local Sounds = {}

local sources = {}
local SAMPLE_RATE = 44100

local function makeSoundData(duration, generator)
    local samples = math.floor(SAMPLE_RATE * duration)
    local sd = love.sound.newSoundData(samples, SAMPLE_RATE, 16, 1)
    for i = 0, samples - 1 do
        local t = i / SAMPLE_RATE
        local p = i / samples
        sd:setSample(i, math.max(-1, math.min(1, generator(t, p))))
    end
    return sd
end

local function makeSource(sd)
    return love.audio.newSource(sd, "static")
end

local function genFire(t, p)
    local freq = 800 - p * 600
    local env = (1 - p) ^ 2
    return math.sin(2 * math.pi * freq * t) * env * 0.4
end

local function genEnemyFire(t, p)
    local freq = 400 - p * 250
    local env = (1 - p) ^ 2
    return math.sin(2 * math.pi * freq * t) * env * 0.35
end

local function genHitEnemy(t, p)
    local env = (1 - p) ^ 1.5
    local sine = math.sin(2 * math.pi * (80 + 40*(1-p)) * t) * 0.5
    local noise = (math.random() * 2 - 1) * 0.4
    return (sine + noise) * env * 0.5
end

local function genHitPlayer(t, p)
    local env = (1 - p) ^ 1.0
    local sine = math.sin(2 * math.pi * (50 + 30*(1-p)) * t) * 0.5
    local noise = (math.random() * 2 - 1) * 0.5
    local pulse = 0.7 + math.sin(2 * math.pi * 4 * t) * 0.3
    return (sine + noise) * env * pulse * 0.5
end

local function genEngine(t, p)
    local noise = (math.random() * 2 - 1) * 0.2
    local low = math.sin(2 * math.pi * 35 * t) * 0.15
    return (noise + low) * 0.3
end

local function genEnemyAppear(t, p)
    local freq = 200 + p * 300
    local env = 0.6
    if p < 0.1 then env = p / 0.1 * 0.6 end
    if p > 0.8 then env = (1 - p) / 0.2 * 0.6 end
    return math.sin(2 * math.pi * freq * t) * env * 0.3
end

local function genExtraLife(t, p)
    local freq
    if p < 0.33 then freq = 400
    elseif p < 0.66 then freq = 600
    else freq = 800 end
    local env = 0.7
    if p < 0.05 then env = p / 0.05 * 0.7 end
    if p > 0.9 then env = (1-p) / 0.1 * 0.7 end
    return math.sin(2 * math.pi * freq * t) * env * 0.35
end

local function genMissileLaunch(t, p)
    -- Rising whistle: frequency ramps up
    local freq = 300 + p * 900
    local env
    if p < 0.1 then env = p / 0.1
    elseif p > 0.8 then env = (1 - p) / 0.2
    else env = 1 end
    local tone = math.sin(2 * math.pi * freq * t)
    local noise = (math.random() * 2 - 1) * 0.1
    return (tone + noise) * env * 0.25
end

local function genScreenCrack(t, p)
    -- Glass break: noise burst + downward pitch sweep
    local env = (1 - p) ^ 1.5
    local noise = (math.random() * 2 - 1)
    local tone = math.sin(2 * math.pi * (1400 - p * 1200) * t)
    return (noise * 0.6 + tone * 0.2) * env * 0.45
end

local function genMotionBlocked(t, p)
    local env = (1 - p) ^ 2
    return math.sin(2 * math.pi * 160 * t) * env * 0.25
end

local function genSaucerHum(t, _)
    -- Long looping wavering tone — distinctive UFO cue
    local base = 220
    local vibrato = math.sin(2 * math.pi * 5 * t) * 12
    return math.sin(2 * math.pi * (base + vibrato) * t) * 0.22
end

function Sounds.init()
    sources = {}
    local defs = {
        fire           = {0.08, genFire},
        enemy_fire     = {0.1,  genEnemyFire},
        hit_enemy      = {0.4,  genHitEnemy},
        hit_player     = {0.8,  genHitPlayer},
        engine         = {0.3,  genEngine},
        enemy_appear   = {0.3,  genEnemyAppear},
        extra_life     = {0.3,  genExtraLife},
        missile_launch = {0.6,  genMissileLaunch},
        screen_crack   = {0.7,  genScreenCrack},
        motion_blocked = {0.12, genMotionBlocked},
    }
    for name, def in pairs(defs) do
        sources[name] = makeSource(makeSoundData(def[1], def[2]))
    end

    -- Saucer hum is a looping source (not cloned per-play) so it can be panned live
    local humData = makeSoundData(1.0, genSaucerHum)
    sources.saucer_hum = love.audio.newSource(humData, "static")
    sources.saucer_hum:setLooping(true)
    sources.saucer_hum:setRelative(false)
    sources.saucer_hum:setVolume(0.6)
    -- playMusic() silently no-ops if the music asset isn't bundled
end

function Sounds.play(name)
    local src = sources[name]
    if not src then return end
    src:clone():play()
end

function Sounds.startSaucerHum()
    local src = sources.saucer_hum
    if not src then return end
    if not src:isPlaying() then
        src:setPosition(0, 0, 0)
        src:play()
    end
end

function Sounds.stopSaucerHum()
    local src = sources.saucer_hum
    if src and src:isPlaying() then src:stop() end
end

function Sounds.updateSaucerHum(bearingRadians, distance)
    -- bearingRadians: atan2(side, forward) in player frame; 0 = straight ahead
    -- Map bearing sine to x pan, distance to attenuation via z distance
    local src = sources.saucer_hum
    if not src or not src:isPlaying() then return end
    local x = math.sin(bearingRadians) * 5
    local z = math.max(1, distance / 200)
    src:setPosition(x, 0, z)
end

function Sounds.playMusic(name)
    local path = "assets/music/" .. name .. ".ogg"
    if love.filesystem.getInfo and love.filesystem.getInfo(path) then
        local ok, src = pcall(love.audio.newSource, path, "stream")
        if ok and src then
            src:setLooping(false)
            src:play()
            sources["music_" .. name] = src
        end
    end
    -- Silently no-op if the asset isn't bundled
end

function Sounds.stopMusic()
    for k, src in pairs(sources) do
        if k:sub(1, 6) == "music_" and src.isPlaying and src:isPlaying() then
            src:stop()
        end
    end
end

return Sounds