import { getConfig } from "../common/config.js";
import { getPool } from "../db/index.js";
import { verifyKey } from "../modules/core/apiKey.js";
import crypto from 'crypto';

// Bearer-token auth for the central /api/v1/* API. On success it sets
// req.session.user_id (which the core router scopes queries by). It does NOT
// populate req.user — the browser session routes (passport) own that — so the
// session-authed dashboard/key-management routes remain login-only by design.
export async function apiMiddleware(req, res, next) {
    let success = false;
    try {
        const apiKey = req.headers['authorization']?.split(' ')[1];
        if (apiKey) {
            // Preferred: the hashed multi-key store (with a short in-memory cache).
            const found = await verifyKey(apiKey);
            if (found) {
                req.session.user_id = found.user_id;
                success = true;
            } else {
                // Fallback: the legacy single plaintext key in `auth` (issued at login).
                const client = await getPool();
                try {
                    const r = await client.query(
                        `SELECT au.user_id FROM public.auth au WHERE au.api_key = $1`,
                        [apiKey],
                    );
                    if (r.rowCount > 0) {
                        req.session.user_id = r.rows[0].user_id;
                        success = true;
                    }
                } finally {
                    await client.release();
                }
            }
        }
    } catch (e) {
        console.error(e);
    }
    if (!success)
        return res.status(401).json({ error: 'API key is invalid' });
    next();
}

export function getNewKey(user) {
    const seed = `${user.issuer}:${user.identifier}:${user.id}:${crypto.randomBytes(16).toString('hex')}`;
    const hash = crypto.createHash('sha256').update(seed).digest();
    const apiKey = hash.toString('hex');
    return apiKey;
}

async function createApiKeys(client, user, issuer) {
    const config = getConfig();
    for (const type in config.appModules) {
        // Internal modules (e.g. dashboard) have no `app` row and mint no keys.
        if (config.appModules[type]?.internal) continue;
        const apiKey = issuer !== 'https://single'
            ? getNewKey(user)
            : config.authModules.single[type]
        await client.query(`
            INSERT INTO public.auth (
                user_id,
                app_id,
                api_key
            ) VALUES (
                $1,
                (SELECT id FROM public.app WHERE type = $2),
                $3
            ) ON CONFLICT DO NOTHING;
        `, [
            user.id,
            type,
            apiKey,
        ]);
    }
}

async function checkIfUserExists(client, issuer, identifier) {
    return await client.query(`
        SELECT
            u.id,
            u.photo,
            u.username
        FROM public.user u
        WHERE u.identifier = $1
        AND u.issuer = $2
    `,
    [
        identifier,
        issuer,
    ]);
}

export async function getUser(client, issuer, identifier) {
    const res = await client.query(`
        SELECT
            u.id,
            u.username,
            u.photo,
            u.issuer,
            u.identifier,
            COALESCE(ut.can_view_json, FALSE) AS "canViewJson",
            json_agg(
                jsonb_build_object(
                    'id', a.id,
                    'type', a.type,
                    'apiKey', au.api_key
                )
            ) AS apps
        FROM public.user u
        INNER JOIN public.auth au ON u.id = au.user_id
        INNER JOIN public.app a ON au.app_id = a.id
        LEFT JOIN public.user_type ut ON ut.id = u.user_type_id
        WHERE u.identifier = $1
        AND u.issuer = $2
        GROUP BY
            u.id,
            u.username,
            u.photo,
            u.issuer,
            u.identifier,
            ut.can_view_json
    `,
        [
            identifier,
            issuer,
        ]);
    if (res.rowCount > 0) {
        const user = res.rows[0];
        return user;
    }
    return null;
}

export async function checkUser(type, issuer, identifier, username, photo) {
    const client = await getPool();
    let userExists = await checkIfUserExists(client, issuer, identifier);
    if (userExists.rowCount === 0) {
        if (!username || username === '') {
            username = identifier;
        }
        // New users default to the least-privileged role; an administrator
        // promotes them. Existing users keep whatever the DB already holds
        // (see the 000019 backfill) — checkUser never overwrites an existing type.
        const res = await client.query(`
            INSERT INTO public.user (
                username,
                issuer,
                identifier,
                photo,
                type,
                user_type_id
            ) VALUES (
                $1,
                $2,
                $3,
                $4,
                $5,
                (SELECT id FROM public.user_type WHERE value = 'standard')
            ) RETURNING id;
        `, [
            username,
            issuer,
            identifier,
            photo,
            type,
        ]);
        if (res.rowCount === 0) {
            return null;
        }
        await createApiKeys(client, res.rows[0], issuer);
    } else {
        if (photo !== userExists.rows[0].photo || username != userExists.rows[0].username) {
            await client.query(`
                UPDATE public.user SET
                    photo = $1,
                    username = $2,
                    updated_ts = NOW()
                WHERE id = $3
            `, [
                userExists.rows[0].photo,
                userExists.rows[0].username,
                userExists.rows[0].id,
            ]);
        }
        await createApiKeys(client, userExists.rows[0], issuer);
    }
    const user = await getUser(client, issuer, identifier);
    return user;
}

export async function initModules(app, passport) {
    const config = getConfig();
    for (const authModule of Object.keys(config.authModules)) {
        const authModulePath = `../modules/auth/${authModule}.js`;
        const { initModule } = await import(authModulePath);
        await initModule(app, passport);
    }
}