/**
 * Runtime debug configuration implementation
 */

#define _GNU_SOURCE  // For strdup
#include "debug_config.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdarg.h>
#include <time.h>
#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>
#include <sys/stat.h>
FILE* debug_output_file = NULL;

/* Global debug configuration */
debug_config_t g_debug_config = {
    .level = DEBUG_LEVEL_ERROR,           // Default: errors only
    .categories = DEBUG_CATEGORY_ALL,     // All categories enabled
    .timestamp_enabled = 0,               // No timestamps by default
    .function_name_enabled = 0,           // No function names by default
    .file_line_enabled = 0,               // No file:line by default
    .color_enabled = 0,                   // No colors by default
    .max_output_per_second = 0,           // No rate limiting
    .output_file = NULL                   // Output to stderr
};

/* Rate limiting state */
static struct {
    size_t output_count;
    time_t last_reset_time;
    pthread_mutex_t mutex;
} rate_limit_state = {
    .output_count = 0,
    .last_reset_time = 0,
    .mutex = PTHREAD_MUTEX_INITIALIZER
};

/* Configuration file support */

/* ANSI color codes */
#define COLOR_RESET   "\033[0m"
#define COLOR_RED     "\033[31m"
#define COLOR_GREEN   "\033[32m"
#define COLOR_YELLOW  "\033[33m"
#define COLOR_BLUE    "\033[34m"
#define COLOR_MAGENTA "\033[35m"
#define COLOR_CYAN    "\033[36m"
#define COLOR_WHITE   "\033[37m"

/* Level color mapping */
static const char* level_colors[] = {
    [DEBUG_LEVEL_NONE]   = COLOR_RESET,
    [DEBUG_LEVEL_ERROR]  = COLOR_RED,
    [DEBUG_LEVEL_WARN]   = COLOR_YELLOW,
    [DEBUG_LEVEL_INFO]   = COLOR_GREEN,
    [DEBUG_LEVEL_DEBUG]  = COLOR_BLUE,
    [DEBUG_LEVEL_TRACE]  = COLOR_CYAN
};

/* Level name mapping */
static const char* level_names[] = {
    [DEBUG_LEVEL_NONE]   = "NONE",
    [DEBUG_LEVEL_ERROR]  = "ERROR",
    [DEBUG_LEVEL_WARN]   = "WARN",
    [DEBUG_LEVEL_INFO]   = "INFO",
    [DEBUG_LEVEL_DEBUG]  = "DEBUG",
    [DEBUG_LEVEL_TRACE]  = "TRACE"
};

/* Category name mapping */
static struct {
    debug_category_t category;
    const char* name;
} category_names[] = {
    { DEBUG_CATEGORY_UASYNC,     "uasync" },
    { DEBUG_CATEGORY_LL_QUEUE,   "ll_queue" },
    { DEBUG_CATEGORY_CONNECTION, "connection" },
    { DEBUG_CATEGORY_ETCP,       "etcp" },
    { DEBUG_CATEGORY_CRYPTO,     "crypto" },
    { DEBUG_CATEGORY_MEMORY,     "memory" },
    { DEBUG_CATEGORY_TIMING,     "timing" },
};

/* Initialize debug system with default settings */
void debug_config_init(void) {
    // Configuration is already initialized with defaults
    // This function is for API compatibility
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug system initialized with level %d", g_debug_config.level);
}

/* Set debug level */
void debug_set_level(debug_level_t level) {
    if (level < DEBUG_LEVEL_NONE || level > DEBUG_LEVEL_TRACE) {
        DEBUG_WARN(DEBUG_CATEGORY_MEMORY, "Invalid debug level: %d", level);
        return;
    }
    g_debug_config.level = level;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug level set to %s", level_names[level]);
}

/* Enable specific category */
void debug_enable_category(debug_category_t category) {
    g_debug_config.categories |= category;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug category enabled: 0x%x", category);
}

/* Disable specific category */
void debug_disable_category(debug_category_t category) {
    g_debug_config.categories &= ~category;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug category disabled: 0x%x", category);
}

/* Set all categories at once */
void debug_set_categories(uint32_t categories) {
    g_debug_config.categories = categories;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug categories set to: 0x%x", categories);
}

/* Configure output options */
void debug_enable_timestamp(int enable) {
    g_debug_config.timestamp_enabled = enable ? 1 : 0;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug timestamps %s", enable ? "enabled" : "disabled");
}

void debug_enable_function_name(int enable) {
    g_debug_config.function_name_enabled = enable ? 1 : 0;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug function names %s", enable ? "enabled" : "disabled");
}

void debug_enable_file_line(int enable) {
    g_debug_config.file_line_enabled = enable ? 1 : 0;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug file:line info %s", enable ? "enabled" : "disabled");
}

void debug_enable_color(int enable) {
    g_debug_config.color_enabled = enable ? 1 : 0;
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug colors %s", enable ? "enabled" : "disabled");
}

void debug_set_rate_limit(size_t max_per_second) {
    pthread_mutex_lock(&rate_limit_state.mutex);
    g_debug_config.max_output_per_second = max_per_second;
    rate_limit_state.output_count = 0;
    rate_limit_state.last_reset_time = 0;  // Force reset on next check
    pthread_mutex_unlock(&rate_limit_state.mutex);
    DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug rate limit set to %zu per second", max_per_second);
}

void debug_set_output_file(const char* file_path) {
    // Close existing file if open
    if (debug_output_file && debug_output_file != stderr) {
        fclose(debug_output_file);
        debug_output_file = NULL;
    }
    
    if (file_path) {
        debug_output_file = fopen(file_path, "a");
        if (!debug_output_file) {
            DEBUG_ERROR(DEBUG_CATEGORY_MEMORY, "Failed to open debug output file: %s", file_path);
            debug_output_file = stderr;
        } else {
            g_debug_config.output_file = file_path;
            DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug output redirected to file: %s", file_path);
        }
    } else {
        debug_output_file = stderr;
        g_debug_config.output_file = NULL;
        DEBUG_INFO(DEBUG_CATEGORY_MEMORY, "Debug output redirected to stderr");
    }
}

/* Check if debug output should be shown */
int debug_should_output(debug_level_t level, debug_category_t category) {
    // ERROR level always outputs as fallback, regardless of settings
    if (level == DEBUG_LEVEL_ERROR) {
        return 1;
    }
    
    // Check if this category is enabled
    if (!(g_debug_config.categories & category)) {
        return 0;
    }
    
    // Check if this level is enabled
    debug_level_t effective_level = debug_get_effective_level(category);
    if (level > effective_level) {
        return 0;
    }
    
    // Check rate limiting
    if (g_debug_config.max_output_per_second > 0) {
        pthread_mutex_lock(&rate_limit_state.mutex);
        time_t current_time = time(NULL);
        
        // Reset counter if a second has passed or if last_reset_time is 0 (initial state)
        if (rate_limit_state.last_reset_time == 0 || current_time != rate_limit_state.last_reset_time) {
            rate_limit_state.output_count = 0;
            rate_limit_state.last_reset_time = current_time;
        }
        
        // For testing: if we haven't exceeded the limit, allow it
        if (rate_limit_state.output_count < g_debug_config.max_output_per_second) {
            rate_limit_state.output_count++;
            pthread_mutex_unlock(&rate_limit_state.mutex);
            return 1;
        }
        
        pthread_mutex_unlock(&rate_limit_state.mutex);
        return 0;
    }
    
    return 1;
}

/* Get current debug level for a category */
debug_level_t debug_get_effective_level(debug_category_t category) {
    // For now, return global level (can be extended per-category in future)
    (void)category; // Unused parameter
    return g_debug_config.level;
}

/* Format and output debug message */
void debug_output(debug_level_t level, debug_category_t category,
                 const char* function, const char* file, int line,
                 const char* format, ...) {
    if (!debug_should_output(level, category)) {
        return;
    }
    
    FILE* output = debug_output_file ? debug_output_file : stderr;
    va_list args;
    
    // Get current time for timestamp
    struct timeval tv;
    gettimeofday(&tv, NULL);
    struct tm* tm_info = localtime(&tv.tv_sec);
    
    // Print timestamp if enabled
    if (g_debug_config.timestamp_enabled) {
        if (g_debug_config.color_enabled) {
            fprintf(output, "[%02d:%02d:%02d.%03ld] ",
                    tm_info->tm_hour, tm_info->tm_min, tm_info->tm_sec, tv.tv_usec / 1000);
        } else {
            fprintf(output, "[%02d:%02d:%02d.%03ld] ",
                    tm_info->tm_hour, tm_info->tm_min, tm_info->tm_sec, tv.tv_usec / 1000);
        }
    }
    
    // Print level with color
    if (g_debug_config.color_enabled) {
        fprintf(output, "%s[%s]%s ", level_colors[level], level_names[level], COLOR_RESET);
    } else {
        fprintf(output, "[%s] ", level_names[level]);
    }
    
    // Print category
    const char* category_name = "unknown";
    for (size_t i = 0; i < sizeof(category_names) / sizeof(category_names[0]); i++) {
        if (category_names[i].category == category) {
            category_name = category_names[i].name;
            break;
        }
    }
    fprintf(output, "[%s] ", category_name);
    
    // Print file:line if enabled
    if (g_debug_config.file_line_enabled) {
        fprintf(output, "%s:%d: ", file, line);
    }
    
    // Print function name if enabled
    if (g_debug_config.function_name_enabled) {
        fprintf(output, "%s(): ", function);
    }
    
    // Print the actual message
    va_start(args, format);
    vfprintf(output, format, args);
    va_end(args);
    
    fprintf(output, "\n");
    fflush(output);
}

/* Parse debug configuration from string */
int debug_parse_config(const char* config_string) {
    if (!config_string) return -1;
    
    // Handle simple level format directly
    if (strchr(config_string, ':') == NULL) {
        debug_level_t level = DEBUG_LEVEL_NONE;
        if (strcasecmp(config_string, "none") == 0) level = DEBUG_LEVEL_NONE;
        else if (strcasecmp(config_string, "error") == 0) level = DEBUG_LEVEL_ERROR;
        else if (strcasecmp(config_string, "warn") == 0) level = DEBUG_LEVEL_WARN;
        else if (strcasecmp(config_string, "info") == 0) level = DEBUG_LEVEL_INFO;
        else if (strcasecmp(config_string, "debug") == 0) level = DEBUG_LEVEL_DEBUG;
        else if (strcasecmp(config_string, "trace") == 0) level = DEBUG_LEVEL_TRACE;
        else {
            DEBUG_WARN(DEBUG_CATEGORY_MEMORY, "Invalid debug level: %s", config_string);
            return -1;
        }
        
        debug_set_level(level);
        debug_set_categories(DEBUG_CATEGORY_ALL);
        return 0;
    }
    
    // Handle category:level format
    char* config_copy = strdup(config_string);
    if (!config_copy) return -1;
    
    char* token = strtok(config_copy, ",");
    int errors = 0;
    
    while (token) {
        // Trim whitespace
        while (*token == ' ' || *token == '\t') token++;
        char* end = token + strlen(token) - 1;
        while (end > token && (*end == ' ' || *end == '\t')) end--;
        *(end + 1) = '\0';
        
        // Parse category:level format
        char* colon = strchr(token, ':');
        if (!colon) {
            DEBUG_WARN(DEBUG_CATEGORY_MEMORY, "Invalid config format (missing ':'): %s", token);
            errors++;
            token = strtok(NULL, ",");
            continue;
        }
        
        *colon = '\0';
        char* category_str = token;
        char* level_str = colon + 1;
        
        // Parse level
        debug_level_t level = DEBUG_LEVEL_NONE;
        if (strcasecmp(level_str, "none") == 0) level = DEBUG_LEVEL_NONE;
        else if (strcasecmp(level_str, "error") == 0) level = DEBUG_LEVEL_ERROR;
        else if (strcasecmp(level_str, "warn") == 0) level = DEBUG_LEVEL_WARN;
        else if (strcasecmp(level_str, "info") == 0) level = DEBUG_LEVEL_INFO;
        else if (strcasecmp(level_str, "debug") == 0) level = DEBUG_LEVEL_DEBUG;
        else if (strcasecmp(level_str, "trace") == 0) level = DEBUG_LEVEL_TRACE;
        else {
            DEBUG_WARN(DEBUG_CATEGORY_MEMORY, "Invalid debug level: %s", level_str);
            errors++;
            token = strtok(NULL, ",");
            continue;
        }
        
        // Parse category
        debug_category_t category = DEBUG_CATEGORY_NONE;
        if (strcasecmp(category_str, "uasync") == 0) category = DEBUG_CATEGORY_UASYNC;
        else if (strcasecmp(category_str, "ll_queue") == 0) category = DEBUG_CATEGORY_LL_QUEUE;

        else if (strcasecmp(category_str, "connection") == 0) category = DEBUG_CATEGORY_CONNECTION;
        else if (strcasecmp(category_str, "etcp") == 0) category = DEBUG_CATEGORY_ETCP;
        else if (strcasecmp(category_str, "crypto") == 0) category = DEBUG_CATEGORY_CRYPTO;
        else if (strcasecmp(category_str, "memory") == 0) category = DEBUG_CATEGORY_MEMORY;
        else if (strcasecmp(category_str, "timing") == 0) category = DEBUG_CATEGORY_TIMING;
        else if (strcasecmp(category_str, "all") == 0) category = DEBUG_CATEGORY_ALL;
        else if (strcasecmp(category_str, "config") == 0) category = DEBUG_CATEGORY_CONFIG;
        else if (strcasecmp(category_str, "tun") == 0) category = DEBUG_CATEGORY_TUN;
        else if (strcasecmp(category_str, "routing") == 0) category = DEBUG_CATEGORY_ROUTING;
        else {
            DEBUG_WARN(DEBUG_CATEGORY_MEMORY, "Unknown debug category: %s", category_str);
            errors++;
            token = strtok(NULL, ",");
            continue;
        }
        
        // Apply configuration
        if (category == DEBUG_CATEGORY_ALL) {
            debug_set_level(level);
        } else {
            debug_enable_category(category);
            // Note: per-category levels not yet implemented, use global level for now
        }
        
        token = strtok(NULL, ",");
    }
    
    free(config_copy);
    return (errors == 0) ? 0 : -1;
}