package store

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

	"coda/internal/models"

	"github.com/google/uuid"
)

type ListJobsParams struct {
	Status *models.JobStatus
	Limit  int
	Offset int
}

type JobRepository struct {
	db *sql.DB
}

func (r *JobRepository) Create(ctx context.Context, job *models.Job) error {
	if job.ID == "" {
		job.ID = uuid.New().String()
	}
	if job.CreatedAt.IsZero() {
		job.CreatedAt = time.Now().UTC()
	}

	_, err := r.db.ExecContext(ctx,
		`INSERT INTO jobs (id, artist, album, path, status, source, created_at)
		 VALUES (?, ?, ?, ?, ?, ?, ?)`,
		job.ID, job.Artist, job.Album, job.Path, job.Status, job.Source, job.CreatedAt,
	)
	if err != nil {
		return fmt.Errorf("insert job: %w", err)
	}
	return nil
}

func (r *JobRepository) Get(ctx context.Context, id string) (*models.Job, error) {
	row := r.db.QueryRowContext(ctx,
		`SELECT id, artist, album, path, status, source, created_at, finished_at, duration_ms, error_msg, files_total, files_processed
		 FROM jobs WHERE id = ?`, id)

	var job models.Job
	err := row.Scan(&job.ID, &job.Artist, &job.Album, &job.Path, &job.Status, &job.Source,
		&job.CreatedAt, &job.FinishedAt, &job.DurationMs, &job.ErrorMsg, &job.FilesTotal, &job.FilesProcessed)
	if err == sql.ErrNoRows {
		return nil, ErrNotFound
	}
	if err != nil {
		return nil, fmt.Errorf("get job: %w", err)
	}
	return &job, nil
}

func (r *JobRepository) List(ctx context.Context, params ListJobsParams) ([]models.Job, error) {
	query := `SELECT id, artist, album, path, status, source, created_at, finished_at, duration_ms, error_msg, files_total, files_processed
		 FROM jobs`
	args := []any{}

	if params.Status != nil {
		query += ` WHERE status = ?`
		args = append(args, *params.Status)
	}

	query += ` ORDER BY created_at DESC`

	if params.Limit > 0 {
		query += ` LIMIT ?`
		args = append(args, params.Limit)
	}
	if params.Offset > 0 {
		query += ` OFFSET ?`
		args = append(args, params.Offset)
	}

	rows, err := r.db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, fmt.Errorf("list jobs: %w", err)
	}
	defer rows.Close()

	var jobs []models.Job
	for rows.Next() {
		var job models.Job
		if err := rows.Scan(&job.ID, &job.Artist, &job.Album, &job.Path, &job.Status, &job.Source,
			&job.CreatedAt, &job.FinishedAt, &job.DurationMs, &job.ErrorMsg, &job.FilesTotal, &job.FilesProcessed); err != nil {
			return nil, fmt.Errorf("scan job: %w", err)
		}
		jobs = append(jobs, job)
	}
	return jobs, rows.Err()
}

func (r *JobRepository) Count(ctx context.Context, status *models.JobStatus) (int, error) {
	query := `SELECT COUNT(*) FROM jobs`
	args := []any{}

	if status != nil {
		query += ` WHERE status = ?`
		args = append(args, *status)
	}

	var count int
	err := r.db.QueryRowContext(ctx, query, args...).Scan(&count)
	if err != nil {
		return 0, fmt.Errorf("count jobs: %w", err)
	}
	return count, nil
}

func (r *JobRepository) UpdateProgress(ctx context.Context, id string, filesProcessed, filesTotal int) error {
	result, err := r.db.ExecContext(ctx,
		`UPDATE jobs SET files_processed = ?, files_total = ? WHERE id = ?`,
		filesProcessed, filesTotal, id,
	)
	if err != nil {
		return fmt.Errorf("update job progress: %w", err)
	}
	rows, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("rows affected: %w", err)
	}
	if rows == 0 {
		return ErrNotFound
	}
	return nil
}

func (r *JobRepository) UpdateStatus(ctx context.Context, id string, status models.JobStatus) error {
	result, err := r.db.ExecContext(ctx, `UPDATE jobs SET status = ? WHERE id = ?`, status, id)
	if err != nil {
		return fmt.Errorf("update job status: %w", err)
	}
	rows, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("rows affected: %w", err)
	}
	if rows == 0 {
		return ErrNotFound
	}
	return nil
}

func (r *JobRepository) Finish(ctx context.Context, id string, status models.JobStatus, durationMs int64, errMsg string) error {
	result, err := r.db.ExecContext(ctx,
		`UPDATE jobs SET status = ?, finished_at = ?, duration_ms = ?, error_msg = ? WHERE id = ?`,
		status, time.Now().UTC(), durationMs, errMsg, id,
	)
	if err != nil {
		return fmt.Errorf("finish job: %w", err)
	}
	rows, err := result.RowsAffected()
	if err != nil {
		return fmt.Errorf("rows affected: %w", err)
	}
	if rows == 0 {
		return ErrNotFound
	}
	return nil
}

func (r *JobRepository) ExpireStuck(ctx context.Context, statuses []models.JobStatus, olderThan time.Duration) (int, error) {
	if len(statuses) == 0 {
		return 0, nil
	}

	placeholders := make([]string, len(statuses))
	args := make([]any, 0, len(statuses)+1)
	for i, status := range statuses {
		placeholders[i] = "?"
		args = append(args, status)
	}
	args = append(args, time.Now().UTC().Add(-olderThan))

	query := fmt.Sprintf(
		`UPDATE jobs SET status = ?, finished_at = ?, error_msg = ? WHERE status IN (%s) AND created_at < ?`,
		strings.Join(placeholders, ","),
	)

	finalArgs := []any{models.StatusTimeout, time.Now().UTC(), "job timed out"}
	finalArgs = append(finalArgs, args...)

	result, err := r.db.ExecContext(ctx, query, finalArgs...)
	if err != nil {
		return 0, fmt.Errorf("expire stuck jobs: %w", err)
	}
	rows, err := result.RowsAffected()
	if err != nil {
		return 0, fmt.Errorf("rows affected: %w", err)
	}
	return int(rows), nil
}