/* This file is part of DarkFi (https://dark.fi)
 *
 * Copyright (C) 2020-2025 Dyne.org foundation
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

use std::{collections::HashMap, str::FromStr};

use darkfi::{
    blockchain::{
        header_store::PowData,
        monero::{
            extract_aux_merkle_root_from_block,
            fixed_array::{FixedByteArray, MaxSizeVec},
            merkle_proof::MerkleProof,
            monero_block_deserialize, MoneroPowData,
        },
        HeaderHash,
    },
    rpc::jsonrpc::{ErrorCode, ErrorCode::InvalidParams, JsonError, JsonResponse, JsonResult},
    validator::consensus::Proposal,
};
use darkfi_sdk::crypto::PublicKey;
use hex::FromHex;
use tinyjson::JsonValue;
use tracing::{error, info};

use crate::{
    proto::ProposalMessage,
    task::miner::{generate_next_block, MinerRewardsRecipientConfig},
    DarkfiNode,
};

// https://github.com/SChernykh/p2pool/blob/master/docs/MERGE_MINING.MD

impl DarkfiNode {
    // RPCAPI:
    // Gets a unique ID that identifies this merge mined chain and
    // separates it from other chains.
    //
    // * `chain_id`: A unique 32-byte hex-encoded value that identifies
    //   this merge mined chain.
    //
    // darkfid will send the hash of the genesis block header.
    //
    // --> {"jsonrpc":"2.0", "method": "merge_mining_get_chain_id", "id": 1}
    // <-- {"jsonrpc":"2.0", "result": {"chain_id": "0f28c...7863"}, "id": 1}
    pub async fn xmr_merge_mining_get_chain_id(&self, id: u16, _params: JsonValue) -> JsonResult {
        let (_, genesis_hash) = match self.validator.blockchain.genesis() {
            Ok(v) => v,
            Err(e) => {
                error!(
                    target: "darkfid::rpc::xmr_merge_mining_get_chain_id",
                    "[RPC-XMR] Error fetching genesis block hash: {e}"
                );
                return JsonError::new(ErrorCode::InternalError, None, id).into()
            }
        };

        // TODO: XXX: This should also have more specialized identifiers.
        // e.g. chain_id = H(genesis || aux_nonce || checkpoint_height)

        let response =
            HashMap::from([("chain_id".to_string(), JsonValue::from(genesis_hash.to_string()))]);
        JsonResponse::new(JsonValue::from(response), id).into()
    }

    // RPCAPI:
    // Gets a blob of data (usually a new block for the merge mined chain)
    // and its hash to be used for merge mining.
    //
    // **Request:**
    // * `address` - A wallet address on the merge mined chain
    // * `aux_hash` - Merge mining job that is currently being used
    // * `height` - Monero height
    // * `prev_id` - Hash of the previous Monero block
    //
    // **Response:**
    // * `aux_blob` - A hex-encoded blob of data. Merge mined chain defines the
    //   contents of this blob. It's opaque to p2pool and will not be changed by it
    // * `aux_diff` - Mining difficulty (decimal number)
    // * `aux_hash` - A 32-byte hex-encoded hash of the `aux_blob`. Merge mined chain
    //   defines how exactly this hash is calculated. It's opaque to p2pool.
    //
    // --> {"jsonrpc":"2.0", "method": "merge_mining_get_aux_block", "params": {"address": "MERGE_MINED_CHAIN_ADDRESS", "aux_hash": "f6952d6eef555ddd87aca66e56b91530222d6e318414816f3ba7cf5bf694bf0f", "height": 3000000, "prev_id":"ad505b0be8a49b89273e307106fa42133cbd804456724c5e7635bd953215d92a"}, "id": 1}
    // <-- {"jsonrpc":"2.0", "result": {"aux_blob": "4c6f72656d20697073756d", "aux_diff": 123456, "aux_hash":"f6952d6eef555ddd87aca66e56b91530222d6e318414816f3ba7cf5bf694bf0f"}, "id": 1}
    pub async fn xmr_merge_mining_get_aux_block(&self, id: u16, params: JsonValue) -> JsonResult {
        let Some(params) = params.get::<HashMap<String, JsonValue>>() else {
            return JsonError::new(InvalidParams, None, id).into()
        };

        // Validate address
        let Some(address) = params.get("address") else {
            return JsonError::new(InvalidParams, Some("missing address".to_string()), id).into()
        };
        let Some(address) = address.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid address format".to_string()), id)
                .into()
        };
        let Ok(address) = PublicKey::from_str(address) else {
            return JsonError::new(InvalidParams, Some("invalid address format".to_string()), id)
                .into()
        };

        // Validate aux_hash
        let Some(aux_hash) = params.get("aux_hash") else {
            return JsonError::new(InvalidParams, Some("missing aux_hash".to_string()), id).into()
        };
        let Some(aux_hash) = aux_hash.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid aux_hash format".to_string()), id)
                .into()
        };
        let Ok(aux_hash) = HeaderHash::from_str(aux_hash) else {
            return JsonError::new(InvalidParams, Some("invalid aux_hash format".to_string()), id)
                .into()
        };

        // Validate height
        let Some(height) = params.get("height") else {
            return JsonError::new(InvalidParams, Some("missing height".to_string()), id).into()
        };
        let Some(height) = height.get::<f64>() else {
            return JsonError::new(InvalidParams, Some("invalid height format".to_string()), id)
                .into()
        };
        let height = *height as u64;

        // Validate prev_id
        let Some(prev_id) = params.get("prev_id") else {
            return JsonError::new(InvalidParams, Some("missing prev_id".to_string()), id).into()
        };
        let Some(prev_id) = prev_id.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid prev_id format".to_string()), id)
                .into()
        };
        let Ok(prev_id) = hex::decode(prev_id) else {
            return JsonError::new(InvalidParams, Some("invalid prev_id format".to_string()), id)
                .into()
        };
        let prev_id = monero::Hash::from_slice(&prev_id);

        info!(
            target: "darkfid::rpc_xmr::xmr_merge_mining_get_aux_block",
            "[RPC-XMR] Got blocktemplate request: address={}, aux_hash={}, height={}, prev_id={}",
            address, aux_hash, height, prev_id,
        );

        // Method params format is correct. Let's check if we provided this
        // mining job already. If so, we can just return an empty response.
        // We'll also obtain a lock here to avoid getting polled multiple
        // times and potentially missing a job. The lock is released when
        // this function exits.
        let mut mm_blocktemplates = self.mm_blocktemplates.lock().await;
        if mm_blocktemplates.contains_key(&aux_hash) {
            return JsonResponse::new(JsonValue::from(HashMap::new()), id).into()
        }

        // If it's a new job, clear the previous one(s).
        mm_blocktemplates.clear();

        // At this point, we should query the Validator for a new blocktemplate.
        // We first need to construct `MinerRewardsRecipientConfig` from the
        // address provided to us through the RPC.
        let recipient_config =
            MinerRewardsRecipientConfig { recipient: address, spend_hook: None, user_data: None };

        // Now let's try to construct the blocktemplate.
        let mut extended_fork = match self.best_current_fork().await {
            Ok(f) => f,
            Err(e) => {
                error!(
                    target: "darkfid::rpc_xmr::xmr_merge_mining_get_aux_block",
                    "[RPC-XMR] Finding best fork index failed: {e}",
                );
                return JsonError::new(ErrorCode::InternalError, None, id).into()
            }
        };

        // Find the difficulty. Note we cast it to f64 here.
        let difficulty: f64 = match extended_fork.module.next_difficulty() {
            Ok(v) => {
                // We will attempt to cast it to f64. This should always work.
                v.to_string().parse().unwrap()
            }
            Err(e) => {
                error!(
                    target: "darkfid::rpc_xmr::xmr_merge_mining_get_aux_block",
                    "[RPC-XMR] Finding next mining difficulty failed: {e}",
                );
                return JsonError::new(ErrorCode::InternalError, None, id).into()
            }
        };

        let (_, blocktemplate, block_signing_secret) = match generate_next_block(
            &mut extended_fork,
            &recipient_config,
            &self.powrewardv1_zk.zkbin,
            &self.powrewardv1_zk.provingkey,
            self.validator.consensus.module.read().await.target,
            self.validator.verify_fees,
        )
        .await
        {
            Ok(v) => v,
            Err(e) => {
                error!(
                    target: "darkfid::rpc_xmr::xmr_merge_mining_get_aux_block",
                    "[RPC-XMR] Failed to generate next blocktemplate: {e}",
                );
                return JsonError::new(ErrorCode::InternalError, None, id).into()
            }
        };

        // Now we have the blocktemplate. We'll mark it down in memory,
        // and then ship it to RPC.
        let blockhash = blocktemplate.header.template_hash();
        mm_blocktemplates.insert(blockhash, (blocktemplate, block_signing_secret));

        let response = JsonValue::from(HashMap::from([
            ("aux_blob".to_string(), JsonValue::from(blockhash.as_string())),
            ("aux_diff".to_string(), JsonValue::from(difficulty)),
            ("aux_hash".to_string(), JsonValue::from(blockhash.as_string())),
        ]));

        info!("<-- {}", response.stringify().unwrap());

        JsonResponse::new(response, id).into()
    }

    // RPCAPI:
    // Submits a PoW solution for the merge mined chain's block. Note that
    // when merge mining with Monero, the PoW solution is always a Monero
    // block template with merge mining data included into it.
    //
    // **Request:**
    // * `aux_blob`: Blob of data returned by `merge_mining_get_aux_block`
    // * `aux_hash`: A 32-byte hex-encoded hash of the `aux_blob`, same as above.
    // * `blob`: Monero block template that has enough PoW to satisfy the difficulty
    //   returned by `merge_mining_get_aux_block`. It must also have a merge mining
    //   tag in `tx_extra` of the coinbase transaction.
    // * `merkle_proof`: A proof that `aux_hash` was included when calculating the
    //   Merkle root hash from the merge mining tag
    // * `path`: A path bitmap (32-bit unsigned integer) that complements `merkle_proof`
    // * `seed_hash`: A 32-byte hex-encoded key that is used to initialize the
    //   RandomX dataset
    //
    // **Response:**
    // * `status`: Block submit status
    //
    // --> {"jsonrpc":"2.0", "method": "merge_mining_submit_solution", "params": {"aux_blob": "4c6f72656d20697073756d", "aux_hash": "f6952d6eef555ddd87aca66e56b91530222d6e318414816f3ba7cf5bf694bf0f", "blob": "...", "merkle_proof": ["hash1", "hash2", "hash3"], "path": 3, "seed_hash": "22c3d47c595ae888b5d7fc304235f92f8854644d4fad38c5680a5d4a81009fcd"}, "id": 1}
    // <-- {"jsonrpc":"2.0", "result": {"status": "accepted"}, "id": 1}
    pub async fn xmr_merge_mining_submit_solution(&self, id: u16, params: JsonValue) -> JsonResult {
        let Some(params) = params.get::<HashMap<String, JsonValue>>() else {
            return JsonError::new(InvalidParams, None, id).into()
        };

        // Validate aux_blob
        let Some(aux_blob) = params.get("aux_blob") else {
            return JsonError::new(InvalidParams, Some("missing aux_blob".to_string()), id).into()
        };
        let Some(aux_blob) = aux_blob.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid aux_blob format".to_string()), id)
                .into()
        };
        let Ok(_aux_blob) = HeaderHash::from_str(aux_blob) else {
            return JsonError::new(InvalidParams, Some("invalid aux_blob format".to_string()), id)
                .into()
        };

        // Validate aux_hash
        let Some(aux_hash) = params.get("aux_hash") else {
            return JsonError::new(InvalidParams, Some("missing aux_hash".to_string()), id).into()
        };
        let Some(aux_hash) = aux_hash.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid aux_hash format".to_string()), id)
                .into()
        };
        let Ok(aux_hash) = HeaderHash::from_str(aux_hash) else {
            return JsonError::new(InvalidParams, Some("invalid aux_hash format".to_string()), id)
                .into()
        };

        // If we don't know about this `aux_hash`, we can just abort here.
        let mut mm_blocktemplates = self.mm_blocktemplates.lock().await;
        if !mm_blocktemplates.contains_key(&aux_hash) {
            return JsonError::new(InvalidParams, Some("unknown aux_hash".to_string()), id).into()
        }

        // Validate blob
        let Some(blob) = params.get("blob") else {
            return JsonError::new(InvalidParams, Some("missing blob".to_string()), id).into()
        };
        let Some(blob) = blob.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid blob format".to_string()), id).into()
        };
        let Ok(block) = monero_block_deserialize(blob) else {
            return JsonError::new(InvalidParams, Some("invalid blob format".to_string()), id).into()
        };

        // Validate merkle_proof
        let Some(merkle_proof_j) = params.get("merkle_proof") else {
            return JsonError::new(InvalidParams, Some("missing merkle_proof".to_string()), id)
                .into()
        };
        let Some(merkle_proof_j) = merkle_proof_j.get::<Vec<JsonValue>>() else {
            return JsonError::new(
                InvalidParams,
                Some("invalid merkle_proof format".to_string()),
                id,
            )
            .into()
        };
        let mut merkle_proof: Vec<monero::Hash> = Vec::with_capacity(merkle_proof_j.len());
        for hash in merkle_proof_j.iter() {
            match hash.get::<String>() {
                Some(v) => {
                    let Ok(val) = monero::Hash::from_hex(v) else {
                        return JsonError::new(
                            InvalidParams,
                            Some("invalid merkle_proof format".to_string()),
                            id,
                        )
                        .into()
                    };

                    merkle_proof.push(val);
                }
                None => {
                    return JsonError::new(
                        InvalidParams,
                        Some("invalid merkle_proof format".to_string()),
                        id,
                    )
                    .into()
                }
            }
        }

        // Validate path
        let Some(path) = params.get("path") else {
            return JsonError::new(InvalidParams, Some("missing path".to_string()), id).into()
        };
        let Some(path) = path.get::<f64>() else {
            return JsonError::new(InvalidParams, Some("invalid path format".to_string()), id).into()
        };
        let path = *path as u32;

        // Validate seed_hash
        let Some(seed_hash) = params.get("seed_hash") else {
            return JsonError::new(InvalidParams, Some("missing seed_hash".to_string()), id).into()
        };
        let Some(seed_hash) = seed_hash.get::<String>() else {
            return JsonError::new(InvalidParams, Some("invalid seed_hash format".to_string()), id)
                .into()
        };
        let Ok(seed_hash) = monero::Hash::from_hex(seed_hash) else {
            return JsonError::new(InvalidParams, Some("invalid seed_hash format".to_string()), id)
                .into()
        };
        let Ok(seed_hash) = FixedByteArray::from_bytes(seed_hash.as_bytes()) else {
            return JsonError::new(InvalidParams, Some("invalid seed_hash format".to_string()), id)
                .into()
        };

        info!(
            target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
            "[RPC-XMR] Got solution submission: aux_hash={aux_hash}",
        );

        // =======================================
        // Now we will validate the block contents
        // =======================================

        let Ok(merkle_root) = extract_aux_merkle_root_from_block(&block) else {
            error!(
                target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                "[RPC-XMR] Extracting aux_merkle_root from XMR block failed",
            );
            return JsonError::new(InvalidParams, None, id).into()
        };

        let Some(merkle_root) = merkle_root else {
            error!(
                target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                "[RPC-XMR] Did not find merge mining hash in block",
            );
            return JsonError::new(InvalidParams, None, id).into()
        };

        // Verify the merge mining hash
        let Some(aux_hash_merkle_proof) = MerkleProof::try_construct(merkle_proof, path) else {
            return JsonError::new(
                InvalidParams,
                Some("invalid aux_hash merkle proof".to_string()),
                id,
            )
            .into()
        };

        if aux_hash_merkle_proof.calculate_root(&monero::Hash::from(aux_hash.inner())) !=
            merkle_root
        {
            error!(
                target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                "[RPC-XMR] Could not validate aux_hash Merkle root",
            );
            return JsonError::new(
                InvalidParams,
                Some("invalid aux_hash merkle proof".to_string()),
                id,
            )
            .into()
        }

        // Construct MoneroPowData
        let aux_chain_hashes =
            MaxSizeVec::from_items_truncate(vec![monero::Hash::from(aux_hash.inner())]);
        let monero_pow_data =
            match MoneroPowData::new(block, seed_hash, aux_chain_hashes, *aux_hash.inner()) {
                Ok(v) => v,
                Err(e) => {
                    error!(
                        target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                        "[RPC-XMR] Failed constructing MoneroPowData: {e}",
                    );
                    return JsonError::new(
                        InvalidParams,
                        Some("failed constructing moneropowdata".to_string()),
                        id,
                    )
                    .into()
                }
            };

        if !monero_pow_data.is_coinbase_valid_merkle_root() {
            error!(
                target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                "[RPC-XMR] MoneroPowData invalid coinbase Merkle proof",
            );
            return JsonError::new(
                InvalidParams,
                Some("invalid coinbase merkle proof".to_string()),
                id,
            )
            .into()
        }

        // Append MoneroPowData to the DarkFi block and verify it.
        let extended_fork = match self.best_current_fork().await {
            Ok(f) => f,
            Err(e) => {
                error!(
                    target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                    "[RPC-XMR] Finding best fork index failed: {e}",
                );
                return JsonError::new(ErrorCode::InternalError, None, id).into()
            }
        };

        let (block, secret) = &mm_blocktemplates.get(&aux_hash).unwrap();
        let mut block = block.clone();
        block.header.pow_data = PowData::Monero(monero_pow_data);
        block.sign(secret);

        if let Err(e) = extended_fork.module.verify_current_block(&block.header) {
            error!(
                target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
                "[RPC-XMR] Failed verifying merge mined block: {e}",
            );
            return JsonError::new(ErrorCode::InternalError, None, id).into()
        }

        info!(
            target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
            "[RPC-XMR] Success verifying merge mined block!",
        );

        // At this point we should be able to clear the working job.
        // We still won't release the lock in hope of proposing the block
        // first.
        mm_blocktemplates.clear();

        // Propose the new block.
        info!(
            target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
            "[RPC-XMR] Proposing new block to network",
        );
        let proposal = Proposal::new(block);
        if let Err(e) = self.validator.append_proposal(&proposal).await {
            error!(
                target: "darkfid::rpc_xmr::xmr_merge_submit_solution",
                "[RPC-XMR] Error proposing new block: {e}",
            );
            return JsonError::new(ErrorCode::InternalError, None, id).into()
        }

        info!(
            target: "darkfid::rpc_xmr::xmr_merge_mining_submit_solution",
            "[RPC-XMR] Broadcasting new block to network",
        );
        let message = ProposalMessage(proposal);
        self.p2p_handler.p2p.broadcast(&message).await;

        JsonResponse::new(
            JsonValue::from(HashMap::from([(
                "status".to_string(),
                JsonValue::from("accepted".to_string()),
            )])),
            id,
        )
        .into()
    }
}