#ifndef OPATIO_H
#define OPATIO_H

#include <iostream>
#include <fstream>
#include <string>
#include <vector>
#include <queue>

struct Header {
    char magic[4];
    uint16_t version;
    uint32_t numTables;
    uint32_t headerSize;
    uint64_t indexOffset;
    char creationDate[16];
    char sourceInfo[64];
    char comment[128];
    char reserved[26]; 
};

struct TableIndex {
    double X;
    double Z;
    // double C; // For type 2 OPAL tables. When not set will be 0
    // double O; // For type 2 OPAL tables. When not set will be 0
    uint64_t byteStart;
    uint64_t byteEnd;
    char sha256[32];
};

struct OPATTable {
    uint32_t N_R;
    uint32_t N_T;
    std::vector<double> logR;
    std::vector<double> logT;
    std::vector<std::vector<double>> logKappa;
};

class OpatIO {
private:
    Header header;
    std::vector<TableIndex> tableIndex;
    std::queue<OPATTable> tableQueue;
    int maxQDepth = 10;
    std::string filename;
    bool loaded = false;

    void readHeader(std::ifstream &file);
    void readTableIndex(std::ifstream &file);

    bool isTableInQueue(double X, double Z);
    OPATTable getTableFromQueue(double X, double Z);
    void addTableToQueue(OPATTable table);
    void removeTableFromQueue();

    void flushQueue();

    uint16_t getOPATVersion();

    uint16_t getTableID(double X, double Z);
    uint64_t getTableByteStart(uint16_t tableID);
    uint64_t getTableByteEnd(uint16_t tableID);

public:
    OpatIO();
    OpatIO(std::string filename);
    ~OpatIO();

    OPATTable getTable(double X, double, double C=0, double O=0);
    OPATTable getTable(uint16_t tableID);
    void setMaxQDepth(int depth);
    int getMaxQDepth();
    void setFilename(std::string filename);
    void load();
    void unload();
    bool isLoaded();

    void printHeader();
    void printTableIndex();
    void printTable(OPATTable table);

    std::vector<OPATTable> getTables();
    std::vector<TableIndex> getTableIndex();
    Header getHeader();

    std::vector<OPATTable> getClosestXTables(double X, double ZExact, double C=0, double O=0, int numTables=1);
    std::vector<OPATTable> getClosestZTables(double XExact, double Z, double C=0, double O=0, int numTables=1);
    std::vector<OPATTable> getClosestTables(double X, double Z, double C=0, double O=0, int numTables=1);  
};


#endif