// Die Schnittstelle fuer das Dashboard.
//
// Eine Regel zieht sich durch alles hier: JEDE Antwort sagt, was passiert ist
// — auch die erfolgreiche. Bei Fivemanage hat genau das gefehlt, und das
// Ergebnis waren neunzehn gleichnamige Organisationen, weil ein Knopf ohne
// Rueckmeldung wie ein kaputter Knopf aussieht.

import { Hono } from 'hono'
import type { Context } from 'hono'
import { deleteCookie, getCookie, setCookie } from 'hono/cookie'
import { config } from '../config.js'
import { db, now, pruneSessions, type Media, type Token, type User } from '../db.js'
import {
    SESSION_COOKIE,
    createSession,
    destroySession,
    generateToken,
    hashPassword,
    tokenHash,
    userForSession,
    verifyPassword,
} from '../auth.js'
import { checkPath, deleteFile, publicUrlFor, PathError } from '../storage.js'

type Vars = { user: User }

export const dashRoutes = new Hono<{ Variables: Vars }>()

/** Den JSON-Rumpf lesen — oder null, wenn keiner ankam.
 *
 *  c.req.json() wirft bei kaputtem JSON, und Hono macht daraus einen nackten
 *  "Internal Server Error" ohne ein Wort dazu. Genau diese Sorte Antwort ist
 *  der Grund, warum wir hier neu bauen. */
async function jsonBody<T>(c: Context<any>): Promise<T | null> {
    try {
        return await c.req.json<T>()
    } catch {
        return null
    }
}

const KEIN_JSON = { error: 'Rumpf ist kein gueltiges JSON' } as const

// ---------------------------------------------------------------- Anmeldung

dashRoutes.post('/auth/login', async (c) => {
    const body = await jsonBody<{ username?: string; password?: string }>(c)
    if (!body) return c.json(KEIN_JSON, 400)
    const { username, password } = body

    if (!username || !password) {
        return c.json({ error: 'Benutzername und Passwort noetig' }, 400)
    }

    const user = db.prepare('SELECT * FROM users WHERE username = ?').get(username) as
        | User
        | undefined

    // Bewusst dieselbe Meldung fuer "kein solcher Benutzer" und "falsches
    // Passwort": alles andere verraet, welche Namen es gibt.
    if (!user || !verifyPassword(password, user.password_hash)) {
        return c.json({ error: 'Benutzername oder Passwort stimmt nicht' }, 401)
    }

    const session = createSession(user.id)
    setCookie(c, SESSION_COOKIE, session.id, {
        httpOnly: true,
        secure: !config.dev,
        sameSite: 'Lax',
        path: '/',
        expires: new Date(session.expiresAt),
    })

    return c.json({ user: { id: user.id, username: user.username } })
})

dashRoutes.post('/auth/logout', (c) => {
    const sid = getCookie(c, SESSION_COOKIE)
    if (sid) destroySession(sid)
    deleteCookie(c, SESSION_COOKIE, { path: '/' })
    return c.json({ ok: true })
})

dashRoutes.get('/auth/me', (c) => {
    const user = userForSession(getCookie(c, SESSION_COOKIE))
    if (!user) return c.json({ error: 'nicht angemeldet' }, 401)
    return c.json({ user: { id: user.id, username: user.username } })
})

// Ab hier gilt: angemeldet oder nichts.
dashRoutes.use('*', async (c, next) => {
    const user = userForSession(getCookie(c, SESSION_COOKIE))
    if (!user) return c.json({ error: 'nicht angemeldet' }, 401)
    c.set('user', user)
    await next()
})

dashRoutes.post('/auth/password', async (c) => {
    const body = await jsonBody<{ current?: string; next?: string }>(c)
    if (!body) return c.json(KEIN_JSON, 400)
    const { current, next: fresh } = body
    const user = c.get('user')

    if (!current || !fresh) return c.json({ error: 'beide Passwoerter noetig' }, 400)
    if (fresh.length < 8) return c.json({ error: 'mindestens 8 Zeichen' }, 400)
    if (!verifyPassword(current, user.password_hash)) {
        return c.json({ error: 'aktuelles Passwort stimmt nicht' }, 401)
    }

    db.prepare('UPDATE users SET password_hash = ? WHERE id = ?').run(
        hashPassword(fresh),
        user.id,
    )
    // Alle anderen Sitzungen beenden — ein Passwortwechsel, der alte
    // Anmeldungen weiterlaufen laesst, ist keiner.
    db.prepare('DELETE FROM sessions WHERE user_id = ? AND id != ?').run(
        user.id,
        getCookie(c, SESSION_COOKIE),
    )
    return c.json({ ok: true })
})

// ------------------------------------------------------------------- Medien

dashRoutes.get('/media', (c) => {
    const query = c.req.query('query')?.trim() ?? ''
    const limit = Math.min(Number(c.req.query('limit') ?? 60) || 60, 200)
    const offset = Math.max(Number(c.req.query('offset') ?? 0) || 0, 0)

    const where = query ? 'WHERE path LIKE ?' : ''
    const params = query ? [`%${query}%`] : []

    const total = db.prepare(`SELECT COUNT(*) AS n FROM media ${where}`).get(...params) as {
        n: number
    }
    const rows = db
        .prepare(
            `SELECT * FROM media ${where} ORDER BY updated_at DESC LIMIT ? OFFSET ?`,
        )
        .all(...params, limit, offset) as Media[]

    return c.json({
        total: total.n,
        limit,
        offset,
        items: rows.map((row) => ({ ...row, url: publicUrlFor(row.path) })),
    })
})

dashRoutes.delete('/media/:id', async (c) => {
    const id = Number(c.req.param('id'))
    const row = db.prepare('SELECT * FROM media WHERE id = ?').get(id) as Media | undefined
    if (!row) return c.json({ error: 'nicht gefunden' }, 404)

    await deleteFile(row.path)
    db.prepare('DELETE FROM media WHERE id = ?').run(id)
    return c.json({ deleted: row.path })
})

/** Mehrere auf einmal — bei 900 Fahrzeugbildern will niemand 900 Mal klicken. */
dashRoutes.post('/media/delete', async (c) => {
    const body = await jsonBody<{ ids?: number[] }>(c)
    if (!body) return c.json(KEIN_JSON, 400)
    const { ids } = body
    if (!Array.isArray(ids) || ids.length === 0) {
        return c.json({ error: 'keine Auswahl' }, 400)
    }

    const select = db.prepare('SELECT * FROM media WHERE id = ?')
    const remove = db.prepare('DELETE FROM media WHERE id = ?')
    const deleted: string[] = []

    for (const id of ids) {
        const row = select.get(id) as Media | undefined
        if (!row) continue
        await deleteFile(row.path)
        remove.run(id)
        deleted.push(row.path)
    }

    return c.json({ deleted, count: deleted.length })
})

dashRoutes.get('/stats', (c) => {
    const media = db
        .prepare('SELECT COUNT(*) AS files, COALESCE(SUM(size), 0) AS bytes FROM media')
        .get() as { files: number; bytes: number }
    const tokens = db.prepare('SELECT COUNT(*) AS n FROM tokens').get() as { n: number }

    // Die groessten Ordner — die erste Frage bei "wo ist mein Platz hin".
    const folders = db
        .prepare(
            `SELECT
                 CASE WHEN instr(path, '/') > 0
                      THEN substr(path, 1, instr(path, '/') - 1)
                      ELSE '(Wurzel)' END AS folder,
                 COUNT(*) AS files,
                 SUM(size) AS bytes
             FROM media GROUP BY folder ORDER BY bytes DESC LIMIT 10`,
        )
        .all() as { folder: string; files: number; bytes: number }[]

    return c.json({ ...media, tokens: tokens.n, folders, publicUrl: config.publicUrl })
})

// ------------------------------------------------------------------- Tokens

dashRoutes.get('/tokens', (c) => {
    const rows = db
        .prepare('SELECT id, name, prefix, can_delete, created_at, last_used_at FROM tokens ORDER BY created_at DESC')
        .all() as Omit<Token, 'hash'>[]
    return c.json({ items: rows })
})

dashRoutes.post('/tokens', async (c) => {
    const body = await jsonBody<{
        name?: string
        prefix?: string
        canDelete?: boolean
    }>(c)
    if (!body) return c.json(KEIN_JSON, 400)
    const { name, prefix, canDelete } = body

    if (!name?.trim()) return c.json({ error: 'Name fehlt' }, 400)

    // Das Praefix ist ein Pfadanfang und wird nach denselben Regeln geprueft.
    let cleanPrefix = ''
    if (prefix?.trim()) {
        try {
            cleanPrefix = checkPath(prefix.trim().replace(/\/+$/, ''))
        } catch (err) {
            if (err instanceof PathError) return c.json({ error: err.message }, 400)
            throw err
        }
    }

    const token = generateToken()
    const info = db
        .prepare(
            `INSERT INTO tokens (name, hash, prefix, can_delete, created_at)
             VALUES (?, ?, ?, ?, ?)`,
        )
        .run(name.trim(), tokenHash(token), cleanPrefix, canDelete ? 1 : 0, now())

    // Der Klartext geht genau EINMAL raus. Danach steht nur noch der Hash in
    // der Datenbank, und auch wir koennen ihn nicht mehr zeigen.
    return c.json({
        id: Number(info.lastInsertRowid),
        name: name.trim(),
        prefix: cleanPrefix,
        canDelete: Boolean(canDelete),
        token,
    })
})

dashRoutes.delete('/tokens/:id', (c) => {
    const info = db.prepare('DELETE FROM tokens WHERE id = ?').run(Number(c.req.param('id')))
    if (info.changes === 0) return c.json({ error: 'nicht gefunden' }, 404)
    return c.json({ ok: true })
})

dashRoutes.post('/maintenance/prune-sessions', (c) => {
    pruneSessions()
    return c.json({ ok: true })
})