/**
 * A user-space application linking to the CPER-JSON conversion library which allows for easy
 * conversion between CPER and CPER-JSON formats. 
 * 
 * Author: Lawrence.Tang@arm.com
 **/

#include <stdio.h>
#include <string.h>
#include <libgen.h>
#include <limits.h>
#include "json.h"
#include "../cper-parse.h"
#include "../json-schema.h"

void cper_to_json(int argc, char* argv[]);
void json_to_cper(int argc, char* argv[]);
void print_help(void);

int main(int argc, char* argv[]) 
{
    //Ensure at least one argument is present.
    if (argc < 2)
    {
        printf("Invalid number of arguments. See 'cper-convert --help' for command information.\n");
        return -1;
    }

    //Run the requested command.
    if (strcmp(argv[1], "to-json") == 0)
        cper_to_json(argc, argv);
    else if (strcmp(argv[1], "to-cper") == 0)
        json_to_cper(argc, argv);
    else if (strcmp(argv[1], "--help") == 0)
        print_help();
    else 
    {
        printf("Unrecognised argument '%s'. See 'cper-convert --help' for command information.\n", argv[1]);
        return -1;
    }

    return 0;
}

//Command for converting a provided CPER log file into JSON.
void cper_to_json(int argc, char* argv[])
{
    if (argc < 3)
    {
        printf("Insufficient number of arguments for 'to-json'. See 'cper-convert --help' for command information.\n");
        return;
    }

    //Get a handle for the log file.
    FILE* cper_file = fopen(argv[2], "r");
    if (cper_file == NULL) 
    {
        printf("Could not open provided CPER file '%s', file handle returned null.\n", argv[2]);
        return;
    }

    //Convert.
    json_object* ir = cper_to_ir(cper_file);
    fclose(cper_file);
    const char* json_output = json_object_to_json_string_ext(ir, JSON_C_TO_STRING_PRETTY);

    //Check whether there is a "--out" argument, if there is, then output to file instead.
    //Otherwise, just send to console.
    if (argc != 5)
    {
        printf("%s\n", json_output);
        return;
    }

    //File out argument exists. Argument valid?
    if (strcmp(argv[3], "--out") != 0)
    {
        printf("Invalid argument '%s' for command 'to-json'. See 'cper-convert --help' for command information.\n", argv[3]);
        return;
    }

    //Try to open a file handle to the desired output file.
    FILE* json_file = fopen(argv[4], "w");
    if (json_file == NULL) 
    {
        printf("Could not get a handle for output file '%s', file handle returned null.\n", argv[4]);
        return;
    }

    //Write out to file.
    fwrite(json_output, strlen(json_output), 1, json_file);
    fclose(json_file);
}

//Command for converting a provided CPER-JSON JSON file to CPER binary.
void json_to_cper(int argc, char* argv[])
{
    if (argc < 5)
    {
        printf("Insufficient number of arguments for 'to-cper'. See 'cper-convert --help' for command information.\n");
        return;
    }

    //Read JSON IR from file.
    json_object* ir = json_object_from_file(argv[2]);
    if (ir == NULL)
    {
        printf("Could not read JSON from file '%s', import returned null.\n", argv[2]);
        return;
    }

    //Are we skipping validation?
    int do_validate = 1;
    if (argc == 6)
    {
        if (strcmp(argv[5], "--no-validate") == 0)
        {
            do_validate = 0;
        }
        else
        {
            printf("Invalid argument '%s' for command 'to-cper'. See 'cper-convert --help' for command information.\n", argv[5]);
            return;
        }
    }

    //Validate the JSON against specification, unless otherwise specified.
    if (do_validate)
    {
        char* specification_path = NULL;

        //If there is another argument pair, it must be a validation specification file path.
        if (argc == 7)
        {
            //Ensure valid argument naming.
            if (strcmp(argv[5], "--specification") != 0)
            {
                printf("Invalid argument '%s' for command 'to-cper'. See 'cper-convert --help' for command information.\n", argv[5]);
                return;
            }

            specification_path = argv[6];
        }
        else if (argc == 5)
        {
            //Make the specification path the assumed default (application directory + specification/cper-json.json).
            specification_path = malloc(PATH_MAX);
            char* dir = dirname(argv[0]);
            strcpy(specification_path, dir);
            strcat(specification_path, "/specification/cper-json.json");
        }
        else
        {
            //Invalid number of arguments.
            printf("Invalid number of arguments for command 'to-cper'. See 'cper-convert --help' for command information.\n");
            return;
        }

        //Attempt to verify with the the specification.
        char* error_message = malloc(JSON_ERROR_MSG_MAX_LEN);
        int success = validate_schema_from_file(specification_path, ir, error_message);

        //Free specification path (if necessary).
        if (argc == 5)
            free(specification_path);

        //If failed, early exit before conversion.
        if (!success)
        {
            printf("JSON format validation failed: %s\n", error_message);
            free(error_message);
            return;
        }
        free(error_message);
    }

    //Attempt a conversion.
    //Open a read for the output file.
    FILE* cper_file = fopen(argv[4], "w");
    if (cper_file == NULL) 
    {
        printf("Could not open output file '%s', file handle returned null.\n", argv[4]);
        return;
    }

    //Run the converter.
    ir_to_cper(ir, cper_file);
    fclose(cper_file);
}

//Command for printing help information.
void print_help(void)
{
    printf(":: to-json cper.file [--out file.name]\n");
    printf("\tConverts the provided CPER log file into JSON, by default outputting to console. If '--out' is specified,\n");
    printf("\tThe outputted JSON will be written to the provided file name instead.\n");
    printf("\n:: to-cper cper.json --out file.name [--no-validate] [--specification some/spec/path.json]\n");
    printf("\tConverts the provided CPER-JSON JSON file into CPER binary. An output file must be specified with '--out'.\n");
    printf("\tBy default, the provided JSON will try to be validated against a specification. If no specification file path\n");
    printf("\tis provided with '--specification', then it will default to 'argv[0] + /specification/cper-json.json'.\n");
    printf("\tIf the '--no-validate' argument is set, then the provided JSON will not be validated. Be warned, this may cause\n");
    printf("\tpremature exit/unexpected behaviour in CPER output.\n");
    printf("\n:: --help\n");
    printf("\tDisplays help information to the console.\n");
}