import * as sqlite from "jsr:@db/sqlite@0.11";
import * as oak from "jsr:@oak/oak@14";
import * as bcrypt from "https://deno.land/x/bcrypt@v0.4.1/mod.ts";

type User = {
    id: number;
    username: string;
    passwordHash: string;
};

type Session = {
    id: number;
    token: string;
    userId: number;
    username: string;
};

interface Db {
    userWhereUsername(username: string): Promise<User | null>;
    sessionWhereToken(token: string): Promise<Session | null>;
    createSession(init: Omit<Session, "id">): Promise<Session>;
}

class SqliteDb implements Db {
    private db = new sqlite.Database("bunker.db", { create: false });

    public async userWhereUsername(username: string): Promise<User | null> {
        await Promise.resolve();
        const res = this.db.prepare(
            "select rowid as id, * from users where username=?",
        )
            .value<[User]>(username);
        if (!res) {
            return null;
        }
        return ["id", "username", "passwordHash"]
            .map((key, index) => ({ [key]: res[index] }))
            .reduce<Partial<User>>(
                (acc, kv) => ({ ...acc, ...kv }),
                {},
            ) as User;
    }
    public async sessionWhereToken(token: string): Promise<Session | null> {
        await Promise.resolve();
        const res = this.db.prepare(
            "select rowid as id, * from sessions where token=?",
        )
            .value<[Session]>(token);
        if (!res) {
            return null;
        }
        return ["id", "token", "userId", "username"]
            .map((key, index) => ({ [key]: res[index] }))
            .reduce<Partial<User>>(
                (acc, kv) => ({ ...acc, ...kv }),
                {},
            ) as Session;
    }
    public async deleteSessionsWithUsername(username: string): Promise<void> {
        await Promise.resolve();
        this.db.exec("delete from sessions where username=?", username);
    }
    public async createSession(init: Omit<Session, "id">): Promise<Session> {
        await Promise.resolve();
        this.db.exec(
            "insert into sessions (token, userId, username) values (:token, :userId, :username)",
            init,
        );
        const res = this.db.prepare(
            "select rowid as id, * from sessions where username=? and token=?",
        )
            .value<[Session]>(init.username, init.token)!;
        return ["id", "token", "userId", "username"]
            .map((key, index) => ({ [key]: res[index] }))
            .reduce<Partial<User>>(
                (acc, kv) => ({ ...acc, ...kv }),
                {},
            ) as Session;
    }
}

const db = new SqliteDb();

type LoginReq = {
    username: string;
    password: string;
};

function respond<
    Ctx extends {
        respond: boolean;
        // deno-lint-ignore no-explicit-any
        response: { status: oak.Status; body: any };
    },
> // deno-lint-ignore no-explicit-any
(ctx: Ctx, status: oak.Status, body: any) {
    ctx.respond = true;
    ctx.response.status = status;
    ctx.response.body = body;
}

function generateToken(): string {
    let token = "";
    const alfabet =
        "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXUZ123456789";
    for (let i = 0; i < 64; ++i) {
        token += alfabet[Math.random() * alfabet.length];
    }
    return token;
}

const publicRouter = new oak.Router()
    .get("/favicon.ico", async (ctx) => {
        await ctx.send({ path: ctx.request.url.pathname, root: "./public" });
    })
    .get("/login.html", async (ctx) => {
        await ctx.send({ path: ctx.request.url.pathname, root: "./public" });
    })
    .get("/login.js", async (ctx) => {
        await ctx.send({ path: ctx.request.url.pathname, root: "./public" });
    })
    .post("/api/login", async (ctx) => {
        const body = await ctx.request.body.json() as LoginReq;
        if (
            typeof body.username !== "string" ||
            typeof body.password !== "string"
        ) {
            return respond(ctx, 400, { ok: false, msg: "malformed request" });
        }
        const user = await db.userWhereUsername(body.username);
        if (!user) {
            return respond(ctx, 401, { ok: false, msg: "bad creds1" });
        }
        if (!await bcrypt.compare(body.password, user.passwordHash)) {
            return respond(ctx, 401, { ok: false, msg: "bad creds2" });
        }
        await db.deleteSessionsWithUsername(user.username);
        const token = generateToken();
        await db.createSession({
            token,
            userId: user.id,
            username: user.username,
        });
        await ctx.cookies.set("Authorization", token, { sameSite: "strict" });
        return respond(ctx, 200, { ok: true });
    });

function authMiddleware(): oak.Middleware {
    return async (ctx, next) => {
        const token = await ctx.cookies.get("Authorization");
        if (!token || !await db.sessionWhereToken(token)) {
            const path = encodeURIComponent(ctx.request.url.pathname);
            ctx.response.redirect(`/login.html?refer=${path}`);
            return;
        }
        await next();
    };
}

async function listFilesInFolder(folderPath: string): Promise<string[]> {
    if (!/^\/files\//.test(folderPath)) {
        throw new Error("malformed path");
    }
    folderPath = folderPath.replace(/^\/files\//, "./files/");
    const command = new Deno.Command("ls", {
        args: ["-1F", "--group-directories-first", folderPath],
        stdout: "piped",
    });
    const output = await command.output();
    const text = new TextDecoder().decode(output.stdout);
    return text
        .split("\n")
        .filter((v) => v);
}

function listPage(folderPath: string, files: string[]): string {
    const filesHtml = files.map((filename) => /*html*/ `
        <li><a href="./${filename}">${filename}</a></li>
    `).join("\n");
    return /*html*/ `
        <!DOCTYPE html>
        <html>
            <meta charset="utf-8">
            <meta name="viewport" content="width=device-width, initial-scale=1.0">
            <title>Bunker ${folderPath}</title>
        <head>
        </head>
        <body>
            <p><a href="/">Home</a></p>
            <p>${folderPath}</p>
            <ul>
                <li><a href="..">..</a></li>
                ${filesHtml}
            </ul>
        </body>
        </html>
    `.replace(/^ {8}/gm, "");
}

const authRouter = new oak.Router();

new oak.Application()
    .use(publicRouter.routes())
    .use(publicRouter.allowedMethods())
    .use(authMiddleware(), authRouter.routes())
    .use(authMiddleware(), authRouter.allowedMethods())
    .use(authMiddleware(), async (ctx) => {
        const { request: { url: { pathname } } } = ctx;
        if (pathname.startsWith("/files/")) {
            const name = decodeURIComponent(pathname);
            const info = await Deno.stat(
                name.replace(/^\/files\//, "files/"),
            );
            if (name.endsWith("/") || info.isDirectory) {
                const files = await listFilesInFolder(name);
                ctx.response.type = "text/html";
                ctx.response.body = listPage(name, files);
                ctx.response.status = 200;
                ctx.respond = true;
                return;
            }
            await oak.send(
                ctx,
                name
                    .replace(/^\/files\//, "")
                    .replaceAll("..", "."),
                {
                    root: "./files",
                },
            );
            return;
        }
        await oak.send(ctx, pathname, {
            root: "./public",
            index: "index.html",
        });
    })
    .listen({ port: 8000 });