local mp = require 'mp'
local utils = require 'mp.utils'

local originalVolume = 100

-- Fade volume from current to target in steps
local function fade_volume(target, steps, interval, callback)
    local current = tonumber(mp.get_property("volume"))
    local delta = (target - current) / steps
    local i = 0

    local function step()
        i = i + 1
        local newVolume = current + delta * i
        mp.set_property("volume", tostring(newVolume))
        if i < steps then
            mp.add_timeout(interval, step)
        elseif callback then
            callback()
        end
    end

    step()
end

function speak_metadata()
    originalVolume = tonumber(mp.get_property("volume")) or 100
    local targetVolume = math.max(originalVolume * 0.3, 1)

    -- Get message using playerctl
    local result = utils.subprocess({
        args = {"playerctl", "metadata", "-f", "{{artist}} - {{album}} - {{title}}"}
    })

    local msg
    if result.status == 0 and result.stdout and result.stdout:match("%S") then
        msg = result.stdout:gsub("\n", "")
    else
        local fallback = mp.get_property("media-title") or mp.get_property("filename/no-ext") or "unknown file"
        msg = "Now playing: " .. fallback
    end

    -- Fade down, speak via RHVoice, then fade up
    fade_volume(targetVolume, 10, 0.05, function()
        utils.subprocess({
            args = {"bash", "-c", string.format("echo %q | RHVoice-test -v 500 --", msg)}
        })
        fade_volume(originalVolume, 10, 0.05)
    end)
end

mp.add_key_binding("F1", "speak_metadata", speak_metadata)