use gridcraft_core::{CellError, CellRef, Value};
use gridcraft_model::{Cell, Formula, Workbook};

use crate::Calc;

fn c(s: &str) -> CellRef {
    CellRef::parse(s).unwrap()
}

struct T {
    wb: Workbook,
    calc: Calc,
}

impl T {
    fn new() -> T {
        T { wb: Workbook::new(), calc: Calc::new() }
    }
    fn set(&mut self, at: &str, input: &str) {
        let cell = if input.starts_with('=') {
            Cell::formula(Formula::new(input))
        } else {
            Cell::value(gridcraft_core::parse::parse_input(input, self.wb.date_system).value)
        };
        self.wb.sheet_mut(0).unwrap().cells.set(c(at), cell);
        self.calc.cells_changed(&mut self.wb, &[(0, c(at))]);
    }
    fn get(&self, at: &str) -> Value {
        self.wb.sheet(0).unwrap().value(c(at))
    }
    fn num(&self, at: &str) -> f64 {
        self.get(at).as_f64().unwrap_or_else(|| panic!("{at} = {:?}", self.get(at)))
    }
}

#[test]
fn spill_range_operator() {
    let mut t = T::new();
    t.set("A1", "3");
    t.set("B1", "=SEQUENCE(A1)");
    t.set("C1", "=SUM(B1#)");
    t.set("C2", "=ROWS(B1#)");
    assert_eq!((t.num("C1"), t.num("C2")), (6.0, 3.0));
    // Growing and shrinking the spill recalculates its users.
    t.set("A1", "5");
    assert_eq!((t.num("C1"), t.num("C2")), (15.0, 5.0));
    t.set("A1", "2");
    assert_eq!((t.num("C1"), t.num("C2")), (3.0, 2.0));
    // A blocked spill, or a cell that doesn't spill, gives #REF!.
    t.set("B2", "x");
    assert_eq!(t.get("C1"), Value::Error(CellError::Ref));
    t.set("B2", "");
    assert_eq!(t.num("C1"), 3.0);
    t.set("D1", "=SUM(A1#)");
    assert_eq!(t.get("D1"), Value::Error(CellError::Ref));
    // Through a defined name.
    t.wb.names.push(gridcraft_model::DefinedName {
        name: "Seq".into(),
        scope: None,
        formula: "Sheet1!$B$1#".into(),
        comment: String::new(),
        hidden: false,
    });
    t.set("E1", "=SUM(Seq)*10");
    assert_eq!(t.num("E1"), 30.0);
    t.set("A1", "4");
    assert_eq!(t.num("E1"), 100.0);
}

#[test]
fn arithmetic_and_dependencies() {
    let mut t = T::new();
    t.set("A1", "2");
    t.set("A2", "3");
    t.set("A3", "=A1*A2+1");
    assert_eq!(t.num("A3"), 7.0);
    t.set("A1", "10");
    assert_eq!(t.num("A3"), 31.0);
    t.set("B1", "=SUM(A1:A3)");
    assert_eq!(t.num("B1"), 44.0);
    t.set("A2", "0");
    assert_eq!(t.num("A3"), 1.0);
    assert_eq!(t.num("B1"), 11.0);
}

#[test]
fn chains_out_of_order() {
    let mut t = T::new();
    t.set("A5", "=A4+1");
    t.set("A4", "=A3+1");
    t.set("A3", "=A2+1");
    t.set("A2", "=A1+1");
    t.set("A1", "1");
    assert_eq!(t.num("A5"), 5.0);
}

#[test]
fn xlookup_returns_a_reference() {
    let mut t = T::new();
    for (i, (k, v)) in [("a", 1), ("b", 2), ("c", 3), ("d", 4)].iter().enumerate() {
        t.set(&format!("A{}", i + 1), k);
        t.set(&format!("B{}", i + 1), &v.to_string());
    }
    t.set("D1", "=SUM(XLOOKUP(\"b\",A1:A4,B1:B4):XLOOKUP(\"d\",A1:A4,B1:B4))");
    assert_eq!(t.num("D1"), 9.0);
    t.set("D2", "=SUM(B1:XLOOKUP(\"c\",A1:A4,B1:B4))");
    assert_eq!(t.num("D2"), 6.0);
    t.set("D3", "=CELL(\"address\",XLOOKUP(\"c\",A1:A4,B1:B4))");
    assert_eq!(t.get("D3"), Value::from("$B$3"));
    // Not found: if_not_found, else #N/A, as before.
    t.set("D4", "=XLOOKUP(\"z\",A1:A4,B1:B4,\"none\")");
    assert_eq!(t.get("D4"), Value::from("none"));
    t.set("D5", "=XLOOKUP(\"z\",A1:A4,B1:B4)");
    assert_eq!(t.get("D5"), Value::Error(CellError::NA));
    // A match on an empty cell is a blank reference: ISBLANK is TRUE and & adds nothing (#374).
    t.set("A5", "e");
    t.set("D6", "=ISBLANK(XLOOKUP(\"e\",A1:A5,B1:B5))");
    assert_eq!(t.get("D6"), Value::Bool(true));
    t.set("D7", "=\"x\"&XLOOKUP(\"e\",A1:A5,B1:B5)&\"y\"");
    assert_eq!(t.get("D7"), Value::from("xy"));
    // An empty match_mode keeps the search_mode after it: search last to first.
    t.set("A6", "b");
    t.set("B6", "20");
    t.set("D8", "=XLOOKUP(\"b\",A1:A6,B1:B6,,,-1)");
    assert_eq!(t.num("D8"), 20.0);
    t.set("D9", "=XLOOKUP(\"b\",A1:A6,B1:B6)");
    assert_eq!(t.num("D9"), 2.0);
}

#[test]
fn long_chain() {
    let mut t = T::new();
    t.set("A1", "1");
    for r in 2..=3000 {
        t.set(&format!("A{r}"), &format!("=A{}+1", r - 1));
    }
    assert_eq!(t.num("A3000"), 3000.0);
    t.set("A1", "10");
    assert_eq!(t.num("A3000"), 3009.0);
}

#[test]
fn index_with_arrays_of_positions() {
    let mut t = T::new();
    for (i, row) in [[1, 2, 3], [4, 5, 6], [7, 8, 9]].iter().enumerate() {
        for (j, v) in row.iter().enumerate() {
            t.set(&format!("{}{}", ["A", "B", "C"][j], i + 1), &v.to_string());
        }
    }
    t.set("E1", "=INDEX(A1:C3,{1;3},{1,3})");
    assert_eq!([t.num("E1"), t.num("F1"), t.num("E2"), t.num("F2")], [1.0, 3.0, 7.0, 9.0]);
    t.set("E4", "=SUM(INDEX(A1:C3,{1,2,3},2))");
    assert_eq!(t.num("E4"), 15.0);
    t.set("E5", "=INDEX({10,20,30},{3,1})");
    assert_eq!([t.num("E5"), t.num("F5")], [30.0, 10.0]);
    t.set("E7", "=INDEX(A1:C3,2,3)");
    assert_eq!(t.num("E7"), 6.0);
}

#[test]
fn errors_and_cycles() {
    let mut t = T::new();
    t.set("A1", "=1/0");
    assert_eq!(t.get("A1"), Value::Error(CellError::Div0));
    t.set("B1", "=B2");
    t.set("B2", "=B1");
    assert!(t.get("B1").is_error());
    t.set("C1", "=NOSUCHFN(1)");
    assert_eq!(t.get("C1"), Value::Error(CellError::Name));
    t.set("C2", "=1+");
    assert_eq!(t.get("C2"), Value::Error(CellError::Name));
}

#[test]
fn operators() {
    let mut t = T::new();
    t.set("A1", "=\"a\"&1&TRUE");
    assert_eq!(t.get("A1"), Value::from("a1TRUE"));
    t.set("A2", "=-2^2");
    assert_eq!(t.num("A2"), 4.0);
    t.set("A3", "=50%");
    assert_eq!(t.num("A3"), 0.5);
    t.set("A4", "=\"abc\"=\"ABC\"");
    assert_eq!(t.get("A4"), Value::Bool(true));
    t.set("A5", "=\"5\"+1");
    assert_eq!(t.num("A5"), 6.0);
    t.set("A6", "=\"x\"+1");
    assert_eq!(t.get("A6"), Value::Error(CellError::Value));
    t.set("A7", "=B99");
    assert_eq!(t.num("A7"), 0.0);
}

#[test]
fn blocked_spill_reads_as_spill_error() {
    // Calculated in the same pass, a formula over a blocked spill read the array that couldn't
    // spill.
    let mut t = T::new();
    let s = t.wb.sheet_mut(0).unwrap();
    for a in ["A1", "B1", "C1", "A2", "C2", "A3", "B3", "C3"] {
        s.cells.set(c(a), Cell::value(Value::Number(1.0)));
    }
    s.cells.set(c("B2"), Cell::formula(Formula::new("=SEQUENCE(2,2,9)")));
    s.cells.set(c("E1"), Cell::formula(Formula::new("=SUM(A1:C3)")));
    t.calc.recalc_all(&mut t.wb);
    assert_eq!(t.get("B2"), Value::Error(CellError::Spill));
    assert_eq!(t.get("E1"), Value::Error(CellError::Spill));
    assert_eq!(t.num("C3"), 1.0);
}

#[test]
fn blocked_spill_read_through_offset() {
    // The reader's reference is only known while evaluating, so it isn't in the dependency graph.
    let mut t = T::new();
    t.set("E4", "5");
    t.set("E8", "=SUM(OFFSET(E2,0,0,2,2))");
    t.set("E3", "=SEQUENCE(2,2,3)");
    t.calc.recalc_all(&mut t.wb);
    assert_eq!(t.get("E3"), Value::Error(CellError::Spill));
    assert_eq!(t.get("E8"), Value::Error(CellError::Spill));
}

#[test]
fn spill_into_the_old_area_of_a_blocked_neighbour() {
    // C7's array becomes blocked by C8, whose array then takes over C7's old area.
    let mut t = T::new();
    t.set("C7", "=SEQUENCE(2,2)");
    t.set("C8", "=SEQUENCE(2,2)");
    assert_eq!(t.get("C7"), Value::Error(CellError::Spill));
    assert_eq!([t.num("C8"), t.num("D8"), t.num("C9"), t.num("D9")], [1.0, 2.0, 3.0, 4.0]);
}

#[test]
fn arrays_do_not_spill_in_tables() {
    // Excel: spilled array formulas aren't supported in tables.
    let mut t = T::new();
    t.wb.sheet_mut(0).unwrap().tables.push(gridcraft_model::Table {
        id: 1,
        name: "Table1".into(),
        range: gridcraft_core::RangeRef::parse("B3:C6").unwrap(),
        header_row: true,
        totals_row: false,
        columns: vec![],
        style: String::new(),
        banded_rows: false,
        banded_cols: false,
        first_col: false,
        last_col: false,
        filter_button: false,
    });
    t.set("C4", "=SEQUENCE(2)");
    t.set("E1", "=SEQUENCE(4)");
    t.set("H1", "=SUM(C4:C5)");
    assert_eq!(t.get("C4"), Value::Error(CellError::Spill));
    assert_eq!(t.get("C5"), Value::Empty);
    assert_eq!(t.get("H1"), Value::Error(CellError::Spill));
    assert_eq!(t.num("E4"), 4.0);
}

#[test]
fn ifs_and_lazy() {
    let mut t = T::new();
    t.set("A1", "5");
    t.set("B1", "=IF(A1>3,\"big\",1/0)");
    assert_eq!(t.get("B1"), Value::from("big"));
    t.set("B2", "=IFERROR(1/0,\"oops\")");
    assert_eq!(t.get("B2"), Value::from("oops"));
    t.set("B3", "=CHOOSE(2,\"a\",\"b\",\"c\")");
    assert_eq!(t.get("B3"), Value::from("b"));
    t.set("B4", "=SWITCH(A1,1,\"one\",5,\"five\",\"other\")");
    assert_eq!(t.get("B4"), Value::from("five"));
}

#[test]
fn choose_with_an_array_index() {
    let mut t = T::new();
    for (i, (k, v)) in [(1, 10), (2, 20), (3, 30)].iter().enumerate() {
        t.set(&format!("A{}", i + 1), &k.to_string());
        t.set(&format!("B{}", i + 1), &v.to_string());
    }
    t.set("D1", "=CHOOSE({1,2},\"a\",\"b\")");
    assert_eq!(t.get("D1"), Value::from("a"));
    assert_eq!(t.get("E1"), Value::from("b"));
    // The usual "look left" idiom: a two-column array from two ranges.
    t.set("D3", "=VLOOKUP(20,CHOOSE({1,2},B1:B3,A1:A3),2,FALSE)");
    assert_eq!(t.num("D3"), 2.0);
    t.set("D4", "=SUM(CHOOSE({1,2},A1:A3,B1:B3))");
    assert_eq!(t.num("D4"), 66.0);
    t.set("D5", "=CHOOSE(2,A1:A3,B1:B3)");
    assert_eq!(t.num("D7"), 30.0);
}

#[test]
fn references_functions() {
    let mut t = T::new();
    for (i, v) in [10, 20, 30, 40].iter().enumerate() {
        t.set(&format!("A{}", i + 1), &v.to_string());
    }
    t.set("B1", "=ROW(A3)");
    assert_eq!(t.num("B1"), 3.0);
    t.set("B2", "=ROWS(A1:A4)*COLUMNS(A1:C1)");
    assert_eq!(t.num("B2"), 12.0);
    t.set("B3", "=SUM(OFFSET(A1,1,0,2,1))");
    assert_eq!(t.num("B3"), 50.0);
    t.set("B4", "=INDIRECT(\"A\"&4)");
    assert_eq!(t.num("B4"), 40.0);
    t.set("B5", "=SUM(A1:INDEX(A1:A4,3))");
    assert_eq!(t.num("B5"), 60.0);
    t.set("B6", "=SUM(A:A)");
    assert_eq!(t.num("B6"), 100.0);
    t.set("A2", "25");
    assert_eq!(t.num("B3"), 55.0);
    assert_eq!(t.num("B6"), 105.0);
}

#[test]
fn relative_names() {
    let mut t = T::new();
    // As files store them: relative to A1. `Left` is the cell to the left, `Above3` the three
    // cells above, `Mixed` column A of the same row.
    for (name, formula) in [("Left", "Sheet1!XFD1"), ("Above3", "Sheet1!A1048574:A1048576"), ("Mixed", "Sheet1!$A1")] {
        t.wb.names.push(gridcraft_model::DefinedName {
            name: name.into(),
            scope: None,
            formula: formula.into(),
            comment: String::new(),
            hidden: false,
        });
    }
    t.calc.rebuild(&t.wb);
    for r in 1..=5 {
        t.set(&format!("A{r}"), &(r * 10).to_string());
    }
    t.set("B2", "=Left");
    assert_eq!(t.num("B2"), 20.0);
    t.set("B4", "=Left+Mixed");
    assert_eq!(t.num("B4"), 80.0);
    t.set("A6", "=SUM(Above3)");
    assert_eq!(t.num("A6"), 120.0);
}

#[test]
fn spills() {
    let mut t = T::new();
    t.set("A1", "=SEQUENCE(3)");
    assert_eq!(t.num("A1"), 1.0);
    assert_eq!(t.num("A3"), 3.0);
    t.set("B1", "=SUM(A1:A3)");
    assert_eq!(t.num("B1"), 6.0);
    t.set("A2", "x");
    assert_eq!(t.get("A1"), Value::Error(CellError::Spill));
    t.set("A2", "");
    assert_eq!(t.num("A3"), 3.0);
    t.set("C1", "={1,2;3,4}*10");
    assert_eq!(t.num("D2"), 40.0);
}

#[test]
fn references_keep_their_size_past_the_used_range() {
    let mut t = T::new();
    t.set("A1", "5");
    t.set("A2", "6");
    t.set("C1", "=ROWS(A1:A10*1)");
    t.set("C2", "=SUMPRODUCT(--(A1:A10=\"\"))");
    t.set("C3", "=COUNTBLANK(A1:A10)");
    t.set("C4", "=COUNTIF(A1:A10,\"\")");
    t.set("C5", "=COLUMNS(TRANSPOSE(A1:A10))");
    for (at, want) in [("C1", 10.0), ("C2", 8.0), ("C3", 8.0), ("C4", 8.0), ("C5", 10.0)] {
        assert_eq!(t.num(at), want, "{at}");
    }
    // Whole columns are still read up to the used range.
    t.set("D1", "=ROWS(FILTER(A:A,A:A<>\"\"))");
    assert_eq!(t.num("D1"), 2.0);
}

#[test]
fn spilled_blank_cells_show_zero() {
    let mut t = T::new();
    t.set("A1", "5");
    t.set("A3", "7");
    t.set("C1", "=A1:A4");
    assert_eq!(t.get("C2"), Value::Number(0.0));
    assert_eq!(t.get("C4"), Value::Number(0.0));
    t.set("D1", "=COUNT(C1:C4)");
    assert_eq!(t.num("D1"), 4.0);
    t.set("E1", "=A2:A3");
    assert_eq!(t.get("E1"), Value::Number(0.0));
    t.set("F1", "=SORT(A1:A3)");
    assert_eq!(t.get("F3"), Value::Number(0.0));
}

#[test]
fn let_lambda() {
    let mut t = T::new();
    t.set("A1", "=LET(x,2,y,3,x*y)");
    assert_eq!(t.num("A1"), 6.0);
    t.set("A2", "=LAMBDA(a,b,a+b)(2,3)");
    assert_eq!(t.num("A2"), 5.0);
    t.set("A3", "=REDUCE(0,{1,2,3},LAMBDA(acc,v,acc+v))");
    assert_eq!(t.num("A3"), 6.0);
    t.set("A4", "=SUM(MAP({1,2,3},LAMBDA(v,v*v)))");
    assert_eq!(t.num("A4"), 14.0);
}

#[test]
fn names_and_sheets() {
    let mut t = T::new();
    t.wb.names.push(gridcraft_model::DefinedName { name: "Rate".into(), scope: None, formula: "0.5".into(), comment: String::new(), hidden: false });
    t.wb.sheets.push(std::sync::Arc::new(gridcraft_model::Sheet::new("Data")));
    t.wb.sheet_mut(1).unwrap().set_value(c("A1"), Value::Number(8.0));
    t.calc.rebuild(&t.wb);
    t.set("A1", "=Rate*Data!A1");
    assert_eq!(t.num("A1"), 4.0);
    t.wb.sheet_mut(1).unwrap().set_value(c("A1"), Value::Number(10.0));
    t.calc.cells_changed(&mut t.wb, &[(1, c("A1"))]);
    assert_eq!(t.num("A1"), 5.0);
}

#[test]
fn legacy_array_formulas_fill_their_range() {
    let mut t = T::new();
    t.set("A1", "1");
    t.set("A2", "2");
    let cse = |t: &mut T, at: &str, formula: &str, range: &str| {
        let mut f = Formula::new(formula);
        f.array = gridcraft_core::RangeRef::parse(range);
        t.wb.sheet_mut(0).unwrap().cells.set(c(at), Cell::formula(f));
        t.calc.cells_changed(&mut t.wb, &[(0, c(at))]);
    };
    // Past the result: #N/A. A single column repeats across the range.
    cse(&mut t, "C1", "=A1:A2*2", "C1:D3");
    cse(&mut t, "F1", "=A1:A2*2", "F1");
    cse(&mut t, "G1", "=5", "G1:G2");
    assert_eq!(t.num("C2"), 4.0);
    assert_eq!(t.num("D2"), 4.0);
    assert_eq!(t.get("C3"), Value::Error(CellError::NA));
    // A smaller range shows only part of the result and never spills.
    assert_eq!(t.num("F1"), 2.0);
    assert_eq!(t.get("F2"), Value::Empty);
    assert_eq!(t.num("G2"), 5.0);
    // A range too large to fill is an error, not an allocation of every cell.
    cse(&mut t, "H1", "=1", "H1:XFD1048576");
    assert_eq!(t.get("H1"), Value::Error(CellError::Num));
}

#[test]
fn text_function() {
    let mut t = T::new();
    t.set("A1", "=TEXT(1234.5,\"#,##0.00\")");
    assert_eq!(t.get("A1"), Value::from("1,234.50"));
}

#[test]
fn subtotal_skips_hidden() {
    let mut t = T::new();
    t.set("A1", "1");
    t.set("A2", "2");
    t.set("A3", "3");
    t.wb.sheet_mut(0).unwrap().rows.insert(1, gridcraft_model::LineInfo { hidden: true, ..Default::default() });
    t.set("B1", "=SUBTOTAL(109,A1:A3)");
    t.set("B2", "=SUBTOTAL(9,A1:A3)");
    assert_eq!(t.num("B1"), 4.0);
    assert_eq!(t.num("B2"), 6.0);
}

#[test]
fn recalc_all_after_load() {
    let mut t = T::new();
    let s = t.wb.sheet_mut(0).unwrap();
    s.cells.set(c("A1"), Cell::value(Value::Number(4.0)));
    s.cells.set(c("A2"), Cell::formula(Formula::new("=A1*2")));
    s.cells.set(c("A3"), Cell::formula(Formula::new("=A2+A1")));
    t.calc.recalc_all(&mut t.wb);
    assert_eq!(t.num("A3"), 12.0);
}

#[test]
fn sumif_sum_range_takes_the_criteria_size() {
    // Excel adds up the range that starts at sum_range's top-left cell with the criteria range's
    // height and width, whatever size sum_range has.
    let mut t = T::new();
    for (r, (k, v)) in [("a", 1), ("b", 2), ("a", 3)].iter().enumerate() {
        t.set(&format!("A{}", r + 1), k);
        t.set(&format!("B{}", r + 1), &v.to_string());
    }
    t.set("D1", "=SUMIF(A1:A3,\"a\",B1)");
    assert_eq!(t.num("D1"), 4.0);
    t.set("D2", "=AVERAGEIF(A1:A3,\"a\",B1)");
    assert_eq!(t.num("D2"), 2.0);
    t.set("D3", "=SUMIF(A1:A3,\"a\",B1:B2)");
    assert_eq!(t.num("D3"), 4.0);
    t.set("D4", "=SUMIF(A1:A3,\"a\",B1:F1)");
    assert_eq!(t.num("D4"), 4.0);
    t.set("D5", "=SUMIF(A1:A3,\"a\",B1:B99)");
    assert_eq!(t.num("D5"), 4.0);
    t.set("D6", "=SUMIF(A:A,\"a\",B1)");
    assert_eq!(t.num("D6"), 4.0);
    t.set("D7", "=SUMIF(A1:A3,\"a\",$B$2)");
    assert_eq!(t.num("D7"), 2.0); // B2:B4: rows 1 and 3 match → B2 + B4 (empty)
    t.set("D8", "=SUMIF(A1:A3,\"a\")");
    assert_eq!(t.num("D8"), 0.0);
    // A horizontal criteria range resizes across.
    t.set("H1", "1");
    t.set("I1", "0");
    t.set("J1", "1");
    t.set("H2", "10");
    t.set("I2", "20");
    t.set("J2", "30");
    t.set("D9", "=SUMIF(H1:J1,1,H2)");
    assert_eq!(t.num("D9"), 40.0);
    // The resized cells are precedents: editing one recalculates.
    t.set("B3", "5");
    assert_eq!(t.num("D1"), 6.0);
    assert_eq!(t.num("D2"), 3.0);
    assert_eq!(t.num("D3"), 6.0);
    assert_eq!(t.num("D4"), 6.0);
    assert_eq!(t.num("D6"), 6.0);
    // SUMIFS and AVERAGEIFS don't resize: different sizes are #VALUE!.
    t.set("D11", "=SUMIFS(B1,A1:A3,\"a\")");
    assert_eq!(t.get("D11"), Value::Error(CellError::Value));
    t.set("D12", "=AVERAGEIFS(B1:B2,A1:A3,\"a\")");
    assert_eq!(t.get("D12"), Value::Error(CellError::Value));
    t.set("D13", "=SUMIFS(B1:B3,A1:A3,\"a\")");
    assert_eq!(t.num("D13"), 6.0);
}

#[test]
fn sumif_resized_sum_range_stops_at_the_sheet_edge() {
    let mut t = T::new();
    t.set("A1", "a");
    t.set("A2", "a");
    t.set("B1048575", "5");
    t.set("B1048576", "7");
    t.set("C1", "=SUMIF(A1:A2,\"a\",B1048576)");
    assert_eq!(t.num("C1"), 7.0);
    t.set("C2", "=SUMIF(A1:A2,\"a\",B1048575)");
    assert_eq!(t.num("C2"), 12.0);
    t.set("C3", "=SUMIF(A1:B1,\"a\",XFD1)");
    assert_eq!(t.num("C3"), 0.0);
}

#[test]
fn sumif_resized_sum_range_on_another_sheet_and_through_a_name() {
    let mut t = T::new();
    t.wb.sheets.push(std::sync::Arc::new(gridcraft_model::Sheet::new("Data")));
    t.wb.names.push(gridcraft_model::DefinedName {
        name: "Amounts".into(),
        scope: None,
        formula: "Data!$B$1".into(),
        comment: String::new(),
        hidden: false,
    });
    for (r, k) in ["a", "b", "a"].iter().enumerate() {
        t.set(&format!("A{}", r + 1), k);
        t.wb.sheet_mut(1).unwrap().set_value(CellRef::new(r as u32, 1), Value::Number((r + 1) as f64));
    }
    t.calc.rebuild(&t.wb);
    t.set("C1", "=SUMIF(A1:A3,\"a\",Data!B1)");
    assert_eq!(t.num("C1"), 4.0);
    t.set("C2", "=AVERAGEIF(A1:A3,\"a\",Amounts)");
    assert_eq!(t.num("C2"), 2.0);
    t.wb.sheet_mut(1).unwrap().set_value(c("B3"), Value::Number(9.0));
    t.calc.cells_changed(&mut t.wb, &[(1, c("B3"))]);
    assert_eq!(t.num("C1"), 10.0);
    assert_eq!(t.num("C2"), 5.0);
}

#[test]
fn trimrange() {
    let mut t = T::new();
    t.set("C3", "1");
    t.set("D5", "2");
    let cases = [
        ("J1", "=ROWS(TRIMRANGE(A1:F10))", 3.0),
        ("J2", "=COLUMNS(TRIMRANGE(A1:F10))", 2.0),
        ("J3", "=ROWS(TRIMRANGE(A1:F10,2))", 5.0),
        ("J4", "=ROWS(TRIMRANGE(A1:F10,1,0))", 8.0),
        ("J5", "=COLUMNS(TRIMRANGE(A1:F10,1,0))", 6.0),
        ("J6", "=ROWS(TRIMRANGE(A1:F10,0,0))", 10.0),
        ("J7", "=SUM(TRIMRANGE(C:C))", 1.0),
        ("J8", "=ROWS(TRIMRANGE(C:C))", 1.0),
        ("J9", "=ROWS(TRIMRANGE(C:C,2))", 3.0),
        ("J10", "=MIN(ROW(TRIMRANGE(A1:F10)))", 3.0),
        ("J11", "=COLUMNS(TRIMRANGE({1,2;3,4}))", 2.0),
    ];
    for (at, f, _) in cases {
        t.set(at, f);
    }
    for (at, f, want) in cases {
        assert_eq!(t.num(at), want, "{f}");
    }
    // The result spills as the trimmed block and follows edits.
    t.set("L1", "=TRIMRANGE(A1:F10)");
    assert_eq!((t.num("L1"), t.num("M3")), (1.0, 2.0));
    t.set("E6", "3");
    assert_eq!((t.num("J1"), t.num("J2")), (4.0, 3.0));
    // Errors: a bad trim code, nothing but blanks, several areas.
    t.set("K1", "=TRIMRANGE(A1:F10,4)");
    assert_eq!(t.get("K1"), Value::Error(CellError::Value));
    t.set("K2", "=TRIMRANGE(Q1:Q9)");
    assert_eq!(t.get("K2"), Value::Error(CellError::Calc));
    t.set("K3", "=TRIMRANGE((A1:B2,C3:D4))");
    assert_eq!(t.get("K3"), Value::Error(CellError::Value));
}

/// `formula` in AB1 over a small mixed sheet. The ranges in the cases below are cut from it:
///
/// ```text
///      A      B      C       E
///  1   1.5    10     =A1*4        (C1 is a formula cell inside the ranges)
///  2   2      TRUE           #DIV/0!   (E2 only when `error` is set)
///  3   text   3
///  4   -0.25
/// ```
fn aggregate_of(error: bool, formula: &str) -> Value {
    let mut t = T::new();
    for (at, v) in [("A1", "1.5"), ("A2", "2"), ("A3", "skipped"), ("A4", "-0.25"), ("B1", "10"), ("B2", "TRUE"), ("B3", "3"), ("C1", "=A1*4")] {
        t.set(at, v);
    }
    if error {
        t.set("E2", "#DIV/0!");
    }

    // AB1 is outside every range used, so the formula can't read itself.
    t.set("AB1", formula);
    t.get("AB1")
}

#[test]
fn sum_count_average_over_ranges() {
    // Text, booleans, blanks and a formula cell inside ranges; direct arguments; unions; whole
    // columns; blocks holding an error or nothing numeric. The expected values are what the
    // array path (the ranges copied into an array) gave before the ranges were folded in place,
    // so any difference is a change of behavior.
    let n = Value::Number;
    let e = Value::Error;

    // (formula written with SUM, error in E2?, [SUM, COUNT, AVERAGE] of that formula)
    #[rustfmt::skip]
    let cases: &[(&str, bool, [Value; 3])] = &[
        ("=SUM(A1:A1,B3)", false, [n(4.5), n(2.0), n(2.25)]),
        ("=SUM(A1:A1,B3)", true, [n(4.5), n(2.0), n(2.25)]),
        ("=SUM((A1:A2,B1:B3))", false, [n(16.5), n(4.0), n(4.125)]),
        ("=SUM((A1:A2,B1:B3))", true, [n(16.5), n(4.0), n(4.125)]),
        ("=SUM(A1:A4,B1:B3)", false, [n(16.25), n(5.0), n(3.25)]),
        ("=SUM(A1:A4,B1:B3)", true, [n(16.25), n(5.0), n(3.25)]),
        ("=SUM(A1:A4,\"x\")", false, [e(CellError::Value), n(3.0), e(CellError::Value)]),
        ("=SUM(A1:A4,\"x\")", true, [e(CellError::Value), n(3.0), e(CellError::Value)]),
        ("=SUM(A1:B4,5,\"7\",TRUE)", false, [n(29.25), n(8.0), n(3.65625)]),
        ("=SUM(A1:B4,5,\"7\",TRUE)", true, [n(29.25), n(8.0), n(3.65625)]),
        ("=SUM(A1:C4)+SUM(B1:B3)", false, [n(35.25), n(8.0), n(10.208333333333334)]),
        ("=SUM(A1:C4)+SUM(B1:B3)", true, [n(35.25), n(8.0), n(10.208333333333334)]),
        ("=SUM(A1:C4)", false, [n(22.25), n(6.0), n(3.7083333333333335)]),
        ("=SUM(A1:C4)", true, [n(22.25), n(6.0), n(3.7083333333333335)]),
        ("=SUM(A1:E4)", false, [n(22.25), n(6.0), n(3.7083333333333335)]),
        ("=SUM(A1:E4)", true, [e(CellError::Div0), n(6.0), e(CellError::Div0)]),
        ("=SUM(A1)", false, [n(1.5), n(1.0), n(1.5)]),
        ("=SUM(A1)", true, [n(1.5), n(1.0), n(1.5)]),
        ("=SUM(A3,B2)", false, [n(0.0), n(0.0), e(CellError::Div0)]),
        ("=SUM(A3,B2)", true, [n(0.0), n(0.0), e(CellError::Div0)]),
        ("=SUM(A:C)", false, [n(22.25), n(6.0), n(3.7083333333333335)]),
        ("=SUM(A:C)", true, [n(22.25), n(6.0), n(3.7083333333333335)]),
        ("=SUM(E1:E3)", false, [n(0.0), n(0.0), e(CellError::Div0)]),
        ("=SUM(E1:E3)", true, [e(CellError::Div0), n(0.0), e(CellError::Div0)]),
        ("=SUM(Z1:Z9)", false, [n(0.0), n(0.0), e(CellError::Div0)]),
        ("=SUM(Z1:Z9)", true, [n(0.0), n(0.0), e(CellError::Div0)]),
    ];

    for (formula, error, want) in cases {
        for (func, want) in ["SUM", "COUNT", "AVERAGE"].into_iter().zip(want) {
            // The same formula for each function: `SUM(` becomes `COUNT(` or `AVERAGE(`.
            let f = formula.replace("SUM", func);

            assert_eq!(&aggregate_of(*error, &f), want, "{f} (error in E2: {error})");
        }
    }
}

#[test]
fn sum_count_average_have_no_size_limit() {
    // One stored cell far down stretches the used range to 27 million cells (27 columns by a
    // million rows), past the 16M-cell limit of ranges copied into an array. Only two cells are
    // stored, so the sheet itself is tiny.
    for (func, want) in [("SUM", Value::Number(2.5)), ("COUNT", Value::Number(2.0)), ("AVERAGE", Value::Number(1.25))] {
        for range in ["A1:AA1000000", "A:AA"] {
            let mut t = T::new();
            t.set("A1", "1.5");
            t.set("Z1000000", "1");

            t.set("AB1", &format!("={func}({range})"));

            assert_eq!(t.get("AB1"), want, "{func}({range})");
        }
    }
}

#[test]
fn sum_count_average_over_spilled_values() {
    // A1 spills over A1:A3, so the block holds values that exist only as a spill (they have no
    // stored cell of their own). The host must not fold such a block in place: it falls back
    // to the array path, which sees the spill. Expected: 1 + 2 + 3 + 10.
    let mut t = T::new();
    t.set("A1", "=SEQUENCE(3)");
    t.set("A4", "10");

    for (f, want) in [("SUM", 16.0), ("COUNT", 4.0), ("AVERAGE", 4.0)] {
        t.set("C1", &format!("={f}(A1:A5)"));

        assert_eq!(t.num("C1"), want, "{f}");
    }
}

#[test]
fn aggregate_arguments_are_read_in_order() {
    // Volatile cells draw a random number each time they are calculated, so the order in which
    // the arguments are read decides which draw each one gets. `B1:B2` comes first, so B2 must
    // draw before the `RAND()` argument does. (Reading the plain `RAND()` first once gave
    // 7.9043 here.) The expected values are what the array path gave; they depend on the random
    // generator and its seed, and must be updated if either changes.
    let mut t = T::new();
    t.set("B1", "1");
    t.set("B2", "=RAND()*10");

    t.set("A1", "=SUM(B1:B2,RAND())");

    assert_eq!((t.num("A1"), t.num("B2")), (4.968520165759784, 3.3112028100185356));
}

#[test]
fn sum_count_average_follow_edits_inside_the_range() {
    // A range read in place must still count as a precedent of the formula: if it didn't, an
    // edit inside it would leave the formula showing a stale value. Each step below changes one
    // cell inside the range and checks all three functions; the last one changes a cell outside.
    for range in ["A1:A5", "A:A"] {
        let mut t = T::new();
        t.set("A1", "1");
        t.set("A3", "3");
        t.set("C1", &format!("=SUM({range})"));
        t.set("C2", &format!("=COUNT({range})"));
        t.set("C3", &format!("=AVERAGE({range})"));
        let all = |t: &T| (t.num("C1"), t.num("C2"), t.num("C3"));
        assert_eq!(all(&t), (4.0, 2.0, 2.0), "{range}");

        t.set("A1", "5");
        assert_eq!(all(&t), (8.0, 2.0, 4.0), "{range}: edit");

        t.set("A2", "10");
        assert_eq!(all(&t), (18.0, 3.0, 6.0), "{range}: fill a blank");

        t.set("A3", "text");
        assert_eq!(all(&t), (15.0, 2.0, 7.5), "{range}: number to text");

        t.set("A2", "");
        assert_eq!(all(&t), (5.0, 1.0, 5.0), "{range}: clear");

        t.set("A5", "=A1*2");
        assert_eq!(all(&t), (15.0, 2.0, 7.5), "{range}: formula in the range");

        t.set("A1", "1");
        assert_eq!(all(&t), (3.0, 2.0, 1.5), "{range}: its precedent changes");

        // A7 is inside the whole column A:A but outside A1:A5.
        t.set("A7", "100");
        let outside = if range == "A:A" { (103.0, 3.0, 103.0 / 3.0) } else { (3.0, 2.0, 1.5) };
        assert_eq!(all(&t), outside, "{range}: a cell outside the range");
    }
}

#[test]
fn visit_range_declines_when_a_formula_in_the_block_spills_into_it() {
    // The sheet: D1 = SEQUENCE(3) and D4 = 10, and D1 has not been calculated yet when the
    // block D1:D5 is read.
    let mut wb = Workbook::new();
    let sh = wb.sheet_mut(0).unwrap();
    sh.cells.set(c("D1"), Cell::formula(Formula::new("=SEQUENCE(3)")));
    sh.cells.set(c("D4"), Cell::value(Value::Number(10.0)));
    let block = gridcraft_core::RangeRef::parse("D1:D5").unwrap();

    // Reading the block calculates D1, which spills over D2:D3. A walk over the stored cells
    // would never see 2 and 3, so the host must decline and leave the block to `range_values`.
    // (`Calc` recalculates a pass that produced new spills, so final results are right either
    // way; only this direct call shows the host's contract.)
    let walked = crate::recalc::tests::probe_visit_range(&wb, &[("D1", "=SEQUENCE(3)")], block);

    assert_eq!(walked, None, "walked a block holding a spill it can't see");
}