package api

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

	"github.com/lerko/nib/internal/db"
)

type ErrorResponse struct {
	Error   string `json:"error"`
	Message string `json:"message"`
}

type EntityResponse struct {
	ID          string   `json:"id"`
	CreatedAt   string   `json:"created_at"`
	ModifiedAt  string   `json:"modified_at"`
	Body        string   `json:"body"`
	Title       *string  `json:"title"`
	Description *string  `json:"description"`
	Glyph       string   `json:"glyph"`
	TimeAnchor  *string  `json:"time_anchor"`
	CompletedAt *string  `json:"completed_at"`
	Pinned      bool     `json:"pinned"`
	DeletedAt   *string  `json:"deleted_at"`
	Tags        []string `json:"tags"`
	CardType    *string  `json:"card_type"`
	CardData    *string  `json:"card_data"`
	UseCount    int      `json:"use_count"`
	LastUsedAt  *string  `json:"last_used_at"`
}

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, code, message string) {
	writeJSON(w, status, ErrorResponse{Error: code, Message: message})
}

func decodeJSON(w http.ResponseWriter, r *http.Request, dst any) bool {
	if err := json.NewDecoder(r.Body).Decode(dst); err != nil {
		writeError(w, http.StatusBadRequest, "invalid_input", "malformed JSON: "+err.Error())
		return false
	}
	return true
}

func entityToResponse(e *db.Entity) EntityResponse {
	resp := EntityResponse{
		ID:          e.ID,
		CreatedAt:   e.CreatedAt.Format(time.RFC3339),
		ModifiedAt:  e.ModifiedAt.Format(time.RFC3339),
		Body:        e.Body,
		Title:       e.Title,
		Description: e.Description,
		Glyph:       string(e.Glyph),
		Pinned:      e.Pinned,
		Tags:        e.Tags,
		UseCount:    e.UseCount,
	}
	if resp.Tags == nil {
		resp.Tags = []string{}
	}
	resp.TimeAnchor = e.TimeAnchor
	resp.CompletedAt = formatTimeRespPtr(e.CompletedAt)
	resp.DeletedAt = formatTimeRespPtr(e.DeletedAt)
	resp.LastUsedAt = formatTimeRespPtr(e.LastUsedAt)
	if e.CardType != nil {
		s := string(*e.CardType)
		resp.CardType = &s
	}
	resp.CardData = e.CardData
	return resp
}

func formatTimeRespPtr(t *time.Time) *string {
	if t == nil {
		return nil
	}
	s := t.Format(time.RFC3339)
	return &s
}