const std = @import("std");
const builtin = @import("builtin");
const build_options = @import("build_options");
const yazap = @import("yazap");
const logz = @import("logz");
const Config = @import("config.zig").Config;
const connect = @import("connect.zig");

const App = yazap.App;
const Arg = yazap.Arg;

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    const alloc = gpa.allocator();

    try logz.setup(alloc, .{
        .level = .Debug,
        .pool_size = 16,
        .max_size = 4096,
        .output = .stderr,
    });

    var app = App.init(alloc, "hostapps", "hostapps");
    defer app.deinit();

    var root = app.rootCommand();
    try root.addArg(Arg.booleanOption("version", null, "Print version and exit"));

    var connect_command = app.createCommand("connect", "connect to remote host");
    try connect_command.addArg(Arg.singleValueOption("config", null, "Path to configuration file"));
    try connect_command.addArg(Arg.multiValuesOption("identity", null, "Path to identity file", 8));
    try connect_command.addArg(Arg.singleValueOption("proxy-jump", null, "Proxy jump"));
    try connect_command.addArg(Arg.singleValueOption("ssh-command", null, "Path to ssh command"));
    try connect_command.addArg(Arg.singleValueOption("telnet-command", null, "Path to telnet command"));

    try root.addSubcommand(connect_command);

    const matches = try app.parseProcess();

    if (!(matches.containsArgs())) {
        try app.displayHelp();
        return;
    }

    if (matches.containsArg("version")) {
        std.log.info("version number", .{});
        return;
    }

    if (matches.subcommandMatches("connect")) |connect_matches| {
        const config_path = connect_matches.getSingleValue("config") orelse {
            try app.displaySubcommandHelp();
            return;
        };

        const identities = id: {
            const ids = connect_matches.getMultiValues("identity");
            if (ids != null) break :id ids;
            const id = connect_matches.getSingleValue("identity");
            if (id) |i| {
                break :id @as(?[][]const u8, @constCast(&[_][]const u8{i}));
            }
            break :id null;
        };

        if (identities) |i| {
            for (i) |identity| {
                logz.info().string("identity", identity).log();
                const fullpath = fp: {
                    if (identity[0] == '~') {
                        const home = std.os.getenv("HOME") orelse {
                            logz.err().src(@src()).string("message", "unable to get HOME environment variable to expand tilde").log();
                            return;
                        };
                        var fp = try alloc.alloc(u8, home.len + identity.len - 1);
                        @memcpy(fp[0..home.len], home);
                        @memcpy(fp[home.len..], identity[1..]);
                        break :fp fp;
                    }
                    break :fp identity;
                };
                logz.info().string("fullpath", fullpath).log();
                std.fs.cwd().access(fullpath, .{ .mode = .read_only }) catch |err| {
                    logz.err().src(@src()).err(err).string("identity", identity).string("fullpath", fullpath).log();
                    return;
                };
                if (identity.ptr != fullpath.ptr) alloc.free(fullpath);
            }
        }

        const proxy_jump = connect_matches.getSingleValue("proxy-jump");

        var ssh_path = connect_matches.getSingleValue("ssh-command") orelse build_options.ssh_path;

        if (!std.fs.path.isAbsolute(ssh_path)) {
            const expanded = expandPath(alloc, ssh_path) catch |err| expanded: {
                std.log.warn("failed to expand ssh path={s} err={}", .{ ssh_path, err });
                break :expanded null;
            };
            if (expanded) |v| {
                ssh_path = v;
            }
        }

        var telnet_path = connect_matches.getSingleValue("telnet-command") orelse build_options.telnet_path;

        if (!std.fs.path.isAbsolute(telnet_path)) {
            const expanded = expandPath(alloc, telnet_path) catch |err| expanded: {
                std.log.warn("failed to expand telnet path={s} err={}", .{ telnet_path, err });
                break :expanded null;
            };
            if (expanded) |v| {
                telnet_path = v;
            }
        }

        try connect.connect(alloc, config_path, identities, proxy_jump, ssh_path, telnet_path);

        return;
    }
}

fn expandPath(alloc: std.mem.Allocator, cmd: []const u8) !?[]u8 {
    const PATH = switch (builtin.os.tag) {
        .windows => blk: {
            const win_path = std.os.getenvW(std.unicode.utf8ToUtf16LeStringLiteral("PATH")) orelse return null;
            const path = try std.unicode.utf16leToUtf8Alloc(alloc, win_path);
            break :blk path;
        },
        else => std.os.getenvZ("PATH") orelse return null,
    };
    defer if (builtin.os.tag == .windows) alloc.free(PATH);

    var path_buf: [std.fs.MAX_PATH_BYTES]u8 = undefined;
    var it = std.mem.tokenizeScalar(u8, PATH, std.fs.path.delimiter);
    var seen_eaccess = false;
    while (it.next()) |search_path| {
        const path_len = search_path.len + cmd.len + 1;
        if (path_buf.len < path_len) return error.PathTooLong;

        @memcpy(path_buf[0..search_path.len], search_path);
        path_buf[search_path.len] = std.fs.path.sep;
        @memcpy(path_buf[search_path.len + 1 ..][0..cmd.len], cmd);
        path_buf[path_len] = 0;
        const full_path = path_buf[0..path_len :0];

        const stat = std.fs.cwd().statFile(full_path) catch |err| switch (err) {
            error.FileNotFound => continue,
            error.AccessDenied => {
                seen_eaccess = true;
                continue;
            },
            else => return err,
        };
        if (stat.kind != .directory and isExecutable(stat.mode)) {
            std.log.debug("executable: {s}", .{full_path});
            return try alloc.dupe(u8, full_path);
        }
    }

    if (seen_eaccess) return error.AccessDenied;

    return null;
}

fn isExecutable(mode: std.fs.File.Mode) bool {
    if (builtin.os.tag == .windows) return true;
    return mode & 0o0111 != 0;
}