package api

import (
	"errors"
	"fmt"
	"net/http"
	"regexp"
	"strings"

	"provisioning/internal/config"
	"provisioning/internal/events"
	"provisioning/internal/image"
	"provisioning/internal/model"
	"provisioning/internal/orchestrator"
	"provisioning/internal/pxe"
	"provisioning/internal/statemachine"
	"provisioning/internal/store"

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

type UI struct {
	Hosts        *store.Hosts
	Ops          *store.Operations
	Locks        *store.Locks
	Images       *store.Images
	Activity     *store.Activity
	ImageSvc     *image.Service
	Runner       *orchestrator.Runner
	Orchestrator *orchestrator.HostOrchestrator
	Hub          *events.Hub
	PXE          *pxe.Supervisor
	Config       *config.Config
	ServerTypes  *config.ServerTypeRegistry
}

func (u *UI) Dashboard(w http.ResponseWriter, r *http.Request) {
	hosts, _ := u.Hosts.List(r.Context())
	renderHTML(w, dashboardPage(hosts))
}

func (u *UI) NewHostForm(w http.ResponseWriter, r *http.Request) {
	types := u.ServerTypes.Keys()
	renderHTML(w, hostFormPage(types, "", nil))
}

func (u *UI) CreateHost(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, "bad form", http.StatusBadRequest)
		return
	}
	hostname := strings.TrimSpace(r.FormValue("hostname"))
	mac := strings.TrimSpace(r.FormValue("mac"))
	serverType := r.FormValue("server_type")
	notes := r.FormValue("notes")

	var errs []string
	if hostname == "" {
		errs = append(errs, "Hostname is required")
	}
	if !isValidMAC(mac) {
		errs = append(errs, "Invalid MAC address format (expected xx:xx:xx:xx:xx:xx)")
	}
	if _, ok := u.ServerTypes.Get(serverType); !ok {
		errs = append(errs, "Invalid server type")
	}
	if len(errs) > 0 {
		types := u.ServerTypes.Keys()
		renderHTML(w, hostFormPage(types, strings.Join(errs, "; "), &model.Host{
			Hostname:   hostname,
			MAC:        mac,
			ServerType: serverType,
			Notes:      notes,
		}))
		return
	}
	if existing, err := u.Hosts.GetByHostname(r.Context(), hostname); err == nil && existing != nil {
		errs = append(errs, "A host with this hostname already exists")
	}
	if existing, err := u.Hosts.GetByMAC(r.Context(), mac); err == nil && existing != nil {
		errs = append(errs, "A host with this MAC address already exists")
	}
	if len(errs) > 0 {
		types := u.ServerTypes.Keys()
		renderHTML(w, hostFormPage(types, strings.Join(errs, "; "), &model.Host{
			Hostname:   hostname,
			MAC:        mac,
			ServerType: serverType,
			Notes:      notes,
		}))
		return
	}

	_, err := u.Hosts.Create(r.Context(), model.Host{
		Hostname:   hostname,
		MAC:        mac,
		ServerType: serverType,
		Notes:      notes,
	})
	if err != nil {
		types := u.ServerTypes.Keys()
		renderHTML(w, hostFormPage(types, "Host already exists: "+err.Error(), nil))
		return
	}

	hosts, _ := u.Hosts.List(r.Context())
	_ = u.PXE.Reload(hosts)
	http.Redirect(w, r, "/", http.StatusSeeOther)
}

func (u *UI) HostDetail(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)

	host, err := u.Hosts.Get(r.Context(), id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			http.Error(w, "Host not found", http.StatusNotFound)
			return
		}
		http.Error(w, "Internal error", http.StatusInternalServerError)
		return
	}
	ops, _ := u.Ops.ListByHost(r.Context(), host.ID)
	activity, _ := u.Activity.ListByHost(r.Context(), host.ID, 50)
	renderHTML(w, hostDetailPage(host, ops, activity))
}

func (u *UI) OperationDetail(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)

	op, err := u.Ops.Get(r.Context(), id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			http.Error(w, "Operation not found", http.StatusNotFound)
			return
		}
		http.Error(w, "Internal error", http.StatusInternalServerError)
		return
	}
	host, _ := u.Hosts.Get(r.Context(), op.HostID)
	activity, _ := u.Activity.ListByOperation(r.Context(), op.ID, 100)
	renderHTML(w, operationDetailPage(op, host, activity))
}

func (u *UI) CancelOperation(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)

	op, err := u.Ops.Get(r.Context(), id)
	if err != nil {
		if errors.Is(err, store.ErrNotFound) {
			http.Error(w, "Operation not found", http.StatusNotFound)
			return
		}
		http.Error(w, "Internal error", http.StatusInternalServerError)
		return
	}
	if op.State != model.OpActive {
		http.Redirect(w, r, fmt.Sprintf("/ops/%d", id), http.StatusSeeOther)
		return
	}
	u.Runner.FailHost(r.Context(), op.HostID, "cancelled by user")
	http.Redirect(w, r, fmt.Sprintf("/ops/%d", id), http.StatusSeeOther)
}

func (u *UI) TriggerRebuild(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)

	host, err := u.Hosts.Get(r.Context(), id)
	if err != nil {
		http.Error(w, "Host not found", http.StatusNotFound)
		return
	}

	locked, _ := u.Locks.IsLocked(r.Context(), host.ID)
	if locked {
		http.Redirect(w, r, fmt.Sprintf("/hosts/%d", id), http.StatusSeeOther)
		return
	}

	opID, _ := u.Ops.Create(r.Context(), model.Operation{
		HostID: host.ID,
		Kind:   model.OpRebuildProxmox,
	})
	_ = u.Locks.Acquire(r.Context(), host.ID, opID)
	u.Runner.LogActivity(r.Context(), host.ID, model.LogInfo, "ui", "Rebuild triggered by user")

	if err := u.Orchestrator.PrepareRebuild(r.Context(), host.ID); err != nil {
		_ = u.Locks.Release(r.Context(), host.ID)
		http.Error(w, "Failed to prepare rebuild: "+err.Error(), http.StatusInternalServerError)
		return
	}

	u.Runner.Transition(r.Context(), host.ID, statemachine.TriggerRebuildRequested)

	hosts, _ := u.Hosts.List(r.Context())
	_ = u.PXE.Reload(hosts)

	http.Redirect(w, r, fmt.Sprintf("/hosts/%d", id), http.StatusSeeOther)
}

func (u *UI) DeleteHost(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)

	_ = u.Hosts.Delete(r.Context(), id)
	hosts, _ := u.Hosts.List(r.Context())
	_ = u.PXE.Reload(hosts)
	http.Redirect(w, r, "/", http.StatusSeeOther)
}

func (u *UI) ImagesPage(w http.ResponseWriter, r *http.Request) {
	images, _ := u.Images.List(r.Context())
	renderHTML(w, imagesPage(images))
}

func (u *UI) NewImageForm(w http.ResponseWriter, r *http.Request) {
	renderHTML(w, imageUploadForm(""))
}

func (u *UI) UploadImage(w http.ResponseWriter, r *http.Request) {
	isXHR := r.Header.Get("X-Requested-With") == "XMLHttpRequest"

	if err := r.ParseMultipartForm(0); err != nil {
		if isXHR {
			writeJSON(w, http.StatusBadRequest, map[string]any{"ok": false, "error": "Invalid form submission"})
		} else {
			renderHTML(w, imageUploadForm("Invalid form submission"))
		}
		return
	}

	name := strings.TrimSpace(r.FormValue("name"))
	version := strings.TrimSpace(r.FormValue("version"))
	kind := strings.TrimSpace(r.FormValue("kind"))
	uploadID := strings.TrimSpace(r.FormValue("upload_id"))

	file, _, err := r.FormFile("iso")
	if err != nil {
		if isXHR {
			writeJSON(w, http.StatusBadRequest, map[string]any{"ok": false, "error": "ISO file is required"})
		} else {
			renderHTML(w, imageUploadForm("ISO file is required"))
		}
		return
	}
	defer file.Close()

	var progressFn image.ProgressFunc
	if uploadID != "" {
		progressFn = func(stage, detail string) {
			u.Hub.Publish(events.Event{
				Name:    "image.upload_progress",
				Payload: fmt.Sprintf(`{"upload_id":%q,"stage":%q,"detail":%q}`, uploadID, stage, detail),
			})
		}
	}

	_, err = u.ImageSvc.Upload(r.Context(), image.UploadParams{
		Name:       name,
		Kind:       kind,
		Version:    version,
		ISO:        file,
		OnProgress: progressFn,
	})
	if err != nil {
		if isXHR {
			writeJSON(w, http.StatusInternalServerError, map[string]any{"ok": false, "error": err.Error()})
		} else {
			renderHTML(w, imageUploadForm(err.Error()))
		}
		return
	}

	if isXHR {
		writeJSON(w, http.StatusOK, map[string]any{"ok": true})
	} else {
		http.Redirect(w, r, "/images", http.StatusSeeOther)
	}
}

func (u *UI) SetDefaultImage(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)
	_ = u.Images.SetDefault(r.Context(), id)
	http.Redirect(w, r, "/images", http.StatusSeeOther)
}

func (u *UI) DeleteImage(w http.ResponseWriter, r *http.Request) {
	idStr := chi.URLParam(r, "id")
	var id int64
	fmt.Sscanf(idStr, "%d", &id)
	_ = u.ImageSvc.Delete(r.Context(), id)
	http.Redirect(w, r, "/images", http.StatusSeeOther)
}

var macRegex = regexp.MustCompile(`^([0-9a-fA-F]{2}[:\-]){5}[0-9a-fA-F]{2}$`)

func isValidMAC(mac string) bool {
	return macRegex.MatchString(strings.TrimSpace(mac))
}