/*
 * Copyright (c) 2013 Kurt Jung (Gmail: kurt.w.jung)
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

package gofpdf

import (
	"bytes"
	"compress/zlib"
	"fmt"
	"math"
	"os"
	"regexp"
	"strings"
)

func round(f float64) int {
	if f < 0 {
		return -int(math.Floor(-f + 0.5))
	} else {
		return int(math.Floor(f + 0.5))
	}
}

func sprintf(fmtStr string, args ...interface{}) string {
	return fmt.Sprintf(fmtStr, args...)
}

// Returns true if the specified normal file exists
func fileExist(filename string) (ok bool) {
	info, err := os.Stat(filename)
	if err == nil {
		if ^os.ModePerm&info.Mode() == 0 {
			ok = true
		}
	}
	return ok
}

// Returns the size of the specified file; ok will be false
// if the file does not exist or is not an ordinary file
func fileSize(filename string) (size int64, ok bool) {
	info, err := os.Stat(filename)
	ok = err == nil
	if ok {
		size = info.Size()
	}
	return
}

// Returns a new buffer populated with the contents of the specified file
func bufferFromFile(fileStr string) (b *bytes.Buffer, err error) {
	var fl *os.File
	fl, err = os.Open(fileStr)
	if err != nil {
		return
	}
	defer fl.Close()
	b = new(bytes.Buffer)
	_, err = b.ReadFrom(fl)
	return
}

// Returns a zlib-compressed copy of the specified byte array
func sliceCompress(data []byte) []byte {
	var buf bytes.Buffer
	cmp := zlib.NewWriter(&buf)
	cmp.Write(data)
	cmp.Close()
	return buf.Bytes()
}

// Returns an uncompressed copy of the specified zlib-compressed byte array
func sliceUncompress(data []byte) (outData []byte, err error) {
	inBuf := bytes.NewBuffer(data)
	r, err := zlib.NewReader(inBuf)
	defer r.Close()
	if err == nil {
		var outBuf bytes.Buffer
		_, err = outBuf.ReadFrom(r)
		if err == nil {
			outData = outBuf.Bytes()
		}
	}
	return
}

// Convert 'ABCDEFG' to, for example, 'A,BCD,EFG'
func strDelimit(str string, sepstr string, sepcount int) string {
	pos := len(str) - sepcount
	for pos > 0 {
		str = str[:pos] + sepstr + str[pos:]
		pos = pos - sepcount
	}
	return str
}

type htmlSegmentType struct {
	cat  byte              // 'O' open tag, 'C' close tag, 'T' text
	str  string            // Literal text unchanged, tags are lower case
	attr map[string]string // Attribute keys are lower case
}

// Returns a list of HTML tags and literal elements. This is done with regular
// expressions, so the result is only marginally better than useless.
// Adapted from http://www.fpdf.org/
func htmlTokenize(htmlStr string) (list []htmlSegmentType) {
	list = make([]htmlSegmentType, 0, 16)
	htmlStr = strings.Replace(htmlStr, "\n", " ", -1)
	htmlStr = strings.Replace(htmlStr, "\r", "", -1)
	tagRe, _ := regexp.Compile(`(?U)<.*>`)
	attrRe, _ := regexp.Compile(`([^=]+)=["']?([^"']+)`)
	capList := tagRe.FindAllStringIndex(htmlStr, -1)
	if capList != nil {
		var seg htmlSegmentType
		var parts []string
		pos := 0
		for _, cap := range capList {
			if pos < cap[0] {
				seg.cat = 'T'
				seg.str = htmlStr[pos:cap[0]]
				seg.attr = nil
				list = append(list, seg)
			}
			if htmlStr[cap[0]+1] == '/' {
				seg.cat = 'C'
				seg.str = strings.ToLower(htmlStr[cap[0]+2 : cap[1]-1])
				seg.attr = nil
				list = append(list, seg)
			} else {
				// Extract attributes
				parts = strings.Split(htmlStr[cap[0]+1:cap[1]-1], " ")
				if len(parts) > 0 {
					for j, part := range parts {
						if j == 0 {
							seg.cat = 'O'
							seg.str = strings.ToLower(parts[0])
							seg.attr = make(map[string]string)
						} else {
							attrList := attrRe.FindAllStringSubmatch(part, -1)
							if attrList != nil {
								for _, attr := range attrList {
									seg.attr[strings.ToLower(attr[1])] = attr[2]
								}
							}
						}
					}
					list = append(list, seg)
				}
			}
			pos = cap[1]
		}
		if len(htmlStr) > pos {
			seg.cat = 'T'
			seg.str = htmlStr[pos:]
			seg.attr = nil
			list = append(list, seg)
		}
	}
	return
}

// Convert UTF-8 to UTF-16BE with BOM; from http://www.fpdf.org/
func utf8toutf16(s string) string {
	res := make([]byte, 0, 8)
	res = append(res, 0xFE, 0xFF)
	nb := len(s)
	i := 0
	for i < nb {
		c1 := byte(s[i])
		i++
		if c1 >= 224 {
			// 3-byte character
			c2 := byte(s[i])
			i++
			c3 := byte(s[i])
			i++
			res = append(res, ((c1&0x0F)<<4)+((c2&0x3C)>>2),
				((c2&0x03)<<6)+(c3&0x3F))
		} else if c1 >= 192 {
			// 2-byte character
			c2 := byte(s[i])
			i++
			res = append(res, ((c1 & 0x1C) >> 2),
				((c1&0x03)<<6)+(c2&0x3F))
		} else {
			// Single-byte character
			res = append(res, 0, c1)
		}
	}
	return string(res)
}

// Return a if cnd is true, otherwise b
func IntIf(cnd bool, a, b int) int {
	if cnd {
		return a
	} else {
		return b
	}
}

// Return aStr if cnd is true, otherwise bStr
func StrIf(cnd bool, aStr, bStr string) string {
	if cnd {
		return aStr
	} else {
		return bStr
	}
}