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package query
import (
"fmt"
"strings"
)
const MAX_CLAUSE_DEPTH int = 16
func (stmt Statement) Compile(b *strings.Builder) (*string, error) {
if stmt.Negated {
b.WriteString("NOT ")
}
switch stmt.Category {
case CAT_TITLE:
b.WriteString("title ")
case CAT_AUTHOR:
b.WriteString("author ")
case CAT_DATE:
b.WriteString("date ")
case CAT_FILETIME:
b.WriteString("fileTime ")
case CAT_TAGS:
b.WriteString("tags ")
case CAT_LINKS:
b.WriteString("links ")
default:
return nil, &CompileError{
fmt.Sprint("unknown or invalid category ", stmt.Category.String()),
}
}
switch stmt.Operator {
case OP_EQ:
if stmt.Category.IsSet() {
b.WriteString("IN ")
} else {
b.WriteString("= ")
}
case OP_AP:
b.WriteString("LIKE ")
case OP_NE:
b.WriteString("!= ")
case OP_LT:
b.WriteString("< ")
case OP_LE:
b.WriteString("<= ")
case OP_GE:
b.WriteString(">= ")
case OP_GT:
b.WriteString("> ")
default:
return nil, &CompileError{
fmt.Sprint("unknown or invalid operand ", stmt.Operator.String()),
}
}
switch stmt.Value.Type() {
case VAL_STR:
s, ok := stmt.Value.(StringValue)
if !ok {
panic(CompileError{"type corruption in string value"})
}
b.WriteString("(?) ")
return &s.S, nil
case VAL_DATETIME:
dt, ok := stmt.Value.(DatetimeValue)
if !ok {
panic(CompileError{"type corruption in datetime value"})
}
fmt.Fprint(b, dt.D.Unix(), " ")
default:
return nil, &CompileError{
fmt.Sprint("unknown or invalid value type ", stmt.Value.Type()),
}
}
return nil, nil
}
func (stmts Statements) Compile(b *strings.Builder, delim string) ([]string, error) {
var args []string
// TODO: handle meta category
for i, stmt := range stmts {
if i != 0 {
b.WriteString(delim)
}
b.WriteByte(' ')
arg, err := stmt.Compile(b)
if err != nil {
return nil, err
} else if arg != nil {
args = append(args, *arg)
}
}
return args, nil
}
func (root Clause) Compile() (string, []string, error) {
if d := root.Depth(); d > MAX_CLAUSE_DEPTH {
return "", nil, &CompileError{
fmt.Sprint("exceeded maximum clause depth of 8: ", d),
}
}
b := strings.Builder{}
args, err := root.buildCompile(&b)
if err != nil {
return "", nil, err
}
return b.String(), args, nil
}
func (c Clause) buildCompile(b *strings.Builder) ([]string, error) {
b.WriteString("( ")
var delim string
switch cop := c.Operator; cop {
case COP_AND:
delim = "AND"
case COP_OR:
delim = "OR"
default:
return nil, &CompileError{fmt.Sprint("invalid clause operator ", cop)}
}
args, err := c.Statements.Compile(b, delim)
if err != nil {
return nil, err
}
for _, clause := range c.Clauses {
b.WriteString(delim)
b.WriteByte(' ')
newArgs, err := clause.buildCompile(b)
if err != nil {
return nil, err
} else if newArgs != nil {
args = append(args, newArgs...)
}
}
b.WriteString(") ")
return args, nil
}
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