/* Software License Agreement
 * 
 *     Copyright(C) 1994-2021 David Lindauer, (LADSoft)
 * 
 *     This file is part of the Orange C Compiler package.
 * 
 *     The Orange C Compiler package is free software: you can redistribute it and/or modify
 *     it under the terms of the GNU General Public License as published by
 *     the Free Software Foundation, either version 3 of the License, or
 *     (at your option) any later version.
 * 
 *     The Orange C Compiler package is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *     GNU General Public License for more details.
 * 
 *     You should have received a copy of the GNU General Public License
 *     along with Orange C.  If not, see <http://www.gnu.org/licenses/>.
 * 
 *     contact information:
 *         email: TouchStone222@runbox.com <David Lindauer>
 * 
 */

#include "ppCond.h"
#include "Errors.h"
#include "PreProcessor.h"
#include "ppkw.h"
#include "UTF8.h"
#include <cctype>

ppCond::~ppCond() {}
bool ppCond::Check(kw token, const std::string& line, int lineno)
{
    std::string line1 = line;
    switch (token)
    {
        case kw::ELSE:
            HandleElse(line1);
            break;
        case kw::ENDIF:
            HandleEndIf(line1);
            break;
        case kw::IF:
            define->replaceDefined(line1);
            define->Process(line1);
            HandleIf(current.get() && current.get()->skipping ? true : expr.Eval(line1, true), line1, lineno);
            break;
        case kw::ELIF:
            define->replaceDefined(line1);
            define->Process(line1);
            HandleElif(expr.Eval(line1, true), line1);
            break;
        case kw::IFDEF:
            HandleDef(line1, false, false, lineno);
            break;
        case kw::IFNDEF:
            HandleDef(line1, false, true, lineno);
            break;
        case kw::ELIFDEF:
            HandleDef(line1, true, false, lineno);
            break;
        case kw::ELIFNDEF:
            HandleDef(line1, true, true, lineno);
            break;
        case kw::IFIDN:
            HandleIdn(line1, false, false, true, lineno);
            break;
        case kw::ELIFIDN:
            HandleIdn(line1, true, false, true, lineno);
            break;
        case kw::IFNIDN:
            HandleIdn(line1, false, true, true, lineno);
            break;
        case kw::ELIFNIDN:
            HandleIdn(line1, true, true, true, lineno);
            break;
        case kw::IFIDNI:
            HandleIdn(line1, false, false, false, lineno);
            break;
        case kw::ELIFIDNI:
            HandleIdn(line1, true, false, false, lineno);
            break;
        case kw::IFNIDNI:
            HandleIdn(line1, false, true, false, lineno);
            break;
        case kw::ELIFNIDNI:
            HandleIdn(line1, true, true, false, lineno);
            break;
        case kw::IFID:
            HandleId(line1, false, false, lineno);
            break;
        case kw::ELIFID:
            HandleId(line1, true, false, lineno);
            break;
        case kw::IFNID:
            HandleId(line1, false, true, lineno);
            break;
        case kw::ELIFNID:
            HandleId(line1, true, true, lineno);
            break;
        case kw::IFNUM:
            HandleNum(line1, false, false, lineno);
            break;
        case kw::ELIFNUM:
            HandleNum(line1, true, false, lineno);
            break;
        case kw::IFNNUM:
            HandleNum(line1, false, true, lineno);
            break;
        case kw::ELIFNNUM:
            HandleNum(line1, true, true, lineno);
            break;
        case kw::IFSTR:
            HandleStr(line1, false, false, lineno);
            break;
        case kw::ELIFSTR:
            HandleStr(line1, true, false, lineno);
            break;
        case kw::IFNSTR:
            HandleStr(line1, false, true, lineno);
            break;
        case kw::ELIFNSTR:
            HandleStr(line1, true, true, lineno);
            break;
        case kw::IFCTX:
            HandleCtx(line1, false, false, lineno);
            break;
        case kw::ELIFCTX:
            HandleCtx(line1, true, false, lineno);
            break;
        case kw::IFNCTX:
            HandleCtx(line1, false, true, lineno);
            break;
        case kw::ELIFNCTX:
            HandleCtx(line1, true, true, lineno);
            break;
        default:
            return current && current->skipping;
    }
    return true;
}
void ppCond::HandleIf(bool val, const std::string& line, int lineno)
{
    skip* old = current.get();
    bool skipping = false;
    if (old)
        skipping = old->skipping;
    if (current)
        skipList.push_front(std::move(current));
    current = std::make_unique<skip>();
    current->line = lineno;
    if (skipping)
    {
        current->skipping = true;
    }
    else if (!val)
    {
        current->skipping = true;
        current->takeElse = true;
    }
}
void ppCond::HandleElif(bool val, const std::string& line)
{
    ansieol(line);
    if (!current || current->elseSeen)
    {
        Errors::Error("Misplaced elif directive");
    }
    else
    {
        skip* old = nullptr;
        if (!skipList.empty())
            old = skipList.front().get();
        if ((!old || !old->skipping) && current->takeElse && val)
        {
            current->skipping = false;
            current->takeElse = false;
        }
        else
        {
            current->skipping = true;
        }
    }
}
void ppCond::HandleElse(std::string& line)
{
    int npos = line.find_first_not_of(" \r\n\t\v");
    if (npos != std::string::npos)
    {
        std::string line1 = line;
        if (line1.substr(npos, 2) == "if")
        {
            line1 = line1.substr(npos + 2);
            define->replaceDefined(line1);
            define->Process(line1);
            HandleElif(expr.Eval(line1, true), line1);
            return;
        }
    }
    ansieol(line);
    if (!current)
    {
        Errors::Error("Misplaced else directive");
    }
    else
    {
        if (current->takeElse)
        {
            current->skipping = false;
        }
        else
        {
            current->skipping = true;
        }
        if (current->elseSeen)
        {
            Errors::Error("Misplaced else directive");
        }
        current->elseSeen = true;
    }
}
void ppCond::HandleEndIf(std::string& line)
{
    ansieol(line);
    if (!current)
    {
        Errors::Error("Misplaced endif directive");
    }
    else
    {
        if (!skipList.empty())
        {
            current = std::move(skipList.front());
            skipList.pop_front();
        }
        else
        {
            current = nullptr;
        }
    }
}
void ppCond::HandleDef(std::string& line, bool Else, bool negate, int lineno)
{
    Tokenizer tk(line, nullptr);
    const Token* t = tk.Next();
    if (!t->IsIdentifier())
    {
        Errors::Error("Identifier expected");
        if (Else)
            HandleElif(false, "");
        else
            HandleIf(false, "", lineno);
    }
    else
    {
        bool v = !!define->Lookup(t->GetId());
        if (asmpp && !v)
        {
            std::string one = UTF8::ToUpper(t->GetId());
            Symbol* t = define->Lookup(one);
            if (t)
            {
                ppDefine::Definition* p = static_cast<ppDefine::Definition*>(t);
                v = p->IsCaseInsensitive();
            }
        }
        if (negate)
            v = !v;
        if (Else)
            HandleElif(v, tk.GetString());
        else
            HandleIf(v, tk.GetString(), lineno);
    }
}
void ppCond::HandleIdn(std::string& line, bool Else, bool negate, bool caseSensitive, int lineno)
{
    define->Process(line);
    size_t n = line.find_first_of(',');
    if (n == std::string::npos)
    {
        Errors::Error("Syntax error in string comparison directive");
        if (Else)
            HandleElif(false, "");
        else
            HandleIf(false, "", lineno);
    }
    else
    {
        std::string line1 = line.substr(0, n);
        line.erase(0, n + 1);
        n = line.find_first_not_of(" \t\v\n");
        if (n && n != std::string::npos)
            line.erase(0, n);
        n = line.find_last_not_of(" \t\v\n");
        if (n != std::string::npos && n != line.size() - 1)
            line.erase(n + 1, line.size() - n - 1);
        n = line1.find_first_not_of(" \t\v\n");
        if (n && n != std::string::npos)
            line1.erase(0, n);
        n = line1.find_last_not_of(" \t\v\n");
        if (n != std::string::npos && n != line1.size() - 1)
            line1.erase(n + 1, line1.size() - n - 1);
        int pos = 0, pos1 = 0;
        int z = 0;
        if (!caseSensitive)
        {
            line = UTF8::ToUpper(line);
            line1 = UTF8::ToUpper(line);
        }
        while (true)
        {
            if (line[pos] == ' ' || line[pos] == '\t' || line[pos] == '\v' || line[pos] == '\n')
            {
                z ^= 1;
                pos = line.find_first_not_of(" \t\v\n", pos);
                if (pos == std::string::npos)
                    pos = line.size();
            }
            if (line1[pos1] == ' ' || line1[pos1] == '\t' || line1[pos1] == '\v' || line1[pos1] == '\n')
            {
                z ^= 1;
                pos1 = line1.find_first_not_of(" \t\v\n", pos);
                if (pos1 == std::string::npos)
                    pos1 = line1.size();
            }
            if (z || pos == line.size() || pos1 == line1.size())
                break;
            if (line[pos] != line1[pos1])
                break;
            pos++, pos1++;
            if (pos == line.size() || pos1 == line1.size())
                break;
        }
        bool v = !z && pos == line.size() && pos1 == line1.size();
        if (negate)
            v = !v;
        if (Else)
            HandleElif(v, "");
        else
            HandleIf(v, "", lineno);
    }
}
void ppCond::HandleId(std::string& line, bool Else, bool negate, int lineno)
{
    define->Process(line);
    Tokenizer tk(line, nullptr);
    const Token* t = tk.Next();
    bool v = t->IsIdentifier();
    if (negate)
        v = !v;
    if (Else)
        HandleElif(v, tk.GetString());
    else
        HandleIf(v, tk.GetString(), lineno);
}
void ppCond::HandleNum(std::string& line, bool Else, bool negate, int lineno)
{
    define->Process(line);
    Tokenizer tk(line, nullptr);
    const Token* t = tk.Next();
    bool v = t->IsNumeric();
    if (negate)
        v = !v;
    if (Else)
        HandleElif(v, tk.GetString());
    else
        HandleIf(v, tk.GetString(), lineno);
}
void ppCond::HandleStr(std::string& line, bool Else, bool negate, int lineno)
{
    define->Process(line);
    Tokenizer tk(line, nullptr);
    const Token* t = tk.Next();
    bool v = t->IsString();
    if (negate)
        v = !v;
    if (Else)
        HandleElif(v, tk.GetString());
    else
        HandleIf(v, tk.GetString(), lineno);
}
void ppCond::HandleCtx(std::string& line, bool Else, bool negate, int lineno)
{
    define->Process(line);
    Tokenizer tk(line, nullptr);
    const Token* t = tk.Next();
    bool v = false;
    if (t->IsIdentifier())
    {
        v = ctx->Matches(t->GetId());
        if (negate)
            v = !v;
    }
    else
    {
        Errors::Error("Identifier expected");
    }
    if (Else)
        HandleElif(v, tk.GetString());
    else
        HandleIf(v, tk.GetString(), lineno);
}
void ppCond::ansieol(const std::string& line)
{
    if (!extensions)
    {
        const char* p = line.c_str();
        while (*p)
        {
            if (!isspace(*p))
            {
                Errors::Error("Extra characters past end of preprocessor directive");
                break;
            }
            p++;
        }
    }
}
void ppCond::CheckErrors()
{
    if (!skipList.empty() || current)
    {
        Errors::Error("Non-terminated preprocessor conditional started in line " + Errors::ToNum(current->line));
    }
}
