use scraper::{Html, Selector};
use hemx_techdemo::ui::control_center::{self as control, launch_work, reset_demo, simulate_push};
use hemx_techdemo::ui::issue_card::{advance_work, delete_work, spotlight_work};
use hemx_techdemo::ui::issue_lane::move_to_lane as move_to_lane_handle;
use hemx_techdemo::ui::BUILD_FINGERPRINT;
use hemx_test::{
    class_descendant_selector, class_selector, handle_form_body, inspect_wire,
    island_attribute_name, island_event_name, island_selector, island_snapshot_marker,
    root_selector, sse_endpoint_marker, strong_text_selector, unknown_handle_form_body,
    EffectInspector,
};
use std::io::{Read, Write};
use std::net::TcpStream;
use std::process::{Child, Command, Stdio};
use std::time::{Duration, Instant};

const ADDR: &str = "127.0.0.1:3002";

struct Server {
    child: Child,
}

impl Server {
    fn start() -> Self {
        let bin = env!("CARGO_BIN_EXE_hemx-techdemo");
        let child = Command::new(bin)
            .stdout(Stdio::null())
            .stderr(Stdio::null())
            .spawn()
            .expect("start hemx-techdemo");

        let deadline = Instant::now() + Duration::from_secs(5);
        while Instant::now() < deadline {
            if TcpStream::connect(ADDR).is_ok() {
                return Self { child };
            }
            std::thread::sleep(Duration::from_millis(25));
        }
        panic!("hemx-techdemo did not listen on {ADDR}");
    }
}

impl Drop for Server {
    fn drop(&mut self) {
        let _ = self.child.kill();
        let _ = self.child.wait();
    }
}

#[test]
fn product_is_e2e_working_over_http() {
    // req: examples/001 req: dx/008 req: form/002 req: page_swap/002 req: push/003
    let _server = Server::start();

    let home = get("/");
    assert_eq!(home.status, 200);
    assert!(home.header("content-type").contains("text/html"));
    let document = Html::parse_document(home.text());
    assert_text(
        &document,
        "A Linear-class work system without a frontend framework",
    );
    assert_text(&document, "Compile checked handles");
    assert_text(&document, "Stream typed presence");
    assert_selector_count_at_least(&document, &root_selector("techdemo"), 1);
    assert_work_card_count_at_least(&document, 3);
    assert_selector_count_at_least(&document, &island_selector("orbit"), 1);
    assert_text(&document, "Opaque island bridge");
    assert!(home.text().contains(island_snapshot_marker()));
    assert!(home.text().contains(&sse_endpoint_marker("/events")));
    assert!(home.text().contains("/island.js"));

    let favicon = get("/favicon.ico");
    assert_eq!(favicon.status, 204);

    let runtime = get("/hemx.js");
    assert_eq!(runtime.status, 200);
    assert!(runtime.header("content-type").contains("javascript"));

    let island = get("/island.js");
    assert_eq!(island.status, 200);
    assert!(island.header("content-type").contains("javascript"));
    assert!(island.text().contains(&island_event_name("orbit")));
    assert!(island.text().contains(island_attribute_name()));
    assert!(island.text().contains("MutationObserver"));
    assert!(island.text().contains("removeEventListener"));

    let architecture = request("GET", "/architecture", &[("X-HEMX-Partial", "1")], "");
    assert_eq!(architecture.status, 200);
    assert!(architecture.header("x-hemx-partial").contains("true"));
    let architecture_doc = Html::parse_document(architecture.text());
    assert_text(&architecture_doc, "Page swap");
    assert_text(&architecture_doc, "hemx-build");

    let launch = post(
        "/",
        &handle_form_body(
            launch_work,
            &[
                ("title", "Design hero moment"),
                ("lane", "product"),
                ("impact", "9"),
            ],
        ),
    );
    assert_effect_response(&launch);
    let launch_batch = launch.effects();
    assert_payload_contains(&launch_batch, "Design hero moment");
    assert_card(
        &launch_batch,
        "Design hero moment",
        "Product",
        "Draft",
        "width:99%",
    );
    assert_payload_contains(&launch_batch, "Launch accepted");
    assert_payload_contains(&launch_batch, "Launched card #4");
    assert_emit(&launch_batch, &island_event_name("orbit"), "activity rows");
    assert!(
        launch_batch.op_count() >= 6,
        "launch should update generated targets and notify the island"
    );

    let default_impact = post(
        "/",
        &handle_form_body(
            launch_work,
            &[("title", "Default impact"), ("lane", "compiler")],
        ),
    );
    assert_effect_response(&default_impact);
    let default_impact_batch = default_impact.effects();
    assert_payload_contains(&default_impact_batch, "Default impact");
    assert_card(
        &default_impact_batch,
        "Default impact",
        "Compiler",
        "Draft",
        "width:55%",
    );

    let low_impact = post(
        "/",
        &handle_form_body(
            launch_work,
            &[
                ("title", "Low impact"),
                ("lane", "runtime"),
                ("impact", "0"),
            ],
        ),
    );
    assert_effect_response(&low_impact);
    let low_impact_batch = low_impact.effects();
    assert_card(
        &low_impact_batch,
        "Low impact",
        "Runtime",
        "Draft",
        "width:11%",
    );

    let high_impact = post(
        "/",
        &handle_form_body(
            launch_work,
            &[
                ("title", "High impact"),
                ("lane", "runtime"),
                ("impact", "99"),
            ],
        ),
    );
    assert_effect_response(&high_impact);
    let high_impact_batch = high_impact.effects();
    assert_card(
        &high_impact_batch,
        "High impact",
        "Runtime",
        "Draft",
        "width:99%",
    );

    let missing_title = post(
        "/",
        &handle_form_body(launch_work, &[("lane", "runtime"), ("impact", "8")]),
    );
    assert_effect_response(&missing_title);
    let missing_title_batch = missing_title.effects();
    assert_payload_contains(&missing_title_batch, "Launch accepted");
    assert!(missing_title_batch.payload_excludes_key(8));
    assert_payload_not_contains(&missing_title_batch, "MUTATED");

    let move_to_lane = post(
        "/",
        &handle_form_body(
            move_to_lane_handle,
            &[("work_id", "4"), ("lane", "runtime")],
        ),
    );
    assert_effect_response(&move_to_lane);
    let move_to_lane_batch = move_to_lane.effects();
    assert_card(
        &move_to_lane_batch,
        "Design hero moment",
        "Runtime",
        "Active",
        "width:99%",
    );
    assert_payload_contains(&move_to_lane_batch, "Drag-and-drop move persisted");

    let inspect = post("/", &handle_form_body(spotlight_work, &[("work_id", "4")]));
    assert_effect_response(&inspect);
    let inspect_batch = inspect.effects();
    assert_payload_contains(&inspect_batch, "Design hero moment · lane=Runtime");
    assert_payload_contains(&inspect_batch, "Inspector focused");

    let advance = post("/", &handle_form_body(advance_work, &[("work_id", "4")]));
    assert_effect_response(&advance);
    let advance_batch = advance.effects();
    assert_payload_contains(&advance_batch, "Pipeline advanced");
    assert_payload_contains(&advance_batch, "<span class=\"pill\">Active</span>");

    let advance_default = post("/", &handle_form_body(advance_work, &[("work_id", "5")]));
    assert_effect_response(&advance_default);
    let advance_default_batch = advance_default.effects();
    assert_payload_contains(&advance_default_batch, "Default impact");
    assert_card(
        &advance_default_batch,
        "Default impact",
        "Compiler",
        "Active",
        "width:55%",
    );

    let ship_default = post("/", &handle_form_body(advance_work, &[("work_id", "5")]));
    assert_effect_response(&ship_default);
    let ship_default_batch = ship_default.effects();
    assert_card(
        &ship_default_batch,
        "Default impact",
        "Product",
        "Shipped",
        "width:55%",
    );

    let simulated_push = post("/", &handle_form_body(simulate_push, &[]));
    assert_effect_response(&simulated_push);
    let push_batch = simulated_push.effects();
    assert_payload_contains(&push_batch, "SSE tick");
    assert_payload_contains(&push_batch, "Push simulated · no client app code");
    assert_payload_contains(
        &push_batch,
        "Simulated push event produced the same generated update shape",
    );
    assert_emit(&push_batch, &island_event_name("orbit"), "activity rows");

    let delete_missing = post("/", &handle_form_body(delete_work, &[("work_id", "999")]));
    assert_effect_response(&delete_missing);
    let delete_missing_batch = delete_missing.effects();
    assert_payload_not_contains(&delete_missing_batch, "Deleted card #999");

    let delete = post("/", &handle_form_body(delete_work, &[("work_id", "4")]));
    assert_effect_response(&delete);
    let delete_batch = delete.effects();
    assert_payload_contains(&delete_batch, "Card removed");
    assert_payload_contains(&delete_batch, "Deleted card #4");
    assert!(delete_batch.payload_excludes_key(4));
    assert_payload_contains(&delete_batch, "Default impact");

    let reset = post("/", &handle_form_body(reset_demo, &[]));
    assert_effect_response(&reset);
    let reset_batch = reset.effects();
    assert_payload_contains(&reset_batch, "Demo reset from Rust state");
    assert_payload_contains(&reset_batch, "Compile checked handles");

    let sse = get("/events?once=1");
    assert_eq!(sse.status, 200);
    assert!(sse.header("content-type").contains("text/event-stream"));
    assert!(sse.text().contains("event: hemx"));
    assert!(sse.text().contains("data: "));

    let unknown = post("/", &unknown_handle_form_body(999999));
    assert_eq!(unknown.status, 404);
    assert!(unknown.text().contains("unknown hemx handle id 999999"));
}

fn assert_effect_response(response: &Response) {
    assert_eq!(response.status, 200);
    assert!(response.header("content-type").contains("application/hemx"));
    assert_eq!(
        response.header("x-hemx-fingerprint"),
        BUILD_FINGERPRINT.0.to_string()
    );
    assert!(!response.effects().is_empty());
}

fn assert_payload_contains(batch: &EffectInspector, needle: &str) {
    assert!(
        batch.payload_contains(needle),
        "missing payload {needle:?} in {batch:#?}"
    );
}

fn assert_emit(batch: &EffectInspector, name: &str, needle: &str) {
    assert!(
        batch.emits_containing(name, needle),
        "missing emit {name:?} containing {needle:?} in {batch:#?}"
    );
}

fn assert_card(batch: &EffectInspector, title: &str, lane: &str, stage: &str, impact_style: &str) {
    let board = batch
        .target_html_containing(control::board, "class=\"lanes\"")
        .expect("board html payload");
    let document = Html::parse_fragment(&board);
    let lane_selector = Selector::parse(&class_selector("lane")).unwrap();
    let card_selector = Selector::parse(&class_selector("work-card")).unwrap();
    let strong_selector = Selector::parse(strong_text_selector()).unwrap();
    let stage_selector = Selector::parse(&class_selector("pill")).unwrap();
    let impact_selector = Selector::parse(&class_descendant_selector("impact", "i")).unwrap();

    for lane_node in document.select(&lane_selector) {
        let lane_text = lane_node.text().collect::<Vec<_>>().join(" ");
        if !lane_text.contains(lane) {
            continue;
        }
        for card in lane_node.select(&card_selector) {
            let card_title = card
                .select(&strong_selector)
                .next()
                .map(|node| node.text().collect::<String>())
                .unwrap_or_default();
            if card_title != title {
                continue;
            }
            let card_stage = card
                .select(&stage_selector)
                .next()
                .map(|node| node.text().collect::<String>())
                .unwrap_or_default();
            let style = card
                .select(&impact_selector)
                .next()
                .and_then(|node| node.value().attr("style"))
                .unwrap_or("");
            assert_eq!(card_stage, stage);
            assert!(
                style.contains(impact_style),
                "style {style:?} missing {impact_style:?}"
            );
            return;
        }
    }

    panic!("missing card title={title:?} lane={lane:?} in {board}");
}

fn assert_payload_not_contains(batch: &EffectInspector, needle: &str) {
    assert!(
        batch.payload_excludes(needle),
        "unexpected payload {needle:?} in {batch:#?}"
    );
}

fn assert_text(document: &Html, text: &str) {
    let body = document.root_element().text().collect::<Vec<_>>().join(" ");
    assert!(body.contains(text), "missing text {text:?} in {body:?}");
}

fn assert_work_card_count_at_least(document: &Html, expected: usize) {
    assert_selector_count_at_least(document, &class_selector("work-card"), expected);
}

fn assert_selector_count_at_least(document: &Html, selector: &str, expected: usize) {
    let selector = Selector::parse(selector).unwrap();
    let count = document.select(&selector).count();
    assert!(count >= expected, "selector count {count} < {expected}");
}

fn get(path: &str) -> Response {
    request("GET", path, &[], "")
}

fn post(path: &str, body: &str) -> Response {
    request(
        "POST",
        path,
        &[("Content-Type", "application/x-www-form-urlencoded")],
        body,
    )
}

fn request(method: &str, path: &str, headers: &[(&str, &str)], body: &str) -> Response {
    let mut stream = TcpStream::connect(ADDR).expect("connect to server");
    stream
        .set_read_timeout(Some(Duration::from_secs(5)))
        .unwrap();
    write!(
        stream,
        "{method} {path} HTTP/1.1\r\nHost: {ADDR}\r\nConnection: close\r\nContent-Length: {}\r\n",
        body.len()
    )
    .unwrap();
    for (name, value) in headers {
        write!(stream, "{name}: {value}\r\n").unwrap();
    }
    write!(stream, "\r\n{body}").unwrap();

    let mut raw = Vec::new();
    stream.read_to_end(&mut raw).unwrap();
    Response::parse(raw)
}

struct Response {
    status: u16,
    headers: Vec<(String, String)>,
    body: Vec<u8>,
}

impl Response {
    fn parse(raw: Vec<u8>) -> Self {
        let split = raw
            .windows(4)
            .position(|window| window == b"\r\n\r\n")
            .expect("response header terminator");
        let head = String::from_utf8(raw[..split].to_vec()).unwrap();
        let body = raw[split + 4..].to_vec();
        let mut lines = head.lines();
        let status = lines
            .next()
            .and_then(|line| line.split_whitespace().nth(1))
            .and_then(|status| status.parse().ok())
            .expect("status code");
        let headers = lines
            .filter_map(|line| line.split_once(':'))
            .map(|(name, value)| (name.trim().to_ascii_lowercase(), value.trim().to_string()))
            .collect();
        Self {
            status,
            headers,
            body,
        }
    }

    fn header(&self, name: &str) -> &str {
        self.headers
            .iter()
            .find(|(key, _)| key == &name.to_ascii_lowercase())
            .map(|(_, value)| value.as_str())
            .unwrap_or("")
    }

    fn text(&self) -> &str {
        std::str::from_utf8(&self.body).unwrap()
    }

    fn effects(&self) -> EffectInspector {
        inspect_wire(&self.body)
    }
}