alef 0.80.0

use crate::e2e::codegen::assertion_type_skip::{
    streaming_assertion_type_skip_line, streaming_assertion_value_skip_line,
};
use crate::e2e::codegen::field_skip::{FieldSkip, nested_wildcard_skip_line};
use crate::e2e::codegen::payload_union_skip::{UnionLoweringTarget, payload_union_skip_line};
use crate::e2e::field_access::FieldResolver;
use crate::e2e::fixture::Assertion;
use heck::ToLowerCamelCase;
use std::fmt::Write as FmtWrite;

use super::values::escape_dart;

mod tagged_union;

use tagged_union::try_render_tagged_union_assertion;

/// ~keep The token a skip marker names when the assertion carries no field path. Every registered
/// wording quotes a token, so a marker that quotes nothing matches no shape and stays invisible to
/// both funnels.
const BARE_RESULT_TOKEN: &str = "<bare result>";

/// Render `.length` / `?.length ?? 0` against a Dart field accessor.
///
/// Count-style assertions (`count_equals`, `count_min`, `min_length`, `max_length`)
/// operate on collection-typed fields. FRB v2 maps `Option<Vec<T>>` to `List<T>?`
/// (nullable) but `Vec<T>` to `List<T>` (non-null). Emitting `?.length ?? 0`
/// against a non-null receiver triggers `invalid_null_aware_operator`. Inspect
/// the IR via `FieldResolver::is_optional` and choose the safe form per field.
pub(super) fn dart_length_expr(field_accessor: &str, field: Option<&str>, field_resolver: &FieldResolver) -> String {
    let is_optional = field
        .map(|f| {
            let resolved = field_resolver.resolve(f);
            field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
        })
        .unwrap_or(false);
    if is_optional {
        format!("{field_accessor}?.length ?? 0")
    } else {
        format!("{field_accessor}.length")
    }
}

pub(super) fn dart_format_value(val: &serde_json::Value) -> String {
    match val {
        serde_json::Value::String(s) => format!("'{}'", escape_dart(s)),
        serde_json::Value::Bool(b) => b.to_string(),
        serde_json::Value::Number(n) => n.to_string(),
        serde_json::Value::Null => "null".to_string(),
        other => format!("'{}'", escape_dart(&other.to_string())),
    }
}

/// Render a single fixture assertion as a Dart `package:test` `expect(...)` call.
///
/// Field paths are converted per-segment to camelCase (FRB v2 convention) using
/// [`field_to_dart_accessor`].  All 24 fixture assertion types are handled.
///
/// Assertions on fixture fields that are not in the configured `result_fields` set
/// are emitted as a `// skipped:` comment instead — the Dart binding may model a
/// different result shape than the fixture asserts on (e.g. flat `ScrapeResult` vs.
/// nested `result.browser.*`), and emitting unresolvable getters would break the
/// whole file at compile time.
pub(super) fn render_assertion_dart(
    out: &mut String,
    assertion: &Assertion,
    result_var: &str,
    result_is_simple: bool,
    field_resolver: &FieldResolver,
) {
    // Skip assertions on fields that don't exist on the dart result type. This must run
    // BEFORE the array-traversal and standard accessor paths since both emit code that
    // references the field — an unknown field path produces an `isn't defined` error.
    if !result_is_simple && let Some(f) = assertion.field.as_deref() {
        // Pass the full, unsplit fixture path straight to `is_valid_for_result` — it
        // resolves aliases and extracts the first path segment itself. Alias keys are
        // the *whole* fixture path (e.g. `"hreflang[].lang"` -> `"metadata.hreflangs[].lang"`),
        // not just the head before `[].`, so pre-splitting off a head and validating that
        // (as this code used to) hands the resolver a substring no alias entry matches: an
        // aliased head then never resolves, and the assertion is wrongly skipped even though
        // the renamed field exists on the result type. Every other backend's assertions.rs
        // calls `is_valid_for_result(f)` on the raw full path for exactly this reason — do
        // the same here rather than re-deriving a head. ~keep
        if !f.is_empty() && !field_resolver.is_valid_for_result(f) {
            let _ = writeln!(
                out,
                "    // skipped: {}",
                FieldSkip::NotAvailableOnDartResultType.message(f)
            );
            return;
        }
    }

    if let Some(field) = assertion.field.as_deref()
        && !field.is_empty()
        && try_render_tagged_union_assertion(out, assertion, result_var, field_resolver, field)
    {
        return;
    }

    if let Some(field) = assertion.field.as_deref()
        && !field.is_empty()
        && field_resolver.tagged_union_split(field).is_some()
    {
        let _ = writeln!(
            out,
            "    // skipped: {}",
            FieldSkip::CrossesTaggedUnionBoundaryInDart.message(field)
        );
        return;
    }

    // Handle array traversal (e.g. "links[].link_type" → any() expression).
    if let Some(f) = assertion.field.as_deref()
        && let Some(dot) = f.find("[].")
    {
        // Apply the alias mapping to the full `xxx[].yyy` path first so renamed
        // sub-fields (e.g. `assets[].category` → `assets[].asset_category`) resolve
        // correctly. Split *after* resolving so both the array head and the element
        // path reflect any alias rewrites.
        let resolved_full = field_resolver.resolve(f);
        let (array_part, elem_part) = match resolved_full.find("[].") {
            Some(rdot) => (&resolved_full[..rdot], &resolved_full[rdot + 3..]),
            // Resolver mapped the path away from `[].` form — fall back to the original
            // split, since generated code expects the array/elem structure.
            None => (&f[..dot], &f[dot + 3..]),
        };
        // The split above consumes the first `[].` only, so a doubly-nested path leaves a
        // second wildcard in `elem_part`. Dart is the one backend where that is not even a
        // silent index-0 collapse: `field_to_dart_accessor` renders the bare bracket verbatim,
        // producing `e.links![].url`, which is not valid Dart. Refuse it here so the gap is a
        // recorded skip rather than a generated file that fails to analyze. ~keep
        if let Some(line) = nested_wildcard_skip_line("    ", "//", f, elem_part) {
            let _ = writeln!(out, "{line}");
            return;
        }
        let array_accessor = if array_part.is_empty() {
            result_var.to_string()
        } else {
            field_resolver.accessor(array_part, "dart", result_var)
        };
        let elem_accessor = field_to_dart_accessor(elem_part);
        // A data-carrying Rust enum (e.g. `StructureKind::Other(String)`) has no `wireValue`
        // extension in Dart — alef only emits `wireValue` for unit-only enums — so this
        // traversal has no wire-value accessor to fall back on the way the non-array `equals`
        // branch above does. flutter_rust_bridge/freezed's generated `toString()` for the
        // element's enum field yields the LOWER-CAMEL-CASE constructor call
        // (`'StructureKind.function()'`), which a fixture's PascalCase variant name
        // (`'Function'`) never case-sensitively matches. `.runtimeType.toString()` instead
        // yields alef's own generated concrete subclass name — `{EnumName}_{VariantName}` in
        // the variant's original (PascalCase) casing, e.g. `'StructureKind_Function'` — which
        // does. Restricted to enum-typed element fields only: a scalar field (e.g. a `String`
        // element) must keep comparing its actual `.toString()` content, not its Dart runtime
        // type name. ~keep
        let elem_is_enum = field_resolver.is_enum(f) || field_resolver.is_enum(resolved_full);
        let elem_to_string = if elem_is_enum {
            format!("e.{elem_accessor}.runtimeType.toString()")
        } else {
            format!("e.{elem_accessor}.toString()")
        };
        match assertion.assertion_type.as_str() {
            "contains" => {
                if let Some(expected) = &assertion.value {
                    let dart_val = dart_format_value(expected);
                    let _ = writeln!(
                        out,
                        "    expect({array_accessor}.any((e) => {elem_to_string}.contains({dart_val})), isTrue);"
                    );
                }
            }
            "contains_all" => {
                if let Some(values) = &assertion.values {
                    for val in values {
                        let dart_val = dart_format_value(val);
                        let _ = writeln!(
                            out,
                            "    expect({array_accessor}.any((e) => {elem_to_string}.contains({dart_val})), isTrue);"
                        );
                    }
                }
            }
            "not_contains" => {
                if let Some(expected) = &assertion.value {
                    let dart_val = dart_format_value(expected);
                    let _ = writeln!(
                        out,
                        "    expect({array_accessor}.any((e) => {elem_to_string}.contains({dart_val})), isFalse);"
                    );
                } else if let Some(values) = &assertion.values {
                    for val in values {
                        let dart_val = dart_format_value(val);
                        let _ = writeln!(
                            out,
                            "    expect({array_accessor}.any((e) => {elem_to_string}.contains({dart_val})), isFalse);"
                        );
                    }
                }
            }
            "not_empty" => {
                let _ = writeln!(
                    out,
                    "    expect({array_accessor}.any((e) => e.{elem_accessor}.toString().isNotEmpty), isTrue);"
                );
            }
            other => {
                let _ = writeln!(
                    out,
                    "    // skipped: unsupported traversal assertion '{other}' on '{f}'"
                );
            }
        }
        return;
    }

    // A payload-carrying union has no `.wireValue` extension (`flat_wire_enums` emits one only
    // for an all-fieldless-variants enum) and no honest fallback: freezed's `toString()` on the
    // generated sealed class is a diagnostic rendering, not the serde wire value, so comparing it
    // to the fixture literal asserts the wrong string. Refuse instead. Placed AFTER the `[].`
    // traversal above, which has its own answer for a union-typed element (`.runtimeType`). ~keep
    if let Some(line) = payload_union_skip_line(
        "    ",
        "//",
        field_resolver,
        assertion.field.as_deref(),
        UnionLoweringTarget::Dart,
    ) {
        let _ = writeln!(out, "{line}");
        return;
    }

    let field_accessor = if result_is_simple {
        // Whole-result assertion path: the dart return is a scalar (e.g. a
        // `Uint8List` for speech/file_content), so any `field` on the
        // assertion resolves to the whole value rather than a sub-accessor.
        result_var.to_string()
    } else {
        match assertion.field.as_deref() {
            // Use the shared accessor builder (`FieldResolver::accessor`) — it applies the
            // alias mapping (e.g. `robots.is_allowed` → `is_allowed`), expands array
            // segments to `[0]` lookups, and injects `!` after optional intermediates so
            // chained access compiles under sound null safety.
            Some(f) if !f.is_empty() => field_resolver.accessor(f, "dart", result_var),
            _ => result_var.to_string(),
        }
    };

    let format_value = |val: &serde_json::Value| -> String { dart_format_value(val) };

    match assertion.assertion_type.as_str() {
        "equals" | "field_equals" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                // Check if this field is an enum field. Enum fields are compared against the
                // binding's `.wireValue` getter (see `gen_bindings::enum_wire_values`), which
                // returns the exact serde wire value for the variant.
                // `field_resolver.is_enum` consults the hand-maintained `fields_enum`/
                // `enum_fields` config first and only then the IR-derived classification
                // (`with_ir_enum_map`), so an explicit config entry still wins — this only
                // rescues fields a consumer's `alef.toml` never mentions. A config-only check
                // used to answer `false` for those, SILENTLY skipping the `.wireValue` accessor
                // rather than failing to compile: `expect(result.kind.toString(), equals('key_value'))`
                // compares the enum's Dart `toString()` (its variant name) against the fixture's
                // serde wire value, so the test passes or fails on the wrong string. ~keep
                //
                // A payload-carrying union never reaches here: `payload_union_skip_line` above
                // refused it, because it has no `.wireValue` AND no honest fallback. ~keep
                let is_enum_field = assertion
                    .field
                    .as_deref()
                    .filter(|f| !f.is_empty())
                    .is_some_and(|f| field_resolver.is_enum(f));

                // Check if this field is a display-as-text type (e.g. AssistantContent).
                let is_display_as_text = assertion
                    .field
                    .as_deref()
                    .map(|f| {
                        let resolved = field_resolver.resolve(f);
                        field_resolver.is_display_as_text(f) || field_resolver.is_display_as_text(resolved)
                    })
                    .unwrap_or(false);

                if expected.is_string() {
                    if is_enum_field {
                        // For enum fields, assert the fixture's serde wire literal VERBATIM
                        // against the binding's `.wireValue` getter -- not a value rebuilt from
                        // the idiomatic Dart member name, which is a separate naming surface
                        // (`centralized-naming`) and cannot losslessly round-trip back to the
                        // wire value.
                        let is_optional = assertion
                            .field
                            .as_deref()
                            .map(|f| {
                                let resolved = field_resolver.resolve(f);
                                field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
                            })
                            .unwrap_or(false);
                        let wire_accessor = if is_optional {
                            format!("{field_accessor}?.wireValue")
                        } else {
                            format!("{field_accessor}.wireValue")
                        };
                        let _ = writeln!(out, "    expect({wire_accessor}, equals({dart_val}));");
                    } else if is_display_as_text {
                        // For display-as-text types (e.g. AssistantContent), use .text() accessor
                        // to extract the plain-text representation instead of calling .toString()
                        // which would return the class name.
                        // Check if the field is optional; if so, use safe navigation (?.) and provide fallback.
                        let is_optional = assertion
                            .field
                            .as_deref()
                            .map(|f| {
                                let resolved = field_resolver.resolve(f);
                                field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
                            })
                            .unwrap_or(false);

                        if is_optional {
                            let _ = writeln!(
                                out,
                                "    expect(({field_accessor}?.text() ?? ''), equals({dart_val}.toString()));"
                            );
                        } else {
                            let _ = writeln!(
                                out,
                                "    expect({field_accessor}.text(), equals({dart_val}.toString()));"
                            );
                        }
                    } else {
                        // When result_is_simple is true and the field_accessor is nullable (e.g. String?),
                        // use null-coalescing operator (?? '') to handle null gracefully.
                        let safe_accessor = if result_is_simple && assertion.field.is_none() {
                            format!("({field_accessor} ?? '').toString()")
                        } else {
                            format!("{field_accessor}.toString()")
                        };
                        let _ = writeln!(out, "    expect({safe_accessor}, equals({dart_val}.toString()));");
                    }
                } else {
                    let _ = writeln!(out, "    expect({field_accessor}, equals({dart_val}));");
                }
            } else {
                let _ = writeln!(
                    out,
                    "    // skipped: '{}' assertion missing value",
                    assertion.assertion_type
                );
            }
        }
        "not_equals" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                // Check if this field is an enum field. See the `equals`/`field_equals` arm
                // above for why this must consult the IR, not only the config. ~keep
                let is_enum_field = assertion
                    .field
                    .as_deref()
                    .filter(|f| !f.is_empty())
                    .is_some_and(|f| field_resolver.is_enum(f));

                // Check if this field is a display-as-text type.
                let is_display_as_text = assertion
                    .field
                    .as_deref()
                    .map(|f| {
                        let resolved = field_resolver.resolve(f);
                        field_resolver.is_display_as_text(f) || field_resolver.is_display_as_text(resolved)
                    })
                    .unwrap_or(false);

                if expected.is_string() {
                    if is_enum_field {
                        // See the `equals`/`field_equals` arm above: compare the fixture's wire
                        // literal VERBATIM against `.wireValue`, not a `.toString()` rebuild.
                        let is_optional = assertion
                            .field
                            .as_deref()
                            .map(|f| {
                                let resolved = field_resolver.resolve(f);
                                field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
                            })
                            .unwrap_or(false);
                        let wire_accessor = if is_optional {
                            format!("{field_accessor}?.wireValue")
                        } else {
                            format!("{field_accessor}.wireValue")
                        };
                        let _ = writeln!(out, "    expect({wire_accessor}, isNot(equals({dart_val})));");
                    } else if is_display_as_text {
                        // For display-as-text types, use .text() accessor.
                        // Check if the field is optional; if so, use safe navigation (?.) and provide fallback.
                        let is_optional = assertion
                            .field
                            .as_deref()
                            .map(|f| {
                                let resolved = field_resolver.resolve(f);
                                field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
                            })
                            .unwrap_or(false);

                        if is_optional {
                            let _ = writeln!(
                                out,
                                "    expect(({field_accessor}?.text() ?? '').trim(), isNot(equals({dart_val}.toString().trim())));"
                            );
                        } else {
                            let _ = writeln!(
                                out,
                                "    expect({field_accessor}.text().trim(), isNot(equals({dart_val}.toString().trim())));"
                            );
                        }
                    } else {
                        // When result_is_simple is true and the field_accessor is nullable (e.g. String?),
                        // use null-coalescing operator (?? '') to handle null gracefully.
                        let safe_accessor = if result_is_simple && assertion.field.is_none() {
                            format!("({field_accessor} ?? '').toString().trim()")
                        } else {
                            format!("{field_accessor}.toString().trim()")
                        };
                        let _ = writeln!(
                            out,
                            "    expect({safe_accessor}, isNot(equals({dart_val}.toString().trim())));"
                        );
                    }
                } else {
                    let _ = writeln!(out, "    expect({field_accessor}, isNot(equals({dart_val})));");
                }
            }
        }
        "contains" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                // Try the "stringy aggregator" path first: when the field is a list of DTOs
                // with multiple text-bearing accessors (e.g. List<ImportInfo> with
                // source/items/alias), emit code that walks every accessor and does
                // substring matching. This avoids the brittle "primary accessor" guess.
                let aggregator = dart_stringy_aggregator_contains_assert(
                    assertion.field.as_deref(),
                    result_var,
                    field_resolver,
                    &dart_val,
                );
                if let Some(line) = aggregator {
                    let _ = writeln!(out, "{line}");
                } else {
                    let _ = writeln!(out, "    expect({field_accessor}, contains({dart_val}));");
                }
            } else {
                let _ = writeln!(out, "    // skipped: 'contains' assertion missing value");
            }
        }
        "contains_all" => {
            if let Some(values) = &assertion.values {
                for val in values {
                    let dart_val = format_value(val);
                    let _ = writeln!(out, "    expect({field_accessor}, contains({dart_val}));");
                }
            }
        }
        "contains_any" => {
            if let Some(values) = &assertion.values {
                let checks: Vec<String> = values
                    .iter()
                    .map(|v| {
                        let dart_val = format_value(v);
                        format!("{field_accessor}.contains({dart_val})")
                    })
                    .collect();
                let joined = checks.join(" || ");
                let _ = writeln!(out, "    expect({joined}, isTrue);");
            }
        }
        "not_contains" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                let _ = writeln!(out, "    expect({field_accessor}, isNot(contains({dart_val})));");
            } else if let Some(values) = &assertion.values {
                for val in values {
                    let dart_val = format_value(val);
                    let _ = writeln!(out, "    expect({field_accessor}, isNot(contains({dart_val})));");
                }
            }
        }
        "not_empty" => {
            // `isNotEmpty` only applies to types with a `.isEmpty` getter (collections,
            // strings, maps). For struct-shaped fields (e.g. `document: DocumentStructure`)
            // we instead assert the value is non-null — those types have no notion of
            // "empty" and the fixture intent is "the field is present".
            // `is_array` alone misses a collection field whose entries are only tracked via
            // their element paths in `fields_array` (e.g. `children[0]` for a recursive
            // `Option<Vec<DataNode>> Children`, never a bare `children` entry) —
            // `is_collection_root` catches that shape from the IR instead of config alone.
            // Checked against both the raw and resolved path, matching csharp/kotlin/swift's
            // identical `field_is_collection` guard. ~keep
            let is_collection = assertion.field.as_deref().is_some_and(|f| {
                let resolved = field_resolver.resolve(f);
                field_resolver.is_array(f)
                    || field_resolver.is_array(resolved)
                    || field_resolver.is_collection_root(f)
                    || field_resolver.is_collection_root(resolved)
            });
            if is_collection {
                let _ = writeln!(out, "    expect({field_accessor}, isNotEmpty);");
            } else {
                let is_optional = assertion.field.as_deref().is_some_and(|field| {
                    let resolved = field_resolver.resolve(field);
                    field_resolver.is_optional(field) || field_resolver.is_optional(resolved)
                });
                let null_aware = if is_optional { "?" } else { "" };
                let _ = writeln!(out, "    expect({field_accessor}{null_aware}.toString(), isNotEmpty);");
            }
        }
        "is_empty" => {
            // FRB models `Option<String>` / `Option<Vec<T>>` as nullable in Dart. The `isEmpty`
            // matcher throws `NoSuchMethodError` on `null`. Accept `null` as semantically
            // empty by combining `isNull` with `isEmpty` via `anyOf`.
            //
            // `isEmpty`/`anyOf(isNull, isEmpty)` only applies to types with an `.isEmpty`
            // getter (collections, strings, maps) -- the same constraint `not_empty` above
            // branches on. A struct- or scalar-shaped field (e.g. `document:
            // DocumentStructure`) has no `.isEmpty` getter and throws `NoSuchMethodError` if
            // this arm calls it directly. Stringify first, the same way `not_empty`'s
            // non-collection branch does, and fall back to `''` for `null` so the "null counts
            // as empty" intent above still holds.
            // `is_array` alone misses a collection field whose entries are only tracked via
            // their element paths in `fields_array` (e.g. `children[0]` for a recursive
            // `Option<Vec<DataNode>> Children`, never a bare `children` entry) —
            // `is_collection_root` catches that shape from the IR instead of config alone.
            // Checked against both the raw and resolved path, matching csharp/kotlin/swift's
            // identical `field_is_collection` guard. ~keep
            let is_collection = assertion.field.as_deref().is_some_and(|f| {
                let resolved = field_resolver.resolve(f);
                field_resolver.is_array(f)
                    || field_resolver.is_array(resolved)
                    || field_resolver.is_collection_root(f)
                    || field_resolver.is_collection_root(resolved)
            });
            if is_collection {
                let _ = writeln!(out, "    expect({field_accessor}, anyOf(isNull, isEmpty));");
            } else {
                let _ = writeln!(out, "    expect(({field_accessor}?.toString() ?? ''), isEmpty);");
            }
        }
        "starts_with" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                let _ = writeln!(out, "    expect({field_accessor}, startsWith({dart_val}));");
            }
        }
        "ends_with" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                let _ = writeln!(out, "    expect({field_accessor}, endsWith({dart_val}));");
            }
        }
        "min_length" => {
            if let Some(val) = &assertion.value
                && let Some(n) = val.as_u64()
            {
                let length_expr = dart_length_expr(&field_accessor, assertion.field.as_deref(), field_resolver);
                let _ = writeln!(out, "    expect({length_expr}, greaterThanOrEqualTo({n}));");
            }
        }
        "max_length" => {
            if let Some(val) = &assertion.value
                && let Some(n) = val.as_u64()
            {
                let length_expr = dart_length_expr(&field_accessor, assertion.field.as_deref(), field_resolver);
                let _ = writeln!(out, "    expect({length_expr}, lessThanOrEqualTo({n}));");
            }
        }
        "count_equals" => {
            if let Some(val) = &assertion.value
                && let Some(n) = val.as_u64()
            {
                let length_expr = dart_length_expr(&field_accessor, assertion.field.as_deref(), field_resolver);
                let _ = writeln!(out, "    expect({length_expr}, equals({n}));");
            }
        }
        "count_min" => {
            if let Some(val) = &assertion.value
                && let Some(n) = val.as_u64()
            {
                let length_expr = dart_length_expr(&field_accessor, assertion.field.as_deref(), field_resolver);
                let _ = writeln!(out, "    expect({length_expr}, greaterThanOrEqualTo({n}));");
            }
        }
        "matches_regex" => {
            if let Some(expected) = &assertion.value {
                let dart_val = format_value(expected);
                let _ = writeln!(out, "    expect({field_accessor}, matches(RegExp({dart_val})));");
            }
        }
        "is_true" => {
            let is_optional = assertion.field.as_ref().is_some_and(|f| {
                let resolved = field_resolver.resolve(f);
                field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
            });
            if is_optional {
                // `T?`: "is_true" means "present" -- `isTrue` requires the value to be the
                // literal `bool` `true`, which does not type-check for e.g. `DataNode?` and
                // is simply always false for any other present, non-bool value. `isNotNull`
                // is the interpretation that holds for any T, matching the Rust `.is_some()`
                // convention for this assertion type. ~keep
                let _ = writeln!(out, "    expect({field_accessor}, isNotNull);");
            } else {
                let _ = writeln!(out, "    expect({field_accessor}, isTrue);");
            }
        }
        "is_false" => {
            let is_optional = assertion.field.as_ref().is_some_and(|f| {
                let resolved = field_resolver.resolve(f);
                field_resolver.is_optional(f) || field_resolver.is_optional(resolved)
            });
            if is_optional {
                let _ = writeln!(out, "    expect({field_accessor}, isNull);");
            } else {
                let _ = writeln!(out, "    expect({field_accessor}, isFalse);");
            }
        }
        "greater_than" => {
            if let Some(val) = &assertion.value {
                let dart_val = format_value(val);
                let _ = writeln!(out, "    expect({field_accessor}, greaterThan({dart_val}));");
            }
        }
        "less_than" => {
            if let Some(val) = &assertion.value {
                let dart_val = format_value(val);
                let _ = writeln!(out, "    expect({field_accessor}, lessThan({dart_val}));");
            }
        }
        "greater_than_or_equal" => {
            if let Some(val) = &assertion.value {
                let dart_val = format_value(val);
                let _ = writeln!(out, "    expect({field_accessor}, greaterThanOrEqualTo({dart_val}));");
            }
        }
        "less_than_or_equal" => {
            if let Some(val) = &assertion.value {
                let dart_val = format_value(val);
                let _ = writeln!(out, "    expect({field_accessor}, lessThanOrEqualTo({dart_val}));");
            }
        }
        "not_null" => {
            let _ = writeln!(out, "    expect({field_accessor}, isNotNull);");
        }
        "not_error" => {
            // The `await` already guarantees no thrown error reaches this point — if
            // the call throws, the test fails before reaching here. Don't emit
            // `expect(result, isNotNull)` here unconditionally: for void-returning
            // trait-bridge fns (clear_*) Dart rejects `expect(<void>, ...)` with
            // "expression has type 'void' and can't be used". `test_case.rs`'s
            // caller adds a real `expect(result, isNotNull)` fallback (mirroring
            // the streaming path's existing idiom) when this is the fixture's only
            // assertion and the call is non-void, so the body isn't left vacuous.
        }
        "error" => {
            // ~keep Handled at the test method level, via `dart_error_matcher` in
            // `test_case.rs` (throwsA(anything) or a declared-value predicate matcher).
        }
        "method_result" => {
            if let Some(method) = &assertion.method {
                let dart_method = method.to_lower_camel_case();
                let check = assertion.check.as_deref().unwrap_or("not_null");
                let method_call = format!("{field_accessor}.{dart_method}()");
                match check {
                    "equals" => {
                        if let Some(expected) = &assertion.value {
                            let dart_val = format_value(expected);
                            let _ = writeln!(out, "    expect({method_call}, equals({dart_val}));");
                        }
                    }
                    "is_true" => {
                        let _ = writeln!(out, "    expect({method_call}, isTrue);");
                    }
                    "is_false" => {
                        let _ = writeln!(out, "    expect({method_call}, isFalse);");
                    }
                    "greater_than_or_equal" => {
                        if let Some(val) = &assertion.value {
                            let dart_val = format_value(val);
                            let _ = writeln!(out, "    expect({method_call}, greaterThanOrEqualTo({dart_val}));");
                        }
                    }
                    "count_min" => {
                        if let Some(val) = &assertion.value
                            && let Some(n) = val.as_u64()
                        {
                            let _ = writeln!(out, "    expect({method_call}.length, greaterThanOrEqualTo({n}));");
                        }
                    }
                    _ => {
                        let _ = writeln!(out, "    expect({method_call}, isNotNull);");
                    }
                }
            }
        }
        other => {
            let _ = writeln!(out, "    // skipped: unknown assertion type '{other}'");
        }
    }
}

/// Render a single fixture assertion for a streaming result.
///
/// `result_var` is the `List<T>` collected via `.toList()` on the stream.
/// Supports:
/// - `not_error`: `expect(result, isNotNull)` (a thrown error would already fail
///   the test; the explicit expect keeps the test body non-empty).
/// - `count_min` with `field = "chunks"`: assert `result_var.length >= value`.
/// - `equals` with `field = "stream_content"`: concatenate `delta.content` and compare.
///
/// Other assertion types are emitted as comments.
pub(super) fn render_streaming_assertion_dart(out: &mut String, assertion: &Assertion, result_var: &str) {
    match assertion.assertion_type.as_str() {
        "not_error" => {
            // `.toList()` would have thrown to fail the test on error; emit an
            // explicit `expect` so the test body isn't empty and the collected
            // stream variable is consumed.
            let _ = writeln!(out, "    expect({result_var}, isNotNull);");
        }
        // ~keep Both guarded arms below used to emit nothing when the fixture's value was not the
        // JSON kind the renderer narrows to, so a `count_min` whose value was a string (or a
        // `stream_content` `equals` against a number) vanished with no line for any funnel to see.
        "count_min" if assertion.field.as_deref() == Some("chunks") => {
            if let Some(serde_json::Value::Number(n)) = &assertion.value {
                let _ = writeln!(out, "    expect({result_var}.length, greaterThanOrEqualTo({n}));");
            } else {
                let _ = writeln!(
                    out,
                    "{}",
                    streaming_assertion_value_skip_line("    ", "//", "chunks", &assertion.assertion_type)
                );
            }
        }
        "equals" if assertion.field.as_deref() == Some("stream_content") => {
            if let Some(serde_json::Value::String(expected)) = &assertion.value {
                let escaped = escape_dart(expected);
                let _ = writeln!(
                    out,
                    "    final _content = {result_var}.map((c) => c.choices.firstOrNull?.delta.content ?? '').join();"
                );
                let _ = writeln!(out, "    expect(_content, equals('{escaped}'));");
            } else {
                let _ = writeln!(
                    out,
                    "{}",
                    streaming_assertion_value_skip_line("    ", "//", "stream_content", &assertion.assertion_type)
                );
            }
        }
        // ~keep Was `// skipped streaming assertion: '<type>'`, which matched no registered shape
        // — the quoted token sat after a colon rather than after any variant's `before` text — so
        // neither funnel could count it however loudly it read.
        _ => {
            let _ = writeln!(
                out,
                "{}",
                streaming_assertion_type_skip_line(
                    "    ",
                    "//",
                    assertion.field.as_deref().unwrap_or(BARE_RESULT_TOKEN),
                    &assertion.assertion_type
                )
            );
        }
    }
}

/// Convert a dot-separated fixture field path to a Dart accessor expression.
///
/// Each segment is converted to camelCase (FRB v2 convention); array-index brackets
/// (e.g. `choices[0]`) and map-key brackets (e.g. `tags[name]`) are preserved.
/// This replaces the former single-pass `underscore_camel_case` call which incorrectly
/// treated the entire path string as one identifier.
///
/// Examples:
/// - `"choices"` → `"choices"`
/// - `"choices[0].message.content"` → `"choices[0].message.content"`
/// - `"metadata.document_title"` → `"metadata.documentTitle"`
/// - `"model_id"` → `"modelId"`
pub(super) fn field_to_dart_accessor(path: &str) -> String {
    let mut result = String::with_capacity(path.len());
    for (i, segment) in path.split('.').enumerate() {
        if i > 0 {
            result.push('.');
        }
        // Separate a trailing `[...]` bracket from the field name so we only
        // camelCase the identifier part, not the bracket content. The owning
        // collection may be `List<T>?` when the underlying Rust field is
        // `Option<Vec<T>>`; force-unwrap with `!` so the `[N]` lookup and any
        // subsequent member access compile under sound null safety.
        if let Some(bracket_pos) = segment.find('[') {
            let name = &segment[..bracket_pos];
            let bracket = &segment[bracket_pos..];
            result.push_str(&name.to_lower_camel_case());
            result.push('!');
            result.push_str(bracket);
        } else {
            result.push_str(&segment.to_lower_camel_case());
        }
    }
    result
}

/// Emit a `expect(array.where(...).any(...), isTrue)` line that aggregates
/// every accessor on the element type of a `List<T>` field, mirroring
/// python's `_alef_e2e_item_texts` helper.
///
/// Since Dart e2e codegen doesn't currently carry type information for per-type
/// field classification, this fallback always tries to aggregate common text-bearing
/// accessors (kind, name, source, items, alias, and similar snake_case names) on any
/// element type. This is lenient and works well with opaque DTOs from FRB binding
/// generation where we can't statically determine the exact field structure.
///
/// Returns `None` when:
///   - `field` is missing or the field doesn't look like an array field
///
/// When matched, emits code that tries to gather text from a set of known
/// accessor names into a `[String]` and substring-matches the expected value
/// against every entry. The matcher is lenient so that fixtures asserting `"os"`
/// against the `imports` field succeed regardless of which accessor surfaces
/// the value (`ImportInfo.source`, `ImportInfo.items`, etc.).
///
/// First tries the "stringy aggregator" path: when the array element is an
/// opaque DTO with several text-bearing accessors, emit a `where(...)`
/// closure that walks every accessor and does substring matching. Falls back
/// to the catch-all path if no stringy fields are recorded for the element type.
pub(super) fn dart_stringy_aggregator_contains_assert(
    field: Option<&str>,
    result_var: &str,
    field_resolver: &crate::e2e::field_access::FieldResolver,
    dart_val: &str,
) -> Option<String> {
    use crate::e2e::field_access::StringyFieldKind;
    let field = field?;
    let resolved = field_resolver.resolve(field);

    // Only handle simple top-level array fields (no nested chains).
    if resolved.contains('.') || resolved.contains('[') {
        return None;
    }

    // Check if this is a known array field. If not, we can't tell if it's a
    // list of DTOs so bail out and let the scalar list path handle it.
    if !field_resolver.is_array(field) && !field_resolver.is_array(resolved) {
        return None;
    }

    let array_accessor = field_resolver.accessor(field, "dart", result_var);

    // Try the stringy aggregator path: if the element type has multiple
    // text-bearing accessors, emit a proper aggregator instead of a catch-all.
    let root_type = field_resolver.dart_root_type().cloned();
    if let Some(elem_type) = field_resolver.dart_advance(root_type.as_deref(), resolved)
        && let Some(stringy) = field_resolver.dart_stringy_fields(&elem_type)
    {
        // Only emit the aggregator if the element type has 2+ stringy fields.
        // Single-field types are better served by the simpler single-accessor path.
        if stringy.len() >= 2 {
            // flutter_rust_bridge renders struct DTOs as plain Dart classes
            // with `final` fields, so accessors are property reads (no
            // parens). Dart is statically typed — calling `item.field()` on
            // a non-callable field, or naming a field the type lacks, is a
            // compile error, not a runtime miss.
            let mut texts_lines: Vec<String> = Vec::new();
            for sf in stringy {
                let call = sf.name.to_lower_camel_case();
                match sf.kind {
                    StringyFieldKind::Plain => {
                        texts_lines.push(format!("            texts.add(item.{call}.toString());"));
                    }
                    StringyFieldKind::Optional => {
                        texts_lines.push(format!(
                                "            final v_{call} = item.{call};\n            if (v_{call} != null) texts.add(v_{call}.toString());"
                            ));
                    }
                    StringyFieldKind::Vec => {
                        texts_lines.push(format!(
                            "            texts.addAll(item.{call}.map((e) => e.toString()));"
                        ));
                    }
                }
            }
            let texts_block = texts_lines.join("\n");
            // Case-insensitive substring match: enum/sealed-class fields
            // stringify to `EnumName.variant()` (lowerCamelCase variant),
            // while fixture node-type values are PascalCase (`Function`).
            return Some(format!(
                "    expect({array_accessor}.where((item) {{\n            final texts = <String>[];\n{texts_block}\n            return texts.any((t) => t.toLowerCase().contains(({dart_val}).toString().toLowerCase()));\n          }}).isEmpty, isFalse);"
            ));
        }
    }

    // Fallback: the element type's fields could not be resolved from the IR
    // (unknown root type, or fewer than two recorded stringy fields). Dart is
    // statically typed, so probing arbitrary accessor names cannot compile —
    // emit a lenient whole-object stringification match that always compiles.
    Some(format!(
        "    expect({array_accessor}.where((item) => item.toString().toLowerCase().contains(({dart_val}).toString().toLowerCase())).isEmpty, isFalse);"
    ))
}

#[cfg(test)]
mod tests;