/*
 * Copyright 2011 Jacek Caban for CodeWeavers
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <assert.h>

#include "vbscript.h"
#include "parse.h"
#include "parser.tab.h"

#include "wine/debug.h"

WINE_DEFAULT_DEBUG_CHANNEL(vbscript);

typedef struct {
    parser_ctx_t parser;

    unsigned instr_cnt;
    unsigned instr_size;
    vbscode_t *code;
} compile_ctx_t;

static HRESULT compile_expression(compile_ctx_t*,expression_t*);

static inline void *compiler_alloc(vbscode_t *vbscode, size_t size)
{
    return vbsheap_alloc(&vbscode->heap, size);
}

static WCHAR *compiler_alloc_string(vbscode_t *vbscode, const WCHAR *str)
{
    size_t size;
    WCHAR *ret;

    size = (strlenW(str)+1)*sizeof(WCHAR);
    ret = compiler_alloc(vbscode, size);
    if(ret)
        memcpy(ret, str, size);
    return ret;
}

static inline instr_t *instr_ptr(compile_ctx_t *ctx, unsigned id)
{
    assert(id < ctx->instr_cnt);
    return ctx->code->instrs + id;
}

static unsigned push_instr(compile_ctx_t *ctx, vbsop_t op)
{
    assert(ctx->instr_size && ctx->instr_size >= ctx->instr_cnt);

    if(ctx->instr_size == ctx->instr_cnt) {
        instr_t *new_instr;

        new_instr = heap_realloc(ctx->code->instrs, ctx->instr_size*2*sizeof(instr_t));
        if(!new_instr)
            return -1;

        ctx->code->instrs = new_instr;
        ctx->instr_size *= 2;
    }

    ctx->code->instrs[ctx->instr_cnt].op = op;
    return ctx->instr_cnt++;
}

static HRESULT push_instr_int(compile_ctx_t *ctx, vbsop_t op, LONG arg)
{
    unsigned ret;

    ret = push_instr(ctx, op);
    if(ret == -1)
        return E_OUTOFMEMORY;

    instr_ptr(ctx, ret)->arg1.lng = arg;
    return S_OK;
}

static HRESULT push_instr_str(compile_ctx_t *ctx, vbsop_t op, const WCHAR *arg)
{
    unsigned instr;
    WCHAR *str;

    str = compiler_alloc_string(ctx->code, arg);
    if(!str)
        return E_OUTOFMEMORY;

    instr = push_instr(ctx, op);
    if(instr == -1)
        return E_OUTOFMEMORY;

    instr_ptr(ctx, instr)->arg1.str = str;
    return S_OK;
}

static HRESULT push_instr_double(compile_ctx_t *ctx, vbsop_t op, double arg)
{
    unsigned instr;
    double *d;

    d = compiler_alloc(ctx->code, sizeof(double));
    if(!d)
        return E_OUTOFMEMORY;

    instr = push_instr(ctx, op);
    if(instr == -1)
        return E_OUTOFMEMORY;

    *d = arg;
    instr_ptr(ctx, instr)->arg1.dbl = d;
    return S_OK;
}

static BSTR alloc_bstr_arg(compile_ctx_t *ctx, const WCHAR *str)
{
    if(!ctx->code->bstr_pool_size) {
        ctx->code->bstr_pool = heap_alloc(8 * sizeof(BSTR));
        if(!ctx->code->bstr_pool)
            return NULL;
        ctx->code->bstr_pool_size = 8;
    }else if(ctx->code->bstr_pool_size == ctx->code->bstr_cnt) {
       BSTR *new_pool;

        new_pool = heap_realloc(ctx->code->bstr_pool, ctx->code->bstr_pool_size*2*sizeof(BSTR));
        if(!new_pool)
            return NULL;

        ctx->code->bstr_pool = new_pool;
        ctx->code->bstr_pool_size *= 2;
    }

    ctx->code->bstr_pool[ctx->code->bstr_cnt] = SysAllocString(str);
    if(!ctx->code->bstr_pool[ctx->code->bstr_cnt])
        return NULL;

    return ctx->code->bstr_pool[ctx->code->bstr_cnt++];
}

static HRESULT push_instr_bstr_uint(compile_ctx_t *ctx, vbsop_t op, const WCHAR *arg1, unsigned arg2)
{
    unsigned instr;
    BSTR bstr;

    bstr = alloc_bstr_arg(ctx, arg1);
    if(!bstr)
        return E_OUTOFMEMORY;

    instr = push_instr(ctx, op);
    if(instr == -1)
        return E_OUTOFMEMORY;

    instr_ptr(ctx, instr)->arg1.bstr = bstr;
    instr_ptr(ctx, instr)->arg2.uint = arg2;
    return S_OK;
}

static HRESULT compile_args(compile_ctx_t *ctx, expression_t *args, unsigned *ret)
{
    unsigned arg_cnt = 0;
    HRESULT hres;

    while(args) {
        hres = compile_expression(ctx, args);
        if(FAILED(hres))
            return hres;

        arg_cnt++;
        args = args->next;
    }

    *ret = arg_cnt;
    return S_OK;
}

static HRESULT compile_member_expression(compile_ctx_t *ctx, member_expression_t *expr, BOOL ret_val)
{
    unsigned arg_cnt = 0;
    HRESULT hres;

    hres = compile_args(ctx, expr->args, &arg_cnt);
    if(FAILED(hres))
        return hres;

    if(expr->obj_expr) {
        FIXME("obj_expr not implemented\n");
        hres = E_NOTIMPL;
    }else {
        hres = push_instr_bstr_uint(ctx, ret_val ? OP_icall : OP_icallv, expr->identifier, arg_cnt);
    }

    return hres;
}

static HRESULT compile_unary_expression(compile_ctx_t *ctx, unary_expression_t *expr, vbsop_t op)
{
    HRESULT hres;

    hres = compile_expression(ctx, expr->subexpr);
    if(FAILED(hres))
        return hres;

    return push_instr(ctx, op) == -1 ? E_OUTOFMEMORY : S_OK;
}

static HRESULT compile_binary_expression(compile_ctx_t *ctx, binary_expression_t *expr, vbsop_t op)
{
    HRESULT hres;

    hres = compile_expression(ctx, expr->left);
    if(FAILED(hres))
        return hres;

    hres = compile_expression(ctx, expr->right);
    if(FAILED(hres))
        return hres;

    return push_instr(ctx, op) == -1 ? E_OUTOFMEMORY : S_OK;
}

static HRESULT compile_expression(compile_ctx_t *ctx, expression_t *expr)
{
    switch(expr->type) {
    case EXPR_BOOL:
        return push_instr_int(ctx, OP_bool, ((bool_expression_t*)expr)->value);
    case EXPR_CONCAT:
        return compile_binary_expression(ctx, (binary_expression_t*)expr, OP_concat);
    case EXPR_DOUBLE:
        return push_instr_double(ctx, OP_double, ((double_expression_t*)expr)->value);
    case EXPR_EMPTY:
        return push_instr(ctx, OP_empty) != -1 ? S_OK : E_OUTOFMEMORY;
    case EXPR_EQUAL:
        return compile_binary_expression(ctx, (binary_expression_t*)expr, OP_equal);
    case EXPR_MEMBER:
        return compile_member_expression(ctx, (member_expression_t*)expr, TRUE);
    case EXPR_NOT:
        return compile_unary_expression(ctx, (unary_expression_t*)expr, OP_not);
    case EXPR_NULL:
        return push_instr(ctx, OP_null) != -1 ? S_OK : E_OUTOFMEMORY;
    case EXPR_STRING:
        return push_instr_str(ctx, OP_string, ((string_expression_t*)expr)->value);
    case EXPR_USHORT:
        return push_instr_int(ctx, OP_short, ((int_expression_t*)expr)->value);
    case EXPR_ULONG:
        return push_instr_int(ctx, OP_long, ((int_expression_t*)expr)->value);
    default:
        FIXME("Unimplemented expression type %d\n", expr->type);
        return E_NOTIMPL;
    }

    return S_OK;
}

static HRESULT compile_statement(compile_ctx_t *ctx, statement_t *stat)
{
    HRESULT hres;

    while(stat) {
        switch(stat->type) {
        case STAT_CALL:
            hres = compile_member_expression(ctx, ((call_statement_t*)stat)->expr, FALSE);
            break;
        default:
            FIXME("Unimplemented statement type %d\n", stat->type);
            hres = E_NOTIMPL;
        }

        if(FAILED(hres))
            return hres;
        stat = stat->next;
    }

    return S_OK;
}

static HRESULT compile_func(compile_ctx_t *ctx, statement_t *stat, function_t *func)
{
    HRESULT hres;

    func->code_off = ctx->instr_cnt;

    hres = compile_statement(ctx, stat);
    if(FAILED(hres))
        return hres;

    if(push_instr(ctx, OP_ret) == -1)
        return E_OUTOFMEMORY;

    return S_OK;
}

void release_vbscode(vbscode_t *code)
{
    unsigned i;

    list_remove(&code->entry);

    for(i=0; i < code->bstr_cnt; i++)
        SysFreeString(code->bstr_pool[i]);

    vbsheap_free(&code->heap);

    heap_free(code->bstr_pool);
    heap_free(code->source);
    heap_free(code->instrs);
    heap_free(code);
}

static vbscode_t *alloc_vbscode(compile_ctx_t *ctx, const WCHAR *source)
{
    vbscode_t *ret;

    ret = heap_alloc(sizeof(*ret));
    if(!ret)
        return NULL;

    ret->source = heap_strdupW(source);
    if(!ret->source) {
        heap_free(ret);
        return NULL;
    }

    ret->instrs = heap_alloc(32*sizeof(instr_t));
    if(!ret->instrs) {
        release_vbscode(ret);
        return NULL;
    }

    ctx->instr_cnt = 0;
    ctx->instr_size = 32;
    vbsheap_init(&ret->heap);

    ret->option_explicit = ctx->parser.option_explicit;

    ret->bstr_pool = NULL;
    ret->bstr_pool_size = 0;
    ret->bstr_cnt = 0;

    ret->global_code.code_ctx = ret;

    list_init(&ret->entry);
    return ret;
}

HRESULT compile_script(script_ctx_t *script, const WCHAR *src, vbscode_t **ret)
{
    compile_ctx_t ctx;
    HRESULT hres;

    hres = parse_script(&ctx.parser, src);
    if(FAILED(hres))
        return hres;

    ctx.code = alloc_vbscode(&ctx, src);
    if(!ctx.code)
        return E_OUTOFMEMORY;

    hres = compile_func(&ctx, ctx.parser.stats, &ctx.code->global_code);
    if(FAILED(hres)) {
        release_vbscode(ctx.code);
        return hres;
    }

    list_add_tail(&script->code_list, &ctx.code->entry);
    *ret = ctx.code;
    return S_OK;
}