local awful = require "awful"
local phosphor = require "assets.phosphor"
local qbind = require "quarrel.bind"
local qmarkup = require "quarrel.markup"
local qui = require "quarrel.ui"
local qvars = require "quarrel.vars"
local wibox = require "wibox"

local weekday_map = { 7, 1, 2, 3, 4, 5, 6 }

local calendar = wibox.widget(qui.styled {
    widget = wibox.container.background,
    {
        widget = wibox.container.margin,
        margins = qvars.big_padding,
        {
            {
                {
                    widget = wibox.container.place,
                    qui.icon {
                        icon = phosphor.caret_left_bold,
                    },
                },
                {
                    widget = wibox.container.place,
                    {
                        widget = wibox.widget.textbox,
                        text = "January 2024",
                    },
                },
                {
                    widget = wibox.container.place,
                    qui.icon {
                        icon = phosphor.caret_right_bold,
                    },
                },
                layout = wibox.layout.align.horizontal,
                expand = "outside",
            },
            {
                layout = wibox.layout.grid,
                forced_num_rows = 7,
                forced_num_cols = 7,
                spacing = qvars.padding,
                id = "grid",
            },
            layout = wibox.layout.fixed.vertical,
            spacing = qvars.big_padding,
        },
    },
})

-- Logic heavily inspired by https://github.com/Sinomor/dotfiles/blob/e409f9a84bf40daf1e39c0179ec749232ed827c9/home/.config/awesome/ui/control/moment/calendar.lua#L134-L173
function calendar:compute_grid(year, month)
    local calendar_table = { {}, {}, {}, {}, {}, {} }
    local current = os.date("*t", os.time())
    local first_day = os.date("*t", os.time { year = year, month = month, day = 1 })
    local last_day = os.date("*t", os.time { year = year, month = month + 1, day = 0 })

    local days = last_day.day

    local prev_days = os.date("*t", os.time { year = year, month = month, day = 0 })
    local prev_offset = weekday_map[first_day.wday] - 1
    local prev_month = month - 1 == -1 and 12 or month - 1
    local prev_year = prev_month == 12 and year - 1 or year

    if prev_offset ~= -1 then
        for offset = prev_offset, 1, -1 do
            local day = prev_days.day - offset + 1
            table.insert(
                calendar_table[1],
                { day, day == current.day and prev_month == current.month and prev_year == current.year, false }
            )
        end
    end

    do
        local row = 1
        local weekday = weekday_map[first_day.wday]
        for day = 1, days do
            table.insert(
                calendar_table[row],
                { day, day == current.day and month == current.month and year == current.year, true }
            )
            if weekday == 7 then
                row = row + 1
                weekday = 1
            else
                weekday = weekday + 1
            end
        end

        local next_month = month + 1 == 13 and 1 or month + 1
        local next_year = next_month == 1 and year + 1 or year
        for day = 1, 42 - prev_offset - days do
            table.insert(
                calendar_table[row],
                { day, day == current.day and next_month + 1 == current.month and next_year == current.year, false }
            )
            if weekday == 7 then
                row = row + 1
                weekday = 1
            else
                weekday = weekday + 1
            end
        end
    end

    for i, row in ipairs(calendar_table) do
        for j, col in ipairs(row) do
            local widget = self:get_children_by_id("grid")[1]:get_widgets_at(i + 1, j)[1]
            widget.widget.widget.text = col[1]
            if col[2] then
                widget.bg = qvars.colors.yellow
                widget.fg = qvars.colors.bg
            else
                widget.bg = qvars.colors.bg
                widget.fg = col[3] and qvars.colors.fg or qvars.colors.dim.fg
            end
        end
    end
end

local cells = {}
local function cell(content)
    local widget = wibox.widget {
        widget = wibox.container.background,
        shape = qvars.shape,
        {
            widget = wibox.container.place,
            forced_height = qvars.char_height * 1.5,
            forced_width = qvars.char_height * 1.5,
            {
                widget = wibox.widget.textbox,
                markup = content,
            },
        },
    }
    table.insert(cells, widget)
end

cell "Mo"
cell "Tu"
cell "We"
cell "Th"
cell "Fr"
cell(qmarkup("Sa", { bold = true }))
cell(qmarkup("Su", { bold = true }))

for _ = 1, 42 do
    cell()
end
calendar:get_children_by_id("grid")[1]:add(table.unpack(cells))
calendar:compute_grid(2024, 1)

return calendar