/*
 * GPS Test Tool - PC Application
 *
 * Tests GPS filtering and GPX generation using actual embedded code
 * Usage: ./gps-test-tool <input.nmea>
 *
 * Generates:
 *   - output_filtered.gpx
 *   - output_unfiltered.gpx
 *   - debug_filtered.txt
 *   - debug_unfiltered.txt
 */

#define PC_BUILD
#include "main.h"

/* Global variables expected by project code */
volatile struct system_s System;
struct location_s location;
time_t utc;
unsigned char config_flags = 0;
unsigned char FLAGS = 0;
volatile unsigned char reset_cause = 0; /* no real MCU reset happened; log_boot_record() reports "UNKNOWN" */

/* File handle for debug output redirection */
FILE *debug_output = NULL;

/* soft/syslog.c's log_config()/log_boot_record() print these; not part of
 * this PC build otherwise (they're normally in soft/settings.c). */
__flash const char gnss_name_stub[] = "GPS+GLONASS+GALILEO/etc (PC test tool - not tracked per mode)";
__flash const char *gnss_names[] = {
	gnss_name_stub, gnss_name_stub, gnss_name_stub,
	gnss_name_stub, gnss_name_stub, gnss_name_stub,
};
__flash const char uart_log_mode_stub[] = "n/a (PC test tool)";
__flash const char *uart_log_mode_names[] = {
	uart_log_mode_stub, uart_log_mode_stub, uart_log_mode_stub,
};

/* Function prototypes from project files */
unsigned char gpx_init(FIL *file);
unsigned char gpx_close(FIL *file);
void gpx_process_point(struct location_s *loc, FIL *file);
time_t gps_parse(const char *nmea);

/* Time function implementation */
char *get_iso_time(time_t time, unsigned char local) {
    static char output[32];
    struct tm *ct = gmtime(&time);
    sprintf(output, "%04d-%02d-%02dT%02d:%02d:%02d.000Z",
            ct->tm_year + 1900, ct->tm_mon + 1, ct->tm_mday,
            ct->tm_hour, ct->tm_min, ct->tm_sec);
    return output;
}

void iso_time_to_filename(char *time) {
    while (*time) {
        switch (*time) {
            case ':': *time = '-'; break;
            case '+': *time = 'p'; break;
        }
        time++;
    }
}

/* Reset system state */
void reset_system(void) {
    memset((void*)&System, 0, sizeof(System));
    memset(&location, 0, sizeof(location));
    System.conf.skip_points = 0;  /* Don't skip points for testing */
    /* Match soft/settings.c's defaults_u8, so this tool's auto-pause behavior
     * (enabled below) matches an out-of-the-box device. */
    System.conf.auto_pause_time = 30;
    System.conf.auto_pause_dist = 10;
    System.conf.auto_pause_speed = 3;
    System.conf.min_sats = 4;  /* Require at least 4 satellites */
    System.tracking_paused = 0;
    System.tracking_auto_paused = 0;
    System.bat_volt = 4.0f;   /* no real ADC here; keeps the status line's v=/bat%= fields sane */
    System.bat_volt_min = 4.0f;
    utc = 0;
}

/* Process NMEA file with specified filter setting */
int process_nmea_file(const char *input_file, const char *output_gpx,
                      const char *debug_file, int filters_enabled) {
    FILE *input;
    FIL gpx_file;
    char line[256];
    int point_count = 0;

    /* Open input file */
    input = fopen(input_file, "r");
    if (!input) {
        fprintf(stderr, "Error: Cannot open input file '%s'\n", input_file);
        return 1;
    }

    /* Open debug output file */
    debug_output = fopen(debug_file, "w");
    if (!debug_output) {
        fprintf(stderr, "Error: Cannot open debug file '%s'\n", debug_file);
        fclose(input);
        return 1;
    }

    /* Configure filters */
    config_flags = (filters_enabled ? 0 : CONFFLAG_DISABLE_FILTERS) | CONFFLAG_AUTO_PAUSE;

    /* Reset system state */
    reset_system();
    gps_powered_on();
    log_boot_record();

    /* Open GPX output file */
    if (f_open(&gpx_file, output_gpx, FA_WRITE | FA_OPEN_ALWAYS) != 0) {
        fprintf(stderr, "Error: Cannot open GPX file '%s'\n", output_gpx);
        fclose(input);
        fclose(debug_output);
        return 1;
    }

    /* Initialize GPX file */
    if (gpx_init(&gpx_file) != 0) {
        fprintf(stderr, "Error: GPX initialization failed\n");
        fclose(input);
        fclose(debug_output);
        f_close(&gpx_file);
        return 1;
    }

    fprintf(debug_output, "=== GPS Test Tool - %s ===\n",
            filters_enabled ? "FILTERS ENABLED" : "FILTERS DISABLED");
    fprintf(debug_output, "Input: %s\n", input_file);
    fprintf(debug_output, "Output: %s\n\n", output_gpx);

    /* Process NMEA file line by line */
    /* Kept in sync with soft/main.c's FIX_HOLD_EPOCHS. */
    #define FIX_HOLD_EPOCHS 5
    unsigned char fix_ok_prev = 0;
    unsigned char fix_hold_counter = 0;
    unsigned char sbas_prev = 0xFF; /* 0xFF: not yet known, suppress the first (non-)transition */
    time_t next_status_utc = 0;
    time_t next_summary_utc = 0;
    while (fgets(line, sizeof(line), input)) {
        size_t len = strlen(line);

        /* Skip empty lines */
        if (len == 0) continue;

        /* Ensure line ends with \r\n as expected by gps_parse */
        if (len > 0 && line[len-1] == '\n') {
            line[len-1] = '\0';
            len--;
        }
        if (len > 0 && line[len-1] == '\r') {
            line[len-1] = '\0';
            len--;
        }
        /* Add back \r\n for gps_parse */
        strcat(line, "\r\n");

        /* Parse NMEA sentence */
        if (gps_parse(line) != 0) {
            /* Valid location data received (RMC parsed) */
            /* Only process if we have valid coordinates from GGA */
            if (System.location_valid == LOC_VALID_NEW || System.location_valid == LOC_VALID) {
                gpx_process_point(&location, &gpx_file);
                auto_pause_process();
                point_count++;
            }
        }

        /* Mirror soft/main.c's system-log event/status triggers, so this
         * tool exercises and lets you review the same log output the
         * firmware produces. There's no real clock here, so pace the
         * periodic status line/session summary off the NMEA timestamps
         * instead of uptime. */
        if (utc) {
            if (nmea_epoch_complete()) {
                unsigned char fix_ok_now = (FLAGS & F_GPSOK) && !System.sat_count_low;
                if (fix_ok_now == fix_ok_prev) {
                    fix_hold_counter = 0;
                } else if (++fix_hold_counter >= FIX_HOLD_EPOCHS) {
                    fix_hold_counter = 0;
                    fix_ok_prev = fix_ok_now;
                    if (fix_ok_now)
                        log_fix_event();
                    else
                        log_fix_lost();
                }
            }
            if (System.sbas != sbas_prev) {
                if (sbas_prev != 0xFF)
                    log_sbas_transition();
                sbas_prev = System.sbas;
            }
            if (!next_status_utc)
                next_status_utc = utc + 60;
            if (utc >= next_status_utc) {
                log_status_line();
                next_status_utc = utc + 60;
            }
            if (!next_summary_utc)
                next_summary_utc = utc + 3600;
            if (utc >= next_summary_utc) {
                log_session_summary(0);
                next_summary_utc = utc + 3600;
            }
        }
    }

    /* Close GPX file */
    gpx_close(&gpx_file);
    log_session_summary(1);

    /* Print summary */
    fprintf(debug_output, "\n=== Summary ===\n");
    fprintf(debug_output, "Points processed: %d\n", point_count);
    fprintf(debug_output, "Total distance: %.2f km\n", System.distance / 100000.0);
    fprintf(debug_output, "Elevation gain: %.1f m\n", System.elevation_gain / 10.0);
    fprintf(debug_output, "Elevation loss: %.1f m\n", System.elevation_loss / 10.0);

    /* Close files */
    fclose(input);
    fclose(debug_output);
    debug_output = NULL;

    printf("Processed %d points -> %s (filters %s)\n",
           point_count, output_gpx, filters_enabled ? "ON" : "OFF");

    return 0;
}

int main(int argc, char *argv[]) {
    int ret;

    printf("GPS Test Tool v1.0\n");
    printf("==================\n\n");

    if (argc != 2) {
        fprintf(stderr, "Usage: %s <input.nmea>\n", argv[0]);
        fprintf(stderr, "\nGenerates:\n");
        fprintf(stderr, "  - output_filtered.gpx\n");
        fprintf(stderr, "  - output_unfiltered.gpx\n");
        fprintf(stderr, "  - debug_filtered.txt\n");
        fprintf(stderr, "  - debug_unfiltered.txt\n");
        return 1;
    }

    /* Process with filters enabled */
    printf("Processing with filters ENABLED...\n");
    ret = process_nmea_file(argv[1], "output_filtered.gpx",
                            "debug_filtered.txt", 1);
    if (ret != 0) {
        fprintf(stderr, "Failed to process with filters enabled\n");
        return ret;
    }

    /* Process with filters disabled */
    printf("Processing with filters DISABLED...\n");
    ret = process_nmea_file(argv[1], "output_unfiltered.gpx",
                            "debug_unfiltered.txt", 0);
    if (ret != 0) {
        fprintf(stderr, "Failed to process with filters disabled\n");
        return ret;
    }

    printf("\nProcessing complete!\n");
    printf("Generated files:\n");
    printf("  - output_filtered.gpx (filters ON)\n");
    printf("  - output_unfiltered.gpx (filters OFF)\n");
    printf("  - debug_filtered.txt (debug output with filters)\n");
    printf("  - debug_unfiltered.txt (debug output without filters)\n");

    return 0;
}