#!/bin/sh

test_description='split commit graph'
. ./test-lib.sh

GIT_TEST_COMMIT_GRAPH=0

test_expect_success 'setup repo' '
        git init &&
        git config core.commitGraph true &&
        infodir=".git/objects/info" &&
        graphdir="$infodir/commit-graphs" &&
        test_oid_init
'

graph_read_expect() {
        NUM_BASE=0
        if test ! -z $2
        then
                NUM_BASE=$2
        fi
        cat >expect <<- EOF
        header: 43475048 1 1 3 $NUM_BASE
        num_commits: $1
        chunks: oid_fanout oid_lookup commit_metadata
        EOF
        git commit-graph read >output &&
        test_cmp expect output
}

test_expect_success 'create commits and write commit-graph' '
        for i in $(test_seq 3)
        do
                test_commit $i &&
                git branch commits/$i || return 1
        done &&
        git commit-graph write --reachable &&
        test_path_is_file $infodir/commit-graph &&
        graph_read_expect 3
'

graph_git_two_modes() {
        git -c core.commitGraph=true $1 >output
        git -c core.commitGraph=false $1 >expect
        test_cmp expect output
}

graph_git_behavior() {
        MSG=$1
        BRANCH=$2
        COMPARE=$3
        test_expect_success "check normal git operations: $MSG" '
                graph_git_two_modes "log --oneline $BRANCH" &&
                graph_git_two_modes "log --topo-order $BRANCH" &&
                graph_git_two_modes "log --graph $COMPARE..$BRANCH" &&
                graph_git_two_modes "branch -vv" &&
                graph_git_two_modes "merge-base -a $BRANCH $COMPARE"
        '
}

graph_git_behavior 'graph exists' commits/3 commits/1

verify_chain_files_exist() {
        for hash in $(cat $1/commit-graph-chain)
        do
                test_path_is_file $1/graph-$hash.graph || return 1
        done
}

test_expect_success 'add more commits, and write a new base graph' '
        git reset --hard commits/1 &&
        for i in $(test_seq 4 5)
        do
                test_commit $i &&
                git branch commits/$i || return 1
        done &&
        git reset --hard commits/2 &&
        for i in $(test_seq 6 10)
        do
                test_commit $i &&
                git branch commits/$i || return 1
        done &&
        git reset --hard commits/2 &&
        git merge commits/4 &&
        git branch merge/1 &&
        git reset --hard commits/4 &&
        git merge commits/6 &&
        git branch merge/2 &&
        git commit-graph write --reachable &&
        graph_read_expect 12
'

test_expect_success 'fork and fail to base a chain on a commit-graph file' '
        test_when_finished rm -rf fork &&
        git clone . fork &&
        (
                cd fork &&
                rm .git/objects/info/commit-graph &&
                echo "$(pwd)/../.git/objects" >.git/objects/info/alternates &&
                test_commit new-commit &&
                git commit-graph write --reachable --split &&
                test_path_is_file $graphdir/commit-graph-chain &&
                test_line_count = 1 $graphdir/commit-graph-chain &&
                verify_chain_files_exist $graphdir
        )
'

test_expect_success 'add three more commits, write a tip graph' '
        git reset --hard commits/3 &&
        git merge merge/1 &&
        git merge commits/5 &&
        git merge merge/2 &&
        git branch merge/3 &&
        git commit-graph write --reachable --split &&
        test_path_is_missing $infodir/commit-graph &&
        test_path_is_file $graphdir/commit-graph-chain &&
        ls $graphdir/graph-*.graph >graph-files &&
        test_line_count = 2 graph-files &&
        verify_chain_files_exist $graphdir
'

graph_git_behavior 'split commit-graph: merge 3 vs 2' merge/3 merge/2

test_expect_success 'add one commit, write a tip graph' '
        test_commit 11 &&
        git branch commits/11 &&
        git commit-graph write --reachable --split &&
        test_path_is_missing $infodir/commit-graph &&
        test_path_is_file $graphdir/commit-graph-chain &&
        ls $graphdir/graph-*.graph >graph-files &&
        test_line_count = 3 graph-files &&
        verify_chain_files_exist $graphdir
'

graph_git_behavior 'three-layer commit-graph: commit 11 vs 6' commits/11 commits/6

test_expect_success 'add one commit, write a merged graph' '
        test_commit 12 &&
        git branch commits/12 &&
        git commit-graph write --reachable --split &&
        test_path_is_file $graphdir/commit-graph-chain &&
        test_line_count = 2 $graphdir/commit-graph-chain &&
        ls $graphdir/graph-*.graph >graph-files &&
        test_line_count = 2 graph-files &&
        verify_chain_files_exist $graphdir
'

graph_git_behavior 'merged commit-graph: commit 12 vs 6' commits/12 commits/6

test_expect_success 'create fork and chain across alternate' '
        git clone . fork &&
        (
                cd fork &&
                git config core.commitGraph true &&
                rm -rf $graphdir &&
                echo "$(pwd)/../.git/objects" >.git/objects/info/alternates &&
                test_commit 13 &&
                git branch commits/13 &&
                git commit-graph write --reachable --split &&
                test_path_is_file $graphdir/commit-graph-chain &&
                test_line_count = 3 $graphdir/commit-graph-chain &&
                ls $graphdir/graph-*.graph >graph-files &&
                test_line_count = 1 graph-files &&
                git -c core.commitGraph=true  rev-list HEAD >expect &&
                git -c core.commitGraph=false rev-list HEAD >actual &&
                test_cmp expect actual
        )
'

graph_git_behavior 'alternate: commit 13 vs 6' commits/13 commits/6

test_done