let colors = {};
let rasterized = {};

// https://stackoverflow.com/a/17243070
function hsv_to_rgb(h, s, v) {
    let r, g, b;

    const i = Math.floor(h * 6);
    const f = h * 6 - i;
    const p = v * (1 - s);
    const q = v * (1 - f * s);
    const t = v * (1 - (1 - f) * s);

    switch (i % 6) {
        case 0: r = v, g = t, b = p; break;
        case 1: r = q, g = v, b = p; break;
        case 2: r = p, g = v, b = t; break;
        case 3: r = p, g = q, b = v; break;
        case 4: r = t, g = p, b = v; break;
        case 5: r = v, g = p, b = q; break;
    }

    return [
        Math.round(r * 255),
        Math.round(g * 255),
        Math.round(b * 255)
    ];
}
function get_color(stage_name) {
    if (stage_name in config.predefined_colors) {
        return config.predefined_colors[stage_name];
    }

    if (stage_name in colors) {
        return colors[stage_name];
    }

    colors[stage_name] = hsv_to_rgb(Math.random(), 0.56, 0.56); 

    return colors[stage_name];
}

function rasterize_and_pack(text, cycles) {
    // TODO: handle texture is full or stuff don't fit (unlikely)

    const key = text;

    if (key in rasterized) {
        return rasterized[key];
    }

    const u = raster_tile.x * config.w / config.raster_texture_size;
    const v = raster_tile.y * config.h / config.raster_texture_size;

    rasterize(text);    
    gl.bindTexture(gl.TEXTURE_2D, textures['raster']);
    gl.texSubImage2D(gl.TEXTURE_2D, 0, 
        raster_tile.x * config.w, raster_tile.y * config.h, 
        config.w, config.h, 
        gl.RGBA, gl.UNSIGNED_BYTE, 
        c2d.canvas
    );

    raster_tile.x += 1;
    if (raster_tile.x === config.raster_texture_size / config.w) {
        raster_tile.x = 0;
        raster_tile.y += 1;
    }

    rasterized[key] = [u, v];

    if (cycles > 1) {
        gl.bindTexture(gl.TEXTURE_2D, textures['numbers']);
        for (let i = numbers_rasterized + 1; i <= cycles; ++i) {
            const u = number_tile.x * config.w / config.raster_texture_size;
            const v = number_tile.y * config.h / config.raster_texture_size;

            rasterize(i);            

            gl.texSubImage2D(gl.TEXTURE_2D, 0, 
                number_tile.x * config.w, number_tile.y * config.h, 
                config.w, config.h, 
                gl.RGBA, gl.UNSIGNED_BYTE, 
                c2d.canvas
            );

            number_tile.x += 1;
            if (number_tile.x === config.raster_texture_size / config.w) {
                number_tile.x = 0;
                number_tile.y += 1;
            }

            rasterized[i] = [u, v];
        }

        if (cycles > numbers_rasterized) {
            numbers_rasterized = cycles;
        }
    }

    return [u, v];
}

function pack_instruction(instruction, positions, sizes, colors, uvs, starts, y) {
    starts.push(positions.length);
    
    for (let i = 0; i < instruction.lanes['0'].length; ++i) {
        const stage = instruction.lanes['0'][i];
        let stage_cycles;

        if (i < instruction.lanes['0'].length - 1) {
            const next_stage = instruction.lanes['0'][i + 1];
            stage_cycles = next_stage.c - stage.c;
        } else {
            stage_cycles = instruction.retcyc - stage.c;
        }

        let [r, g, b] = get_color(stage.name);
        let a = 255;

        if (!instruction.retired) {
            a = 80;
        }

        const [u, v] = rasterize_and_pack(stage.name, stage_cycles);

        sizes.push(stage_cycles * config.w + (stage_cycles - 1) * config.padding, 1 * config.h);
        positions.push(config.w * stage.c + config.padding * (stage.c - 1), config.h * y + config.padding * (y - 1)); 
        colors.push(r, g, b, a);
        uvs.push(u, v);
    }

    return instruction.lanes['0'].length;
}

function generate(trace_id) {
    const before = performance.now();

    const result = {
        'count': 0,
    };

    const positions = [];
    const sizes = [];
    const colors = [];
    const uvs = [];
    const starts = [];

    let instructions = {};

    if (trace_id in traces) {
        instructions = traces[trace_id].raw;
    }

    let y = 0;

    for (let i = 0; i < instructions.length; ++i) {
        const instruction = instructions[i];
        // TODO: make all quads same size, abuse this fact 
        result.count += pack_instruction(instruction, positions, sizes, colors, uvs, starts, y);
        if (config.limit > 0 && result.count >= config.limit) {
            break;
        }
        ++y;
    }

    starts.push(positions.length);

    if (config.show_texture) {
        result.pos = new Float32Array([0, 0]);
        result.size = new Float32Array([config.raster_texture_size, config.raster_texture_size]);
        result.color = new Uint8Array([0, 0, 0, 255]);
        result.uv = new Float32Array([0, 0]);
        result.count = 1;
        result.trace_id = trace_id;
        result.uploaded = false;
    } else {
        result.pos = new Float32Array(positions);
        result.size = new Float32Array(sizes);
        result.color = new Uint8Array(colors);
        result.uv = new Float32Array(uvs);
        result.trace_id = trace_id;
        result.uploaded = false;
        result.start = new Int32Array(starts);
    }

    const after = performance.now();

    console.log(`Generated geometry in ${Math.round(after - before)}ms`);

    return result;
}

function clip(quads) {
    if (config.show_texture) {
        return quads;
    }

    const tl = screen_to_canvas({'x': 0, 'y': 0});
    const br = screen_to_canvas({'x': 0, 'y': canvas.height});

    const x1 = tl.x;
    const y1 = tl.y;

    const x2 = br.x;
    const y2 = br.y;

    const result = {
        'count': 0,
    };

    if (quads.count === 0) {
        return result;
    }

    let i0 = -1;
    let i1 = -1;

    for (let i = 0; i < quads.start.length - 1; ++i) {
        const index = quads.start[i];
        const next = quads.start[i + 1];

        const left = quads.pos[index];
        const top = quads.pos[index + 1];
        const bottom = top + quads.size[index + 1];
        const right = quads.pos[next - 2] + quads.size[next - 2];

        if (bottom < y1) {
            if (i < quads.start.length / 2 - 2) {
                const index_ahead = quads.start[i * 2];
                const top_ahead = quads.pos[index_ahead + 1];
                const bottom_ahead = top_ahead + quads.size[index_ahead + 1];

                if (bottom_ahead < y1) {
                    i *= 2;
                    continue;
                }
            }
        }

        if (bottom < y1 || right < x1) {
            continue;
        }

        if (top > y2) {
            i1 = quads.start[i + 1];
            break;
        }

        if (i0 === -1) {
            i0 = index;
        }
    }

    result.pos = quads.pos.subarray(i0, i1);
    result.size = quads.size.subarray(i0, i1);
    result.color = quads.color.subarray(i0 * 2, i1 * 2);
    result.uv = quads.uv.subarray(i0, i1);
    result.count = (i1 - i0) / 2;
    result.uploaded = false;

    return result;
}