package main

import (
	`errors`
	`go/ast`
	`go/token`
	`log`
	`strings`

	`github.com/oriser/regroup`
)

/*
	getParamSpec takes an ast.Decl d and returns a slice of
	ParamConst found in it.

	If no ParamConst are found, foundParams will be nil.
*/
func getValueSpec(d ast.Decl) (foundParams []*ParamConst) {

	var ok bool
	var idx int
	var gd *ast.GenDecl
	var spec ast.Spec
	var vs *ast.ValueSpec
	var vsId *ast.Ident
	var nm *ast.Ident
	var bl *ast.BasicLit

	if gd, ok = d.(*ast.GenDecl); !ok || gd.Tok != token.CONST {
		return
	}

	for _, spec = range gd.Specs {
		if vs, ok = spec.(*ast.ValueSpec); !ok {
			continue
		}
		if vs.Type != nil {
			if vsId, ok = vs.Type.(*ast.Ident); !ok || vsId.Name != matchType {
				continue
			}
		}
		for idx, nm = range vs.Names {
			if !strings.HasPrefix(nm.Name, pfx) {
				continue
			}
			if bl, ok = vs.Values[idx].(*ast.BasicLit); !ok {
				continue
			}

			foundParams = append(
				foundParams,
				&ParamConst{
					ConstName: nm.Name,
					// UriParamName: bl.Value,
					UriParamName: stripQuotes(bl.Value),
				},
			)
		}
	}

	return
}

/*
	stripQuotes removes Golang-AST defining quotes.
	This probably doesn't work for multiline, but should be fine for our purposes.
*/
func stripQuotes(inStr string) (outStr string) {

	var err error
	var matches map[string]string
	var nomchErr *regroup.NoMatchFoundError = new(regroup.NoMatchFoundError)

	outStr = inStr

	if matches, err = stripQuotesPtrn.Groups(inStr); err != nil {
		if errors.As(err, &nomchErr) {
			err = nil
			return
		} else {
			log.Panicln(err)
		}
	}

	for _, v := range matches {
		if v != "" {
			outStr = v
			return
		}
	}

	return
}