package api

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

	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
	"git.fabledsword.com/bvandeusen/minstrel/internal/library"
)

// loudnessCoverageResp is the wire shape for GET /api/admin/library/loudness
// (M464 #4995). measured + silent + unreadable + pending = total; missing
// tracks are not counted. Enabled travels with the counts because with
// analysis off, pending never shrinks, and a gauge implying progress would be
// promising work nothing is doing.
type loudnessCoverageResp struct {
	Total      int64 `json:"total"`
	Measured   int64 `json:"measured"`
	Silent     int64 `json:"silent"`
	Unreadable int64 `json:"unreadable"`
	Pending    int64 `json:"pending"`
	Enabled    bool  `json:"enabled"`
}

// handleGetLoudnessCoverage implements GET /api/admin/library/loudness: how
// far the loudness backfill has got. Always 200; zeros on an empty library.
func (h *handlers) handleGetLoudnessCoverage(w http.ResponseWriter, r *http.Request) {
	row, err := library.LoudnessCoverage(r.Context(), h.pool)
	if err != nil {
		writeErrWithLog(w, h.logger, "admin: get loudness coverage", apierror.InternalMsg("lookup failed", err))
		return
	}
	writeJSON(w, http.StatusOK, loudnessCoverageResp{
		Total:      row.Total,
		Measured:   row.Measured,
		Silent:     row.Silent,
		Unreadable: row.Unreadable,
		Pending:    row.Pending,
		Enabled:    h.loudnessSettings.Get().Enabled,
	})
}

// loudnessSettingsBody is the wire shape for GET and PUT
// /api/admin/library/loudness-settings.
type loudnessSettingsBody struct {
	Enabled             bool  `json:"enabled"`
	BackfillConcurrency int32 `json:"backfill_concurrency"`
	LeveledCacheMB      int32 `json:"leveled_cache_mb"`
}

func loudnessSettingsBodyOf(s library.LoudnessSettings) loudnessSettingsBody {
	return loudnessSettingsBody{
		Enabled:             s.Enabled,
		BackfillConcurrency: s.BackfillConcurrency,
		LeveledCacheMB:      s.LeveledCacheMB,
	}
}

// handleGetLoudnessSettings implements GET /api/admin/library/loudness-settings.
func (h *handlers) handleGetLoudnessSettings(w http.ResponseWriter, _ *http.Request) {
	writeJSON(w, http.StatusOK, loudnessSettingsBodyOf(h.loudnessSettings.Get()))
}

// handleUpdateLoudnessSettings implements PUT /api/admin/library/loudness-settings.
// A whole-row write: a body that leaves out the concurrency decodes it as zero,
// which is refused rather than saved.
func (h *handlers) handleUpdateLoudnessSettings(w http.ResponseWriter, r *http.Request) {
	var req loudnessSettingsBody
	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
		writeErr(w, apierror.BadRequest("invalid_body", "malformed JSON"))
		return
	}
	saved, err := h.loudnessSettings.Set(r.Context(), library.LoudnessSettings{
		Enabled:             req.Enabled,
		BackfillConcurrency: req.BackfillConcurrency,
		LeveledCacheMB:      req.LeveledCacheMB,
	})
	if err != nil {
		if errors.Is(err, library.ErrLoudnessSettingOutOfRange) {
			writeErr(w, apierror.BadRequest("invalid_setting", err.Error()))
			return
		}
		writeErrWithLog(w, h.logger, "admin loudness settings: update failed", apierror.Internal(err))
		return
	}
	writeJSON(w, http.StatusOK, loudnessSettingsBodyOf(saved))
}