/*
 * w3m JavaScript Integration Implementation
 * 
 * Core JavaScript functionality for w3m using QuickJS engine.
 * This file implements the main JavaScript context management,
 * script execution, and buffer integration.
 */

#include "fm.h"

#ifdef USE_JAVASCRIPT

#include "w3m_javascript.h"
#include "w3m_dom.h"
#include "w3m_events.h"
#include <stdlib.h>
#include <string.h>

/* Global JavaScript configuration */
int w3m_js_enabled = 0;
int w3m_js_timeout = 5000;        /* 5 second timeout */
int w3m_js_memory_limit = 8388608; /* 8MB memory limit */
int w3m_js_network_enabled = 1;

/* JavaScript Context Management */

W3MJSContext *
w3m_js_create_context(void)
{
    W3MJSContext *ctx = GC_MALLOC(sizeof(W3MJSContext));
    if (!ctx) return NULL;
    
    ctx->runtime = JS_NewRuntime();
    if (!ctx->runtime) {
        GC_free(ctx);
        return NULL;
    }
    
    /* Set memory limit */
    JS_SetMemoryLimit(ctx->runtime, w3m_js_memory_limit);
    
    ctx->context = JS_NewContext(ctx->runtime);
    if (!ctx->context) {
        JS_FreeRuntime(ctx->runtime);
        GC_free(ctx);
        return NULL;
    }
    
    /* Get global object */
    ctx->global_obj = JS_GetGlobalObject(ctx->context);
    
    /* Initialize empty document and window objects */
    ctx->document_obj = JS_NULL;
    ctx->window_obj = JS_NULL;
    
    ctx->memory_limit = w3m_js_memory_limit;
    ctx->execution_timeout = w3m_js_timeout;
    
    return ctx;
}

void
w3m_js_destroy_context(W3MJSContext *ctx)
{
    if (!ctx) return;
    
    if (!JS_IsNull(ctx->global_obj))
        JS_FreeValue(ctx->context, ctx->global_obj);
    if (!JS_IsNull(ctx->document_obj))
        JS_FreeValue(ctx->context, ctx->document_obj);
    if (!JS_IsNull(ctx->window_obj))
        JS_FreeValue(ctx->context, ctx->window_obj);
    
    if (ctx->context)
        JS_FreeContext(ctx->context);
    if (ctx->runtime)
        JS_FreeRuntime(ctx->runtime);
    
    GC_free(ctx);
}

int
w3m_js_execute_script(W3MJSContext *ctx, const char *script, const char *filename)
{
    if (!ctx || !script) return 0;
    
    JSValue result = JS_Eval(ctx->context, script, strlen(script), 
                            filename ? filename : "<script>", 
                            JS_EVAL_TYPE_GLOBAL);
    
    if (JS_IsException(result)) {
        /* Handle JavaScript error */
        JSValue exception = JS_GetException(ctx->context);
        const char *error_msg = JS_ToCString(ctx->context, exception);
        w3m_js_report_error(ctx, error_msg ? error_msg : "Unknown JavaScript error");
        if (error_msg) JS_FreeCString(ctx->context, error_msg);
        JS_FreeValue(ctx->context, exception);
        JS_FreeValue(ctx->context, result);
        return 0;
    }
    
    JS_FreeValue(ctx->context, result);
    return 1;
}

void
w3m_js_set_timeout(W3MJSContext *ctx, int timeout_ms)
{
    if (ctx) {
        ctx->execution_timeout = timeout_ms;
    }
}

void
w3m_js_set_memory_limit(W3MJSContext *ctx, int limit_bytes)
{
    if (ctx && ctx->runtime) {
        ctx->memory_limit = limit_bytes;
        JS_SetMemoryLimit(ctx->runtime, limit_bytes);
    }
}

/* Buffer JavaScript Integration */

BufferJSState *
w3m_js_init_buffer_state(Buffer *buf)
{
    if (!buf) return NULL;
    
    BufferJSState *state = GC_MALLOC(sizeof(BufferJSState));
    if (!state) return NULL;
    
    state->js_ctx = w3m_js_create_context();
    if (!state->js_ctx) {
        GC_free(state);
        return NULL;
    }
    
    state->script_objects = NULL;
    state->script_count = 0;
    state->pending_scripts = NULL;
    state->pending_count = 0;
    state->scripts_enabled = w3m_js_enabled;
    
    /* Initialize DOM for this buffer */
    buf->js_document = w3m_dom_create_document(buf);
    if (buf->js_document) {
        w3m_js_bind_dom_objects(state->js_ctx, buf);
    }
    
    /* Initialize event system */
    buf->js_events = (struct W3MEventSystem *)w3m_events_create_system();
    if (buf->js_events) {
        w3m_events_bind_to_js(state->js_ctx, (W3MEventSystem *)buf->js_events);
    }
    
    return state;
}

void
w3m_js_cleanup_buffer_state(BufferJSState *state)
{
    if (!state) return;
    
    /* Free pending scripts */
    if (state->pending_scripts) {
        for (int i = 0; i < state->pending_count; i++) {
            if (state->pending_scripts[i]) {
                GC_free(state->pending_scripts[i]);
            }
        }
        GC_free(state->pending_scripts);
    }
    
    /* Free script objects */
    if (state->script_objects) {
        for (int i = 0; i < state->script_count; i++) {
            if (!JS_IsNull(state->script_objects[i])) {
                JS_FreeValue(state->js_ctx->context, state->script_objects[i]);
            }
        }
        GC_free(state->script_objects);
    }
    
    /* Destroy JavaScript context */
    w3m_js_destroy_context(state->js_ctx);
    
    GC_free(state);
}

void
w3m_js_add_pending_script(BufferJSState *state, const char *script)
{
    if (!state || !script) return;
    
    /* Expand array if needed */
    if (state->pending_count == 0) {
        state->pending_scripts = GC_MALLOC(sizeof(char*) * 10);
        if (!state->pending_scripts) return;
    } else if (state->pending_count % 10 == 0) {
        char **new_scripts = GC_MALLOC(sizeof(char*) * (state->pending_count + 10));
        if (!new_scripts) return;
        memcpy(new_scripts, state->pending_scripts, sizeof(char*) * state->pending_count);
        GC_free(state->pending_scripts);
        state->pending_scripts = new_scripts;
    }
    
    /* Copy script content */
    int len = strlen(script);
    state->pending_scripts[state->pending_count] = GC_MALLOC(len + 1);
    if (state->pending_scripts[state->pending_count]) {
        strcpy(state->pending_scripts[state->pending_count], script);
        state->pending_count++;
    }
}

void
w3m_js_execute_pending_scripts(BufferJSState *state)
{
    if (!state || !state->scripts_enabled) return;
    
    for (int i = 0; i < state->pending_count; i++) {
        if (state->pending_scripts[i]) {
            w3m_js_execute_script(state->js_ctx, state->pending_scripts[i], NULL);
        }
    }
}

/* DOM Integration */

void
w3m_js_bind_dom_objects(W3MJSContext *ctx, Buffer *buf)
{
    if (!ctx || !buf || !buf->js_document) return;
    
    /* This will be implemented in w3m_dom.c */
    w3m_dom_bind_to_js(ctx, buf->js_document);
}

/* Utility Functions */

char *
w3m_js_value_to_string(W3MJSContext *ctx, JSValue val)
{
    if (!ctx) return NULL;
    
    const char *str = JS_ToCString(ctx->context, val);
    if (!str) return NULL;
    
    int len = strlen(str);
    char *result = GC_MALLOC(len + 1);
    if (result) {
        strcpy(result, str);
    }
    
    JS_FreeCString(ctx->context, str);
    return result;
}

void
w3m_js_report_error(W3MJSContext *ctx, const char *msg)
{
    /* For now, just ignore errors silently */
    /* In future, could log to status line or debug output */
    (void)ctx;
    (void)msg;
}

#endif /* USE_JAVASCRIPT */