// SQLite-Anbindung (better-sqlite3, synchron & schnell) — Schema wird beim Start angelegt
import Database from 'better-sqlite3';
import { mkdirSync, statSync } from 'node:fs';
import { dirname, resolve } from 'node:path';
import { config } from './config.js';

const dbFile = resolve(config.dbPath);
mkdirSync(dirname(dbFile), { recursive: true });

export const db = new Database(dbFile);
db.pragma('journal_mode = WAL');

db.exec(`
    CREATE TABLE IF NOT EXISTS commits (
        sha         TEXT PRIMARY KEY,
        repo        TEXT NOT NULL,
        branch      TEXT NOT NULL,
        message     TEXT NOT NULL,
        author_name TEXT,
        author_user TEXT,
        url         TEXT,
        committed_at TEXT NOT NULL,
        received_at  TEXT NOT NULL DEFAULT (datetime('now'))
    );
    CREATE INDEX IF NOT EXISTS idx_commits_repo_time ON commits (repo, committed_at DESC);

    CREATE TABLE IF NOT EXISTS devlogs (
        message_id  TEXT PRIMARY KEY,
        channel_id  TEXT NOT NULL,
        content     TEXT NOT NULL,
        author_name TEXT,
        posted_at   TEXT NOT NULL,
        archived_at TEXT NOT NULL DEFAULT (datetime('now'))
    );
    CREATE INDEX IF NOT EXISTS idx_devlogs_posted ON devlogs (posted_at DESC);
`);

// Migration: images-Spalte (JSON-Array lokaler Dateinamen) für bestehende DBs
const devlogCols = db.prepare('PRAGMA table_info(devlogs)').all();
if (!devlogCols.some((c) => c.name === 'images')) {
    db.exec(`ALTER TABLE devlogs ADD COLUMN images TEXT NOT NULL DEFAULT '[]'`);
}

// Releases (Gitea-Release-Webhook) — für Ankündigungen + Changelog-Seite
db.exec(`
    CREATE TABLE IF NOT EXISTS releases (
        repo         TEXT NOT NULL,
        tag          TEXT NOT NULL,
        name         TEXT,
        body         TEXT,
        url          TEXT,
        prerelease   INTEGER NOT NULL DEFAULT 0,
        published_at TEXT NOT NULL,
        PRIMARY KEY (repo, tag)
    );
`);

// Volltextsuche (FTS5) über Devlogs — Trigger halten den Index synchron
db.exec(`
    CREATE VIRTUAL TABLE IF NOT EXISTS devlogs_fts USING fts5(content, message_id UNINDEXED);
    CREATE TRIGGER IF NOT EXISTS devlogs_fts_ai AFTER INSERT ON devlogs BEGIN
        INSERT INTO devlogs_fts (rowid, content, message_id)
        VALUES (new.rowid, new.content, new.message_id);
    END;
    CREATE TRIGGER IF NOT EXISTS devlogs_fts_ad AFTER DELETE ON devlogs BEGIN
        DELETE FROM devlogs_fts WHERE rowid = old.rowid;
    END;
`);
// Bestehende Zeilen nachindexieren (einmalig nach der Migration)
{
    const ftsCount = db.prepare('SELECT count(*) AS n FROM devlogs_fts').get().n;
    const devlogCount = db.prepare('SELECT count(*) AS n FROM devlogs').get().n;
    if (ftsCount !== devlogCount) {
        db.exec(`
            DELETE FROM devlogs_fts;
            INSERT INTO devlogs_fts (rowid, content, message_id)
            SELECT rowid, content, message_id FROM devlogs;
        `);
    }
}

// Laufzeit-Einstellungen (Settings-Seite im Webinterface) — überschreiben Env-Defaults
db.exec('CREATE TABLE IF NOT EXISTS settings (key TEXT PRIMARY KEY, value TEXT NOT NULL)');
const getSettingStmt = db.prepare('SELECT value FROM settings WHERE key = ?');
const setSettingStmt = db.prepare(`
    INSERT INTO settings (key, value) VALUES (?, ?)
    ON CONFLICT(key) DO UPDATE SET value = excluded.value
`);

export function getSetting(key) {
    return getSettingStmt.get(key)?.value ?? null;
}

export function setSetting(key, value) {
    setSettingStmt.run(key, value);
}

const insertCommit = db.prepare(`
    INSERT OR IGNORE INTO commits (sha, repo, branch, message, author_name, author_user, url, committed_at)
    VALUES (@sha, @repo, @branch, @message, @author_name, @author_user, @url, @committed_at)
`);

/** Commits eines Pushes speichern — bereits bekannte SHAs werden ignoriert. Gibt Anzahl neuer Zeilen zurück. */
export const saveCommits = db.transaction((commits) => {
    let inserted = 0;
    for (const commit of commits) {
        inserted += insertCommit.run(commit).changes;
    }
    return inserted;
});

const insertDevlog = db.prepare(`
    INSERT OR IGNORE INTO devlogs (message_id, channel_id, content, author_name, posted_at, images)
    VALUES (@message_id, @channel_id, @content, @author_name, @posted_at, @images)
`);
const hasDevlogStmt = db.prepare('SELECT 1 FROM devlogs WHERE message_id = ?');

/** Devlog speichern — bereits bekannte Message-IDs werden ignoriert. Gibt true zurück, wenn neu. */
export function saveDevlog(devlog) {
    return insertDevlog.run({ images: '[]', ...devlog }).changes > 0;
}

/** true, wenn die Message schon archiviert ist (spart z. B. erneute Bild-Downloads) */
export function hasDevlog(messageId) {
    return Boolean(hasDevlogStmt.get(messageId));
}

const getDevlogImagesStmt = db.prepare('SELECT images FROM devlogs WHERE message_id = ?');
const deleteDevlogStmt = db.prepare('DELETE FROM devlogs WHERE message_id = ?');

/** Devlog löschen; gibt { deleted, images } zurück (Dateinamen fürs Aufräumen) */
export function deleteDevlog(messageId) {
    const row = getDevlogImagesStmt.get(messageId);
    if (!row) return { deleted: false, images: [] };
    deleteDevlogStmt.run(messageId);
    return { deleted: true, images: JSON.parse(row.images || '[]') };
}

// --- Lese-Queries für die Web-API (Feature 4) ---

const selectDevlogs = db.prepare(`
    SELECT message_id, content, author_name, posted_at, images
    FROM devlogs ORDER BY posted_at DESC LIMIT ? OFFSET ?
`);
const countDevlogsStmt = db.prepare('SELECT COUNT(*) AS n FROM devlogs');

export function listDevlogs(limit, offset) {
    return { items: selectDevlogs.all(limit, offset), total: countDevlogsStmt.get().n };
}

const searchDevlogsStmt = db.prepare(`
    SELECT d.message_id, d.content, d.author_name, d.posted_at, d.images
    FROM devlogs_fts f
    JOIN devlogs d ON d.rowid = f.rowid
    WHERE devlogs_fts MATCH ?
    ORDER BY d.posted_at DESC LIMIT ? OFFSET ?
`);
const searchDevlogsCountStmt = db.prepare(
    'SELECT count(*) AS n FROM devlogs_fts WHERE devlogs_fts MATCH ?'
);

/** Suchbegriff in eine sichere FTS5-Query übersetzen: jede Eingabe als Präfix-Phrase */
function ftsQuery(input) {
    const terms = input.split(/\s+/).filter(Boolean).slice(0, 8);
    return terms.map((t) => `"${t.replaceAll('"', '')}"*`).join(' ');
}

export function searchDevlogs(input, limit, offset) {
    const query = ftsQuery(input);
    if (!query) return { items: [], total: 0 };
    return {
        items: searchDevlogsStmt.all(query, limit, offset),
        total: searchDevlogsCountStmt.get(query).n,
    };
}

const selectCommits = db.prepare(`
    SELECT sha, repo, branch, message, author_name, url, committed_at
    FROM commits ORDER BY committed_at DESC LIMIT ? OFFSET ?
`);
const countCommitsStmt = db.prepare('SELECT COUNT(*) AS n FROM commits');

export function listCommits(limit, offset) {
    return { items: selectCommits.all(limit, offset), total: countCommitsStmt.get().n };
}

const upsertRelease = db.prepare(`
    INSERT INTO releases (repo, tag, name, body, url, prerelease, published_at)
    VALUES (@repo, @tag, @name, @body, @url, @prerelease, @published_at)
    ON CONFLICT(repo, tag) DO UPDATE SET
        name = excluded.name, body = excluded.body, url = excluded.url,
        prerelease = excluded.prerelease
`);

/** Release speichern/aktualisieren. Gibt true zurück, wenn neu (→ ankündigen). */
export function saveRelease(release) {
    const existed = db
        .prepare('SELECT 1 FROM releases WHERE repo = ? AND tag = ?')
        .get(release.repo, release.tag);
    upsertRelease.run(release);
    return !existed;
}

const selectReleases = db.prepare(`
    SELECT repo, tag, name, body, url, prerelease, published_at
    FROM releases ORDER BY published_at DESC LIMIT ? OFFSET ?
`);
const countReleasesStmt = db.prepare('SELECT count(*) AS n FROM releases');

export function listReleases(limit, offset) {
    return { items: selectReleases.all(limit, offset), total: countReleasesStmt.get().n };
}

/** Zahlen der letzten 7 Tage für den Wochen-Rückblick */
export function weeklyStats() {
    const perDay = db
        .prepare(`
            SELECT date(committed_at) AS day, count(*) AS n
            FROM commits WHERE committed_at >= datetime('now', '-7 days')
            GROUP BY day
        `)
        .all();
    const topRepos = db
        .prepare(`
            SELECT repo, count(*) AS n
            FROM commits WHERE committed_at >= datetime('now', '-7 days')
            GROUP BY repo ORDER BY n DESC LIMIT 3
        `)
        .all();
    const devlogs = db
        .prepare(`SELECT count(*) AS n FROM devlogs WHERE posted_at >= datetime('now', '-7 days')`)
        .get().n;
    return { perDay, topRepos, devlogs };
}

/** Statistiken fürs Status-Panel der Settings-Seite */
export function archiveStats() {
    return {
        devlogs: countDevlogsStmt.get().n,
        commits: countCommitsStmt.get().n,
        dbSizeBytes: statSync(dbFile).size,
    };
}