package server

import (
	"fmt"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"sync"
	"time"

	"github.com/gin-gonic/gin"
)

// taskSession represents a PTY session tied to a specific task.
type taskSession struct {
	TaskID  string
	Type    string // "work" or "review"
	PTY     *consolePTYSession
	Started time.Time
}

// taskSessionResponse is the JSON representation of a task session.
type taskSessionResponse struct {
	TaskID  string `json:"task_id"`
	Type    string `json:"type"`
	Status  string `json:"status"` // "running" or "exited"
	Started string `json:"started"`
}

// taskSessionManager manages dynamic PTY sessions per task.
type taskSessionManager struct {
	mu       sync.RWMutex
	sessions map[string]*taskSession
}

func newTaskSessionManager() *taskSessionManager {
	return &taskSessionManager{
		sessions: make(map[string]*taskSession),
	}
}

// sessionKey returns a unique key for a task session.
func sessionKey(taskID, sessionType string) string {
	if sessionType == "review" {
		return taskID + "-review"
	}
	return taskID
}

// startSession spawns an interactive claude PTY and sends the task prompt.
func (sm *taskSessionManager) startSession(taskID, sessionType, projectDir, prompt string) (*taskSession, error) {
	key := sessionKey(taskID, sessionType)

	sm.mu.Lock()
	if _, exists := sm.sessions[key]; exists {
		sm.mu.Unlock()
		return nil, fmt.Errorf("sesija %s već postoji", key)
	}
	sm.mu.Unlock()

	ptySess, err := spawnTaskPTY(projectDir)
	if err != nil {
		return nil, err
	}

	sess := &taskSession{
		TaskID:  taskID,
		Type:    sessionType,
		PTY:     ptySess,
		Started: time.Now(),
	}

	sm.mu.Lock()
	sm.sessions[key] = sess
	sm.mu.Unlock()

	log.Printf("Session[%s]: started (PID %d)", key, ptySess.Cmd.Process.Pid)

	// Send the task prompt after claude initializes
	go func() {
		subID := fmt.Sprintf("init-%d", time.Now().UnixNano())
		ch := ptySess.Subscribe(subID)

		timer := time.NewTimer(30 * time.Second)
		select {
		case <-ch:
			// Claude is alive and producing output
		case <-timer.C:
			log.Printf("Session[%s]: timeout waiting for claude to start", key)
		case <-ptySess.Done():
			log.Printf("Session[%s]: claude exited before producing output", key)
			ptySess.Unsubscribe(subID)
			return
		}
		timer.Stop()
		ptySess.Unsubscribe(subID)

		// Let claude fully render its welcome screen
		time.Sleep(2 * time.Second)

		// Type the prompt
		log.Printf("Session[%s]: sending prompt (%d bytes)", key, len(prompt))
		ptySess.WriteInput([]byte(prompt + "\n"))
	}()

	return sess, nil
}

// getSessionByKey returns a session by its full key.
func (sm *taskSessionManager) getSessionByKey(key string) *taskSession {
	sm.mu.RLock()
	defer sm.mu.RUnlock()
	return sm.sessions[key]
}

// listSessions returns all active sessions.
func (sm *taskSessionManager) listSessions() []taskSessionResponse {
	sm.mu.RLock()
	defer sm.mu.RUnlock()

	result := make([]taskSessionResponse, 0, len(sm.sessions))
	for _, sess := range sm.sessions {
		status := "running"
		select {
		case <-sess.PTY.Done():
			status = "exited"
		default:
		}

		result = append(result, taskSessionResponse{
			TaskID:  sess.TaskID,
			Type:    sess.Type,
			Status:  status,
			Started: sess.Started.Format("15:04:05"),
		})
	}
	return result
}

// killSession terminates a session and removes it.
func (sm *taskSessionManager) killSession(taskID, sessionType string) bool {
	key := sessionKey(taskID, sessionType)

	sm.mu.Lock()
	sess, exists := sm.sessions[key]
	if exists {
		delete(sm.sessions, key)
	}
	sm.mu.Unlock()

	if !exists {
		return false
	}

	log.Printf("Session[%s]: killed", key)
	sess.PTY.Close()
	return true
}

// handleConsolePage serves the console HTML page.
func (s *Server) handleConsolePage(c *gin.Context) {
	c.Header("Content-Type", "text/html; charset=utf-8")
	c.String(http.StatusOK, renderConsolePage())
}

// handleConsoleSessions returns all active task sessions as JSON.
func (s *Server) handleConsoleSessions(c *gin.Context) {
	sessions := s.console.listSessions()
	c.JSON(http.StatusOK, sessions)
}

// handleConsoleKill kills a task session.
func (s *Server) handleConsoleKill(c *gin.Context) {
	taskID := c.Param("taskID")
	sessionType := c.DefaultQuery("type", "work")

	if s.console.killSession(taskID, sessionType) {
		c.JSON(http.StatusOK, gin.H{"status": "killed", "task": taskID})
	} else {
		c.JSON(http.StatusNotFound, gin.H{"error": "sesija nije pronađena"})
	}
}

// buildWorkPrompt builds the prompt for a work session.
func buildWorkPrompt(taskID string, taskContent []byte) string {
	return fmt.Sprintf(`Radiš na tasku %s. Evo sadržaj taska:

%s

PRAVILA:
1. Pročitaj agents/coder/CLAUDE.md za pravila kodiranja
2. Kod piši u code/ folderu
3. Svi testovi moraju proći: go test ./... -count=1
4. Build mora proći: go build ./...
5. go vet ./... mora proći
6. Commituj sa porukom: %s: Opis na srpskom
7. Napiši izveštaj u TASKS/reports/%s-report.md
8. Premesti task fajl: mv TASKS/active/%s.md TASKS/review/%s.md
9. Kada sve završiš, reci "GOTOVO"`, taskID, string(taskContent), taskID, taskID, taskID, taskID)
}

// buildReviewPrompt builds the prompt for a review session.
func buildReviewPrompt(taskID string, taskContent, reportContent []byte) string {
	prompt := fmt.Sprintf(`Pregledaj task %s. Evo sadržaj taska:

%s
`, taskID, string(taskContent))

	if len(reportContent) > 0 {
		prompt += fmt.Sprintf(`
Izveštaj agenta:

%s
`, string(reportContent))
	}

	prompt += fmt.Sprintf(`
KORACI PREGLEDA:
1. Pročitaj agents/checker/CLAUDE.md za pravila
2. Proveri da li je kod napisan prema zadatku
3. Pokreni testove: go test ./... -count=1
4. Pokreni build: go build ./...
5. Pokreni vet: go vet ./...
6. Ako je SVE u redu:
   - Premesti task: mv TASKS/review/%s.md TASKS/done/%s.md
   - Reci "ODOBRENO"
7. Ako NIJE u redu:
   - Zapiši šta treba popraviti u task fajl
   - Premesti task: mv TASKS/review/%s.md TASKS/active/%s.md
   - Reci "VRAĆENO NA DORADU"`, taskID, taskID, taskID, taskID)

	return prompt
}

// handleReviewTask launches a review claude session for a task.
func (s *Server) handleReviewTask(c *gin.Context) {
	id := c.Param("id")

	// Read task content
	taskPath := filepath.Join(s.Config.TasksDir, "review", id+".md")
	taskContent, err := os.ReadFile(taskPath)
	if err != nil {
		c.JSON(http.StatusNotFound, gin.H{"error": "task nije pronađen u review/"})
		return
	}

	// Read report if exists
	reportPath := filepath.Join(s.Config.TasksDir, "reports", id+"-report.md")
	reportContent, _ := os.ReadFile(reportPath)

	// Build review prompt
	prompt := buildReviewPrompt(id, taskContent, reportContent)

	// Start review session
	_, err = s.console.startSession(id, "review", s.projectRoot(), prompt)
	if err != nil {
		c.JSON(http.StatusConflict, gin.H{"error": err.Error()})
		return
	}

	c.JSON(http.StatusOK, gin.H{"status": "started", "task": id, "type": "review"})
}

// timeNow returns the current time formatted as HH:MM:SS.
func timeNow() string {
	return time.Now().Format("15:04:05")
}