#!/usr/bin/env bash
set -euo pipefail
IFS=$'\n\t'

#######################################
# Security Check
#######################################
security_variable=2  # Allowed values: 0, 1, or 2

if [ "$security_variable" -eq 0 ]; then
    echo "Error: security_variable is set to 0. Exiting the script."
    exit 1
fi

if [ "$security_variable" -eq 2 ]; then
    echo "security_variable is set to 2. Running the script without further checks."
else
    # When security_variable==1, only run on Friday.
    DAY_OF_WEEK=$(date +%A)
    if [ "$DAY_OF_WEEK" = "Friday" ]; then
        echo "Today is Friday. Continuing with the script."
    else
        echo "Today is not Friday (Today is $DAY_OF_WEEK). Exiting the script."
        exit 0
    fi
fi

#######################################
# Dependency Checks
#######################################
for cmd in git nmcli msmtp ssh scp gh timeout; do
    if ! command -v "$cmd" &>/dev/null; then
        echo "$cmd is required but not installed. Exiting."
        exit 1
    fi
done

#######################################
# Configuration
#######################################
TXT_FILE="/home/klein/.config/setup/autogitupdate.txt"
CREDENTIALS_FILE="$HOME/.config/setup/credentials.config"
REPORT="/tmp/git_update_report.txt"     # Full detailed report
SMS_REPORT="/tmp/git_update_sms.txt"      # Minimal SMS summary
SMS_CHAR_LIMIT=160                        # Character limit for SMS messages
SSH_DIR="/home/klein/reports"
BRANCH_NAME="main"                        # Default branch name

if [ ! -f "$TXT_FILE" ]; then
    echo "Error: Configuration file '$TXT_FILE' not found. Exiting the script."
    exit 1
fi

if [ ! -f "$CREDENTIALS_FILE" ]; then
    echo "Error: Credentials file '$CREDENTIALS_FILE' not found. Exiting the script."
    exit 1
fi

# Source the credentials.
source "$CREDENTIALS_FILE"

# Ensure required credentials are set.
if [ -z "${EMAIL:-}" ] || [ -z "${SSH_HOST:-}" ] || [ -z "${PHONE_NUMBER:-}" ]; then
    echo "Error: Missing required credentials (EMAIL, SSH_HOST, or PHONE_NUMBER) in '$CREDENTIALS_FILE'. Exiting."
    exit 1
fi

# Ensure report files exist and have strict permissions.
ensure_file() {
    local file="$1"
    local permissions="$2"
    [ ! -f "$file" ] && touch "$file" && chmod "$permissions" "$file"
    chmod "$permissions" "$file"
}

ensure_file "$REPORT" 600
ensure_file "$SMS_REPORT" 600

#######################################
# Helper Functions
#######################################

# Check WiFi connection and Internet availability.
check_wifi() {
    nmcli -t -f ACTIVE,SSID dev wifi | grep -q "^yes" && ping -c 1 8.8.8.8 &>/dev/null
    return $?
}

# Read the repository directories from TXT_FILE.
get_repo_dirs() {
    local valid_dirs=()
    while IFS= read -r repo_dir; do
        # Trim whitespace and skip empty lines or comment lines.
        repo_dir=$(echo "$repo_dir" | xargs)
        if [[ -z "$repo_dir" || "$repo_dir" == \#* ]]; then
            continue
        fi
        # Only add directories that exist and contain a .git folder.
        if [ -d "$repo_dir" ] && [ -d "$repo_dir/.git" ]; then
            valid_dirs+=("$repo_dir")
        fi
    done < "$TXT_FILE"
    # Output each valid repository on its own line.
    printf "%s\n" "${valid_dirs[@]}"
}

# Create a GitHub repository from a local repository.
create_github_repo() {
    local repo_name="$1"
    local repo_dir="$2"
    local repo_number="$3"
    echo "Attempting to create GitHub repo for repo $repo_number ($repo_name)" >> "$REPORT"
    
    # The GH command uses the absolute path as source.
    if gh repo create "$repo_name" --public --source="$repo_dir" --remote=origin --push; then
        echo "Successfully created GitHub repository #$repo_number: $repo_name" >> "$REPORT"
        echo "Repo #$repo_number $repo_name: GHS" >> "$SMS_REPORT"
        echo "Success GHS"
    else
        echo "Failed to create GitHub repository #$repo_number: $repo_name" >> "$REPORT"
        echo "Repo #$repo_number: GCF" >> "$SMS_REPORT"
        echo "GCF Repo"
        return 1
    fi
    return 0
}

# Check if a remote GitHub origin exists.
check_github_remote() {
    if ! remote_url=$(git remote get-url origin 2>/dev/null); then
        echo "No 'origin' remote found." >> "$REPORT"
        return 1
    fi

    echo "Debug: Found remote URL: $remote_url" >> "$REPORT"
    
    if [[ "$remote_url" != *github.com* ]]; then
        echo "'origin' remote does not point to GitHub." >> "$REPORT"
        return 1
    fi
    
    local repo_name repo_owner full_repo_name
    repo_name=$(basename "$remote_url" .git)
    repo_owner=$(basename "$(dirname "$remote_url")")
    full_repo_name="$repo_owner/$repo_name"
    
    echo "Checking if GitHub repository '$full_repo_name' exists..." >> "$REPORT"
    if ! gh repo view "$full_repo_name" &>/dev/null; then
        echo "GitHub repository '$full_repo_name' does not exist or is not accessible." >> "$REPORT"
        return 1
    fi
    
    return 0
}

# Check if the repository is up-to-date.
is_repo_up_to_date() {
    git remote update &>/dev/null
    if git status -uno | grep -q "Your branch is up to date"; then
        echo "Repository is up to date. No fetch needed."
        return 0
    else
        echo "Repository is not up to date. Fetching changes..."
        return 1
    fi
}

# Verify that the repository’s .git folder is valid.
# (This function does not treat an empty repository as an error.)
is_valid_git_repo() {
    local repo_dir="$1"
    
    if [ ! -d "$repo_dir/.git" ]; then
        echo "Error: '.git' directory is missing in '$repo_dir'. Skipping this repository." >> "$REPORT"
        return 1
    fi

    for file in HEAD config; do
        if [ ! -f "$repo_dir/.git/$file" ]; then
            echo "Error: Missing '$file' in '.git' directory of '$repo_dir'. Skipping this repository." >> "$REPORT"
            return 1
        fi
    done

    # Do not fail here if no commits exist; we'll handle it later.
    return 0
}

# Logging function to write timestamped messages.
log_msg() {
    local msg="$1"
    echo "$(date '+%Y-%m-%d %H:%M:%S') - $msg" >> "$REPORT"
}

#######################################
# Core Update Function
#######################################
update_repo() {
    local repo_dir="$1"
    local repo_number="$2"

    cd "$repo_dir" || { log_msg "Repo #$repo_number: Could not change directory to $repo_dir"; return 1; }
    log_msg "Processing repository #$repo_number at $repo_dir"

    # Validate the repository structure.
    if ! is_valid_git_repo "$repo_dir"; then
        log_msg "Repo #$repo_number: Invalid repository structure. Skipping."
        echo "Invalid .git" >> "$SMS_REPORT"
        return 1
    fi

    # If no commit exists, create an initial empty commit.
    if ! git rev-parse HEAD &>/dev/null; then
        log_msg "Repo #$repo_number: No commits found. Creating an initial empty commit."
        if ! git commit --allow-empty -m "Initial commit"; then
            log_msg "Repo #$repo_number: Failed to create an initial commit."
            echo "Repo #$repo_number: No commit" >> "$SMS_REPORT"
            return 1
        fi
    fi

    # Check for detached HEAD state.
    local current_branch
    current_branch=$(git rev-parse --abbrev-ref HEAD)
    if [ "$current_branch" == "HEAD" ]; then
        log_msg "Repo #$repo_number: Detached HEAD state. Skipping repository."
        echo "Repo #$repo_number: Detached HEAD" >> "$SMS_REPORT"
        return 1
    fi

    # Check for a valid GitHub remote.
    local remote_available=true
    if ! check_github_remote; then
        log_msg "Repo #$repo_number: No valid GitHub remote found."
        remote_available=false
        if check_wifi; then
            local repo_name
            repo_name=$(basename "$repo_dir")
            create_github_repo "$repo_name" "$repo_dir" "$repo_number"
            # Recheck the remote.
            if check_github_remote; then
                remote_available=true
            else
                log_msg "Repo #$repo_number: Failed to create remote repository."
            fi
        else
            log_msg "Repo #$repo_number: No WiFi. Will commit locally only."
        fi
    fi

    # Check if there are any local changes.
    if [ -z "$(git status --porcelain)" ]; then
        log_msg "Repo #$repo_number: No local changes detected."
        if [ "$remote_available" = false ]; then
            echo "Repo #$repo_number: NC-GDE" >> "$SMS_REPORT"
        else
            echo "Repo #$repo_number: NC-GE" >> "$SMS_REPORT"
        fi
        return 0
    fi

    # Stage all changes.
    git add -A

    # Commit changes (overriding PGP signing requirement for automation).
    if git -c commit.gpgSign=false commit -m "Automated update"; then
        log_msg "Repo #$repo_number: Local commit succeeded."
    else
        log_msg "Repo #$repo_number: Commit failed (perhaps nothing to commit)."
        echo "Repo #$repo_number: No commit" >> "$SMS_REPORT"
        return 0
    fi

    # If a remote exists and WiFi is available, attempt a pull with rebase.
    if [ "$remote_available" = true ] && check_wifi; then
        log_msg "Repo #$repo_number: Attempting pull --rebase on branch '$current_branch'."
        if timeout 60s git pull --rebase --no-edit origin "$current_branch"; then
            log_msg "Repo #$repo_number: Rebase succeeded."
        else
            log_msg "Repo #$repo_number: Rebase failed; aborting and attempting merge fallback."
            git rebase --abort || log_msg "Repo #$repo_number: Failed to abort rebase cleanly."
            if timeout 60s git pull --no-edit origin "$current_branch"; then
                log_msg "Repo #$repo_number: Merge fallback succeeded."
            else
                log_msg "Repo #$repo_number: Merge fallback failed. Manual intervention required."
                echo "Repo #$repo_number: Rebase/Merge Conflict" >> "$SMS_REPORT"
                return 1
            fi
        fi
    else
        log_msg "Repo #$repo_number: Skipping pull/rebase (no remote or no internet)."
    fi

    # Push changes if remote is available and internet is active.
    if [ "$remote_available" = true ] && check_wifi; then
        log_msg "Repo #$repo_number: Attempting push on branch '$current_branch'."
        if timeout 60s git push origin "$current_branch"; then
            log_msg "Repo #$repo_number: Push succeeded."
            echo "Repo #$repo_number: P" >> "$SMS_REPORT"
        else
            log_msg "Repo #$repo_number: Push timed out or failed."
            echo "Repo #$repo_number: PF" >> "$SMS_REPORT"
            return 1
        fi
    else
        log_msg "Repo #$repo_number: No internet; changes committed locally."
        echo "Repo #$repo_number: LC" >> "$SMS_REPORT"
    fi
}

#######################################
# Main Script Execution
#######################################
echo "Starting auto git update script on $(date)" > "$REPORT"
echo "(G-R), $(date)" > "$SMS_REPORT"

# Read valid repository directories into an array.
mapfile -t repo_dirs < <(get_repo_dirs)

# Initialize counters for SMS summary.
pushed_count=0
no_change_count=0
local_commit_count=0
conflict_count=0
error_count=0
created_count=0
no_github_repo_count=0
total_repos=${#repo_dirs[@]}

repo_number=1
for repo_dir in "${repo_dirs[@]}"; do
    echo "Updating repository #$repo_number: $repo_dir"
    update_repo "$repo_dir" "$repo_number"
    case "$(tail -n 1 "$SMS_REPORT")" in
        *P) pushed_count=$((pushed_count + 1)) ;;
        *NC*) no_change_count=$((no_change_count + 1)) ;;
        *LC) local_commit_count=$((local_commit_count + 1)) ;;
        *MC) conflict_count=$((conflict_count + 1)) ;;
        *PF) error_count=$((error_count + 1)) ;;
        *lc-ngr*) no_github_repo_count=$((no_github_repo_count + 1)) ;;
        *GHS) created_count=$((created_count + 1)) ;;
    esac
    repo_number=$((repo_number + 1))
done

# If the SMS report exceeds the character limit, generate a concise summary.
sms_detailed_content=$(cat "$SMS_REPORT")
if [ "${#sms_detailed_content}" -gt "$SMS_CHAR_LIMIT" ]; then
    DATE=$(date "+%Y-%m-%d %H:%M:%S")
    sms_summary="$DATE. Pushed: $pushed_count/$total_repos, No Change: $no_change_count/$total_repos, Locally Committed: $local_commit_count/$total_repos, Conflicts: $conflict_count/$total_repos, Errors: $error_count/$total_repos, No GitHub Repo: $no_github_repo_count/$total_repos, Created: $created_count/$total_repos"
    echo "$sms_summary" > "$SMS_REPORT"
fi

# Function to send an SMS/text notification.
send_text() {
    /usr/bin/msmtp -a default -t <<EOF
To: $PHONE_NUMBER
From: $EMAIL
Subject: Git Update Report

$(cat "$SMS_REPORT")
EOF
    return $?
}

# Function to copy the detailed report to a remote host via SSH.
copy_report_ssh() {
    if [ -z "$SSH_DIR" ]; then
        echo "Error: SSH_DIR is not set. Please define it in your script."
        return 1
    fi
    ssh "$SSH_HOST" "mkdir -p $SSH_DIR"
    rsync -avz --progress "$REPORT" "$SSH_HOST:$SSH_DIR/"
    return $?
}

if check_wifi; then
    echo "WiFi is connected. Attempting to send text message and perform SSH transfer..."
    send_text && echo "Text message sent successfully." || echo "Failed to send text message."
    if copy_report_ssh; then
        echo "SSH transfer succeeded."
        rm -f "$REPORT"
    else
        echo "SSH transfer failed. Keeping local reports for troubleshooting."
    fi
else
    echo "No WiFi connection detected. Changes committed locally."
fi