// Weekly schedule and blocklist/allowlist editors (AGENTS.md §5 screens 3–4,
// §11 Phase 6). Only the Control Service writes desired state, so every save
// goes through the store, is audited, and republishes the device's retained
// config.
package web

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"gitea.lab.audasmedia.com.au/sam/internet_use_control/internal/store"
)

// defaultScheduleSlots is how many windows a day shows in the weekly grid. The
// grid grows if a device already has more, so a save never drops a window.
const defaultScheduleSlots = 3

// maxScheduleSlots bounds how many window slots the editor reads back from a
// submitted form.
const maxScheduleSlots = 12

// editorCommon carries the fields every editor page shares with the app shell.
type editorCommon struct {
	Title         string
	Heading       string
	Sub           string
	Username      string
	CSRF          string
	Version       string
	AppEnv        string
	DeviceID      int64
	DeviceName    string
	PlatformLabel string
	Error         string
	Flash         string
}

// ---------- weekly schedule ----------

type scheduleSlotView struct {
	Start string
	End   string
}

type scheduleRowView struct {
	Weekday int
	Name    string
	Slots   []scheduleSlotView
}

type scheduleEditorData struct {
	editorCommon
	Rows         []scheduleRowView
	ActiveNow    bool
	ActiveUntil  string
	NextBoundary string
}

func buildScheduleRows(schedules []store.Schedule, minSlots int) []scheduleRowView {
	byDay := make([][]scheduleSlotView, 7)
	maxDay := 0
	for _, sc := range schedules {
		if sc.Weekday < store.Monday || sc.Weekday > store.Sunday {
			continue
		}
		byDay[sc.Weekday] = append(byDay[sc.Weekday], scheduleSlotView{Start: sc.Start, End: sc.End})
		if len(byDay[sc.Weekday]) > maxDay {
			maxDay = len(byDay[sc.Weekday])
		}
	}
	slots := minSlots
	if maxDay > slots {
		slots = maxDay
	}
	rows := make([]scheduleRowView, 0, 7)
	for d := store.Monday; d <= store.Sunday; d++ {
		row := scheduleRowView{Weekday: d, Name: store.WeekdayName(d)}
		for i := 0; i < slots; i++ {
			var slot scheduleSlotView
			if i < len(byDay[d]) {
				slot = byDay[d][i]
			}
			row.Slots = append(row.Slots, slot)
		}
		rows = append(rows, row)
	}
	return rows
}

func rowsFromWindows(windows []store.ScheduleWindow) []scheduleRowView {
	schedules := make([]store.Schedule, 0, len(windows))
	for _, w := range windows {
		schedules = append(schedules, store.Schedule{Weekday: w.Weekday, Start: w.Start, End: w.End})
	}
	return buildScheduleRows(schedules, defaultScheduleSlots)
}

func (s *Server) handleScheduleEditor(w http.ResponseWriter, r *http.Request) {
	id, ok := s.deviceID(w, r)
	if !ok {
		return
	}
	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
	defer cancel()

	dev, err := s.store.GetDevice(ctx, id)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}
	schedules, err := s.store.ListSchedules(ctx, id)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}
	s.renderScheduleEditor(w, r, dev, buildScheduleRows(schedules, defaultScheduleSlots),
		strings.TrimSpace(r.URL.Query().Get("err")),
		strings.TrimSpace(r.URL.Query().Get("ok")))
}

func (s *Server) renderScheduleEditor(w http.ResponseWriter, r *http.Request, dev *store.Device, rows []scheduleRowView, errMsg, flash string) {
	ctx, cancel := context.WithTimeout(r.Context(), 2*time.Second)
	defer cancel()

	data := scheduleEditorData{
		editorCommon: editorCommon{
			Title:         "Schedule — " + dev.Name,
			Heading:       "Weekly schedule",
			Sub:           fmt.Sprintf("%s · %s", dev.Name, platformLabel(dev.Platform)),
			Username:      s.cfg.AdminUsername,
			CSRF:          s.auth.EnsureCSRF(w, r),
			Version:       s.cfg.Version,
			AppEnv:        s.cfg.AppEnv,
			DeviceID:      dev.ID,
			DeviceName:    dev.Name,
			PlatformLabel: platformLabel(dev.Platform),
			Error:         errMsg,
			Flash:         flash,
		},
		Rows: rows,
	}
	now := s.now()
	if schedules, err := s.store.ListSchedules(ctx, dev.ID); err == nil {
		if active, until := store.ScheduleActive(schedules, now); active && until != nil {
			data.ActiveNow = true
			data.ActiveUntil = until.In(s.loc()).Format("Mon 02 Jan 15:04")
		}
		if boundary := store.NextWindowBoundary(schedules, now); boundary != nil {
			data.NextBoundary = boundary.In(s.loc()).Format("Mon 02 Jan 15:04")
		}
	}
	s.render(w, r, "schedule-editor.html", data)
}

func (s *Server) handleScheduleSave(w http.ResponseWriter, r *http.Request) {
	id, ok := s.deviceID(w, r)
	if !ok {
		return
	}
	if !s.requireCSRF(w, r) {
		return
	}
	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
	defer cancel()

	dev, err := s.store.GetDevice(ctx, id)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}

	var windows []store.ScheduleWindow
	if r.PostFormValue("clear") == "" {
		for weekday := store.Monday; weekday <= store.Sunday; weekday++ {
			for slot := 0; slot < maxScheduleSlots; slot++ {
				start := r.PostFormValue(fmt.Sprintf("start_%d_%d", weekday, slot))
				end := r.PostFormValue(fmt.Sprintf("end_%d_%d", weekday, slot))
				if strings.TrimSpace(start) == "" && strings.TrimSpace(end) == "" {
					continue
				}
				windows = append(windows, store.ScheduleWindow{Weekday: weekday, Start: start, End: end})
			}
		}
	}

	if err := s.store.ReplaceSchedules(ctx, id, windows, s.cfg.AdminUsername); err != nil {
		s.log.Warn("schedule rejected", "device", dev.Name, "err", err)
		s.renderScheduleEditor(w, r, dev, rowsFromWindows(windows), err.Error(), "")
		return
	}
	s.log.Info("schedule saved", "device", dev.Name, "windows", len(windows))
	s.publishConfig(ctx, *dev)
	http.Redirect(w, r, fmt.Sprintf("/devices/%d/schedule?ok=%s", id,
		url.QueryEscape("Saved schedule for "+dev.Name)), http.StatusSeeOther)
}

// ---------- blocklist / allowlist ----------

type listEntryView struct {
	ID        int64
	Kind      string
	KindLabel string
	Value     string
}

type listsEditorData struct {
	editorCommon
	PlatformHint string
	Block        []listEntryView
	Allow        []listEntryView
}

func listEntryViews(entries []store.ListEntry) []listEntryView {
	out := make([]listEntryView, 0, len(entries))
	for _, e := range entries {
		out = append(out, listEntryView{
			ID:        e.ID,
			Kind:      e.Kind,
			KindLabel: e.Kind,
			Value:     e.Value,
		})
	}
	return out
}

func platformHint(platform string) string {
	switch platform {
	case store.PlatformAndroid:
		return "App values are Android package names (for example com.spotify.music). Site values are hostnames (for example youtube.com)."
	case store.PlatformWindows:
		return "App values are Windows process names (for example chrome.exe). Site values are hostnames (for example youtube.com)."
	default:
		return "App values are package or process names. Site values are hostnames."
	}
}

func (s *Server) handleListsEditor(w http.ResponseWriter, r *http.Request) {
	id, ok := s.deviceID(w, r)
	if !ok {
		return
	}
	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
	defer cancel()

	dev, err := s.store.GetDevice(ctx, id)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}
	s.renderListsEditor(w, r, dev,
		strings.TrimSpace(r.URL.Query().Get("err")),
		strings.TrimSpace(r.URL.Query().Get("ok")))
}

func (s *Server) renderListsEditor(w http.ResponseWriter, r *http.Request, dev *store.Device, errMsg, flash string) {
	ctx, cancel := context.WithTimeout(r.Context(), 2*time.Second)
	defer cancel()

	block, err := s.store.ListEntries(ctx, dev.ID, store.TableBlocklist)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}
	allow, err := s.store.ListEntries(ctx, dev.ID, store.TableAllowlist)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}

	s.render(w, r, "lists-editor.html", listsEditorData{
		editorCommon: editorCommon{
			Title:         "Lists — " + dev.Name,
			Heading:       "Blocklist and allowlist",
			Sub:           fmt.Sprintf("%s · %s", dev.Name, platformLabel(dev.Platform)),
			Username:      s.cfg.AdminUsername,
			CSRF:          s.auth.EnsureCSRF(w, r),
			Version:       s.cfg.Version,
			AppEnv:        s.cfg.AppEnv,
			DeviceID:      dev.ID,
			DeviceName:    dev.Name,
			PlatformLabel: platformLabel(dev.Platform),
			Error:         errMsg,
			Flash:         flash,
		},
		PlatformHint: platformHint(dev.Platform),
		Block:        listEntryViews(block),
		Allow:        listEntryViews(allow),
	})
}

// listTableFromForm maps the editor's "block"/"allow" field to the store's
// table constant.
func listTableFromForm(value string) (string, error) {
	switch strings.TrimSpace(value) {
	case "block", store.TableBlocklist:
		return store.TableBlocklist, nil
	case "allow", store.TableAllowlist:
		return store.TableAllowlist, nil
	default:
		return "", errors.New("list must be block or allow")
	}
}

func (s *Server) handleListAdd(w http.ResponseWriter, r *http.Request) {
	id, ok := s.deviceID(w, r)
	if !ok {
		return
	}
	if !s.requireCSRF(w, r) {
		return
	}
	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
	defer cancel()

	dev, err := s.store.GetDevice(ctx, id)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}
	table, err := listTableFromForm(r.PostFormValue("table"))
	if err != nil {
		http.Redirect(w, r, fmt.Sprintf("/devices/%d/lists?err=%s", id,
			url.QueryEscape(err.Error())), http.StatusSeeOther)
		return
	}
	kind := strings.ToLower(strings.TrimSpace(r.PostFormValue("kind")))
	value := r.PostFormValue("value")

	entry, err := s.store.AddListEntry(ctx, id, table, kind, value, s.cfg.AdminUsername)
	if err != nil {
		s.log.Warn("list entry rejected", "device", dev.Name, "err", err)
		http.Redirect(w, r, fmt.Sprintf("/devices/%d/lists?err=%s", id,
			url.QueryEscape(err.Error())), http.StatusSeeOther)
		return
	}
	s.log.Info("list entry added", "device", dev.Name, "list", table, "kind", entry.Kind, "value", entry.Value)
	s.publishConfig(ctx, *dev)
	http.Redirect(w, r, fmt.Sprintf("/devices/%d/lists?ok=%s", id,
		url.QueryEscape("Added "+entry.Value)), http.StatusSeeOther)
}

func (s *Server) handleListDelete(w http.ResponseWriter, r *http.Request) {
	id, ok := s.deviceID(w, r)
	if !ok {
		return
	}
	entryID, err := strconv.ParseInt(r.PathValue("entryID"), 10, 64)
	if err != nil || entryID <= 0 {
		http.NotFound(w, r)
		return
	}
	if !s.requireCSRF(w, r) {
		return
	}
	ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
	defer cancel()

	dev, err := s.store.GetDevice(ctx, id)
	if err != nil {
		s.deviceLookupError(w, r, err)
		return
	}
	table, err := listTableFromForm(r.PostFormValue("table"))
	if err != nil {
		http.Redirect(w, r, fmt.Sprintf("/devices/%d/lists?err=%s", id,
			url.QueryEscape(err.Error())), http.StatusSeeOther)
		return
	}
	if err := s.store.DeleteListEntry(ctx, id, entryID, table, s.cfg.AdminUsername); err != nil {
		if errors.Is(err, store.ErrNotFound) {
			http.NotFound(w, r)
			return
		}
		s.deviceLookupError(w, r, err)
		return
	}
	s.log.Info("list entry removed", "device", dev.Name, "list", table, "entry", entryID)
	s.publishConfig(ctx, *dev)
	http.Redirect(w, r, fmt.Sprintf("/devices/%d/lists?ok=%s", id,
		url.QueryEscape("Removed entry")), http.StatusSeeOther)
}