// Copyright 2017 Unknwon

//

// Licensed under the Apache 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://www.apache.org/licenses/LICENSE-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 ini

import (

	"bytes"

	"errors"

	"fmt"

	"io"

	"io/ioutil"

	"os"

	"strings"

	"sync"

)

// File represents a combination of one or more INI files in memory.

type File struct {

	options     LoadOptions

	dataSources []dataSource

	// Should make things safe, but sometimes doesn't matter.

	BlockMode bool

	lock      sync.RWMutex

	// To keep data in order.

	sectionList []string

	// To keep track of the index of a section with same name.

	// This meta list is only used with non-unique section names are allowed.

	sectionIndexes []int

	// Actual data is stored here.

	sections map[string][]*Section

	NameMapper

	ValueMapper

}

// newFile initializes File object with given data sources.

func newFile(dataSources []dataSource, opts LoadOptions) *File {

	if len(opts.KeyValueDelimiters) == 0 {

		opts.KeyValueDelimiters = "=:"

	}

	if len(opts.KeyValueDelimiterOnWrite) == 0 {

		opts.KeyValueDelimiterOnWrite = "="

	}

	if len(opts.ChildSectionDelimiter) == 0 {

		opts.ChildSectionDelimiter = "."

	}

	return &File{

		BlockMode:   true,

		dataSources: dataSources,

		sections:    make(map[string][]*Section),

		options:     opts,

	}

}

// Empty returns an empty file object.

func Empty(opts ...LoadOptions) *File {

	var opt LoadOptions

	if len(opts) > 0 {

		opt = opts[0]

	}

	// Ignore error here, we are sure our data is good.

	f, _ := LoadSources(opt, []byte(""))

	return f

}

// NewSection creates a new section.

func (f *File) NewSection(name string) (*Section, error) {

	if len(name) == 0 {

		return nil, errors.New("empty section name")

	}

	if (f.options.Insensitive || f.options.InsensitiveSections) && name != DefaultSection {

		name = strings.ToLower(name)

	}

	if f.BlockMode {

		f.lock.Lock()

		defer f.lock.Unlock()

	}

	if !f.options.AllowNonUniqueSections && inSlice(name, f.sectionList) {

		return f.sections[name][0], nil

	}

	f.sectionList = append(f.sectionList, name)

	// NOTE: Append to indexes must happen before appending to sections,

	// otherwise index will have off-by-one problem.

	f.sectionIndexes = append(f.sectionIndexes, len(f.sections[name]))

	sec := newSection(f, name)

	f.sections[name] = append(f.sections[name], sec)

	return sec, nil

}

// NewRawSection creates a new section with an unparseable body.

func (f *File) NewRawSection(name, body string) (*Section, error) {

	section, err := f.NewSection(name)

	if err != nil {

		return nil, err

	}

	section.isRawSection = true

	section.rawBody = body

	return section, nil

}

// NewSections creates a list of sections.

func (f *File) NewSections(names ...string) (err error) {

	for _, name := range names {

		if _, err = f.NewSection(name); err != nil {

			return err

		}

	}

	return nil

}

// GetSection returns section by given name.

func (f *File) GetSection(name string) (*Section, error) {

	secs, err := f.SectionsByName(name)

	if err != nil {

		return nil, err

	}

	return secs[0], err

}

// SectionsByName returns all sections with given name.

func (f *File) SectionsByName(name string) ([]*Section, error) {

	if len(name) == 0 {

		name = DefaultSection

	}

	if f.options.Insensitive || f.options.InsensitiveSections {

		name = strings.ToLower(name)

	}

	if f.BlockMode {

		f.lock.RLock()

		defer f.lock.RUnlock()

	}

	secs := f.sections[name]

	if len(secs) == 0 {

		return nil, fmt.Errorf("section %q does not exist", name)

	}

	return secs, nil

}

// Section assumes named section exists and returns a zero-value when not.

func (f *File) Section(name string) *Section {

	sec, err := f.GetSection(name)

	if err != nil {

		sec, _ = f.NewSection(name)

		return sec

	}

	return sec

}

// SectionWithIndex assumes named section exists and returns a new section when not.

func (f *File) SectionWithIndex(name string, index int) *Section {

	secs, err := f.SectionsByName(name)

	if err != nil || len(secs) <= index {

		// NOTE: It's OK here because the only possible error is empty section name,

		// but if it's empty, this piece of code won't be executed.

		newSec, _ := f.NewSection(name)

		return newSec

	}

	return secs[index]

}

// Sections returns a list of Section stored in the current instance.

func (f *File) Sections() []*Section {

	if f.BlockMode {

		f.lock.RLock()

		defer f.lock.RUnlock()

	}

	sections := make([]*Section, len(f.sectionList))

	for i, name := range f.sectionList {

		sections[i] = f.sections[name][f.sectionIndexes[i]]

	}

	return sections

}

// ChildSections returns a list of child sections of given section name.

func (f *File) ChildSections(name string) []*Section {

	return f.Section(name).ChildSections()

}

// SectionStrings returns list of section names.

func (f *File) SectionStrings() []string {

	list := make([]string, len(f.sectionList))

	copy(list, f.sectionList)

	return list

}

// DeleteSection deletes a section or all sections with given name.

func (f *File) DeleteSection(name string) {

	secs, err := f.SectionsByName(name)

	if err != nil {

		return

	}

	for i := 0; i < len(secs); i++ {

		// For non-unique sections, it is always needed to remove the first one so

		// in the next iteration, the subsequent section continue having index 0.

		// Ignoring the error as index 0 never returns an error.

		_ = f.DeleteSectionWithIndex(name, 0)

	}

}

// DeleteSectionWithIndex deletes a section with given name and index.

func (f *File) DeleteSectionWithIndex(name string, index int) error {

	if !f.options.AllowNonUniqueSections && index != 0 {

		return fmt.Errorf("delete section with non-zero index is only allowed when non-unique sections is enabled")

	}

	if len(name) == 0 {

		name = DefaultSection

	}

	if f.options.Insensitive || f.options.InsensitiveSections {

		name = strings.ToLower(name)

	}

	if f.BlockMode {

		f.lock.Lock()

		defer f.lock.Unlock()

	}

	// Count occurrences of the sections

	occurrences := 0

	sectionListCopy := make([]string, len(f.sectionList))

	copy(sectionListCopy, f.sectionList)

	for i, s := range sectionListCopy {

		if s != name {

			continue

		}

		if occurrences == index {

			if len(f.sections[name]) <= 1 {

				delete(f.sections, name) // The last one in the map

			} else {

				f.sections[name] = append(f.sections[name][:index], f.sections[name][index+1:]...)

			}

			// Fix section lists

			f.sectionList = append(f.sectionList[:i], f.sectionList[i+1:]...)

			f.sectionIndexes = append(f.sectionIndexes[:i], f.sectionIndexes[i+1:]...)

		} else if occurrences > index {

			// Fix the indices of all following sections with this name.

			f.sectionIndexes[i-1]--

		}

		occurrences++

	}

	return nil

}

func (f *File) reload(s dataSource) error {

	r, err := s.ReadCloser()

	if err != nil {

		return err

	}

	defer r.Close()

	return f.parse(r)

}

// Reload reloads and parses all data sources.

func (f *File) Reload() (err error) {

	for _, s := range f.dataSources {

		if err = f.reload(s); err != nil {

			// In loose mode, we create an empty default section for nonexistent files.

			if os.IsNotExist(err) && f.options.Loose {

				_ = f.parse(bytes.NewBuffer(nil))

				continue

			}

			return err

		}

		if f.options.ShortCircuit {

			return nil

		}

	}

	return nil

}

// Append appends one or more data sources and reloads automatically.

func (f *File) Append(source interface{}, others ...interface{}) error {

	ds, err := parseDataSource(source)

	if err != nil {

		return err

	}

	f.dataSources = append(f.dataSources, ds)

	for _, s := range others {

		ds, err = parseDataSource(s)

		if err != nil {

			return err

		}

		f.dataSources = append(f.dataSources, ds)

	}

	return f.Reload()

}

func (f *File) writeToBuffer(indent string) (*bytes.Buffer, error) {

	equalSign := DefaultFormatLeft + f.options.KeyValueDelimiterOnWrite + DefaultFormatRight

	if PrettyFormat || PrettyEqual {

		equalSign = fmt.Sprintf(" %s ", f.options.KeyValueDelimiterOnWrite)

	}

	// Use buffer to make sure target is safe until finish encoding.

	buf := bytes.NewBuffer(nil)

	for i, sname := range f.sectionList {

		sec := f.SectionWithIndex(sname, f.sectionIndexes[i])

		if len(sec.Comment) > 0 {

			// Support multiline comments

			lines := strings.Split(sec.Comment, LineBreak)

			for i := range lines {

				if lines[i][0] != '#' && lines[i][0] != ';' {

					lines[i] = "; " + lines[i]

				} else {

					lines[i] = lines[i][:1] + " " + strings.TrimSpace(lines[i][1:])

				}

				if _, err := buf.WriteString(lines[i] + LineBreak); err != nil {

					return nil, err

				}

			}

		}

		if i > 0 || DefaultHeader || (i == 0 && strings.ToUpper(sec.name) != DefaultSection) {

			if _, err := buf.WriteString("[" + sname + "]" + LineBreak); err != nil {

				return nil, err

			}

		} else {

			// Write nothing if default section is empty

			if len(sec.keyList) == 0 {

				continue

			}

		}

		if sec.isRawSection {

			if _, err := buf.WriteString(sec.rawBody); err != nil {

				return nil, err

			}

				// Put a line between sections

				if _, err := buf.WriteString(LineBreak); err != nil {

					return nil, err

				}

			}

			continue

		}

		// Count and generate alignment length and buffer spaces using the

		// longest key. Keys may be modified if they contain certain characters so

		// we need to take that into account in our calculation.

		alignLength := 0

		if PrettyFormat {

			for _, kname := range sec.keyList {