const std = @import("std");
const http = @import("apple_pie");

const images_dir_path = "./images";

pub fn main() anyerror!void {
    std.log.info("All your codebase are belong to us.", .{});

    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();

    const bind_addr = try std.net.Address.parseIp("0.0.0.0", 8080);
    std.log.info("serving on {}", .{bind_addr});

    // TODO: configurable path via env var
    try std.fs.cwd().makePath(images_dir_path);

    try http.listenAndServe(
        &gpa.allocator,
        bind_addr,
        comptime http.router.router(&[_]http.router.Route{
            http.router.get("/", index),
            http.router.post("/api/upload", uploadFile),
            http.router.post("/:filename", fetchFile),
        }),
    );
}

fn index(response: *http.Response, request: http.Request) !void {
    try response.writer().writeAll("Hello Zig!");
}

fn generateImageId(buffer: []u8) []const u8 {
    var i: usize = 0;

    const seed = @truncate(u64, @bitCast(u128, std.time.nanoTimestamp()));
    var r = std.rand.DefaultPrng.init(seed);

    while (i < 16) : (i += 1) {
        // random ascii lowercase char
        var idx = @intCast(u8, r.random.uintLessThan(u5, 24));
        var letter = @as(u8, 97) + idx;
        buffer[i] = letter;
    }

    return buffer[0..i];
}

fn uploadFile(response: *http.Response, request: http.Request) !void {
    std.log.info("upload! got {d} bytes", .{request.body.len});

    var image_id_buffer: [256]u8 = undefined;
    const image_id = generateImageId(&image_id_buffer);

    var image_path_buffer: [512]u8 = undefined;
    const image_path = try std.fmt.bufPrint(
        &image_path_buffer,
        "{s}/{s}.jpg",
        .{ images_dir_path, image_id },
    );

    const image_file = try std.fs.cwd().createFile(image_path, .{});
    try image_file.writer().writeAll(request.body);

    try response.writer().writeAll(image_path);
}

fn fetchFile(response: *http.Response, request: http.Request, filename: []const u8) !void {
    std.log.info("got name: {s}", .{filename});
    const images_dir = try std.fs.cwd().openDir(images_dir_path, .{});
    try response.writer().writeAll("Hello Zig! fetch");
}