use std::path::{Path, PathBuf};

#[test]
fn canonical_examples_do_not_author_browser_javascript() {
    // req: examples/005
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let examples = root.join("examples");
    let mut failures = Vec::new();
    scan_examples(&examples, &mut |path, text| {
        if path.components().any(|part| part.as_os_str() == "tests") {
            return;
        }
        for (line_no, line) in text.lines().enumerate() {
            let trimmed = line.trim();
            if trimmed.contains("<script") && !allowed_example_script(path, trimmed) {
                failures.push(format!(
                    "{}:{}: only the hemx runtime or explicit opaque-island scripts are allowed",
                    path.display(),
                    line_no + 1
                ));
            }
            if contains_inline_event_handler(trimmed) {
                failures.push(format!(
                    "{}:{}: inline on*= handler is not allowed",
                    path.display(),
                    line_no + 1
                ));
            }
            if trimmed.to_ascii_lowercase().contains("javascript:") {
                failures.push(format!(
                    "{}:{}: javascript: URL is not allowed",
                    path.display(),
                    line_no + 1
                ));
            }
        }
    });

    assert!(failures.is_empty(), "{}", failures.join("\n"));
}

#[test]
fn canonical_examples_do_not_author_low_level_resource_plumbing() {
    // req: dx/002 req: ceremony/002 req: ceremony/004 req: examples/003
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let examples = root.join("examples");
    let forbidden = [
        "ResourceId::new",
        ".id().id",
        "include!(concat!",
        "OUT_DIR",
        "global_exports(",
        "EffectWriter",
        "RuntimeOpcode",
        "data-hid",
        "data-sid",
        "data-fid",
        "data-aid",
        "data-handle-id",
        "data-slot-id",
        "data-form-id",
        "data-atom-id",
        "::lower(include_str!",
        "lower_html(",
        "render_html(",
        "HandlerRegistry",
        ".into_registry()",
        "InteractionForm",
        "register_handle(",
        "SafeHtml",
        "hemx::advanced",
        "advanced::slots",
        "KeyedSlot",
        "Slot<",
        "Effect::",
        "Payload::",
        "NavigateMode",
        "ScopeKey",
        "opcode",
        "wire format",
        "manual generated",
        "RenderSlotExt",
        "RenderKeyedSlotExt",
        ".render(&",
        ".html(ui::render",
        ".html(hemx::render",
        ".html(super::ui::render",
        "ui::put(",
        "ui::append(",
        "ui::replace(",
        "application/hemx",
        "EffectBatch",
        "__h=",
        "name=\"__h\"",
        "name='__h'",
    ];
    let mut failures = Vec::new();
    scan_examples(&examples, &mut |path, text| {
        if path.components().any(|part| part.as_os_str() == "tests") {
            return;
        }
        let Some(ext) = path.extension().and_then(|ext| ext.to_str()) else {
            return;
        };
        if !matches!(ext, "rs" | "heml" | "html") {
            return;
        }
        let runtime_source = if ext == "rs" {
            text.split("#[cfg(test)]").next().unwrap_or(text)
        } else {
            text
        };
        for (line_no, line) in runtime_source.lines().enumerate() {
            if let Some(token) = forbidden.iter().find(|token| line.contains(*token)) {
                failures.push(format!(
                    "{}:{}: example runtime code must use generated resources, not `{token}`",
                    path.display(),
                    line_no + 1
                ));
            }
        }
    });

    assert!(failures.is_empty(), "{}", failures.join("\n"));
}

#[test]
fn public_prelude_does_not_export_low_level_primitives() {
    // req: public_api/005 req: dx/006
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let facade = std::fs::read_to_string(root.join("hemx/src/lib.rs")).unwrap();
    let prelude = facade
        .split("pub mod prelude {")
        .nth(1)
        .and_then(|tail| tail.split("\n}").next())
        .expect("hemx facade exposes prelude module");
    let exported = prelude
        .split(|c: char| !(c == '_' || c.is_ascii_alphanumeric()))
        .filter(|part| !part.is_empty())
        .collect::<Vec<_>>();
    for token in [
        "SafeHtml",
        "Effect",
        "Slot",
        "KeyedSlot",
        "ResourceId",
        "EffectBatch",
        "BuildFingerprint",
        "Atom",
        "ComponentRef",
        "EventName",
        "GeneratedTarget",
        "Handle",
        "ParamName",
        "page",
    ] {
        assert!(
            !exported.contains(&token),
            "hemx::prelude must not export low-level `{token}`"
        );
    }
    assert!(prelude.contains("Html"), "hemx::prelude should export Html");
    assert!(
        prelude.contains("IntoEffect"),
        "hemx::prelude should export IntoEffect"
    );
}

#[test]
fn canonical_example_docs_do_not_teach_low_level_plumbing() {
    // req: dx/002 req: dx/003 req: examples/003
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let examples = root.join("examples");
    let forbidden = [
        "generated handles and slots",
        "generated hemx handles",
        "generated handle ids",
        "numeric handle ids",
        "runtime lowering",
        "application/hemx responses",
        "EffectBatch",
        "manual registry",
        "HandlerRegistry",
        ".into_registry()",
        "InteractionForm",
        "register_handle(",
        "lower_html(",
        "render_html(",
        "SafeHtml",
        "KeyedSlot",
        "Slot<",
        "Effect::",
        "opcode",
        "wire format",
        "manual generated",
        "Effect::batch",
        "Effect::class",
        "Effect::move",
        "Effect::set",
        "Effect::broadcast",
        "Effect::ack",
        "SyncEffect::",
        "postcard DOM ops",
        "data-hid",
        "data-sid",
        ".render(&",
        "addEventListener(",
        "querySelector",
        "querySelectorAll",
    ];
    let mut failures = Vec::new();
    scan_examples(&examples, &mut |path, text| {
        if path.extension().and_then(|ext| ext.to_str()) != Some("md")
            || is_advanced_boundary_doc(text)
        {
            return;
        }
        for (line_no, line) in text.lines().enumerate() {
            if let Some(token) = forbidden.iter().find(|token| line.contains(*token)) {
                failures.push(format!(
                    "{}:{}: example docs must teach generated ergonomic APIs, not `{token}`",
                    path.display(),
                    line_no + 1
                ));
            }
        }
    });

    assert!(failures.is_empty(), "{}", failures.join("\n"));
}

#[test]
fn example_docs_do_not_show_runtime_metadata_as_authoring_contract() {
    // req: dx/006 req: misc/006
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let examples = root.join("examples");
    let forbidden = [
        "data-hid",
        "data-sid",
        "data-aid",
        "data-fid",
        "[data-hid",
        "[data-sid",
    ];
    let mut failures = Vec::new();
    scan_examples(&examples, &mut |path, text| {
        if path.extension().and_then(|ext| ext.to_str()) != Some("md") {
            return;
        }
        for (line_no, line) in text.lines().enumerate() {
            if let Some(token) = forbidden.iter().find(|token| line.contains(*token)) {
                failures.push(format!(
                    "{}:{}: example docs must describe generated authoring APIs, not runtime metadata `{token}`",
                    path.display(),
                    line_no + 1
                ));
            }
        }
    });

    assert!(failures.is_empty(), "{}", failures.join("\n"));
}

#[test]
fn browser_e2e_does_not_shortcut_product_interactions() {
    // req: examples/005
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let browser_e2e = root.join("examples/techdemo/tests/browser_e2e.rs");
    let source = std::fs::read_to_string(browser_e2e).unwrap();

    assert!(
        !source.contains("fetch(\"/\""),
        "browser E2E must drive UI, not post directly"
    );
    assert!(
        !source.contains("applyBatch(buffer"),
        "browser E2E must not apply wire batches manually"
    );
}

#[test]
fn html_examples_slot_targets_dispatch_to_component_put() {
    // req: runtime/005 req: examples/001 req: htmx_equivalents/001
    // Regression: slots named after a component (e.g. contact_card, editable_row)
    // must lower injected partials using that component's handle table, not the
    // containing page's handle table.
    let root = Path::new(env!("CARGO_MANIFEST_DIR")).parent().unwrap();
    let template_dir = root.join("examples/html_examples/templates");
    let out_dir = std::env::temp_dir().join(format!(
        "hemx-test-html-examples-slot-targets-{}",
        std::process::id()
    ));

    let _ = std::fs::remove_dir_all(&out_dir);
    std::fs::create_dir_all(&out_dir).unwrap();

    let result = std::panic::catch_unwind(|| {
        hemx_build::app()
            .template_dir(&template_dir)
            .out_dir(&out_dir)
            .run()
            .expect("hemx-build should generate html_examples artifacts");

        let generated =
            std::fs::read_to_string(out_dir.join("hemx.generated.rs")).unwrap_or_default();

        for component in ["contact_card", "editable_row"] {
            let component_path = format!("super::super::{component}");
            let impl_header = format!("impl<T> SlotTarget<T, {component_path}::Component>");
            let put_call = format!("{component_path}::put(self.slot, view)");
            assert!(
                generated.contains(&impl_header),
                "gallery::targets should have a component-specific SlotTarget impl for `{component}`; missing `{impl_header}`"
            );
            assert!(
                generated.contains(&put_call),
                "gallery::targets::{component} put/replace should dispatch to `{component_path}::put`; missing `{put_call}`"
            );
        }
    });

    let _ = std::fs::remove_dir_all(&out_dir);
    result.unwrap();
}

fn scan_examples(dir: &Path, visit: &mut impl FnMut(&Path, &str)) {
    for entry in std::fs::read_dir(dir).unwrap() {
        let entry = entry.unwrap();
        let path = entry.path();
        if path.is_dir() {
            scan_examples(&path, visit);
            continue;
        }
        if !is_example_source(&path) {
            continue;
        }
        let text = std::fs::read_to_string(&path).unwrap();
        visit(&path, &text);
    }
}

fn is_advanced_boundary_doc(text: &str) -> bool {
    text.contains("advanced/low-level north-star boundary sketch")
}

fn is_example_source(path: &PathBuf) -> bool {
    matches!(
        path.extension().and_then(|ext| ext.to_str()),
        Some("rs" | "heml" | "html" | "md")
    )
}

fn allowed_example_script(path: &Path, line: &str) -> bool {
    // req: examples/005
    line.contains(r#"<script +src="self.runtime_src" defer></script>"#)
        || (path.ends_with("examples/techdemo/templates/app_shell.heml")
            && line.contains(r#"<script src="/island.js" defer></script>"#))
        || (path.ends_with("examples/saas/templates/app_shell.heml")
            && line.contains(r#"<script src="/metrics.js" defer></script>"#))
}

fn contains_inline_event_handler(line: &str) -> bool {
    let bytes = line.as_bytes();
    let mut i = 0;
    while i + 3 < bytes.len() {
        let boundary = bytes[i].is_ascii_whitespace() || bytes[i] == b'<';
        if boundary
            && bytes[i + 1] == b'o'
            && bytes[i + 2] == b'n'
            && bytes[i + 3].is_ascii_lowercase()
        {
            let mut j = i + 4;
            while j < bytes.len() && bytes[j].is_ascii_lowercase() {
                j += 1;
            }
            while j < bytes.len() && bytes[j].is_ascii_whitespace() {
                j += 1;
            }
            if j < bytes.len() && bytes[j] == b'=' {
                return true;
            }
        }
        i += 1;
    }
    false
}