use std::io::{stdin, Read, Write};
use anyhow::{anyhow, Result};
use libtls::{config::Builder, tls::Tls};
use pico_args::Arguments;
use url::{Position, Url};
#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
enum Status {
    Input,
    Success,
    Redirect,
    TemporaryFailure,
    PermanentFailure,
    ClientCertificateRequired,
}
#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq)]
struct Header {
    status: u8,
    meta: String,
}
impl Header {
    pub fn status(&self) -> Status {
        if self.status >= 60 {
            Status::ClientCertificateRequired
        } else if self.status >= 50 {
            Status::PermanentFailure
        } else if self.status >= 40 {
            Status::TemporaryFailure
        } else if self.status >= 30 {
            Status::Redirect
        } else if self.status >= 20 {
            Status::Success
        } else if self.status >= 10 {
            Status::Input
        } else {
            panic!("invalid status: {}", self.status)
        }
    }
}
fn parse_address(mut address: String) -> Result<Url> {
    if !address.trim_start().starts_with("gemini://") {
        if address.contains("://") {
            return Err(anyhow!("only gemini is supported"));
        }
        address = format!("gemini://{}", address);
    }
    let mut url = Url::parse(address.as_str())?;
    if !url.username().is_empty() || url.password().is_some() {
        return Err(anyhow!("no user info is allowed"));
    }
    if !url.has_host() {
        return Err(anyhow!("must supply host"));
    }
    if url.port().is_none() {
        url.set_port(Some(1965)).expect("port error")
    }
    Ok(url)
}
fn make_request(url: &Url) -> Result<(Header, String)> {
    let mut client = Tls::client()?;
    let config = Builder::new().noverifycert().build()?;
    client.configure(&config)?;
    // Open Connection
    client.connect(&url[Position::BeforeHost..Position::AfterPort], None)?;
    // Complete TLS handshake
    let shaken = client.tls_handshake()?;
    if shaken != 0 {
        return Err(anyhow!("tls handshake failed"));
    }
    // Validate Server Certificate
    // per section 4.2, we opt not to validate TLS connections beyond the handshake
    // Send request
    let req = format!("{}\r\n", url);
    let written = client.write(req.as_bytes())?;
    if written == 0 {
        return Err(anyhow!("failed to write request"));
    } else if written != req.len() {
        eprintln!(
            "warning: request was {} bytes, only wrote {}",
            req.len(),
            written
        )
    }
    // Handle response
    let mut res = String::new();
    let read = client.read_to_string(&mut res)?;
    if read == 0 {
        return Err(anyhow!("failed to read response"));
    }
    let line_break = res
        .match_indices("\r\n")
        .next()
        .expect("response missing CRLF")
        .0;
    // 2 status + 1 space + 1024 meta
    if line_break >= 1028 {
        return Err(anyhow!("meta was too long"));
    }
    let body = res.split_off(line_break);
    let header = Header {
        status: (&res[..2]).parse().unwrap(),
        meta: (&res[2..]).to_string(),
    };
    Ok((header, body))
}
fn handle_response(url: Url, header: Header, body: String) -> Result<()> {
    println!("status: {}", header.status);
    Ok(match header.status() {
        Status::Input => {
            println!("server is requesting input");
            println!("{}", header.meta);
            print!("> ");
            let mut line = String::from("?");
            stdin().read_line(&mut line)?;
            let with_input = url.join(line.as_str())?;
            println!("connecting to {} again with new input", with_input);
            let (header, body) = make_request(&with_input)?;
            handle_response(with_input, header, body)?
        }
        Status::Success => {
            // ignoring meta
            println!("{}", body)
        }
        Status::Redirect => {
            let address = header.meta;
            let redirect = parse_address(address)?;
            println!("redirecting {} to {}", url, redirect);
            let (header, body) = make_request(&redirect)?;
            handle_response(redirect, header, body)?
        }
        Status::TemporaryFailure | Status::PermanentFailure => {
            eprintln!("error from server");
            eprintln!("{}", header.meta)
        }
        Status::ClientCertificateRequired => {
            eprintln!("server requires a client certificate");
            eprintln!("{}", header.meta)
        }
    })
}
fn main() -> Result<()> {
    let mut args = Arguments::from_env();
    let address: String = args.free_from_str()?.expect("must supply address");
    let url = parse_address(address)?;
    println!("connecting to {}", url);
    let (header, body) = make_request(&url)?;
    handle_response(url, header, body)
}

[package]
authors = ["Matthew Ess <daringseal@gmail.com>"]
edition = "2018"
name    = "sputnik"
version = "0.1.0"
# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
[dependencies]
anyhow    = "1.0.37"
libtls    = "1.2.0"
pico-args = "0.3.4"
url       = "2.2.0"

# This file has been generated by Niv.
let
  #
  # The fetchers. fetch_<type> fetches specs of type <type>.
  #
  fetch_file = pkgs: spec:
    if spec.builtin or true then
      builtins_fetchurl { inherit (spec) url sha256; }
    else
      pkgs.fetchurl { inherit (spec) url sha256; };
  fetch_tarball = pkgs: name: spec:
    let
      ok = str: !builtins.isNull (builtins.match "[a-zA-Z0-9+-._?=]" str);
      # sanitize the name, though nix will still fail if name starts with period
      name' = stringAsChars (x: if !ok x then "-" else x) "${name}-src";
    in if spec.builtin or true then
      builtins_fetchTarball {
        name = name';
        inherit (spec) url sha256;
      }
    else
      pkgs.fetchzip {
        name = name';
        inherit (spec) url sha256;
      };
  fetch_git = spec:
    builtins.fetchGit {
      url = spec.repo;
      inherit (spec) rev ref;
    };
  fetch_local = spec: spec.path;
  fetch_builtin-tarball = name:
    throw ''
      [${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
              $ niv modify ${name} -a type=tarball -a builtin=true'';
  fetch_builtin-url = name:
    throw ''
      [${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
              $ niv modify ${name} -a type=file -a builtin=true'';
  #
  # Various helpers
  #
  # The set of packages used when specs are fetched using non-builtins.
  mkPkgs = sources:
    let
      sourcesNixpkgs =
        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; })
        { };
      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
    in if builtins.hasAttr "nixpkgs" sources then
      sourcesNixpkgs
    else if hasNixpkgsPath && !hasThisAsNixpkgsPath then
      import <nixpkgs> { }
    else
      abort ''
        Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
        add a package called "nixpkgs" to your sources.json.
      '';
  # The actual fetching function.
  fetch = pkgs: name: spec:
    if !builtins.hasAttr "type" spec then
      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
    else if spec.type == "file" then
      fetch_file pkgs spec
    else if spec.type == "tarball" then
      fetch_tarball pkgs name spec
    else if spec.type == "git" then
      fetch_git spec
    else if spec.type == "local" then
      fetch_local spec
    else if spec.type == "builtin-tarball" then
      fetch_builtin-tarball name
    else if spec.type == "builtin-url" then
      fetch_builtin-url name
    else
      abort
      "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
  # Ports of functions for older nix versions
  # a Nix version of mapAttrs if the built-in doesn't exist
  mapAttrs = builtins.mapAttrs or (f: set:
    with builtins;
    listToAttrs (map (attr: {
      name = attr;
      value = f attr set.${attr};
    }) (attrNames set)));
  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
  range = first: last:
    if first > last then
      [ ]
    else
      builtins.genList (n: first + n) (last - first + 1);
  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
  stringToCharacters = s:
    map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
  concatStrings = builtins.concatStringsSep "";
  # fetchTarball version that is compatible between all the versions of Nix
  builtins_fetchTarball = { url, name, sha256 }@attrs:
    let inherit (builtins) lessThan nixVersion fetchTarball;
    in if lessThan nixVersion "1.12" then
      fetchTarball { inherit name url; }
    else
      fetchTarball attrs;
  # fetchurl version that is compatible between all the versions of Nix
  builtins_fetchurl = { url, sha256 }@attrs:
    let inherit (builtins) lessThan nixVersion fetchurl;
    in if lessThan nixVersion "1.12" then
      fetchurl { inherit url; }
    else
      fetchurl attrs;
  # Create the final "sources" from the config
  mkSources = config:
    mapAttrs (name: spec:
      if builtins.hasAttr "outPath" spec then
        abort
        "The values in sources.json should not have an 'outPath' attribute"
      else
        spec // { outPath = fetch config.pkgs name spec; }) config.sources;
  # The "config" used by the fetchers
  mkConfig = { sourcesFile ? ./sources.json
    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
    , pkgs ? mkPkgs sources }: rec {
      # The sources, i.e. the attribute set of spec name to spec
      inherit sources;
      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
      inherit pkgs;
    };
in mkSources (mkConfig { }) // {
  __functor = _: settings: mkSources (mkConfig settings);
}

{
    "niv": {
        "branch": "master",
        "description": "Easy dependency management for Nix projects",
        "homepage": "https://github.com/nmattia/niv",
        "owner": "nmattia",
        "repo": "niv",
        "rev": "ba57d5a29b4e0f2085917010380ef3ddc3cf380f",
        "sha256": "1kpsvc53x821cmjg1khvp1nz7906gczq8mp83664cr15h94sh8i4",
        "type": "tarball",
        "url": "https://github.com/nmattia/niv/archive/ba57d5a29b4e0f2085917010380ef3ddc3cf380f.tar.gz",
        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
    },
    "nixpkgs": {
        "branch": "nixos-unstable",
        "description": "Nix Packages collection",
        "homepage": null,
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "a371c1071161104d329f6a85d922fd92b7cbab63",
        "sha256": "1k5wa16wyb1byk5xfjlq4m518gsw6g1kypx4xb09k3inni13p0r4",
        "type": "tarball",
        "url": "https://github.com/NixOS/nixpkgs/archive/a371c1071161104d329f6a85d922fd92b7cbab63.tar.gz",
        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
    },
    "nixpkgs-mozilla": {
        "branch": "master",
        "description": "mozilla related nixpkgs (extends nixos/nixpkgs repo)",
        "homepage": null,
        "owner": "mozilla",
        "repo": "nixpkgs-mozilla",
        "rev": "8c007b60731c07dd7a052cce508de3bb1ae849b4",
        "sha256": "1zybp62zz0h077zm2zmqs2wcg3whg6jqaah9hcl1gv4x8af4zhs6",
        "type": "tarball",
        "url": "https://github.com/mozilla/nixpkgs-mozilla/archive/8c007b60731c07dd7a052cce508de3bb1ae849b4.tar.gz",
        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
    }
}

let
  sources = import ./sources.nix;
  mozilla = import sources.nixpkgs-mozilla;
  nixpkgs = import sources.nixpkgs;
in nixpkgs { overlays = [ mozilla ]; }