#include "drivenengine.hpp"


Channel::Channel(DrivenEngine *de, int chid, int port, const std::string &target) {
    driven_ = de;
    chid_ = chid;
    sb_in_.reset(new StreamBuffer);
    sb_out_.reset(new StreamBuffer);
    port_ = port;
    closed_ = false;
    target_ = target;
    readline_enabled_ = (chid == 0);
    readline_lastc_ = 0;
    desired_prompt_ = "";
    assert(driven_->channels_[chid_] == nullptr);
    driven_->channels_[chid_] = this;
}

Channel::~Channel() {
    assert(driven_->channels_[chid_] == this);
    driven_->new_closed_.insert(chid_);
    driven_->new_outgoing_.erase(chid_);
    driven_->channels_[chid_] = nullptr;
}

void Channel::show_or_hide_command(bool ignore_sb_out) {
    bool sb_out_empty = (sb_out_->fill() == 0) || ignore_sb_out;
    if (!sb_out_empty || (!readline_enabled_) || (driven_->stop_driver_)) {
        int ccsize = current_prompt_.size() + current_command_.size();
        readline_echo_ += util::repeat_string("\b \b", ccsize);
        current_prompt_ = "";
        current_command_ = "";
        return;
    }

    // If the prompt has changed, erase everything and start over.
    if (desired_prompt_ != current_prompt_) {
        int ccsize = current_prompt_.size() + current_command_.size();
        readline_echo_ += util::repeat_string("\b \b", ccsize);
        readline_echo_ += desired_prompt_;
        current_command_ = "";
        current_prompt_ = desired_prompt_;
    }

    // Find out how much of the command matches.
    int match = util::common_prefix_length(current_command_, desired_command_);

    // Echo backspaces to remove the non-matching part.
    int remove = current_command_.size() - match;
    if (remove > 0) {
        readline_echo_ += util::repeat_string("\b \b", remove);
        current_command_ = current_command_.substr(0, match);
    }

    // Echo the new part.
    std::string newpart = desired_command_.substr(current_command_.size());
    if (newpart != "") {
        readline_echo_ += newpart;
        current_command_ = desired_command_;
    }
}

void Channel::set_prompt(const std::string &p) {
    desired_prompt_ = p;
    show_or_hide_command(false);
}

void Channel::feed_readline(int nbytes, const char *bytes) {
    for (int i = 0; i < nbytes; i++) {
        char c = bytes[i];
        if ((c == '\n') && (readline_lastc_ == '\r')) {
            // Ignore newline immediately after carriage return.
            // Otherwise, crlf produces two newlines.
        } else if ((c == '\r') || (c == '\n')) {
            show_or_hide_command(true);
            readline_echo_ = readline_echo_ + " \n";
            sb_in_->write_bytes(desired_command_);
            sb_in_->write_uint8('\n');
            desired_command_ = "";
            current_prompt_ = "";
            current_command_ = "";
        } else if (c == '\b') {
            int len = desired_command_.size();
            if (len > 0) {
                desired_command_ = desired_command_.substr(0, len-1);
            }
        } else if (c >= 32) {
            int len = desired_command_.size();
            if (len < READLINE_MAX) {
                desired_command_ = desired_command_ + c;
            }
        }
        readline_lastc_ = c;
    }
}

void Channel::peek_outgoing(int *nbytes, const char **bytes) {
    show_or_hide_command(false);
    if (readline_echo_.size() > 0) {
        *nbytes = readline_echo_.size();
        *bytes = readline_echo_.c_str();
    } else {
        *nbytes = sb_out_->fill();
        *bytes = sb_out_->data();
    }
}

void Channel::sent_outgoing(int nbytes) {
    if (nbytes > 0) {
        if (readline_echo_.size() > 0) {
            if (nbytes < int(readline_echo_.size())) {
                readline_echo_ = readline_echo_.substr(nbytes);
                return;
            }
            nbytes -= readline_echo_.size();
            readline_echo_ = "";
        }
        sb_out_->read_bytes(nbytes);
    }
}

void Channel::set_readline(bool e) {
    if (e != readline_enabled_) {
        readline_enabled_ = e;
        desired_command_ = "";
        show_or_hide_command(false);
    }
}

int DrivenEngine::find_unused_chid() {
    // Note: channel ID zero is special, it is never reused.
    for (int i = 0; i < MAX_CHAN; i++) {
        int id = next_unused_chid_++;
        if (next_unused_chid_ == MAX_CHAN) next_unused_chid_ = 1;
        if (channels_[id] == nullptr) return id;
    }
    assert(false);
    return 0;
}

Channel *DrivenEngine::get_chid(int chid) {
    assert(unsigned(chid) < MAX_CHAN);
    assert(channels_[chid] != nullptr);
    return channels_[chid];
}

void DrivenEngine::listen_port(int port) {
    listen_ports_.insert(port);
}

double DrivenEngine::get_clock() {
    return clock_;
}

UniqueChannel DrivenEngine::new_outgoing_channel(const std::string &target) {
    int chid = find_unused_chid();
    new_outgoing_.insert(chid);
    return UniqueChannel(new Channel(this, chid, 0, target));
}

UniqueChannel DrivenEngine::new_incoming_channel() {
    if (accepted_channels_.empty()) {
        return nullptr;
    } else {
        UniqueChannel result = std::move(accepted_channels_.back());
        accepted_channels_.pop_back();
        return std::move(result);
    }
}

Channel *DrivenEngine::get_stdio_channel() {
    return stdio_channel_.get();
}

util::LuaSourcePtr DrivenEngine::get_lua_source() {
    return std::move(lua_source_);
}

void DrivenEngine::rescan_lua_source() {
    rescan_lua_source_ = true;
}

void DrivenEngine::stop_driver() {
    stop_driver_ = true;
}

void DrivenEngine::drv_get_listen_ports(std::set<int> &ports) {
    ports = listen_ports_;
}

void DrivenEngine::drv_get_new_closed(std::set<int> &channels) {
    channels = std::move(new_closed_);
    new_closed_.clear();
}

void DrivenEngine::drv_get_new_outgoing(std::set<int> &channels) {
    channels = std::move(new_outgoing_);
    new_outgoing_.clear();
}

const std::string &DrivenEngine::drv_get_target(int chid) {
    return get_chid(chid)->target_;
}

bool DrivenEngine::drv_outgoing_empty(int chid) {
    return get_chid(chid)->sb_out_->empty();
}

void DrivenEngine::drv_peek_outgoing(int chid, int *nbytes, const char **bytes) {
    return get_chid(chid)->peek_outgoing(nbytes, bytes);
}

void DrivenEngine::drv_sent_outgoing(int chid, int nbytes) {
    return get_chid(chid)->sent_outgoing(nbytes);
}

void DrivenEngine::drv_recv_incoming(int chid, int nbytes, const char *bytes) {
    if (nbytes > 0) {
        Channel *ch = get_chid(chid);
        if (ch->readline_enabled_) {
            ch->feed_readline(nbytes, bytes);
        } else {
            ch->sb_in_->write_bytes(bytes, nbytes);
        }
    }
}

void DrivenEngine::drv_notify_close(int chid, const std::string &err) {
    Channel *ch = get_chid(chid);
    ch->closed_ = true;
    ch->error_ = err;
}

int DrivenEngine::drv_notify_accept(int port) {
    int chid = find_unused_chid();
    accepted_channels_.emplace_back(new Channel(this, chid, port, ""));
    return chid;
}

void DrivenEngine::drv_set_clock(double t) {
    clock_ = t;
}

void DrivenEngine::drv_set_lua_source(util::LuaSourcePtr source) {
    lua_source_ = std::move(source);
    rescan_lua_source_ = false;
}

void DrivenEngine::drv_invoke_event_init(int argc, char *argv[]) {
    event_init(argc, argv);
}

void DrivenEngine::drv_invoke_event_update() {
    event_update();
}

bool DrivenEngine::drv_get_rescan_lua_source() {
    return rescan_lua_source_;
}

bool DrivenEngine::drv_get_stop_driver() {
    return stop_driver_;
}

DrivenEngine::DrivenEngine() {
    for (int i = 0; i < MAX_CHAN; i++) {
        channels_[i] = nullptr;
    }
    next_unused_chid_ = 1;
    stdio_channel_.reset(new Channel(this, 0, 0, ""));
    rescan_lua_source_ = true;
    clock_ = 0.0;
    stop_driver_ = false;
}

DrivenEngine::~DrivenEngine() {
    // Delete the channels that we own.
    stdio_channel_.reset();
    accepted_channels_.clear();
    // At this point, all channels should be gone.
    for (int i = 0; i < MAX_CHAN; i++) {
        assert(channels_[i] == nullptr);
    }
}

static DrivenEngine *engine_;

void DrivenEngine::set(DrivenEngine *de) {
    engine_ = de;
}

DrivenEngine *DrivenEngine::get() {
    return engine_;
}