//go:build !windows && linux

package infra

import (
	"encoding/json"
	"os"
	"path/filepath"
	"testing"
	"time"
)

// writeJSON marshals v and writes it to path, failing the test on error.
func writeJSON(t *testing.T, path string, v any) {
	t.Helper()
	if err := os.MkdirAll(filepath.Dir(path), 0o755); err != nil {
		t.Fatalf("mkdir %q: %v", filepath.Dir(path), err)
	}
	b, err := json.Marshal(v)
	if err != nil {
		t.Fatalf("marshal: %v", err)
	}
	if err := os.WriteFile(path, b, 0o644); err != nil {
		t.Fatalf("write %q: %v", path, err)
	}
}

// touch sets the mtime of path to the given unix epoch seconds.
func touch(t *testing.T, path string, epoch int64) {
	t.Helper()
	mt := time.Unix(epoch, 0)
	if err := os.Chtimes(path, mt, mt); err != nil {
		t.Fatalf("chtimes %q: %v", path, err)
	}
}

func TestListResumableClaudesFrom(t *testing.T) {
	t.Run("excluye sesion viva, incluye muertas con goal ordenadas por LastActive", func(t *testing.T) {
		dir := t.TempDir()
		sessionsDir := filepath.Join(dir, "sessions")
		goalsDir := filepath.Join(dir, "goals")

		// A LIVE session: real running PID (this test process) + its real
		// /proc starttime as procStart, so procIsAlive returns true.
		livePID := os.Getpid()
		liveStart, ok := procStartTime(livePID)
		if !ok {
			t.Fatalf("could not read procStartTime for self pid %d", livePID)
		}
		const liveSession = "11111111-aaaa-bbbb-cccc-000000000001"
		writeJSON(t, filepath.Join(sessionsDir, "9001.json"), sessionFile{
			PID:       livePID,
			SessionID: liveSession,
			Cwd:       "/tmp/live",
			ProcStart: liveStart,
			Status:    "busy",
		})

		// A goal for the live session: must be EXCLUDED (already in fleet).
		liveGoal := filepath.Join(goalsDir, liveSession+".json")
		writeJSON(t, liveGoal, goalFile{Goal: "trabajo en curso", Emojis: "🔥", Rename: "vivo"})
		touch(t, liveGoal, 5000)

		// A DEAD session with a goal: must be INCLUDED. No sessions/ entry,
		// so it can never be live.
		const deadOld = "22222222-aaaa-bbbb-cccc-000000000002"
		oldGoal := filepath.Join(goalsDir, deadOld+".json")
		writeJSON(t, oldGoal, goalFile{Goal: "objetivo antiguo", Emojis: "🛠️", Rename: "viejo"})
		touch(t, oldGoal, 1000)

		// Another DEAD session with a goal, more recent: must come FIRST.
		const deadNew = "33333333-aaaa-bbbb-cccc-000000000003"
		newGoal := filepath.Join(goalsDir, deadNew+".json")
		writeJSON(t, newGoal, goalFile{Goal: "objetivo reciente", Rename: "nuevo"})
		touch(t, newGoal, 4000)

		// A DEAD session WITHOUT a goal string: must be OMITTED.
		const deadEmpty = "44444444-aaaa-bbbb-cccc-000000000004"
		emptyGoal := filepath.Join(goalsDir, deadEmpty+".json")
		writeJSON(t, emptyGoal, goalFile{Goal: "   ", Emojis: "💤"})
		touch(t, emptyGoal, 6000)

		got, err := ListResumableClaudesFrom(dir)
		if err != nil {
			t.Fatalf("ListResumableClaudesFrom: %v", err)
		}

		if len(got) != 2 {
			t.Fatalf("got %d resumable, want 2: %+v", len(got), got)
		}

		// Order by LastActive desc: deadNew (4000) before deadOld (1000).
		if got[0].SessionID != deadNew {
			t.Errorf("got[0].SessionID = %q, want %q", got[0].SessionID, deadNew)
		}
		if got[1].SessionID != deadOld {
			t.Errorf("got[1].SessionID = %q, want %q", got[1].SessionID, deadOld)
		}

		// Live session must not appear.
		for _, r := range got {
			if r.SessionID == liveSession {
				t.Errorf("live session %q must be excluded", liveSession)
			}
			if r.SessionID == deadEmpty {
				t.Errorf("session without goal %q must be omitted", deadEmpty)
			}
		}

		// Field mapping for the most-recent record.
		if got[0].Goal != "objetivo reciente" {
			t.Errorf("got[0].Goal = %q", got[0].Goal)
		}
		if got[0].Name != "nuevo" {
			t.Errorf("got[0].Name = %q, want \"nuevo\"", got[0].Name)
		}
		if got[0].LastActive != 4000 {
			t.Errorf("got[0].LastActive = %d, want 4000", got[0].LastActive)
		}
		if got[1].Emojis != "🛠️" {
			t.Errorf("got[1].Emojis = %q", got[1].Emojis)
		}
	})

	t.Run("dir de goals inexistente retorna slice vacio sin error", func(t *testing.T) {
		dir := t.TempDir() // no goals/ subdir
		got, err := ListResumableClaudesFrom(dir)
		if err != nil {
			t.Fatalf("unexpected error: %v", err)
		}
		if len(got) != 0 {
			t.Errorf("got %d, want 0", len(got))
		}
	})

	t.Run("cap a 40 resultados mas recientes", func(t *testing.T) {
		dir := t.TempDir()
		goalsDir := filepath.Join(dir, "goals")
		// 50 dead sessions with goals, mtimes 1..50.
		for i := 1; i <= 50; i++ {
			id := uuidLike(i)
			p := filepath.Join(goalsDir, id+".json")
			writeJSON(t, p, goalFile{Goal: "objetivo", Rename: id})
			touch(t, p, int64(i))
		}
		got, err := ListResumableClaudesFrom(dir)
		if err != nil {
			t.Fatalf("ListResumableClaudesFrom: %v", err)
		}
		if len(got) != 40 {
			t.Fatalf("got %d, want 40 (capped)", len(got))
		}
		// Most recent first: LastActive should be 50 then descending.
		if got[0].LastActive != 50 {
			t.Errorf("got[0].LastActive = %d, want 50", got[0].LastActive)
		}
		if got[39].LastActive != 11 {
			t.Errorf("got[39].LastActive = %d, want 11", got[39].LastActive)
		}
	})
}

// uuidLike builds a deterministic, unique filename stem for index i.
func uuidLike(i int) string {
	const hex = "0123456789abcdef"
	b := []byte("00000000-0000-0000-0000-000000000000")
	// Fill the last 3 chars with i (i <= 50 fits in 2 hex digits, keep simple).
	b[len(b)-1] = hex[i%16]
	b[len(b)-2] = hex[(i/16)%16]
	b[len(b)-3] = hex[(i/256)%16]
	return string(b)
}