const std = @import("std");
const pi = @import("program_index.zig");
const ProgramIndex = pi.ProgramIndex;
const ast = @import("../ast.zig");
const types = @import("types.zig");
const inst = @import("inst.zig");

test "ProgramIndex.init starts empty with unset borrowed views" {
    var idx = ProgramIndex.init(std.testing.allocator);
    defer idx.deinit();
    try std.testing.expectEqual(@as(u32, 0), idx.import_flags.count());
    try std.testing.expect(idx.module_scopes == null);
    try std.testing.expect(idx.import_graph == null);
}

test "ProgramIndex.import_flags round-trips imported vs local" {
    var idx = ProgramIndex.init(std.testing.allocator);
    defer idx.deinit();
    try idx.import_flags.put("printf", true);
    try idx.import_flags.put("main", false);
    try std.testing.expectEqual(@as(?bool, true), idx.import_flags.get("printf"));
    try std.testing.expectEqual(@as(?bool, false), idx.import_flags.get("main"));
    try std.testing.expect(idx.import_flags.get("absent") == null);
}

test "ProgramIndex borrows module_scopes / import_graph without owning them" {
    const ScopeSet = std.StringHashMap(std.StringHashMap(void));
    var scopes = ScopeSet.init(std.testing.allocator);
    defer scopes.deinit();
    var graph = ScopeSet.init(std.testing.allocator);
    defer graph.deinit();

    var idx = ProgramIndex.init(std.testing.allocator);
    defer idx.deinit();
    idx.module_scopes = &scopes;
    idx.import_graph = &graph;

    // Reads go through the borrowed pointer; the backing stays caller-owned,
    // so idx.deinit() must not free it (testing.allocator would flag a
    // double-free / leak otherwise).
    try std.testing.expect(idx.module_scopes.? == &scopes);
    try std.testing.expect(idx.import_graph.? == &graph);
    try std.testing.expectEqual(@as(u32, 0), idx.module_scopes.?.count());
}

test "ProgramIndex declaration maps round-trip (A1.1b)" {
    var idx = ProgramIndex.init(std.testing.allocator);
    defer idx.deinit();

    // Minimal AST node reused wherever a *Node is required.
    var blk = ast.Node{ .span = .{ .start = 0, .end = 0 }, .data = .{ .block = .{ .stmts = &.{} } } };

    // fn_ast_map: function name → AST decl.
    const fd = ast.FnDecl{ .name = "main", .params = &.{}, .return_type = null, .body = &blk };
    try idx.fn_ast_map.put("main", &fd);
    try std.testing.expect(idx.fn_ast_map.get("main").? == &fd);

    // type_alias_map: alias name → target TypeId.
    try idx.type_alias_map.put("ShaderHandle", .s64);
    try std.testing.expectEqual(@as(?types.TypeId, .s64), idx.type_alias_map.get("ShaderHandle"));

    // global_names: #run global name → GlobalInfo.
    try idx.global_names.put("g", .{ .id = inst.GlobalId.fromIndex(0), .ty = .s64 });
    try std.testing.expect(idx.global_names.get("g").?.id == inst.GlobalId.fromIndex(0));

    // module_const_map: const name → ModuleConstInfo.
    try idx.module_const_map.put("AF_INET", .{ .value = &blk, .ty = .s32 });
    try std.testing.expect(idx.module_const_map.get("AF_INET").?.value == &blk);

    // foreign_class_map: sx alias → ForeignClassDecl.
    const fcd = ast.ForeignClassDecl{
        .name = "NSString",
        .foreign_path = "NSString",
        .runtime = .objc_class,
        .members = &.{},
        .is_foreign = true,
        .is_main = false,
    };
    try idx.foreign_class_map.put("NSString", &fcd);
    try std.testing.expect(idx.foreign_class_map.get("NSString").? == &fcd);

    // protocol_decl_map: protocol name → ProtocolDeclInfo.
    try idx.protocol_decl_map.put("Show", .{ .name = "Show", .is_inline = false, .methods = &.{} });
    try std.testing.expectEqualStrings("Show", idx.protocol_decl_map.get("Show").?.name);

    // protocol_ast_map: protocol name → AST decl.
    const pd = ast.ProtocolDecl{ .name = "Show", .methods = &.{} };
    try idx.protocol_ast_map.put("Show", &pd);
    try std.testing.expect(idx.protocol_ast_map.get("Show").? == &pd);

    // struct_template_map: generic struct name → template.
    try idx.struct_template_map.put("List", .{ .name = "List", .type_params = &.{}, .field_names = &.{}, .field_type_nodes = &.{} });
    try std.testing.expectEqualStrings("List", idx.struct_template_map.get("List").?.name);

    // ufcs_alias_map: alias name → target function name.
    try idx.ufcs_alias_map.put("len", "list_len");
    try std.testing.expectEqualStrings("list_len", idx.ufcs_alias_map.get("len").?);
}

/// Stand-in for the leaf-name lookup both array-dimension resolvers pass to the
/// shared `evalConstIntExpr`: `M`/`N` resolve to integers, everything else is
/// genuinely non-comptime.
const DimCtx = struct {
    pub fn lookupDimName(_: DimCtx, name: []const u8) ?i64 {
        if (std.mem.eql(u8, name, "M")) return 4;
        if (std.mem.eql(u8, name, "N")) return 6;
        return null;
    }
};

fn nLit(v: i64) ast.Node {
    return .{ .span = .{ .start = 0, .end = 0 }, .data = .{ .int_literal = .{ .value = v } } };
}
fn nIdent(name: []const u8) ast.Node {
    return .{ .span = .{ .start = 0, .end = 0 }, .data = .{ .identifier = .{ .name = name } } };
}
fn nBin(op: ast.BinaryOp.Op, l: *ast.Node, r: *ast.Node) ast.Node {
    return .{ .span = .{ .start = 0, .end = 0 }, .data = .{ .binary_op = .{ .op = op, .lhs = l, .rhs = r } } };
}
fn nNeg(operand: *ast.Node) ast.Node {
    return .{ .span = .{ .start = 0, .end = 0 }, .data = .{ .unary_op = .{ .op = .negate, .operand = operand } } };
}

test "evalConstIntExpr folds constant-expression array dimensions, halts on non-const" {
    const eval = pi.evalConstIntExpr;
    const ctx = DimCtx{};

    var l5 = nLit(5);
    var one = nLit(1);
    var two = nLit(2);
    var zero = nLit(0);
    var m = nIdent("M");
    var n = nIdent("N");
    var z = nIdent("Z"); // unbound — genuinely non-comptime

    // Leaves: literal, named const, unbound name.
    try std.testing.expectEqual(@as(?i64, 5), eval(&l5, ctx));
    try std.testing.expectEqual(@as(?i64, 4), eval(&m, ctx));
    try std.testing.expect(eval(&z, ctx) == null);

    // `M + 1`, `M * N`, `N - M`.
    var add = nBin(.add, &m, &one);
    var mul = nBin(.mul, &m, &n);
    var sub = nBin(.sub, &n, &m);
    try std.testing.expectEqual(@as(?i64, 5), eval(&add, ctx));
    try std.testing.expectEqual(@as(?i64, 24), eval(&mul, ctx));
    try std.testing.expectEqual(@as(?i64, 2), eval(&sub, ctx));

    // Nested `(M + N) - 1` and parenthesised `(M + 1) * 2` (parens carry no node).
    var addmn = nBin(.add, &m, &n);
    var nested = nBin(.sub, &addmn, &one);
    var paren = nBin(.mul, &add, &two);
    try std.testing.expectEqual(@as(?i64, 9), eval(&nested, ctx));
    try std.testing.expectEqual(@as(?i64, 10), eval(&paren, ctx));

    // Unary negate.
    var neg = nNeg(&m);
    try std.testing.expectEqual(@as(?i64, -4), eval(&neg, ctx));

    // Genuinely non-const operand, division by zero, a non-arithmetic operator,
    // and overflow all yield null → the caller's clean compile-halt (no panic,
    // no fabricated length).
    var addz = nBin(.add, &m, &z);
    var divz = nBin(.div, &m, &zero);
    var cmp = nBin(.lt, &m, &n);
    var big = nLit(std.math.maxInt(i64));
    var ovf = nBin(.mul, &big, &two);
    try std.testing.expect(eval(&addz, ctx) == null);
    try std.testing.expect(eval(&divz, ctx) == null);
    try std.testing.expect(eval(&cmp, ctx) == null);
    try std.testing.expect(eval(&ovf, ctx) == null);
}