const std = @import("std");
const httpz = @import("httpz");
const helper = @import("helper.zig");

const Makko = @import("Makko.zig");
const QR = @import("qrcode").QR;
const Log = @import("Log.zig");

const getLanIP = @import("getLanIP.zig").getLanIP;

const Handle = struct {
    changed: std.atomic.Value(i16),
    log: Log,
    directory: std.fs.Dir,
    port: u16,

    pub fn update(self: *Handle) void {
        self.log.header("Reloading");
        _ = self.changed.fetchAdd(1, .monotonic);
    }

    pub fn dispatch(
        self: *Handle,
        action: httpz.Action(*Handle),
        req: *httpz.Request,
        res: *httpz.Response,
    ) !void {
        if (std.mem.startsWith(u8, req.url.path, "/.makko"))
            return action(self, req, res);

        const args = .{ @tagName(req.method), req.url.path };
        if (self.log.colors)
            self.log.raw("[{s}] \x1b[2m{s}\x1b[0m\n", args)
        else
            self.log.raw("[{s}] {s}\n", args);

        action(self, req, res) catch |err| {
            const writer = res.writer();
            try writer.print(
                @embedFile("gui/error.html"),
                .{ 500, req.url.path, err },
            );

            const query = try req.query();
            const enable_banner = query.get("makko-disable-banner") == null;

            if (enable_banner)
                try writer.writeAll(@embedFile("gui/banner.html"));

            res.content_type = .HTML;
            res.status = 500;
        };
    }
};

pub const Server = httpz.Server(*Handle);

pub fn init(
    makko: *Makko,
    public: bool,
    port: u16,
) !Server {
    const address = if (public) "0.0.0.0" else "127.0.0.1";

    const printable = if (public) blk: {
        var buffer: [32]u8 = undefined;
        if (getLanIP(&buffer)) |lan_ip| {
            try showQR(makko.allocator, lan_ip, port);
            break :blk lan_ip;
        }

        makko.log.err("Could not fetch local IP! No QR, sorry.", .{});
        break :blk "0.0.0.0";
    } else "127.0.0.1";

    var handler: Handle = .{
        .changed = .{ .raw = 0 },
        .directory = makko.paths.output,
        .log = makko.log,
        .port = port,
    };

    var server = try Server.init(
        makko.allocator,
        .{
            .port = port,
            .address = address,
        },
        &handler,
    );

    var router = try server.router(.{});

    router.get("/*", static, .{});
    router.get("/", redirect, .{});
    router.get("/.makko/state", state, .{});
    router.get("/.makko/", makko_ui, .{});

    handler.log.info("Serving at http://{s}:{}/\n", .{ printable, port });

    return server;
}

// For rendering our QR code
fn showQR(allocator: std.mem.Allocator, address: []const u8, port: u16) !void {
    const whole = try std.fmt.allocPrint(
        allocator,
        "http://{s}:{}",
        .{ address, port },
    );
    defer allocator.free(whole);

    var qr = try QR.fromText(allocator, 2, .low, whole);
    defer qr.deinit();

    const stdout = std.io.getStdOut();
    const writer = stdout.writer();

    try writer.writeByte(' '); // small left margin

    // We iterate through each pixel of the QR code and
    // we render it using ASCII codes.
    var y: usize = 0;
    while (y < qr.size) : (y += 2) {
        try writer.writeAll("\n  ");

        for (0..qr.size) |x| {
            const top = qr.getModule(@intCast(x), @intCast(y));
            const bottom = qr.getModule(@intCast(x), @intCast(y + 1));

            const char = if (top and bottom)
                "█"
            else if (top and !bottom)
                "▀"
            else if (!top and bottom)
                "▄"
            else
                " ";

            try writer.writeAll(char);
        }
    }

    try writer.writeAll("\n\n");
}

// in case we want to access either /directory/ or just /, we redirect to
// /directory/index.html and /index.html
fn redirect(_: *Handle, req: *httpz.Request, res: *httpz.Response) !void {
    const query = try req.query();
    const enable_banner = query.get("makko-disable-banner") == null;

    const alloc = try std.mem.concat(res.arena, u8, &.{
        req.url.path,
        "index.html",
        if (!enable_banner) "?makko-disable-banner=1" else "",
    });
    res.headers.add("Location", alloc);
    res.status = 308;
    return;
}

fn makko_ui(handle: *Handle, req: *httpz.Request, res: *httpz.Response) !void {
    const addr = req.conn.address.in.sa.addr;

    // checks if NOT accessing from eiher 127.0.0.1 or 0.0.0.0
    const is_local = addr == 0x0100007f or addr == 0;
    if (!is_local) {
        const new_addr =
            try std.fmt.allocPrint(res.arena, "http://localhost:{}/.makko", .{handle.port});

        res.headers.add("Location", new_addr);
        res.status = 308;
        return;
    }

    const writer = res.writer();
    try writer.writeAll(@embedFile("gui/shell.html"));
    res.content_type = .HTML;
    res.status = 200;
}

fn state(handle: *Handle, _: *httpz.Request, res: *httpz.Response) !void {
    try res.writer().print("{}", .{handle.changed.raw});
    res.status = 200;
    res.content_type = .TEXT;
}

fn static(handle: *Handle, req: *httpz.Request, res: *httpz.Response) !void {
    const query = try req.query();
    const enable_banner = query.get("makko-disable-banner") == null;

    const path = req.url.path[1..];

    // If path is a directory, attempt to redirect to $(path)/index.html
    if (path[path.len - 1] == '/')
        return try redirect(handle, req, res);

    const output = handle.directory;
    if (!helper.exists(output, path)) {
        const writer = res.writer();
        try writer.print(
            @embedFile("gui/error.html"),
            .{ 404, path, error.FileNotFound },
        );

        if (enable_banner)
            try writer.writeAll(@embedFile("gui/banner.html"));

        res.content_type = .HTML;
        res.status = 404;
        return;
    }

    // open the file!
    const file = try output.openFile(path, .{});
    defer file.close();

    res.content_type = httpz.ContentType.forFile(path);

    const writer = res.writer();
    const size = try file.getEndPos();

    // we read the file up and write as we read
    var file_buf: [4096]u8 = undefined;
    var remaining = size;
    while (remaining > 0) {
        const len = try file.read(&file_buf);
        if (len == 0) break;
        remaining -= len;
        try writer.writeAll(file_buf[0..len]);
    }

    // we inject the banner if we're dealing with HTML
    if (enable_banner and res.content_type.? == .HTML)
        try writer.writeAll(@embedFile("gui/banner.html"));

    try res.write();
    res.status = 200;
}