package executor

import (
	"context"
	"io"
	"log/slog"
	"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)
	}
}

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)
	}
}