package api

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

	"github.com/go-chi/chi/v5"

	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarr"
	"git.fabledsword.com/bvandeusen/minstrel/internal/lidarrrequests"
)

// validRequestStatuses is the set of allowed values for the ?status= param.
var validRequestStatuses = map[string]bool{
	"pending":   true,
	"approved":  true,
	"rejected":  true,
	"completed": true,
	"failed":    true,
}

// handleListAdminRequests implements GET /api/admin/requests.
// ?status= defaults to "pending"; ?limit= defaults to 50, max 200.
func (h *handlers) handleListAdminRequests(w http.ResponseWriter, r *http.Request) {
	status := r.URL.Query().Get("status")
	if status == "" {
		status = "pending"
	}
	if !validRequestStatuses[status] {
		writeAdminJSONErr(w, http.StatusBadRequest, "invalid_status")
		return
	}

	limitStr := r.URL.Query().Get("limit")
	limit := 50
	if limitStr != "" {
		v, err := strconv.Atoi(limitStr)
		if err != nil || v <= 0 {
			writeAdminJSONErr(w, http.StatusBadRequest, "invalid_limit")
			return
		}
		if v > 200 {
			v = 200
		}
		limit = v
	}

	rows, err := h.lidarrRequests.ListByStatus(r.Context(), status, int32(limit))
	if err != nil {
		h.logger.Error("admin: list requests", "err", err)
		writeAdminJSONErr(w, http.StatusInternalServerError, "server_error")
		return
	}

	q := dbq.New(h.pool)
	out := make([]requestView, 0, len(rows))
	for _, row := range rows {
		v := requestViewFrom(row)
		fillProgress(r.Context(), q, row, &v)
		out = append(out, v)
	}
	writeJSON(w, http.StatusOK, out)
}

// approveRequestBody is the optional JSON body for POST /api/admin/requests/:id/approve.
type approveRequestBody struct {
	QualityProfileID int    `json:"quality_profile_id"`
	RootFolderPath   string `json:"root_folder_path"`
}

// handleApproveRequest implements POST /api/admin/requests/:id/approve.
func (h *handlers) handleApproveRequest(w http.ResponseWriter, r *http.Request) {
	admin, ok := auth.UserFromContext(r.Context())
	if !ok {
		writeAdminJSONErr(w, http.StatusUnauthorized, "unauthorized")
		return
	}

	id, ok := parseUUID(chi.URLParam(r, "id"))
	if !ok {
		writeAdminJSONErr(w, http.StatusBadRequest, "invalid_id")
		return
	}

	var body approveRequestBody
	// Body is entirely optional; ignore decode errors.
	_ = json.NewDecoder(r.Body).Decode(&body)

	row, err := h.lidarrRequests.Approve(r.Context(), id, admin.ID, lidarrrequests.ApproveOverrides{
		QualityProfileID: body.QualityProfileID,
		RootFolderPath:   body.RootFolderPath,
	})
	if err != nil {
		switch {
		case errors.Is(err, lidarrrequests.ErrLidarrDisabled):
			writeAdminJSONErr(w, http.StatusServiceUnavailable, "lidarr_disabled")
		case errors.Is(err, lidarrrequests.ErrDefaultsIncomplete):
			writeAdminJSONErr(w, http.StatusBadRequest, "lidarr_defaults_incomplete")
		case errors.Is(err, lidarrrequests.ErrNotFound):
			writeAdminJSONErr(w, http.StatusNotFound, "request_not_found")
		case errors.Is(err, lidarrrequests.ErrNotPending):
			writeAdminJSONErr(w, http.StatusConflict, "request_not_pending")
		case errors.Is(err, lidarr.ErrUnreachable):
			writeAdminJSONErr(w, http.StatusServiceUnavailable, "lidarr_unreachable")
		case errors.Is(err, lidarr.ErrAuthFailed):
			writeAdminJSONErr(w, http.StatusServiceUnavailable, "lidarr_auth_failed")
		case errors.Is(err, lidarr.ErrServerError):
			// Lidarr itself 5xx'd — its response body is in err's wrapped
			// message (see lidarr.readBodySnippet). Logged below for ops.
			h.logger.Error("admin: approve request: lidarr 5xx", "err", err)
			writeAdminJSONErr(w, http.StatusBadGateway, "lidarr_server_error")
		case errors.Is(err, lidarr.ErrLookupFailed):
			// Lidarr returned 4xx — usually "artist already exists" or
			// "no metadata found." Log so ops can see the actual reason.
			h.logger.Warn("admin: approve request: lidarr 4xx", "err", err)
			writeAdminJSONErr(w, http.StatusBadGateway, "lidarr_rejected")
		default:
			h.logger.Error("admin: approve request", "err", err)
			writeAdminJSONErr(w, http.StatusInternalServerError, "server_error")
		}
		return
	}

	h.publishRequestStatusChanged(row)
	writeJSON(w, http.StatusOK, requestViewFrom(row))
}

// rejectRequestBody is the optional JSON body for POST /api/admin/requests/:id/reject.
type rejectRequestBody struct {
	Notes string `json:"notes"`
}

// handleRejectRequest implements POST /api/admin/requests/:id/reject.
func (h *handlers) handleRejectRequest(w http.ResponseWriter, r *http.Request) {
	admin, ok := auth.UserFromContext(r.Context())
	if !ok {
		writeAdminJSONErr(w, http.StatusUnauthorized, "unauthorized")
		return
	}

	id, ok := parseUUID(chi.URLParam(r, "id"))
	if !ok {
		writeAdminJSONErr(w, http.StatusBadRequest, "invalid_id")
		return
	}

	var body rejectRequestBody
	_ = json.NewDecoder(r.Body).Decode(&body)

	row, err := h.lidarrRequests.Reject(r.Context(), id, admin.ID, body.Notes)
	if err != nil {
		switch {
		case errors.Is(err, lidarrrequests.ErrNotFound):
			writeAdminJSONErr(w, http.StatusNotFound, "request_not_found")
		case errors.Is(err, lidarrrequests.ErrNotPending):
			writeAdminJSONErr(w, http.StatusConflict, "request_not_pending")
		default:
			h.logger.Error("admin: reject request", "err", err)
			writeAdminJSONErr(w, http.StatusInternalServerError, "server_error")
		}
		return
	}

	h.publishRequestStatusChanged(row)
	writeJSON(w, http.StatusOK, requestViewFrom(row))
}
