package api

import (
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"sync/atomic"
	"testing"
	"time"

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

// mockTaskLogStore implements taskLogStore for testing handleStreamTaskLogs.
type mockTaskLogStore struct {
	getExecution       func(id string) (*storage.Execution, error)
	getLatestExecution func(taskID string) (*storage.Execution, error)
}

func (m *mockTaskLogStore) GetExecution(id string) (*storage.Execution, error) {
	return m.getExecution(id)
}

func (m *mockTaskLogStore) GetLatestExecution(taskID string) (*storage.Execution, error) {
	return m.getLatestExecution(taskID)
}

func taskLogsMux(srv *Server) *http.ServeMux {
	mux := http.NewServeMux()
	mux.HandleFunc("GET /api/tasks/{id}/logs/stream", srv.handleStreamTaskLogs)
	return mux
}

// mockLogStore implements logStore for testing.
type mockLogStore struct {
	fn func(id string) (*storage.Execution, error)
}

func (m *mockLogStore) GetExecution(id string) (*storage.Execution, error) {
	return m.fn(id)
}

func logsMux(srv *Server) *http.ServeMux {
	mux := http.NewServeMux()
	mux.HandleFunc("GET /api/executions/{id}/logs", srv.handleStreamLogs)
	return mux
}

// TestHandleStreamLogs_NotFound verifies that an unknown execution ID yields 404.
func TestHandleStreamLogs_NotFound(t *testing.T) {
	srv := &Server{
		logStore: &mockLogStore{fn: func(id string) (*storage.Execution, error) {
			return nil, errors.New("not found")
		}},
	}

	req := httptest.NewRequest("GET", "/api/executions/nonexistent/logs", nil)
	w := httptest.NewRecorder()
	logsMux(srv).ServeHTTP(w, req)

	if w.Code != http.StatusNotFound {
		t.Errorf("status: want 404, got %d; body: %s", w.Code, w.Body.String())
	}
}

// TestHandleStreamLogs_TerminalState_EmitsEventsAndDone verifies that a COMPLETED
// execution with a populated stdout.log streams SSE events and terminates with a done event.
func TestHandleStreamLogs_TerminalState_EmitsEventsAndDone(t *testing.T) {
	dir := t.TempDir()
	logPath := filepath.Join(dir, "stdout.log")
	lines := strings.Join([]string{
		`{"type":"assistant","message":{"content":[{"type":"text","text":"Hello world"}]}}`,
		`{"type":"assistant","message":{"content":[{"type":"tool_use","name":"Bash","input":{"command":"ls"}}]}}`,
		`{"type":"result","cost_usd":0.0042}`,
	}, "\n") + "\n"
	if err := os.WriteFile(logPath, []byte(lines), 0600); err != nil {
		t.Fatal(err)
	}

	exec := &storage.Execution{
		ID:         "exec-terminal-1",
		TaskID:     "task-terminal-1",
		StartTime:  time.Now(),
		Status:     "COMPLETED",
		StdoutPath: logPath,
	}
	srv := &Server{
		logStore: &mockLogStore{fn: func(id string) (*storage.Execution, error) {
			return exec, nil
		}},
	}

	req := httptest.NewRequest("GET", "/api/executions/exec-terminal-1/logs", nil)
	w := httptest.NewRecorder()
	logsMux(srv).ServeHTTP(w, req)

	if ct := w.Header().Get("Content-Type"); !strings.HasPrefix(ct, "text/event-stream") {
		t.Errorf("Content-Type: want text/event-stream, got %q", ct)
	}
	body := w.Body.String()
	if !strings.Contains(body, "data: ") {
		t.Error("expected at least one SSE 'data: ' event in body")
	}
	if !strings.Contains(body, "\n\n") {
		t.Error("expected SSE double-newline event termination")
	}
	if !strings.HasSuffix(body, "event: done\ndata: {}\n\n") {
		t.Errorf("body does not end with done event; got:\n%s", body)
	}
}

// TestHandleStreamLogs_EmptyLog verifies that a COMPLETED execution with no stdout path
// responds with only the done sentinel event.
func TestHandleStreamLogs_EmptyLog(t *testing.T) {
	exec := &storage.Execution{
		ID:        "exec-empty-1",
		TaskID:    "task-empty-1",
		StartTime: time.Now(),
		Status:    "COMPLETED",
		// StdoutPath intentionally empty
	}
	srv := &Server{
		logStore: &mockLogStore{fn: func(id string) (*storage.Execution, error) {
			return exec, nil
		}},
	}

	req := httptest.NewRequest("GET", "/api/executions/exec-empty-1/logs", nil)
	w := httptest.NewRecorder()
	logsMux(srv).ServeHTTP(w, req)

	body := w.Body.String()
	if body != "event: done\ndata: {}\n\n" {
		t.Errorf("want only done event, got:\n%s", body)
	}
}

// TestHandleStreamLogs_RunningState_LiveTail verifies that a RUNNING execution streams
// initial log content and emits a done event once it transitions to a terminal state.
func TestHandleStreamLogs_RunningState_LiveTail(t *testing.T) {
	dir := t.TempDir()
	logPath := filepath.Join(dir, "stdout.log")
	logLines := strings.Join([]string{
		`{"type":"assistant","message":{"content":[{"type":"text","text":"Working..."}]}}`,
		`{"type":"result","cost_usd":0.001}`,
	}, "\n") + "\n"
	if err := os.WriteFile(logPath, []byte(logLines), 0600); err != nil {
		t.Fatal(err)
	}

	runningExec := &storage.Execution{
		ID:         "exec-running-1",
		TaskID:     "task-running-1",
		StartTime:  time.Now(),
		Status:     "RUNNING",
		StdoutPath: logPath,
	}

	// callCount tracks how many times GetExecution has been called.
	// Call 1: initial fetch in handleStreamLogs → RUNNING
	// Call 2+: poll in tailRunningExecution → COMPLETED
	var callCount atomic.Int32
	mock := &mockLogStore{fn: func(id string) (*storage.Execution, error) {
		n := callCount.Add(1)
		if n <= 1 {
			return runningExec, nil
		}
		completed := *runningExec
		completed.Status = "COMPLETED"
		return &completed, nil
	}}

	srv := &Server{logStore: mock}

	req := httptest.NewRequest("GET", "/api/executions/exec-running-1/logs", nil)
	w := httptest.NewRecorder()
	logsMux(srv).ServeHTTP(w, req)

	body := w.Body.String()
	if !strings.Contains(body, `"Working..."`) {
		t.Errorf("expected initial text event in body; got:\n%s", body)
	}
	if !strings.Contains(body, `"type":"cost"`) {
		t.Errorf("expected cost event in body; got:\n%s", body)
	}
	if !strings.HasSuffix(body, "event: done\ndata: {}\n\n") {
		t.Errorf("body does not end with done event; got:\n%s", body)
	}
}

// --- Task-level SSE log streaming tests (handleStreamTaskLogs) ---

// TestHandleStreamTaskLogs_TaskNotFound verifies that a task with no executions yields 404.
func TestHandleStreamTaskLogs_TaskNotFound(t *testing.T) {
	srv := &Server{
		taskLogStore: &mockTaskLogStore{
			getLatestExecution: func(taskID string) (*storage.Execution, error) {
				return nil, errors.New("not found")
			},
		},
	}

	req := httptest.NewRequest("GET", "/api/tasks/nonexistent/logs/stream", nil)
	w := httptest.NewRecorder()
	taskLogsMux(srv).ServeHTTP(w, req)

	if w.Code != http.StatusNotFound {
		t.Errorf("status: want 404, got %d; body: %s", w.Code, w.Body.String())
	}
}

// TestHandleStreamTaskLogs_NoStdoutPath_EmitsDone verifies that a completed execution with no
// stdout log path emits only the done sentinel event.
func TestHandleStreamTaskLogs_NoStdoutPath_EmitsDone(t *testing.T) {
	exec := &storage.Execution{
		ID:        "exec-task-empty",
		TaskID:    "task-no-log",
		StartTime: time.Now(),
		Status:    "COMPLETED",
		// StdoutPath intentionally empty
	}
	srv := &Server{
		taskLogStore: &mockTaskLogStore{
			getLatestExecution: func(taskID string) (*storage.Execution, error) {
				return exec, nil
			},
			getExecution: func(id string) (*storage.Execution, error) {
				return exec, nil
			},
		},
	}

	req := httptest.NewRequest("GET", "/api/tasks/task-no-log/logs/stream", nil)
	w := httptest.NewRecorder()
	taskLogsMux(srv).ServeHTTP(w, req)

	if ct := w.Header().Get("Content-Type"); !strings.HasPrefix(ct, "text/event-stream") {
		t.Errorf("Content-Type: want text/event-stream, got %q", ct)
	}
	body := w.Body.String()
	if body != "event: done\ndata: {}\n\n" {
		t.Errorf("want only done event, got:\n%s", body)
	}
}

// TestHandleStreamTaskLogs_TerminalExecution_EmitsEventsAndDone verifies that a COMPLETED
// execution streams SSE events and ends with a done event.
func TestHandleStreamTaskLogs_TerminalExecution_EmitsEventsAndDone(t *testing.T) {
	dir := t.TempDir()
	logPath := filepath.Join(dir, "stdout.log")
	lines := strings.Join([]string{
		`{"type":"assistant","message":{"content":[{"type":"text","text":"Task output here"}]}}`,
		`{"type":"result","cost_usd":0.007}`,
	}, "\n") + "\n"
	if err := os.WriteFile(logPath, []byte(lines), 0600); err != nil {
		t.Fatal(err)
	}

	exec := &storage.Execution{
		ID:         "exec-task-done",
		TaskID:     "task-done",
		StartTime:  time.Now(),
		Status:     "COMPLETED",
		StdoutPath: logPath,
	}
	srv := &Server{
		taskLogStore: &mockTaskLogStore{
			getLatestExecution: func(taskID string) (*storage.Execution, error) {
				return exec, nil
			},
			getExecution: func(id string) (*storage.Execution, error) {
				return exec, nil
			},
		},
	}

	req := httptest.NewRequest("GET", "/api/tasks/task-done/logs/stream", nil)
	w := httptest.NewRecorder()
	taskLogsMux(srv).ServeHTTP(w, req)

	body := w.Body.String()
	if !strings.Contains(body, `"Task output here"`) {
		t.Errorf("expected text event content in body; got:\n%s", body)
	}
	if !strings.Contains(body, `"type":"cost"`) {
		t.Errorf("expected cost event in body; got:\n%s", body)
	}
	if !strings.HasSuffix(body, "event: done\ndata: {}\n\n") {
		t.Errorf("body does not end with done event; got:\n%s", body)
	}
}

// TestEmitLogLine_ToolUse_EmitsNameField verifies that emitLogLine emits a tool_use SSE event
// with a "name" field matching the tool name so the web UI can display it as "[ToolName]".
func TestEmitLogLine_ToolUse_EmitsNameField(t *testing.T) {
	line := []byte(`{"type":"assistant","message":{"content":[{"type":"tool_use","name":"Bash","input":{"command":"ls -la"}}]}}`)

	w := httptest.NewRecorder()
	emitLogLine(w, w, line)

	body := w.Body.String()
	var found bool
	for _, chunk := range strings.Split(body, "\n\n") {
		chunk = strings.TrimSpace(chunk)
		if !strings.HasPrefix(chunk, "data: ") {
			continue
		}
		jsonStr := strings.TrimPrefix(chunk, "data: ")
		var e map[string]interface{}
		if err := json.Unmarshal([]byte(jsonStr), &e); err != nil {
			continue
		}
		if e["type"] == "tool_use" {
			if e["name"] != "Bash" {
				t.Errorf("tool_use event name: want Bash, got %v", e["name"])
			}
			if e["input"] == nil {
				t.Error("tool_use event input: expected non-nil")
			}
			found = true
		}
	}
	if !found {
		t.Errorf("no tool_use event found in SSE output:\n%s", body)
	}
}

// TestEmitLogLine_Cost_EmitsTotalCostField verifies that emitLogLine emits a cost SSE event
// with a numeric "total_cost" field so the web UI can display it correctly.
func TestEmitLogLine_Cost_EmitsTotalCostField(t *testing.T) {
	line := []byte(`{"type":"result","total_cost_usd":0.0042}`)

	w := httptest.NewRecorder()
	emitLogLine(w, w, line)

	body := w.Body.String()
	var found bool
	for _, chunk := range strings.Split(body, "\n\n") {
		chunk = strings.TrimSpace(chunk)
		if !strings.HasPrefix(chunk, "data: ") {
			continue
		}
		jsonStr := strings.TrimPrefix(chunk, "data: ")
		var e map[string]interface{}
		if err := json.Unmarshal([]byte(jsonStr), &e); err != nil {
			continue
		}
		if e["type"] == "cost" {
			if e["total_cost"] == nil {
				t.Error("cost event total_cost: expected non-nil numeric field")
			}
			if v, ok := e["total_cost"].(float64); !ok || v != 0.0042 {
				t.Errorf("cost event total_cost: want 0.0042, got %v", e["total_cost"])
			}
			found = true
		}
	}
	if !found {
		t.Errorf("no cost event found in SSE output:\n%s", body)
	}
}

// TestHandleStreamTaskLogs_RunningExecution_LiveTails verifies that a RUNNING execution is
// live-tailed and a done event is emitted once it transitions to a terminal state.
func TestHandleStreamTaskLogs_RunningExecution_LiveTails(t *testing.T) {
	dir := t.TempDir()
	logPath := filepath.Join(dir, "stdout.log")
	logLines := strings.Join([]string{
		`{"type":"assistant","message":{"content":[{"type":"text","text":"Still running..."}]}}`,
		`{"type":"result","cost_usd":0.003}`,
	}, "\n") + "\n"
	if err := os.WriteFile(logPath, []byte(logLines), 0600); err != nil {
		t.Fatal(err)
	}

	runningExec := &storage.Execution{
		ID:         "exec-task-running",
		TaskID:     "task-running",
		StartTime:  time.Now(),
		Status:     "RUNNING",
		StdoutPath: logPath,
	}

	// getLatestExecution is called once (initial lookup); getExecution polls for state change.
	var pollCount atomic.Int32
	srv := &Server{
		taskLogStore: &mockTaskLogStore{
			getLatestExecution: func(taskID string) (*storage.Execution, error) {
				return runningExec, nil
			},
			getExecution: func(id string) (*storage.Execution, error) {
				n := pollCount.Add(1)
				if n <= 1 {
					return runningExec, nil
				}
				completed := *runningExec
				completed.Status = "COMPLETED"
				return &completed, nil
			},
		},
	}

	req := httptest.NewRequest("GET", "/api/tasks/task-running/logs/stream", nil)
	w := httptest.NewRecorder()
	taskLogsMux(srv).ServeHTTP(w, req)

	body := w.Body.String()
	if !strings.Contains(body, `"Still running..."`) {
		t.Errorf("expected live-tail text in body; got:\n%s", body)
	}
	if !strings.HasSuffix(body, "event: done\ndata: {}\n\n") {
		t.Errorf("body does not end with done event; got:\n%s", body)
	}
}