package handlers

import (
	"encoding/json"
	"net/http"
	"os"
	"path/filepath"
	"sync"
	"time"

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

// SeedURL represents a seed URL configuration
type SeedURL struct {
	ID            string    `json:"id"`
	URL           string    `json:"url"`
	Category      string    `json:"category"`
	Name          string    `json:"name"`
	Description   string    `json:"description"`
	TrustBoost    float64   `json:"trustBoost"`
	Enabled       bool      `json:"enabled"`
	LastCrawled   *string   `json:"lastCrawled,omitempty"`
	DocumentCount int       `json:"documentCount,omitempty"`
	CreatedAt     time.Time `json:"createdAt"`
	UpdatedAt     time.Time `json:"updatedAt"`
}

// CrawlStats contains crawl statistics
type CrawlStats struct {
	TotalDocuments        int                `json:"totalDocuments"`
	TotalSeeds            int                `json:"totalSeeds"`
	LastCrawlTime         *string            `json:"lastCrawlTime,omitempty"`
	CrawlStatus           string             `json:"crawlStatus"`
	DocumentsPerCategory  map[string]int     `json:"documentsPerCategory"`
	DocumentsPerDocType   map[string]int     `json:"documentsPerDocType"`
	AvgTrustScore         float64            `json:"avgTrustScore"`
}

// SeedStore manages seed URLs in memory and file
type SeedStore struct {
	seeds    map[string]SeedURL
	mu       sync.RWMutex
	filePath string
}

var seedStore *SeedStore
var crawlStatus = "idle"
var lastCrawlTime *string

// InitSeedStore initializes the seed store
func InitSeedStore(seedsDir string) error {
	seedStore = &SeedStore{
		seeds:    make(map[string]SeedURL),
		filePath: filepath.Join(seedsDir, "seeds.json"),
	}

	// Try to load existing seeds from JSON file
	if err := seedStore.loadFromFile(); err != nil {
		// If file doesn't exist, load from txt files
		return seedStore.loadFromTxtFiles(seedsDir)
	}
	return nil
}

func (s *SeedStore) loadFromFile() error {
	data, err := os.ReadFile(s.filePath)
	if err != nil {
		return err
	}

	var seeds []SeedURL
	if err := json.Unmarshal(data, &seeds); err != nil {
		return err
	}

	s.mu.Lock()
	defer s.mu.Unlock()

	for _, seed := range seeds {
		s.seeds[seed.ID] = seed
	}
	return nil
}

func (s *SeedStore) loadFromTxtFiles(seedsDir string) error {
	// Default seeds from category files
	defaultSeeds := []SeedURL{
		{ID: uuid.New().String(), URL: "https://www.kmk.org", Category: "federal", Name: "Kultusministerkonferenz", Description: "Beschlüsse und Bildungsstandards", TrustBoost: 0.50, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.bildungsserver.de", Category: "federal", Name: "Deutscher Bildungsserver", Description: "Zentrale Bildungsinformationen", TrustBoost: 0.50, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.bpb.de", Category: "federal", Name: "Bundeszentrale politische Bildung", Description: "Politische Bildung", TrustBoost: 0.45, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.bmbf.de", Category: "federal", Name: "BMBF", Description: "Bundesbildungsministerium", TrustBoost: 0.50, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.iqb.hu-berlin.de", Category: "federal", Name: "IQB", Description: "Institut Qualitätsentwicklung", TrustBoost: 0.50, Enabled: true},

		// Science
		{ID: uuid.New().String(), URL: "https://www.bertelsmann-stiftung.de/de/themen/bildung", Category: "science", Name: "Bertelsmann Stiftung", Description: "Bildungsstudien und Ländermonitor", TrustBoost: 0.40, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.oecd.org/pisa", Category: "science", Name: "PISA-Studien", Description: "Internationale Schulleistungsstudie", TrustBoost: 0.45, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.iea.nl/studies/iea/pirls", Category: "science", Name: "IGLU/PIRLS", Description: "Internationale Grundschul-Lese-Untersuchung", TrustBoost: 0.45, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.iea.nl/studies/iea/timss", Category: "science", Name: "TIMSS", Description: "Trends in International Mathematics and Science Study", TrustBoost: 0.45, Enabled: true},

		// Bundesländer
		{ID: uuid.New().String(), URL: "https://www.km.bayern.de", Category: "states", Name: "Bayern Kultusministerium", Description: "Lehrpläne Bayern", TrustBoost: 0.45, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.schulministerium.nrw", Category: "states", Name: "NRW Schulministerium", Description: "Lehrpläne NRW", TrustBoost: 0.45, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.berlin.de/sen/bildung", Category: "states", Name: "Berlin Bildung", Description: "Rahmenlehrpläne Berlin", TrustBoost: 0.45, Enabled: true},
		{ID: uuid.New().String(), URL: "https://kultusministerium.hessen.de", Category: "states", Name: "Hessen Kultusministerium", Description: "Kerncurricula Hessen", TrustBoost: 0.45, Enabled: true},

		// Portale
		{ID: uuid.New().String(), URL: "https://www.lehrer-online.de", Category: "portals", Name: "Lehrer-Online", Description: "Unterrichtsmaterialien", TrustBoost: 0.20, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.4teachers.de", Category: "portals", Name: "4teachers", Description: "Lehrercommunity", TrustBoost: 0.20, Enabled: true},
		{ID: uuid.New().String(), URL: "https://www.zum.de", Category: "portals", Name: "ZUM", Description: "Zentrale für Unterrichtsmedien", TrustBoost: 0.25, Enabled: true},
	}

	s.mu.Lock()
	defer s.mu.Unlock()

	now := time.Now()
	for _, seed := range defaultSeeds {
		seed.CreatedAt = now
		seed.UpdatedAt = now
		s.seeds[seed.ID] = seed
	}

	return s.saveToFile()
}

func (s *SeedStore) saveToFile() error {
	seeds := make([]SeedURL, 0, len(s.seeds))
	for _, seed := range s.seeds {
		seeds = append(seeds, seed)
	}

	data, err := json.MarshalIndent(seeds, "", "  ")
	if err != nil {
		return err
	}

	return os.WriteFile(s.filePath, data, 0644)
}

// GetAllSeeds returns all seeds
func (s *SeedStore) GetAllSeeds() []SeedURL {
	s.mu.RLock()
	defer s.mu.RUnlock()

	seeds := make([]SeedURL, 0, len(s.seeds))
	for _, seed := range s.seeds {
		seeds = append(seeds, seed)
	}
	return seeds
}

// GetSeed returns a single seed by ID
func (s *SeedStore) GetSeed(id string) (SeedURL, bool) {
	s.mu.RLock()
	defer s.mu.RUnlock()
	seed, ok := s.seeds[id]
	return seed, ok
}

// CreateSeed adds a new seed
func (s *SeedStore) CreateSeed(seed SeedURL) (SeedURL, error) {
	s.mu.Lock()
	defer s.mu.Unlock()

	seed.ID = uuid.New().String()
	seed.CreatedAt = time.Now()
	seed.UpdatedAt = time.Now()
	s.seeds[seed.ID] = seed

	if err := s.saveToFile(); err != nil {
		delete(s.seeds, seed.ID)
		return SeedURL{}, err
	}

	return seed, nil
}

// UpdateSeed updates an existing seed
func (s *SeedStore) UpdateSeed(id string, updates SeedURL) (SeedURL, bool, error) {
	s.mu.Lock()
	defer s.mu.Unlock()

	seed, ok := s.seeds[id]
	if !ok {
		return SeedURL{}, false, nil
	}

	// Update fields
	if updates.URL != "" {
		seed.URL = updates.URL
	}
	if updates.Name != "" {
		seed.Name = updates.Name
	}
	if updates.Category != "" {
		seed.Category = updates.Category
	}
	if updates.Description != "" {
		seed.Description = updates.Description
	}
	seed.TrustBoost = updates.TrustBoost
	seed.Enabled = updates.Enabled
	seed.UpdatedAt = time.Now()

	s.seeds[id] = seed

	if err := s.saveToFile(); err != nil {
		return SeedURL{}, true, err
	}

	return seed, true, nil
}

// DeleteSeed removes a seed
func (s *SeedStore) DeleteSeed(id string) bool {
	s.mu.Lock()
	defer s.mu.Unlock()

	if _, ok := s.seeds[id]; !ok {
		return false
	}

	delete(s.seeds, id)
	s.saveToFile()
	return true
}

// Admin Handlers

// GetSeeds returns all seed URLs
func (h *Handler) GetSeeds(c *gin.Context) {
	if seedStore == nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Seed store not initialized"})
		return
	}

	seeds := seedStore.GetAllSeeds()
	c.JSON(http.StatusOK, seeds)
}

// CreateSeed adds a new seed URL
func (h *Handler) CreateSeed(c *gin.Context) {
	if seedStore == nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Seed store not initialized"})
		return
	}

	var seed SeedURL
	if err := c.ShouldBindJSON(&seed); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request body", "details": err.Error()})
		return
	}

	if seed.URL == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "URL is required"})
		return
	}

	created, err := seedStore.CreateSeed(seed)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to create seed", "details": err.Error()})
		return
	}

	c.JSON(http.StatusCreated, created)
}

// UpdateSeed updates an existing seed URL
func (h *Handler) UpdateSeed(c *gin.Context) {
	if seedStore == nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Seed store not initialized"})
		return
	}

	id := c.Param("id")
	if id == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Seed ID required"})
		return
	}

	var updates SeedURL
	if err := c.ShouldBindJSON(&updates); err != nil {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Invalid request body", "details": err.Error()})
		return
	}

	updated, found, err := seedStore.UpdateSeed(id, updates)
	if err != nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Failed to update seed", "details": err.Error()})
		return
	}
	if !found {
		c.JSON(http.StatusNotFound, gin.H{"error": "Seed not found"})
		return
	}

	c.JSON(http.StatusOK, updated)
}

// DeleteSeed removes a seed URL
func (h *Handler) DeleteSeed(c *gin.Context) {
	if seedStore == nil {
		c.JSON(http.StatusInternalServerError, gin.H{"error": "Seed store not initialized"})
		return
	}

	id := c.Param("id")
	if id == "" {
		c.JSON(http.StatusBadRequest, gin.H{"error": "Seed ID required"})
		return
	}

	if !seedStore.DeleteSeed(id) {
		c.JSON(http.StatusNotFound, gin.H{"error": "Seed not found"})
		return
	}

	c.JSON(http.StatusOK, gin.H{"deleted": true, "id": id})
}

// GetStats returns crawl statistics
func (h *Handler) GetStats(c *gin.Context) {
	// Get document count from OpenSearch
	totalDocs := 0
	// TODO: Get real count from OpenSearch

	seeds := []SeedURL{}
	if seedStore != nil {
		seeds = seedStore.GetAllSeeds()
	}

	enabledSeeds := 0
	for _, seed := range seeds {
		if seed.Enabled {
			enabledSeeds++
		}
	}

	stats := CrawlStats{
		TotalDocuments: totalDocs,
		TotalSeeds:     enabledSeeds,
		LastCrawlTime:  lastCrawlTime,
		CrawlStatus:    crawlStatus,
		DocumentsPerCategory: map[string]int{
			"federal":      0,
			"states":       0,
			"science":      0,
			"universities": 0,
			"portals":      0,
		},
		DocumentsPerDocType: map[string]int{
			"Lehrplan":          0,
			"Arbeitsblatt":      0,
			"Unterrichtsentwurf": 0,
			"Erlass_Verordnung": 0,
			"Pruefung_Abitur":   0,
			"Studie_Bericht":    0,
			"Sonstiges":         0,
		},
		AvgTrustScore: 0.0,
	}

	c.JSON(http.StatusOK, stats)
}

// StartCrawl initiates a crawl run
func (h *Handler) StartCrawl(c *gin.Context) {
	if crawlStatus == "running" {
		c.JSON(http.StatusConflict, gin.H{"error": "Crawl already running"})
		return
	}

	crawlStatus = "running"

	// TODO: Start actual crawl in background goroutine
	go func() {
		time.Sleep(5 * time.Second) // Simulate crawl
		now := time.Now().Format(time.RFC3339)
		lastCrawlTime = &now
		crawlStatus = "idle"
	}()

	c.JSON(http.StatusAccepted, gin.H{
		"status":  "started",
		"message": "Crawl initiated",
	})
}

// SetupAdminRoutes configures admin API routes
func SetupAdminRoutes(r *gin.RouterGroup, h *Handler) {
	admin := r.Group("/admin")
	{
		// Seeds CRUD
		admin.GET("/seeds", h.GetSeeds)
		admin.POST("/seeds", h.CreateSeed)
		admin.PUT("/seeds/:id", h.UpdateSeed)
		admin.DELETE("/seeds/:id", h.DeleteSeed)

		// Stats
		admin.GET("/stats", h.GetStats)

		// Crawl control
		admin.POST("/crawl/start", h.StartCrawl)
	}
}