// Copyright © 2013 Steve Francia <spf@spf13.com>.
//
// Licensed under the Simple Public License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://opensource.org/licenses/Simple-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package hugolib

import (
	"bytes"
	"html/template"
	"reflect"
	"strings"
	"unicode"

	jww "github.com/spf13/jwalterweatherman"
)

type ShortcodeFunc func([]string) string

type Shortcode struct {
	Name string
	Func ShortcodeFunc
}

type ShortcodeWithPage struct {
	Params interface{}
	Inner  template.HTML
	Page   *Page
}

func (scp *ShortcodeWithPage) Get(key interface{}) interface{} {
	if reflect.ValueOf(scp.Params).Len() == 0 {
		return nil
	}

	var x reflect.Value

	switch key.(type) {
	case int64, int32, int16, int8, int:
		if reflect.TypeOf(scp.Params).Kind() == reflect.Map {
			return "error: cannot access named params by position"
		} else if reflect.TypeOf(scp.Params).Kind() == reflect.Slice {
			x = reflect.ValueOf(scp.Params).Index(int(reflect.ValueOf(key).Int()))
		}
	case string:
		if reflect.TypeOf(scp.Params).Kind() == reflect.Map {
			x = reflect.ValueOf(scp.Params).MapIndex(reflect.ValueOf(key))
			if !x.IsValid() {
				return ""
			}
		} else if reflect.TypeOf(scp.Params).Kind() == reflect.Slice {
			if reflect.ValueOf(scp.Params).Len() == 1 && reflect.ValueOf(scp.Params).Index(0).String() == "" {
				return nil
			}
			return "error: cannot access positional params by string name"
		}
	}

	switch x.Kind() {
	case reflect.String:
		return x.String()
	case reflect.Int64, reflect.Int32, reflect.Int16, reflect.Int8, reflect.Int:
		return x.Int()
	default:
		return x
	}

}

type Shortcodes map[string]ShortcodeFunc

func ShortcodesHandle(stringToParse string, p *Page, t Template) string {
	leadStart := strings.Index(stringToParse, `{{%`)
	if leadStart >= 0 {
		leadEnd := strings.Index(stringToParse[leadStart:], `%}}`) + leadStart
		if leadEnd > leadStart {
			name, par := SplitParams(stringToParse[leadStart+3 : leadEnd])
			tmpl := GetTemplate(name, t)
			if tmpl == nil {
				return stringToParse
			}
			params := Tokenize(par)
			// Always look for closing tag.
			endStart, endEnd := FindEnd(stringToParse[leadEnd:], name)
			var data = &ShortcodeWithPage{Params: params, Page: p}
			if endStart > 0 {
				s := stringToParse[leadEnd+3 : leadEnd+endStart]
				data.Inner = template.HTML(CleanP(ShortcodesHandle(s, p, t)))
				remainder := CleanP(stringToParse[leadEnd+endEnd:])

				return CleanP(stringToParse[:leadStart]) +
					ShortcodeRender(tmpl, data) +
					CleanP(ShortcodesHandle(remainder, p, t))
			}
			return CleanP(stringToParse[:leadStart]) +
				ShortcodeRender(tmpl, data) +
				CleanP(ShortcodesHandle(stringToParse[leadEnd+3:], p,
					t))
		}
	}
	return stringToParse
}

// Clean up odd behavior when closing tag is on first line
// or opening tag is on the last line due to extra line in markdown file
func CleanP(str string) string {
	if strings.HasSuffix(strings.TrimSpace(str), "<p>") {
		idx := strings.LastIndex(str, "<p>")
		str = str[:idx]
	}

	if strings.HasPrefix(strings.TrimSpace(str), "</p>") {
		str = str[strings.Index(str, "</p>")+5:]
	}

	return str
}

func FindEnd(str string, name string) (int, int) {
	var endPos int
	var startPos int
	var try []string

	try = append(try, "{{% /"+name+" %}}")
	try = append(try, "{{% /"+name+"%}}")
	try = append(try, "{{%/"+name+"%}}")
	try = append(try, "{{%/"+name+" %}}")

	lowest := len(str)
	for _, x := range try {
		start := strings.Index(str, x)
		if start < lowest && start > 0 {
			startPos = start
			endPos = startPos + len(x)
		}
	}

	return startPos, endPos
}

func GetTemplate(name string, t Template) *template.Template {
	if x := t.Lookup("shortcodes/" + name + ".html"); x != nil {
		return x
	}
	return t.Lookup("_internal/shortcodes/" + name + ".html")
}

func StripShortcodes(stringToParse string) string {
	posStart := strings.Index(stringToParse, "{{%")
	if posStart > 0 {
		posEnd := strings.Index(stringToParse[posStart:], "%}}") + posStart
		if posEnd > posStart {
			newString := stringToParse[:posStart] + StripShortcodes(stringToParse[posEnd+3:])
			return newString
		}
	}
	return stringToParse
}

func CleanupSpacesAroundEquals(rawfirst []string) []string {
	var first = make([]string, 0)

	for i := 0; i < len(rawfirst); i++ {
		v := rawfirst[i]
		index := strings.Index(v, "=")

		if index == len(v)-1 {
			// Trailing '='
			if len(rawfirst) > i {
				if v == "=" {
					first[len(first)-1] = first[len(first)-1] + v + rawfirst[i+1] // concat prior with this and next
					i++                                                           // Skip next
				} else {
					// Trailing ' = '
					first = append(first, v+rawfirst[i+1]) // append this token and the next
					i++                                    // Skip next
				}
			} else {
				break
			}
		} else if index == 0 {
			// Leading '='
			first[len(first)-1] = first[len(first)-1] + v // concat this token to the prior one
			continue
		} else {
			first = append(first, v)
		}
	}

	return first
}

func Tokenize(in string) interface{} {
	var final = make([]string, 0)

	// if there isn't a space or an equal sign, no need to parse
	if strings.Index(in, " ") < 0 && strings.Index(in, "=") < 0 {
		return append(final, in)
	}

	var keys = make([]string, 0)
	inQuote := false
	start := 0

	first := CleanupSpacesAroundEquals(strings.Fields(in))

	for i, v := range first {
		index := strings.Index(v, "=")
		if !inQuote {
			if index > 1 {
				keys = append(keys, v[:index])
				v = v[index+1:]
			}
		}

		// Adjusted to handle htmlencoded and non htmlencoded input
		if !strings.HasPrefix(v, "&ldquo;") && !strings.HasPrefix(v, "\"") && !inQuote {
			final = append(final, v)
		} else if inQuote && (strings.HasSuffix(v, "&rdquo;") ||
			strings.HasSuffix(v, "\"")) && !strings.HasSuffix(v, "\\\"") {
			if strings.HasSuffix(v, "\"") {
				first[i] = v[:len(v)-1]
			} else {
				first[i] = v[:len(v)-7]
			}
			final = append(final, strings.Join(first[start:i+1], " "))
			inQuote = false
		} else if (strings.HasPrefix(v, "&ldquo;") ||
			strings.HasPrefix(v, "\"")) && !inQuote {
			if strings.HasSuffix(v, "&rdquo;") || strings.HasSuffix(v,
				"\"") {
				if strings.HasSuffix(v, "\"") {
					if len(v) > 1 {
						final = append(final, v[1:len(v)-1])
					} else {
						final = append(final, "")
					}
				} else {
					final = append(final, v[7:len(v)-7])
				}
			} else {
				start = i
				if strings.HasPrefix(v, "\"") {
					first[i] = v[1:]
				} else {
					first[i] = v[7:]
				}
				inQuote = true
			}
		}

		// No closing "... just make remainder the final token
		if inQuote && i == len(first) {
			final = append(final, first[start:]...)
		}
	}

	if len(keys) > 0 && (len(keys) != len(final)) {
		// This will happen if the quotes aren't balanced
		return final
	}

	if len(keys) > 0 {
		var m = make(map[string]string)
		for i, k := range keys {
			m[k] = final[i]
		}

		return m
	}

	return final
}

func SplitParams(in string) (name string, par2 string) {
	newIn := strings.TrimSpace(in)
	i := strings.IndexFunc(newIn, unicode.IsSpace)
	if i < 1 {
		return strings.TrimSpace(in), ""
	}

	return strings.TrimSpace(newIn[:i+1]), strings.TrimSpace(newIn[i+1:])
}

func ShortcodeRender(tmpl *template.Template, data *ShortcodeWithPage) string {
	buffer := new(bytes.Buffer)
	err := tmpl.Execute(buffer, data)
	if err != nil {
		jww.ERROR.Println("error processing shortcode", tmpl.Name(), "\n ERR:", err)
		jww.WARN.Println(data)
	}
	return buffer.String()
}
