-- Simple widgets for screens

local _ENV = mkmodule('gui.widgets')

local gui = require('gui')
local utils = require('utils')

local dscreen = dfhack.screen

local function show_view(view,vis)
    if view then
        view.visible = vis
    end
end

local function getval(obj)
    if type(obj) == 'function' then
        return obj()
    else
        return obj
    end
end

local function map_opttab(tab,idx)
    if tab then
        return tab[idx]
    else
        return idx
    end
end

------------
-- Widget --
------------

Widget = defclass(Widget, gui.View)

Widget.ATTRS {
    frame = DEFAULT_NIL,
    frame_inset = DEFAULT_NIL,
    frame_background = DEFAULT_NIL,
}

function Widget:computeFrame(parent_rect)
    local sw, sh = parent_rect.width, parent_rect.height
    return gui.compute_frame_body(sw, sh, self.frame, self.frame_inset)
end

function Widget:onRenderFrame(dc, rect)
    if self.frame_background then
        dc:fill(rect, self.frame_background)
    end
end

-----------
-- Panel --
-----------

Panel = defclass(Panel, Widget)

Panel.ATTRS {
    on_render = DEFAULT_NIL,
}

function Panel:init(args)
    self:addviews(args.subviews)
end

function Panel:onRenderBody(dc)
    if self.on_render then self.on_render(dc) end
end

-----------
-- Pages --
-----------

Pages = defclass(Pages, Panel)

function Pages:init(args)
    for _,v in ipairs(self.subviews) do
        v.visible = false
    end
    self:setSelected(args.selected or 1)
end

function Pages:setSelected(idx)
    if type(idx) ~= 'number' then
        local key = idx
        if type(idx) == 'string' then
            key = self.subviews[key]
        end
        idx = utils.linear_index(self.subviews, key)
        if not idx then
            error('Unknown page: '..key)
        end
    end

    show_view(self.subviews[self.selected], false)
    self.selected = math.min(math.max(1, idx), #self.subviews)
    show_view(self.subviews[self.selected], true)
end

function Pages:getSelected()
    return self.selected, self.subviews[self.selected]
end

----------------
-- Edit field --
----------------

EditField = defclass(EditField, Widget)

EditField.ATTRS{
    text = '',
    text_pen = DEFAULT_NIL,
    on_char = DEFAULT_NIL,
    on_change = DEFAULT_NIL,
    on_submit = DEFAULT_NIL,
}

function EditField:onRenderBody(dc)
    dc:pen(self.text_pen or COLOR_LIGHTCYAN):fill(0,0,dc.width-1,0)

    local cursor = '_'
    if not self.active or gui.blink_visible(300) then
        cursor = ' '
    end
    local txt = self.text .. cursor
    if #txt > dc.width then
        txt = string.char(27)..string.sub(txt, #txt-dc.width+2)
    end
    dc:string(txt)
end

function EditField:onInput(keys)
    if self.on_submit and keys.SELECT then
        self.on_submit(self.text)
        return true
    elseif keys._STRING then
        local old = self.text
        if keys._STRING == 0 then
            self.text = string.sub(old, 1, #old-1)
        else
            local cv = string.char(keys._STRING)
            if not self.on_char or self.on_char(cv, old) then
                self.text = old .. cv
            end
        end
        if self.on_change and self.text ~= old then
            self.on_change(self.text, old)
        end
        return true
    end
end

-----------
-- Label --
-----------

function parse_label_text(obj)
    local text = obj.text or {}
    if type(text) ~= 'table' then
        text = { text }
    end
    local curline = nil
    local out = { }
    local active = nil
    local idtab = nil
    for _,v in ipairs(text) do
        local vv
        if type(v) == 'string' then
            vv = utils.split_string(v, NEWLINE)
        else
            vv = { v }
        end

        for i = 1,#vv do
            local cv = vv[i]
            if i > 1 then
                if not curline then
                    table.insert(out, {})
                end
                curline = nil
            end
            if cv ~= '' then
                if not curline then
                    curline = {}
                    table.insert(out, curline)
                end

                if type(cv) == 'string' then
                    table.insert(curline, { text = cv })
                else
                    table.insert(curline, cv)

                    if cv.on_activate then
                        active = active or {}
                        table.insert(active, cv)
                    end

                    if cv.id then
                        idtab = idtab or {}
                        idtab[cv.id] = cv
                    end
                end
            end
        end
    end
    obj.text_lines = out
    obj.text_active = active
    obj.text_ids = idtab
end

local function is_disabled(token)
    return (token.disabled ~= nil and getval(token.disabled)) or
           (token.enabled ~= nil and not getval(token.enabled))
end

function render_text(obj,dc,x0,y0,pen,dpen,disabled)
    local width = 0
    for iline,line in ipairs(obj.text_lines) do
        local x = 0
        if dc then
            dc:seek(x+x0,y0+iline-1)
        end
        for _,token in ipairs(line) do
            token.line = iline
            token.x1 = x

            if token.gap then
                x = x + token.gap
                if dc then
                    dc:advance(token.gap)
                end
            end

            if token.tile then
                x = x + 1
                if dc then
                    dc:char(nil, token.tile)
                end
            end

            if token.text or token.key then
                local text = getval(token.text) or ''
                local keypen

                if dc then
                    local tpen = getval(token.pen)
                    if disabled or is_disabled(token) then
                        dc:pen(getval(token.dpen) or tpen or dpen)
                        keypen = COLOR_GREEN
                    else
                        dc:pen(tpen or pen)
                        keypen = COLOR_LIGHTGREEN
                    end
                end

                x = x + #text

                if token.key then
                    local keystr = gui.getKeyDisplay(token.key)
                    local sep = token.key_sep or ''

                    x = x + #keystr

                    if sep == '()' then
                        if dc then
                            dc:string(text)
                            dc:string(' ('):string(keystr,keypen):string(')')
                        end
                        x = x + 3
                    else
                        if dc then
                            dc:string(keystr,keypen):string(sep):string(text)
                        end
                        x = x + #sep
                    end
                else
                    if dc then
                        dc:string(text)
                    end
                end
            end

            token.x2 = x
        end
        width = math.max(width, x)
    end
    obj.text_width = width
end

function check_text_keys(self, keys)
    if self.text_active then
        for _,item in ipairs(self.text_active) do
            if item.key and keys[item.key] and not is_disabled(item) then
                item.on_activate()
                return true
            end
        end
    end
end

Label = defclass(Label, Widget)

Label.ATTRS{
    text_pen = COLOR_WHITE,
    text_dpen = COLOR_DARKGREY,
    disabled = DEFAULT_NIL,
    enabled = DEFAULT_NIL,
    auto_height = true,
    auto_width = false,
}

function Label:init(args)
    self:setText(args.text)
end

function Label:setText(text)
    self.text = text
    parse_label_text(self)

    if self.auto_height then
        self.frame = self.frame or {}
        self.frame.h = self:getTextHeight()
    end
end

function Label:preUpdateLayout()
    if self.auto_width then
        self.frame = self.frame or {}
        self.frame.w = self:getTextWidth()
    end
end

function Label:itemById(id)
    if self.text_ids then
        return self.text_ids[id]
    end
end

function Label:getTextHeight()
    return #self.text_lines
end

function Label:getTextWidth()
    render_text(self)
    return self.text_width
end

function Label:onRenderBody(dc)
    render_text(self,dc,0,0,self.text_pen,self.text_dpen,is_disabled(self))
end

function Label:onInput(keys)
    if not is_disabled(self) then
        return check_text_keys(self, keys)
    end
end

----------
-- List --
----------

List = defclass(List, Widget)

STANDARDSCROLL = {
    STANDARDSCROLL_UP = -1,
    STANDARDSCROLL_DOWN = 1,
    STANDARDSCROLL_PAGEUP = '-page',
    STANDARDSCROLL_PAGEDOWN = '+page',
}

SECONDSCROLL = {
    SECONDSCROLL_UP = -1,
    SECONDSCROLL_DOWN = 1,
    SECONDSCROLL_PAGEUP = '-page',
    SECONDSCROLL_PAGEDOWN = '+page',
}

List.ATTRS{
    text_pen = COLOR_CYAN,
    cursor_pen = COLOR_LIGHTCYAN,
    inactive_pen = DEFAULT_NIL,
    on_select = DEFAULT_NIL,
    on_submit = DEFAULT_NIL,
    row_height = 1,
    scroll_keys = STANDARDSCROLL,
    icon_width = DEFAULT_NIL,
}

function List:init(info)
    self.page_top = 1
    self.page_size = 1
    self:setChoices(info.choices, info.selected)
end

function List:setChoices(choices, selected)
    self.choices = choices or {}

    for i,v in ipairs(self.choices) do
        if type(v) ~= 'table' then
            v = { text = v }
            self.choices[i] = v
        end
        v.text = v.text or v.caption or v[1]
        parse_label_text(v)
    end

    self:setSelected(selected)
end

function List:setSelected(selected)
    self.selected = selected or self.selected or 1
    self:moveCursor(0, true)
    return self.selected
end

function List:getChoices()
    return self.choices
end

function List:getSelected()
    if #self.choices > 0 then
        return self.selected, self.choices[self.selected]
    end
end

function List:getContentWidth()
    local width = 0
    for i,v in ipairs(self.choices) do
        render_text(v)
        local roww = v.text_width
        if v.key then
            roww = roww + 3 + #gui.getKeyDisplay(v.key)
        end
        width = math.max(width, roww)
    end
    return width + (self.icon_width or 0)
end

function List:getContentHeight()
    return #self.choices * self.row_height
end

function List:postComputeFrame(body)
    self.page_size = math.max(1, math.floor(body.height / self.row_height))
    self:moveCursor(0)
end

function List:moveCursor(delta, force_cb)
    local page = math.max(1, self.page_size)
    local cnt = #self.choices

    if cnt < 1 then
        self.page_top = 1
        self.selected = 1
        return
    end

    local off = self.selected+delta-1
    local ds = math.abs(delta)

    if ds > 1 then
        if off >= cnt+ds-1 then
            off = 0
        else
            off = math.min(cnt-1, off)
        end
        if off <= -ds then
            off = cnt-1
        else
            off = math.max(0, off)
        end
    end

    self.selected = 1 + off % cnt
    self.page_top = 1 + page * math.floor((self.selected-1) / page)

    if (force_cb or delta ~= 0) and self.on_select then
        self.on_select(self:getSelected())
    end
end

function List:onRenderBody(dc)
    local choices = self.choices
    local top = self.page_top
    local iend = math.min(#choices, top+self.page_size-1)
    local iw = self.icon_width

    for i = top,iend do
        local obj = choices[i]
        local current = (i == self.selected)
        local cur_pen = self.cursor_pen
        local cur_dpen = self.text_pen

        if not self.active then
            cur_pen = self.inactive_pen or self.cursor_pen
        end

        local y = (i - top)*self.row_height

        if iw and obj.icon then
            local icon = getval(obj.icon)
            if icon then
                dc:seek(0, y)
                if type(icon) ~= 'string' then
                    dc:char(nil,icon)
                else
                    if current then
                        dc:string(icon, obj.icon_pen or self.icon_pen or cur_pen)
                    else
                        dc:string(icon, obj.icon_pen or self.icon_pen or cur_dpen)
                    end
                end
            end
        end

        render_text(obj, dc, iw or 0, y, cur_pen, cur_dpen, not current)

        if obj.key then
            local keystr = gui.getKeyDisplay(obj.key)
            dc:seek(dc.width-2-#keystr,y):pen(self.text_pen)
            dc:string('('):string(keystr,COLOR_LIGHTGREEN):string(')')
        end
    end
end

function List:submit()
    if self.on_submit and #self.choices > 0 then
        self.on_submit(self:getSelected())
    end
end

function List:onInput(keys)
    if self.on_submit and keys.SELECT then
        self:submit()
        return true
    else
        for k,v in pairs(self.scroll_keys) do
            if keys[k] then
                if v == '+page' then
                    v = self.page_size
                elseif v == '-page' then
                    v = -self.page_size
                end

                self:moveCursor(v)
                return true
            end
        end

        for i,v in ipairs(self.choices) do
            if v.key and keys[v.key] then
                self:setSelected(i)
                self:submit()
                return true
            end
        end

        local current = self.choices[self.selected]
        if current then
            return check_text_keys(current, keys)
        end
    end
end

-------------------
-- Filtered List --
-------------------

FilteredList = defclass(FilteredList, Widget)

function FilteredList:init(info)
    self.edit = EditField{
        text_pen = info.edit_pen or info.cursor_pen,
        frame = { l = info.icon_width, t = 0 },
        on_change = self:callback('onFilterChange'),
        on_char = self:callback('onFilterChar'),
    }
    self.list = List{
        frame = { t = 2 },
        text_pen = info.text_pen,
        cursor_pen = info.cursor_pen,
        inactive_pen = info.inactive_pen,
        icon_pen = info.icon_pen,
        row_height = info.row_height,
        scroll_keys = info.scroll_keys,
        icon_width = info.icon_width,
    }
    if info.on_select then
        self.list.on_select = function()
            return info.on_select(self:getSelected())
        end
    end
    if info.on_submit then
        self.list.on_submit = function()
            return info.on_submit(self:getSelected())
        end
    end
    self.not_found = Label{
        visible = false,
        text = info.not_found_label or 'No matches',
        text_pen = COLOR_LIGHTRED,
        frame = { l = info.icon_width, t = 2 },
    }
    self:addviews{ self.edit, self.list, self.not_found }
    self:setChoices(info.choices, info.selected)
end

function FilteredList:getChoices()
    return self.choices
end

function FilteredList:setChoices(choices, pos)
    choices = choices or {}
    self.choices = choices
    self.edit.text = ''
    self.list:setChoices(choices, pos)
    self.not_found.visible = (#choices == 0)
end

function FilteredList:submit()
    return self.list:submit()
end

function FilteredList:canSubmit()
    return not self.not_found.visible
end

function FilteredList:getSelected()
    local i,v = self.list:getSelected()
    if i then
        return map_opttab(self.choice_index, i), v
    end
end

function FilteredList:getContentWidth()
    return self.list:getContentWidth()
end

function FilteredList:getContentHeight()
    return self.list:getContentHeight() + 2
end

function FilteredList:getFilter()
    return self.edit.text, self.list.choices
end

function FilteredList:setFilter(filter, pos)
    local choices = self.choices
    local cidx = nil

    filter = filter or ''
    self.edit.text = filter

    if filter ~= '' then
        local tokens = utils.split_string(filter, ' ')
        local ipos = pos

        choices = {}
        cidx = {}
        pos = nil

        for i,v in ipairs(self.choices) do
            local ok = true
            local search_key = v.search_key or v.text
            for _,key in ipairs(tokens) do
                if key ~= '' and not string.match(search_key, '%f[^%s\x00]'..key) then
                    ok = false
                    break
                end
            end
            if ok then
                table.insert(choices, v)
                cidx[#choices] = i
                if ipos == i then
                    pos = #choices
                end
            end
        end
    end

    self.choice_index = cidx
    self.list:setChoices(choices, pos)
    self.not_found.visible = (#choices == 0)
end

function FilteredList:onFilterChange(text)
    self:setFilter(text)
end

local bad_chars = {
    ['%'] = true, ['.'] = true, ['+'] = true, ['*'] = true,
    ['['] = true, [']'] = true, ['('] = true, [')'] = true,
}

function FilteredList:onFilterChar(char, text)
    if bad_chars[char] then
        return false
    end
    if char == ' ' then
        return string.match(text, '%S$')
    end
    return true
end

return _ENV