#![allow(unexpected_cfgs)]
#![allow(clippy::diverging_sub_expression)]

use anchor_lang::prelude::*;
use anchor_lang::system_program::{transfer, Transfer};

declare_id!("EpB6hUZUf1vvvTVAYvEN57pjUWfYswaAuKGGQDHP5iH");

#[program]
pub mod cardcli_fee_vault {
    use super::*;

    pub fn initialize(
        ctx: Context<Initialize>,
        fee_bps: u16,
        fixed_fee_usd_cents: u16,
    ) -> Result<()> {
        require!(fee_bps <= 10_000, FeeVaultError::InvalidFeeBasisPoints);
        let vault = &mut ctx.accounts.fee_vault;
        vault.authority = ctx.accounts.authority.key();
        vault.fee_bps = fee_bps;
        vault.fixed_fee_usd_cents = fixed_fee_usd_cents;
        vault.total_lamports_collected = 0;
        vault.payment_count = 0;
        vault.bump = ctx.bumps.fee_vault;
        vault.created_at = Clock::get()?.unix_timestamp;
        Ok(())
    }

    pub fn update_pricing(
        ctx: Context<UpdatePricing>,
        fee_bps: u16,
        fixed_fee_usd_cents: u16,
    ) -> Result<()> {
        require!(fee_bps <= 10_000, FeeVaultError::InvalidFeeBasisPoints);
        let vault = &mut ctx.accounts.fee_vault;
        require_keys_eq!(
            vault.authority,
            ctx.accounts.authority.key(),
            FeeVaultError::Unauthorized
        );
        vault.fee_bps = fee_bps;
        vault.fixed_fee_usd_cents = fixed_fee_usd_cents;
        Ok(())
    }

    pub fn collect_fee(
        ctx: Context<CollectFee>,
        amount_lamports: u64,
        fee_reference: [u8; 16],
    ) -> Result<()> {
        require!(amount_lamports > 0, FeeVaultError::InvalidFeeAmount);

        let cpi_accounts = Transfer {
            from: ctx.accounts.payer.to_account_info(),
            to: ctx.accounts.fee_vault.to_account_info(),
        };
        let cpi_ctx = CpiContext::new(ctx.accounts.system_program.to_account_info(), cpi_accounts);
        transfer(cpi_ctx, amount_lamports)?;

        let vault = &mut ctx.accounts.fee_vault;
        vault.total_lamports_collected = vault
            .total_lamports_collected
            .checked_add(amount_lamports)
            .ok_or(FeeVaultError::MathOverflow)?;
        vault.payment_count = vault
            .payment_count
            .checked_add(1)
            .ok_or(FeeVaultError::MathOverflow)?;

        emit!(FeeCollected {
            payer: ctx.accounts.payer.key(),
            amount_lamports,
            fee_reference,
            payment_count: vault.payment_count,
        });

        Ok(())
    }

    pub fn withdraw(ctx: Context<Withdraw>, lamports: u64) -> Result<()> {
        let vault = &ctx.accounts.fee_vault;
        require_keys_eq!(
            vault.authority,
            ctx.accounts.authority.key(),
            FeeVaultError::Unauthorized
        );
        require!(lamports > 0, FeeVaultError::InvalidFeeAmount);

        let vault_info = ctx.accounts.fee_vault.to_account_info();
        let recipient_info = ctx.accounts.recipient.to_account_info();
        let vault_balance = vault_info.lamports();
        require!(
            vault_balance >= lamports,
            FeeVaultError::InsufficientVaultBalance
        );

        **vault_info.try_borrow_mut_lamports()? -= lamports;
        **recipient_info.try_borrow_mut_lamports()? += lamports;
        Ok(())
    }
}

#[derive(Accounts)]
pub struct Initialize<'info> {
    #[account(
        init,
        payer = authority,
        space = 8 + FeeVault::LEN,
        seeds = [b"fee_vault"],
        bump,
    )]
    pub fee_vault: Account<'info, FeeVault>,
    #[account(mut)]
    pub authority: Signer<'info>,
    pub system_program: Program<'info, System>,
}

#[derive(Accounts)]
pub struct UpdatePricing<'info> {
    #[account(mut, seeds = [b"fee_vault"], bump = fee_vault.bump)]
    pub fee_vault: Account<'info, FeeVault>,
    pub authority: Signer<'info>,
}

#[derive(Accounts)]
pub struct CollectFee<'info> {
    #[account(mut, seeds = [b"fee_vault"], bump = fee_vault.bump)]
    pub fee_vault: Account<'info, FeeVault>,
    #[account(mut)]
    pub payer: Signer<'info>,
    pub system_program: Program<'info, System>,
}

#[derive(Accounts)]
pub struct Withdraw<'info> {
    #[account(mut, seeds = [b"fee_vault"], bump = fee_vault.bump)]
    pub fee_vault: Account<'info, FeeVault>,
    pub authority: Signer<'info>,
    #[account(mut)]
    pub recipient: SystemAccount<'info>,
}

#[account]
pub struct FeeVault {
    pub authority: Pubkey,
    pub fee_bps: u16,
    pub fixed_fee_usd_cents: u16,
    pub total_lamports_collected: u64,
    pub payment_count: u64,
    pub bump: u8,
    pub created_at: i64,
}

impl FeeVault {
    pub const LEN: usize = 32 + 2 + 2 + 8 + 8 + 1 + 8;
}

#[event]
pub struct FeeCollected {
    pub payer: Pubkey,
    pub amount_lamports: u64,
    pub fee_reference: [u8; 16],
    pub payment_count: u64,
}

#[error_code]
pub enum FeeVaultError {
    #[msg("Fee basis points must be between 0 and 10_000")]
    InvalidFeeBasisPoints,
    #[msg("Fee amount must be greater than zero")]
    InvalidFeeAmount,
    #[msg("Math overflow")]
    MathOverflow,
    #[msg("Unauthorized authority")]
    Unauthorized,
    #[msg("Vault balance is insufficient")]
    InsufficientVaultBalance,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn fee_vault_length_stays_stable() {
        assert_eq!(FeeVault::LEN, 61);
    }
}