// Copyright(c) 2015-2017 YamaArashi
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#include <cstdio>
#include <string>
#include "scaninc.h"
#include "asm_file.h"

AsmFile::AsmFile(std::string path) {
    m_path = path;

    FILE* fp = std::fopen(path.c_str(), "rb");

    if (fp == NULL)
        fatal_error("Failed to open \"%s\" for reading.\n", path.c_str());

    std::fseek(fp, 0, SEEK_END);

    m_size = static_cast<size_t>(std::ftell(fp));

    m_buffer = new char[m_size];

    std::rewind(fp);

    if (std::fread(m_buffer, m_size, 1, fp) != 1)
        fatal_error("Failed to read \"%s\".\n", path.c_str());

    std::fclose(fp);

    m_pos = 0;
    m_lineNum = 1;
}

AsmFile::~AsmFile() {
    delete[] m_buffer;
}

IncDirectiveType AsmFile::ReadUntilIncDirective(std::string& path) {
    // At the beginning of each loop iteration, the current file position
    // should be at the start of a line or at the end of the file.
    for (;;) {
        SkipTabsAndSpaces();

        IncDirectiveType incDirectiveType = IncDirectiveType::None;

        if (char c = static_cast<char>(PeekChar()); c == '.' || c == '#') {
            m_pos++;

            if (MatchIncDirective("incbin", path))
                incDirectiveType = IncDirectiveType::Incbin;
            else if (MatchIncDirective("include", path))
                incDirectiveType = IncDirectiveType::Include;
        }

        for (;;) {
            int c = GetChar();

            if (c == -1)
                return incDirectiveType;

            if (c == ';') {
                SkipEndOfLineComment();
                break;
            } else if (c == '/' && PeekChar() == '*') {
                m_pos++;
                SkipMultiLineComment();
            } else if (c == '"') {
                SkipString();
            } else if (c == '\n') {
                break;
            }
        }

        if (incDirectiveType != IncDirectiveType::None)
            return incDirectiveType;
    }
}

std::string AsmFile::ReadPath() {
    size_t length = 0;
    size_t startPos = m_pos;

    for (;;) {
        int c = GetChar();

        if (c == '"')
            break;

        if (c == -1)
            fatal_error(INPUT_ERROR_MESSAGE("unexpected EOF in include string\n"));

        if (c == 0)
            fatal_error(INPUT_ERROR_MESSAGE("unexpected NUL character in include string\n"));

        if (c == '\n')
            fatal_error(INPUT_ERROR_MESSAGE("unexpected end of line character in include string\n"));

        // Don't bother allowing any escape sequences.
        if (c == '\\')
            fatal_error(INPUT_ERROR_MESSAGE("unexpected escape in include string\n"));

        length++;

        if (length > SCANINC_MAX_PATH)
            fatal_error(INPUT_ERROR_MESSAGE("path is too long"));
    }

    return std::string(m_buffer + startPos, length);
}

void AsmFile::SkipEndOfLineComment() {
    int c;

    do {
        c = GetChar();
    } while (c != -1 && c != '\n');
}

void AsmFile::SkipMultiLineComment() {
    for (;;) {
        int c = GetChar();

        if (c == '*') {
            if (PeekChar() == '/') {
                m_pos++;
                return;
            }
        } else if (c == -1) {
            return;
        }
    }
}

void AsmFile::SkipString() {
    for (;;) {
        int c = GetChar();

        if (c == '"')
            break;

        if (c == -1)
            fatal_error(INPUT_ERROR_MESSAGE("unexpected EOF in string\n"));

        if (c == '\\') {
                c = GetChar();
        }
    }
}
