// Copyright (c) 2017-present The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_RPC_UTIL_H
#define BITCOIN_RPC_UTIL_H

#include <addresstype.h>
#include <consensus/amount.h>
#include <node/transaction.h>
#include <outputtype.h>
#include <pubkey.h>
#include <rpc/protocol.h>
#include <rpc/request.h>
#include <script/script.h>
#include <script/sign.h>
#include <uint256.h>
#include <univalue.h>
#include <util/check.h>

#include <cstddef>
#include <cstdint>
#include <functional>
#include <initializer_list>
#include <map>
#include <optional>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <variant>
#include <vector>

class JSONRPCRequest;
enum ServiceFlags : uint64_t;
enum class OutputType;
struct FlatSigningProvider;
struct bilingual_str;
namespace common {
enum class PSBTError;
} // namespace common
namespace node {
enum class TransactionError;
} // namespace node

static constexpr bool DEFAULT_RPC_DOC_CHECK{
#ifdef RPC_DOC_CHECK
    true
#else
    false
#endif
};

/**
 * String used to describe UNIX epoch time in documentation, factored out to a
 * constant for consistency.
 */
extern const std::string UNIX_EPOCH_TIME;

/**
 * Example bech32 addresses for the RPCExamples help documentation. They are intentionally
 * invalid to prevent accidental transactions by users.
 */
extern const std::string EXAMPLE_ADDRESS[2];

class FillableSigningProvider;
class CScript;
struct Sections;

struct HelpResult : std::runtime_error {
    explicit HelpResult(const std::string& msg) : std::runtime_error{msg} {}
};

/**
 * Gets all existing output types formatted for RPC help sections.
 *
 * @return Comma separated string representing output type names.
 */
std::string GetAllOutputTypes();

/** Wrapper for UniValue::VType, which includes typeAny:
 * Used to denote don't care type. */
struct UniValueType {
    UniValueType(UniValue::VType _type) : typeAny(false), type(_type) {}
    UniValueType() : typeAny(true) {}
    bool typeAny;
    UniValue::VType type;
};

/*
  Check for expected keys/value types in an Object.
*/
void RPCTypeCheckObj(const UniValue& o,
    const std::map<std::string, UniValueType>& typesExpected,
    bool fAllowNull = false,
    bool fStrict = false);

/**
 * Utilities: convert hex-encoded Values
 * (throws error if not hex).
 */
uint256 ParseHashV(const UniValue& v, std::string_view name);
uint256 ParseHashO(const UniValue& o, std::string_view strKey);
std::vector<unsigned char> ParseHexV(const UniValue& v, std::string_view name);
std::vector<unsigned char> ParseHexO(const UniValue& o, std::string_view strKey);

/**
 * Parses verbosity from provided UniValue.
 *
 * @param[in] arg The verbosity argument as an int (0, 1, 2,...) or bool if allow_bool is set to true
 * @param[in] default_verbosity The value to return if verbosity argument is null
 * @param[in] allow_bool If true, allows arg to be a bool and parses it
 * @returns An integer describing the verbosity level (e.g. 0, 1, 2, etc.)
 * @throws JSONRPCError if allow_bool is false but arg provided is boolean
 */
int ParseVerbosity(const UniValue& arg, int default_verbosity, bool allow_bool);

/**
 * Validate and return a CAmount from a UniValue number or string.
 *
 * @param[in] value     UniValue number or string to parse.
 * @param[in] decimals  Number of significant digits (default: 8).
 * @returns a CAmount if the various checks pass.
 */
CAmount AmountFromValue(const UniValue& value, int decimals = 8);
/**
 * Parse a json number or string, denoting BTC/kvB, into a CFeeRate (sat/kvB).
 * Reject negative values or rates larger than 1BTC/kvB.
 */
CFeeRate ParseFeeRate(const UniValue& json);

using RPCArgList = std::vector<std::pair<std::string, UniValue>>;
std::string HelpExampleCli(const std::string& methodname, const std::string& args);
std::string HelpExampleCliNamed(const std::string& methodname, const RPCArgList& args);
std::string HelpExampleRpc(const std::string& methodname, const std::string& args);
std::string HelpExampleRpcNamed(const std::string& methodname, const RPCArgList& args);

CPubKey HexToPubKey(const std::string& hex_in);
CTxDestination AddAndGetMultisigDestination(const int required, const std::vector<CPubKey>& pubkeys, OutputType type, FlatSigningProvider& keystore, CScript& script_out);

UniValue DescribeAddress(const CTxDestination& dest);

/** Parse a sighash string representation and raise an RPC error if it is invalid. */
std::optional<int> ParseSighashString(const UniValue& sighash);

//! Parse a confirm target option and raise an RPC error if it is invalid.
unsigned int ParseConfirmTarget(const UniValue& value, unsigned int max_target);

RPCErrorCode RPCErrorFromTransactionError(node::TransactionError terr);
UniValue JSONRPCPSBTError(common::PSBTError err);
UniValue JSONRPCTransactionError(node::TransactionError terr, const std::string& err_string = "");

//! Parse a JSON range specified as int64, or [int64, int64]
std::pair<int64_t, int64_t> ParseDescriptorRange(const UniValue& value);

/** Evaluate a descriptor given as a string, or as a {"desc":...,"range":...} object, with default range of 1000. */
std::vector<CScript> EvalDescriptorStringOrObject(const UniValue& scanobject, FlatSigningProvider& provider, const bool expand_priv = false);

/**
 * Serializing JSON objects depends on the outer type. Only arrays and
 * dictionaries can be nested in json. The top-level outer type is "NONE".
 */
enum class OuterType {
    ARR,
    OBJ,
    NONE, // Only set on first recursion
};

struct RPCArgOptions {
    bool skip_type_check{false};
    std::string oneline_description{};   //!< Should be empty unless it is supposed to override the auto-generated summary line
    std::vector<std::string> type_str{}; //!< Should be empty unless it is supposed to override the auto-generated type strings. Vector length is either 0 or 2, m_opts.type_str.at(0) will override the type of the value in a key-value pair, m_opts.type_str.at(1) will override the type in the argument description.
    bool hidden{false};                  //!< For testing only
    bool also_positional{false};         //!< If set allows a named-parameter field in an OBJ_NAMED_PARAM options object
                                         //!< to have the same name as a top-level parameter. By default the RPC
                                         //!< framework disallows this, because if an RPC request passes the value by
                                         //!< name, it is assigned to top-level parameter position, not to the options
                                         //!< position, defeating the purpose of using OBJ_NAMED_PARAMS instead OBJ for
                                         //!< that option. But sometimes it makes sense to allow less-commonly used
                                         //!< options to be passed by name only, and more commonly used options to be
                                         //!< passed by name or position, so the RPC framework allows this as long as
                                         //!< methods set the also_positional flag and read values from both positions.
};

// NOLINTNEXTLINE(misc-no-recursion)
struct RPCArg {
    enum class Type {
        OBJ,
        ARR,
        STR,
        NUM,
        BOOL,
        OBJ_NAMED_PARAMS, //!< Special type that behaves almost exactly like
                          //!< OBJ, defining an options object with a list of
                          //!< pre-defined keys. The only difference between OBJ
                          //!< and OBJ_NAMED_PARAMS is that OBJ_NAMED_PARMS
                          //!< also allows the keys to be passed as top-level
                          //!< named parameters, as a more convenient way to pass
                          //!< options to the RPC method without nesting them.
        OBJ_USER_KEYS, //!< Special type where the user must set the keys e.g. to define multiple addresses; as opposed to e.g. an options object where the keys are predefined
        AMOUNT,        //!< Special type representing a floating point amount (can be either NUM or STR)
        STR_HEX,       //!< Special type that is a STR with only hex chars
        RANGE,         //!< Special type that is a NUM or [NUM,NUM]
    };

    enum class Optional {
        /** Required arg */
        NO,
        /**
         * Optional argument for which the default value is omitted from
         * help text for one of two reasons:
         * - It's a named argument and has a default value of `null`.
         * - Its default value is implicitly clear. That is, elements in an
         *    array may not exist by default.
         * When possible, the default value should be specified.
         */
        OMITTED,
    };
    /** Hint for default value */
    using DefaultHint = std::string;
    /** Default constant value */
    using Default = UniValue;
    using Fallback = std::variant<Optional, DefaultHint, Default>;

    const std::string m_names; //!< The name of the arg (can be empty for inner args, can contain multiple aliases separated by | for named request arguments)
    const Type m_type;
    const std::vector<RPCArg> m_inner; //!< Only used for arrays or dicts
    const Fallback m_fallback;
    const std::string m_description;
    const RPCArgOptions m_opts;

    RPCArg(
        std::string name,
        Type type,
        Fallback fallback,
        std::string description,
        RPCArgOptions opts = {})
        : m_names{std::move(name)},
          m_type{std::move(type)},
          m_fallback{std::move(fallback)},
          m_description{std::move(description)},
          m_opts{std::move(opts)}
    {
        CHECK_NONFATAL(type != Type::ARR && type != Type::OBJ && type != Type::OBJ_NAMED_PARAMS && type != Type::OBJ_USER_KEYS);
    }

    RPCArg(
        std::string name,
        Type type,
        Fallback fallback,
        std::string description,
        std::vector<RPCArg> inner,
        RPCArgOptions opts = {})
        : m_names{std::move(name)},
          m_type{std::move(type)},
          m_inner{std::move(inner)},
          m_fallback{std::move(fallback)},
          m_description{std::move(description)},
          m_opts{std::move(opts)}
    {
        CHECK_NONFATAL(type == Type::ARR || type == Type::OBJ || type == Type::OBJ_NAMED_PARAMS || type == Type::OBJ_USER_KEYS);
    }

    bool IsOptional() const;

    /**
     * Check whether the request JSON type matches.
     * Returns true if type matches, or object describing error(s) if not.
     */
    UniValue MatchesType(const UniValue& request) const;

    /** Return the first of all aliases */
    std::string GetFirstName() const;

    /** Return the name, throws when there are aliases */
    std::string GetName() const;

    /**
     * Return the type string of the argument.
     * Set oneline to allow it to be overridden by a custom oneline type string (m_opts.oneline_description).
     */
    std::string ToString(bool oneline) const;
    /**
     * Return the type string of the argument when it is in an object (dict).
     * Set oneline to get the oneline representation (less whitespace)
     */
    std::string ToStringObj(bool oneline) const;
    /**
     * Return the description string, including the argument type and whether
     * the argument is required.
     */
    std::string ToDescriptionString(bool is_named_arg) const;
};

// NOLINTNEXTLINE(misc-no-recursion)
struct RPCResult {
    enum class Type {
        OBJ,
        ARR,
        STR,
        NUM,
        BOOL,
        NONE,
        ANY,        //!< Special type to disable type checks (for testing only)
        STR_AMOUNT, //!< Special string to represent a floating point amount
        STR_HEX,    //!< Special string with only hex chars
        OBJ_DYN,    //!< Special dictionary with keys that are not literals
        ARR_FIXED,  //!< Special array that has a fixed number of entries
        NUM_TIME,   //!< Special numeric to denote unix epoch time
        ELISION,    //!< Special type to denote elision (...)
    };

    const Type m_type;
    const std::string m_key_name;         //!< Only used for dicts
    const std::vector<RPCResult> m_inner; //!< Only used for arrays or dicts
    const bool m_optional;
    const bool m_skip_type_check;
    const std::string m_description;
    const std::string m_cond;

    RPCResult(
        std::string cond,
        Type type,
        std::string m_key_name,
        bool optional,
        std::string description,
        std::vector<RPCResult> inner = {})
        : m_type{std::move(type)},
          m_key_name{std::move(m_key_name)},
          m_inner{std::move(inner)},
          m_optional{optional},
          m_skip_type_check{false},
          m_description{std::move(description)},
          m_cond{std::move(cond)}
    {
        CHECK_NONFATAL(!m_cond.empty());
        CheckInnerDoc();
    }

    RPCResult(
        std::string cond,
        Type type,
        std::string m_key_name,
        std::string description,
        std::vector<RPCResult> inner = {})
        : RPCResult{std::move(cond), type, std::move(m_key_name), /*optional=*/false, std::move(description), std::move(inner)} {}

    RPCResult(
        Type type,
        std::string m_key_name,
        bool optional,
        std::string description,
        std::vector<RPCResult> inner = {},
        bool skip_type_check = false)
        : m_type{std::move(type)},
          m_key_name{std::move(m_key_name)},
          m_inner{std::move(inner)},
          m_optional{optional},
          m_skip_type_check{skip_type_check},
          m_description{std::move(description)},
          m_cond{}
    {
        CheckInnerDoc();
    }

    RPCResult(
        Type type,
        std::string m_key_name,
        std::string description,
        std::vector<RPCResult> inner = {},
        bool skip_type_check = false)
        : RPCResult{type, std::move(m_key_name), /*optional=*/false, std::move(description), std::move(inner), skip_type_check} {}

    /** Append the sections of the result. */
    void ToSections(Sections& sections, OuterType outer_type = OuterType::NONE, const int current_indent = 0) const;
    /** Return the type string of the result when it is in an object (dict). */
    std::string ToStringObj() const;
    /** Return the description string, including the result type. */
    std::string ToDescriptionString() const;
    /** Check whether the result JSON type matches.
     * Returns true if type matches, or object describing error(s) if not.
     */
    UniValue MatchesType(const UniValue& result) const;

private:
    void CheckInnerDoc() const;
};

struct RPCResults {
    const std::vector<RPCResult> m_results;

    RPCResults(RPCResult result)
        : m_results{{result}}
    {
    }

    RPCResults(std::initializer_list<RPCResult> results)
        : m_results{results}
    {
    }

    /**
     * Return the description string.
     */
    std::string ToDescriptionString() const;
};

struct RPCExamples {
    const std::string m_examples;
    explicit RPCExamples(
        std::string examples)
        : m_examples(std::move(examples))
    {
    }
    std::string ToDescriptionString() const;
};

class RPCHelpMan
{
public:
    RPCHelpMan(std::string name, std::string description, std::vector<RPCArg> args, RPCResults results, RPCExamples examples);
    using RPCMethodImpl = std::function<UniValue(const RPCHelpMan&, const JSONRPCRequest&)>;
    RPCHelpMan(std::string name, std::string description, std::vector<RPCArg> args, RPCResults results, RPCExamples examples, RPCMethodImpl fun);

    UniValue HandleRequest(const JSONRPCRequest& request) const;
    /**
     * @brief Helper to get a required or default-valued request argument.
     *
     * Use this function when the argument is required or when it has a default value. If the
     * argument is optional and may not be provided, use MaybeArg instead.
     *
     * This function only works during m_fun(), i.e., it should only be used in
     * RPC method implementations. It internally checks whether the user-passed
     * argument isNull() and parses (from JSON) and returns the user-passed argument,
     * or the default value derived from the RPCArg documentation.
     *
     * The instantiation of this helper for type R must match the corresponding RPCArg::Type.
     *
     * @return The value of the RPC argument (or the default value) cast to type R.
     *
     * @see MaybeArg for handling optional arguments without default values.
     */
    template <typename R>
    auto Arg(std::string_view key) const
    {
        auto i{GetParamIndex(key)};
        // Return argument (required or with default value).
        if constexpr (std::is_integral_v<R> || std::is_floating_point_v<R>) {
            // Return numbers by value.
            return ArgValue<R>(i);
        } else {
            // Return everything else by reference.
            return ArgValue<const R&>(i);
        }
    }
    /**
     * @brief Helper to get an optional request argument.
     *
     * Use this function when the argument is optional and does not have a default value. If the
     * argument is required or has a default value, use Arg instead.
     *
     * This function only works during m_fun(), i.e., it should only be used in
     * RPC method implementations. It internally checks whether the user-passed
     * argument isNull() and parses (from JSON) and returns the user-passed argument,
     * or a falsy value if no argument was passed.
     *
     * The instantiation of this helper for type R must match the corresponding RPCArg::Type.
     *
     * @return For integral and floating-point types, a std::optional<R> is returned.
     *         For other types, a R* pointer to the argument is returned. If the
     *         argument is not provided, std::nullopt or a null pointer is returned.
     *
     * @see Arg for handling arguments that are required or have a default value.
     */
    template <typename R>
    auto MaybeArg(std::string_view key) const
    {
        auto i{GetParamIndex(key)};
        // Return optional argument (without default).
        if constexpr (std::is_integral_v<R> || std::is_floating_point_v<R>) {
            // Return numbers by value, wrapped in optional.
            return ArgValue<std::optional<R>>(i);
        } else {
            // Return other types by pointer.
            return ArgValue<const R*>(i);
        }
    }
    std::string ToString() const;
    /** Return the named args that need to be converted from string to another JSON type */
    UniValue GetArgMap() const;
    /** If the supplied number of args is neither too small nor too high */
    bool IsValidNumArgs(size_t num_args) const;
    //! Return list of arguments and whether they are named-only.
    std::vector<std::pair<std::string, bool>> GetArgNames() const;

    const std::string m_name;

private:
    const RPCMethodImpl m_fun;
    const std::string m_description;
    const std::vector<RPCArg> m_args;
    const RPCResults m_results;
    const RPCExamples m_examples;
    mutable const JSONRPCRequest* m_req{nullptr}; // A pointer to the request for the duration of m_fun()
    template <typename R>
    R ArgValue(size_t i) const;
    //! Return positional index of a parameter using its name as key.
    size_t GetParamIndex(std::string_view key) const;
};

/**
 * Push warning messages to an RPC "warnings" field as a JSON array of strings.
 *
 * @param[in] warnings  Warning messages to push.
 * @param[out] obj      UniValue object to push the warnings array object to.
 */
void PushWarnings(const UniValue& warnings, UniValue& obj);
void PushWarnings(const std::vector<bilingual_str>& warnings, UniValue& obj);

std::vector<RPCResult> ScriptPubKeyDoc();

/***
 * Get the target for a given block index.
 *
 * @param[in] blockindex    the block
 * @param[in] pow_limit     PoW limit (consensus parameter)
 *
 * @return  the target
 */
uint256 GetTarget(const CBlockIndex& blockindex, const uint256 pow_limit);

#endif // BITCOIN_RPC_UTIL_H
