local World = require("game.world")
local Palette = require("rendering.palette")

local Lander = {}

-- Physics tuned to match original Lunar Lander feel:
-- Gentle lunar gravity, thrust comfortably overcomes it,
-- deliberate rotation, fuel lasts long enough to learn
local GRAVITY = 12          -- gentle lunar pull (original was ~1/6 earth)
local THRUST_ACCEL = 36     -- about 3x gravity — can hover and climb
local ROT_SPEED = 1.4       -- ~80 deg/sec — deliberate, not twitchy
local FUEL_RATE = 6          -- fuel per second — 750 gives ~125 sec of thrust
local MAX_SPEED = 120        -- terminal velocity cap

-- Lander shape (local coords, angle 0 = pointing up, Y+ is down in world)
local BODY = {
    {-8, -8}, {-4, -12}, {4, -12}, {8, -8},
    {10, 0}, {8, 6}, {-8, 6}, {-10, 0},
}

local LEGS = {
    {{-8, 6}, {-14, 16}},
    {{-6, 6}, {-14, 16}},
    {{8, 6}, {14, 16}},
    {{6, 6}, {14, 16}},
}

local FEET = {
    {{-17, 16}, {-11, 16}},
    {{11, 16}, {17, 16}},
}

local WINDOW = {
    {{-3, -6}, {3, -6}},
    {{3, -6}, {3, -2}},
    {{3, -2}, {-3, -2}},
    {{-3, -2}, {-3, -6}},
}

local ANTENNA = {
    {{0, -12}, {0, -18}},
    {{-3, -18}, {3, -18}},
}

local lander = {}

function Lander.init()
    lander.x = World.WORLD_W / 2 + (math.random() - 0.5) * 800
    lander.y = 200
    lander.vx = 5 + math.random() * 8     -- gentle initial drift
    lander.vy = 2 + math.random() * 3     -- slight downward
    lander.angle = 0
    lander.alive = true
    lander.landed = false
    lander.thrusting = false
end

function Lander.get()
    return lander
end

local function transformPoint(px, py, angle, cx, cy)
    local cos_a = math.cos(angle)
    local sin_a = math.sin(angle)
    return cx + px * cos_a - py * sin_a,
           cy + px * sin_a + py * cos_a
end

function Lander.update(dt)
    if not lander.alive or lander.landed then return end

    -- Gravity (always pulls down)
    lander.vy = lander.vy + GRAVITY * dt

    -- Rotation
    if love.keyboard.isDown("left", "a") then
        lander.angle = lander.angle - ROT_SPEED * dt
    end
    if love.keyboard.isDown("right", "d") then
        lander.angle = lander.angle + ROT_SPEED * dt
    end

    -- Thrust (fires out the bottom of the lander, pushing opposite)
    lander.thrusting = love.keyboard.isDown("up", "w") and World.fuel > 0
    if lander.thrusting then
        lander.vx = lander.vx + math.sin(lander.angle) * THRUST_ACCEL * dt
        lander.vy = lander.vy - math.cos(lander.angle) * THRUST_ACCEL * dt
        World.fuel = math.max(0, World.fuel - FUEL_RATE * dt)
    end

    -- Cap speed so it doesn't get out of control
    local speed = math.sqrt(lander.vx * lander.vx + lander.vy * lander.vy)
    if speed > MAX_SPEED then
        lander.vx = lander.vx / speed * MAX_SPEED
        lander.vy = lander.vy / speed * MAX_SPEED
    end

    -- Move
    lander.x = lander.x + lander.vx * dt
    lander.y = lander.y + lander.vy * dt

    -- Clamp X to world bounds
    lander.x = math.max(20, math.min(World.WORLD_W - 20, lander.x))

    -- Don't let lander fly off the top
    if lander.y < 0 then
        lander.y = 0
        lander.vy = math.max(0, lander.vy)
    end
end

function Lander.abort()
    if not lander.alive or lander.landed then return end
    if World.fuel < 10 then return end

    -- Auto-level: snap angle to upright
    lander.angle = lander.angle * 0.1
    -- Strong upward thrust burst — halve downward velocity and push up
    if lander.vy > 0 then
        lander.vy = lander.vy * 0.3
    end
    lander.vy = lander.vy - THRUST_ACCEL * 0.6
    -- Kill most horizontal speed
    lander.vx = lander.vx * 0.3
    -- Heavy fuel cost
    World.fuel = math.max(0, World.fuel - 60)
end

function Lander.getCollisionPoints()
    local pts = {}
    local footPts = {{-17, 16}, {-11, 16}, {11, 16}, {17, 16}}
    for _, fp in ipairs(footPts) do
        local wx, wy = transformPoint(fp[1], fp[2], lander.angle, lander.x, lander.y)
        table.insert(pts, {x = wx, y = wy})
    end
    local bodyBottom = {{-8, 6}, {8, 6}, {0, 6}}
    for _, bp in ipairs(bodyBottom) do
        local wx, wy = transformPoint(bp[1], bp[2], lander.angle, lander.x, lander.y)
        table.insert(pts, {x = wx, y = wy})
    end
    return pts
end

function Lander.die()
    lander.alive = false
end

function Lander.land()
    lander.landed = true
    lander.vx = 0
    lander.vy = 0
end

function Lander.draw()
    if not lander.alive then return end

    local p = Palette.get()
    local a = lander.angle
    local cx, cy = lander.x, lander.y

    -- Body outline
    love.graphics.setColor(p.lander)
    love.graphics.setLineWidth(2)
    local bodyPts = {}
    for _, v in ipairs(BODY) do
        local wx, wy = transformPoint(v[1], v[2], a, cx, cy)
        table.insert(bodyPts, wx)
        table.insert(bodyPts, wy)
    end
    table.insert(bodyPts, bodyPts[1])
    table.insert(bodyPts, bodyPts[2])
    love.graphics.line(bodyPts)

    -- Legs
    love.graphics.setLineWidth(1.5)
    for _, leg in ipairs(LEGS) do
        local x1, y1 = transformPoint(leg[1][1], leg[1][2], a, cx, cy)
        local x2, y2 = transformPoint(leg[2][1], leg[2][2], a, cx, cy)
        love.graphics.line(x1, y1, x2, y2)
    end

    -- Feet
    love.graphics.setLineWidth(2)
    for _, foot in ipairs(FEET) do
        local x1, y1 = transformPoint(foot[1][1], foot[1][2], a, cx, cy)
        local x2, y2 = transformPoint(foot[2][1], foot[2][2], a, cx, cy)
        love.graphics.line(x1, y1, x2, y2)
    end

    -- Window
    love.graphics.setColor(p.lander[1], p.lander[2], p.lander[3], 0.5)
    love.graphics.setLineWidth(1)
    for _, seg in ipairs(WINDOW) do
        local x1, y1 = transformPoint(seg[1][1], seg[1][2], a, cx, cy)
        local x2, y2 = transformPoint(seg[2][1], seg[2][2], a, cx, cy)
        love.graphics.line(x1, y1, x2, y2)
    end

    -- Antenna
    love.graphics.setColor(p.lander)
    for _, seg in ipairs(ANTENNA) do
        local x1, y1 = transformPoint(seg[1][1], seg[1][2], a, cx, cy)
        local x2, y2 = transformPoint(seg[2][1], seg[2][2], a, cx, cy)
        love.graphics.line(x1, y1, x2, y2)
    end

    -- Thrust flame (fully transformed)
    if lander.thrusting then
        love.graphics.setColor(p.thrust)
        love.graphics.setLineWidth(2)
        local flameLen = 10 + math.random() * 15
        local flameSpread = 3 + math.random() * 3

        local fx1, fy1 = transformPoint(-flameSpread, 8, a, cx, cy)
        local fx2, fy2 = transformPoint(flameSpread, 8, a, cx, cy)
        local ftx, fty = transformPoint((math.random()-0.5)*3, 8 + flameLen, a, cx, cy)

        love.graphics.line(fx1, fy1, ftx, fty)
        love.graphics.line(fx2, fy2, ftx, fty)

        -- Inner bright flame
        love.graphics.setColor(p.bright)
        local flameLen2 = 5 + math.random() * 8
        local fi1x, fi1y = transformPoint(-1.5, 8, a, cx, cy)
        local fi2x, fi2y = transformPoint(1.5, 8, a, cx, cy)
        local ft2x, ft2y = transformPoint((math.random()-0.5)*1.5, 8 + flameLen2, a, cx, cy)
        love.graphics.line(fi1x, fi1y, ft2x, ft2y)
        love.graphics.line(fi2x, fi2y, ft2x, ft2y)
    end
end

return Lander