package db

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"strings"
	"sync"

	"gorm.io/driver/sqlite"
	"gorm.io/gorm"
	"rhemawavetech.com/rhemawave/internal/logger"
)

var DB *gorm.DB

// configCache is an in-memory cache of config values to avoid repeated DB queries.
var configCache = struct {
	sync.RWMutex
	m map[string]string
}{m: make(map[string]string)}

type Config struct {
	gorm.Model
	Key   string `gorm:"uniqueIndex"`
	Value string
}

type Proclamations struct {
	gorm.Model
	Title      string
	Content    string
	Commercial bool
	Selected   bool
	Favorite   bool
	Available  bool
}

type Log struct {
	gorm.Model
	Timestamp string
	Level     string
	Message   string
}

func (Log) TableName() string {
	return "log_entries"
}

type TOSSection struct {
	gorm.Model
	SectionNumber int `gorm:"uniqueIndex"`
	Title         string
	Content       string // raw HTML
}

var defaultConfigValues = map[string]string{
	"home_dir":                "",
	"assets_dir":              "", // Set dynamically in seedDefaults() to $HOME/.local/share/rhemawave
	"log_dir":                 "", // Set dynamically in seedDefaults() to $HOME/.local/share/rhemawave/logs.log
	"email_address":           "",
	"license_key":             "",
	"system_type":             "home",
	"system_capabilities":     "",
	"selected_audio":          "audio/audio.wav",
	"audio_device_name":       "",
	"application_font":        "Roboto-Regular",
	"init_font_size":          "128",
	"standard_font_size":      "32",
	"line_pattern":            "fibonacci",
	"last_volume":             "128",
	"audio_enabled":           "true",
	"tos_section_1_accepted":  "false",
	"tos_section_2_accepted":  "false",
	"tos_section_3_accepted":  "false",
	"tos_section_4_accepted":  "false",
	"tos_section_5_accepted":  "false",
	"tos_section_6_accepted":  "false",
	"tos_section_7_accepted":  "false",
	"tos_section_8_accepted":  "false",
	"tos_section_9_accepted":  "false",
	"tos_section_10_accepted": "false",
}

// InitDatabase initializes the SQLite database connection
// and performs auto-migration for all models
func InitDatabase(dbpath string) error {
	// Create the directory for the database if it doesn't exist
	dbDir := filepath.Dir(dbpath)
	if err := os.MkdirAll(dbDir, 0700); err != nil {
		log.Printf("Error creating database directory %s: %v", dbDir, err)
		return err
	}

	// Check if database file exists
	_, err := os.Stat(dbpath)
	dbExists := !os.IsNotExist(err)

	if !dbExists {
		log.Printf("Database file does not exist at %s, creating new database", dbpath)
	}

	dsn := fmt.Sprintf("file:%s", dbpath)

	DB, err = gorm.Open(sqlite.Open(dsn), &gorm.Config{})
	if err != nil {
		log.Printf("Error opening database: %v", err)
		return err
	}

	// Get underlying sql.DB to set pragmas
	sqlDB, err := DB.DB()
	if err != nil {
		logger.Error("Error getting underlying database connection: %v", err)
		return err
	}

	// Configure SQLite for reliability and performance
	pragmas := []string{
		"PRAGMA journal_mode=WAL",  // Write-Ahead Logging for better concurrency
		"PRAGMA synchronous=FULL",  // Maximum durability
		"PRAGMA foreign_keys=ON",   // Enable foreign key constraints
		"PRAGMA busy_timeout=5000", // Wait up to 5 seconds for locks
		"PRAGMA temp_store=MEMORY", // Keep temp tables in memory
	}

	for _, pragma := range pragmas {
		if _, err := sqlDB.Exec(pragma); err != nil {
			logger.Error("Error setting pragma %s: %v", pragma, err)
			return fmt.Errorf("failed to set pragma: %w", err)
		}
	}

	if err := sqlDB.Ping(); err != nil {
		logger.Error("Error pinging database: %v", err)
		return fmt.Errorf("database connection failed: %w", err)
	}

	log.Println("Database connected successfully")

	// Auto-migrate models
	err = DB.AutoMigrate(&Config{}, &Proclamations{}, &Log{}, &TOSSection{})
	if err != nil {
		logger.Error("Error migrating database: %v", err)
		return err
	}
	log.Println("Database migrated successfully")

	// Seed defaults
	err = ensureDefaultsExist()
	if err != nil {
		logger.Error("Error seeding default configuration values: %v", err)
		return err
	}
	err = seedDefaultProclamations()
	if err != nil {
		logger.Error("Error seeding default proclamations: %v", err)
		return err
	}

	err = seedDefaultTOSSections()
	if err != nil {
		logger.Error("Error seeding default TOS sections: %v", err)
		return err
	}

	log.Println("Database initialized successfully")
	return nil
}

// seedDefaultProclamations reads proclamation text files from the assets directory
// and populates the database on first run
func seedDefaultProclamations() error {
	var count int64
	err := DB.Model(&Proclamations{}).Count(&count).Error
	if err != nil {
		logger.Error("Error counting proclamations: %v", err)
		return err
	}

	// Only seed if table is empty
	if count > 0 {
		return nil
	}

	// Get the assets directory from config
	assetsDir, err := GetConfigValue("assets_dir")
	if err != nil {
		logger.Error("Error getting assets_dir: %v", err)
		return err
	}

	proclamationsBaseDir := assetsDir + "/proclamations"

	// Process both home and commercial directories
	subdirs := []string{"home", "commercial"}
	totalSeeded := 0

	for _, subdir := range subdirs {
		proclamationsDir := proclamationsBaseDir + "/" + subdir
		isCommercial := (subdir == "commercial")

		// Read all .txt files from the subdirectory
		files, err := os.ReadDir(proclamationsDir)
		if err != nil {
			logger.Error("Error reading proclamations directory %s: %v", proclamationsDir, err)
			continue // Continue with other directories even if one fails
		}

		for _, file := range files {
			if file.IsDir() || !strings.HasSuffix(file.Name(), ".txt") {
				continue
			}

			filePath := proclamationsDir + "/" + file.Name()
			content, err := os.ReadFile(filePath)
			if err != nil {
				logger.Error("Error reading file %s: %v", filePath, err)
				continue
			}

			// Extract title from filename (remove .txt extension)
			title := strings.TrimSuffix(file.Name(), ".txt")

			// Select "Relaxation" as the default proclamation
			isSelected := (title == "Relaxation")

			proclamation := Proclamations{
				Title:      title,
				Content:    string(content),
				Commercial: isCommercial,
				Selected:   isSelected,
				Favorite:   false,
				Available:  true,
			}

			if err := DB.Create(&proclamation).Error; err != nil {
				logger.Error("Error creating proclamation from %s: %v", file.Name(), err)
				return err
			}

			if isSelected {
				logger.Error("Set default proclamation: %s", title)
			}

			totalSeeded++
		}
	}

	logger.Error("Seeded %d default proclamations from %s", totalSeeded, proclamationsBaseDir)
	return nil
}

// GetConfigValue retrieves a configuration value by key.
// Results are cached in memory to avoid repeated DB queries.
func GetConfigValue(key string) (string, error) {
	configCache.RLock()
	if v, ok := configCache.m[key]; ok {
		configCache.RUnlock()
		return v, nil
	}
	configCache.RUnlock()

	var config Config
	result := DB.First(&config, "key = ?", key)
	if result.Error != nil {
		return "", result.Error
	}

	configCache.Lock()
	configCache.m[key] = config.Value
	configCache.Unlock()

	return config.Value, nil
}

// GetConfigValues retrieves all configuration key-value pairs
// Returns a map of key-value pairs OR any error encountered
// This is mainly for compatibility with legacy code, but can
// be useful for bulkl config referrals
func GetConfigValues() (map[string]string, error) {
	var configs []Config
	result := DB.Find(&configs)
	if result.Error != nil {
		return nil, result.Error
	}
	configMap := make(map[string]string)
	for _, config := range configs {
		configMap[config.Key] = config.Value
	}
	return configMap, nil
}

// SetConfigValue sets a configuration value by key
// Returns any error encountered || nil
func SetConfigValue(key, value string) error {
	// First try to find existing config
	var config Config
	result := DB.Where("key = ?", key).First(&config)

	if result.Error != nil {
		if result.Error == gorm.ErrRecordNotFound {
			// Record doesn't exist, create new one
			config = Config{Key: key, Value: value}
			if err := DB.Create(&config).Error; err != nil {
				return fmt.Errorf("failed to create config value for key %s: %w", key, err)
			}
		} else {
			// Some other error occurred
			return fmt.Errorf("failed to query config for key %s: %w", key, result.Error)
		}
	} else {
		// Record exists, update it
		config.Value = value
		if err := DB.Save(&config).Error; err != nil {
			return fmt.Errorf("failed to update config value for key %s: %w", key, err)
		}
	}

	// Update cache
	configCache.Lock()
	configCache.m[key] = value
	configCache.Unlock()

	return nil
}

// GetProclamations retrieves all proclamation entries from the database
// Returns a slice of Proclamations OR any error encountered
func GetProclamations() ([]Proclamations, error) {
	var proclamations []Proclamations
	result := DB.Find(&proclamations)
	if result.Error != nil {
		return nil, result.Error
	}
	return proclamations, nil
}

// seedDefaultTOSSections reads HTML files from the assets directory and populates the
// TOS sections table on first run.
func seedDefaultTOSSections() error {
	var count int64
	if err := DB.Model(&TOSSection{}).Count(&count).Error; err != nil {
		return err
	}
	if count > 0 {
		return nil
	}

	assetsDir, err := GetConfigValue("assets_dir")
	if err != nil {
		return fmt.Errorf("getting assets_dir: %w", err)
	}

	tosDir := filepath.Join(assetsDir, "tos")
	files, err := os.ReadDir(tosDir)
	if err != nil {
		return fmt.Errorf("reading tos directory %s: %w", tosDir, err)
	}

	seeded := 0
	for _, file := range files {
		if file.IsDir() || !strings.HasSuffix(file.Name(), ".html") {
			continue
		}

		// Parse filename: "01 - WELCOME.html" -> number=1, title="WELCOME"
		name := strings.TrimSuffix(file.Name(), ".html")
		parts := strings.SplitN(name, " - ", 2)
		if len(parts) != 2 {
			logger.Error("Skipping TOS file with unexpected name format: %s", file.Name())
			continue
		}

		var sectionNum int
		if _, err := fmt.Sscanf(parts[0], "%d", &sectionNum); err != nil {
			logger.Error("Skipping TOS file, cannot parse section number: %s", file.Name())
			continue
		}
		title := strings.TrimSpace(parts[1])

		content, err := os.ReadFile(filepath.Join(tosDir, file.Name()))
		if err != nil {
			logger.Error("Error reading TOS file %s: %v", file.Name(), err)
			continue
		}

		section := TOSSection{
			SectionNumber: sectionNum,
			Title:         title,
			Content:       string(content),
		}
		if err := DB.Create(&section).Error; err != nil {
			return fmt.Errorf("creating TOS section from %s: %w", file.Name(), err)
		}
		seeded++
	}

	logger.Info("Seeded %d TOS sections from %s", seeded, tosDir)
	return nil
}

// GetTOSSections returns all TOS sections ordered by section number.
func GetTOSSections() ([]TOSSection, error) {
	var sections []TOSSection
	result := DB.Order("section_number asc").Find(&sections)
	if result.Error != nil {
		return nil, result.Error
	}
	return sections, nil
}

// GetLogs retrieves log entries from the database, ordered by creation time ascending.
// If limit > 0, at most that many entries are returned.
func GetLogs(limit int) ([]Log, error) {
	var logs []Log
	query := DB.Order("created_at DESC")
	if limit > 0 {
		query = query.Limit(limit)
	}
	return logs, query.Find(&logs).Error
}

// ensureDefaultsExist checks the current configs table rows and inserts any new rows
// from defaultConfigValues to the database if they don't exist.
// This is essentially an automatic migration for new config values.
func ensureDefaultsExist() error {
	for key, value := range defaultConfigValues {
		var config Config
		result := DB.Where("key = ?", key).First(&config)

		// Always re-resolve path-based config values from the current binary location
		switch key {
		case "assets_dir":
			value = resolveAssetsDir()
		case "log_dir":
			value = filepath.Join(resolveAssetsDir(), "logs.log")
		}

		if result.Error == gorm.ErrRecordNotFound {
			// Key doesn't exist, create it with default value
			if err := DB.Create(&Config{Key: key, Value: value}).Error; err != nil {
				return fmt.Errorf("failed to create default config for %s: %w", key, err)
			}
			log.Printf("Added missing config key: %s", key)
		} else if result.Error != nil {
			return result.Error
		} else if (key == "assets_dir" || key == "log_dir") && config.Value != value {
			// Update stale path-based values (e.g. after Nix store update)
			config.Value = value
			if err := DB.Save(&config).Error; err != nil {
				return fmt.Errorf("failed to update config for %s: %w", key, err)
			}
			log.Printf("Updated stale config key: %s", key)
		} else if key == "selected_audio" && config.Value == "audio/7.83.wav" {
			// Migrate renamed audio file
			config.Value = value
			if err := DB.Save(&config).Error; err != nil {
				return fmt.Errorf("failed to migrate config for %s: %w", key, err)
			}
			log.Printf("Migrated config key: %s", key)
		}
	}
	return nil
}

func AudioEnabled() bool {
	on, err := GetConfigValue("audio_enabled")
	if err != nil {
		return false
	}
	return on == "true"
}

// resolveAssetsDir returns the assets directory by resolving relative to the
// running binary. For a binary at .../bin/rhemawave, assets are at
// .../share/rhemawave. Falls back to /usr/local/share/rhemawave.
func resolveAssetsDir() string {
	exe, err := os.Executable()
	if err == nil {
		exe, err = filepath.EvalSymlinks(exe)
	}
	if err == nil {
		return filepath.Join(filepath.Dir(exe), "..", "share", "rhemawave")
	}
	return filepath.Join("/usr", "local", "share", "rhemawave")
}