package executor

import (
	"context"
	"errors"
	"io"
	"log/slog"
	"os"
	"os/exec"
	"path/filepath"
	"runtime"
	"strings"
	"testing"
	"time"

	"github.com/thepeterstone/claudomator/internal/storage"
	"github.com/thepeterstone/claudomator/internal/task"
)

func TestClaudeRunner_BuildArgs_BasicTask(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "fix the bug",
			Model:        "sonnet",
			SkipPlanning: true,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	argMap := make(map[string]bool)
	for _, a := range args {
		argMap[a] = true
	}
	for _, want := range []string{"-p", "fix the bug", "--output-format", "stream-json", "--verbose", "--model", "sonnet"} {
		if !argMap[want] {
			t.Errorf("missing arg %q in %v", want, args)
		}
	}
}

func TestClaudeRunner_BuildArgs_FullConfig(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:               "claude",
			Instructions:       "implement feature",
			Model:              "opus",
			MaxBudgetUSD:       5.0,
			PermissionMode:     "bypassPermissions",
			SystemPromptAppend: "Follow TDD",
			AllowedTools:       []string{"Bash", "Edit"},
			DisallowedTools:    []string{"Write"},
			ContextFiles:       []string{"/src"},
			AdditionalArgs:     []string{"--verbose"},
			SkipPlanning:       true,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	// Check key args are present.
	argMap := make(map[string]bool)
	for _, a := range args {
		argMap[a] = true
	}

	requiredArgs := []string{
		"-p", "implement feature", "--output-format", "stream-json",
		"--model", "opus", "--max-budget-usd", "5.00",
		"--permission-mode", "bypassPermissions",
		"--append-system-prompt", "Follow TDD",
		"--allowedTools", "Bash", "Edit",
		"--disallowedTools", "Write",
		"--add-dir", "/src",
		"--verbose",
	}
	for _, req := range requiredArgs {
		if !argMap[req] {
			t.Errorf("missing arg %q in %v", req, args)
		}
	}
}

func TestClaudeRunner_BuildArgs_DefaultsToBypassPermissions(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "do work",
			SkipPlanning: true,
			// PermissionMode intentionally not set
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	found := false
	for i, a := range args {
		if a == "--permission-mode" && i+1 < len(args) && args[i+1] == "bypassPermissions" {
			found = true
		}
	}
	if !found {
		t.Errorf("expected --permission-mode bypassPermissions when PermissionMode is empty, args: %v", args)
	}
}

func TestClaudeRunner_BuildArgs_RespectsExplicitPermissionMode(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:           "claude",
			Instructions:   "do work",
			PermissionMode: "default",
			SkipPlanning:   true,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	for i, a := range args {
		if a == "--permission-mode" && i+1 < len(args) {
			if args[i+1] != "default" {
				t.Errorf("expected --permission-mode default, got %q", args[i+1])
			}
			return
		}
	}
	t.Errorf("--permission-mode flag not found in args: %v", args)
}

func TestClaudeRunner_BuildArgs_AlwaysIncludesVerbose(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "do something",
			SkipPlanning: true,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	found := false
	for _, a := range args {
		if a == "--verbose" {
			found = true
			break
		}
	}
	if !found {
		t.Errorf("--verbose missing from args: %v", args)
	}
}

func TestClaudeRunner_BuildArgs_PreamblePrepended(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "fix the bug",
			SkipPlanning: false,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	// The -p value should start with the preamble and end with the original instructions.
	if len(args) < 2 || args[0] != "-p" {
		t.Fatalf("expected -p as first arg, got: %v", args)
	}
	if !strings.HasPrefix(args[1], planningPreamble) {
		t.Errorf("instructions should start with planning preamble")
	}
	if !strings.HasSuffix(args[1], "fix the bug") {
		t.Errorf("instructions should end with original instructions")
	}
}

func TestClaudeRunner_BuildArgs_PreambleAddsBash(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "do work",
			AllowedTools: []string{"Read"},
			SkipPlanning: false,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	// Bash should be appended to allowed tools.
	foundBash := false
	for i, a := range args {
		if a == "--allowedTools" && i+1 < len(args) && args[i+1] == "Bash" {
			foundBash = true
		}
	}
	if !foundBash {
		t.Errorf("Bash should be added to --allowedTools when preamble is active: %v", args)
	}
}

func TestClaudeRunner_BuildArgs_PreambleBashNotDuplicated(t *testing.T) {
	r := &ClaudeRunner{}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "do work",
			AllowedTools: []string{"Bash", "Read"},
			SkipPlanning: false,
		},
	}

	args := r.buildArgs(tk, &storage.Execution{ID: "test-exec"}, "/tmp/q.json")

	// Count Bash occurrences in --allowedTools values.
	bashCount := 0
	for i, a := range args {
		if a == "--allowedTools" && i+1 < len(args) && args[i+1] == "Bash" {
			bashCount++
		}
	}
	if bashCount != 1 {
		t.Errorf("Bash should appear exactly once in --allowedTools, got %d: %v", bashCount, args)
	}
}

// TestClaudeRunner_Run_ResumeSetsSessionIDFromResumeSession verifies that when a
// resume execution is itself blocked again, the stored SessionID is the original
// resumed session, not the new execution's own UUID. Without this, a second
// block-and-resume cycle passes the wrong --resume session ID and fails.
func TestClaudeRunner_Run_ResumeSetsSessionIDFromResumeSession(t *testing.T) {
	logDir := t.TempDir()
	r := &ClaudeRunner{
		BinaryPath: "true", // exits 0, no output
		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
		LogDir:     logDir,
	}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "continue",
			SkipPlanning: true,
		},
	}
	exec := &storage.Execution{
		ID:              "resume-exec-uuid",
		TaskID:          "task-1",
		ResumeSessionID: "original-session-uuid",
		ResumeAnswer:    "yes",
	}

	// Run completes successfully (binary is "true").
	_ = r.Run(context.Background(), tk, exec)

	// SessionID must be the original session (ResumeSessionID), not the new
	// exec's own ID. If it were exec.ID, a second blocked-then-resumed cycle
	// would use the wrong --resume argument and fail.
	if exec.SessionID != "original-session-uuid" {
		t.Errorf("SessionID after resume Run: want %q, got %q", "original-session-uuid", exec.SessionID)
	}
}

func TestClaudeRunner_Run_InaccessibleWorkingDir_ReturnsError(t *testing.T) {
	r := &ClaudeRunner{
		BinaryPath: "true", // would succeed if it ran
		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
		LogDir:     t.TempDir(),
	}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			ProjectDir:   "/nonexistent/path/does/not/exist",
			SkipPlanning: true,
		},
	}
	exec := &storage.Execution{ID: "test-exec"}

	err := r.Run(context.Background(), tk, exec)

	if err == nil {
		t.Fatal("expected error for inaccessible working_dir, got nil")
	}
	if !strings.Contains(err.Error(), "project_dir") {
		t.Errorf("expected 'project_dir' in error, got: %v", err)
	}
}

func TestClaudeRunner_BinaryPath_Default(t *testing.T) {
	r := &ClaudeRunner{}
	if r.binaryPath() != "claude" {
		t.Errorf("want 'claude', got %q", r.binaryPath())
	}
}

func TestClaudeRunner_BinaryPath_Custom(t *testing.T) {
	r := &ClaudeRunner{BinaryPath: "/usr/local/bin/claude"}
	if r.binaryPath() != "/usr/local/bin/claude" {
		t.Errorf("want custom path, got %q", r.binaryPath())
	}
}

// TestExecOnce_NoGoroutineLeak_OnNaturalExit verifies that execOnce does not
// leave behind any goroutines when the subprocess exits normally (no context
// cancellation). Both the pgid-kill goroutine and the parseStream goroutine
// must have exited before execOnce returns.
func TestExecOnce_NoGoroutineLeak_OnNaturalExit(t *testing.T) {
	logDir := t.TempDir()
	r := &ClaudeRunner{
		BinaryPath: "true", // exits immediately with status 0, produces no output
		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
		LogDir:     logDir,
	}
	e := &storage.Execution{
		ID:          "goroutine-leak-test",
		TaskID:      "task-id",
		StdoutPath:  filepath.Join(logDir, "stdout.log"),
		StderrPath:  filepath.Join(logDir, "stderr.log"),
		ArtifactDir: logDir,
	}

	// Let any goroutines from test infrastructure settle before sampling.
	runtime.Gosched()
	baseline := runtime.NumGoroutine()

	if err := r.execOnce(context.Background(), []string{}, "", e); err != nil {
		t.Fatalf("execOnce failed: %v", err)
	}

	// Give the scheduler a moment to let any leaked goroutines actually exit.
	// In correct code the goroutines exit before execOnce returns, so this is
	// just a safety buffer for the scheduler.
	time.Sleep(10 * time.Millisecond)
	runtime.Gosched()

	after := runtime.NumGoroutine()
	if after > baseline {
		t.Errorf("goroutine leak: %d goroutines before execOnce, %d after (leaked %d)",
			baseline, after, after-baseline)
	}
}

// initGitRepo creates a git repo in dir with one commit so it is clonable.
func initGitRepo(t *testing.T, dir string) {
	t.Helper()
	cmds := [][]string{
		{"git", "-C", dir, "init"},
		{"git", "-C", dir, "config", "user.email", "test@test"},
		{"git", "-C", dir, "config", "user.name", "test"},
		{"git", "-C", dir, "commit", "--allow-empty", "-m", "init"},
	}
	for _, args := range cmds {
		if out, err := exec.Command(args[0], args[1:]...).CombinedOutput(); err != nil {
			t.Fatalf("%v: %v\n%s", args, err, out)
		}
	}
}

func TestSandboxCloneSource_PrefersLocalRemote(t *testing.T) {
	dir := t.TempDir()
	initGitRepo(t, dir)
	// Add a "local" remote pointing to a bare repo.
	bare := t.TempDir()
	exec.Command("git", "init", "--bare", bare).Run()
	exec.Command("git", "-C", dir, "remote", "add", "local", bare).Run()
	exec.Command("git", "-C", dir, "remote", "add", "origin", "https://example.com/repo").Run()

	got := sandboxCloneSource(dir)
	if got != bare {
		t.Errorf("expected bare repo path %q, got %q", bare, got)
	}
}

func TestSandboxCloneSource_FallsBackToOrigin(t *testing.T) {
	dir := t.TempDir()
	initGitRepo(t, dir)
	originURL := "https://example.com/origin-repo"
	exec.Command("git", "-C", dir, "remote", "add", "origin", originURL).Run()

	got := sandboxCloneSource(dir)
	if got != originURL {
		t.Errorf("expected origin URL %q, got %q", originURL, got)
	}
}

func TestSandboxCloneSource_FallsBackToProjectDir(t *testing.T) {
	dir := t.TempDir()
	initGitRepo(t, dir)
	// No remotes configured.
	got := sandboxCloneSource(dir)
	if got != dir {
		t.Errorf("expected projectDir %q (no remotes), got %q", dir, got)
	}
}

func TestSetupSandbox_ClonesGitRepo(t *testing.T) {
	src := t.TempDir()
	initGitRepo(t, src)

	sandbox, err := setupSandbox(src)
	if err != nil {
		t.Fatalf("setupSandbox: %v", err)
	}
	t.Cleanup(func() { os.RemoveAll(sandbox) })

	// Verify sandbox is a git repo with at least one commit.
	out, err := exec.Command("git", "-C", sandbox, "log", "--oneline").Output()
	if err != nil {
		t.Fatalf("git log in sandbox: %v", err)
	}
	if len(strings.TrimSpace(string(out))) == 0 {
		t.Error("expected at least one commit in sandbox, got empty log")
	}
}

func TestSetupSandbox_InitialisesNonGitDir(t *testing.T) {
	// A plain directory (not a git repo) should be initialised then cloned.
	src := t.TempDir()

	sandbox, err := setupSandbox(src)
	if err != nil {
		t.Fatalf("setupSandbox on plain dir: %v", err)
	}
	t.Cleanup(func() { os.RemoveAll(sandbox) })

	if _, err := os.Stat(filepath.Join(sandbox, ".git")); err != nil {
		t.Errorf("sandbox should be a git repo: %v", err)
	}
}

func TestTeardownSandbox_UncommittedChanges_ReturnsError(t *testing.T) {
	src := t.TempDir()
	initGitRepo(t, src)
	sandbox, err := setupSandbox(src)
	if err != nil {
		t.Fatalf("setupSandbox: %v", err)
	}
	t.Cleanup(func() { os.RemoveAll(sandbox) })

	// Leave an uncommitted file in the sandbox.
	if err := os.WriteFile(filepath.Join(sandbox, "dirty.txt"), []byte("oops"), 0644); err != nil {
		t.Fatal(err)
	}

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
	err = teardownSandbox(src, sandbox, logger)
	if err == nil {
		t.Fatal("expected error for uncommitted changes, got nil")
	}
	if !strings.Contains(err.Error(), "uncommitted changes") {
		t.Errorf("expected 'uncommitted changes' in error, got: %v", err)
	}
	// Sandbox should be preserved (not removed) on error.
	if _, statErr := os.Stat(sandbox); os.IsNotExist(statErr) {
		t.Error("sandbox was removed despite error; should be preserved for debugging")
	}
}

func TestTeardownSandbox_CleanSandboxWithNoNewCommits_RemovesSandbox(t *testing.T) {
	src := t.TempDir()
	initGitRepo(t, src)
	sandbox, err := setupSandbox(src)
	if err != nil {
		t.Fatalf("setupSandbox: %v", err)
	}

	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
	// Sandbox has no new commits beyond origin; teardown should succeed and remove it.
	if err := teardownSandbox(src, sandbox, logger); err != nil {
		t.Fatalf("teardownSandbox: %v", err)
	}
	if _, statErr := os.Stat(sandbox); !os.IsNotExist(statErr) {
		t.Error("sandbox should have been removed after clean teardown")
		os.RemoveAll(sandbox)
	}
}

// TestBlockedError_IncludesSandboxDir verifies that when a task is blocked in a
// sandbox, the BlockedError carries the sandbox path so the resume execution can
// run in the same directory (where Claude's session files are stored).
func TestBlockedError_IncludesSandboxDir(t *testing.T) {
	src := t.TempDir()
	initGitRepo(t, src)

	logDir := t.TempDir()

	// Use a script that writes question.json to the env-var path and exits 0
	// (simulating a blocked agent that asks a question before exiting).
	scriptPath := filepath.Join(t.TempDir(), "fake-claude.sh")
	if err := os.WriteFile(scriptPath, []byte(`#!/bin/sh
if [ -n "$CLAUDOMATOR_QUESTION_FILE" ]; then
  printf '{"question":"continue?"}' > "$CLAUDOMATOR_QUESTION_FILE"
fi
`), 0755); err != nil {
		t.Fatalf("write script: %v", err)
	}

	r := &ClaudeRunner{
		BinaryPath: scriptPath,
		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
		LogDir:     logDir,
	}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			Instructions: "do something",
			ProjectDir:   src,
			SkipPlanning: true,
		},
	}
	exec := &storage.Execution{ID: "blocked-exec-uuid", TaskID: "task-1"}

	err := r.Run(context.Background(), tk, exec)

	var blocked *BlockedError
	if !errors.As(err, &blocked) {
		t.Fatalf("expected BlockedError, got: %v", err)
	}
	if blocked.SandboxDir == "" {
		t.Error("BlockedError.SandboxDir should be set when task runs in a sandbox")
	}
	// Sandbox should still exist (preserved for resume).
	if _, statErr := os.Stat(blocked.SandboxDir); os.IsNotExist(statErr) {
		t.Error("sandbox directory should be preserved when blocked")
	} else {
		os.RemoveAll(blocked.SandboxDir) // cleanup
	}
}

// TestClaudeRunner_Run_ResumeUsesStoredSandboxDir verifies that when a resume
// execution has SandboxDir set, the runner uses that directory (not project_dir)
// as the working directory, so Claude finds its session files there.
func TestClaudeRunner_Run_ResumeUsesStoredSandboxDir(t *testing.T) {
	logDir := t.TempDir()
	sandboxDir := t.TempDir()
	cwdFile := filepath.Join(logDir, "cwd.txt")

	// Use a script that writes its working directory to a file in logDir (stable path).
	scriptPath := filepath.Join(t.TempDir(), "fake-claude.sh")
	script := "#!/bin/sh\nprintf '%s' \"$PWD\" > " + cwdFile + "\n"
	if err := os.WriteFile(scriptPath, []byte(script), 0755); err != nil {
		t.Fatalf("write script: %v", err)
	}

	r := &ClaudeRunner{
		BinaryPath: scriptPath,
		Logger:     slog.New(slog.NewTextHandler(io.Discard, nil)),
		LogDir:     logDir,
	}
	tk := &task.Task{
		Agent: task.AgentConfig{
			Type:         "claude",
			ProjectDir:   sandboxDir, // must exist; resume overrides it with SandboxDir anyway
			SkipPlanning: true,
		},
	}
	exec := &storage.Execution{
		ID:              "resume-exec-uuid",
		TaskID:          "task-1",
		ResumeSessionID: "original-session",
		ResumeAnswer:    "yes",
		SandboxDir:      sandboxDir,
	}

	_ = r.Run(context.Background(), tk, exec)

	got, err := os.ReadFile(cwdFile)
	if err != nil {
		t.Fatalf("cwd file not written: %v", err)
	}
	// The runner should have executed claude in sandboxDir, not in project_dir.
	if string(got) != sandboxDir {
		t.Errorf("resume working dir: want %q, got %q", sandboxDir, string(got))
	}
}