#include <string.h>

#include <stdarg.h>

#include <assert.h>

#include <limits.h>

#include "sp_vm_api.h"

#include "sp_vm_basecontext.h"

#include "sp_vm_engine.h"

using namespace SourcePawn;

extern SourcePawnEngine g_SourcePawn;

#define CELLBOUNDMAX	(INT_MAX/sizeof(cell_t))

#define STACKMARGIN		((cell_t)(16*sizeof(cell_t)))

int GlobalDebugBreak(sp_context_t *ctx, uint32_t frm, uint32_t cip)

{

	g_SourcePawn.RunTracer(ctx, frm, cip);

	return SP_ERROR_NONE;

}

BaseContext::BaseContext(sp_context_t *_ctx)

{

	ctx = _ctx;

	ctx->context = this;

	ctx->dbreak = GlobalDebugBreak;

	m_InExec = false;

	m_CustomMsg = false;

	m_Runnable = true;

	m_funcsnum = ctx->vmbase->FunctionCount(ctx);

	m_priv_funcs = NULL;

	m_pub_funcs = NULL;

	/**

	 * Note: Since the m_plugin member will never change,

	 * it is safe to assume the function count will never change

	 */

	if (m_funcsnum && m_priv_funcs == NULL)

	{

		m_priv_funcs = new CFunction *[m_funcsnum];

		memset(m_priv_funcs, 0, sizeof(CFunction *) * m_funcsnum);

	} else {

		m_priv_funcs = NULL;

	}

	if (ctx->plugin->info.publics_num && m_pub_funcs == NULL)

	{

		m_pub_funcs = new CFunction *[ctx->plugin->info.publics_num];

		memset(m_pub_funcs, 0, sizeof(CFunction *) * ctx->plugin->info.publics_num);

	} else {

		m_pub_funcs = NULL;

	}

}

void BaseContext::FlushFunctionCache()

{

	if (m_pub_funcs)

	{

		for (uint32_t i=0; i<ctx->plugin->info.publics_num; i++)

		{

			delete m_pub_funcs[i];

			m_pub_funcs[i] = NULL;

		}

	}

	if (m_priv_funcs)

	{

		for (unsigned int i=0; i<m_funcsnum; i++)

		{

			delete m_priv_funcs[i];

			m_priv_funcs[i] = NULL;

		}

	}

}

BaseContext::~BaseContext()

{

	FlushFunctionCache();

	delete [] m_pub_funcs;

	m_pub_funcs = NULL;

	delete [] m_priv_funcs;

	m_priv_funcs = NULL;

}

void BaseContext::SetContext(sp_context_t *_ctx)

{

	if (!_ctx)

	{

		return;

	}

	ctx = _ctx;

	ctx->context = this;

	ctx->dbreak = GlobalDebugBreak;

	FlushFunctionCache();

}

IVirtualMachine *BaseContext::GetVirtualMachine()

{

	return (IVirtualMachine *)ctx->vmbase;

}

sp_context_t *BaseContext::GetContext()

{

	return ctx;

}

bool BaseContext::IsDebugging()

{

	return (ctx->flags & SPFLAG_PLUGIN_DEBUG);

}

int BaseContext::SetDebugBreak(SPVM_DEBUGBREAK newpfn, SPVM_DEBUGBREAK *oldpfn)

{

	if (!IsDebugging())

	{

		return SP_ERROR_NOTDEBUGGING;

	}

	*oldpfn = ctx->dbreak;

	ctx->dbreak = newpfn;

	return SP_ERROR_NONE;

}

IPluginDebugInfo *BaseContext::GetDebugInfo()

{

	return this;

}

int BaseContext::Execute(uint32_t code_addr, cell_t *result)

{

	if (!m_Runnable)

	{

		return SP_ERROR_NOT_RUNNABLE;

	}

	IVirtualMachine *vm = (IVirtualMachine *)ctx->vmbase;

	uint32_t pushcount = ctx->pushcount;

	int err;

	PushCell(pushcount++);

	ctx->pushcount = 0;

	cell_t save_sp = ctx->sp;

	cell_t save_hp = ctx->hp;

	bool wasExec = m_InExec;

	/* Clear the error state, if any */

	ctx->n_err = SP_ERROR_NONE;

	ctx->n_idx = 0;

	m_InExec = true;

	m_MsgCache[0] = '\0';

	m_CustomMsg = false;

	g_SourcePawn.PushTracer(ctx);

	err = vm->ContextExecute(ctx, code_addr, result);

	m_InExec = wasExec;

	/**

	 * :TODO: Calling from a plugin in here will erase the cached message...

	 * Should that be documented?

	 */

	g_SourcePawn.PopTracer(err, m_CustomMsg ? m_MsgCache : NULL);

#if defined _DEBUG

	if (err == SP_ERROR_NONE)

	{

		assert(ctx->sp - pushcount * sizeof(cell_t) == save_sp);

		assert(ctx->hp == save_hp);

	}

#endif

	if (err != SP_ERROR_NONE)

	{

		ctx->sp = save_sp;

		ctx->hp = save_hp;

	}

	return err;

}

void BaseContext::SetErrorMessage(const char *msg, va_list ap)

{

	m_CustomMsg = true;

	vsnprintf(m_MsgCache, sizeof(m_MsgCache), msg, ap);

}

void BaseContext::ThrowNativeErrorEx(int error, const char *msg, ...)

{

	if (!m_InExec)

	{

		return;

	}

	ctx->n_err = error;

	if (msg)

	{

		va_list ap;

		va_start(ap, msg);

		SetErrorMessage(msg, ap);

		va_end(ap);

	}

}

cell_t BaseContext::ThrowNativeError(const char *msg, ...)

{

	if (!m_InExec)

	{

		return 0;

	}

	ctx->n_err = SP_ERROR_NATIVE;

	if (msg)

	{

		va_list ap;

		va_start(ap, msg);

		SetErrorMessage(msg, ap);

		va_end(ap);

	}

	return 0;

}

int BaseContext::HeapAlloc(unsigned int cells, cell_t *local_addr, cell_t **phys_addr)

{

	cell_t *addr;

	ucell_t realmem;

#if 0

	if (cells > CELLBOUNDMAX)

	{

		return SP_ERROR_ARAM;

	}

#else

	assert(cells < CELLBOUNDMAX);

#endif

	realmem = cells * sizeof(cell_t);

	/**

	 * Check if the space between the heap and stack is sufficient.

	 */

	if ((cell_t)(ctx->sp - ctx->hp - realmem) < STACKMARGIN)

	{

		return SP_ERROR_HEAPLOW;

	}

	addr = (cell_t *)(ctx->memory + ctx->hp);

	/* store size of allocation in cells */

	*addr = (cell_t)cells;

	addr++;

	ctx->hp += sizeof(cell_t);

	*local_addr = ctx->hp;

	if (phys_addr)

	{

		*phys_addr = addr;

	}

	ctx->hp += realmem;

	return SP_ERROR_NONE;

}

int BaseContext::HeapPop(cell_t local_addr)

{

	cell_t cellcount;

	cell_t *addr;

	/* check the bounds of this address */

	local_addr -= sizeof(cell_t);

	if (local_addr < ctx->heap_base || local_addr >= ctx->sp)

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	addr = (cell_t *)(ctx->memory + local_addr);

	cellcount = (*addr) * sizeof(cell_t);

	/* check if this memory count looks valid */

	if ((signed)(ctx->hp - cellcount - sizeof(cell_t)) != local_addr)

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	ctx->hp = local_addr;

	return SP_ERROR_NONE;

}

int BaseContext::HeapRelease(cell_t local_addr)

{

	if (local_addr < ctx->heap_base)

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	ctx->hp = local_addr - sizeof(cell_t);

	return SP_ERROR_NONE;

}

int BaseContext::FindNativeByName(const char *name, uint32_t *index)

{

	int high;

	high = ctx->plugin->info.natives_num - 1;

	for (uint32_t i=0; i<ctx->plugin->info.natives_num; i++)

	{

		if (strcmp(ctx->natives[i].name, name) == 0)

		{

			if (index)

			{

				*index = i;

			}

			return SP_ERROR_NONE;

		}

	}

	return SP_ERROR_NOT_FOUND;

}

int BaseContext::GetNativeByIndex(uint32_t index, sp_native_t **native)

{

	if (index >= ctx->plugin->info.natives_num)

	{

		return SP_ERROR_INDEX;

	}

	if (native)

	{

		*native = &(ctx->natives[index]);

	}

	return SP_ERROR_NONE;

}

uint32_t BaseContext::GetNativesNum()

{

	return ctx->plugin->info.natives_num;

}

int BaseContext::FindPublicByName(const char *name, uint32_t *index)

{

	int diff, high, low;

	uint32_t mid;

	high = ctx->plugin->info.publics_num - 1;

	low = 0;

	while (low <= high)

	{

		mid = (low + high) / 2;

		diff = strcmp(ctx->publics[mid].name, name);

		if (diff == 0)

		{

			if (index)

			{

				*index = mid;

			}

			return SP_ERROR_NONE;

		} else if (diff < 0) {

			low = mid + 1;

		} else {

			high = mid - 1;

		}

	}

	return SP_ERROR_NOT_FOUND;

}

int BaseContext::GetPublicByIndex(uint32_t index, sp_public_t **pblic)

{

	if (index >= ctx->plugin->info.publics_num)

	{

		return SP_ERROR_INDEX;

	}

	if (pblic)

	{

		*pblic = &(ctx->publics[index]);

	}

	return SP_ERROR_NONE;

}

uint32_t BaseContext::GetPublicsNum()

{

	return ctx->plugin->info.publics_num;

}

int BaseContext::GetPubvarByIndex(uint32_t index, sp_pubvar_t **pubvar)

{

	if (index >= ctx->plugin->info.pubvars_num)

	{

		return SP_ERROR_INDEX;

	}

	if (pubvar)

	{

		*pubvar = &(ctx->pubvars[index]);

	}

	return SP_ERROR_NONE;

}

int BaseContext::FindPubvarByName(const char *name, uint32_t *index)

{

	int diff, high, low;

	uint32_t mid;

	high = ctx->plugin->info.pubvars_num - 1;

	low = 0;

	while (low <= high)

	{

		mid = (low + high) / 2;

		diff = strcmp(ctx->pubvars[mid].name, name);

		if (diff == 0)

		{

			if (index)

			{

				*index = mid;

			}

			return SP_ERROR_NONE;

		} else if (diff < 0) {

			low = mid + 1;

		} else {

			high = mid - 1;

		}

	}

	return SP_ERROR_NOT_FOUND;

}

int BaseContext::GetPubvarAddrs(uint32_t index, cell_t *local_addr, cell_t **phys_addr)

{

	if (index >= ctx->plugin->info.pubvars_num)

	{

		return SP_ERROR_INDEX;

	}

	*local_addr = ctx->plugin->info.pubvars[index].address;

	*phys_addr = ctx->pubvars[index].offs;

	return SP_ERROR_NONE;

}

uint32_t BaseContext::GetPubVarsNum()

{

	return ctx->plugin->info.pubvars_num;

}

int BaseContext::BindNatives(const sp_nativeinfo_t *natives, unsigned int num, int overwrite)

{

	uint32_t i, j, max;

	max = ctx->plugin->info.natives_num;

	for (i=0; i<max; i++)

	{

		if ((ctx->natives[i].status == SP_NATIVE_BOUND) && !overwrite)

		{

			continue;

		}

		for (j=0; (natives[j].name) && (!num || j<num); j++)

		{

			if (!strcmp(ctx->natives[i].name, natives[j].name))

			{

				ctx->natives[i].pfn = natives[j].func;

				ctx->natives[i].status = SP_NATIVE_BOUND;

			}

		}

	}

	return SP_ERROR_NONE;

}

int BaseContext::BindNative(const sp_nativeinfo_t *native)

{

	uint32_t index;

	int err;

	if ((err = FindNativeByName(native->name, &index)) != SP_ERROR_NONE)

	{

		return err;

	}

	ctx->natives[index].pfn = native->func;

	ctx->natives[index].status = SP_NATIVE_BOUND;

	return SP_ERROR_NONE;

}

int BaseContext::BindNativeToAny(SPVM_NATIVE_FUNC native)

{

	uint32_t nativesnum, i;

	nativesnum = ctx->plugin->info.natives_num;

	for (i=0; i<nativesnum; i++)

	{

		if (ctx->natives[i].status == SP_NATIVE_UNBOUND)

		{

			ctx->natives[i].pfn = native;

			ctx->natives[i].status = SP_NATIVE_BOUND;

		}

	}

	return SP_ERROR_NONE;

}

int BaseContext::LocalToPhysAddr(cell_t local_addr, cell_t **phys_addr)

{

	if (((local_addr >= ctx->hp) && (local_addr < ctx->sp)) || (local_addr < 0) || ((ucell_t)local_addr >= ctx->mem_size))

	{

		return SP_ERROR_INVALID_ADDRESS;

	}

	if (phys_addr)

	{

		*phys_addr = (cell_t *)(ctx->memory + local_addr);

	}

	return SP_ERROR_NONE;

}

int BaseContext::PushCell(cell_t value)

{

	if ((ctx->hp + STACKMARGIN) > (cell_t)(ctx->sp - sizeof(cell_t)))

	{

		return SP_ERROR_STACKLOW;

	}

	ctx->sp -= sizeof(cell_t);

	*(cell_t *)(ctx->memory + ctx->sp) = value;

	ctx->pushcount++;

	return SP_ERROR_NONE;

}

int BaseContext::PushCellsFromArray(cell_t array[], unsigned int numcells)

{

	unsigned int i;

	int err;

	for (i=0; i<numcells; i++)

	{

		if ((err = PushCell(array[i])) != SP_ERROR_NONE)

		{

			ctx->sp += (cell_t)(i * sizeof(cell_t));

			ctx->pushcount -= i;

			return err;

		}

	}

	return SP_ERROR_NONE;

}

int BaseContext::PushCellArray(cell_t *local_addr, cell_t **phys_addr, cell_t array[], unsigned int numcells)

{

	cell_t *ph_addr;

	int err;

	if ((err = HeapAlloc(numcells, local_addr, &ph_addr)) != SP_ERROR_NONE)

	{

		return err;

	}

	memcpy(ph_addr, array, numcells * sizeof(cell_t));

	if ((err = PushCell(*local_addr)) != SP_ERROR_NONE)

	{

		HeapRelease(*local_addr);

		return err;

	}