package api

import (
	"encoding/json"
	"errors"
	"net/http"

	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
	"git.fabledsword.com/bvandeusen/minstrel/internal/reacquisition"
)

// reacquisitionSettingsResp is the admin card's payload (milestone #290).
//
// Carries more than the stored settings: [UnnameableAlbums] is the count of
// albums with missing files that can never be auto-requested because neither
// they nor their artist has an MBID. The card states that number rather than
// leaving the operator to wonder why some rows never get a request — a
// feature that silently does nothing for part of its input reads as broken.
type reacquisitionSettingsResp struct {
	Enabled          bool  `json:"enabled"`
	GraceHours       int32 `json:"grace_hours"`
	BackoffBaseHours int32 `json:"backoff_base_hours"`
	BackoffMaxHours  int32 `json:"backoff_max_hours"`
	MaxAttempts      int32 `json:"max_attempts"`
	MaxPerPass       int32 `json:"max_per_pass"`
	AutoApprove      bool  `json:"auto_approve"`

	UnnameableAlbums int64 `json:"unnameable_albums"`
}

// handleGetReacquisitionSettings implements GET /api/admin/library/reacquisition.
func (h *handlers) handleGetReacquisitionSettings(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, http.StatusOK, h.reacquisitionPayload(r))
}

// handleUpdateReacquisitionSettings implements PUT /api/admin/library/reacquisition.
func (h *handlers) handleUpdateReacquisitionSettings(w http.ResponseWriter, r *http.Request) {
	var req reacquisitionSettingsResp
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeErr(w, apierror.BadRequest("invalid_body", "malformed JSON"))
		return
	}
	_, err := h.reacqSettings.Set(r.Context(), reacquisition.Settings{
		Enabled:          req.Enabled,
		GraceHours:       req.GraceHours,
		BackoffBaseHours: req.BackoffBaseHours,
		BackoffMaxHours:  req.BackoffMaxHours,
		MaxAttempts:      req.MaxAttempts,
		MaxPerPass:       req.MaxPerPass,
		AutoApprove:      req.AutoApprove,
	})
	if err != nil {
		// The Go-side validation mirrors migration 0056's CHECKs so the
		// operator gets a readable message naming the field, rather than a
		// constraint-violation string leaking through as a 500.
		if errors.Is(err, reacquisition.ErrOutOfRange) {
			writeErr(w, apierror.BadRequest("invalid_setting", err.Error()))
			return
		}
		writeErrWithLog(w, h.logger, "admin reacquisition: update failed", apierror.Internal(err))
		return
	}
	// Echo the payload recomputed under the new values so the card reflects
	// what it just did without a reload.
	writeJSON(w, http.StatusOK, h.reacquisitionPayload(r))
}

func (h *handlers) reacquisitionPayload(r *http.Request) reacquisitionSettingsResp {
	cur := h.reacqSettings.Get()
	out := reacquisitionSettingsResp{
		Enabled:          cur.Enabled,
		GraceHours:       cur.GraceHours,
		BackoffBaseHours: cur.BackoffBaseHours,
		BackoffMaxHours:  cur.BackoffMaxHours,
		MaxAttempts:      cur.MaxAttempts,
		MaxPerPass:       cur.MaxPerPass,
		AutoApprove:      cur.AutoApprove,
	}
	// Best-effort: the settings are the point of this endpoint, and failing
	// the whole card because a count query hiccuped would be the wrong trade.
	if n, err := dbq.New(h.pool).CountAlbumsMissingWithoutMbid(r.Context()); err == nil {
		out.UnnameableAlbums = n
	} else {
		h.logger.Warn("admin reacquisition: unnameable count failed", "err", err)
	}
	return out
}