#!/bin/bash

# Semantic commit pattern - fixed to properly handle hyphens in scope
# Moved the hyphen to the end of the character class to avoid interpretation issues
PATTERN='^(feat|fix|docs|style|refactor|test|perf|build|ci|chore|revert)(\([a-zA-Z0-9\._-]+\))?: .{1,}$'

# Pattern for merge commits from pull requests - simplified to catch all formats
PR_MERGE_PATTERN='^Merge pull request'

# Pattern for standard Git merge commits
GIT_MERGE_PATTERN='^Merge (branch|remote-tracking branch) .+ into .+$'

# Set text colors
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
BLUE='\033[0;34m'
MAGENTA='\033[0;35m'
CYAN='\033[0;36m'
BOLD='\033[1m'
NC='\033[0m' # No Color

# Statistics tracking
INVALID_COMMITS=0
VALID_COMMITS=0
MERGE_COMMITS=0
TOTAL_COMMITS=0

# Track commit types for summary
declare -A COMMIT_TYPES=(
    ["feat"]=0 ["fix"]=0 ["docs"]=0 ["style"]=0 ["refactor"]=0
    ["test"]=0 ["perf"]=0 ["build"]=0 ["ci"]=0 ["chore"]=0 ["revert"]=0
)

# Track authors
declare -A AUTHORS=()

# Track files changed
TOTAL_FILES_CHANGED=0
TOTAL_INSERTIONS=0
TOTAL_DELETIONS=0

# Function to draw a horizontal bar
draw_bar() {
    local value=$1
    local max=$2
    local width=30
    local bar_width=$((value * width / max))

    # Ensure minimum width of 1 if value > 0
    if [ "$value" -gt 0 ] && [ "$bar_width" -eq 0 ]; then
        bar_width=1
    fi

    printf "[%${bar_width}s%$((width - bar_width))s] %d\n" | tr ' ' '#' | tr ' ' '.'
}

# Function to extract commit type
get_commit_type() {
    local subject="$1"
    echo "$subject" | grep -oP '^(feat|fix|docs|style|refactor|test|perf|build|ci|chore|revert)' || echo "unknown"
}

# ASCII box drawing for commit stats
draw_box() {
    local title="$1"
    local width=60
    local padding=$(((width - ${#title}) / 2))

    echo -e "${BOLD}┌$(printf '─%.0s' $(seq 1 $width))┐${NC}"
    echo -e "${BOLD}│$(printf ' %.0s' $(seq 1 $padding))$title$(printf ' %.0s' $(seq 1 $((width - padding - ${#title}))))│${NC}"
    echo -e "${BOLD}└$(printf '─%.0s' $(seq 1 $width))┘${NC}"
}

# Read stdin (format: <old-value> <new-value> <ref-name>)
while read -r OLD_REV NEW_REV REF_NAME; do
    # Skip if it's a branch deletion
    if [[ "$NEW_REV" = "0000000000000000000000000000000000000000" ]]; then
        continue
    fi

    # Skip if it's a new branch (no old revision)
    if [[ "$OLD_REV" = "0000000000000000000000000000000000000000" ]]; then
        OLD_REV=$(git rev-list --max-parents=0 "$NEW_REV")
    fi

    echo -e "${YELLOW}Checking commits in $REF_NAME${NC}"

    # Get branch stats from git
    BRANCH_COMMITS=$(git rev-list --count "$REF_NAME")
    BRANCH_AGE=$(git log -1 --format="%cr" "$REF_NAME")

    echo -e "${CYAN}→ Branch has $BRANCH_COMMITS total commits (created $BRANCH_AGE)${NC}"
    echo ""

    # Get all commit hashes between old and new revision
    COMMITS=$(git rev-list "$OLD_REV".."$NEW_REV")

    # Check each commit message
    for COMMIT in $COMMITS; do
        TOTAL_COMMITS=$((TOTAL_COMMITS + 1))
        COMMIT_MSG=$(git log --format=%B -n 1 "$COMMIT")
        COMMIT_SUBJECT=$(echo "$COMMIT_MSG" | head -n 1)
        PARENT_COUNT=$(git rev-list --parents -n 1 "$COMMIT" | awk '{print NF - 1}')
        AUTHOR=$(git log -1 --format="%an" "$COMMIT")
        COMMIT_DATE=$(git log -1 --format="%cd" --date=relative "$COMMIT")
        SHORT_HASH=${COMMIT:0:8}

        # Get commit stats
        STATS=$(git show --stat --format="" "$COMMIT")
        FILES_CHANGED=$(echo "$STATS" | grep -c "^[ ]*")
        INSERTIONS=$(echo "$STATS" | grep -o '[0-9]* insertion' | cut -d' ' -f1 | awk '{sum+=$1} END {print sum+0}')
        DELETIONS=$(echo "$STATS" | grep -o '[0-9]* deletion' | cut -d' ' -f1 | awk '{sum+=$1} END {print sum+0}')

        # Update stats
        TOTAL_FILES_CHANGED=$((TOTAL_FILES_CHANGED + FILES_CHANGED))
        TOTAL_INSERTIONS=$((TOTAL_INSERTIONS + INSERTIONS))
        TOTAL_DELETIONS=$((TOTAL_DELETIONS + DELETIONS))

        # Update author stats
        if [[ -n "${AUTHORS[$AUTHOR]}" ]]; then
            AUTHORS[$AUTHOR]=$((AUTHORS[$AUTHOR] + 1))
        else
            AUTHORS[$AUTHOR]=1
        fi

        echo -e "${MAGENTA}Commit #$TOTAL_COMMITS:${NC} ${BOLD}$SHORT_HASH${NC} (by $AUTHOR, $COMMIT_DATE)"
        echo -e "  Changed: ${CYAN}$FILES_CHANGED files${NC} ${GREEN}+$INSERTIONS${NC}/${RED}-$DELETIONS${NC} lines"
        echo "  $COMMIT_SUBJECT"

        # Skip validation for merge commits (both PR merges and standard Git merges)
        if [[ $PARENT_COUNT -gt 1 ]] && ([[ "$COMMIT_SUBJECT" =~ $PR_MERGE_PATTERN ]] || [[ "$COMMIT_SUBJECT" =~ $GIT_MERGE_PATTERN ]]); then
            echo -e "  ${BLUE}➜ Skipping merge commit validation${NC}"
            MERGE_COMMITS=$((MERGE_COMMITS + 1))
            continue
        fi

        if ! [[ "$COMMIT_SUBJECT" =~ $PATTERN ]]; then
            echo -e "  ${RED}✗ Invalid commit message${NC}"
            echo -e "  ${YELLOW}  Should follow pattern:${NC} type(scope): message"
            INVALID_COMMITS=$((INVALID_COMMITS + 1))
        else
            echo -e "  ${GREEN}✓ Valid semantic commit${NC}"
            VALID_COMMITS=$((VALID_COMMITS + 1))

            # Count commit type
            COMMIT_TYPE=$(get_commit_type "$COMMIT_SUBJECT")
            if [[ -n "${COMMIT_TYPES[$COMMIT_TYPE]}" ]]; then
                COMMIT_TYPES[$COMMIT_TYPE]=$((COMMIT_TYPES[$COMMIT_TYPE] + 1))
            fi
        fi

        echo ""
    done

    # Add push summary
    draw_box "COMMIT STATISTICS"
    echo -e "${BOLD}Total commits in this push:${NC} $TOTAL_COMMITS"
    echo -e "${GREEN}Valid semantic commits:   ${NC} $VALID_COMMITS"
    echo -e "${BLUE}Merge commits:           ${NC} $MERGE_COMMITS"
    echo -e "${RED}Invalid commits:         ${NC} $INVALID_COMMITS"
    echo ""

    if [ $TOTAL_COMMITS -gt 0 ]; then
        VALID_PERCENT=$(((VALID_COMMITS + MERGE_COMMITS) * 100 / TOTAL_COMMITS))
        echo -e "${BOLD}Semantic compliance:${NC} $VALID_PERCENT%"

        # Print bar
        printf "["
        for ((i = 0; i < VALID_PERCENT / 5; i++)); do
            printf "${GREEN}#${NC}"
        done
        for ((i = VALID_PERCENT / 5; i < 20; i++)); do
            printf "${RED}.${NC}"
        done
        printf "] $VALID_PERCENT%%\n"
        echo ""
    fi

    # Commit type distribution if we have valid commits
    if [ $VALID_COMMITS -gt 0 ]; then
        draw_box "COMMIT TYPE DISTRIBUTION"
        for type in "${!COMMIT_TYPES[@]}"; do
            count=${COMMIT_TYPES[$type]}
            if [ $count -gt 0 ]; then
                # Calculate percentage
                percent=$((count * 100 / VALID_COMMITS))
                printf "%-10s " "$type:"
                draw_bar $count $VALID_COMMITS
                echo " $count ($percent%)"
            fi
        done
        echo ""
    fi

    # Author distribution
    if [ ${#AUTHORS[@]} -gt 0 ]; then
        draw_box "AUTHOR DISTRIBUTION"
        for author in "${!AUTHORS[@]}"; do
            count=${AUTHORS[$author]}
            percent=$((count * 100 / TOTAL_COMMITS))
            printf "%-20s " "$author:"
            draw_bar $count $TOTAL_COMMITS
            echo " $count ($percent%)"
        done
        echo ""
    fi

    # File stats
    draw_box "CHANGE STATISTICS"
    echo -e "Files changed:   $TOTAL_FILES_CHANGED"
    echo -e "Lines added:     ${GREEN}+$TOTAL_INSERTIONS${NC}"
    echo -e "Lines removed:   ${RED}-$TOTAL_DELETIONS${NC}"
    echo -e "Net change:      $((TOTAL_INSERTIONS - TOTAL_DELETIONS)) lines"
    echo ""
done

# If any commits were invalid, reject the push
if [[ $INVALID_COMMITS -gt 0 ]]; then
    echo -e "${RED}Push rejected: $INVALID_COMMITS commit(s) have invalid messages.${NC}"
    echo -e "${YELLOW}Please rewrite your commit messages to follow the semantic commit format:${NC}"
    echo "type(scope): message"
    echo -e "\nExamples:"
    echo "  feat(auth): add login with Google"
    echo "  fix: correct calculation in billing module"
    echo "  style(release.yml): format permissions section in YAML"
    exit 1
fi

exit 0