formualizer-eval 0.6.0

use crate::SheetId;
use crate::engine::arena::{AstNodeData, AstNodeId, DataStore};
use crate::engine::sheet_registry::SheetRegistry;
use formualizer_common::Coord as AbsCoord;
use formualizer_common::CoordBuildHasher;
use formualizer_common::ExcelError;
use formualizer_common::PackedSheetCell;
use formualizer_parse::parser::{CollectPolicy, ReferenceType};
use std::collections::HashMap;

/// Compact range descriptor used during planning (engine-only)
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
pub enum RangeKey {
    Rect {
        sheet: SheetId,
        start: AbsCoord,
        end: AbsCoord, // inclusive
    },
    WholeRow {
        sheet: SheetId,
        row: u32,
    },
    WholeCol {
        sheet: SheetId,
        col: u32,
    },
    /// Partially bounded rectangle; None means unbounded in that direction
    OpenRect {
        sheet: SheetId,
        start: Option<AbsCoord>,
        end: Option<AbsCoord>,
    },
}

/// Bitflags conveying per-formula traits
pub type FormulaFlags = u8;
pub const F_VOLATILE: FormulaFlags = 0b0000_0001;
pub const F_HAS_RANGES: FormulaFlags = 0b0000_0010;
pub const F_HAS_NAMES: FormulaFlags = 0b0000_0100;
pub const F_HAS_TABLES: FormulaFlags = 0b0001_0000;
pub const F_LIKELY_ARRAY: FormulaFlags = 0b0000_1000;

#[derive(Debug, Default, Clone)]
pub struct DependencyPlan {
    pub formula_targets: Vec<(SheetId, AbsCoord)>,
    pub global_cells: Vec<(SheetId, AbsCoord)>,
    pub vertex_pool: Vec<(SheetId, AbsCoord)>,
    pub vertex_pool_packed: Vec<PackedSheetCell>,
    pub formula_target_pool_indices: Vec<u32>,
    pub global_cell_pool_indices: Vec<u32>,
    pub per_formula_cells: Vec<Vec<u32>>, // indices into global_cells
    pub per_formula_ranges: Vec<Vec<RangeKey>>,
    pub per_formula_names: Vec<Vec<String>>,
    pub per_formula_tables: Vec<Vec<String>>,
    pub per_formula_flags: Vec<FormulaFlags>,
    pub edges_flat: Option<Vec<u32>>, // optional flat adjacency (indices into global_cells)
    pub offsets: Option<Vec<u32>>,    // len = num_formulas + 1 when edges_flat is Some
}

#[derive(Debug, Clone, Copy)]
pub enum DependencyPlanAst<'a> {
    Tree(&'a formualizer_parse::parser::ASTNode),
    Arena(AstNodeId),
}

fn collect_references_arena(
    data_store: &DataStore,
    ast_id: AstNodeId,
    sheet_reg: &SheetRegistry,
    policy: &CollectPolicy,
) -> Result<Vec<ReferenceType>, ExcelError> {
    let mut out = Vec::new();
    let mut stack = Vec::with_capacity(8);
    stack.push(ast_id);

    while let Some(node_id) = stack.pop() {
        let Some(node) = data_store.get_node(node_id) else {
            return Err(ExcelError::new(formualizer_common::ExcelErrorKind::Value)
                .with_message("Missing interned formula AST"));
        };

        match node {
            AstNodeData::Reference { ref_type, .. } => {
                let reference = data_store.reconstruct_reference_type_for_eval(ref_type, sheet_reg);
                match reference {
                    ReferenceType::Range {
                        sheet,
                        start_row,
                        start_col,
                        end_row,
                        end_col,
                        start_row_abs,
                        start_col_abs,
                        end_row_abs,
                        end_col_abs,
                    } => {
                        if policy.expand_small_ranges
                            && let (Some(sr), Some(sc), Some(er), Some(ec)) =
                                (start_row, start_col, end_row, end_col)
                        {
                            let rows = er.saturating_sub(sr) + 1;
                            let cols = ec.saturating_sub(sc) + 1;
                            let area = rows.saturating_mul(cols);
                            if area as usize <= policy.range_expansion_limit {
                                let row_abs = start_row_abs && end_row_abs;
                                let col_abs = start_col_abs && end_col_abs;
                                for r in sr..=er {
                                    for c in sc..=ec {
                                        out.push(ReferenceType::Cell {
                                            sheet: sheet.clone(),
                                            row: r,
                                            col: c,
                                            row_abs,
                                            col_abs,
                                        });
                                    }
                                }
                                continue;
                            }
                        }
                        out.push(ReferenceType::Range {
                            sheet,
                            start_row,
                            start_col,
                            end_row,
                            end_col,
                            start_row_abs,
                            start_col_abs,
                            end_row_abs,
                            end_col_abs,
                        });
                    }
                    ReferenceType::NamedRange(_) if !policy.include_names => {}
                    other => out.push(other),
                }
            }
            AstNodeData::UnaryOp { expr_id, .. } => stack.push(*expr_id),
            AstNodeData::BinaryOp {
                left_id, right_id, ..
            } => {
                stack.push(*right_id);
                stack.push(*left_id);
            }
            AstNodeData::Function { .. } => {
                if let Some(args) = data_store.get_args(node_id) {
                    for arg in args.iter().rev() {
                        stack.push(*arg);
                    }
                }
            }
            AstNodeData::Array { .. } => {
                if let Some((_, _, elems)) = data_store.get_array_elems(node_id) {
                    for elem in elems.iter().rev() {
                        stack.push(*elem);
                    }
                }
            }
            AstNodeData::Literal(_) => {}
        }
    }

    Ok(out)
}

/// Build a compact dependency plan from ASTs without mutating the graph.
/// Sheets referenced by name are resolved/created through SheetRegistry at plan time.
pub fn build_dependency_plan<'a, I>(
    sheet_reg: &mut SheetRegistry,
    formulas: I,
    policy: &CollectPolicy,
    volatile_flags: Option<&[bool]>,
) -> Result<DependencyPlan, ExcelError>
where
    I: Iterator<Item = (&'a str, u32, u32, &'a formualizer_parse::parser::ASTNode)>,
{
    let mut plan = DependencyPlan::default();

    // Global cell pool: packed absolute cell -> index.
    //
    // Uses CoordBuildHasher because FxHasher's weak avalanche collides badly
    // on structured packed keys (PackedSheetCell reserves bits 50..64 and has
    // narrow dynamic range on row-major workloads), turning this O(N) loop
    // into O(N^2). See formualizer_common::coord_hash.
    let mut cell_index: HashMap<PackedSheetCell, u32, CoordBuildHasher> =
        HashMap::with_hasher(CoordBuildHasher);
    // Unified vertex pool for loader-specialized ensure.
    let mut vertex_pool_index: HashMap<PackedSheetCell, u32, CoordBuildHasher> =
        HashMap::with_hasher(CoordBuildHasher);

    let mut ensure_vertex_pool_index =
        |plan: &mut DependencyPlan, key: (SheetId, AbsCoord)| -> u32 {
            let packed = PackedSheetCell::try_new(key.0, key.1.row(), key.1.col())
                .expect("plan vertex pool coordinate must fit PackedSheetCell");
            match vertex_pool_index.get(&packed) {
                Some(&idx) => idx,
                None => {
                    let new_idx = plan.vertex_pool.len() as u32;
                    plan.vertex_pool.push(key);
                    plan.vertex_pool_packed.push(packed);
                    vertex_pool_index.insert(packed, new_idx);
                    new_idx
                }
            }
        };

    for (i, (sheet_name, row, col, ast)) in formulas.enumerate() {
        let sheet_id = sheet_reg.id_for(sheet_name);
        let target = (sheet_id, AbsCoord::from_excel(row, col));
        plan.formula_targets.push(target);
        let target_pool_idx = ensure_vertex_pool_index(&mut plan, target);
        plan.formula_target_pool_indices.push(target_pool_idx);

        let mut flags: FormulaFlags = 0;
        if let Some(v) = volatile_flags.and_then(|v| v.get(i)).copied()
            && v
        {
            flags |= F_VOLATILE;
        }

        let mut per_cells: Vec<u32> = Vec::new();
        let mut per_ranges: Vec<RangeKey> = Vec::new();
        let mut per_names: Vec<String> = Vec::new();
        let mut per_tables: Vec<String> = Vec::new();

        // Collect references using core collector (may expand small ranges per policy)
        let refs = ast.collect_references(policy);
        for r in refs {
            match r {
                ReferenceType::Cell {
                    sheet, row, col, ..
                } => {
                    let dep_sheet = sheet
                        .as_deref()
                        .map(|name| sheet_reg.id_for(name))
                        .unwrap_or(sheet_id);
                    let key = (dep_sheet, AbsCoord::from_excel(row, col));
                    let packed = PackedSheetCell::try_new(dep_sheet, key.1.row(), key.1.col())
                        .expect("plan dependency coordinate must fit PackedSheetCell");
                    let idx = match cell_index.get(&packed) {
                        Some(&idx) => idx,
                        None => {
                            let new_idx = plan.global_cells.len() as u32;
                            plan.global_cells.push(key);
                            cell_index.insert(packed, new_idx);
                            let pool_idx = ensure_vertex_pool_index(&mut plan, key);
                            plan.global_cell_pool_indices.push(pool_idx);
                            new_idx
                        }
                    };
                    per_cells.push(idx);
                }
                ReferenceType::Range {
                    sheet,
                    start_row,
                    start_col,
                    end_row,
                    end_col,
                    ..
                } => {
                    let dep_sheet = sheet
                        .as_deref()
                        .map(|name| sheet_reg.id_for(name))
                        .unwrap_or(sheet_id);
                    match (start_row, start_col, end_row, end_col) {
                        (Some(sr), Some(sc), Some(er), Some(ec)) => {
                            per_ranges.push(RangeKey::Rect {
                                sheet: dep_sheet,
                                start: AbsCoord::from_excel(sr, sc),
                                end: AbsCoord::from_excel(er, ec),
                            })
                        }
                        (None, Some(c), None, Some(ec)) if c == ec => {
                            per_ranges.push(RangeKey::WholeCol {
                                sheet: dep_sheet,
                                col: c,
                            })
                        }
                        (Some(r), None, Some(er), None) if r == er => {
                            per_ranges.push(RangeKey::WholeRow {
                                sheet: dep_sheet,
                                row: r,
                            })
                        }
                        _ => per_ranges.push(RangeKey::OpenRect {
                            sheet: dep_sheet,
                            start: start_row
                                .zip(start_col)
                                .map(|(r, c)| AbsCoord::from_excel(r, c)),
                            end: end_row
                                .zip(end_col)
                                .map(|(r, c)| AbsCoord::from_excel(r, c)),
                        }),
                    }
                }
                ReferenceType::External(ext) => match ext.kind {
                    formualizer_parse::parser::ExternalRefKind::Cell { .. } => {
                        flags |= F_HAS_NAMES;
                        per_names.push(ext.raw.clone());
                    }
                    formualizer_parse::parser::ExternalRefKind::Range { .. } => {
                        flags |= F_HAS_TABLES;
                        per_tables.push(ext.raw.clone());
                    }
                },
                ReferenceType::NamedRange(name) => {
                    // Resolution handled later; mark via flags if caller cares
                    flags |= F_HAS_NAMES;
                    per_names.push(name);
                }
                ReferenceType::Table(tref) => {
                    flags |= F_HAS_TABLES;
                    per_tables.push(tref.name);
                }
                // 3D refs are parsed but not yet planned. They neither create
                // dependencies nor participate in the cell/range plan; the
                // evaluator will surface #N/IMPL! when one is encountered.
                ReferenceType::Cell3D { .. } | ReferenceType::Range3D { .. } => {}
            }
        }

        plan.per_formula_cells.push(per_cells);
        plan.per_formula_ranges.push(per_ranges);
        plan.per_formula_names.push(per_names);
        plan.per_formula_tables.push(per_tables);
        plan.per_formula_flags.push(flags);
    }

    Ok(plan)
}

/// Build a compact dependency plan from a mix of tree and arena ASTs.
pub fn build_dependency_plan_mixed<'a, I>(
    sheet_reg: &mut SheetRegistry,
    data_store: &DataStore,
    formulas: I,
    policy: &CollectPolicy,
    volatile_flags: Option<&[bool]>,
) -> Result<DependencyPlan, ExcelError>
where
    I: Iterator<Item = (&'a str, u32, u32, DependencyPlanAst<'a>)>,
{
    let mut plan = DependencyPlan::default();

    let mut cell_index: HashMap<PackedSheetCell, u32, CoordBuildHasher> =
        HashMap::with_hasher(CoordBuildHasher);
    let mut vertex_pool_index: HashMap<PackedSheetCell, u32, CoordBuildHasher> =
        HashMap::with_hasher(CoordBuildHasher);

    let mut ensure_vertex_pool_index =
        |plan: &mut DependencyPlan, key: (SheetId, AbsCoord)| -> u32 {
            let packed = PackedSheetCell::try_new(key.0, key.1.row(), key.1.col())
                .expect("plan vertex pool coordinate must fit PackedSheetCell");
            match vertex_pool_index.get(&packed) {
                Some(&idx) => idx,
                None => {
                    let new_idx = plan.vertex_pool.len() as u32;
                    plan.vertex_pool.push(key);
                    plan.vertex_pool_packed.push(packed);
                    vertex_pool_index.insert(packed, new_idx);
                    new_idx
                }
            }
        };

    for (i, (sheet_name, row, col, ast)) in formulas.enumerate() {
        let sheet_id = sheet_reg.id_for(sheet_name);
        let target = (sheet_id, AbsCoord::from_excel(row, col));
        plan.formula_targets.push(target);
        let target_pool_idx = ensure_vertex_pool_index(&mut plan, target);
        plan.formula_target_pool_indices.push(target_pool_idx);

        let mut flags: FormulaFlags = 0;
        if let Some(v) = volatile_flags.and_then(|v| v.get(i)).copied()
            && v
        {
            flags |= F_VOLATILE;
        }

        let mut per_cells: Vec<u32> = Vec::new();
        let mut per_ranges: Vec<RangeKey> = Vec::new();
        let mut per_names: Vec<String> = Vec::new();
        let mut per_tables: Vec<String> = Vec::new();

        let refs = match ast {
            DependencyPlanAst::Tree(ast) => ast.collect_references(policy).into_iter().collect(),
            DependencyPlanAst::Arena(ast_id) => {
                collect_references_arena(data_store, ast_id, sheet_reg, policy)?
            }
        };
        for r in refs {
            match r {
                ReferenceType::Cell {
                    sheet, row, col, ..
                } => {
                    let dep_sheet = sheet
                        .as_deref()
                        .map(|name| sheet_reg.id_for(name))
                        .unwrap_or(sheet_id);
                    let key = (dep_sheet, AbsCoord::from_excel(row, col));
                    let packed = PackedSheetCell::try_new(dep_sheet, key.1.row(), key.1.col())
                        .expect("plan dependency coordinate must fit PackedSheetCell");
                    let idx = match cell_index.get(&packed) {
                        Some(&idx) => idx,
                        None => {
                            let new_idx = plan.global_cells.len() as u32;
                            plan.global_cells.push(key);
                            cell_index.insert(packed, new_idx);
                            let pool_idx = ensure_vertex_pool_index(&mut plan, key);
                            plan.global_cell_pool_indices.push(pool_idx);
                            new_idx
                        }
                    };
                    per_cells.push(idx);
                }
                ReferenceType::Range {
                    sheet,
                    start_row,
                    start_col,
                    end_row,
                    end_col,
                    ..
                } => {
                    let dep_sheet = sheet
                        .as_deref()
                        .map(|name| sheet_reg.id_for(name))
                        .unwrap_or(sheet_id);
                    match (start_row, start_col, end_row, end_col) {
                        (Some(sr), Some(sc), Some(er), Some(ec)) => {
                            per_ranges.push(RangeKey::Rect {
                                sheet: dep_sheet,
                                start: AbsCoord::from_excel(sr, sc),
                                end: AbsCoord::from_excel(er, ec),
                            })
                        }
                        (None, Some(c), None, Some(ec)) if c == ec => {
                            per_ranges.push(RangeKey::WholeCol {
                                sheet: dep_sheet,
                                col: c,
                            })
                        }
                        (Some(r), None, Some(er), None) if r == er => {
                            per_ranges.push(RangeKey::WholeRow {
                                sheet: dep_sheet,
                                row: r,
                            })
                        }
                        _ => per_ranges.push(RangeKey::OpenRect {
                            sheet: dep_sheet,
                            start: start_row
                                .zip(start_col)
                                .map(|(r, c)| AbsCoord::from_excel(r, c)),
                            end: end_row
                                .zip(end_col)
                                .map(|(r, c)| AbsCoord::from_excel(r, c)),
                        }),
                    }
                }
                ReferenceType::External(ext) => match ext.kind {
                    formualizer_parse::parser::ExternalRefKind::Cell { .. } => {
                        flags |= F_HAS_NAMES;
                        per_names.push(ext.raw.clone());
                    }
                    formualizer_parse::parser::ExternalRefKind::Range { .. } => {
                        flags |= F_HAS_TABLES;
                        per_tables.push(ext.raw.clone());
                    }
                },
                ReferenceType::NamedRange(name) => {
                    flags |= F_HAS_NAMES;
                    per_names.push(name);
                }
                ReferenceType::Table(tref) => {
                    flags |= F_HAS_TABLES;
                    per_tables.push(tref.name);
                }
                ReferenceType::Cell3D { .. } | ReferenceType::Range3D { .. } => {}
            }
        }

        plan.per_formula_cells.push(per_cells);
        plan.per_formula_ranges.push(per_ranges);
        plan.per_formula_names.push(per_names);
        plan.per_formula_tables.push(per_tables);
        plan.per_formula_flags.push(flags);
    }

    Ok(plan)
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::engine::arena::DataStore;
    use crate::engine::sheet_registry::SheetRegistry;
    use formualizer_parse::parse;

    #[test]
    fn mixed_arena_plan_matches_tree_plan_for_basic_refs() {
        let asts = [
            parse("=A1+SUM(B2:C3)+NamedThing").unwrap(),
            parse("=Sheet2!D4+Table1[#Data]").unwrap(),
        ];
        let policy = CollectPolicy {
            expand_small_ranges: true,
            range_expansion_limit: 16,
            include_names: true,
        };

        let mut tree_reg = SheetRegistry::new();
        let tree_plan = build_dependency_plan(
            &mut tree_reg,
            asts.iter()
                .enumerate()
                .map(|(i, ast)| ("Sheet1", (i + 1) as u32, 5, ast)),
            &policy,
            Some(&[false, true]),
        )
        .unwrap();

        let mut arena_reg = SheetRegistry::new();
        arena_reg.id_for("Sheet1");
        let mut store = DataStore::new();
        let ids: Vec<_> = asts
            .iter()
            .map(|ast| store.store_ast(ast, &arena_reg))
            .collect();
        let arena_plan = build_dependency_plan_mixed(
            &mut arena_reg,
            &store,
            ids.iter()
                .enumerate()
                .map(|(i, id)| ("Sheet1", (i + 1) as u32, 5, DependencyPlanAst::Arena(*id))),
            &policy,
            Some(&[false, true]),
        )
        .unwrap();

        assert_eq!(arena_plan.formula_targets, tree_plan.formula_targets);
        assert_eq!(arena_plan.global_cells, tree_plan.global_cells);
        assert_eq!(arena_plan.vertex_pool, tree_plan.vertex_pool);
        assert_eq!(
            arena_plan.formula_target_pool_indices,
            tree_plan.formula_target_pool_indices
        );
        assert_eq!(
            arena_plan.global_cell_pool_indices,
            tree_plan.global_cell_pool_indices
        );
        assert_eq!(arena_plan.per_formula_cells, tree_plan.per_formula_cells);
        assert_eq!(arena_plan.per_formula_ranges, tree_plan.per_formula_ranges);
        assert_eq!(arena_plan.per_formula_names, tree_plan.per_formula_names);
        assert_eq!(arena_plan.per_formula_tables, tree_plan.per_formula_tables);
        assert_eq!(arena_plan.per_formula_flags, tree_plan.per_formula_flags);
    }
}