyTargets } from './house-party.js';
import { serverObservation } from './status.js';
import { activeBetaRemovalBlocker, getServer } from './servers.js';
import { parseServerName, zombieMapBySlug, zombieMaps } from './map-aliases.js';
import { nativeLaunchSelection, queueNativeCreationIntent } from '../provisioning/native.js';
import { nativeDeployment, nativeInstance } from '../backends/native.js';
import { launchAvailability } from '../hosts/availability.js';

function coverage(entries: BlueprintEntry[], includeHealth = true) {
    type Server = { name: string; game: string | null; map_slug: string | null; map: string | null };
    const registered = db().prepare('SELECT name, game, map_slug, map FROM servers WHERE destroyed_at IS NULL').all() as Server[];
    const queued = db().prepare(`SELECT j.server AS name, substr(j.server, 1, 2) AS game, j.map_slug, j.expected_map AS map
        FROM server_creation_jobs j JOIN server_deployments d ON d.id = j.deployment_id
        WHERE d.server_deleted_at IS NULL AND d.state IN ('queued', 'running', 'awaiting-health')`).all() as Server[];
    const removing = new Set((db().prepare("SELECT server FROM server_deployments WHERE server_deleted_at IS NULL AND action = 'destroy' AND state IN ('waiting', 'running')").all() as { server: string }[]).map(row => row.server));
    // A provisioning server can appear in both tables; count its identity once.
    const servers = [...new Map([...queued, ...registered].map(server => [server.name, server])).values()];
    return entries.map(entry => {
        const existingServers = servers.filter(server => {
            if (removing.has(server.name)) return false;
            const parsed = parseServerName(server.name);
            const game = server.game ?? parsed?.game;
            if (game !== entry.recipe.game) return false;
            if (server.map_slug) return server.map_slug === entry.recipe.mapSlug;
            const namedMap = parsed?.mapCanonical ? zombieMapBySlug(game, parsed.mapSlug) : undefined;
            if (namedMap && (!server.map || server.map === namedMap.canonical)) return namedMap.slug === entry.recipe.mapSlug;
            // Legacy canonical maps are usable only when they identify one variant.
            const matches = zombieMaps(game).filter(map => map.canonical === server.map);
            return matches.length === 1 && matches[0].slug === entry.recipe.mapSlug;
        }).map(server => server.name).sort();
        const coverage = includeHealth ? existingServers.map(name => {
            const operation = db().prepare("SELECT id, state FROM server_deployments WHERE server = ? AND server_deleted_at IS NULL AND action IN ('create','rebuild') AND state IN ('queued', 'running', 'awaiting-health') ORDER BY rowid DESC LIMIT 1").get(name) as { id: string; state: string } | undefined;
            const server = getServer(name);
            return { name, health: operation ? operation.state === 'queued' ? 'queued' : 'starting'
                : server?.container_state && ['stopped', 'exited', 'created', 'dead'].includes(server.container_state) ? 'stopped'
                : server ? serverObservation(server).health : 'offline',
                href: operation ? `/provisioning/${encodeURIComponent(operation.id)}` : `/servers/${encodeURIComponent(name)}` };
        }) : [];
        return { existingServers, coverage, existing: existingServers.length, missing: Math.max(0, entry.count - existingServers.length) };
    });
}

function fleetSnapshot() {
    return housePartyTargets().map(name => ({ name,
        server: db().prepare('SELECT game, map_slug, map, game_port FROM servers WHERE name = ?').get(name) ?? null,
        creation: db().prepare("SELECT id FROM server_deployments WHERE server = ? AND server_deleted_at IS NULL AND action IN ('create','rebuild') ORDER BY rowid DESC LIMIT 1").get(name) ?? null,
        removal: db().prepare("SELECT id FROM server_deployments WHERE server = ? AND server_deleted_at IS NULL AND action = 'destroy' AND state IN ('waiting', 'running')").get(name) ?? null
    }));
}

function collectionPlan(entries: BlueprintEntry[], mode: CollectionMode, includeHealth = true) {
    const counts = coverage(entries, includeHealth);
    // Preserve deployed lobbies before queued ones, then the lowest lobby IDs.
    const retainedServers = counts.flatMap((entry, index) => [...entry.existingServers].sort((a, b) =>
        Number(!!getServer(b)) - Number(!!getServer(a)) || a.localeCompare(b, 'en', { numeric: true })
    ).slice(0, mode === 'exact' ? entries[index].count : undefined));
    const retained = new Set(retainedServers);
    const matching = new Set(counts.flatMap(entry => entry.existingServers));
    const removals = mode === 'exact' ? housePartyTargets().filter(name => !retained.has(name)).map(name => ({ name,
        reason: matching.has(name) ? 'Exceeds the target lobby count' : 'Outside this collection or already awaiting removal'
    })) : [];
    return { counts, retainedServers, removals };
}

function allocate(entries: BlueprintEntry[], counts = coverage(entries)): CollectionPreview['servers'] {
    const occupied = db().prepare(`SELECT name FROM servers UNION
        SELECT j.server AS name FROM server_creation_jobs j JOIN server_deployments d ON d.id=j.deployment_id
        WHERE d.server_deleted_at IS NULL AND (d.state IN ('queued','running','awaiting-health')
            OR (d.action='rebuild' AND (d.state='waiting' OR (d.state IN ('failed','interrupted') AND d.stage='Removing server files and registry'))))`)
        .all() as { name: string }[];
    const lobbies = new Map<string, Set<number>>();
    for (const { name } of occupied) {
        const match = /^(.*)_(\d+)$/.exec(name);
        if (!match) continue;
        const taken = lobbies.get(match[1]) ?? new Set<number>();
        taken.add(Number(match[2])); lobbies.set(match[1], taken);
    }
    const savedKeys = new Set((db().prepare("SELECT server_id FROM server_keys WHERE length(trim(pluto_key))>0").all() as { server_id: string }[]).map(row => row.server_id));
    return entries.flatMap((entry, entryIndex) => Array.from({ length: counts[entryIndex].missing }, () => {
        const base = `${entry.recipe.game}_zombie_${entry.recipe.mapSlug}`;
        const taken = lobbies.get(base) ?? new Set<number>();
        const lobby = Array.from({ length: 20 }, (_, index) => index + 1).find(number => !taken.has(number)) ?? null;
        const name = lobby === null ? null : `${base}_${lobby}`;
        const native = entry.recipe.native;
        const port = null;
        if (lobby !== null) { taken.add(lobby); lobbies.set(base, taken); }
        return { entryIndex, name, port, ...(native ? { native } : {}), hasSavedKey: !!name && savedKeys.has(name) };
    }));
}

function blockersFor(servers: CollectionPreview['servers'], entries: BlueprintEntry[] = []): string[] {
    const blockers: string[] = [];
    for (const server of servers) if (server.name) { const owned = scalingOwnershipBlocker(server.name); if (owned) blockers.push(owned); }
    if (!servers.length) return blockers;
    if (servers.some(server => !server.native && !entries[server.entryIndex]?.recipe.native)) blockers.push('Select and prepare a host before launching.');
    if (servers.some(server => !server.name)) blockers.push('There are not enough free lobbies for one or more maps (20 per map). Reduce their counts or free capacity.');
    return blockers;
}

function removalBlockersFor(removals: CollectionPreview['removals']): string[] {
    const blockers: string[] = [];
    const native = (name: string) => {
        if (nativeInstance(name)) return true;
        const creation = db().prepare(`SELECT id FROM server_deployments WHERE server=? AND server_deleted_at IS NULL
            AND action='create' AND state IN ('queued','running','awaiting-health') ORDER BY rowid DESC LIMIT 1`).get(name) as { id: string } | undefined;
        return !!creation && nativeDeployment(creation.id);
    };
    if (removals.some(server => !native(server.name))) blockers.push('Every server to remove must have a native host instance.');
    for (const server of removals) {
        const owned = scalingOwnershipBlocker(server.name);
        if (owned) blockers.push(owned);
        const blocker = activeBetaRemovalBlocker(server.name);
        if (blocker) blockers.push(blocker);
    }
    return blockers;
}

export function previewCollection(blueprintId: unknown, mode: unknown = 'fill', selection?: Record<string, unknown>): CollectionPreview {
    if (typeof blueprintId !== 'string' || !blueprintId) throw new Error('Choose a collection to launch.');
    if (mode !== 'fill' && mode !== 'exact') throw new Error('Choose fill or exact collection mode.');
    return db().transaction((): CollectionPreview => {
        const { entries, blueprintName } = blueprintEntries(blueprintId);
        const libraries = selection?.libraryIds as Record<string, unknown> | undefined;
        for (const entry of entries) {
            entry.recipe.native = nativeLaunchSelection({ ...selection, libraryId: libraries?.[entry.recipe.game] ?? selection?.libraryId }, entry.recipe.game);
            entry.recipe.image = entry.recipe.native.image!;
        }
        const { counts, retainedServers, removals } = collectionPlan(entries, mode);
        const servers = allocate(entries, counts);
        const blockers = [...blockersFor(servers, entries), ...removalBlockersFor(removals)];
        const selections = servers.flatMap(server => server.native ? [server.native] : []);
        const availability = selections.length ? launchAvailability(selections) : {};
        const id = randomUUID();
        const expiresAt = new Date(Date.now() + 30 * 60_000).toISOString();
        db().prepare('DELETE FROM server_collection_previews WHERE expires_at < ? AND collection_id IS NULL').run(new Date().toISOString());
        db().prepare('INSERT INTO server_collection_previews (id, expires_at, blueprint_name, entries, servers, mode, fleet_snapshot) VALUES (?, ?, ?, ?, ?, ?, ?)')
            .run(id, expiresAt, blueprintName, JSON.stringify(entries), JSON.stringify(servers), mode, mode === 'exact' ? JSON.stringify(fleetSnapshot()) : null);
        return { id, expiresAt, blueprintName, mode, retainedServers, removals, launchConcurrency: fleetSettings().createConcurrency, servers, blockers, ...availability, ready: blockers.length === 0,
            entries: entries.map((entry, index) => ({ count: entry.count, ...counts[index], recipe: summarizeRecipe(entry.recipe) })) };
    })();
}

/** Save all reviewed identities and keys atomically; native placement belongs to provisioning. */
export function queueCollection(input: { previewId?: unknown; keys?: unknown }): { ok: true; collectionId: string | null } {
    if (typeof input.previewId !== 'string' || !input.previewId) throw new Error('Review a collection preview before launching.');
    if (input.keys !== undefined && (!input.keys || typeof input.keys !== 'object' || Array.isArray(input.keys))) throw new Error('Provide keys indexed by the exact server ID.');
    const keys = (input.keys ?? {}) as Record<string, unknown>;
    return db().transaction(() => {
        const preview = db().prepare('SELECT * FROM server_collection_previews WHERE id = ?').get(input.previewId) as {
            id: string; expires_at: string; blueprint_name: string; entries: string; servers: string; collection_id: string | null; mode: CollectionMode; fleet_snapshot: string | null;
        } | undefined;
        if (!preview) throw new Error('Collection preview expired or was not found. Refresh the preview.');
        if (preview.collection_id) return { ok: true as const, collectionId: preview.collection_id };
        if (preview.expires_at <= new Date().toISOString()) throw new Error('Collection preview expired. Refresh it before launching.');
        const entries: BlueprintEntry[] = JSON.parse(preview.entries);
        // Older previews embedded plugin bytes. Queued jobs need only the
        // reviewed metadata; provisioning captures the current files at dispatch.
        for (const entry of entries) entry.recipe.files = entry.recipe.files.map(({ content: _content, ...file }) => file);
        const reviewed: CollectionPreview['servers'] = JSON.parse(preview.servers);
        if (preview.mode === 'exact' && preview.fleet_snapshot !== JSON.stringify(fleetSnapshot())) {
            throw new Error('The fleet changed. Nothing was queued. Refresh the preview and review the servers to keep and remove.');
        }
        const { counts, retainedServers, removals } = collectionPlan(entries, preview.mode, false);
        const servers = reviewed;
        const validatedSelections = new Set<string>();
        for (const server of servers) {
            const recipe = entries[server.entryIndex].recipe;
            const selection = server.native ?? recipe.native;
            if (!selection) throw new Error('Select a native host before launching. Refresh the preview.');
            const identity = JSON.stringify([recipe.game, selection]);
            if (validatedSelections.has(identity)) continue;
            // Recheck saved configuration once per selection without allocating
            // physical capacity or changing the names and files already reviewed.
            nativeLaunchSelection({ ...selection }, recipe.game);
            validatedSelections.add(identity);
        }
        const blockers = [...blockersFor(servers, entries), ...removalBlockersFor(removals)];
        if (blockers.length) throw new Error(blockers.join(' '));
        if (entries.some((_entry, index) => counts[index].missing !== reviewed.filter(server => server.entryIndex === index).length)) {
            throw new Error('Fleet counts changed. Nothing was queued. Refresh the preview and review each server key.');
        }
        const expected = new Set(servers.map(server => server.name));
        for (const [name, value] of Object.entries(keys)) {
            if (!expected.has(name) || typeof value !== 'string') throw new Error('Keys must be strings for server IDs shown in this preview.');
        }
        if (!servers.length && !removals.length) return { ok: true as const, collectionId: null };
        const collectionId = randomUUID();
        db().prepare('INSERT INTO server_launch_collections (id, name, created_at, mode, retained_servers) VALUES (?, ?, ?, ?, ?)')
            .run(collectionId, preview.blueprint_name, new Date().toISOString(), preview.mode, JSON.stringify(retainedServers));
        removals.forEach((server, position) => {
            const queued = db().prepare("SELECT id FROM server_deployments WHERE server = ? AND server_deleted_at IS NULL AND action = 'create' AND state = 'queued'").get(server.name) as { id: string } | undefined;
            let id: string;
            if (queued && !getServer(server.name)) {
                // No container or files exist yet: cancel the reservation instead of booting just to remove it.
                const result = destroyServer(server.name, 'blueprint-exact');
                if (!result.ok) throw new Error(result.message);
                if (!result.deploymentId) throw new Error('Could not queue removal for ' + server.name);
                id = result.deploymentId;
                db().prepare("UPDATE server_deployments SET state = 'cancelled', stage = 'Cancelled by exact collection', finished_at = ? WHERE id = ?").run(new Date().toISOString(), queued.id);
                recordDeploymentEvent(queued.id, 'Queued creation cancelled by exact collection; saved key retained.');
                deploymentStage(id, 'Cancelled queued creation; no server was started');
                finishDeployment(id, { ok: true });
            } else {
                const result = destroyServer(server.name, 'blueprint-exact');
                if (!result.ok) throw new Error(result.message);
                if (!result.deploymentId) throw new Error('Could not queue removal for ' + server.name);
                id = result.deploymentId;
            }
            db().prepare('INSERT INTO server_collection_removals (collection_id, deployment_id, position) VALUES (?, ?, ?)').run(collectionId, id, position);
        });
        servers.forEach((server, index) => {
            const recipe = { ...entries[server.entryIndex].recipe, ...(server.native ? { native: server.native } : {}) };
            if (!recipe.native) throw new Error('Select a native host before launching. Refresh the preview.');
            const result = queueNativeCreationIntent({ server: server.name!, game: recipe.game, mapSlug: recipe.mapSlug,
                selection: recipe.native, recipe, plutoKey: keys[server.name!] as string | undefined, createdBy: 'ui', blueprintName: preview.blueprint_name });
            // Throw so the outer transaction also reverses all earlier keys and children.
            if (!result.ok) throw new Error(`${server.name}: ${result.message} Nothing was queued.`);
            db().prepare('INSERT INTO server_collection_members (collection_id, deployment_id, position) VALUES (?, ?, ?)')
                .run(collectionId, result.deploymentId, index);

        });
        db().prepare('UPDATE server_collection_previews SET collection_id = ? WHERE id = ?').run(collectionId, preview.id);
        return { ok: true as const, collectionId };
    })();
}

const membershipSql = `SELECT collection_id, deployment_id, position FROM server_collection_members
    UNION ALL SELECT collection_id, deployment_id, position FROM server_collection_removals`;

const summarySql = `SELECT c.id, c.name, c.created_at, c.mode, COUNT(d.id) AS total,
    COALESCE(SUM(d.state IN ('done', 'warning')), 0) AS done,
    COALESCE(SUM(d.state IN ('failed', 'interrupted', 'cancelled')), 0) AS failed,
    COALESCE(SUM(d.state IN ('queued', 'running', 'awaiting-health', 'waiting')), 0) AS active,
    COALESCE(SUM(d.state IN ('queued', 'waiting')), 0) AS queued,
    COALESCE(SUM(d.state = 'running'), 0) AS provisioning,
    COALESCE(SUM(d.state = 'awaiting-health'), 0) AS verifying
    FROM server_launch_collections c
    LEFT JOIN (${membershipSql}) m ON m.collection_id = c.id
    LEFT JOIN server_deployments d ON d.id = m.deployment_id`;

export function listCollections(): CollectionSummary[] {
    return db().prepare(summarySql + ' GROUP BY c.id ORDER BY c.created_at DESC, c.rowid DESC').all() as CollectionSummary[];
}

export function getCollection(id: string): CollectionDetail | null {
    const collection = db().prepare(summarySql + ' WHERE c.id = ? GROUP BY c.id').get(id) as CollectionSummary | undefined;
    if (!collection) return null;
    const servers = db().prepare(`SELECT d.id, d.server, d.server_deleted_at, d.action, d.state, d.stage, d.started_at, d.finished_at, d.error, j.port, j.map_slug,
        (d.server_deleted_at IS NULL AND EXISTS(SELECT 1 FROM servers s WHERE s.name = d.server AND s.destroyed_at IS NULL)) AS server_exists
        FROM (${membershipSql}) m JOIN server_deployments d ON d.id = m.deployment_id
        LEFT JOIN server_creation_jobs j ON j.deployment_id = d.id WHERE m.collection_id = ? ORDER BY d.action DESC, m.position`).all(id) as CollectionDetail['servers'];
    const queue = creationQueue();
    const positions = new Map(queue.queued.map((job, index) => [job.id, index + 1]));
    const stored = db().prepare('SELECT retained_servers, retained_server_deletions FROM server_launch_collections WHERE id = ?').get(id) as { retained_servers: string; retained_server_deletions: string };
    return { collection, retainedServers: JSON.parse(stored.retained_servers), retainedServerDeletedAt: JSON.parse(stored.retained_server_deletions), queue: { concurrency: fleetSettings().createConcurrency, active: queue.active, queued: queue.queued.length },
        servers: servers.map(server => ({ ...server, queuePosition: positions.get(server.id) ?? null })) };
}