import type { Database } from "bun:sqlite";
import * as TID from "@atcute/tid";
import { getDevAccounts } from "../../atproto/env.ts";
import { createDiff } from "../../lib/diff.ts";
import { LIMITS } from "../../lib/limits.ts";

interface SeedNote {
	slug: string;
	title: string;
	content: string;
}

function seedWiki(
	db: Database,
	owner: { did: string; handle: string },
	slug: string,
	name: string,
	description: string,
	notes: SeedNote[],
): void {
	const wikiAtUri = `at://${owner.did}/wiki.lichen.wiki/${slug}`;
	db.run(
		"INSERT INTO wikis (slug, did, name, visibility, description, at_uri) VALUES (?, ?, ?, ?, ?, ?)",
		[slug, owner.did, name, "public", description, wikiAtUri],
	);
	db.run(
		"INSERT INTO memberships (wiki_at_uri, wiki_slug, did, role, at_uri) VALUES (?, ?, ?, ?, ?)",
		[
			wikiAtUri,
			slug,
			owner.did,
			"admin",
			`at://${owner.did}/wiki.lichen.membership/${TID.now()}`,
		],
	);

	for (const note of notes) {
		const noteAtUri = `at://${owner.did}/wiki.lichen.note/${TID.now()}`;
		const revisionAtUri = `at://${owner.did}/wiki.lichen.noteRevision/${TID.now()}`;
		db.run(
			"INSERT INTO notes (slug, wiki_at_uri, wiki_slug, title, did, at_uri) VALUES (?, ?, ?, ?, ?, ?)",
			[note.slug, wikiAtUri, slug, note.title, owner.did, noteAtUri],
		);
		// Initial revision + snapshot so the seeded note has a history entry.
		db.run(
			`INSERT INTO revisions (note_at_uri, did, at_uri, parent_revision_uri, diff, message)
			 VALUES (?, ?, ?, NULL, ?, ?)`,
			[
				noteAtUri,
				owner.did,
				revisionAtUri,
				createDiff("", note.content),
				"Initial content",
			],
		);
		db.run(
			"INSERT INTO snapshots (note_at_uri, revision_at_uri, content) VALUES (?, ?, ?)",
			[noteAtUri, revisionAtUri, note.content],
		);
		db.run(
			`INSERT INTO current_note (note_at_uri, content, latest_revision_uri, updated_at)
			VALUES (?, ?, ?, datetime('now'))`,
			[noteAtUri, note.content, revisionAtUri],
		);
	}
}

// A note whose revision count exceeds the snapshot cap, so the oldest entries in
// its history view fall back to on-demand diff reconstruction (the snapshots have
// been evicted, exactly as in production). Mirrors the appendRevision + capSnapshots
// flow with raw SQL to stay consistent with the rest of the seed.
function seedNoteWithHistory(
	db: Database,
	owner: { did: string },
	wikiSlug: string,
	note: { slug: string; title: string; versions: string[] },
): void {
	const wikiAtUri = `at://${owner.did}/wiki.lichen.wiki/${wikiSlug}`;
	const noteAtUri = `at://${owner.did}/wiki.lichen.note/${TID.now()}`;
	db.run(
		"INSERT INTO notes (slug, wiki_at_uri, wiki_slug, title, did, at_uri) VALUES (?, ?, ?, ?, ?, ?)",
		[note.slug, wikiAtUri, wikiSlug, note.title, owner.did, noteAtUri],
	);

	let parent: string | null = null;
	let prev = "";
	let latest = "";
	for (const [i, content] of note.versions.entries()) {
		const revAtUri = `at://${owner.did}/wiki.lichen.noteRevision/${TID.now()}`;
		db.run(
			`INSERT INTO revisions (note_at_uri, did, at_uri, parent_revision_uri, diff, message)
			 VALUES (?, ?, ?, ?, ?, ?)`,
			[
				noteAtUri,
				owner.did,
				revAtUri,
				parent,
				createDiff(prev, content),
				i === 0 ? "Initial content" : `Edit ${i}`,
			],
		);
		db.run(
			"INSERT INTO snapshots (note_at_uri, revision_at_uri, content) VALUES (?, ?, ?)",
			[noteAtUri, revAtUri, content],
		);
		parent = revAtUri;
		prev = content;
		latest = revAtUri;
	}

	db.run(
		`INSERT INTO current_note (note_at_uri, content, latest_revision_uri, updated_at)
		 VALUES (?, ?, ?, datetime('now'))`,
		[noteAtUri, prev, latest],
	);
	// Keep only the most recent snapshots, as capSnapshots does on every ingest.
	db.run(
		`DELETE FROM snapshots WHERE note_at_uri = ? AND id NOT IN (
			SELECT id FROM snapshots WHERE note_at_uri = ? ORDER BY id DESC LIMIT ?
		)`,
		[noteAtUri, noteAtUri, LIMITS.snapshotCap],
	);
}

// Builds a multi-version changelog: each edit appends one line, so old revisions
// render as clean single-line insertions once reconstructed.
function changelogVersions(): string[] {
	let body = `# Changelog

A note with a long edit history, used to exercise diff reconstruction for
revisions older than the snapshot cap.
`;
	const versions = [body];
	for (let i = 1; i <= 30; i++) {
		body += `\n- Entry ${i}: documented change number ${i}.`;
		versions.push(body);
	}
	return versions;
}

export function seedIfEmpty(db: Database): void {
	const count = db.query("SELECT COUNT(*) as n FROM wikis").get() as {
		n: number;
	};
	if (count.n > 0) return;

	const accounts = getDevAccounts();
	if (!accounts) return;
	const alice = accounts["alice"];
	const bob = accounts["bob"];
	if (!alice || !bob) return;

	console.log("Seeding database with sample data...");

	db.run("BEGIN TRANSACTION");
	try {
		for (const account of Object.values(accounts)) {
			db.run(
				"INSERT OR IGNORE INTO profile_cache (did, handle) VALUES (?, ?)",
				[account.did, account.handle],
			);
		}

		seedWiki(
			db,
			alice,
			"alices-garden",
			"Alice's Garden",
			"A sample public wiki owned by Alice for exploring Lichen.",
			[
				{
					slug: "home",
					title: "Home",
					content: `# Welcome to Alice's Garden

This is the **home page**. Try editing it, then check the history.

- [[hello|Hello]] — a sample note
- [[@bob.test/bobs-notebook/home|Bob's Notebook]] — Alice contributes there too
`,
				},
				{
					slug: "hello",
					title: "Hello",
					content: `# Hello

A short note. Edit me to see how diffs work.
`,
				},
			],
		);

		// >25 revisions: its oldest history entries render via reconstruction.
		seedNoteWithHistory(db, alice, "alices-garden", {
			slug: "changelog",
			title: "Changelog",
			versions: changelogVersions(),
		});

		seedWiki(
			db,
			bob,
			"bobs-notebook",
			"Bob's Notebook",
			"A sample public wiki owned by Bob. Alice has contributor access.",
			[
				{
					slug: "home",
					title: "Home",
					content: `# Bob's Notebook

Bob owns this wiki. Alice can edit notes here as a contributor.
`,
				},
			],
		);

		// Alice is a contributor on Bob's wiki — log in as alice and edit it.
		db.run(
			"INSERT INTO memberships (wiki_at_uri, wiki_slug, did, role, at_uri) VALUES (?, ?, ?, ?, ?)",
			[
				`at://${bob.did}/wiki.lichen.wiki/bobs-notebook`,
				"bobs-notebook",
				alice.did,
				"contributor",
				`at://${bob.did}/wiki.lichen.membership/${TID.now()}`,
			],
		);

		db.run("COMMIT");
	} catch (err) {
		db.run("ROLLBACK");
		throw err;
	}
}