/**
 * Chain Configuration Utilities
 *
 * Provides helper functions to customize chain configurations (e.g., RPC URLs)
 * without needing to recreate entire ChainWalletConfig objects.
 *
 * @module chain-config
 */

import { ChainWalletConfig } from "./types";
import { DefaultChains } from "./constant";

/**
 * Override configuration for a single chain
 */
export interface ChainOverride {
    chainId: number;
    overrides: Partial<ChainWalletConfig>;
}

/**
 * Get a single chain configuration with optional overrides.
 *
 * @param chainId - The chain ID to retrieve
 * @param overrides - Partial configuration to override (e.g., rpcUrl, bundlerUrl)
 * @returns Complete chain configuration with overrides applied
 * @throws Error if chainId is not found in DefaultChains
 *
 * @example
 * ```typescript
 * // Override RPC URL with your own Alchemy key
 * const ethConfig = getChainConfig(1, {
 *     rpcUrl: "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY"
 * });
 *
 * const wallet = new EVMChainWallet(ethConfig, privateKey, 0);
 * ```
 *
 * @example
 * ```typescript
 * // Override multiple properties
 * const baseConfig = getChainConfig(8453, {
 *     rpcUrl: "https://base-mainnet.g.alchemy.com/v2/YOUR_KEY",
 *     aaSupport: {
 *         enabled: true,
 *         bundlerUrl: "https://your-bundler.com",
 *         paymasterUrl: "https://your-paymaster.com",
 *         // ... other AA config
 *     }
 * });
 * ```
 */
export function getChainConfig(
    chainId: number,
    overrides?: Partial<ChainWalletConfig>
): ChainWalletConfig {
    const baseConfig = DefaultChains.find(c => c.chainId === chainId);

    if (!baseConfig) {
        throw new Error(
            `Chain with ID ${chainId} not found in DefaultChains. ` +
            `Available chains: ${DefaultChains.map(c => `${c.name} (${c.chainId})`).join(', ')}`
        );
    }

    if (!overrides) {
        return { ...baseConfig };
    }

    return { ...baseConfig, ...overrides };
}

/**
 * Get multiple chain configurations with overrides applied.
 *
 * @param overrides - Array of chain overrides
 * @returns Array of complete chain configurations
 * @throws Error if any chainId is not found
 *
 * @example
 * ```typescript
 * // Configure multiple chains with custom RPC URLs
 * const chains = getMultipleChainConfigs([
 *     {
 *         chainId: 1,
 *         overrides: { rpcUrl: "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY" }
 *     },
 *     {
 *         chainId: 56,
 *         overrides: { rpcUrl: "https://bsc-dataseed.binance.org/" }
 *     },
 *     {
 *         chainId: 8453,
 *         overrides: { rpcUrl: "https://base-mainnet.g.alchemy.com/v2/YOUR_KEY" }
 *     }
 * ]);
 *
 * // Use the configured chains
 * const [ethConfig, bscConfig, baseConfig] = chains;
 * ```
 */
export function getMultipleChainConfigs(
    overrides: ChainOverride[]
): ChainWalletConfig[] {
    return overrides.map(({ chainId, overrides: configOverrides }) =>
        getChainConfig(chainId, configOverrides)
    );
}

/**
 * Get all default chains with optional global overrides.
 * Useful when you want to apply the same override to all chains.
 *
 * @param globalOverrides - Overrides to apply to all chains
 * @returns Array of all chain configurations with overrides
 *
 * @example
 * ```typescript
 * // Use custom RPC provider for all chains (not recommended, just for demo)
 * const allChains = getAllChainsWithOverrides();
 * ```
 *
 * @example
 * ```typescript
 * // Get all chains without modifications
 * const defaultChains = getAllChainsWithOverrides();
 * ```
 */
export function getAllChainsWithOverrides(
    globalOverrides?: Partial<ChainWalletConfig>
): ChainWalletConfig[] {
    if (!globalOverrides) {
        return DefaultChains.map(c => ({ ...c }));
    }

    return DefaultChains.map(chain => ({ ...chain, ...globalOverrides }));
}

/**
 * Create a custom chains list with selective overrides.
 * This is the most flexible option - allows you to override some chains
 * while keeping others as default.
 *
 * @param overrides - Map of chainId to overrides
 * @returns Array of all chain configurations with selective overrides
 *
 * @example
 * ```typescript
 * // Override only specific chains, keep others as default
 * const chains = getCustomizedChains({
 *     1: { rpcUrl: "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY" },
 *     8453: { rpcUrl: "https://base-mainnet.g.alchemy.com/v2/YOUR_KEY" },
 *     // Other chains (56, 10, 42161) will use defaults
 * });
 *
 * // Use with multi-chain savings manager
 * const savingsManager = new MultiChainSavingsManager(vm, chains);
 * ```
 */
export function getCustomizedChains(
    overrides: Record<number, Partial<ChainWalletConfig>>
): ChainWalletConfig[] {
    return DefaultChains.map(chain => {
        const override = overrides[chain.chainId];
        if (!override) {
            return { ...chain };
        }
        return { ...chain, ...override };
    });
}

/**
 * Helper function to quickly override just the RPC URL for a chain.
 * Convenience wrapper around getChainConfig.
 *
 * @param chainId - The chain ID to configure
 * @param rpcUrl - The custom RPC URL
 * @returns Complete chain configuration with new RPC URL
 *
 * @example
 * ```typescript
 * const ethConfig = withCustomRpc(1, "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY");
 * const wallet = new EVMChainWallet(ethConfig, privateKey, 0);
 * ```
 */
export function withCustomRpc(chainId: number, rpcUrl: string): ChainWalletConfig {
    return getChainConfig(chainId, { rpcUrl });
}

/**
 * Helper function to quickly override multiple chains' RPC URLs.
 *
 * @param rpcOverrides - Map of chainId to RPC URL
 * @returns Array of chain configurations with custom RPC URLs
 *
 * @example
 * ```typescript
 * const chains = withCustomRpcs({
 *     1: "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY",
 *     56: "https://bsc-dataseed.binance.org/",
 *     8453: "https://base-mainnet.g.alchemy.com/v2/YOUR_KEY"
 * });
 * ```
 */
export function withCustomRpcs(
    rpcOverrides: Record<number, string>
): ChainWalletConfig[] {
    return Object.entries(rpcOverrides).map(([chainId, rpcUrl]) =>
        withCustomRpc(Number(chainId), rpcUrl)
    );
}

/**
 * Get a chain by name (case-insensitive) with optional overrides.
 *
 * @param chainName - Name of the chain (e.g., "Ethereum", "BSC", "Base")
 * @param overrides - Optional overrides to apply
 * @returns Complete chain configuration
 * @throws Error if chain name is not found
 *
 * @example
 * ```typescript
 * const ethConfig = getChainByName("Ethereum", {
 *     rpcUrl: "https://eth-mainnet.g.alchemy.com/v2/YOUR_KEY"
 * });
 *
 * const baseConfig = getChainByName("base", {
 *     rpcUrl: "https://base-mainnet.g.alchemy.com/v2/YOUR_KEY"
 * });
 * ```
 */
export function getChainByName(
    chainName: string,
    overrides?: Partial<ChainWalletConfig>
): ChainWalletConfig {
    const normalizedName = chainName.toLowerCase();
    const baseConfig = DefaultChains.find(
        c => c.name.toLowerCase() === normalizedName
    );

    if (!baseConfig) {
        throw new Error(
            `Chain "${chainName}" not found in DefaultChains. ` +
            `Available chains: ${DefaultChains.map(c => c.name).join(', ')}`
        );
    }

    if (!overrides) {
        return { ...baseConfig };
    }

    return { ...baseConfig, ...overrides };
}

/**
 * Predefined chain ID constants for convenience.
 * Use these instead of hardcoding chain IDs.
 */
export const ChainId = {
    ETHEREUM: 1,
    BSC: 56,
    BASE: 8453,
    ARBITRUM: 42161,
    OPTIMISM: 10,
    SOLANA: 123456789, // Pseudo chain ID for Solana
} as const;

/**
 * Predefined chain name constants for convenience.
 */
export const ChainName = {
    ETHEREUM: "Ethereum",
    BSC: "BSC",
    BASE: "Base",
    ARBITRUM: "Arbitrum One",
    OPTIMISM: "OP Mainnet",
    SOLANA: "Solana",
} as const;