// Copyright 2016 by Sascha L. Teichmann
// Use of this source code is governed by the MIT license
// that can be found in the LICENSE file.

package common

import (
	"math/rand"
	"testing"
)

func randomBaseTileHash(updates int) *BaseTileHash {
	bth := NewBaseTileHash(256)
	h1 := []byte{1}
	h2 := []byte{2}
	for i := 0; i < updates; i++ {
		x, y := rand.Intn(100), rand.Intn(100)
		var h []byte
		if i%2 == 0 {
			h = h1
		} else {
			h = h2
		}
		bth.Update(x, y, h)
	}
	return bth
}

func TestBaseTileHash(t *testing.T) {
	for _, updates := range []int{10, 100, 1000, 10000} {
		bth := randomBaseTileHash(updates)
		entries := map[*btHashEntry]bool{}

		for cur := bth.root.next; cur != &bth.root; cur = cur.next {
			if entries[cur] {
				t.Errorf("hash element found more than once: %d", updates)
			}
			entries[cur] = true
		}
		if len(entries) != len(bth.hashes) {
			t.Errorf("List has differnt length than hashes: %d : %d",
				len(entries), len(bth.hashes))
		}
		var already1 bool
		var already2 bool
		for k, v := range bth.hashes {
			if !entries[v] {
				if !already1 {
					already1 = true
					t.Errorf("Hash contains pointer to element not being in list: %d",
						updates)
				}
			}
			if k != v.btKey {
				if !already2 {
					already2 = true
					t.Errorf("Key in entry does not match hash key: %d", updates)
				}
			}
			delete(entries, v)
		}

		if len(entries) > 0 {
			t.Error("There a are more entries than indexed by hash")
		}
	}
}

func TestBaseTileHashOverwrite(t *testing.T) {
	bth := NewBaseTileHash(256)
	h1 := []byte{1}
	h2 := []byte{2}

	if updated := bth.Update(0, 0, h1); !updated {
		t.Error("First insert does not trigger update")
	}

	if updated := bth.Update(0, 0, h2); !updated {
		t.Error("Second insert does not trigger update")
	}

	if updated := bth.Update(0, 0, h2); updated {
		t.Error("Third insert does trigger update")
	}
}

func TestBaseTileHashSeparate(t *testing.T) {
	bth := NewBaseTileHash(256)
	h1 := []byte{1}

	if updated := bth.Update(0, 0, h1); !updated {
		t.Error("First insert does not trigger update")
	}

	if updated := bth.Update(0, 1, h1); !updated {
		t.Error("Second insert does not trigger update")
	}

	if updated := bth.Update(1, 0, h1); !updated {
		t.Error("Third insert does trigger update")
	}

	if len(bth.hashes) != 3 {
		t.Errorf("Expected size to be 3. Current size: %d", len(bth.hashes))
	}
}

func TestBaseTileHashLRU(t *testing.T) {
	bth := NewBaseTileHash(2)
	h1 := []byte{1}

	if updated := bth.Update(0, 0, h1); !updated {
		t.Error("First insert does not trigger update")
	}

	if updated := bth.Update(0, 1, h1); !updated {
		t.Error("Second insert does not trigger update")
	}

	if updated := bth.Update(1, 0, h1); !updated {
		t.Error("Third insert does trigger update")
	}

	if len(bth.hashes) != 2 {
		t.Errorf("Expected size to be 2. Current size: %d", len(bth.hashes))
	}
}