puzzle mode (not completed)

src/main.rs

@@ -32,6 +32,10 @@ struct Args {
     /// Display grid when solving
     #[arg(long)]
     grid: bool,
+
+	/// Create puzzle
+    #[arg(long)]
+    puzzle: bool,
 }
 
 
@@ -53,10 +57,17 @@ fn main() {
     	solver.benchmark(number);
     	return
     }
-    if let Err(reason) = solver.solve(args.limit) {
+
+    let result = if args.puzzle {
+        solver.make_puzzle().map(|_| ())
+    } else {
+        solver.solve(args.limit).map(|_| ())
+    };
+    
+    if let Err(reason) = result {
         println!("{}", reason);
         if args.debug {
-        	solver.display(solver::ui::DisplayMode::Full);
+            solver.display(solver::ui::DisplayMode::Full);
         }
     }
 }

src/solver/cell.rs

@@ -64,6 +64,10 @@ impl Cell {
 	        .collect()
 	}
 
+	pub fn get_state(&self) -> Option<usize> {
+		self.state
+	}
+
 	pub fn get_existing(&self) -> Vec<usize> {
 		if let Some(state) = self.state {
 	        vec![state]

src/solver/mod.rs

@@ -3,6 +3,7 @@ use std::time::Instant;
 use std::time::Duration;
 use std::ops::MulAssign;
 use std::fmt;
+use rand::Rng;
 
 pub mod sudoku;
 pub mod ui;
@@ -115,6 +116,7 @@ pub struct Solver {
 	debug_display: bool,
 	grid_display: bool,
 	solve_display: bool,
+	solve_progress_display: bool,
 	collapse_option: cell::CollapseOption,
 }
 
@@ -132,10 +134,42 @@ impl Solver {
 			debug_display: false,
 			grid_display: false,
 			solve_display: true,
+			solve_progress_display: true,
 			collapse_option: cell::CollapseOption::Random,
 		}
 	}
 
+    pub fn make_puzzle(&mut self) -> Result<(), WaveError> {
+    	self.solve_display = false;
+    	println!("# generating full...");
+    	let _ = self.solve(None)?;
+
+    	println!("\n\n# erasing cells...");
+    	let mut rng = rand::thread_rng();
+    	
+    	let erase_cell = loop {
+    	    let pos = (rng.gen_range(1..=self.size), rng.gen_range(1..=self.size));
+    	    if let Some(state) = self.grid[pos.0][pos.1].get_state() {
+    	        self.grid[pos.0][pos.1].reset_state();
+    	        break (pos, state);
+    	    }
+    	};
+
+    	let blocking_cell = cell::BlockingCell {
+    	    state: erase_cell.1,
+    	    position: erase_cell.0,
+    	};
+    	
+       	self.propagate_backtrack(erase_cell.0, blocking_cell); // get min allowed state number
+		// while min state number < 2 => loop
+
+       	
+		println!();
+    	self.display(ui::DisplayMode::Full);
+    	self.solve_display = true;
+		Ok(())
+    }
+
 	fn reset_grid(&mut self) {
 		let states = (1..=self.size).collect();
 		let empty_grid = vec![vec![cell::Cell::new(states); self.size]; self.size];
@@ -154,6 +188,7 @@ impl Solver {
 
 	pub fn benchmark(&mut self, solve_number: usize) {
 		self.solve_display = false;
+		self.solve_progress_display = false;
 		println!();
 		if self.grid_display {
 			self.display(ui::DisplayMode::Full);
@@ -179,7 +214,6 @@ impl Solver {
 			if !self.debug_display && !self.grid_display {
 				let progress = (index + 1) as f32 / solve_number as f32;
 				self.progress_bar(progress);
-				//print!("\r- {} ({}/{})", progress, index + 1, solve_number);
 			}
 			if self.grid_display {
 				if !self.debug_display {
@@ -198,6 +232,7 @@ impl Solver {
 		println!("\nbenchmark {} (n = {})\n{}\n({} errors)", self.square_size, solve_number, results_sum, error_number);
 
 		self.solve_display = true;
+		self.solve_progress_display = true;
 	}
 
 	pub fn solve(&mut self, solver_limit: Option<usize>) -> Result<SolveResult, WaveError> {
@@ -251,7 +286,7 @@ impl Solver {
 			collapse_counter.0 += 1;
 			collapse_counter.1 += collapse_start.elapsed();
 			
-			if !self.debug_display && !self.grid_display && self.solve_display {
+			if !self.debug_display && !self.grid_display && self.solve_progress_display {
 				self.progress_bar(self.history.len() as f32/((self.size*self.size) as f32));
 		    }
 		    if let Some(limit) = solver_limit {
@@ -322,7 +357,7 @@ impl Solver {
 		}
 	}
 
-	fn backtrack(&mut self) -> Result<(), WaveError> {
+	fn get_last_fork(&mut self) -> Result<Step, WaveError> {
 		let mut fork: Option<Step> = None;
         while let Some(step) = self.history.pop() {
         	if self.last_move_index == 0 {
@@ -343,12 +378,20 @@ impl Solver {
         	}
 			self.debug(&format!("* backtracking [{}][{}] : {}", step.position.0, step.position.1, step.state_set));
         }
+        match fork {
+        	Some(step) => {
+        		self.debug(&format!("* fork [{}][{}] : {}", step.position.0, step.position.1, step.state_set));
+        		Ok(step)
+        	},
+        	None => {
+	        	self.debug("x backtracked to start");
+        		Err(WaveError::NoHistory)
+        	}
+        }
+	}
 
-        let Some(step) = fork else {
-        	self.debug("x backtracked to start");
-        	return Err(WaveError::NoHistory)
-        };
-        self.debug(&format!("* fork [{}][{}] : {}", step.position.0, step.position.1, step.state_set));
+	fn backtrack(&mut self) -> Result<(), WaveError> {
+		let step = self.get_last_fork()?;
 
        	let mut state_selected_set = HashSet::new();
        	state_selected_set.insert(step.state_set);