1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128


use std::collections::BTreeMap;
use std::collections::HashMap;

pub use versatile_data::{
    Data as Collection
    ,IdxSized
    ,Update
};
pub use idx_binary::IdxBinary;

mod collection;
pub use collection::{
    CollectionRow
};

mod relation;
pub use relation::{
    RelationIndex
};

mod transaction;
use transaction::Transaction;
pub use transaction::{
    TransactionRecord
};

pub struct Database{
    root_dir:String
    ,collections_map:HashMap<String,u32>
    ,collections:BTreeMap<u32,Collection>
    ,relation:RelationIndex
}
impl Database{
    pub fn new(dir:&str)->Result<Database,std::io::Error>{
        let root_dir=if dir.ends_with("/") || dir.ends_with("\\"){
            let mut d=dir.to_string();
            d.pop();
            d
        }else{
            dir.to_string()
        };
        let relation_key_names=IdxBinary::new(&(root_dir.to_string()+"/relation_key_name"))?;
        let relation_key=IdxSized::new(&(root_dir.to_string()+"/relation_key.i"))?;
        let relation_parent=IdxSized::new(&(root_dir.to_string()+"/relation_parent.i"))?;
        let relation_child=IdxSized::new(&(root_dir.to_string()+"/relation_child.i"))?;
        Ok(Database{
            root_dir
            ,collections:BTreeMap::new()
            ,collections_map:HashMap::new()
            ,relation:RelationIndex::new(
                relation_key_names
                ,relation_key
                ,relation_parent
                ,relation_child
            )
        })
    }

    fn collection_by_name_or_create(&mut self,name:&str)->Result<u32,std::io::Error>{
        let mut max_id=0;
        let collections_dir=self.root_dir.to_string()+"/collection/";
        if let Ok(dir)=std::fs::read_dir(&collections_dir){
            for d in dir.into_iter(){
                if let Ok(d)=d{
                    if let Ok(dt)=d.file_type(){
                        if dt.is_dir(){
                            if let Some(fname)=d.path().file_name(){
                                if let Some(fname)=fname.to_str(){
                                    let s: Vec<&str>=fname.split("_").collect();
                                    if s.len()>1{
                                        if let Ok(i)=s[0].parse(){
                                            max_id=std::cmp::max(max_id,i);
                                        }
                                        if s[1]==name{
                                            if let Some(path)=d.path().to_str(){
                                                let data=Collection::new(path)?;
                                                self.collections_map.insert(name.to_string(),max_id);
                                                self.collections.insert(
                                                    max_id
                                                    ,data
                                                );
                                                return Ok(max_id);
                                            }
                                        }
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
        let collection_id=max_id+1;
        let data=Collection::new(&(collections_dir+"/"+&collection_id.to_string()+"_"+name))?;
        self.collections_map.insert(name.to_string(),collection_id);
        self.collections.insert(
            collection_id
            ,data
        );
        Ok(collection_id)
    }
    pub fn collection(&self,id:u32)->Option<&Collection>{
        self.collections.get(&id)
    }
    pub fn collection_mut(&mut self,id:u32)->Option<&mut Collection>{
        self.collections.get_mut(&id)
    }
    pub fn collection_id(&mut self,name:&str)->Result<u32,std::io::Error>{
        if self.collections_map.contains_key(name){
            Ok(*self.collections_map.get(name).unwrap())
        }else{
            self.collection_by_name_or_create(name)
        }
    }
    pub fn begin_transaction(&mut self)->Transaction{
        Transaction::new(self)
    }
    pub fn relation_mut(&mut self)->&mut RelationIndex{
        &mut self.relation
    }
    pub fn relation(&self)->&RelationIndex{
        &self.relation
    }
    pub fn childs(&self,key:&str,parent:&CollectionRow){
        self.relation.childs(key,parent);
    }
}