#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <ctype.h>

#define MAX_COMMAND_LEN 4096
#define MAX_DIRECTIVES 16
#define MAX_VALUE_LEN 1024

typedef enum {
    UI_NONE,
    UI_STREAMLIT,
    UI_GRADIO,
    UI_HTML
} UiShell;

typedef enum {
    MEDIA_NONE,
    MEDIA_TEXT_TO_IMAGE,
    MEDIA_IMAGE_TO_IMAGE,
    MEDIA_IMAGE_TO_VIDEO,
    MEDIA_TEXT_TO_VIDEO
} MediaType;

typedef struct {
    char main_prompt[MAX_COMMAND_LEN];
    UiShell ui_shell;
    bool web_search_enabled;
    char model_id[MAX_VALUE_LEN];
    struct {
        MediaType type;
        char prompt[MAX_COMMAND_LEN];
    } media_ops[MAX_DIRECTIVES];
    int media_count;
    char url_redesign[MAX_VALUE_LEN];
    char source_image[MAX_VALUE_LEN];
    char reference_doc[MAX_VALUE_LEN];
    char others[MAX_DIRECTIVES][MAX_VALUE_LEN];
    int other_count;
} CommandSpec;

typedef struct {
    char message[MAX_VALUE_LEN];
    char type[32]; // "missing-url", "missing-image", "unknown-directive", "empty-value"
} Validation;

// Helper: trim whitespace from start and end of string
void trim(char *str) {
    char *end;
    while (isspace(*str)) str++;
    if (*str == '\0') return;
    end = str + strlen(str) - 1;
    while (end > str && isspace(*end)) end--;
    *(end + 1) = '\0';
}

// Helper: check if string starts with prefix (case-insensitive)
bool starts_with(const char *str, const char *prefix) {
    size_t len = strlen(prefix);
    if (strlen(str) < len) return false;
    for (size_t i = 0; i < len; i++) {
        if (tolower(str[i]) != tolower(prefix[i])) return false;
    }
    return true;
}

// Helper: extract value after colon (trim whitespace)
char* extract_value(const char *directive) {
    char *colon = strchr(directive, ':');
    if (!colon) return NULL;
    char *value = colon + 1;
    while (*value && isspace(*value)) value++;
    return value;
}

// Split command by top-level commas (ignore commas inside URLs)
int split_command(const char *input, char *parts[], int max_parts) {
    int count = 0;
    char *buf = strdup(input);
    char *ptr = buf;
    bool in_url = false;
    char quote = '\0';

    for (int i = 0; ptr[i] != '\0'; i++) {
        if (ptr[i] == '"' || ptr[i] == '\'') {
            if (quote == '\0') quote = ptr[i];
            else if (quote == ptr[i]) quote = '\0';
        }
        if (quote == '\0' && ptr[i] == ':' && i > 0 && ptr[i-1] == 'h') {
            // Look ahead for http(s)://
            if (i >= 4 && strncmp(&ptr[i-4], "http", 4) == 0) in_url = true;
        }
        if (quote == '\0' && !in_url && ptr[i] == ',' && i > 0 && ptr[i-1] != '\\') {
            ptr[i] = '\0';
            if (count < max_parts) {
                parts[count] = ptr;
                trim(parts[count]);
                count++;
            }
            ptr = &ptr[i+1];
            i = -1; // reset to re-check from start of new segment
        }
        if (in_url && ptr[i] == ' ') in_url = false; // URL ends at space
    }
    if (count < max_parts && strlen(ptr) > 0) {
        parts[count] = ptr;
        trim(parts[count]);
        count++;
    }
    free(buf);
    return count;
}

// Parse a single directive
bool parse_directive(const char *directive, CommandSpec *spec) {
    char lower_dir[1024];
    strcpy(lower_dir, directive);
    for (int i = 0; lower_dir[i]; i++) lower_dir[i] = tolower(lower_dir[i]);

    if (starts_with(lower_dir, "use streamlit")) {
        spec->ui_shell = UI_STREAMLIT;
        return true;
    }
    if (starts_with(lower_dir, "use gradio")) {
        spec->ui_shell = UI_GRADIO;
        return true;
    }
    if (starts_with(lower_dir, "use html")) {
        spec->ui_shell = UI_HTML;
        return true;
    }
    if (starts_with(lower_dir, "enable web search")) {
        spec->web_search_enabled = true;
        return true;
    }
    if (starts_with(lower_dir, "disable web search")) {
        spec->web_search_enabled = false;
        return true;
    }
    if (starts_with(lower_dir, "model:")) {
        char *val = extract_value(directive);
        if (val && strlen(val) > 0) {
            strncpy(spec->model_id, val, MAX_VALUE_LEN - 1);
            spec->model_id[MAX_VALUE_LEN - 1] = '\0';
            return true;
        } else {
            return false; // empty value
        }
    }
    if (starts_with(lower_dir, "redesign ")) {
        char *url = extract_value(directive);
        if (url && strlen(url) > 0) {
            strncpy(spec->url_redesign, url, MAX_VALUE_LEN - 1);
            spec->url_redesign[MAX_VALUE_LEN - 1] = '\0';
            return true;
        } else {
            return false; // missing URL
        }
    }
    if (starts_with(lower_dir, "generate images:")) {
        if (spec->media_count < MAX_DIRECTIVES) {
            char *prompt = extract_value(directive);
            if (prompt && strlen(prompt) > 0) {
                spec->media_ops[spec->media_count].type = MEDIA_TEXT_TO_IMAGE;
                strncpy(spec->media_ops[spec->media_count].prompt, prompt, MAX_COMMAND_LEN - 1);
                spec->media_ops[spec->media_count].prompt[MAX_COMMAND_LEN - 1] = '\0';
                spec->media_count++;
                return true;
            }
        }
        return false;
    }
    if (starts_with(lower_dir, "image to image:")) {
        if (spec->media_count < MAX_DIRECTIVES) {
            char *prompt = extract_value(directive);
            if (prompt && strlen(prompt) > 0) {
                spec->media_ops[spec->media_count].type = MEDIA_IMAGE_TO_IMAGE;
                strncpy(spec->media_ops[spec->media_count].prompt, prompt, MAX_COMMAND_LEN - 1);
                spec->media_ops[spec->media_count].prompt[MAX_COMMAND_LEN - 1] = '\0';
                spec->media_count++;
                return true;
            }
        }
        return false;
    }
    if (starts_with(lower_dir, "image to video:")) {
        if (spec->media_count < MAX_DIRECTIVES) {
            char *prompt = extract_value(directive);
            if (prompt && strlen(prompt) > 0) {
                spec->media_ops[spec->media_count].type = MEDIA_IMAGE_TO_VIDEO;
                strncpy(spec->media_ops[spec->media_count].prompt, prompt, MAX_COMMAND_LEN - 1);
                spec->media_ops[spec->media_count].prompt[MAX_COMMAND_LEN - 1] = '\0';
                spec->media_count++;
                return true;
            }
        }
        return false;
    }
    if (starts_with(lower_dir, "text to video:")) {
        if (spec->media_count < MAX_DIRECTIVES) {
            char *prompt = extract_value(directive);
            if (prompt && strlen(prompt) > 0) {
                spec->media_ops[spec->media_count].type = MEDIA_TEXT_TO_VIDEO;
                strncpy(spec->media_ops[spec->media_count].prompt, prompt, MAX_COMMAND_LEN - 1);
                spec->media_ops[spec->media_count].prompt[MAX_COMMAND_LEN - 1] = '\0';
                spec->media_count++;
                return true;
            }
        }
        return false;
    }

    // Unknown directive - treat as part of main prompt (non-fatal)
    return false;
}

// Parse entire command string into CommandSpec
CommandSpec parse_command(const char *input) {
    CommandSpec spec = {0};
    strcpy(spec.main_prompt, input);

    char *parts[MAX_DIRECTIVES + 1];
    int n = split_command(input, parts, MAX_DIRECTIVES + 1);

    if (n == 0) return spec;

    // First part is main prompt (unless it's a redesign)
    bool found_redesign = false;
    for (int i = 0; i < n; i++) {
        if (starts_with(parts[i], "redesign ")) {
            parse_directive(parts[i], &spec);
            found_redesign = true;
        }
    }

    if (!found_redesign) {
        // Extract main prompt as everything before first directive
        char *first = parts[0];
        if (strlen(first) > 0) {
            strncpy(spec.main_prompt, first, MAX_COMMAND_LEN - 1);
            spec.main_prompt[MAX_COMMAND_LEN - 1] = '\0';
        }
    }

    // Parse modifiers
    for (int i = 0; i < n; i++) {
        if (starts_with(parts[i], "redesign ")) continue; // Already handled
        if (!parse_directive(parts[i], &spec)) {
            // Unknown directive — do nothing (per spec: non-fatal, kept in main prompt)
        }
    }

    // Default model if not set
    if (strlen(spec.model_id) == 0) {
        strcpy(spec.model_id, "default-model");
    }

    return spec;
}

// Validate command against attachments (simplified mock)
Validation validate_command(CommandSpec *spec, bool has_source_image) {
    Validation v = {0};
    if (strlen(spec->url_redesign) > 0 && !strstr(spec->url_redesign, "http")) {
        strcpy(v.message, "URL required for redesign");
        strcpy(v.type, "missing-url");
        return v;
    }
    for (int i = 0; i < spec->media_count; i++) {
        if ((spec->media_ops[i].type == MEDIA_IMAGE_TO_IMAGE || spec->media_ops[i].type == MEDIA_IMAGE_TO_VIDEO) && !has_source_image) {
            strcpy(v.message, "No source image attached");
            strcpy(v.type, "missing-image");
            return v;
        }
    }
    // No errors
    v.type[0] = '\0';
    return v;
}

// Apply command to system state (mock implementation)
void apply_command(CommandSpec *spec) {
    printf("[APPLYING COMMAND]\n");
    printf("Main Prompt: %s\n", spec->main_prompt);
    printf("UI Shell: ");
    switch (spec->ui_shell) {
        case UI_STREAMLIT: printf("Streamlit\n"); break;
        case UI_GRADIO: printf("Gradio\n"); break;
        case UI_HTML: printf("HTML\n"); break;
        default: printf("None\n"); break;
    }
    printf("Web Search: %s\n", spec->web_search_enabled ? "Enabled" : "Disabled");
    printf("Model: %s\n", spec->model_id);
    if (strlen(spec->url_redesign) > 0) {
        printf("Redesign URL: %s\n", spec->url_redesign);
    }
    for (int i = 0; i < spec->media_count; i++) {
        char *type_str = "unknown";
        switch (spec->media_ops[i].type) {
            case MEDIA_TEXT_TO_IMAGE: type_str = "Text→Image"; break;
            case MEDIA_IMAGE_TO_IMAGE: type_str = "Image→Image"; break;
            case MEDIA_IMAGE_TO_VIDEO: type_str = "Image→Video"; break;
            case MEDIA_TEXT_TO_VIDEO: type_str = "Text→Video"; break;
        }
        printf("Media: %s → \"%s\"\n", type_str, spec->media_ops[i].prompt);
    }
}

// Main CLI entry point
int main() {
    char command[MAX_COMMAND_LEN];
    printf("Command Palette DSL (Type 'quit' to exit)\n");

    while (true) {
        printf("> ");
        if (!fgets(command, sizeof(command), stdin)) break;
        command[strcspn(command, "\n")] = 0; // remove newline

        if (strcmp(command, "quit") == 0) break;

        CommandSpec spec = parse_command(command);
        Validation validation = validate_command(&spec, false); // Mock: no image attached

        if (validation.type[0] != '\0') {
            printf("❌ Validation Error: [%s] %s\n", validation.type, validation.message);
        }

        apply_command(&spec);
        printf("\n");
    }

    return 0;
}