const std = @import("std");

/// Decode a base64 string, used for parsing out build artifacts generated by the CLI program's
/// build.zig which are stored in the executable as a module.
pub fn base64Decode(allocator: std.mem.Allocator, input: []const u8) ![]const u8 {
    const decoder = std.base64.Base64Decoder.init(
        std.base64.url_safe_no_pad.alphabet_chars,
        std.base64.url_safe_no_pad.pad_char,
    );
    const size = try decoder.calcSizeForSlice(input);
    const ptr = try allocator.alloc(u8, size);
    try decoder.decode(ptr, input);
    return ptr;
}

/// Print a success confirmation.
pub fn printSuccess() void {
    std.debug.print(" ✅\n", .{});
}

/// Print a failure confirmation.
pub fn printFailure() void {
    std.debug.print(" ❌\n", .{});
}

/// Verifies that cwd is the root of a Jetzig project
pub fn detectJetzigProjectDir() !std.fs.Dir {
    var dir = try std.fs.cwd().openDir(".", .{});
    const max_parent_dirs: usize = 100; // Prevent symlink loops or other weird stuff.

    for (0..max_parent_dirs) |_| {
        if (try isPath(dir, "build.zig", .file) and try isPath(dir, "src/app/views", .dir)) return dir;

        dir = dir.openDir("..", .{}) catch |err| {
            switch (err) {
                error.FileNotFound, error.NotDir => {
                    std.debug.print(
                        "Encountered unexpected detecting Jetzig project directory: {s}\n",
                        .{@errorName(err)},
                    );
                    return error.JetzigCommandError;
                },
                else => return err,
            }
        };
        continue;
    }

    std.debug.print(
        \\Exceeded maximum parent directory depth.
        \\Unable to detect Jetzig project directory.
        \\
    ,
        .{},
    );
    return error.JetzigCommandError;
}

fn isPath(dir: std.fs.Dir, sub_path: []const u8, path_type: enum { file, dir }) !bool {
    switch (path_type) {
        .file => {
            _ = dir.statFile(sub_path) catch |err| {
                switch (err) {
                    error.FileNotFound => return false,
                    else => return err,
                }
            };
            return true;
        },
        .dir => {
            var test_dir = dir.openDir(sub_path, .{}) catch |err| {
                switch (err) {
                    error.FileNotFound, error.NotDir => return false,
                    else => return err,
                }
            };
            test_dir.close();
            return true;
        },
    }
}

// Strip leading and trailing whitespace from a u8 slice.
pub fn strip(input: []const u8) []const u8 {
    return std.mem.trim(u8, input, &std.ascii.whitespace);
}

/// Attempts to confirm if a string input is in CamelCase. False if the first character is
/// not alphabetic lower-case or if the input contains underscores.
pub fn isCamelCase(input: []const u8) bool {
    if (input.len == 0) return false;
    if (!std.mem.containsAtLeast(u8, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1, &[_]u8{input[0]})) return false;
    if (std.mem.containsAtLeast(u8, input, 1, "_")) return false;

    return true;
}