// `alvin` - command-line front end to the library, handy for trying backends
// and scripting simple automations.

#include <cstdio>
#include <cstdlib>
#include <filesystem>
#include <fstream>
#include <iostream>
#include <span>
#include <string>
#include <vector>

#include "alvin/alvin.hpp"
#ifdef ALVIN_CLI_VISION
#include "alvin/vision.hpp"
#endif

namespace fs = std::filesystem;
using namespace alvin;

namespace {

void usage() {
    std::cerr <<
        R"(usage: alvin [--input wlr|libei|uinput|sendinput] <command> [args]

  monitors                      list monitors (logical desktop coordinates)
  windows                       list top-level windows
  active                        show the focused window
  focus <text>                  focus the first window whose title/class contains <text>

  move <x> <y>                  move the pointer to desktop coordinates
  moveby <dx> <dy>              move the pointer relatively
  click [left|right|middle] [n] click n times (default: left, 1)
  clickat <x> <y> [button]      move, then click
  scroll <dy> [dx]              scroll wheel notches (positive = down/right)
  key <chord>                   press a chord, e.g. ctrl+shift+t
  type <text>                   type UTF-8 text

  capture <out.ppm|png> [--window] [--cursor]
                                save one frame; the portal token is cached so
                                the picker only appears the first time
)"
#ifdef ALVIN_CLI_VISION
        R"(  find <template.png> [threshold]
                                locate an image on screen, print desktop coords
)"
#endif
        ;
}

int report(const Error& e) {
    std::cerr << "alvin: " << toString(e.code) << ": " << e.message << '\n';
    return 1;
}

int report(const Status& s) { return s ? 0 : report(s.error()); }

std::optional<int> toInt(const std::string& s) {
    try {
        std::size_t used = 0;
        int v = std::stoi(s, &used);
        if (used == s.size()) return v;
    } catch (...) {
    }
    return std::nullopt;
}

std::optional<MouseButton> toButton(const std::string& s) {
    if (s == "left") return MouseButton::Left;
    if (s == "right") return MouseButton::Right;
    if (s == "middle") return MouseButton::Middle;
    if (s == "back") return MouseButton::Back;
    if (s == "forward") return MouseButton::Forward;
    return std::nullopt;
}

fs::path tokenFile(const char* name) {
    const char* cache = std::getenv("XDG_CACHE_HOME");
    const char* home = std::getenv("HOME");
    fs::path dir = cache && *cache ? fs::path(cache) : fs::path(home ? home : ".") / ".cache";
    return dir / "alvin" / name;
}

std::string readToken(const fs::path& p) {
    std::ifstream f(p);
    std::string t;
    std::getline(f, t);
    return t;
}

void writeToken(const fs::path& p, const std::string& token) {
    if (token.empty()) return;
    std::error_code ec;
    fs::create_directories(p.parent_path(), ec);
    std::ofstream(p) << token << '\n';
}

void printWindow(const WindowInfo& w) {
    std::printf("%#llx  %5d,%-5d %5dx%-5d %s%s[%s] %s\n", static_cast<unsigned long long>(w.id.value), w.bounds.x,
                w.bounds.y, w.bounds.width, w.bounds.height, w.focused ? "* " : "  ", w.minimized ? "(min) " : "",
                w.appId.c_str(), w.title.c_str());
}

Result<std::unique_ptr<Input>> makeInput(const InputOptions& base) {
    InputOptions opts = base;
    fs::path tf = tokenFile("remotedesktop.token");
    opts.restoreToken = readToken(tf);
    auto in = Input::create(opts);
    if (in) {
        writeToken(tf, (*in)->restoreToken());
        if (std::getenv("ALVIN_VERBOSE")) std::cerr << "input backend: " << toString((*in)->backend()) << '\n';
    }
    return in;
}

Result<Frame> captureFrame(bool window, bool cursor) {
    CaptureOptions opts;
    opts.source = window ? CaptureSource::Window : CaptureSource::Monitor;
    opts.showCursor = cursor;
    fs::path tf = tokenFile(window ? "screencast-window.token" : "screencast-monitor.token");
    opts.restoreToken = readToken(tf);
    auto cap = Capture::create(opts);
    if (!cap) return std::unexpected(cap.error());
    writeToken(tf, (*cap)->restoreToken());
    return (*cap)->grab();
}

int run(std::span<const std::string> args, const InputOptions& inputOpts) {
    const std::string& cmd = args[0];
    auto arg = [&](std::size_t i) -> const std::string& {
        static const std::string empty;
        return i < args.size() ? args[i] : empty;
    };

    if (cmd == "monitors") {
        auto mons = listMonitors();
        if (!mons) return report(mons.error());
        for (const auto& m : *mons)
            std::printf("%-10s %5d,%-5d %5dx%-5d  pixels %dx%d  scale %.3g%s  %s\n", m.name.c_str(), m.bounds.x,
                        m.bounds.y, m.bounds.width, m.bounds.height, m.pixelSize.width, m.pixelSize.height, m.scale,
                        m.primary ? " (primary)" : "", m.description.c_str());
        return 0;
    }

    if (cmd == "windows" || cmd == "active" || cmd == "focus") {
        auto wm = WindowManager::create();
        if (!wm) return report(wm.error());
        if (cmd == "windows") {
            auto list = (*wm)->list();
            if (!list) return report(list.error());
            for (const auto& w : *list) printWindow(w);
            return 0;
        }
        if (cmd == "active") {
            auto a = (*wm)->active();
            if (!a) return report(a.error());
            if (*a) printWindow(**a);
            return 0;
        }
        auto w = (*wm)->find(arg(1));
        if (!w) return report(w.error());
        if (!*w) return report(Error{ErrorCode::NotFound, "no window matches '" + arg(1) + "'"});
        return report((*wm)->focus((*w)->id));
    }

    if (cmd == "capture") {
        if (arg(1).empty()) return usage(), 2;
        bool window = false, cursor = false;
        for (std::size_t i = 2; i < args.size(); ++i) {
            if (args[i] == "--window") window = true;
            else if (args[i] == "--cursor") cursor = true;
        }
        auto frame = captureFrame(window, cursor);
        if (!frame) return report(frame.error());
        fs::path out = arg(1);
        Status saved;
#ifdef ALVIN_CLI_VISION
        if (out.extension() != ".ppm") saved = vision::saveImage(*frame, out);
        else
#endif
            saved = frame->savePpm(out);
        if (!saved) return report(saved);
        Rect r = frame->desktopRect();
        std::printf("%s: %dx%d pixels, desktop rect %d,%d %dx%d\n", out.c_str(), frame->width(), frame->height(), r.x,
                    r.y, r.width, r.height);
        return 0;
    }

#ifdef ALVIN_CLI_VISION
    if (cmd == "find") {
        auto tpl = vision::loadImage(arg(1));
        if (!tpl) return report(tpl.error());
        vision::MatchOptions mo;
        if (!arg(2).empty()) mo.threshold = std::stod(arg(2));
        auto frame = captureFrame(false, false);
        if (!frame) return report(frame.error());
        auto match = vision::find(*frame, *tpl, mo);
        if (!match) return report(match.error());
        if (!*match) {
            std::printf("not found\n");
            return 1;
        }
        Point c = frame->toDesktop((*match)->rect.center());
        std::printf("%d %d  (score %.3f)\n", c.x, c.y, (*match)->score);
        return 0;
    }
#endif

    // Everything below needs an input backend.
    auto input = makeInput(inputOpts);
    if (!input) return report(input.error());
    Input& in = **input;

    if (cmd == "move" || cmd == "moveby" || cmd == "clickat") {
        auto x = toInt(arg(1)), y = toInt(arg(2));
        if (!x || !y) return usage(), 2;
        if (cmd == "moveby") return report(in.moveBy(*x, *y));
        if (cmd == "move") return report(in.moveTo({*x, *y}));
        auto b = arg(3).empty() ? std::optional{MouseButton::Left} : toButton(arg(3));
        if (!b) return usage(), 2;
        return report(in.clickAt({*x, *y}, *b));
    }
    if (cmd == "click") {
        auto b = arg(1).empty() ? std::optional{MouseButton::Left} : toButton(arg(1));
        auto n = arg(2).empty() ? std::optional{1} : toInt(arg(2));
        if (!b || !n) return usage(), 2;
        return report(in.click(*b, *n));
    }
    if (cmd == "scroll") {
        auto dy = toInt(arg(1));
        auto dx = arg(2).empty() ? std::optional{0} : toInt(arg(2));
        if (!dy || !dx) return usage(), 2;
        return report(in.scroll(*dx, *dy));
    }
    if (cmd == "key") return report(in.chord(std::string_view(arg(1))));
    if (cmd == "type") return report(in.typeText(arg(1)));

    usage();
    return 2;
}

}  // namespace

int main(int argc, char** argv) {
    std::vector<std::string> args(argv + 1, argv + argc);
    InputOptions inputOpts;
    if (args.size() >= 2 && args[0] == "--input") {
        const std::string& b = args[1];
        if (b == "wlr") inputOpts.backend = InputBackend::WlrVirtual;
        else if (b == "libei") inputOpts.backend = InputBackend::LibEi;
        else if (b == "uinput") inputOpts.backend = InputBackend::UInput;
        else if (b == "sendinput") inputOpts.backend = InputBackend::SendInput;
        else return usage(), 2;
        args.erase(args.begin(), args.begin() + 2);
    }
    if (args.empty() || args[0] == "-h" || args[0] == "--help") {
        usage();
        return args.empty() ? 2 : 0;
    }
    return run(args, inputOpts);
}