const std = @import("std");
const Allocator = std.mem.Allocator;
const json = std.json;

pub fn getInteger(object: json.ObjectMap, name: []const u8) ?i64 {
    const value = object.get(name);
    if (value == null) {
        return null;
    }

    if (value.? != json.Value.integer) {
        return null;
    }

    return value.?.integer;
}

pub fn getIntegerRequired(object: json.ObjectMap, name: []const u8) !i64 {
    return getInteger(object, name) orelse return error.MissingProperty;
}

pub fn getPositiveIntegerRequired(object: json.ObjectMap, name: []const u8) !u64 {
    const value = try getIntegerRequired(object, name);
    if (value < 0) {
        return error.InvalidInteger;
    }

    return @intCast(value);
}

pub fn asObject(value: json.Value) ?json.ObjectMap {
    if (value != json.Value.object) {
        return null;
    }

    return value.object;
}

pub fn asArray(value: json.Value) ?json.Array {
    if (value != json.Value.array) {
        return null;
    }

    return value.array;
}

pub fn getObject(object: json.ObjectMap, name: []const u8) ?json.ObjectMap {
    const value = object.get(name);
    if (value == null) {
        return null;
    }

    return asObject(value.?);
}

pub fn getArray(object: json.ObjectMap, name: []const u8) ?json.Array {
    const value = object.get(name);
    if (value == null) {
        return null;
    }

    return asArray(value.?);
}

pub fn getString(object: json.ObjectMap, name: []const u8) ?[]const u8 {
    const value = object.get(name);
    if (value == null) {
        return null;
    }

    if (value.? != json.Value.string) {
        return null;
    }

    return value.?.string;
}

pub fn getStringRequired(object: json.ObjectMap, name: []const u8) ![]const u8 {
    return getString(object, name) orelse return error.MissingProperty;
}

pub fn getArrayRequired(object: json.ObjectMap, name: []const u8) !json.Array {
    return getArray(object, name) orelse return error.MissingProperty;
}