const builtin = @import("builtin");
const std = @import("std");
const zfetch = @import("zfetch");
const crypt = @import("crypt.zig");
const config = @import("config");
const encryptionconfig = @import("encryptionconfig");
// const tls = @import("iguanaTLS");

// NGINX config isn't allowing ECDHE-RSA-CHACHA20-POLY1305 on TLS 1.2
// I need:
//
// nginx to allow that
// iguanaTLS to support tls 1.3
// iguanaTLS to support something else, like ECDHE-ECDSA-CHACHA20-POLY1305
// In the meantime, I've allowed use of http, since we're encrypting anyway
const clipboard_url = "http://clippy.lerch.org/work2";
// const clipboard_url = "https://httpbin.org/post";

const Self = @This();

key: *[crypt.key_size]u8,
allocator: std.mem.Allocator,

pub fn init(allocator: std.mem.Allocator) !Self {
    const key = try getKey(allocator);
    return Self{
        .allocator = allocator,
        .key = key,
    };
}

pub fn deinit(self: *Self) void {
    self.allocator.free(self.key);
}

pub fn download(self: *Self) ?[]const u8 {
    const encrypted = get(self.allocator) catch |e| {
        std.log.err("Could not download remote clipboard contents: {}", .{e});
        if (@errorReturnTrace()) |trace| {
            std.debug.dumpStackTrace(trace.*);
        }
        return null;
    };
    defer self.allocator.free(encrypted);
    return crypt.decryptWithKey(self.allocator, self.key.*, encrypted) catch |e| {
        std.log.err("Could not decrypt remote clipboard contents: {}", .{e});
        if (@errorReturnTrace()) |trace| {
            std.debug.dumpStackTrace(trace.*);
        }
        return null;
    };
}

pub fn clipboardChanged(self: *Self, contents: []const u8) !void {
    var arena_allocator = std.heap.ArenaAllocator.init(self.allocator);
    defer arena_allocator.deinit();
    const aa = arena_allocator.allocator();
    const clip_contents = try aa.dupe(u8, contents);
    defer aa.free(clip_contents);

    // Ugh - it's the encryption that Crowdstrike doesn't like.. :(
    var buf: []u8 = try aa.alloc(u8, contents.len);
    defer aa.free(buf);
    std.mem.copy(u8, buf, contents);
    const encrypted = encrypt(aa, self.key.*, buf) catch |e| {
        std.log.err("Could not encrypt clipboard contents: {}", .{e});
        if (@errorReturnTrace()) |trace| {
            std.debug.dumpStackTrace(trace.*);
        }
        return;
    };
    defer aa.free(encrypted);
    put(aa, encrypted) catch |e| {
        std.log.err("error posting clipboard contents {}", .{e});
        if (@errorReturnTrace()) |trace| {
            std.debug.dumpStackTrace(trace.*);
        }
        return;
    };
}

fn encrypt(allocator: std.mem.Allocator, key: [crypt.key_size]u8, data: []u8) ![]const u8 {
    if (encryptionconfig.encryption) |external_encryption| {
        const result = try std.ChildProcess.exec(.{
            .allocator = allocator,
            .argv = &[_][]const u8{
                external_encryption,
                data,
            },
        });
        try std.io.getStdErr().writer().writeAll(result.stderr);
        switch (result.term) {
            .Exited => |code| if (code == 0) {
                return result.stdout;
            } else return error.NonZeroExit,
            .Signal => return error.FailedWithSignal,
            .Stopped => return error.WasStopped,
            .Unknown => return error.Failed,
        }
    }
    return try crypt.encryptWithKey(allocator, key, data);
}

fn getKey(allocator: std.mem.Allocator) !*[crypt.key_size]u8 {
    const passfile = std.fs.cwd().openFile(".clippy", .{}) catch |e| {
        if (e == error.FileNotFound) {
            const cwd = std.fs.realpathAlloc(allocator, ".") catch "could not determine";
            defer allocator.free(cwd);
            std.log.err("Could not find '.clippy' file in directory {s}. Please add a password to this file", .{cwd});
        }
        return e;
    };
    defer passfile.close();
    const pass = try passfile.readToEndAlloc(allocator, std.math.maxInt(usize));
    defer allocator.free(pass);

    const tmp_key = try crypt.keyFromPassword(allocator, pass, ""); // reuse key - this is slow
    return tmp_key;
}

fn get(allocator: std.mem.Allocator) ![]const u8 {
    if (config.curl) |curl|
        return getCurl(allocator, curl);

    // TODO: Windows
    // var cert_reader = std.io.fixedBufferStream(
    //     @embedFile("/etc/ssl/certs/ca-certificates.crt"),
    // ).reader();
    // const trust = try tls.x509.CertificateChain.from_pem(allocator, cert_reader);
    try zfetch.init();
    defer zfetch.deinit();

    var headers = zfetch.Headers.init(allocator);
    defer headers.deinit();

    // try headers.appendValue("Accept", "application/json");
    // try headers.appendValue("Content-Type", "text/plain");

    var req = try zfetch.Request.init(allocator, clipboard_url, null);
    defer req.deinit();

    try req.do(.GET, headers, null);

    // Printf debugging
    // const stdout = std.io.getStdOut().writer();
    // try stdout.print("status: {d} {s}\n", .{ req.status.code, req.status.reason });
    // try stdout.print("headers:\n", .{});
    // for (req.headers.list.items) |header| {
    //     try stdout.print("  {s}: {s}\n", .{ header.name, header.value });
    // }
    // try stdout.print("body:\n", .{});
    //
    const reader = req.reader();

    var data = std.ArrayList(u8).init(allocator);
    defer data.deinit();
    const data_writer = data.writer();
    var buf: [1024]u8 = undefined;
    while (true) {
        const read = try reader.read(&buf);
        if (read == 0) break;

        try data_writer.writeAll(buf[0..read]);
    }
    return data.toOwnedSlice();
}

fn getCurl(allocator: std.mem.Allocator, curl_path: []const u8) ![]const u8 {
    std.log.debug("curl path: {s}", .{curl_path});
    const result = os: {
        if (builtin.os.tag == .linux) {
            const curl_cmd = try std.fmt.allocPrint(allocator, "{s} -s {s}", .{ curl_path, clipboard_url });
            defer allocator.free(curl_cmd);
            break :os try execLinux(allocator, curl_cmd);
        } else if (builtin.os.tag == .windows) {
            break :os try std.ChildProcess.exec(.{
                .allocator = allocator,
                .argv = &[_][]const u8{
                    curl_path, // TODO: use Comspec
                    "-s",
                    clipboard_url,
                },
            });
        } else {
            return error.OsUnsupported;
        }
    };
    try std.io.getStdErr().writer().writeAll(result.stderr);
    switch (result.term) {
        .Exited => |code| if (code == 0) {
            return result.stdout;
        } else return error.NonZeroExit,
        .Signal => return error.FailedWithSignal,
        .Stopped => return error.WasStopped,
        .Unknown => return error.Failed,
    }
}

fn putCurl(allocator: std.mem.Allocator, curl_path: []const u8, data: []const u8) !void {
    std.log.debug("curl path: {s}", .{curl_path});
    std.log.debug("clip url: {s}", .{clipboard_url});
    std.log.debug("data (hex): {s}", .{std.fmt.fmtSliceHexLower(data)});
    std.log.debug("data (string): {s}", .{data});
    const bindata = blk: {
        if (encryptionconfig.temp_file) |tmp_name| {
            const tmp = try std.fs.createFileAbsolute(tmp_name, .{});
            defer tmp.close();
            try tmp.writer().writeAll(data);
            break :blk "@" ++ tmp_name;
        } else {
            break :blk data;
        }
    };
    std.log.debug("bindata: {s}", .{data});
    // binary in args
    const result = try std.ChildProcess.exec(.{
        .allocator = allocator,
        .argv = &[_][]const u8{
            curl_path, // TODO: use Comspec
            "-s",
            "-X",
            "PUT",
            "--data-binary",
            bindata,
            clipboard_url,
        },
    });

    try std.io.getStdErr().writer().writeAll(result.stderr);
    switch (result.term) {
        .Exited => |code| if (code == 0) {
            return;
        } else return error.NonZeroExit,
        .Signal => return error.FailedWithSignal,
        .Stopped => return error.WasStopped,
        .Unknown => return error.Failed,
    }
}

fn execLinux(allocator: std.mem.Allocator, cmd: []const u8) !std.ChildProcess.ExecResult {
    return std.ChildProcess.exec(.{
        .allocator = allocator,
        .argv = &[_][]const u8{
            "/usr/bin/env",
            "sh",
            "-c",
            cmd,
        },
    });
}

// Potentially useful code, but no longer necessary
// fn execWindows(allocator: std.mem.Allocator, cmd: []const u8) !std.ChildProcess.ExecResult {
//     return std.ChildProcess.exec(.{
//         .allocator = allocator,
//         .argv = &[_][]const u8{
//             "c:\\windows\\system32\\cmd.exe", // TODO: use Comspec
//             "/c",
//             cmd,
//         },
//     });
// }

fn put(allocator: std.mem.Allocator, data: []const u8) !void {
    if (config.curl) |curl|
        return putCurl(allocator, curl, data);

    // TODO: Windows
    // var cert_reader = std.io.fixedBufferStream(
    //     @embedFile("/etc/ssl/certs/ca-certificates.crt"),
    // ).reader();
    // const trust = try tls.x509.CertificateChain.from_pem(allocator, cert_reader);
    try zfetch.init();
    defer zfetch.deinit();

    var headers = zfetch.Headers.init(allocator);
    defer headers.deinit();

    // try headers.appendValue("Accept", "application/json");
    // try headers.appendValue("Content-Type", "text/plain");

    var req = try zfetch.Request.init(allocator, clipboard_url, null);
    defer req.deinit();

    try req.do(.PUT, headers, data);

    // Printf debugging
    // const stdout = std.io.getStdOut().writer();
    // try stdout.print("status: {d} {s}\n", .{ req.status.code, req.status.reason });
    // try stdout.print("headers:\n", .{});
    // for (req.headers.list.items) |header| {
    //     try stdout.print("  {s}: {s}\n", .{ header.name, header.value });
    // }
    // try stdout.print("body:\n", .{});
    //
    // const reader = req.reader();
    //
    // var buf: [1024]u8 = undefined;
    // while (true) {
    //     const read = try reader.read(&buf);
    //     if (read == 0) break;
    //
    //     try stdout.writeAll(buf[0..read]);
    // }
}

test "full integration" {
    var allocator = std.testing.allocator;
    var watcher = init(allocator);
    defer watcher.deinit();
    try watcher.clipboardChanged("hello world");
}