// std.http S7a (PLAN-HTTPZ): a live single-worker server and its
// clients driven in ONE thread via Server.tick — keep-alive reuse,
// POST body echo, the per-connection request cap closing politely,
// 404 routing, and half-a-header eviction at the request deadline
// while the server keeps serving others.
#import "modules/std.sx";

PORT :: 18933;

handler :: (req: *http.Request, resp: *http.Response, ctx: usize) {
    if req.path == "/hello" {
        resp.body = concat("hello ", req.method);
        // the ctx word arrives verbatim (init passed 77)
        if ctx != 77 { resp.status = 500; resp.body = "ctx lost"; }
        return;
    }
    if req.path == "/echo" {
        resp.body = req.body;
        return;
    }
    resp.status = 404;
    resp.body = "nope";
}

contains :: (hay: string, needle: string) -> bool {
    if needle.len > hay.len { return false; }
    i := 0;
    while i + needle.len <= hay.len {
        j := 0;
        ok := true;
        while j < needle.len {
            if hay[i + j] != needle[j] { ok = false; break; }
            j += 1;
        }
        if ok { return true; }
        i += 1;
    }
    return false;
}

// Connect a nonblocking loopback client.
dial :: () -> i32 {
    fd := socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0);
    if fd < 0 { return -1; }
    addr : socket.SockAddr = .{
        sin_len = 16, sin_family = xx socket.AF_INET,
        sin_port = socket.htons(PORT), sin_addr = 0x0100007F,
    };
    if socket.connect(fd, @addr, 16) != 0 { socket.close(fd); return -1; }
    if !socket.set_nonblocking(fd) { socket.close(fd); return -1; }
    return fd;
}

// True when `buf[0..len]` holds a complete response (headers + body).
resp_complete :: (buf: [*]u8, len: i64) -> bool {
    s := string.{ ptr = buf, len = xx len };
    he := -1;
    i := 0;
    while i + 3 < s.len {
        if s[i] == 13 and s[i+1] == 10 and s[i+2] == 13 and s[i+3] == 10 { he = i; break; }
        i += 1;
    }
    if he < 0 { return false; }
    // Content-Length digits
    cl : i64 = 0;
    seen := false;
    j := 0;
    needle := "Content-Length: ";
    while j + needle.len < s.len {
        k := 0;
        ok := true;
        while k < needle.len { if s[j + k] != needle[k] { ok = false; break; } k += 1; }
        if ok {
            d := j + needle.len;
            while d < s.len and s[d] >= 48 and s[d] <= 57 { cl = cl * 10 + (s[d] - 48); d += 1; }
            seen = true;
            break;
        }
        j += 1;
    }
    if !seen { return false; }
    return len >= he + 4 + cl;
}

// Send a request and tick the server until its full response arrives.
// Returns the response text ("" = the connection closed instead).
roundtrip :: (srv: *http.Server, fd: i32, reqtext: string, scratch: [*]u8) -> string {
    socket.write(fd, reqtext.ptr, xx reqtext.len);
    total : i64 = 0;
    tries := 0;
    while tries < 400 {
        srv.tick(5) catch {};
        n, re := socket.read_nb(fd, @scratch[total], xx (4096 - total));
        if !re { total += n; }
        else if re == error.Closed { return string.{ ptr = scratch, len = xx total }; }
        if resp_complete(scratch, total) { return string.{ ptr = scratch, len = xx total }; }
        tries += 1;
    }
    return "";
}

main :: () -> i32 {
    cfg : http.Config = .{
        port = PORT,
        timeout_request_ms = 150,
        timeout_keepalive_ms = 400,
        request_count = 3,
        max_conn = 8,
    };
    srv, se := http.Server.init(cfg, handler, 77);
    if se { print("server init failed\n"); return 1; }

    buf : [4096]u8 = ---;

    // ── 1. GET, keep-alive default ────────────────────────────────────
    c1 := dial();
    if c1 < 0 { print("dial failed\n"); return 1; }
    r1 := roundtrip(@srv, c1, "GET /hello HTTP/1.1\r\nHost: t\r\n\r\n", @buf[0]);
    if !contains(r1, "HTTP/1.1 200 OK") { print("case1: bad status\n"); return 1; }
    if !contains(r1, "hello GET") { print("case1: bad body\n"); return 1; }
    if !contains(r1, "Connection: keep-alive") { print("case1: expected keep-alive\n"); return 1; }
    print("GET 200, keep-alive\n");

    // ── 2. same socket again: the connection was actually reused ─────
    r2 := roundtrip(@srv, c1, "GET /hello HTTP/1.1\r\nHost: t\r\n\r\n", @buf[0]);
    if !contains(r2, "hello GET") { print("case2: keep-alive reuse failed\n"); return 1; }
    print("keep-alive reuse ok\n");

    // ── 3. third request hits request_count: Connection: close + EOF ─
    r3 := roundtrip(@srv, c1, "GET /hello HTTP/1.1\r\nHost: t\r\n\r\n", @buf[0]);
    if !contains(r3, "Connection: close") { print("case3: expected close at cap\n"); return 1; }
    drained := false;
    tries := 0;
    while !drained and tries < 200 {
        srv.tick(5) catch {};
        zq, ze := socket.read_nb(c1, @buf[0], 64);
        if ze == error.Closed { drained = true; }
        if !ze and zq == 0 { drained = true; }
        tries += 1;
    }
    if !drained { print("case3: server did not close at the cap\n"); return 1; }
    socket.close(c1);
    print("request cap: close + EOF\n");

    // ── 4. POST body echo ─────────────────────────────────────────────
    c2 := dial();
    if c2 < 0 { print("dial2 failed\n"); return 1; }
    r4 := roundtrip(@srv, c2, "POST /echo HTTP/1.1\r\nHost: t\r\nContent-Length: 9\r\n\r\nping-pong", @buf[0]);
    if !contains(r4, "ping-pong") { print("case4: body not echoed\n"); return 1; }
    print("POST echo ok\n");

    // ── 5. unknown path routes 404 ────────────────────────────────────
    r5 := roundtrip(@srv, c2, "GET /missing HTTP/1.1\r\nHost: t\r\n\r\n", @buf[0]);
    if !contains(r5, "HTTP/1.1 404 Not Found") { print("case5: expected 404\n"); return 1; }
    socket.close(c2);
    print("404 routing ok\n");

    // ── 5b. a body past READ_BUF_INITIAL forces the buffer to grow ────
    big_n := 50000;
    payload : [*]u8 = xx context.allocator.alloc_bytes(xx big_n);
    f := 0;
    while f < big_n { payload[f] = 97 + cast(u8)(f % 26); f += 1; }
    breq := concat("POST /echo HTTP/1.1\r\nHost: t\r\nContent-Length: ", concat(int_to_string(big_n), "\r\n\r\n"));
    breq = concat(breq, string.{ ptr = payload, len = xx big_n });
    c2b := dial();
    if c2b < 0 { print("dial2b failed\n"); return 1; }
    bigbuf : [*]u8 = xx context.allocator.alloc_bytes(xx (big_n + 4096));
    socket.write(c2b, breq.ptr, xx breq.len);
    btotal : i64 = 0;
    btries := 0;
    while btries < 2000 {
        srv.tick(5) catch {};
        bn, bre := socket.read_nb(c2b, @bigbuf[btotal], xx (big_n + 4096 - btotal));
        if !bre { btotal += bn; }
        else if bre == error.Closed { break; }
        if resp_complete(bigbuf, btotal) { break; }
        btries += 1;
    }
    bresp := string.{ ptr = bigbuf, len = xx btotal };
    if !contains(bresp, "HTTP/1.1 200 OK") { print("case5b: big echo not 200\n"); return 1; }
    if !contains(bresp, concat("Content-Length: ", int_to_string(big_n))) { print("case5b: wrong echo length\n"); return 1; }
    if bigbuf[btotal - 1] != 97 + cast(u8)((big_n - 1) % 26) { print("case5b: tail byte wrong\n"); return 1; }
    socket.close(c2b);
    print("big body grows the buffer and echoes intact\n");

    // ── 6. half a header is evicted at the request deadline, while a
    //       healthy client keeps being served ──────────────────────────
    c3 := dial();
    if c3 < 0 { print("dial3 failed\n"); return 1; }
    half := "GET /hel";
    socket.write(c3, half.ptr, xx half.len);
    gone := event.deadline_in(300);   // > timeout_request_ms
    while !event.expired(gone) { srv.tick(5) catch {}; }
    c4 := dial();
    if c4 < 0 { print("dial4 failed\n"); return 1; }
    r6 := roundtrip(@srv, c4, "GET /hello HTTP/1.1\r\nHost: t\r\n\r\n", @buf[0]);
    if !contains(r6, "hello GET") { print("case6: healthy client starved\n"); return 1; }
    evicted := false;
    tries = 0;
    while !evicted and tries < 200 {
        srv.tick(5) catch {};
        zq2, ze2 := socket.read_nb(c3, @buf[0], 64);
        if ze2 == error.Closed { evicted = true; }
        if !ze2 and zq2 == 0 { evicted = true; }
        tries += 1;
    }
    if !evicted { print("case6: half-header connection never evicted\n"); return 1; }
    socket.close(c3);
    socket.close(c4);
    print("slow client evicted, healthy client served\n");

    srv.close();
    print("http server ok\n");
    return 0;
}