package tools

import (
	"context"
	"encoding/json"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"[[.SDKModule]]/pluginsdk"
)

// fakeHost answers host.files.* for files inside dir, like Cletus does for
// the folder the user opened.
func fakeHost(dir string, canWrite bool) *pluginsdk.Host {
	return pluginsdk.NewTestHost(func(method string, params json.RawMessage) (any, error) {
		var p struct{ Path string }
		_ = json.Unmarshal(params, &p)
		path := p.Path
		if !filepath.IsAbs(path) {
			path = filepath.Join(dir, path)
		}
		switch method {
		case "host.files.resolve":
			if _, err := os.Stat(path); err != nil {
				return nil, errors.New(p.Path + " does not exist")
			}
			return path, nil
		case "host.files.can_write":
			return canWrite, nil
		}
		return nil, errors.New("unexpected host call " + method)
	})
}

func run(t *testing.T, tool pluginsdk.Tool, h *pluginsdk.Host, args string, edit bool) pluginsdk.ToolResult {
	t.Helper()
	return tool.Run(context.Background(), h, pluginsdk.ToolCall{Args: json.RawMessage(args), EditMode: edit})
}

func TestCountLines(t *testing.T) {
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, "a.txt"), []byte("one\ntwo\nthree"), 0o644); err != nil {
		t.Fatal(err)
	}
	got := run(t, countLines, fakeHost(dir, false), `{"path":"a.txt"}`, false)
	if got.Error != "" || !strings.Contains(got.Text, "3 lines") {
		t.Fatalf("got %+v", got)
	}
	if got := run(t, countLines, fakeHost(dir, false), `{"path":"missing.txt"}`, false); got.Error == "" {
		t.Fatal("a missing file should fail")
	}
}

func TestSaveSummaryNeedsEdits(t *testing.T) {
	dir := t.TempDir()
	if err := os.WriteFile(filepath.Join(dir, "a.txt"), []byte("one\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	if got := run(t, saveSummary, fakeHost(dir, false), `{"path":"a.txt"}`, false); got.Error == "" {
		t.Fatal("saving without edits allowed should fail")
	}
	got := run(t, saveSummary, fakeHost(dir, true), `{"path":"a.txt"}`, true)
	if got.Error != "" {
		t.Fatalf("got %+v", got)
	}
	data, err := os.ReadFile(filepath.Join(dir, "a.txt.summary.txt"))
	if err != nil || string(data) != "1 lines\n" {
		t.Fatalf("summary = %q, %v", data, err)
	}
}