I know nothing about Turkish politics.
Can someone give a brief explanation of the major parties, issues, demographics etc?
Justice and Development Party (AKP) - started as a moderate splinter of the Welfare Party, an Islamist party that briefly held power in the 90s before being banned under pressure from the military. Originally they presented themselves as the Muslim equivalent of Christian democratic parties in Europe. Lately though, they have been becoming increasingly authoritarian and conservative. In terms of economics, they are fairly statist, having undertaken many public works projects. Their base is the rural poor although they have a significant amount of support in Istanbul as well, where President Ergodan was mayor. Comparable parties: Somewhere between Merkel's CDU and United Russia.
Republican People's Party (CHP) - traces its history back to the party founded by Mustafa Kemal Ataturk. The party's main ideology is Kemalism, which means secularism, respect for the military's role in politics, and a form of nationalism that rejects ethnicity (ie Kurdish desire to break away) Today the party is also nominally social democratic but that means less in Turkey even than it does in Europe. However, under the current leader, there has been some attempt to change that, to make it a more generic social democratic party and to drop the support for the military and (even less successfully so far) the opposition to Kurdish nationalism. Its main base of support is the big cities of Istanbul and Ankara and along the coasts, as well as around military bases and universities. Comparable parties: Maybe PASOK.
Nationalist Action Party, alternatively translated as Nationalist Movement Party (MHP) - Started as the political wing of the Grey Wolves, a right-wing paramilitary active during the 70s which carried out several terrorist attacks back and forth against Communist groups. They were likely funded by the military and eventually the military stepped in to solve the fighting by having a coup and banning all political activity in 1980. The Grey Wolves were also likely funded by NATO as a contingency plan against a possible Communist take over of Turkey. With Communism no longer an issue, the party is primarily focused on opposing peace with the Kurds, pissing off Armenia, and the fantastical plans to merge with Azerbajian and Turkmenistan. Also, just in the last campaign, it embraced a sort of soft Islamism, after years of being secular to ambivalent. I have no idea what demographic this party attracts. No one seems to know. Presumably right-wingers who don't like Erdogan for whatever reason. Comparable parties: The Serbian Radical Party or one of those Slovak nationalist parties that propped up the social democratic government there.
People's Democratic Party (HDP) - Just like Islamist parties, Turkey has a long history of banning Kurdish parties which only come back and reform under a new name right after being banned. The latest is the People's Democratic Party. It's a little bit different in that it has made a legitimately attempt to appeal to non-Kurds. It has the most left-wing platform, both economically and socially, of any major party. Not only does it have quotas for the number of women candidates it fields, it even has a quota for gay candidates. Its main base is Kurdish areas (obviously) but it also does well in hipster parts of Istanbul. Comparable parties: SYRIZA, PODEMOS.
No other party came close to passing the insanely high 10% threshold in the last election but a couple of other historically significant parties are the Democratic Party (conservative party who were either moderate Kemalists or moderate Islamists who feign Kemalism), the Democratic Left Party (more explicitly social democrat, less pro-military splinter from the Republican People's Party), and the Felicity Party (representing the more hardcore wing of the banned Welfare Party).
