// SiYuan - Refactor your thinking
// Copyright (c) 2020-present, b3log.org
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <https://www.gnu.org/licenses/>.

package filesys

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/88250/lute"
	"github.com/88250/lute/parse"
	"github.com/88250/lute/render"
	jsoniter "github.com/json-iterator/go"
	"github.com/siyuan-note/filelock"
	"github.com/siyuan-note/logging"
	"github.com/siyuan-note/siyuan/kernel/cache"
	"github.com/siyuan-note/siyuan/kernel/treenode"
	"github.com/siyuan-note/siyuan/kernel/util"
)

func LoadTrees(ids []string) (ret map[string]*parse.Tree) {
	ret, tmpCache := map[string]*parse.Tree{}, map[string]*parse.Tree{}
	bts := treenode.GetBlockTrees(ids)
	luteEngine := util.NewLute()
	for id, bt := range bts {
		tree := tmpCache[bt.RootID]
		if nil == tree {
			tree, _ = LoadTree(bt.BoxID, bt.Path, luteEngine)
			if nil == tree {
				logging.LogWarnf("load tree [%s] failed: %s", id, bt.Path)
				continue
			}
			tmpCache[bt.RootID] = tree
		}
		ret[id] = tree
	}
	return
}

func LoadTree(boxID, p string, luteEngine *lute.Lute) (ret *parse.Tree, err error) {
	filePath := filepath.Join(util.DataDir, boxID, p)
	data, err := filelock.ReadFile(filePath)
	if nil != err {
		logging.LogErrorf("load tree [%s] failed: %s", p, err)
		return
	}

	ret, err = LoadTreeByData(data, boxID, p, luteEngine)
	return
}

func LoadTreeByData(data []byte, boxID, p string, luteEngine *lute.Lute) (ret *parse.Tree, err error) {
	ret = parseJSON2Tree(boxID, p, data, luteEngine)
	if nil == ret {
		logging.LogErrorf("parse tree [%s] failed", p)
		err = errors.New("parse tree failed")
		return
	}
	ret.Path = p
	ret.Root.Path = p

	parts := strings.Split(p, "/")
	parts = parts[1 : len(parts)-1] // 去掉开头的斜杆和结尾的自己
	if 1 > len(parts) {
		ret.HPath = "/" + ret.Root.IALAttr("title")
		ret.Hash = treenode.NodeHash(ret.Root, ret, luteEngine)
		return
	}

	// 构造 HPath
	hPathBuilder := bytes.Buffer{}
	hPathBuilder.WriteString("/")
	for i, _ := range parts {
		var parentAbsPath string
		if 0 < i {
			parentAbsPath = strings.Join(parts[:i+1], "/")
		} else {
			parentAbsPath = parts[0]
		}
		parentAbsPath += ".sy"
		parentPath := parentAbsPath
		parentAbsPath = filepath.Join(util.DataDir, boxID, parentAbsPath)
		parentData, readErr := filelock.ReadFile(parentAbsPath)
		if nil != readErr {
			if os.IsNotExist(readErr) {
				// 子文档缺失父文档时自动补全 https://github.com/siyuan-note/siyuan/issues/7376
				parentTree := treenode.NewTree(boxID, parentPath, hPathBuilder.String()+"Untitled", "Untitled")
				if writeErr := WriteTree(parentTree); nil != writeErr {
					logging.LogErrorf("rebuild parent tree [%s] failed: %s", parentAbsPath, writeErr)
				} else {
					logging.LogInfof("rebuilt parent tree [%s]", parentAbsPath)
					treenode.UpsertBlockTree(parentTree)
				}
			} else {
				logging.LogWarnf("read parent tree data [%s] failed: %s", parentAbsPath, readErr)
			}
			hPathBuilder.WriteString("Untitled/")
			continue
		}

		ial := ReadDocIAL(parentData)
		if 1 > len(ial) {
			logging.LogWarnf("tree [%s] is corrupted", filepath.Join(boxID, p))
		}
		title := ial["title"]
		if "" == title {
			title = "Untitled"
		}
		hPathBuilder.WriteString(title)
		hPathBuilder.WriteString("/")
	}
	hPathBuilder.WriteString(ret.Root.IALAttr("title"))
	ret.HPath = hPathBuilder.String()
	ret.Hash = treenode.NodeHash(ret.Root, ret, luteEngine)
	return
}

func WriteTree(tree *parse.Tree) (err error) {
	data, filePath, err := prepareWriteTree(tree)
	if nil != err {
		return
	}

	if err = filelock.WriteFile(filePath, data); nil != err {
		msg := fmt.Sprintf("write data [%s] failed: %s", filePath, err)
		logging.LogErrorf(msg)
		return errors.New(msg)
	}

	afterWriteTree(tree)
	return
}

func prepareWriteTree(tree *parse.Tree) (data []byte, filePath string, err error) {
	luteEngine := util.NewLute() // 不关注用户的自定义解析渲染选项

	if nil == tree.Root.FirstChild {
		newP := treenode.NewParagraph()
		tree.Root.AppendChild(newP)
		tree.Root.SetIALAttr("updated", util.TimeFromID(newP.ID))
		treenode.UpsertBlockTree(tree)
	}

	filePath = filepath.Join(util.DataDir, tree.Box, tree.Path)
	if oldSpec := tree.Root.Spec; "" == oldSpec {
		parse.NestedInlines2FlattedSpans(tree, false)
		tree.Root.Spec = "1"
		logging.LogInfof("migrated tree [%s] from spec [%s] to [%s]", filePath, oldSpec, tree.Root.Spec)
	}
	tree.Root.SetIALAttr("type", "doc")
	renderer := render.NewJSONRenderer(tree, luteEngine.RenderOptions)
	data = renderer.Render()

	if !util.UseSingleLineSave {
		buf := bytes.Buffer{}
		buf.Grow(1024 * 1024 * 2)
		if err = json.Indent(&buf, data, "", "\t"); nil != err {
			return
		}
		data = buf.Bytes()
	}

	if err = os.MkdirAll(filepath.Dir(filePath), 0755); nil != err {
		return
	}
	return
}

func afterWriteTree(tree *parse.Tree) {
	docIAL := parse.IAL2MapUnEsc(tree.Root.KramdownIAL)
	cache.PutDocIAL(tree.Path, docIAL)
}

func parseJSON2Tree(boxID, p string, jsonData []byte, luteEngine *lute.Lute) (ret *parse.Tree) {
	var err error
	var needFix bool
	ret, needFix, err = ParseJSON(jsonData, luteEngine.ParseOptions)
	if nil != err {
		logging.LogErrorf("parse json [%s] to tree failed: %s", boxID+p, err)
		return
	}

	ret.Box = boxID
	ret.Path = p

	filePath := filepath.Join(util.DataDir, ret.Box, ret.Path)
	if oldSpec := ret.Root.Spec; "" == oldSpec {
		parse.NestedInlines2FlattedSpans(ret, false)
		ret.Root.Spec = "1"
		needFix = true
		logging.LogInfof("migrated tree [%s] from spec [%s] to [%s]", filePath, oldSpec, ret.Root.Spec)
	}
	if needFix {
		renderer := render.NewJSONRenderer(ret, luteEngine.RenderOptions)
		data := renderer.Render()

		if !util.UseSingleLineSave {
			buf := bytes.Buffer{}
			buf.Grow(1024 * 1024 * 2)
			if err = json.Indent(&buf, data, "", "\t"); nil != err {
				return
			}
			data = buf.Bytes()
		}

		if err = os.MkdirAll(filepath.Dir(filePath), 0755); nil != err {
			return
		}
		if err = filelock.WriteFile(filePath, data); nil != err {
			msg := fmt.Sprintf("write data [%s] failed: %s", filePath, err)
			logging.LogErrorf(msg)
		}
	}
	return
}

func ReadDocIAL(data []byte) (ret map[string]string) {
	ret = map[string]string{}
	val := jsoniter.Get(data, "Properties")
	if nil == val || val.ValueType() == jsoniter.InvalidValue {
		return
	}
	val.ToVal(&ret)
	return
}