use super::*;
use types::address::{PhysicalAddress, VirtualAddress};
use types::id::{ProcessId, RegionId};
use types::mapping::PagePerms;

const BASE: usize = 0x8400_0000;

fn table() -> FrameTable<8> {
    FrameTable::new(PhysicalAddress::from_raw(BASE), 8)
}

fn pid(n: u16) -> ProcessId {
    ProcessId::from_raw(n)
}

fn va(addr: usize) -> VirtualAddress {
    VirtualAddress::from_raw(addr)
}

fn user(owner: u16, addr: usize) -> FrameUse {
    FrameUse::user(pid(owner), va(addr), PagePerms::ReadWrite).unwrap()
}

#[test]
fn new_table_has_every_frame_free() {
    let t = table();
    assert_eq!(t.free_count(), 8);
    assert_eq!(t.capacity(), 8);
}

#[test]
fn total_is_clamped_to_capacity() {
    let t: FrameTable<4> = FrameTable::new(PhysicalAddress::from_raw(BASE), 100);
    assert_eq!(t.free_count(), 4);
}

#[test]
fn user_use_requires_page_aligned_va() {
    assert!(FrameUse::user(pid(0), va(0x1234), PagePerms::ReadOnly).is_none());
    assert!(FrameUse::user(pid(0), va(0x1000), PagePerms::ReadOnly).is_some());
}

#[test]
fn alloc_hands_out_distinct_frames_inside_the_pool() {
    let mut t = table();
    let a = t.alloc(user(0, 0x1000)).unwrap();
    let b = t.alloc(user(0, 0x2000)).unwrap();
    assert_ne!(a, b);
    for pa in [a, b] {
        assert!(pa.raw() >= BASE && pa.raw() < BASE + 8 * 4096);
        assert_eq!(pa.raw() % 4096, 0);
    }
    assert_eq!(t.free_count(), 6);
}

#[test]
fn alloc_fails_when_exhausted() {
    let mut t = table();
    for i in 0..8 {
        t.alloc(user(0, (i + 1) * 0x1000)).unwrap();
    }
    assert!(t.alloc(user(0, 0x9000)).is_none());
}

#[test]
fn free_returns_the_frame_and_its_use() {
    let mut t = table();
    let pa = t.alloc(user(3, 0x5000)).unwrap();
    assert_eq!(t.free(pa), Some(user(3, 0x5000)));
    assert_eq!(t.free_count(), 8);
}

#[test]
fn freeing_a_free_frame_is_rejected() {
    let mut t = table();
    let pa = t.alloc(user(0, 0x1000)).unwrap();
    t.free(pa).unwrap();
    assert_eq!(t.free(pa), None);
    assert_eq!(t.free_count(), 8);
}

#[test]
fn freeing_outside_the_pool_or_unaligned_is_rejected() {
    let mut t = table();
    t.alloc(user(0, 0x1000)).unwrap();
    assert_eq!(t.free(PhysicalAddress::from_raw(BASE - 4096)), None);
    assert_eq!(t.free(PhysicalAddress::from_raw(BASE + 8 * 4096)), None);
    assert_eq!(t.free(PhysicalAddress::from_raw(BASE + 1)), None);
    assert_eq!(t.free_count(), 7);
}

#[test]
fn find_user_matches_owner_and_va() {
    let mut t = table();
    let pa = t.alloc(user(1, 0x3000)).unwrap();
    assert_eq!(
        t.find_user(pid(1), va(0x3000)),
        Some((pa, PagePerms::ReadWrite))
    );
    assert_eq!(t.find_user(pid(2), va(0x3000)), None);
    assert_eq!(t.find_user(pid(1), va(0x4000)), None);
}

#[test]
fn retag_moves_a_frame_to_a_new_use() {
    let mut t = table();
    let pa = t.alloc(user(1, 0x3000)).unwrap();
    assert!(t.retag(pa, user(2, 0x7000)));
    assert_eq!(t.find_user(pid(1), va(0x3000)), None);
    assert_eq!(t.find_user(pid(2), va(0x7000)).map(|(p, _)| p), Some(pa));
}

#[test]
fn retag_of_a_free_frame_is_rejected() {
    let mut t = table();
    let pa = t.alloc(user(1, 0x3000)).unwrap();
    t.free(pa);
    assert!(!t.retag(pa, user(2, 0x7000)));
    assert_eq!(t.free_count(), 8);
}

#[test]
fn alloc_contiguous_returns_adjacent_frames() {
    let mut t = table();
    let base = t
        .alloc_contiguous(3, |_| FrameUse::Region {
            region: RegionId::from_raw(0),
        })
        .unwrap();
    assert_eq!(t.free_count(), 5);
    for i in 0..3 {
        assert_eq!(
            t.get(base.offset(i)),
            Some(&FrameUse::Region {
                region: RegionId::from_raw(0)
            })
        );
    }
}

#[test]
fn alloc_contiguous_fails_without_a_long_enough_run() {
    let mut t: FrameTable<4> = FrameTable::new(PhysicalAddress::from_raw(BASE), 4);
    let a = t.alloc(user(0, 0x1000)).unwrap();
    let _b = t.alloc(user(0, 0x2000)).unwrap();
    let _c = t.alloc(user(0, 0x3000)).unwrap();
    t.free(a);
    // free frames: 0 and 3 — no run of 2
    assert!(
        t.alloc_contiguous(2, |_| FrameUse::PageTable { owner: pid(0) })
            .is_none()
    );
    assert_eq!(t.free_count(), 2);
}

#[test]
fn free_owned_by_releases_only_that_processes_frames() {
    let mut t = table();
    t.alloc(user(1, 0x1000)).unwrap();
    t.alloc(FrameUse::PageTable { owner: pid(1) }).unwrap();
    let other = t.alloc(user(2, 0x1000)).unwrap();
    let region = t
        .alloc(FrameUse::Region {
            region: RegionId::from_raw(1),
        })
        .unwrap();

    assert_eq!(t.free_owned_by(pid(1)), 2);
    assert_eq!(t.free_count(), 6);
    assert!(t.get(other).is_some());
    assert!(t.get(region).is_some());
}

#[test]
fn user_frames_of_lists_mappings_of_one_process() {
    let mut t = table();
    t.alloc(user(1, 0x1000)).unwrap();
    t.alloc(user(2, 0x2000)).unwrap();
    t.alloc(user(1, 0x3000)).unwrap();
    t.alloc(FrameUse::PageTable { owner: pid(1) }).unwrap();
    let mut vas = [0usize; 4];
    let mut n = 0;
    for (_, v) in t.user_frames_of(pid(1)) {
        vas[n] = v.raw();
        n += 1;
    }
    assert_eq!(&vas[..n], &[0x1000, 0x3000]);
}