package api

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

	"github.com/go-chi/chi/v5"
	"github.com/syonad/clonepack/internal/core"
	"github.com/syonad/clonepack/internal/store"
)

type SnapshotHandler struct {
	svc *core.SnapshotService
}

func NewSnapshotHandler(svc *core.SnapshotService) *SnapshotHandler {
	return &SnapshotHandler{svc: svc}
}

func (h *SnapshotHandler) Create(w http.ResponseWriter, r *http.Request) {
	repoID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid id")
		return
	}
	if err := Authorize(r.Context(), ActionSnapshotCreate, repoID); err != nil {
		Error(w, http.StatusForbidden, "forbidden")
		return
	}
	var req CreateSnapshotRequest
	json.NewDecoder(r.Body).Decode(&req)
	if req.Label == "" {
		req.Label = "manual-" + time.Now().UTC().Format(time.RFC3339)
	}
	id, err := h.svc.TakeSnapshot(r.Context(), repoID, req.Label)
	if errors.Is(err, store.ErrNotFound) {
		Error(w, http.StatusNotFound, "repo not found")
		return
	} else if err != nil {
		Error(w, http.StatusInternalServerError, err.Error())
		return
	}
	snap, _, _ := h.svc.Get(r.Context(), repoID, id)
	JSON(w, http.StatusCreated, snapshotToResponse(*snap))
}

func (h *SnapshotHandler) List(w http.ResponseWriter, r *http.Request) {
	repoID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid id")
		return
	}
	if err := Authorize(r.Context(), ActionSnapshotRead, repoID); err != nil {
		Error(w, http.StatusForbidden, "forbidden")
		return
	}
	snaps, err := h.svc.List(r.Context(), repoID)
	if errors.Is(err, store.ErrNotFound) {
		Error(w, http.StatusNotFound, "repo not found")
		return
	} else if err != nil {
		Error(w, http.StatusInternalServerError, err.Error())
		return
	}
	items := make([]SnapshotResponse, len(snaps))
	for i, s := range snaps {
		items[i] = snapshotToResponse(s)
	}
	JSON(w, http.StatusOK, ListSnapshotsResponse{Items: items, Total: len(items)})
}

func (h *SnapshotHandler) Get(w http.ResponseWriter, r *http.Request) {
	repoID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid id")
		return
	}
	snapID, err := strconv.ParseInt(chi.URLParam(r, "snap_id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid snap_id")
		return
	}
	if err := Authorize(r.Context(), ActionSnapshotRead, repoID); err != nil {
		Error(w, http.StatusForbidden, "forbidden")
		return
	}
	snap, pkgs, err := h.svc.Get(r.Context(), repoID, snapID)
	if errors.Is(err, store.ErrNotFound) {
		Error(w, http.StatusNotFound, "snapshot not found")
		return
	} else if err != nil {
		Error(w, http.StatusInternalServerError, err.Error())
		return
	}
	resp := SnapshotDetailResponse{
		SnapshotResponse: snapshotToResponse(*snap),
		Packages:         make([]SnapshotPackageResponse, len(pkgs)),
	}
	for i, p := range pkgs {
		resp.Packages[i] = snapshotPkgToResponse(p)
	}
	JSON(w, http.StatusOK, resp)
}

func (h *SnapshotHandler) Delete(w http.ResponseWriter, r *http.Request) {
	repoID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid id")
		return
	}
	snapID, err := strconv.ParseInt(chi.URLParam(r, "snap_id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid snap_id")
		return
	}
	if err := Authorize(r.Context(), ActionSnapshotDelete, repoID); err != nil {
		Error(w, http.StatusForbidden, "forbidden")
		return
	}
	if err := h.svc.Delete(r.Context(), repoID, snapID); errors.Is(err, store.ErrNotFound) {
		Error(w, http.StatusNotFound, "snapshot not found")
		return
	} else if err != nil {
		Error(w, http.StatusInternalServerError, err.Error())
		return
	}
	w.WriteHeader(http.StatusNoContent)
}

func (h *SnapshotHandler) Diff(w http.ResponseWriter, r *http.Request) {
	repoID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid id")
		return
	}
	if err := Authorize(r.Context(), ActionSnapshotRead, repoID); err != nil {
		Error(w, http.StatusForbidden, "forbidden")
		return
	}
	fromID, err := strconv.ParseInt(r.URL.Query().Get("from"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid from param")
		return
	}
	toID, err := strconv.ParseInt(r.URL.Query().Get("to"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid to param")
		return
	}
	diff, err := h.svc.Diff(r.Context(), repoID, fromID, toID)
	if errors.Is(err, store.ErrNotFound) {
		Error(w, http.StatusNotFound, "snapshot not found")
		return
	} else if err != nil {
		Error(w, http.StatusBadRequest, err.Error())
		return
	}
	resp := SnapshotDiffResponse{
		From:      snapshotToResponse(*diff.From),
		To:        snapshotToResponse(*diff.To),
		Unchanged: diff.Unchanged,
	}
	for _, p := range diff.Added {
		resp.Added = append(resp.Added, snapshotPkgToResponse(p))
	}
	for _, p := range diff.Removed {
		resp.Removed = append(resp.Removed, snapshotPkgToResponse(p))
	}
	JSON(w, http.StatusOK, resp)
}

func (h *SnapshotHandler) Rollback(w http.ResponseWriter, r *http.Request) {
	repoID, err := strconv.ParseInt(chi.URLParam(r, "id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid id")
		return
	}
	snapID, err := strconv.ParseInt(chi.URLParam(r, "snap_id"), 10, 64)
	if err != nil {
		Error(w, http.StatusBadRequest, "invalid snap_id")
		return
	}
	if err := Authorize(r.Context(), ActionSnapshotRollback, repoID); err != nil {
		Error(w, http.StatusForbidden, "forbidden")
		return
	}
	if err := h.svc.Rollback(r.Context(), repoID, snapID); errors.Is(err, store.ErrNotFound) {
		Error(w, http.StatusNotFound, "snapshot not found")
		return
	} else if err != nil {
		Error(w, http.StatusInternalServerError, err.Error())
		return
	}
	JSON(w, http.StatusOK, map[string]string{"status": "rollback completed"})
}

func snapshotToResponse(s store.Snapshot) SnapshotResponse {
	return SnapshotResponse{
		ID:        s.ID,
		RepoID:    s.RepoID,
		Label:     s.Label,
		CreatedAt: s.CreatedAt,
	}
}

func snapshotPkgToResponse(p store.SnapshotPackage) SnapshotPackageResponse {
	return SnapshotPackageResponse{
		ID:           p.ID,
		Name:         p.Name,
		Version:      p.Version,
		Arch:         p.Arch,
		Location:     p.Location,
		Checksum:     p.Checksum,
		ChecksumType: p.ChecksumType,
		Size:         p.Size,
	}
}