alef-e2e 0.3.0

//! Ruby e2e test generator using RSpec.
//!
//! Generates `e2e/ruby/Gemfile` and `spec/{category}_spec.rb` files from
//! JSON fixtures, driven entirely by `E2eConfig` and `CallConfig`.

use crate::config::E2eConfig;
use crate::escape::{ruby_string_literal, sanitize_filename, sanitize_ident};
use crate::field_access::FieldResolver;
use crate::fixture::{Assertion, Fixture, FixtureGroup};
use alef_core::backend::GeneratedFile;
use alef_core::config::AlefConfig;
use anyhow::Result;
use heck::ToSnakeCase;
use std::collections::HashMap;
use std::fmt::Write as FmtWrite;
use std::path::PathBuf;

use super::E2eCodegen;

/// Ruby e2e code generator.
pub struct RubyCodegen;

impl E2eCodegen for RubyCodegen {
    fn generate(
        &self,
        groups: &[FixtureGroup],
        e2e_config: &E2eConfig,
        alef_config: &AlefConfig,
    ) -> Result<Vec<GeneratedFile>> {
        let lang = self.language_name();
        let output_base = PathBuf::from(&e2e_config.output).join(lang);

        let mut files = Vec::new();

        // Resolve call config with overrides.
        let call = &e2e_config.call;
        let overrides = call.overrides.get(lang);
        let module_path = overrides
            .and_then(|o| o.module.as_ref())
            .cloned()
            .unwrap_or_else(|| call.module.clone());
        let function_name = overrides
            .and_then(|o| o.function.as_ref())
            .cloned()
            .unwrap_or_else(|| call.function.clone());
        let class_name = overrides.and_then(|o| o.class.as_ref()).cloned();
        let options_type = overrides.and_then(|o| o.options_type.clone());
        let empty_enum_fields = HashMap::new();
        let enum_fields = overrides.map(|o| &o.enum_fields).unwrap_or(&empty_enum_fields);
        let result_is_simple = overrides.is_some_and(|o| o.result_is_simple);
        let result_var = &call.result_var;

        // Resolve package config.
        let ruby_pkg = e2e_config.packages.get("ruby");
        let gem_name = ruby_pkg
            .and_then(|p| p.name.as_ref())
            .cloned()
            .unwrap_or_else(|| alef_config.crate_config.name.replace('-', "_"));
        let gem_path = ruby_pkg
            .and_then(|p| p.path.as_ref())
            .cloned()
            .unwrap_or_else(|| "../../packages/ruby".to_string());

        // Generate Gemfile.
        files.push(GeneratedFile {
            path: output_base.join("Gemfile"),
            content: render_gemfile(&gem_name, &gem_path),
            generated_header: false,
        });

        // Generate .rubocop.yaml for linting generated specs.
        files.push(GeneratedFile {
            path: output_base.join(".rubocop.yaml"),
            content: render_rubocop_yaml(),
            generated_header: false,
        });

        // Generate spec files per category.
        let spec_base = output_base.join("spec");

        for group in groups {
            let active: Vec<&Fixture> = group
                .fixtures
                .iter()
                .filter(|f| f.skip.as_ref().is_none_or(|s| !s.should_skip(lang)))
                .collect();

            if active.is_empty() {
                continue;
            }

            let field_resolver_pre = FieldResolver::new(
                &e2e_config.fields,
                &e2e_config.fields_optional,
                &e2e_config.result_fields,
                &e2e_config.fields_array,
            );
            // Skip the entire file if no fixture in this category produces output.
            let has_any_output = active.iter().any(|f| {
                let expects_error = f.assertions.iter().any(|a| a.assertion_type == "error");
                expects_error || has_usable_assertion(f, &field_resolver_pre, result_is_simple)
            });
            if !has_any_output {
                continue;
            }

            let filename = format!("{}_spec.rb", sanitize_filename(&group.category));
            let field_resolver = FieldResolver::new(
                &e2e_config.fields,
                &e2e_config.fields_optional,
                &e2e_config.result_fields,
                &e2e_config.fields_array,
            );
            let content = render_spec_file(
                &group.category,
                &active,
                &module_path,
                &function_name,
                class_name.as_deref(),
                result_var,
                &gem_name,
                &e2e_config.call.args,
                &field_resolver,
                options_type.as_deref(),
                enum_fields,
                result_is_simple,
            );
            files.push(GeneratedFile {
                path: spec_base.join(filename),
                content,
                generated_header: true,
            });
        }

        Ok(files)
    }

    fn language_name(&self) -> &'static str {
        "ruby"
    }
}

// ---------------------------------------------------------------------------
// Rendering
// ---------------------------------------------------------------------------

fn render_gemfile(gem_name: &str, gem_path: &str) -> String {
    format!(
        "# frozen_string_literal: true\n\
         \n\
         source 'https://rubygems.org'\n\
         \n\
         gem '{gem_name}', path: '{gem_path}'\n\
         gem 'rspec', '~> 3.13'\n\
         gem 'rubocop', '~> 1.86'\n\
         gem 'rubocop-rspec', '~> 3.9'\n"
    )
}

fn render_rubocop_yaml() -> String {
    r#"# Generated by alef e2e — do not edit.
AllCops:
  NewCops: enable
  TargetRubyVersion: 3.2
  SuggestExtensions: false

plugins:
  - rubocop-rspec

# --- Justified suppressions for generated test code ---

# Generated tests are verbose by nature (setup + multiple assertions).
Metrics/BlockLength:
  Enabled: false
Metrics/MethodLength:
  Enabled: false
Layout/LineLength:
  Enabled: false

# Generated tests use multiple assertions per example for thorough verification.
RSpec/MultipleExpectations:
  Enabled: false
RSpec/ExampleLength:
  Enabled: false

# Generated tests describe categories as strings, not classes.
RSpec/DescribeClass:
  Enabled: false

# Fixture-driven tests may produce identical assertion bodies for different inputs.
RSpec/RepeatedExample:
  Enabled: false

# Error-handling tests use bare raise_error (exception type not known at generation time).
RSpec/UnspecifiedException:
  Enabled: false
"#
    .to_string()
}

#[allow(clippy::too_many_arguments)]
fn render_spec_file(
    category: &str,
    fixtures: &[&Fixture],
    module_path: &str,
    function_name: &str,
    class_name: Option<&str>,
    result_var: &str,
    gem_name: &str,
    args: &[crate::config::ArgMapping],
    field_resolver: &FieldResolver,
    options_type: Option<&str>,
    enum_fields: &HashMap<String, String>,
    result_is_simple: bool,
) -> String {
    let mut out = String::new();
    let _ = writeln!(out, "# This file is auto-generated by alef. DO NOT EDIT.");
    let _ = writeln!(out, "# frozen_string_literal: true");
    let _ = writeln!(out);

    // Require the gem (single quotes).
    let require_name = if module_path.is_empty() { gem_name } else { module_path };
    let _ = writeln!(out, "require '{}'", require_name.replace('-', "_"));
    let _ = writeln!(out, "require 'json'");
    let _ = writeln!(out);

    // Build the Ruby module/class qualifier for calls.
    let call_receiver = class_name
        .map(|s| s.to_string())
        .unwrap_or_else(|| ruby_module_name(module_path));

    let _ = writeln!(out, "RSpec.describe '{}' do", category);

    let mut first = true;
    for fixture in fixtures {
        // Skip examples that have zero usable assertions (no executable expect() calls).
        // This prevents Lint/UselessAssignment, RSpec/NoExpectationExample,
        // and RSpec/RepeatedExample.
        let expects_error = fixture.assertions.iter().any(|a| a.assertion_type == "error");
        if !expects_error && !has_usable_assertion(fixture, field_resolver, result_is_simple) {
            continue;
        }

        if !first {
            let _ = writeln!(out);
        }
        first = false;

        render_example(
            &mut out,
            fixture,
            function_name,
            &call_receiver,
            result_var,
            args,
            field_resolver,
            options_type,
            enum_fields,
            result_is_simple,
        );
    }

    let _ = writeln!(out, "end");
    out
}

/// Check if a fixture has at least one assertion that will produce an executable
/// expect() call (not just a skip comment).
fn has_usable_assertion(fixture: &Fixture, field_resolver: &FieldResolver, result_is_simple: bool) -> bool {
    fixture.assertions.iter().any(|a| {
        // not_error is implicit (call succeeding), error is handled separately.
        if a.assertion_type == "not_error" || a.assertion_type == "error" {
            return false;
        }
        // Check field validity.
        if let Some(f) = &a.field {
            if !f.is_empty() && !field_resolver.is_valid_for_result(f) {
                return false;
            }
            // When result_is_simple, skip non-content fields.
            if result_is_simple {
                let f_lower = f.to_lowercase();
                if !f.is_empty()
                    && f_lower != "content"
                    && (f_lower.starts_with("metadata")
                        || f_lower.starts_with("document")
                        || f_lower.starts_with("structure"))
                {
                    return false;
                }
            }
        }
        true
    })
}

#[allow(clippy::too_many_arguments)]
fn render_example(
    out: &mut String,
    fixture: &Fixture,
    function_name: &str,
    call_receiver: &str,
    result_var: &str,
    args: &[crate::config::ArgMapping],
    field_resolver: &FieldResolver,
    options_type: Option<&str>,
    enum_fields: &HashMap<String, String>,
    result_is_simple: bool,
) {
    let test_name = sanitize_ident(&fixture.id);
    let description = fixture.description.replace('\'', "\\'");
    let expects_error = fixture.assertions.iter().any(|a| a.assertion_type == "error");

    let (setup_lines, args_str) = build_args_and_setup(
        &fixture.input,
        args,
        call_receiver,
        options_type,
        enum_fields,
        result_is_simple,
        &fixture.id,
    );

    let call_expr = format!("{call_receiver}.{function_name}({args_str})");

    let _ = writeln!(out, "  it '{test_name}: {description}' do");

    for line in &setup_lines {
        let _ = writeln!(out, "    {line}");
    }

    if expects_error {
        let _ = writeln!(out, "    expect {{ {call_expr} }}.to raise_error");
        let _ = writeln!(out, "  end");
        return;
    }

    // Check if any non-error assertion actually uses the result variable.
    let has_usable = has_usable_assertion(fixture, field_resolver, result_is_simple);
    if has_usable {
        let _ = writeln!(out, "    {result_var} = {call_expr}");
    } else {
        let _ = writeln!(out, "    {call_expr}");
    }

    for assertion in &fixture.assertions {
        render_assertion(out, assertion, result_var, field_resolver, result_is_simple);
    }

    let _ = writeln!(out, "  end");
}

/// Build setup lines (e.g. handle creation) and the argument list for the function call.
///
/// Returns `(setup_lines, args_string)`.
fn build_args_and_setup(
    input: &serde_json::Value,
    args: &[crate::config::ArgMapping],
    call_receiver: &str,
    options_type: Option<&str>,
    enum_fields: &HashMap<String, String>,
    result_is_simple: bool,
    fixture_id: &str,
) -> (Vec<String>, String) {
    if args.is_empty() {
        return (Vec::new(), json_to_ruby(input));
    }

    let mut setup_lines: Vec<String> = Vec::new();
    let mut parts: Vec<String> = Vec::new();

    for arg in args {
        if arg.arg_type == "mock_url" {
            setup_lines.push(format!(
                "{} = \"#{{ENV.fetch('MOCK_SERVER_URL')}}/fixtures/{fixture_id}\"",
                arg.name,
            ));
            parts.push(arg.name.clone());
            continue;
        }

        if arg.arg_type == "handle" {
            // Generate a create_engine (or equivalent) call and pass the variable.
            let constructor_name = format!("create_{}", arg.name.to_snake_case());
            let config_value = input.get(&arg.field).unwrap_or(&serde_json::Value::Null);
            if config_value.is_null()
                || config_value.is_object() && config_value.as_object().is_some_and(|o| o.is_empty())
            {
                setup_lines.push(format!("{} = {call_receiver}.{constructor_name}(nil)", arg.name,));
            } else {
                let literal = json_to_ruby(config_value);
                let name = &arg.name;
                setup_lines.push(format!("{name}_config = {literal}"));
                setup_lines.push(format!(
                    "{} = {call_receiver}.{constructor_name}({name}_config.to_json)",
                    arg.name,
                    name = name,
                ));
            }
            parts.push(arg.name.clone());
            continue;
        }

        let val = input.get(&arg.field);
        match val {
            None | Some(serde_json::Value::Null) if arg.optional => {
                // Optional arg with no fixture value: skip entirely.
                continue;
            }
            None | Some(serde_json::Value::Null) => {
                // Required arg with no fixture value: pass a language-appropriate default.
                let default_val = match arg.arg_type.as_str() {
                    "string" => "''".to_string(),
                    "int" | "integer" => "0".to_string(),
                    "float" | "number" => "0.0".to_string(),
                    "bool" | "boolean" => "false".to_string(),
                    _ => "nil".to_string(),
                };
                parts.push(default_val);
            }
            Some(v) => {
                // For json_object args with options_type, construct a typed options object.
                // When result_is_simple, the binding accepts a plain Hash (no wrapper class).
                if arg.arg_type == "json_object" && !v.is_null() {
                    if let (Some(opts_type), Some(obj)) = (options_type, v.as_object()) {
                        let kwargs: Vec<String> = obj
                            .iter()
                            .map(|(k, vv)| {
                                let snake_key = k.to_snake_case();
                                let rb_val = if enum_fields.contains_key(k) {
                                    if let Some(s) = vv.as_str() {
                                        let snake_val = s.to_snake_case();
                                        format!("'{snake_val}'")
                                    } else {
                                        json_to_ruby(vv)
                                    }
                                } else {
                                    json_to_ruby(vv)
                                };
                                format!("{snake_key}: {rb_val}")
                            })
                            .collect();
                        if result_is_simple {
                            parts.push(format!("{{{}}}", kwargs.join(", ")));
                        } else {
                            parts.push(format!("{opts_type}.new({})", kwargs.join(", ")));
                        }
                        continue;
                    }
                }
                parts.push(json_to_ruby(v));
            }
        }
    }

    (setup_lines, parts.join(", "))
}

fn render_assertion(
    out: &mut String,
    assertion: &Assertion,
    result_var: &str,
    field_resolver: &FieldResolver,
    result_is_simple: bool,
) {
    // Skip assertions on fields that don't exist on the result type.
    if let Some(f) = &assertion.field {
        if !f.is_empty() && !field_resolver.is_valid_for_result(f) {
            // Don't emit skip comments — the example-level filter ensures we only
            // get here in mixed cases, and the comment would be noise.
            return;
        }
    }

    // When result_is_simple, skip assertions that reference non-content fields.
    if result_is_simple {
        if let Some(f) = &assertion.field {
            let f_lower = f.to_lowercase();
            if !f.is_empty()
                && f_lower != "content"
                && (f_lower.starts_with("metadata")
                    || f_lower.starts_with("document")
                    || f_lower.starts_with("structure"))
            {
                return;
            }
        }
    }

    let field_expr = if result_is_simple {
        result_var.to_string()
    } else {
        match &assertion.field {
            Some(f) if !f.is_empty() => field_resolver.accessor(f, "ruby", result_var),
            _ => result_var.to_string(),
        }
    };

    // For string equality, strip trailing whitespace to handle trailing newlines
    // from the converter.
    let stripped_field_expr = if result_is_simple {
        format!("{field_expr}.strip")
    } else {
        field_expr.clone()
    };

    match assertion.assertion_type.as_str() {
        "equals" => {
            if let Some(expected) = &assertion.value {
                // Use be(true)/be(false) for booleans (RSpec/BeEq).
                if let Some(b) = expected.as_bool() {
                    let _ = writeln!(out, "    expect({stripped_field_expr}).to be({b})");
                } else {
                    let rb_val = json_to_ruby(expected);
                    let _ = writeln!(out, "    expect({stripped_field_expr}).to eq({rb_val})");
                }
            }
        }
        "contains" => {
            if let Some(expected) = &assertion.value {
                let rb_val = json_to_ruby(expected);
                // Use .to_s to handle both String and Symbol (enum) fields
                let _ = writeln!(out, "    expect({field_expr}.to_s).to include({rb_val})");
            }
        }
        "contains_all" => {
            if let Some(values) = &assertion.values {
                for val in values {
                    let rb_val = json_to_ruby(val);
                    let _ = writeln!(out, "    expect({field_expr}.to_s).to include({rb_val})");
                }
            }
        }
        "not_contains" => {
            if let Some(expected) = &assertion.value {
                let rb_val = json_to_ruby(expected);
                let _ = writeln!(out, "    expect({field_expr}.to_s).not_to include({rb_val})");
            }
        }
        "not_empty" => {
            let _ = writeln!(out, "    expect({field_expr}).not_to be_empty");
        }
        "is_empty" => {
            // Handle nil (None) as empty for optional fields
            let _ = writeln!(out, "    expect({field_expr}.nil? || {field_expr}.empty?).to be(true)");
        }
        "contains_any" => {
            if let Some(values) = &assertion.values {
                let items: Vec<String> = values.iter().map(json_to_ruby).collect();
                let arr_str = items.join(", ");
                let _ = writeln!(
                    out,
                    "    expect([{arr_str}].any? {{ |v| {field_expr}.to_s.include?(v) }}).to be(true)"
                );
            }
        }
        "greater_than" => {
            if let Some(val) = &assertion.value {
                let rb_val = json_to_ruby(val);
                let _ = writeln!(out, "    expect({field_expr}).to be > {rb_val}");
            }
        }
        "less_than" => {
            if let Some(val) = &assertion.value {
                let rb_val = json_to_ruby(val);
                let _ = writeln!(out, "    expect({field_expr}).to be < {rb_val}");
            }
        }
        "greater_than_or_equal" => {
            if let Some(val) = &assertion.value {
                let rb_val = json_to_ruby(val);
                let _ = writeln!(out, "    expect({field_expr}).to be >= {rb_val}");
            }
        }
        "less_than_or_equal" => {
            if let Some(val) = &assertion.value {
                let rb_val = json_to_ruby(val);
                let _ = writeln!(out, "    expect({field_expr}).to be <= {rb_val}");
            }
        }
        "starts_with" => {
            if let Some(expected) = &assertion.value {
                let rb_val = json_to_ruby(expected);
                let _ = writeln!(out, "    expect({field_expr}).to start_with({rb_val})");
            }
        }
        "ends_with" => {
            if let Some(expected) = &assertion.value {
                let rb_val = json_to_ruby(expected);
                let _ = writeln!(out, "    expect({field_expr}).to end_with({rb_val})");
            }
        }
        "min_length" => {
            if let Some(val) = &assertion.value {
                if let Some(n) = val.as_u64() {
                    let _ = writeln!(out, "    expect({field_expr}.length).to be >= {n}");
                }
            }
        }
        "max_length" => {
            if let Some(val) = &assertion.value {
                if let Some(n) = val.as_u64() {
                    let _ = writeln!(out, "    expect({field_expr}.length).to be <= {n}");
                }
            }
        }
        "count_min" => {
            if let Some(val) = &assertion.value {
                if let Some(n) = val.as_u64() {
                    let _ = writeln!(out, "    expect({field_expr}.length).to be >= {n}");
                }
            }
        }
        "not_error" => {
            // Already handled by the call succeeding without exception.
        }
        "error" => {
            // Handled at the example level.
        }
        other => {
            let _ = writeln!(out, "    # TODO: unsupported assertion type: {other}");
        }
    }
}

/// Convert a module path (e.g., "html_to_markdown") to Ruby PascalCase module name
/// (e.g., "HtmlToMarkdown").
fn ruby_module_name(module_path: &str) -> String {
    use heck::ToUpperCamelCase;
    module_path.to_upper_camel_case()
}

/// Convert a `serde_json::Value` to a Ruby literal string, preferring single quotes.
fn json_to_ruby(value: &serde_json::Value) -> String {
    match value {
        serde_json::Value::String(s) => ruby_string_literal(s),
        serde_json::Value::Bool(true) => "true".to_string(),
        serde_json::Value::Bool(false) => "false".to_string(),
        serde_json::Value::Number(n) => n.to_string(),
        serde_json::Value::Null => "nil".to_string(),
        serde_json::Value::Array(arr) => {
            let items: Vec<String> = arr.iter().map(json_to_ruby).collect();
            format!("[{}]", items.join(", "))
        }
        serde_json::Value::Object(map) => {
            let items: Vec<String> = map
                .iter()
                .map(|(k, v)| format!("{} => {}", ruby_string_literal(k), json_to_ruby(v)))
                .collect();
            format!("{{ {} }}", items.join(", "))
        }
    }
}