package main
import (
"fmt"
"strings"
)
type (
filter struct {
idx int
where []string
params []interface{}
Vals map[string]string
}
)
func newFilter() *filter {
return &filter{
idx: 0,
where: []string{},
params: []interface{}{},
Vals: map[string]string{},
}
}
func (f *filter) filterChecks(c *Context) {
args := c.r.URL.Query()
for name, val := range args {
if !strings.HasPrefix(name, "filter-") {
continue
}
arg := strings.TrimPrefix(name, "filter-")
switch arg {
case "command":
if val[0] == "" {
continue
}
f.Add("co.id", "=", val[0], "int")
f.Vals[arg] = val[0]
case "search":
if val[0] == "" {
continue
}
f.Add(`n.name`, `like`, strings.ReplaceAll(val[0], "*", "%"), "text")
f.Vals[arg] = val[0]
case "state":
if val[0] == "" {
continue
}
f.Add("states[1]", ">=", val[0], "int")
f.Vals[arg] = val[0]
case "ack":
if val[0] == "" {
continue
}
if val[0] != "true" && val[0] != "false" {
continue
}
f.Add("acknowledged", "=", val[0], "boolean")
f.Vals[arg] = val[0]
case "mapping":
if val[0] == "" {
continue
}
f.Add("ac.mapping_id", "=", val[0], "int")
f.Vals[arg] = val[0]
}
}
}
// Add a new where clause element which will be joined at the end.
func (f *filter) Add(field, op string, arg interface{}, castTo string) {
f.idx += 1
f.where = append(f.where, fmt.Sprintf("%s %s $%d::%s", field, op, f.idx, castTo))
f.params = append(f.params, arg)
}
// AddSpecial lets you add a special where clause comparison where you can
// wrap the argument in whatevery you like.
//
// Your string has to contain %d. This will place the index of the variable
// in the query string.
//
// Example:
// AddSpecial("foo", "=", "to_tsvector('english', $%d), search)
func (f *filter) AddSpecial(field, op, special string, arg interface{}) {
f.idx += 1
f.where = append(f.where, fmt.Sprintf("%s %s "+special, field, op, f.idx))
f.params = append(f.params, arg)
}
// Join takes all where clauses and joins them together with the AND operator.
// The result and all collected parameters are then returned.
func (f *filter) Join() (string, []interface{}) {
return strings.Join(f.where, " and "), f.params
}
