/*
 * This file is part of LibCSS.
 * Licensed under the MIT License,
 *                http://www.opensource.org/licenses/mit-license.php
 * Copyright 2009 John-Mark Bell <jmb@netsurf-browser.org>
 */

#include <assert.h>
#include <string.h>

#include "bytecode/bytecode.h"
#include "bytecode/opcodes.h"
#include "parse/properties/properties.h"
#include "parse/properties/utils.h"

static css_error parse_margin_side(css_language *c,
		const parserutils_vector *vector, int *ctx,
		uint16_t op, css_style **result);

/**
 * Parse margin shorthand
 *
 * \param c       Parsing context
 * \param vector  Vector of tokens to process
 * \param ctx     Pointer to vector iteration context
 * \param result  Pointer to location to receive resulting style
 * \return CSS_OK on success,
 *         CSS_NOMEM on memory exhaustion,
 *         CSS_INVALID if the input is not valid
 *
 * Post condition: \a *ctx is updated with the next token to process
 *                 If the input is invalid, then \a *ctx remains unchanged.
 */
css_error parse_margin(css_language *c,
		const parserutils_vector *vector, int *ctx,
		css_style **result)
{
	int orig_ctx = *ctx;
	int prev_ctx;
	const css_token *token;
	css_style *top = NULL;
	css_style *right = NULL;
	css_style *bottom = NULL;
	css_style *left = NULL;
	css_style *ret = NULL;
	uint32_t num_sides = 0;
	uint32_t required_size;
	bool match;
	css_error error;

	/* Firstly, handle inherit */
	token = parserutils_vector_peek(vector, *ctx);
	if (token != NULL && token->type == CSS_TOKEN_IDENT &&
			(lwc_string_caseless_isequal(
			token->idata, c->strings[INHERIT],
			&match) == lwc_error_ok && match)) {
		uint32_t *bytecode;

		error = css_stylesheet_style_create(c->sheet,
			4 * sizeof(uint32_t), &ret);
		if (error != CSS_OK) {
			*ctx = orig_ctx;
			return error;
		}

		bytecode = (uint32_t *) ret->bytecode;

		*(bytecode++) = buildOPV(CSS_PROP_MARGIN_TOP,
				FLAG_INHERIT, 0);
		*(bytecode++) = buildOPV(CSS_PROP_MARGIN_RIGHT,
				FLAG_INHERIT, 0);
		*(bytecode++) = buildOPV(CSS_PROP_MARGIN_BOTTOM,
				FLAG_INHERIT, 0);
		*(bytecode++) = buildOPV(CSS_PROP_MARGIN_LEFT,
				FLAG_INHERIT, 0);

		parserutils_vector_iterate(vector, ctx);

		*result = ret;

		return CSS_OK;
	} else if (token == NULL) {
		/* No tokens -- clearly garbage */
		*ctx = orig_ctx;
		return CSS_INVALID;
	}

	/* Attempt to parse up to 4 widths */
	do {
		prev_ctx = *ctx;
		error = CSS_OK;

		/* Ensure that we're not about to parse another inherit */
		token = parserutils_vector_peek(vector, *ctx);
		if (token != NULL && token->type == CSS_TOKEN_IDENT &&
				(lwc_string_caseless_isequal(
				token->idata, c->strings[INHERIT],
				&match) == lwc_error_ok && match)) {
			error = CSS_INVALID;
			goto cleanup;
		}

		if (top == NULL &&
				(error = parse_margin_side(c, vector, ctx, 
				CSS_PROP_MARGIN_TOP, &top)) == CSS_OK) {
			num_sides = 1;
		} else if (right == NULL &&
				(error = parse_margin_side(c, vector, ctx, 
				CSS_PROP_MARGIN_RIGHT, &right)) == CSS_OK) {
			num_sides = 2;
		} else if (bottom == NULL &&
				(error = parse_margin_side(c, vector, ctx, 
				CSS_PROP_MARGIN_BOTTOM, &bottom)) == CSS_OK) {
			num_sides = 3;
		} else if (left == NULL &&
				(error = parse_margin_side(c, vector, ctx, 
				CSS_PROP_MARGIN_LEFT, &left)) == CSS_OK) {
			num_sides = 4;
		}

		if (error == CSS_OK) {
			consumeWhitespace(vector, ctx);

			token = parserutils_vector_peek(vector, *ctx);
		} else {
			/* Forcibly cause loop to exit */
			token = NULL;
		}
	} while (*ctx != prev_ctx && token != NULL);

	if (num_sides == 0) {
		error = CSS_INVALID;
		goto cleanup;
	}

	/* Calculate size of resultant style */
	if (num_sides == 1) {
		required_size = 4 * top->length;
	} else if (num_sides == 2) {
		required_size = 2 * top->length + 2 * right->length;
	} else if (num_sides == 3) {
		required_size = top->length + 2 * right->length + 
				bottom->length;
	} else {
		required_size = top->length + right->length +
				bottom->length + left->length;
	}

	error = css_stylesheet_style_create(c->sheet, required_size, &ret);
	if (error != CSS_OK)
		goto cleanup;

	required_size = 0;

	if (num_sides == 1) {
		uint32_t *opv = ((uint32_t *) top->bytecode);
		uint8_t flags = getFlags(*opv);
		uint16_t value = getValue(*opv);

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		*opv = buildOPV(CSS_PROP_MARGIN_RIGHT, flags, value);
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		*opv = buildOPV(CSS_PROP_MARGIN_BOTTOM, flags, value);
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		*opv = buildOPV(CSS_PROP_MARGIN_LEFT, flags, value);
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;
	} else if (num_sides == 2) {
		uint32_t *vopv = ((uint32_t *) top->bytecode);
		uint32_t *hopv = ((uint32_t *) right->bytecode);
		uint8_t vflags = getFlags(*vopv);
		uint8_t hflags = getFlags(*hopv);
		uint16_t vvalue = getValue(*vopv);
		uint16_t hvalue = getValue(*hopv);

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				right->bytecode, right->length);
		required_size += right->length;

		*vopv = buildOPV(CSS_PROP_MARGIN_BOTTOM, vflags, vvalue);
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		*hopv = buildOPV(CSS_PROP_MARGIN_LEFT, hflags, hvalue);
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				right->bytecode, right->length);
		required_size += right->length;
	} else if (num_sides == 3) {
		uint32_t *opv = ((uint32_t *) right->bytecode);
		uint8_t flags = getFlags(*opv);
		uint16_t value = getValue(*opv);

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				right->bytecode, right->length);
		required_size += right->length;

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				bottom->bytecode, bottom->length);
		required_size += bottom->length;

		*opv = buildOPV(CSS_PROP_MARGIN_LEFT, flags, value);
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				right->bytecode, right->length);
		required_size += right->length;
	} else {
		memcpy(((uint8_t *) ret->bytecode) + required_size,
				top->bytecode, top->length);
		required_size += top->length;

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				right->bytecode, right->length);
		required_size += right->length;

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				bottom->bytecode, bottom->length);
		required_size += bottom->length;

		memcpy(((uint8_t *) ret->bytecode) + required_size,
				left->bytecode, left->length);
		required_size += left->length;
	}

	assert(required_size == ret->length);

	/* Write the result */
	*result = ret;
	/* Invalidate ret, so that cleanup doesn't destroy it */
	ret = NULL;

	/* Clean up after ourselves */
cleanup:
	if (top)
		css_stylesheet_style_destroy(c->sheet, top);
	if (right)
		css_stylesheet_style_destroy(c->sheet, right);
	if (bottom)
		css_stylesheet_style_destroy(c->sheet, bottom);
	if (left)
		css_stylesheet_style_destroy(c->sheet, left);
	if (ret)
		css_stylesheet_style_destroy(c->sheet, ret);

	if (error != CSS_OK)
		*ctx = orig_ctx;

	return error;
}

/**
 * Parse margin-bottom
 *
 * \param c       Parsing context
 * \param vector  Vector of tokens to process
 * \param ctx     Pointer to vector iteration context
 * \param result  Pointer to location to receive resulting style
 * \return CSS_OK on success,
 *         CSS_NOMEM on memory exhaustion,
 *         CSS_INVALID if the input is not valid
 *
 * Post condition: \a *ctx is updated with the next token to process
 *                 If the input is invalid, then \a *ctx remains unchanged.
 */
css_error parse_margin_bottom(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_style **result)
{
	return parse_margin_side(c, vector, ctx, 
			CSS_PROP_MARGIN_BOTTOM, result);
}

/**
 * Parse margin-left
 *
 * \param c       Parsing context
 * \param vector  Vector of tokens to process
 * \param ctx     Pointer to vector iteration context
 * \param result  Pointer to location to receive resulting style
 * \return CSS_OK on success,
 *         CSS_NOMEM on memory exhaustion,
 *         CSS_INVALID if the input is not valid
 *
 * Post condition: \a *ctx is updated with the next token to process
 *                 If the input is invalid, then \a *ctx remains unchanged.
 */
css_error parse_margin_left(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_style **result)
{
	return parse_margin_side(c, vector, ctx, CSS_PROP_MARGIN_LEFT, result);
}

/**
 * Parse margin-right
 *
 * \param c       Parsing context
 * \param vector  Vector of tokens to process
 * \param ctx     Pointer to vector iteration context
 * \param result  Pointer to location to receive resulting style
 * \return CSS_OK on success,
 *         CSS_NOMEM on memory exhaustion,
 *         CSS_INVALID if the input is not valid
 *
 * Post condition: \a *ctx is updated with the next token to process
 *                 If the input is invalid, then \a *ctx remains unchanged.
 */
css_error parse_margin_right(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_style **result)
{
	return parse_margin_side(c, vector, ctx, CSS_PROP_MARGIN_RIGHT, result);
}

/**
 * Parse margin-top
 *
 * \param c       Parsing context
 * \param vector  Vector of tokens to process
 * \param ctx     Pointer to vector iteration context
 * \param result  Pointer to location to receive resulting style
 * \return CSS_OK on success,
 *         CSS_NOMEM on memory exhaustion,
 *         CSS_INVALID if the input is not valid
 *
 * Post condition: \a *ctx is updated with the next token to process
 *                 If the input is invalid, then \a *ctx remains unchanged.
 */
css_error parse_margin_top(css_language *c, 
		const parserutils_vector *vector, int *ctx, 
		css_style **result)
{
	return parse_margin_side(c, vector, ctx, CSS_PROP_MARGIN_TOP, result);
}

/**
 * Parse margin-{top,right,bottom,left}
 *
 * \param c       Parsing context
 * \param vector  Vector of tokens to process
 * \param ctx     Pointer to vector iteration context
 * \param result  Pointer to location to receive resulting style
 * \return CSS_OK on success,
 *         CSS_NOMEM on memory exhaustion,
 *         CSS_INVALID if the input is not valid
 *
 * Post condition: \a *ctx is updated with the next token to process
 *                 If the input is invalid, then \a *ctx remains unchanged.
 */
css_error parse_margin_side(css_language *c,
		const parserutils_vector *vector, int *ctx,
		uint16_t op, css_style **result)
{
	int orig_ctx = *ctx;
	css_error error;
	const css_token *token;
	uint8_t flags = 0;
	uint16_t value = 0;
	uint32_t opv;
	css_fixed length = 0;
	uint32_t unit = 0;
	uint32_t required_size;
	bool match;

	/* length | percentage | IDENT(auto, inherit) */
	token = parserutils_vector_peek(vector, *ctx);
	if (token == NULL) {
		*ctx = orig_ctx;
		return CSS_INVALID;
	}

	if (token->type == CSS_TOKEN_IDENT &&
			(lwc_string_caseless_isequal(
			token->idata, c->strings[INHERIT],
			&match) == lwc_error_ok && match)) {
		parserutils_vector_iterate(vector, ctx);
		flags = FLAG_INHERIT;
	} else if (token->type == CSS_TOKEN_IDENT &&
			(lwc_string_caseless_isequal(
			token->idata, c->strings[AUTO],
			&match) == lwc_error_ok && match)) {
		parserutils_vector_iterate(vector, ctx);
		value = MARGIN_AUTO;
	} else {
		error = parse_unit_specifier(c, vector, ctx, UNIT_PX,
				&length, &unit);
		if (error != CSS_OK) {
			*ctx = orig_ctx;
			return error;
		}

		if (unit & UNIT_ANGLE || unit & UNIT_TIME || unit & UNIT_FREQ) {
			*ctx = orig_ctx;
			return CSS_INVALID;
		}

		value = MARGIN_SET;
	}

	opv = buildOPV(op, flags, value);

	required_size = sizeof(opv);
	if ((flags & FLAG_INHERIT) == false && value == MARGIN_SET)
		required_size += sizeof(length) + sizeof(unit);

	/* Allocate result */
	error = css_stylesheet_style_create(c->sheet, required_size, result);
	if (error != CSS_OK) {
		*ctx = orig_ctx;
		return error;
	}

	/* Copy the bytecode to it */
	memcpy((*result)->bytecode, &opv, sizeof(opv));
	if ((flags & FLAG_INHERIT) == false && value == MARGIN_SET) {
		memcpy(((uint8_t *) (*result)->bytecode) + sizeof(opv),
				&length, sizeof(length));
		memcpy(((uint8_t *) (*result)->bytecode) + sizeof(opv) +
				sizeof(length), &unit, sizeof(unit));
	}

	return CSS_OK;
}