package template

import (
	"context"
	"database/sql"
	"fmt"
	"time"
)

// BuyinConfig represents a reusable buy-in configuration for tournaments.
type BuyinConfig struct {
	ID                     int64       `json:"id"`
	Name                   string      `json:"name"`
	BuyinAmount            int64       `json:"buyin_amount"`
	StartingChips          int64       `json:"starting_chips"`
	RakeTotal              int64       `json:"rake_total"`
	BountyAmount           int64       `json:"bounty_amount"`
	BountyChip             int64       `json:"bounty_chip"`
	RebuyAllowed           bool        `json:"rebuy_allowed"`
	RebuyCost              int64       `json:"rebuy_cost"`
	RebuyChips             int64       `json:"rebuy_chips"`
	RebuyRake              int64       `json:"rebuy_rake"`
	RebuyLimit             int         `json:"rebuy_limit"`
	RebuyLevelCutoff       *int        `json:"rebuy_level_cutoff,omitempty"`
	RebuyTimeCutoffSeconds *int        `json:"rebuy_time_cutoff_seconds,omitempty"`
	RebuyChipThreshold     *int64      `json:"rebuy_chip_threshold,omitempty"`
	AddonAllowed           bool        `json:"addon_allowed"`
	AddonCost              int64       `json:"addon_cost"`
	AddonChips             int64       `json:"addon_chips"`
	AddonRake              int64       `json:"addon_rake"`
	AddonLevelStart        *int        `json:"addon_level_start,omitempty"`
	AddonLevelEnd          *int        `json:"addon_level_end,omitempty"`
	ReentryAllowed         bool        `json:"reentry_allowed"`
	ReentryLimit           int         `json:"reentry_limit"`
	LateRegLevelCutoff     *int        `json:"late_reg_level_cutoff,omitempty"`
	LateRegTimeCutoffSecs  *int        `json:"late_reg_time_cutoff_seconds,omitempty"`
	RakeSplits             []RakeSplit `json:"rake_splits,omitempty"`
	CreatedAt              time.Time   `json:"created_at"`
	UpdatedAt              time.Time   `json:"updated_at"`
}

// RakeSplit defines how rake is distributed across categories.
type RakeSplit struct {
	ID            int64  `json:"id,omitempty"`
	BuyinConfigID int64  `json:"buyin_config_id,omitempty"`
	Category      string `json:"category"`
	Amount        int64  `json:"amount"`
}

// BuyinService provides CRUD operations for buy-in configs.
type BuyinService struct {
	db *sql.DB
}

// NewBuyinService creates a new BuyinService.
func NewBuyinService(db *sql.DB) *BuyinService {
	return &BuyinService{db: db}
}

// validateBuyinConfig checks that the config is valid.
func validateBuyinConfig(cfg *BuyinConfig) error {
	if cfg.Name == "" {
		return fmt.Errorf("buy-in config name is required")
	}
	if cfg.BuyinAmount < 0 {
		return fmt.Errorf("buyin_amount must be non-negative")
	}
	if cfg.StartingChips < 0 {
		return fmt.Errorf("starting_chips must be non-negative")
	}
	if cfg.RakeTotal < 0 {
		return fmt.Errorf("rake_total must be non-negative")
	}
	if cfg.BountyAmount < 0 {
		return fmt.Errorf("bounty_amount must be non-negative")
	}
	if cfg.BountyAmount > 0 && cfg.BountyChip <= 0 {
		return fmt.Errorf("bounty_chip must be positive when bounty_amount > 0")
	}
	if cfg.RebuyCost < 0 || cfg.RebuyChips < 0 || cfg.RebuyRake < 0 {
		return fmt.Errorf("rebuy values must be non-negative")
	}
	if cfg.RebuyLimit < 0 {
		return fmt.Errorf("rebuy_limit must be non-negative")
	}
	if cfg.AddonCost < 0 || cfg.AddonChips < 0 || cfg.AddonRake < 0 {
		return fmt.Errorf("addon values must be non-negative")
	}
	if cfg.ReentryLimit < 0 {
		return fmt.Errorf("reentry_limit must be non-negative")
	}

	// Validate rake splits sum = rake_total
	if len(cfg.RakeSplits) > 0 {
		var splitSum int64
		for _, split := range cfg.RakeSplits {
			if split.Amount < 0 {
				return fmt.Errorf("rake split amount must be non-negative")
			}
			validCategories := map[string]bool{"house": true, "staff": true, "league": true, "season_reserve": true}
			if !validCategories[split.Category] {
				return fmt.Errorf("invalid rake split category: %q", split.Category)
			}
			splitSum += split.Amount
		}
		if splitSum != cfg.RakeTotal {
			return fmt.Errorf("rake splits sum (%d) does not match rake_total (%d)", splitSum, cfg.RakeTotal)
		}
	}

	return nil
}

// CreateBuyinConfig creates a new buy-in configuration.
func (s *BuyinService) CreateBuyinConfig(ctx context.Context, cfg *BuyinConfig) (*BuyinConfig, error) {
	if err := validateBuyinConfig(cfg); err != nil {
		return nil, err
	}

	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return nil, fmt.Errorf("begin transaction: %w", err)
	}
	defer tx.Rollback()

	now := time.Now().Unix()
	res, err := tx.ExecContext(ctx,
		`INSERT INTO buyin_configs (name, buyin_amount, starting_chips, rake_total, bounty_amount, bounty_chip,
		 rebuy_allowed, rebuy_cost, rebuy_chips, rebuy_rake, rebuy_limit, rebuy_level_cutoff, rebuy_time_cutoff_seconds, rebuy_chip_threshold,
		 addon_allowed, addon_cost, addon_chips, addon_rake, addon_level_start, addon_level_end,
		 reentry_allowed, reentry_limit, late_reg_level_cutoff, late_reg_time_cutoff_seconds,
		 created_at, updated_at)
		 VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)`,
		cfg.Name, cfg.BuyinAmount, cfg.StartingChips, cfg.RakeTotal, cfg.BountyAmount, cfg.BountyChip,
		boolToInt(cfg.RebuyAllowed), cfg.RebuyCost, cfg.RebuyChips, cfg.RebuyRake, cfg.RebuyLimit,
		cfg.RebuyLevelCutoff, cfg.RebuyTimeCutoffSeconds, cfg.RebuyChipThreshold,
		boolToInt(cfg.AddonAllowed), cfg.AddonCost, cfg.AddonChips, cfg.AddonRake,
		cfg.AddonLevelStart, cfg.AddonLevelEnd,
		boolToInt(cfg.ReentryAllowed), cfg.ReentryLimit,
		cfg.LateRegLevelCutoff, cfg.LateRegTimeCutoffSecs,
		now, now,
	)
	if err != nil {
		return nil, fmt.Errorf("insert buyin config: %w", err)
	}
	id, err := res.LastInsertId()
	if err != nil {
		return nil, fmt.Errorf("get buyin config id: %w", err)
	}

	if err := insertRakeSplits(ctx, tx, id, cfg.RakeSplits); err != nil {
		return nil, err
	}

	if err := tx.Commit(); err != nil {
		return nil, fmt.Errorf("commit: %w", err)
	}

	return s.GetBuyinConfig(ctx, id)
}

func insertRakeSplits(ctx context.Context, tx *sql.Tx, configID int64, splits []RakeSplit) error {
	for i, split := range splits {
		_, err := tx.ExecContext(ctx,
			"INSERT INTO rake_splits (buyin_config_id, category, amount) VALUES (?, ?, ?)",
			configID, split.Category, split.Amount,
		)
		if err != nil {
			return fmt.Errorf("insert rake split %d: %w", i, err)
		}
	}
	return nil
}

// GetBuyinConfig retrieves a buy-in config by ID, including rake splits.
func (s *BuyinService) GetBuyinConfig(ctx context.Context, id int64) (*BuyinConfig, error) {
	cfg := &BuyinConfig{}
	var createdAt, updatedAt int64
	var rebuyAllowed, addonAllowed, reentryAllowed int

	err := s.db.QueryRowContext(ctx,
		`SELECT id, name, buyin_amount, starting_chips, rake_total, bounty_amount, bounty_chip,
		 rebuy_allowed, rebuy_cost, rebuy_chips, rebuy_rake, rebuy_limit, rebuy_level_cutoff, rebuy_time_cutoff_seconds, rebuy_chip_threshold,
		 addon_allowed, addon_cost, addon_chips, addon_rake, addon_level_start, addon_level_end,
		 reentry_allowed, reentry_limit, late_reg_level_cutoff, late_reg_time_cutoff_seconds,
		 created_at, updated_at
		 FROM buyin_configs WHERE id = ?`, id,
	).Scan(
		&cfg.ID, &cfg.Name, &cfg.BuyinAmount, &cfg.StartingChips, &cfg.RakeTotal, &cfg.BountyAmount, &cfg.BountyChip,
		&rebuyAllowed, &cfg.RebuyCost, &cfg.RebuyChips, &cfg.RebuyRake, &cfg.RebuyLimit,
		&cfg.RebuyLevelCutoff, &cfg.RebuyTimeCutoffSeconds, &cfg.RebuyChipThreshold,
		&addonAllowed, &cfg.AddonCost, &cfg.AddonChips, &cfg.AddonRake,
		&cfg.AddonLevelStart, &cfg.AddonLevelEnd,
		&reentryAllowed, &cfg.ReentryLimit,
		&cfg.LateRegLevelCutoff, &cfg.LateRegTimeCutoffSecs,
		&createdAt, &updatedAt,
	)
	if err == sql.ErrNoRows {
		return nil, fmt.Errorf("buyin config not found: %d", id)
	}
	if err != nil {
		return nil, fmt.Errorf("get buyin config: %w", err)
	}
	cfg.RebuyAllowed = rebuyAllowed != 0
	cfg.AddonAllowed = addonAllowed != 0
	cfg.ReentryAllowed = reentryAllowed != 0
	cfg.CreatedAt = time.Unix(createdAt, 0)
	cfg.UpdatedAt = time.Unix(updatedAt, 0)

	// Load rake splits
	rows, err := s.db.QueryContext(ctx,
		"SELECT id, buyin_config_id, category, amount FROM rake_splits WHERE buyin_config_id = ? ORDER BY category", id,
	)
	if err != nil {
		return nil, fmt.Errorf("get rake splits: %w", err)
	}
	defer rows.Close()

	for rows.Next() {
		var split RakeSplit
		if err := rows.Scan(&split.ID, &split.BuyinConfigID, &split.Category, &split.Amount); err != nil {
			return nil, fmt.Errorf("scan rake split: %w", err)
		}
		cfg.RakeSplits = append(cfg.RakeSplits, split)
	}
	return cfg, rows.Err()
}

// ListBuyinConfigs returns all buy-in configs (without rake splits).
func (s *BuyinService) ListBuyinConfigs(ctx context.Context) ([]BuyinConfig, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT id, name, buyin_amount, starting_chips, rake_total, bounty_amount, bounty_chip,
		 rebuy_allowed, addon_allowed, reentry_allowed,
		 created_at, updated_at
		 FROM buyin_configs ORDER BY name`,
	)
	if err != nil {
		return nil, fmt.Errorf("list buyin configs: %w", err)
	}
	defer rows.Close()

	var configs []BuyinConfig
	for rows.Next() {
		var cfg BuyinConfig
		var createdAt, updatedAt int64
		var rebuyAllowed, addonAllowed, reentryAllowed int
		if err := rows.Scan(
			&cfg.ID, &cfg.Name, &cfg.BuyinAmount, &cfg.StartingChips, &cfg.RakeTotal, &cfg.BountyAmount, &cfg.BountyChip,
			&rebuyAllowed, &addonAllowed, &reentryAllowed,
			&createdAt, &updatedAt,
		); err != nil {
			return nil, fmt.Errorf("scan buyin config: %w", err)
		}
		cfg.RebuyAllowed = rebuyAllowed != 0
		cfg.AddonAllowed = addonAllowed != 0
		cfg.ReentryAllowed = reentryAllowed != 0
		cfg.CreatedAt = time.Unix(createdAt, 0)
		cfg.UpdatedAt = time.Unix(updatedAt, 0)
		configs = append(configs, cfg)
	}
	return configs, rows.Err()
}

// UpdateBuyinConfig updates a buy-in config and replaces its rake splits.
func (s *BuyinService) UpdateBuyinConfig(ctx context.Context, id int64, cfg *BuyinConfig) error {
	cfg.ID = id
	if err := validateBuyinConfig(cfg); err != nil {
		return err
	}

	tx, err := s.db.BeginTx(ctx, nil)
	if err != nil {
		return fmt.Errorf("begin transaction: %w", err)
	}
	defer tx.Rollback()

	now := time.Now().Unix()
	res, err := tx.ExecContext(ctx,
		`UPDATE buyin_configs SET name = ?, buyin_amount = ?, starting_chips = ?, rake_total = ?,
		 bounty_amount = ?, bounty_chip = ?,
		 rebuy_allowed = ?, rebuy_cost = ?, rebuy_chips = ?, rebuy_rake = ?, rebuy_limit = ?,
		 rebuy_level_cutoff = ?, rebuy_time_cutoff_seconds = ?, rebuy_chip_threshold = ?,
		 addon_allowed = ?, addon_cost = ?, addon_chips = ?, addon_rake = ?,
		 addon_level_start = ?, addon_level_end = ?,
		 reentry_allowed = ?, reentry_limit = ?,
		 late_reg_level_cutoff = ?, late_reg_time_cutoff_seconds = ?,
		 updated_at = ?
		 WHERE id = ?`,
		cfg.Name, cfg.BuyinAmount, cfg.StartingChips, cfg.RakeTotal,
		cfg.BountyAmount, cfg.BountyChip,
		boolToInt(cfg.RebuyAllowed), cfg.RebuyCost, cfg.RebuyChips, cfg.RebuyRake, cfg.RebuyLimit,
		cfg.RebuyLevelCutoff, cfg.RebuyTimeCutoffSeconds, cfg.RebuyChipThreshold,
		boolToInt(cfg.AddonAllowed), cfg.AddonCost, cfg.AddonChips, cfg.AddonRake,
		cfg.AddonLevelStart, cfg.AddonLevelEnd,
		boolToInt(cfg.ReentryAllowed), cfg.ReentryLimit,
		cfg.LateRegLevelCutoff, cfg.LateRegTimeCutoffSecs,
		now, id,
	)
	if err != nil {
		return fmt.Errorf("update buyin config: %w", err)
	}
	n, _ := res.RowsAffected()
	if n == 0 {
		return fmt.Errorf("buyin config not found: %d", id)
	}

	// Replace rake splits
	if _, err := tx.ExecContext(ctx, "DELETE FROM rake_splits WHERE buyin_config_id = ?", id); err != nil {
		return fmt.Errorf("delete old rake splits: %w", err)
	}
	if err := insertRakeSplits(ctx, tx, id, cfg.RakeSplits); err != nil {
		return err
	}

	return tx.Commit()
}

// DeleteBuyinConfig deletes a buy-in config.
func (s *BuyinService) DeleteBuyinConfig(ctx context.Context, id int64) error {
	// Check if referenced by active tournaments
	var refCount int
	err := s.db.QueryRowContext(ctx,
		"SELECT COUNT(*) FROM tournaments WHERE buyin_config_id = ? AND status NOT IN ('completed', 'cancelled')", id,
	).Scan(&refCount)
	if err != nil {
		return fmt.Errorf("check references: %w", err)
	}
	if refCount > 0 {
		return fmt.Errorf("buyin config is referenced by %d active tournament(s)", refCount)
	}

	res, err := s.db.ExecContext(ctx, "DELETE FROM buyin_configs WHERE id = ?", id)
	if err != nil {
		return fmt.Errorf("delete buyin config: %w", err)
	}
	n, _ := res.RowsAffected()
	if n == 0 {
		return fmt.Errorf("buyin config not found: %d", id)
	}
	return nil
}

// DuplicateBuyinConfig creates an independent copy of a buy-in config.
func (s *BuyinService) DuplicateBuyinConfig(ctx context.Context, id int64, newName string) (*BuyinConfig, error) {
	original, err := s.GetBuyinConfig(ctx, id)
	if err != nil {
		return nil, fmt.Errorf("get original: %w", err)
	}

	if newName == "" {
		newName = original.Name + " (Copy)"
	}

	copy := *original
	copy.ID = 0
	copy.Name = newName
	return s.CreateBuyinConfig(ctx, &copy)
}

// boolToInt converts a Go bool to SQLite integer.
func boolToInt(b bool) int {
	if b {
		return 1
	}
	return 0
}