/*
 * Copyright (C) 2004-2023 ZNC, see the NOTICE file for details.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <znc/Chan.h>
#include <znc/IRCNetwork.h>

using std::vector;

class CAutoCycleMod : public CModule {
  public:
    MODCONSTRUCTOR(CAutoCycleMod) {
        AddHelpCommand();
        AddCommand(
            "Add", t_d("[!]<#chan>"),
            t_d("Add an entry, use !#chan to negate and * for wildcards"),
            [=](const CString& sLine) { OnAddCommand(sLine); });
        AddCommand("Del", t_d("[!]<#chan>"),
                   t_d("Remove an entry, needs to be an exact match"),
                   [=](const CString& sLine) { OnDelCommand(sLine); });
        AddCommand("List", "", t_d("List all entries"),
                   [=](const CString& sLine) { OnListCommand(sLine); });
        m_recentlyCycled.SetTTL(15 * 1000);
    }

    ~CAutoCycleMod() override {}

    bool OnLoad(const CString& sArgs, CString& sMessage) override {
        VCString vsChans;
        sArgs.Split(" ", vsChans, false);

        for (const CString& sChan : vsChans) {
            if (!Add(sChan)) {
                PutModule(t_f("Unable to add {1}")(sChan));
            }
        }

        // Load our saved settings, ignore errors
        MCString::iterator it;
        for (it = BeginNV(); it != EndNV(); ++it) {
            Add(it->first);
        }

        // Default is auto cycle for all channels
        if (m_vsChans.empty()) Add("*");

        return true;
    }

    void OnAddCommand(const CString& sLine) {
        CString sChan = sLine.Token(1);

        if (AlreadyAdded(sChan)) {
            PutModule(t_f("{1} is already added")(sChan));
        } else if (Add(sChan)) {
            PutModule(t_f("Added {1} to list")(sChan));
        } else {
            PutModule(t_s("Usage: Add [!]<#chan>"));
        }
    }

    void OnDelCommand(const CString& sLine) {
        CString sChan = sLine.Token(1);

        if (Del(sChan))
            PutModule(t_f("Removed {1} from list")(sChan));
        else
            PutModule(t_s("Usage: Del [!]<#chan>"));
    }

    void OnListCommand(const CString& sLine) {
        CTable Table;
        Table.AddColumn(t_s("Channel"));
        Table.SetStyle(CTable::ListStyle);

        for (const CString& sChan : m_vsChans) {
            Table.AddRow();
            Table.SetCell(t_s("Channel"), sChan);
        }

        for (const CString& sChan : m_vsNegChans) {
            Table.AddRow();
            Table.SetCell(t_s("Channel"), "!" + sChan);
        }

        if (Table.size()) {
            PutModule(Table);
        } else {
            PutModule(t_s("You have no entries."));
        }
    }

    void OnPart(const CNick& Nick, CChan& Channel,
                const CString& sMessage) override {
        AutoCycle(Channel);
    }

    void OnQuit(const CNick& Nick, const CString& sMessage,
                const vector<CChan*>& vChans) override {
        for (CChan* pChan : vChans) AutoCycle(*pChan);
    }

    void OnKick(const CNick& Nick, const CString& sOpNick, CChan& Channel,
                const CString& sMessage) override {
        AutoCycle(Channel);
    }

  protected:
    void AutoCycle(CChan& Channel) {
        if (!IsAutoCycle(Channel.GetName())) return;

        // Did we recently annoy opers via cycling of an empty channel?
        if (m_recentlyCycled.HasItem(Channel.GetName())) return;

        // Is there only one person left in the channel?
        if (Channel.GetNickCount() != 1) return;

        // Is that person us and we don't have op?
        const CNick& pNick = Channel.GetNicks().begin()->second;
        if (!pNick.HasPerm(CChan::Op) &&
            pNick.NickEquals(GetNetwork()->GetCurNick())) {
            Channel.Cycle();
            m_recentlyCycled.AddItem(Channel.GetName());
        }
    }

    bool AlreadyAdded(const CString& sInput) {
        CString sChan = sInput;
        if (sChan.TrimPrefix("!")) {
            for (const CString& s : m_vsNegChans) {
                if (s.Equals(sChan)) return true;
            }
        } else {
            for (const CString& s : m_vsChans) {
                if (s.Equals(sChan)) return true;
            }
        }
        return false;
    }

    bool Add(const CString& sChan) {
        if (sChan.empty() || sChan == "!") {
            return false;
        }

        if (sChan.Left(1) == "!") {
            m_vsNegChans.push_back(sChan.substr(1));
        } else {
            m_vsChans.push_back(sChan);
        }

        // Also save it for next module load
        SetNV(sChan, "");

        return true;
    }

    bool Del(const CString& sChan) {
        vector<CString>::iterator it, end;

        if (sChan.empty() || sChan == "!") return false;

        if (sChan.Left(1) == "!") {
            CString sTmp = sChan.substr(1);
            it = m_vsNegChans.begin();
            end = m_vsNegChans.end();

            for (; it != end; ++it)
                if (*it == sTmp) break;

            if (it == end) return false;

            m_vsNegChans.erase(it);
        } else {
            it = m_vsChans.begin();
            end = m_vsChans.end();

            for (; it != end; ++it)
                if (*it == sChan) break;

            if (it == end) return false;

            m_vsChans.erase(it);
        }

        DelNV(sChan);

        return true;
    }

    bool IsAutoCycle(const CString& sChan) {
        for (const CString& s : m_vsNegChans) {
            if (sChan.WildCmp(s, CString::CaseInsensitive)) {
                return false;
            }
        }

        for (const CString& s : m_vsChans) {
            if (sChan.WildCmp(s, CString::CaseInsensitive)) {
                return true;
            }
        }

        return false;
    }

  private:
    vector<CString> m_vsChans;
    vector<CString> m_vsNegChans;
    TCacheMap<CString> m_recentlyCycled;
};

template <>
void TModInfo<CAutoCycleMod>(CModInfo& Info) {
    Info.SetWikiPage("autocycle");
    Info.SetHasArgs(true);
    Info.SetArgsHelpText(Info.t_s(
        "List of channel masks and channel masks with ! before them."));
}

NETWORKMODULEDEFS(
    CAutoCycleMod,
    t_s("Rejoins channels to gain Op if you're the only user left"))
