----------------------------- ClimateStripes -----------------------------
-- climate stripes + line graph viewer for picotron
function _init()
    num_stripes = 176
    start_year = 1850

    -- 1. Define climate data (Global, from Met Office)
    anomalies = {
       -0.600, -0.438, -0.389, -0.421, -0.432, -0.427, -0.472, -0.618, -0.547, -0.434, -0.558, -0.634, -0.724, -0.578, -0.681, -0.592, -0.596, -0.601, -0.547, -0.480, -0.475, -0.524, -0.446, -0.451, -0.497, -0.503, -0.550, -0.210, -0.113, -0.421, -0.426, -0.338, -0.397, -0.439, -0.584, -0.567, -0.513, -0.603, -0.490, -0.374, -0.625, -0.534, -0.645, -0.630, -0.622, -0.581, -0.410, -0.393, -0.609, -0.475, -0.364, -0.420, -0.569, -0.658, -0.724, -0.525, -0.437, -0.618, -0.625, -0.644, -0.636, -0.650, -0.578, -0.573, -0.367, -0.308, -0.541, -0.673, -0.565, -0.469, -0.434, -0.359, -0.446, -0.420, -0.414, -0.387, -0.231, -0.329, -0.318, -0.498, -0.277, -0.211, -0.249, -0.424, -0.273, -0.305, -0.266, -0.110, -0.107, -0.136, -0.044, -0.172, -0.209, -0.197, -0.060, -0.158, -0.265, -0.231, -0.254, -0.268, -0.341, -0.164, -0.089, -0.022, -0.207, -0.289, -0.341, -0.102, -0.081, -0.112, -0.169, -0.065, -0.113, -0.084, -0.349, -0.254, -0.195, -0.160, -0.210, -0.068, -0.122, -0.242, -0.127, 0.014, -0.207, -0.143, -0.252, 0.063, -0.034, 0.059, 0.159, 0.216, -0.010, 0.185, 0.012, 0.013, 0.060, 0.207, 0.243, 0.140, 0.320, 0.298, 0.086, 0.123, 0.191, 0.338, 0.239, 0.383, 0.539, 0.285, 0.293, 0.450, 0.507, 0.505, 0.432, 0.571, 0.535, 0.554, 0.427, 0.559, 0.643, 0.502, 0.540, 0.583, 0.635, 0.784, 0.894, 0.804, 0.722, 0.854, 0.882, 0.732, 0.765, 1.073, 1.130, 1.009, 0.959
    }

	 -- 1.5. Set custom palette
	 local palette = {
	 	0x00000000,0x0008306b,0x0008519c,0x002171b5,0x004292c6,0x006baed6,0x009ecae1,0x00c6dbef,0x00deebf7,0x00fee0d2,0x00fcbba1,0x00fc9272,0x00fb6a4a,0x00ef3b2c,0x00cb181d,0x00a50f15,0x0067000d,0x00440007
	 }

	 for i = 1, #palette do
		poke4(0x5000 + 4 * (i-1),palette[i])		
	 end

    -- Interaction & View Toggle States
    mx, my, mb = 0, 0, 0
    was_clicked = false

    view_mode = 0     -- 0 = Stripes, 1 = Line Graph
    transition = 0.0   -- 0.0 (Stripes) to 1.0 (Line Graph)
end

function _update()
    mx, my, mb = mouse()

    -- Click detector toggle logic (avoids multi-firing)
    if mb == 1 then
        if not was_clicked then
            view_mode = 1 - view_mode -- Flip between 0 and 1
            was_clicked = true
        end
    else
        was_clicked = false
    end

    -- Interpolate smooth sliding transition
    transition += view_mode == 1 and 0.08 or -0.08
    transition = mid(0, transition, 1.0)
end

function _draw()
    cls()

    local w = 480
    local h = 270
    local stripe_w = w / num_stripes

    -- Graph plotting settings
    local graph_baseline = h / 2 - 10
    local graph_scale = 100

    -- Track highlighted index based on cursor x coordinate
    local selected_idx = flr(mx / stripe_w) + 1
    selected_idx = mid(1, selected_idx, num_stripes)

    -- Draw Data Structures
    for i=1, num_stripes do
        local norm = (anomalies[i] + 0.76) / 1.6
        local col_idx = flr(norm * 14) + 1

        local x1 = flr((i-1) * stripe_w)
        local x2 = flr(i * stripe_w)

        -- Interpolate structural shape layout changes
        -- Interpolates from full vertical height to thin line graph bars
        local target_y1 = flr(graph_baseline - (anomalies[i] * graph_scale))
        local target_y2 = graph_baseline
        if target_y1 > target_y2 then 
            target_y1, target_y2 = target_y2, target_y1 
        end

        local render_y1 = flr(0 * (1 - transition) + target_y1 * transition)
        local render_y2 = flr(240 * (1 - transition) + target_y2 * transition)

        rectfill(x1, render_y1, x2, render_y2, i==selected_idx and 13 or col_idx)
    end

    -- Draw Interactive Highlight Overlay UI

    -- Format values for layout display
    local sign = anomalies[selected_idx] >= 0 and "+" or ""
    local info_str = "YEAR:" .. start_year + (selected_idx - 1) 
     					.. "\tANOMALY: " .. sign .. anomalies[selected_idx]
     					.. "\31C\*d\t"

    -- Print data string in solid white text (Palette Entry 7)
    -- Mode hint text string info
    print(info_str .. (view_mode == 0 and "CLICK TO SHOW GRAPH" or "CLICK TO SHOW STRIPES"), 12, h - 18, 7)

end