package handler

import (
	"database/sql"
	"errors"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"
	"github.com/wotra/wotra/internal/service"
)

// SettingsHandler serves /api/settings routes.
type SettingsHandler struct {
	svc *service.SettingsService
}

func NewSettingsHandler(svc *service.SettingsService) *SettingsHandler {
	return &SettingsHandler{svc: svc}
}

func (h *SettingsHandler) Routes(r chi.Router) {
	r.Get("/settings", h.Current)
	r.Put("/settings", h.Upsert)
	r.Get("/settings/history", h.History)
	r.Put("/settings/history/{id}", h.UpdateHistoryRow)
	r.Delete("/settings/history/{id}", h.DeleteHistoryRow)
}

// Current GET /api/settings
func (h *SettingsHandler) Current(w http.ResponseWriter, r *http.Request) {
	set, err := h.svc.Current(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	writeJSON(w, http.StatusOK, set)
}

// Upsert PUT /api/settings
func (h *SettingsHandler) Upsert(w http.ResponseWriter, r *http.Request) {
	var body struct {
		EffectiveFrom string  `json:"effective_from"`
		HoursPerWeek  float64 `json:"hours_per_week"`
		WorkdaysMask  int     `json:"workdays_mask"`
		Timezone      string  `json:"timezone"`
	}
	if err := decodeJSON(r, &body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON")
		return
	}
	set, err := h.svc.Upsert(r.Context(), service.UpsertSettingsInput{
		EffectiveFrom: body.EffectiveFrom,
		HoursPerWeek:  body.HoursPerWeek,
		WorkdaysMask:  body.WorkdaysMask,
		Timezone:      body.Timezone,
	})
	if err != nil {
		switch {
		case errors.Is(err, service.ErrInvalidHours), errors.Is(err, service.ErrInvalidWorkdaysMask):
			writeError(w, http.StatusUnprocessableEntity, err.Error())
		default:
			writeError(w, http.StatusInternalServerError, err.Error())
		}
		return
	}
	writeJSON(w, http.StatusOK, set)
}

// History GET /api/settings/history
func (h *SettingsHandler) History(w http.ResponseWriter, r *http.Request) {
	history, err := h.svc.History(r.Context())
	if err != nil {
		writeError(w, http.StatusInternalServerError, err.Error())
		return
	}
	if history == nil {
		writeJSON(w, http.StatusOK, []struct{}{})
		return
	}
	writeJSON(w, http.StatusOK, history)
}

// UpdateHistoryRow PUT /api/settings/history/{id}
func (h *SettingsHandler) UpdateHistoryRow(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid id")
		return
	}
	var body struct {
		EffectiveFrom string  `json:"effective_from"`
		HoursPerWeek  float64 `json:"hours_per_week"`
		WorkdaysMask  int     `json:"workdays_mask"`
		Timezone      string  `json:"timezone"`
	}
	if err := decodeJSON(r, &body); err != nil {
		writeError(w, http.StatusBadRequest, "invalid JSON")
		return
	}
	set, err := h.svc.UpdateSettings(r.Context(), id, service.UpdateSettingsInput{
		EffectiveFrom: body.EffectiveFrom,
		HoursPerWeek:  body.HoursPerWeek,
		WorkdaysMask:  body.WorkdaysMask,
		Timezone:      body.Timezone,
	})
	if err != nil {
		switch {
		case errors.Is(err, service.ErrSettingsNotFound), errors.Is(err, sql.ErrNoRows):
			writeError(w, http.StatusNotFound, err.Error())
		case errors.Is(err, service.ErrInvalidHours), errors.Is(err, service.ErrInvalidWorkdaysMask):
			writeError(w, http.StatusUnprocessableEntity, err.Error())
		default:
			writeError(w, http.StatusInternalServerError, err.Error())
		}
		return
	}
	writeJSON(w, http.StatusOK, set)
}

// DeleteHistoryRow DELETE /api/settings/history/{id}
func (h *SettingsHandler) DeleteHistoryRow(w http.ResponseWriter, r *http.Request) {
	id, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		writeError(w, http.StatusBadRequest, "invalid id")
		return
	}
	if err := h.svc.DeleteSettings(r.Context(), id); err != nil {
		switch {
		case errors.Is(err, service.ErrSettingsNotFound):
			writeError(w, http.StatusNotFound, err.Error())
		case errors.Is(err, service.ErrLastSettingsRow):
			writeError(w, http.StatusConflict, err.Error())
		default:
			writeError(w, http.StatusInternalServerError, err.Error())
		}
		return
	}
	w.WriteHeader(http.StatusNoContent)
}