package tools

import (
	"context"
	"os"
	"path/filepath"
	"strings"
	"testing"
)

// editIn runs the edit tool against a temp file. It returns the resulting file
// content and the tool error.
func editIn(t *testing.T, content, input string) (string, error) {
	t.Helper()
	dir := t.TempDir()
	p := filepath.Join(dir, "f.txt")
	if err := os.WriteFile(p, []byte(content), 0o644); err != nil {
		t.Fatal(err)
	}
	reg := NewRegistry()
	for _, tl := range BuiltinIn(dir, NewFence(), nil) {
		if err := reg.Register(tl); err != nil {
			t.Fatal(err)
		}
	}
	e, _ := reg.Get("edit")
	input = strings.ReplaceAll(input, "PATH", strings.ReplaceAll(p, `\`, `\\`))
	if _, err := e.Run(context.Background(), input); err != nil {
		return "", err
	}
	got, err := os.ReadFile(p)
	if err != nil {
		t.Fatal(err)
	}
	return string(got), nil
}

// TestEditRequiresUniqueMatch：多个匹配默认必须报错，不能像以前那样静默改第一个。
func TestEditRequiresUniqueMatch(t *testing.T) {
	_, err := editIn(t, "foo\nbar\nfoo\n", `{"path":"PATH","old_string":"foo","new_string":"x"}`)
	if err == nil {
		t.Fatal("multiple matches must fail without replace_all")
	}
	if !strings.Contains(err.Error(), "2 times") || !strings.Contains(err.Error(), "replace_all") {
		t.Fatalf("error should name the count and the escape hatch, got %q", err)
	}
}

func TestEditReplaceAll(t *testing.T) {
	got, err := editIn(t, "foo\nbar\nfoo\n", `{"path":"PATH","old_string":"foo","new_string":"x","replace_all":true}`)
	if err != nil {
		t.Fatal(err)
	}
	if got != "x\nbar\nx\n" {
		t.Fatalf("got %q", got)
	}
}

func TestEditUniqueReplacement(t *testing.T) {
	got, err := editIn(t, "alpha beta gamma\n", `{"path":"PATH","old_string":"beta","new_string":"B"}`)
	if err != nil {
		t.Fatal(err)
	}
	if got != "alpha B gamma\n" {
		t.Fatalf("got %q", got)
	}
}

// TestEditNormalizesTypographicCharacters：模型从网页复制的弯引号/破折号，
// 用 ASCII 也能命中；写回后文件里是 new_string 的原始字节。
func TestEditNormalizesTypographicCharacters(t *testing.T) {
	got, err := editIn(t, "say “hello” — now\n", `{"path":"PATH","old_string":"say \"hello\" - now","new_string":"say \"bye\" - later"}`)
	if err != nil {
		t.Fatal(err)
	}
	if got != "say \"bye\" - later\n" {
		t.Fatalf("got %q", got)
	}
}

// TestEditIgnoresTrailingWhitespace：行尾多/少空格时退到逐行匹配，
// 且替换后不把旧行的多余空白带回来。
func TestEditIgnoresTrailingWhitespace(t *testing.T) {
	got, err := editIn(t, "a  \nb\t\nc\n", `{"path":"PATH","old_string":"a\nb\n","new_string":"x\ny\n"}`)
	if err != nil {
		t.Fatal(err)
	}
	if got != "x\ny\nc\n" {
		t.Fatalf("got %q", got)
	}
}

// TestEditPreservesCRLF：命中 CRLF 区域时，LF 风格的 new_string 要转成 CRLF。
func TestEditPreservesCRLF(t *testing.T) {
	got, err := editIn(t, "one\r\ntwo\r\nthree\r\n", `{"path":"PATH","old_string":"one\ntwo","new_string":"1\n2"}`)
	if err != nil {
		t.Fatal(err)
	}
	if got != "1\r\n2\r\nthree\r\n" {
		t.Fatalf("got %q", got)
	}
}

func TestEditNotFound(t *testing.T) {
	_, err := editIn(t, "abc\n", `{"path":"PATH","old_string":"zzz","new_string":"x"}`)
	if err == nil || !strings.Contains(err.Error(), "not found") {
		t.Fatalf("want not-found error, got %v", err)
	}
}

func TestEditRejectsEmptyOldString(t *testing.T) {
	_, err := editIn(t, "abc\n", `{"path":"PATH","old_string":"","new_string":"x"}`)
	if err == nil || !strings.Contains(err.Error(), "must not be empty") {
		t.Fatalf("want empty-old-string error, got %v", err)
	}
}

// TestEditAmbiguousDoesNotRecordSnapshot：失败的编辑不能留档。
func TestEditAmbiguousDoesNotRecordSnapshot(t *testing.T) {
	dir := t.TempDir()
	snap := &recordingSnap{}
	reg := NewRegistry()
	for _, tl := range BuiltinIn(dir, NewFence(), snap) {
		if err := reg.Register(tl); err != nil {
			t.Fatal(err)
		}
	}
	e, _ := reg.Get("edit")
	p := filepath.Join(dir, "s.txt")
	if err := os.WriteFile(p, []byte("x x"), 0o644); err != nil {
		t.Fatal(err)
	}
	if _, err := e.Run(context.Background(),
		`{"path":"`+p+`","old_string":"x","new_string":"y"}`); err == nil {
		t.Fatal("ambiguous edit must fail")
	}
	if len(snap.got) != 0 {
		t.Fatalf("failed edit recorded a snapshot: %+v", snap.got)
	}
}