package genius

import (
	"context"
	"encoding/json"
	"errors"

	"github.com/jackc/pgx/v5"
	"pipu/api/internal/api/gen"
	"pipu/api/internal/auth"
	"pipu/api/internal/platform/apperr"
)

type Handler struct{ svc *Service }

func NewHandler(s *Service) *Handler { return &Handler{svc: s} }

func requireAdmin(ctx context.Context) error {
	p, ok := auth.PrincipalFrom(ctx)
	if !ok {
		return apperr.Unauthorized("auth.unauthorized", "authentication required")
	}
	if p.Role != auth.RoleAdmin {
		return apperr.Forbidden("auth.forbidden", "administrator required")
	}
	return nil
}

func (h *Handler) GetGeniusStats(ctx context.Context, _ gen.GetGeniusStatsRequestObject) (gen.GetGeniusStatsResponseObject, error) {
	if err := requireAdmin(ctx); err != nil {
		return nil, err
	}
	stats, err := h.svc.Stats(ctx)
	return gen.GetGeniusStats200JSONResponse(stats), err
}

func (h *Handler) ControlGenius(ctx context.Context, req gen.ControlGeniusRequestObject) (gen.ControlGeniusResponseObject, error) {
	if err := requireAdmin(ctx); err != nil {
		return nil, err
	}
	if !h.svc.configured {
		return nil, apperr.Conflict("genius.disabled", "configure GENIUS_ACCESS_TOKEN in deploy/.env")
	}
	if req.Body == nil {
		return nil, apperr.Validation("action", "validation.required", "action required", nil)
	}
	tx, err := h.svc.pool.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)
	switch string(req.Body.Action) {
	case "pause":
		_, err = tx.Exec(ctx, `UPDATE genius_state SET paused=true`)
	case "start":
		_, err = tx.Exec(ctx, `UPDATE genius_state SET paused=false,last_error=''`)
	case "retry":
		_, err = tx.Exec(ctx, `UPDATE genius_tracks SET status='pending',next_attempt=now(),last_error='' WHERE status IN ('error','partial','unmatched') AND locked_until<=now()`)
		if err == nil {
			_, err = tx.Exec(ctx, `UPDATE genius_state SET paused=false,last_error=''`)
		}
	default:
		return nil, apperr.Validation("action", "validation.invalid", "unknown action", nil)
	}
	if err != nil {
		return nil, err
	}
	if err = tx.Commit(ctx); err != nil {
		return nil, err
	}
	h.svc.Wake()
	stats, err := h.svc.Stats(ctx)
	return gen.ControlGenius200JSONResponse(stats), err
}

func (h *Handler) GetTrackGenius(ctx context.Context, req gen.GetTrackGeniusRequestObject) (gen.GetTrackGeniusResponseObject, error) {
	if _, ok := auth.PrincipalFrom(ctx); !ok {
		return nil, apperr.Unauthorized("auth.unauthorized", "authentication required")
	}
	content := emptyContent()
	var body []byte
	err := h.svc.pool.QueryRow(ctx, `SELECT COALESCE(g.content,'{}'),COALESCE(g.status,'pending') FROM tracks t LEFT JOIN genius_tracks g ON g.track_id=t.id WHERE t.id=$1`, req.Id).Scan(&body, &content.Status)
	if errors.Is(err, pgx.ErrNoRows) {
		return nil, apperr.NotFound("catalog.not_found", "track not found")
	}
	if err != nil {
		return nil, err
	}
	status := content.Status
	if err = json.Unmarshal(body, &content); err != nil {
		return nil, err
	}
	content.Status = status
	if !h.svc.configured && status == "pending" {
		content.Status = "disabled"
	}
	return gen.GetTrackGenius200JSONResponse(content), nil
}