#include "dispatch.h"
#include <unordered_map>
#include "pico/stdlib.h"
#include "tusb.h"
#include "wire.h"
#include "usb_cdc.h"
#include "timer_queue.h"
#include "net.h"
#include "igmp.h"
#include "debug_log.h"
#include "hardware/sync.h"

static timer_queue timers;

static void igmp_reannounce() {
    auto& ns = net_get_state();
    igmp::send_all_reports(ns.mac, ns.ip, net_send_raw);
    dispatch_schedule_ms(60000, igmp_reannounce);
}

void dispatch_init() {
    tusb_init();
    net_init();
    dispatch_schedule_ms(60000, igmp_reannounce);
    dlog("dispatch_init complete");
}

timer_handle dispatch_schedule_ms(uint32_t ms, std::function<void()> fn) {
    auto h = timers.schedule_ms(ms, std::move(fn));
    if (!h) dlogf("timer alloc failed: %lu ms", static_cast<unsigned long>(ms));
    return h;
}

bool dispatch_cancel_timer(timer_handle h) {
    return timers.cancel(h);
}

[[noreturn]] void dispatch_run(std::span<const handler_entry> handlers) {
    std::unordered_map<int8_t, handler_fn> handler_map;
    for (auto& entry : handlers) {
        handler_map[entry.type_id] = entry.handle;
    }

    static usb_cdc usb;
    static static_vector<uint8_t, 256> usb_rx_buf;
    static std::array<uint8_t, 1514> tx_buf;

    auto dispatch_msg = [&](const DecodedMessage& msg, std::function<void(std::span<const uint8_t>)> send) {
        auto it = handler_map.find(msg.type_id);
        if (it == handler_map.end()) {
            dlogf("dispatch: unknown type_id %d", msg.type_id);
            return;
        }
        responder resp{msg.message_id, std::move(send)};
        it->second(resp, msg.payload);
    };

    net_set_handler([&](std::span<const uint8_t> payload,
                        std::function<void(std::span<const uint8_t>)> send) {
        auto msg = try_decode(payload.data(), payload.size());
        if (!msg) return;
        dispatch_msg(*msg, std::move(send));
    });

    while (true) {
        uint32_t save = save_and_disable_interrupts();

        dlog_if_slow("tud_task", 1000, [&]{ tud_task(); });
        dlog_if_slow("drain", 1000, [&]{ usb.drain(); });
        dlog_if_slow("timers", 1000, [&]{ timers.run(); });
        dlog_if_slow("net_poll", 1000, [&]{ net_poll(std::span{tx_buf}); });

        while (tud_cdc_available()) {
            uint8_t byte;
            if (tud_cdc_read(&byte, 1) != 1) break;

            usb_rx_buf.push_back(byte);

            auto msg = try_decode(usb_rx_buf);
            if (!msg) {
                if (usb_rx_buf.full()) usb_rx_buf.clear();
                continue;
            }

            dispatch_msg(*msg, [&](std::span<const uint8_t> data) {
                if (data.size() <= usb.tx.free()) {
                    if (!usb.send(data))
                        dlogf("usb send failed: %zu bytes, %u free", data.size(), usb.tx.free());
                } else {
                    dlogf("usb response too large: %zu bytes, %u free", data.size(), usb.tx.free());
                    uint8_t err_buf[256];
                    span_writer err_out(err_buf, sizeof(err_buf));
                    auto err = encode_response_into(err_out, msg->message_id,
                        [&]{
                            char m[48];
                            snprintf(m, sizeof(m), "response too large: %zu", data.size());
                            return DeviceError{2, m};
                        }());
                    if (err) usb.send(std::span<const uint8_t>{err_buf, *err});
                }
            });
            usb_rx_buf.clear();
        }

        __wfi();
        restore_interrupts(save);
    }
}