package db

import (
	"context"
	"database/sql"
	"encoding/json"
	"strings"
	"time"

	"github.com/gooseek/backend/internal/computer"
)

type ComputerMemoryRepo struct {
	db *sql.DB
}

func NewComputerMemoryRepo(db *sql.DB) *ComputerMemoryRepo {
	return &ComputerMemoryRepo{db: db}
}

func (r *ComputerMemoryRepo) Migrate() error {
	query := `
	CREATE TABLE IF NOT EXISTS computer_memory (
		id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
		user_id UUID NOT NULL,
		task_id UUID,
		key VARCHAR(255) NOT NULL,
		value JSONB NOT NULL,
		type VARCHAR(50),
		tags TEXT[],
		created_at TIMESTAMPTZ DEFAULT NOW(),
		expires_at TIMESTAMPTZ
	);

	CREATE INDEX IF NOT EXISTS idx_computer_memory_user_id ON computer_memory(user_id);
	CREATE INDEX IF NOT EXISTS idx_computer_memory_task_id ON computer_memory(task_id);
	CREATE INDEX IF NOT EXISTS idx_computer_memory_type ON computer_memory(type);
	CREATE INDEX IF NOT EXISTS idx_computer_memory_expires ON computer_memory(expires_at) WHERE expires_at IS NOT NULL;
	CREATE INDEX IF NOT EXISTS idx_computer_memory_key ON computer_memory(key);
	`

	_, err := r.db.Exec(query)
	return err
}

func (r *ComputerMemoryRepo) Store(ctx context.Context, entry *computer.MemoryEntry) error {
	valueJSON, err := json.Marshal(entry.Value)
	if err != nil {
		return err
	}

	query := `
		INSERT INTO computer_memory (id, user_id, task_id, key, value, type, tags, created_at, expires_at)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
		ON CONFLICT (id) DO UPDATE SET
			value = EXCLUDED.value,
			type = EXCLUDED.type,
			tags = EXCLUDED.tags,
			expires_at = EXCLUDED.expires_at
	`

	var taskID interface{}
	if entry.TaskID != "" {
		taskID = entry.TaskID
	}

	_, err = r.db.ExecContext(ctx, query,
		entry.ID,
		entry.UserID,
		taskID,
		entry.Key,
		valueJSON,
		entry.Type,
		entry.Tags,
		entry.CreatedAt,
		entry.ExpiresAt,
	)

	return err
}

func (r *ComputerMemoryRepo) GetByUser(ctx context.Context, userID string, limit int) ([]computer.MemoryEntry, error) {
	query := `
		SELECT id, user_id, task_id, key, value, type, tags, created_at, expires_at
		FROM computer_memory
		WHERE user_id = $1
		AND (expires_at IS NULL OR expires_at > NOW())
		ORDER BY created_at DESC
		LIMIT $2
	`

	rows, err := r.db.QueryContext(ctx, query, userID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	return r.scanEntries(rows)
}

func (r *ComputerMemoryRepo) GetByTask(ctx context.Context, taskID string) ([]computer.MemoryEntry, error) {
	query := `
		SELECT id, user_id, task_id, key, value, type, tags, created_at, expires_at
		FROM computer_memory
		WHERE task_id = $1
		AND (expires_at IS NULL OR expires_at > NOW())
		ORDER BY created_at ASC
	`

	rows, err := r.db.QueryContext(ctx, query, taskID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	return r.scanEntries(rows)
}

func (r *ComputerMemoryRepo) Search(ctx context.Context, userID, query string, limit int) ([]computer.MemoryEntry, error) {
	searchTerms := strings.Fields(strings.ToLower(query))
	if len(searchTerms) == 0 {
		return r.GetByUser(ctx, userID, limit)
	}

	likePatterns := make([]string, len(searchTerms))
	args := make([]interface{}, len(searchTerms)+2)
	args[0] = userID

	for i, term := range searchTerms {
		likePatterns[i] = "%" + term + "%"
		args[i+1] = likePatterns[i]
	}
	args[len(args)-1] = limit

	var conditions []string
	for i := range searchTerms {
		conditions = append(conditions, "(LOWER(key) LIKE $"+string(rune('2'+i))+" OR LOWER(value::text) LIKE $"+string(rune('2'+i))+")")
	}

	sqlQuery := `
		SELECT id, user_id, task_id, key, value, type, tags, created_at, expires_at
		FROM computer_memory
		WHERE user_id = $1
		AND (expires_at IS NULL OR expires_at > NOW())
		AND (` + strings.Join(conditions, " OR ") + `)
		ORDER BY created_at DESC
		LIMIT $` + string(rune('2'+len(searchTerms)))

	rows, err := r.db.QueryContext(ctx, sqlQuery, args...)
	if err != nil {
		return r.GetByUser(ctx, userID, limit)
	}
	defer rows.Close()

	return r.scanEntries(rows)
}

func (r *ComputerMemoryRepo) GetByType(ctx context.Context, userID, memType string, limit int) ([]computer.MemoryEntry, error) {
	query := `
		SELECT id, user_id, task_id, key, value, type, tags, created_at, expires_at
		FROM computer_memory
		WHERE user_id = $1 AND type = $2
		AND (expires_at IS NULL OR expires_at > NOW())
		ORDER BY created_at DESC
		LIMIT $3
	`

	rows, err := r.db.QueryContext(ctx, query, userID, memType, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	return r.scanEntries(rows)
}

func (r *ComputerMemoryRepo) GetByKey(ctx context.Context, userID, key string) (*computer.MemoryEntry, error) {
	query := `
		SELECT id, user_id, task_id, key, value, type, tags, created_at, expires_at
		FROM computer_memory
		WHERE user_id = $1 AND key = $2
		AND (expires_at IS NULL OR expires_at > NOW())
		ORDER BY created_at DESC
		LIMIT 1
	`

	var entry computer.MemoryEntry
	var valueJSON []byte
	var taskID sql.NullString
	var expiresAt sql.NullTime
	var tags []string

	err := r.db.QueryRowContext(ctx, query, userID, key).Scan(
		&entry.ID,
		&entry.UserID,
		&taskID,
		&entry.Key,
		&valueJSON,
		&entry.Type,
		&tags,
		&entry.CreatedAt,
		&expiresAt,
	)

	if err != nil {
		return nil, err
	}

	if taskID.Valid {
		entry.TaskID = taskID.String
	}
	if expiresAt.Valid {
		entry.ExpiresAt = &expiresAt.Time
	}
	entry.Tags = tags

	json.Unmarshal(valueJSON, &entry.Value)

	return &entry, nil
}

func (r *ComputerMemoryRepo) Delete(ctx context.Context, id string) error {
	query := `DELETE FROM computer_memory WHERE id = $1`
	_, err := r.db.ExecContext(ctx, query, id)
	return err
}

func (r *ComputerMemoryRepo) DeleteByUser(ctx context.Context, userID string) error {
	query := `DELETE FROM computer_memory WHERE user_id = $1`
	_, err := r.db.ExecContext(ctx, query, userID)
	return err
}

func (r *ComputerMemoryRepo) DeleteByTask(ctx context.Context, taskID string) error {
	query := `DELETE FROM computer_memory WHERE task_id = $1`
	_, err := r.db.ExecContext(ctx, query, taskID)
	return err
}

func (r *ComputerMemoryRepo) DeleteExpired(ctx context.Context) (int64, error) {
	query := `DELETE FROM computer_memory WHERE expires_at IS NOT NULL AND expires_at < NOW()`
	result, err := r.db.ExecContext(ctx, query)
	if err != nil {
		return 0, err
	}
	return result.RowsAffected()
}

func (r *ComputerMemoryRepo) scanEntries(rows *sql.Rows) ([]computer.MemoryEntry, error) {
	var entries []computer.MemoryEntry

	for rows.Next() {
		var entry computer.MemoryEntry
		var valueJSON []byte
		var taskID sql.NullString
		var expiresAt sql.NullTime
		var tags []string

		err := rows.Scan(
			&entry.ID,
			&entry.UserID,
			&taskID,
			&entry.Key,
			&valueJSON,
			&entry.Type,
			&tags,
			&entry.CreatedAt,
			&expiresAt,
		)
		if err != nil {
			continue
		}

		if taskID.Valid {
			entry.TaskID = taskID.String
		}
		if expiresAt.Valid {
			entry.ExpiresAt = &expiresAt.Time
		}
		entry.Tags = tags

		json.Unmarshal(valueJSON, &entry.Value)

		entries = append(entries, entry)
	}

	return entries, nil
}

func (r *ComputerMemoryRepo) Count(ctx context.Context, userID string) (int64, error) {
	query := `
		SELECT COUNT(*)
		FROM computer_memory
		WHERE user_id = $1
		AND (expires_at IS NULL OR expires_at > NOW())
	`
	var count int64
	err := r.db.QueryRowContext(ctx, query, userID).Scan(&count)
	return count, err
}

func (r *ComputerMemoryRepo) UpdateExpiry(ctx context.Context, id string, expiresAt time.Time) error {
	query := `UPDATE computer_memory SET expires_at = $1 WHERE id = $2`
	_, err := r.db.ExecContext(ctx, query, expiresAt, id)
	return err
}