package herdr

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

func TestClaudeStopHookUsage(t *testing.T) {
	// The hook parser's path validation is independent from transcript IO.
	_, path, err := ClaudeStopHookUsage(strings.NewReader(`{"transcript_path":"/tmp/transcript.jsonl"}`))
	if path != "/tmp/transcript.jsonl" || err == nil {
		t.Fatalf("path=%q err=%v", path, err)
	}
}

func TestCodexRolloutFallback(t *testing.T) {
	paths, err := CodexRolloutPaths(t.TempDir())
	if err == nil || len(paths) != 0 {
		t.Fatalf("paths=%v err=%v", paths, err)
	}
}

// TestClaudeUsageIsLastTurnNotCumulative guards the exact trap the spec
// (§5.2.1) calls out by name: occupancy must reflect the current context
// window (the last turn's usage snapshot), not a running total across many
// turns. A transcript with one huge early turn and a small final turn must
// report low occupancy, because Claude Code's own usage lines are already
// cumulative-per-turn snapshots, not deltas to be summed.
func TestClaudeUsageIsLastTurnNotCumulative(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "transcript.jsonl")
	lines := []string{
		`{"message":{"usage":{"input_tokens":180000,"cache_read_input_tokens":0,"cache_creation_input_tokens":0,"output_tokens":500}}}`,
		`{"message":{"usage":{"input_tokens":2000,"cache_read_input_tokens":500,"cache_creation_input_tokens":0,"output_tokens":100}}}`,
	}
	if err := os.WriteFile(path, []byte(strings.Join(lines, "\n")+"\n"), 0644); err != nil {
		t.Fatal(err)
	}
	u, err := ClaudeUsage(path)
	if err != nil {
		t.Fatal(err)
	}
	frac := Fraction(u, 200000)
	if frac > 0.05 {
		t.Fatalf("occupancy=%v, want low (last-turn usage, not the 180000-token first turn)", frac)
	}
}

func TestClaudeSessionFileNewestByMtime(t *testing.T) {
	worktree := t.TempDir()
	home := t.TempDir()
	t.Setenv("HOME", home)
	abs, err := filepath.Abs(worktree)
	if err != nil {
		t.Fatal(err)
	}
	enc := strings.ReplaceAll(abs, "/", "-")
	dir := filepath.Join(home, ".claude", "projects", enc)
	if err := os.MkdirAll(dir, 0755); err != nil {
		t.Fatal(err)
	}
	old := filepath.Join(dir, "old.jsonl")
	newer := filepath.Join(dir, "new.jsonl")
	if err := os.WriteFile(old, []byte("{}\n"), 0644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(newer, []byte("{}\n"), 0644); err != nil {
		t.Fatal(err)
	}
	now := time.Now()
	if err := os.Chtimes(old, now.Add(-time.Hour), now.Add(-time.Hour)); err != nil {
		t.Fatal(err)
	}
	if err := os.Chtimes(newer, now, now); err != nil {
		t.Fatal(err)
	}
	got, err := ClaudeSessionFile(worktree)
	if err != nil {
		t.Fatal(err)
	}
	if got != newer {
		t.Fatalf("got %s, want newest transcript %s", got, newer)
	}
}

func TestClaudeSessionFileMissingIsHardError(t *testing.T) {
	worktree := t.TempDir()
	t.Setenv("HOME", t.TempDir())
	if _, err := ClaudeSessionFile(worktree); err == nil {
		t.Fatal("expected error for missing session transcript directory, got nil")
	}
}