/* Copyright Azareal 2017 - 2020 */
package common

import (
	"bytes"
	"encoding/json"
	"fmt"
	"html/template"
	"strings"
	"sync"
	"sync/atomic"

	min "git.tuxpa.in/a/gosora/common/templates"
	"git.tuxpa.in/a/gosora/uutils"
	"github.com/pkg/errors"
)

// TODO: Clean this file up
var Docks WidgetDocks
var widgetUpdateMutex sync.RWMutex

type WidgetDock struct {
    Items     []*Widget
    Scheduler *WidgetScheduler
}

type WidgetDocks struct {
    LeftOfNav    []*Widget
    RightOfNav   []*Widget
    LeftSidebar  WidgetDock
    RightSidebar WidgetDock
    //PanelLeft []Menus
    Footer WidgetDock
}

type WidgetMenu struct {
    Name     string
    MenuList []WidgetMenuItem
}

type WidgetMenuItem struct {
    Text     string
    Location string
    Compact  bool
}

type NameTextPair struct {
    Name string
    Text template.HTML
}

func preparseWidget(w *Widget, wdata string) (e error) {
    prebuildWidget := func(name string, data interface{}) (string, error) {
        var b bytes.Buffer
        e := DefaultTemplates.ExecuteTemplate(&b, name+".html", data)
        content := b.String()
        if Config.MinifyTemplates {
            content = min.Minify(content)
        }
        return content, e
    }

    sbytes := []byte(wdata)
    w.Literal = true
    // TODO: Split these hard-coded items out of this file and into the files for the individual widget types
    switch w.Type {
    case "simple", "about":
        var tmp NameTextPair
        e = json.Unmarshal(sbytes, &tmp)
        if e != nil {
            return e
        }
        w.Body, e = prebuildWidget("widget_"+w.Type, tmp)
    case "search_and_filter":
        w.Literal = false
        w.BuildFunc = widgetSearchAndFilter
    case "wol":
        w.Literal = false
        w.InitFunc = wolInit
        w.BuildFunc = wolRender
        w.TickFunc = wolTick
    case "wol_context":
        w.Literal = false
        w.BuildFunc = wolContextRender
    default:
        w.Body = wdata
    }

    // TODO: Test this
    // TODO: Should we toss this through a proper parser rather than crudely replacing it?
    rep := func(from, to string) {
        w.Location = strings.Replace(w.Location, from, to, -1)
    }
    rep(" ", "")
    rep("frontend", "!panel")
    rep("!!", "")

    // Skip blank zones
    locs := strings.Split(w.Location, "|")
    if len(locs) > 0 {
        w.Location = ""
        for _, loc := range locs {
            if loc == "" {
                continue
            }
            w.Location += loc + "|"
        }
        w.Location = w.Location[:len(w.Location)-1]
    }

    return e
}

func GetDockList() []string {
    return []string{
        "leftOfNav",
        "rightOfNav",
        "rightSidebar",
        "footer",
    }
}

func GetDock(dock string) []*Widget {
    switch dock {
    case "leftOfNav":
        return Docks.LeftOfNav
    case "rightOfNav":
        return Docks.RightOfNav
    case "rightSidebar":
        return Docks.RightSidebar.Items
    case "footer":
        return Docks.Footer.Items
    }
    return nil
}

func HasDock(dock string) bool {
    switch dock {
    case "leftOfNav", "rightOfNav", "rightSidebar", "footer":
        return true
    }
    return false
}

// TODO: Find a more optimimal way of doing this...
func HasWidgets(dock string, h *Header) bool {
    if !h.Theme.HasDock(dock) {
        return false
    }

    // Let themes forcibly override this slot
    sbody := h.Theme.BuildDock(dock)
    if sbody != "" {
        return true
    }

    var widgets []*Widget
    switch dock {
    case "leftOfNav":
        widgets = Docks.LeftOfNav
    case "rightOfNav":
        widgets = Docks.RightOfNav
    case "rightSidebar":
        widgets = Docks.RightSidebar.Items
    case "footer":
        widgets = Docks.Footer.Items
    }

    wcount := 0
    for _, widget := range widgets {
        if !widget.Enabled {
            continue
        }
        if widget.Allowed(h.Zone, h.ZoneID) {
            wcount++
        }
    }
    return wcount > 0
}

func BuildWidget(dock string, h *Header) (sbody string) {
    if !h.Theme.HasDock(dock) {
        return ""
    }
    // Let themes forcibly override this slot
    sbody = h.Theme.BuildDock(dock)
    if sbody != "" {
        return sbody
    }

    var widgets []*Widget
    switch dock {
    case "leftOfNav":
        widgets = Docks.LeftOfNav
    case "rightOfNav":
        widgets = Docks.RightOfNav
    case "topMenu":
        // 1 = id for the default menu
        mhold, e := Menus.Get(1)
        if e == nil {
            e := mhold.Build(h.Writer, h.CurrentUser, h.Path)
            if e != nil {
                LogError(e)
            }
        }
        return ""
    case "rightSidebar":
        widgets = Docks.RightSidebar.Items
    case "footer":
        widgets = Docks.Footer.Items
    }

    for _, widget := range widgets {
        if !widget.Enabled {
            continue
        }
        if widget.Allowed(h.Zone, h.ZoneID) {
            item, e := widget.Build(h)
            if e != nil {
                LogError(e)
            }
            sbody += item
        }
    }
    return sbody
}

var DockToID = map[string]int{
    "leftOfNav":    0,
    "rightOfNav":   1,
    "topMenu":      2,
    "rightSidebar": 3,
    "footer":       4,
}

func BuildWidget2(dock int, h *Header) (sbody string) {
    if !h.Theme.HasDockByID(dock) {
        return ""
    }
    // Let themes forcibly override this slot
    sbody = h.Theme.BuildDockByID(dock)
    if sbody != "" {
        return sbody
    }

    var widgets []*Widget
    switch dock {
    case 0:
        widgets = Docks.LeftOfNav
    case 1:
        widgets = Docks.RightOfNav
    case 2:
        // 1 = id for the default menu
        mhold, e := Menus.Get(1)
        if e == nil {
            e := mhold.Build(h.Writer, h.CurrentUser, h.Path)
            if e != nil {
                LogError(e)
            }
        }
        return ""
    case 3:
        widgets = Docks.RightSidebar.Items
    case 4:
        widgets = Docks.Footer.Items
    }

    for _, w := range widgets {
        if !w.Enabled {
            continue
        }
        if w.Allowed(h.Zone, h.ZoneID) {
            item, e := w.Build(h)
            if e != nil {
                LogError(e)
            }
            sbody += item
        }
    }
    return sbody
}

func BuildWidget3(dock int, h *Header) {
    if !h.Theme.HasDockByID(dock) {
        return
    }
    // Let themes forcibly override this slot
    if sbody := h.Theme.BuildDockByID(dock); sbody != "" {
        h.Writer.Write(uutils.StringToBytes(sbody))
        return
    }

    var widgets []*Widget
    switch dock {
    case 0:
        widgets = Docks.LeftOfNav
    case 1:
        widgets = Docks.RightOfNav
    case 2:
        // 1 = id for the default menu
        mhold, err := Menus.Get(1)
        if err == nil {
            err := mhold.Build(h.Writer, h.CurrentUser, h.Path)
            if err != nil {
                LogError(err)
            }
        }
        return
    case 3:
        widgets = Docks.RightSidebar.Items
    case 4:
        widgets = Docks.Footer.Items
    }

    for _, w := range widgets {
        if !w.Enabled {
            continue
        }
        if w.Allowed(h.Zone, h.ZoneID) {
            item, e := w.Build(h)
            if e != nil {
                LogError(e)
            }
            if item != "" {
                h.Writer.Write(uutils.StringToBytes(item))
            }
        }
    }
}

// TODO: Find a more optimimal way of doing this...
func HasWidgets2(dock int, h *Header) bool {
    if !h.Theme.HasDockByID(dock) {
        return false
    }

    // Let themes forcibly override this slot
    // TODO: Optimise this bit
    sbody := h.Theme.BuildDockByID(dock)
    if sbody != "" {
        return true
    }

    var widgets []*Widget
    switch dock {
    case 0:
        widgets = Docks.LeftOfNav
    case 1:
        widgets = Docks.RightOfNav
    case 3:
        widgets = Docks.RightSidebar.Items
    case 4:
        widgets = Docks.Footer.Items
    }

    wcount := 0
    for _, widget := range widgets {
        if !widget.Enabled {
            continue
        }
        if widget.Allowed(h.Zone, h.ZoneID) {
            wcount++
        }
    }
    return wcount > 0
}

func getDockWidgets(dock string) (widgets []*Widget, e error) {
    rows, e := widgetStmts.getDockList.Query(dock)
    if e != nil {
        return nil, e
    }
    defer rows.Close()

    for rows.Next() {
        w := &Widget{Position: 0, Side: dock}
        e = rows.Scan(&w.ID, &w.Position, &w.Type, &w.Enabled, &w.Location, &w.RawBody)
        if e != nil {
            return nil, e
        }
        e = preparseWidget(w, w.RawBody)
        if e != nil {
            return nil, e
        }
        Widgets.set(w)
        widgets = append(widgets, w)
    }
    return widgets, rows.Err()
}

// TODO: Make a store for this?
func InitWidgets() (fi error) {
    // TODO: Let themes set default values for widget docks, and let them lock in particular places with their stuff, e.g. leftOfNav and rightOfNav
    f := func(name string) {
        if fi != nil {
            return
        }
        dock, e := getDockWidgets(name)
        if e != nil {
            fi = e
            return
        }
        setDock(name, dock)
    }

    f("leftOfNav")
    f("rightOfNav")
    f("leftSidebar")
    f("rightSidebar")
    f("footer")
    if fi != nil {
        return fi
    }

    Tasks.Sec.Add(Docks.LeftSidebar.Scheduler.Tick)
    Tasks.Sec.Add(Docks.RightSidebar.Scheduler.Tick)
    Tasks.Sec.Add(Docks.Footer.Scheduler.Tick)

    return nil
}

func releaseWidgets(ws []*Widget) {
    for _, w := range ws {
        if w.ShutdownFunc != nil {
            w.ShutdownFunc(w)
        }
    }
}

// TODO: Use atomics
func setDock(dock string, widgets []*Widget) {
    dockHandle := func(dockWidgets []*Widget) {
        DebugLog(dock, widgets)
        releaseWidgets(dockWidgets)
    }
    dockHandle2 := func(dockWidgets WidgetDock) WidgetDock {
        dockHandle(dockWidgets.Items)
        if dockWidgets.Scheduler == nil {
            dockWidgets.Scheduler = &WidgetScheduler{}
        }
        for _, widget := range widgets {
            if widget.InitFunc != nil {
                widget.InitFunc(widget, dockWidgets.Scheduler)
            }
        }
        dockWidgets.Scheduler.Store()
        return WidgetDock{widgets, dockWidgets.Scheduler}
    }
    widgetUpdateMutex.Lock()
    defer widgetUpdateMutex.Unlock()
    switch dock {
    case "leftOfNav":
        dockHandle(Docks.LeftOfNav)
        Docks.LeftOfNav = widgets
    case "rightOfNav":
        dockHandle(Docks.RightOfNav)
        Docks.RightOfNav = widgets
    case "leftSidebar":
        Docks.LeftSidebar = dockHandle2(Docks.LeftSidebar)
    case "rightSidebar":
        Docks.RightSidebar = dockHandle2(Docks.RightSidebar)
    case "footer":
        Docks.Footer = dockHandle2(Docks.Footer)
    default:
        fmt.Printf("bad dock '%s'\n", dock)
        return
    }
}

type WidgetScheduler struct {
    widgets []*Widget
    store   atomic.Value
}

func (s *WidgetScheduler) Add(w *Widget) {
    s.widgets = append(s.widgets, w)
}

func (s *WidgetScheduler) Store() {
    s.store.Store(s.widgets)
}

func (s *WidgetScheduler) Tick() error {
    widgets := s.store.Load().([]*Widget)
    for _, widget := range widgets {
        if widget.TickFunc == nil {
            continue
        }
        e := widget.TickFunc(widget)
        if e != nil {
            return errors.WithStack(e)
        }
    }
    return nil
}