import { Database } from "bun:sqlite";
import { mkdirSync } from "node:fs";
import { join } from "node:path";

// §19: only what the pages, the sync loop and issues use so far; later phases add their tables.
const SCHEMA = `
CREATE TABLE IF NOT EXISTS settings (
	key   TEXT PRIMARY KEY,
	value TEXT NOT NULL
);
CREATE TABLE IF NOT EXISTS repos (
	name            TEXT PRIMARY KEY,
	public          INTEGER NOT NULL DEFAULT 0,
	category        TEXT NOT NULL DEFAULT '',
	homepage        TEXT NOT NULL DEFAULT '',
	languages       TEXT NOT NULL DEFAULT '',
	issues_paused   INTEGER NOT NULL DEFAULT 0,
	hidden_paths    TEXT NOT NULL DEFAULT '',
	last_sync_at    INTEGER,
	last_sync_error TEXT
);
-- §24: the admin console hides a version or replaces its notes; NULL notes keep the record's.
CREATE TABLE IF NOT EXISTS release_settings (
	repo    TEXT NOT NULL,
	version TEXT NOT NULL,
	hidden  INTEGER NOT NULL DEFAULT 0,
	notes   TEXT,
	PRIMARY KEY (repo, version)
);
-- §22.2: one count per release file; installs are Nix tarball fetches, per repo.
CREATE TABLE IF NOT EXISTS downloads (
	repo     TEXT NOT NULL,
	version  TEXT NOT NULL,
	platform TEXT NOT NULL,
	count    INTEGER NOT NULL DEFAULT 0,
	PRIMARY KEY (repo, version, platform)
);
CREATE TABLE IF NOT EXISTS installs (
	repo  TEXT PRIMARY KEY,
	count INTEGER NOT NULL DEFAULT 0
);
-- §23. Numbers are per repo and set explicitly, so Kepr 2's carry over on import. The contact
-- email is the operator's alone; token_hash is the follow-up link's SHA-256 (NULL for imports).
CREATE TABLE IF NOT EXISTS issues (
	id            INTEGER PRIMARY KEY,
	repo          TEXT NOT NULL,
	number        INTEGER NOT NULL,
	title         TEXT NOT NULL,
	body          TEXT NOT NULL,
	type          TEXT NOT NULL CHECK (type IN ('bug', 'idea', 'question')),
	version       TEXT NOT NULL DEFAULT '',
	reporter_name TEXT NOT NULL DEFAULT '',
	contact_email TEXT NOT NULL DEFAULT '',
	filed_at      INTEGER NOT NULL,
	status        TEXT NOT NULL DEFAULT 'open' CHECK (status IN ('open', 'closed')),
	closed_at     INTEGER,
	fixed_in      TEXT NOT NULL DEFAULT '',
	hidden        INTEGER NOT NULL DEFAULT 0,
	ip_hash       TEXT NOT NULL DEFAULT '',
	token_hash    TEXT,
	UNIQUE (repo, number)
);
CREATE INDEX IF NOT EXISTS issues_ip ON issues (ip_hash, filed_at);
-- The thread after the first post: the reporter's follow-ups and the operator's replies.
CREATE TABLE IF NOT EXISTS issue_entries (
	id         INTEGER PRIMARY KEY,
	issue_id   INTEGER NOT NULL REFERENCES issues (id),
	author     TEXT NOT NULL CHECK (author IN ('reporter', 'operator')),
	body       TEXT NOT NULL,
	created_at INTEGER NOT NULL,
	hidden     INTEGER NOT NULL DEFAULT 0
);
CREATE INDEX IF NOT EXISTS issue_entries_issue ON issue_entries (issue_id, id);
-- §24: admin sessions, revocable; only the SHA-256 of the cookie's token is kept.
CREATE TABLE IF NOT EXISTS sessions (
	token_hash TEXT PRIMARY KEY,
	expires_at INTEGER NOT NULL
);
-- June's own words for a repo, edited on its page when signed in; '' falls back to the README.
CREATE TABLE IF NOT EXISTS repo_text (
	repo        TEXT PRIMARY KEY,
	description TEXT NOT NULL DEFAULT '',
	details     TEXT NOT NULL DEFAULT ''
);
CREATE TABLE IF NOT EXISTS connect_codes (
	code_hash   TEXT PRIMARY KEY,
	machine     TEXT NOT NULL,
	created_at  INTEGER NOT NULL,
	expires_at  INTEGER NOT NULL,
	used_at     INTEGER
);
-- §24: what Kepr tells the operator in the console, newest 200 kept.
CREATE TABLE IF NOT EXISTS notifications (
	id         INTEGER PRIMARY KEY,
	kind       TEXT NOT NULL,
	text       TEXT NOT NULL,
	href       TEXT NOT NULL,
	created_at INTEGER NOT NULL,
	read       INTEGER NOT NULL DEFAULT 0
);
-- §24: notifications on their way to the operator's inbox; the address is kepr.toml's.
CREATE TABLE IF NOT EXISTS email_queue (
	id         INTEGER PRIMARY KEY,
	subject    TEXT NOT NULL,
	href       TEXT NOT NULL,
	status     TEXT NOT NULL DEFAULT 'waiting' CHECK (status IN ('waiting', 'sent', 'failed')),
	attempts   INTEGER NOT NULL DEFAULT 0,
	next_at    INTEGER NOT NULL,
	last_error TEXT NOT NULL DEFAULT '',
	created_at INTEGER NOT NULL,
	sent_at    INTEGER
);
`;

/** What raises a notification (§24); each can be switched off. */
export const NOTIFICATION_KINDS = [
	"issue_filed",
	"issue_followup",
	"sync_failed",
	"backup_failed",
] as const;
export type NotificationKind = (typeof NOTIFICATION_KINDS)[number];
const NOTIFICATIONS_KEPT = 200;

// Columns added after the first kepr.db was made; SQLite has no ADD COLUMN IF NOT EXISTS.
const ADDED_COLUMNS: [table: string, column: string, definition: string][] = [
	["repos", "languages", "TEXT NOT NULL DEFAULT ''"],
	["repos", "issues_paused", "INTEGER NOT NULL DEFAULT 0"],
	["issue_entries", "hidden", "INTEGER NOT NULL DEFAULT 0"],
	["repos", "hidden_paths", "TEXT NOT NULL DEFAULT ''"],
];
// Columns an older kepr.db still has; card order and install lines were removed (June, 2026-09-30).
const DROPPED_COLUMNS: [table: string, column: string][] = [
	["repos", "sort_order"],
	["repos", "install1"],
	["repos", "install2"],
	["repos", "install3"],
];

/** `description` and `details` are the operator's Markdown, or '' for the README's. */
export type RepoSettings = {
	name: string;
	category: string;
	homepage: string;
	/** The operator's shown languages (§24), or none for the detected one. */
	languages: string[];
	/** Filing is paused (§23); the list, threads and follow-ups carry on. */
	issuesPaused: boolean;
	description: string;
	details: string;
};

export type RepoText = "description" | "details";

type RepoRow = {
	name: string;
	category: string;
	homepage: string;
	languages: string;
	issues_paused: number;
	description: string | null;
	details: string | null;
};

export function openKeprDb(dataDir: string): Database {
	mkdirSync(dataDir, { recursive: true });
	const db = new Database(join(dataDir, "kepr.db"), { strict: true });
	db.run("PRAGMA journal_mode = WAL");
	db.run("PRAGMA busy_timeout = 5000");
	db.run(SCHEMA);
	// Every name below comes from the two lists above, never from input.
	const has = (table: string, column: string) =>
		db
			.query<{ name: string }, []>(`PRAGMA table_info(${table})`)
			.all()
			.some((existing) => existing.name === column);
	for (const [table, column, definition] of ADDED_COLUMNS) {
		if (!has(table, column)) db.run(`ALTER TABLE ${table} ADD COLUMN ${column} ${definition}`);
	}
	for (const [table, column] of DROPPED_COLUMNS) {
		if (has(table, column)) db.run(`ALTER TABLE ${table} DROP COLUMN ${column}`);
	}
	return db;
}

export function setting(db: Database, key: string): string | null {
	const row = db
		.query<{ value: string }, [string]>("SELECT value FROM settings WHERE key = ?")
		.get(key);
	return row?.value ?? null;
}

/** Every repo starts private (§20); registering a known repo changes nothing. */
export function registerRepo(db: Database, name: string): void {
	db.query("INSERT OR IGNORE INTO repos (name) VALUES (?)").run(name);
}

/**
 * Tells the operator, unless that kind is switched off, and queues an email when that kind is
 * emailed. The newest 200 of each are kept.
 */
export function notify(db: Database, kind: NotificationKind, text: string, href: string): void {
	const now = Math.floor(Date.now() / 1000);
	db.transaction(() => {
		if (!setting(db, `notify_off_${kind}`)) {
			db.query("INSERT INTO notifications (kind, text, href, created_at) VALUES (?, ?, ?, ?)").run(
				kind,
				text,
				href,
				now,
			);
		}
		if (setting(db, `email_on_${kind}`)) {
			db.query(
				"INSERT INTO email_queue (subject, href, next_at, created_at) VALUES (?, ?, ?, ?)",
			).run(text, href, now, now);
		}
		for (const table of ["notifications", "email_queue"]) {
			// `table` is one of the two names above, never input.
			db.query(
				`DELETE FROM ${table}
				WHERE id NOT IN (SELECT id FROM ${table} ORDER BY id DESC LIMIT ?)`,
			).run(NOTIFICATIONS_KEPT);
		}
	})();
}

/** Records a sync's outcome; a repo that starts failing tells the operator, once. */
export function recordSync(db: Database, name: string, at: number, error: string | null): void {
	const before = db
		.query<{ last_sync_error: string | null }, [string]>(
			"SELECT last_sync_error FROM repos WHERE name = ?",
		)
		.get(name);
	if (error && !before?.last_sync_error) {
		notify(db, "sync_failed", `Sync failed for ${name}: ${error}`, `/admin/repos?repo=${name}`);
	}
	db.query("UPDATE repos SET last_sync_at = ?, last_sync_error = ? WHERE name = ?").run(
		at,
		error,
		name,
	);
}

export function publicRepoNames(db: Database): string[] {
	return db
		.query<{ name: string }, []>("SELECT name FROM repos WHERE public = 1 ORDER BY name")
		.all()
		.map((row) => row.name);
}

/** The settings of a public repo, or null when it is private or unknown: both must look missing. */
export function publicRepo(db: Database, name: string): RepoSettings | null {
	const row = db
		.query<RepoRow, [string]>(
			`SELECT name, category, homepage, languages, issues_paused, description, details
			FROM repos LEFT JOIN repo_text ON repo_text.repo = repos.name
			WHERE name = ? AND public = 1`,
		)
		.get(name);
	if (!row) return null;
	return {
		name: row.name,
		category: row.category,
		homepage: row.homepage,
		languages: row.languages === "" ? [] : row.languages.split(", "),
		issuesPaused: row.issues_paused === 1,
		description: row.description ?? "",
		details: row.details ?? "",
	};
}

/** The paths the operator hid from a repo (June, 2026-09-30), one per line in kepr.db. */
export function hiddenPaths(db: Database, repo: string): string[] {
	const row = db
		.query<{ hidden_paths: string }, [string]>("SELECT hidden_paths FROM repos WHERE name = ?")
		.get(repo);
	return row?.hidden_paths ? row.hidden_paths.split("\n") : [];
}

/** A repo's own texts, public or not; '' where the README speaks. */
export function repoText(db: Database, repo: string): Record<RepoText, string> {
	return (
		db
			.query<Record<RepoText, string>, [string]>(
				"SELECT description, details FROM repo_text WHERE repo = ?",
			)
			.get(repo) ?? { description: "", details: "" }
	);
}

/** Sets one of a repo's texts; '' hands it back to the README. */
export function setRepoText(db: Database, repo: string, field: RepoText, value: string): void {
	db.query("INSERT OR IGNORE INTO repo_text (repo) VALUES (?)").run(repo);
	// `field` is one of two column names, never input.
	db.query(`UPDATE repo_text SET ${field} = ? WHERE repo = ?`).run(value, repo);
}