From d83f4e04dcabf802ed7f8dac4afa05fcfe1359de Mon Sep 17 00:00:00 2001
From: lashman <lashman@robotbrush.com>
Date: Fri, 30 May 2025 21:01:07 +0300
Subject: [PATCH] solver state and module glue

---
 cruciverb-core/src/solver/mod.rs   |  5 ++
 cruciverb-core/src/solver/state.rs | 78 ++++++++++++++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 cruciverb-core/src/solver/mod.rs
 create mode 100644 cruciverb-core/src/solver/state.rs

diff --git a/cruciverb-core/src/solver/mod.rs b/cruciverb-core/src/solver/mod.rs
new file mode 100644
index 0000000..efbe65e
--- /dev/null
+++ b/cruciverb-core/src/solver/mod.rs
@@ -0,0 +1,5 @@
+pub mod candidate;
+pub mod csp;
+pub mod state;
+
+pub use csp::{SolveResult, solve};
diff --git a/cruciverb-core/src/solver/state.rs b/cruciverb-core/src/solver/state.rs
new file mode 100644
index 0000000..0bb0b47
--- /dev/null
+++ b/cruciverb-core/src/solver/state.rs
@@ -0,0 +1,78 @@
+use crate::dict::index::WordIndex;
+use crate::grid::slot::Slot;
+
+pub struct SolverState {
+    pub assignments: Vec<Option<usize>>,
+    pub used_words: Vec<bool>,
+    pub grid_letters: Vec<Vec<Option<u8>>>,
+    pub cell_domains: Vec<Vec<u32>>,
+    pub width: usize,
+    pub height: usize,
+}
+
+impl SolverState {
+    pub fn new(slots: &[Slot], width: usize, height: usize, dict_size: usize) -> Self {
+        let all_bits = (1u32 << 26) - 1;
+        Self {
+            assignments: vec![None; slots.len()],
+            used_words: vec![false; dict_size],
+            grid_letters: vec![vec![None; width]; height],
+            cell_domains: vec![vec![all_bits; width]; height],
+            width,
+            height,
+        }
+    }
+
+    pub fn init_domains(&mut self, slots: &[Slot], dict: &WordIndex) {
+        for slot in slots {
+            for (pos, &(r, c)) in slot.cells().iter().enumerate() {
+                let allowed = dict.allowed_letters(slot.length, pos);
+                if allowed != 0 {
+                    self.cell_domains[r][c] &= allowed;
+                }
+            }
+        }
+    }
+
+    pub fn get_domain(&self, r: usize, c: usize) -> u32 {
+        self.cell_domains[r][c]
+    }
+
+    pub fn set_domain(&mut self, r: usize, c: usize, domain: u32) {
+        self.cell_domains[r][c] = domain;
+    }
+
+    pub fn get_letter(&self, row: usize, col: usize) -> Option<u8> {
+        self.grid_letters[row][col]
+    }
+
+    pub fn set_letter(&mut self, row: usize, col: usize, letter: u8) {
+        self.grid_letters[row][col] = Some(letter);
+    }
+
+    pub fn clear_letter(&mut self, row: usize, col: usize) {
+        self.grid_letters[row][col] = None;
+    }
+
+    pub fn mark_used(&mut self, word_idx: usize) {
+        self.used_words[word_idx] = true;
+    }
+
+    pub fn unmark_used(&mut self, word_idx: usize) {
+        self.used_words[word_idx] = false;
+    }
+
+    pub fn is_used(&self, word_idx: usize) -> bool {
+        self.used_words[word_idx]
+    }
+
+    pub fn current_constraints(&self, slot: &Slot) -> Vec<(usize, u8)> {
+        let mut constraints = Vec::new();
+        for (pos, (r, c)) in slot.cells().iter().enumerate() {
+            if let Some(letter) = self.get_letter(*r, *c) {
+                constraints.push((pos, letter));
+            }
+        }
+        constraints
+    }
+}