package database

import (
	"context"
	"fmt"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgxpool"
)

var ErrWorkflowAlreadyRunning = fmt.Errorf("workflow already running for this album and quality")

type WorkflowRun struct {
	ID           string
	AlbumID      string
	Quality      string
	Status       string
	ErrorMessage *string
	StartedAt    time.Time
	CompletedAt  *time.Time
	CreatedAt    time.Time
	UpdatedAt    time.Time
}

type WorkflowRunRepository struct {
	pool *pgxpool.Pool
}

func NewWorkflowRunRepository(pool *pgxpool.Pool) *WorkflowRunRepository {
	return &WorkflowRunRepository{pool: pool}
}

func (r *WorkflowRunRepository) Create(ctx context.Context, run *WorkflowRun) error {
	err := r.pool.QueryRow(ctx,
		`INSERT INTO workflow_runs (album_id, quality, status) VALUES ($1, $2, 'running')
		 ON CONFLICT ON CONSTRAINT idx_workflow_runs_active DO NOTHING
		 RETURNING id, started_at, created_at, updated_at`,
		run.AlbumID, run.Quality,
	).Scan(&run.ID, &run.StartedAt, &run.CreatedAt, &run.UpdatedAt)
	if err != nil {
		if err == pgx.ErrNoRows {
			return ErrWorkflowAlreadyRunning
		}
		return fmt.Errorf("creating workflow run: %w", err)
	}
	return nil
}

func (r *WorkflowRunRepository) SetCompleted(ctx context.Context, id string) error {
	_, err := r.pool.Exec(ctx,
		`UPDATE workflow_runs SET status = 'completed', completed_at = NOW(), updated_at = NOW() WHERE id = $1`, id,
	)
	if err != nil {
		return fmt.Errorf("setting workflow run completed: %w", err)
	}
	return nil
}

func (r *WorkflowRunRepository) SetFailed(ctx context.Context, id string, errorMsg string) error {
	_, err := r.pool.Exec(ctx,
		`UPDATE workflow_runs SET status = 'failed', error_message = $1, completed_at = NOW(), updated_at = NOW() WHERE id = $2`, errorMsg, id,
	)
	if err != nil {
		return fmt.Errorf("setting workflow run failed: %w", err)
	}
	return nil
}

func (r *WorkflowRunRepository) SetCancelled(ctx context.Context, id string) error {
	_, err := r.pool.Exec(ctx,
		`UPDATE workflow_runs SET status = 'cancelled', completed_at = NOW(), updated_at = NOW() WHERE id = $1`, id,
	)
	if err != nil {
		return fmt.Errorf("setting workflow run cancelled: %w", err)
	}
	return nil
}

func (r *WorkflowRunRepository) GetByAlbumAndQuality(ctx context.Context, albumID string, quality string) (*WorkflowRun, error) {
	run := &WorkflowRun{}
	err := r.pool.QueryRow(ctx,
		`SELECT id, album_id, quality, status, error_message, started_at, completed_at, created_at, updated_at
		 FROM workflow_runs WHERE album_id = $1 AND quality = $2 AND status = 'running' LIMIT 1`, albumID, quality,
	).Scan(&run.ID, &run.AlbumID, &run.Quality, &run.Status, &run.ErrorMessage, &run.StartedAt, &run.CompletedAt, &run.CreatedAt, &run.UpdatedAt)
	if err != nil {
		return nil, fmt.Errorf("getting workflow run by album and quality: %w", err)
	}
	return run, nil
}

func (r *WorkflowRunRepository) GetRunning(ctx context.Context) ([]*WorkflowRun, error) {
	rows, err := r.pool.Query(ctx,
		`SELECT id, album_id, quality, status, error_message, started_at, completed_at, created_at, updated_at
		 FROM workflow_runs WHERE status = 'running' ORDER BY started_at`,
	)
	if err != nil {
		return nil, fmt.Errorf("listing running workflow runs: %w", err)
	}
	defer rows.Close()

	var runs []*WorkflowRun
	for rows.Next() {
		run := &WorkflowRun{}
		if err := rows.Scan(&run.ID, &run.AlbumID, &run.Quality, &run.Status, &run.ErrorMessage, &run.StartedAt, &run.CompletedAt, &run.CreatedAt, &run.UpdatedAt); err != nil {
			return nil, fmt.Errorf("scanning workflow run: %w", err)
		}
		runs = append(runs, run)
	}
	return runs, nil
}

func (r *WorkflowRunRepository) GetByID(ctx context.Context, id string) (*WorkflowRun, error) {
	run := &WorkflowRun{}
	err := r.pool.QueryRow(ctx,
		`SELECT id, album_id, quality, status, error_message, started_at, completed_at, created_at, updated_at
		 FROM workflow_runs WHERE id = $1`, id,
	).Scan(&run.ID, &run.AlbumID, &run.Quality, &run.Status, &run.ErrorMessage, &run.StartedAt, &run.CompletedAt, &run.CreatedAt, &run.UpdatedAt)
	if err != nil {
		return nil, fmt.Errorf("getting workflow run by id: %w", err)
	}
	return run, nil
}