Updated space calculation

- Implemented Space trait for dynamic structures

- Added constants files

- Added require macros for string length and rating range

- Added error enum

programs/anchor-movie-review-program/src/constants.rs

@@ -0,0 +1,8 @@
+pub const ANCHOR_DISCRIMINATOR: usize = 8;
+pub const PUBKEY_SIZE: usize = 32;
+pub const U8_SIZE: usize = 1;
+pub const STRING_LENGTH_PREFIX: usize = 4;
+pub const MAX_DESCRIPTION_LENGTH: usize = 50;
+pub const MAX_TITLE_LENGTH: usize = 20;
+pub const MAX_RATING: u8 = 5;
+pub const MIN_RATING: u8 = 1;

programs/anchor-movie-review-program/src/lib.rs

@@ -1,12 +1,25 @@
 use anchor_lang::prelude::*;
 
+pub mod constants;
+
+pub use constants::*;
+
 declare_id!("FmzAVsBmJWcfkfe7VrvEi7pLA9ALLDWB3NoU2MvLrCZj");
 
 #[program]
 pub mod anchor_movie_review_program {
     use super::*;
 
     pub fn add_movie_review(ctx: Context<AddMovieReview>, title: String, description: String, rating: u8) -> Result<()> {
+        // We require that the rating is between 1 and 5
+        require!(rating >= MIN_RATING && rating <= MAX_RATING, MovieReviewError::InvalidRating);
+
+        // We require that the title is not longer than 20 characters
+        require!(title.len() <= MAX_TITLE_LENGTH, MovieReviewError::TitleTooLong);
+
+        // We require that the description is not longer than 50 characters
+        require!(description.len() <= MAX_DESCRIPTION_LENGTH, MovieReviewError::DescriptionTooLong);
+
         msg!("Movie review account created");
         msg!("Title: {}", title);
         msg!("Description: {}", description);
@@ -22,6 +35,12 @@ pub mod anchor_movie_review_program {
     }
 
     pub fn update_movie_review(ctx: Context<UpdateMovieReview>, title: String, description: String, rating: u8) -> Result<()> {
+        // We require that the rating is between 1 and 5
+        require!(rating >= MIN_RATING && rating <= MAX_RATING, MovieReviewError::InvalidRating);
+
+        // We require that the description is not longer than 50 characters
+        require!(description.len() <= MAX_DESCRIPTION_LENGTH, MovieReviewError::DescriptionTooLong);
+
         msg!("Movie review account space reallocated");
         msg!("Title: {}", title);
         msg!("Description: {}", description);
@@ -48,7 +67,7 @@ pub struct AddMovieReview<'info> {
         seeds=[title.as_bytes(), initializer.key().as_ref()], 
         bump, 
         payer = initializer, 
-        space = 8 + 32 + 1 + 4 + title.len() + 4 + description.len()
+        space = MovieAccountState::INIT_SPACE + title.len() + description.len() // We add the length of the title and description to the init space
     )]
     pub movie_review: Account<'info, MovieAccountState>,
     #[account(mut)]
@@ -63,7 +82,7 @@ pub struct UpdateMovieReview<'info> {
         mut,
         seeds=[title.as_bytes(), initializer.key().as_ref()],
         bump,
-        realloc = 8 + 32 + 1 + 4 + title.len() + 4 + description.len(),
+        realloc = MovieAccountState::INIT_SPACE + title.len() + description.len(), // We add the length of the title and description to the init space
         realloc::payer = initializer,
         realloc::zero = true
     )]
@@ -95,3 +114,22 @@ pub struct MovieAccountState {
     pub title: String,
     pub description: String,
 }
+
+/*
+    For the MovieAccountState account, since it is dynamic, we implement the Space trait to calculate the space required for the account.
+    We add the STRING_LENGTH_PREFIX twice to the space to account for the title and description string prefix.
+    We need to add the length of the title and description to the space upon initialization.
+ */
+impl Space for MovieAccountState {
+    const INIT_SPACE: usize = ANCHOR_DISCRIMINATOR + PUBKEY_SIZE + U8_SIZE + STRING_LENGTH_PREFIX + STRING_LENGTH_PREFIX;
+}
+
+#[error_code]
+enum MovieReviewError {
+    #[msg("Rating must be between 1 and 5")]
+    InvalidRating,
+    #[msg("Movie Title too long")]
+    TitleTooLong,
+    #[msg("Movie Description too long")]
+    DescriptionTooLong,
+}