Implement Campaign Creation

[jdnichollsc]

Create Campaign Logic.

Definition of Done:

• A campaign account can be created by a musical artist (creator).
• The campaign includes title, description, funding goal, start/end dates, and status.
• The campaign uses a Program Derived Address (PDA) for unique identification.

Tasks:

• Define the Campaign struct.
• Create an instruction to initialize a new campaign account.
• Use validation for inputs (e.g., end_date > start_date, valid funding goal).
• Write unit tests to verify campaign creation.

Code Example:

#[account]
pub struct Campaign {
    pub creator: Pubkey,              // Creator's wallet address
    pub title: String,                // Campaign title
    pub description: String,          // Campaign description
    pub goal_amount: u64,             // Funding goal in lamports
    pub current_amount: u64,          // Current amount pledged
    pub start_date: i64,              // Campaign start time
    pub end_date: i64,                // Campaign end time
    pub status: u8,                   // 0 = active, 1 = completed, 2 = cancelled
}

#[derive(Accounts)]
pub struct CreateCampaign<'info> {
    #[account(init, payer = creator, space = 8 + Campaign::MAX_SIZE, seeds = [b"campaign", creator.key().as_ref()], bump)]
    pub campaign: Account<'info, Campaign>,
    #[account(mut)]
    pub creator: Signer<'info>,
    pub system_program: Program<'info, System>,
}

pub fn create_campaign(
    ctx: Context<CreateCampaign>,
    title: String,
    description: String,
    goal_amount: u64,
    start_date: i64,
    end_date: i64,
) -> Result<()> {
    require!(end_date > start_date, ErrorCode::InvalidDates);
    require!(goal_amount > 0, ErrorCode::InvalidGoalAmount);

    let campaign = &mut ctx.accounts.campaign;
    campaign.creator = *ctx.accounts.creator.key;
    campaign.title = title;
    campaign.description = description;
    campaign.goal_amount = goal_amount;
    campaign.current_amount = 0;
    campaign.start_date = start_date;
    campaign.end_date = end_date;
    campaign.status = 0; // Active
    Ok(())
}