Minecraft Flamethrower with Only One Command

summon falling_block ~ ~1 ~ {Block:stone,Time:1,Passengers:[{id:falling_block,Block:redstone_block,Time:1,Passengers:[{id:falling_block,Block:activator_rail,Time:1,Passengers:[{id:commandblock_minecart,Command:"gamerule commandBlockOutput false"},{id:commandblock_minecart,Command:"fill ~2 ~-3 ~3 ~-2 ~-1 ~9 concrete 1 hollow"},{id:commandblock_minecart,Command:"fill ~2 ~-2 ~3 ~-2 ~-2 ~9 stained_glass 14 0 concrete"},{id:commandblock_minecart,Command:"/scoreboard objectives add itemih dummy"},{id:commandblock_minecart,Command:"/scoreboard objectives add flame dummy"},{id:commandblock_minecart,Command:" /give @p minecraft:fishing_rod 1 0 {display:{Name:\"Flamethrower\",Lore:[\"by The Creative Simon\"]}}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:"/tellraw @a [\"\",{\"text\":\"Check out my \"},{\"text\":\"YT-Channel \",\"color\":\"dark_red\"},{\"text\":\"right -> \",\"color\":\"none\"},{\"text\":\"HERE\",\"color\":\"green\",\"bold\":true,\"underlined\":true,\"clickEvent\":{\"action\":\"open_url\",\"value\":\"https://www.YouTube.com/TheCreativeSimon\"}}]"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:" /tellraw @a {\"text\":\"\"}"},{id:commandblock_minecart,Command:"setblock ~ ~-3 ~2 wall_sign 2 0 {Text1:\"{\\\"text\\\":\\\"============\\\"}\",Text2:\"{\\\"text\\\":\\\"Click to destroy\\\"}\",Text3:\"{\\\"text\\\":\\\"this machine\\\"}\",Text4:\"{\\\"text\\\":\\\"============\\\",\\\"clickEvent\\\":{\\\"action\\\":\\\"run_command\\\",\\\"value\\\":\\\"fill ~-3 ~ ~ ~2 ~2 ~7 air\\\"}}\"}"},{id:commandblock_minecart,Command:"setblock ~ ~-2 ~2 wall_sign 2 0 {Text1:\"{\\\"text\\\":\\\"\\\"}\",Text2:\"{\\\"text\\\":\\\"Flamethrower\\\",\\\"color\\\":\\\"dark_blue\\\",\\\"italic\\\":true}\",Text3:\"{\\\"text\\\":\\\"by TCSimon\\\",\\\"color\\\":\\\"dark_red\\\"}\",Text4:\"{\\\"text\\\":\\\"\\\"}\"}"},{id:commandblock_minecart,Command:"fill ~-1 ~-2 ~4 ~1 ~-2 ~8 chain_command_block 3"},{id:commandblock_minecart,Command:"setblock ~ ~-2 ~4 chain_command_block 4"},{id:commandblock_minecart,Command:"fill ~ ~-2 ~8 ~ ~-2 ~5 chain_command_block 2"},{id:commandblock_minecart,Command:"setblock ~1 ~-2 ~8 chain_command_block 4"},{id:commandblock_minecart,Command:"setblock ~1 ~-2 ~4 repeating_command_block 3"},{id:commandblock_minecart,Command:"blockdata ~-1 ~-2 ~7 {auto:1,Command:\"/execute @e[name=unknown,score_flame_min=3] ~ ~ ~ setblock ~ ~ ~ fire 0 replace air\"}"},{id:commandblock_minecart,Command:"blockdata ~-1 ~-2 ~6 {auto:1,Command:\"/execute @e[name=unknown,score_flame_min=3] ~ ~ ~ effect @e[r=1] instant_damage 1 1\"}"},{id:commandblock_minecart,Command:"blockdata ~-1 ~-2 ~5 {auto:1,Command:\"/execute @e[name=unknown,score_flame_min=3] ~ ~ ~ particle flame ~ ~ ~ 0.5 0 0.5 0 50 normal\"}"},{id:commandblock_minecart,Command:"blockdata ~-1 ~-2 ~4 {auto:1,Command:\"/execute @a[score_itemih_min=2] ~ ~ ~ scoreboard players add @e[name=unknown,r=5] flame 1\"}"},{id:commandblock_minecart,Command:"blockdata ~ ~-2 ~4 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:8,Inventory:[{Slot:8b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~ ~-2 ~5 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:7,Inventory:[{Slot:7b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~ ~-2 ~6 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:6,Inventory:[{Slot:6b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~ ~-2 ~7 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:5,Inventory:[{Slot:5b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~ ~-2 ~8 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:4,Inventory:[{Slot:4b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~1 ~-2 ~8 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:3,Inventory:[{Slot:3b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~1 ~-2 ~7 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:2,Inventory:[{Slot:2b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~1 ~-2 ~6 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:1,Inventory:[{Slot:1b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~1 ~-2 ~5 {auto:1,Command:\"/scoreboard players set @a itemih 2 {SelectedItemSlot:0,Inventory:[{Slot:0b,tag:{display:{Name:\\\"Flamethrower\\\"}}}]}\"}"},{id:commandblock_minecart,Command:"blockdata ~1 ~-2 ~4 {auto:1,Command:\"/scoreboard players set @a itemih 1\"}"},{id:commandblock_minecart,Command:"setblock ~ ~ ~1 command_block 0 0 {Command:\"fill ~ ~-3 ~-1 ~ ~ ~ air\"}"},{id:commandblock_minecart,Command:"setblock ~ ~-1 ~1 redstone_block"},{id:commandblock_minecart,Command:"kill @e[type=commandblock_minecart,r=1]"}]}]}]}