#!/bin/bash
# =============================================================================
# 🔧 StianNOR-ZSHkit — .zshrc Merge Script
# Merges managed sections from ZSHkit/.zshrc into the live ~/.zshrc
# without overwriting personal aliases or custom configuration.
#
# How it works:
#   - Managed sections in ~/.zshrc are wrapped with markers:
#       # --- ZSHKIT:section_name ---
#       ... content ...
#       # --- /ZSHKIT:section_name ---
#   - On first run, markers are injected into your existing ~/.zshrc
#   - On subsequent runs, content between markers is updated from ZSHkit
#   - Everything outside the markers is never touched
#
# Usage:
#   ./update_zshrc.sh           — merge and apply
#   ./update_zshrc.sh --dry-run — show what would change, no writes
#   ./update_zshrc.sh --status  — show which sections are present
# =============================================================================
set -euo pipefail

GREEN='\033[0;32m'; YELLOW='\033[1;33m'; CYAN='\033[0;36m'
RED='\033[0;31m'; BOLD='\033[1m'; RESET='\033[0m'
LINE="────────────────────────────────────────────────────────────────────────────"

info()    { echo -e "${CYAN}ℹ  $*${RESET}"; }
success() { echo -e "${GREEN}✅ $*${RESET}"; }
warn()    { echo -e "${YELLOW}⚠  $*${RESET}"; }
error()   { echo -e "${RED}❌ $*${RESET}"; }

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
SOURCE="$SCRIPT_DIR/.zshrc"
TARGET="$HOME/.zshrc"
BACKUP="$HOME/.zshrc.bak.$(date +%Y%m%d-%H%M%S)"
DRY_RUN=false
STATUS_ONLY=false

case "${1:-}" in
    --dry-run) DRY_RUN=true ;;
    --status)  STATUS_ONLY=true ;;
esac

if [[ ! -f "$SOURCE" ]]; then
    error "Source not found: $SOURCE"
    exit 1
fi

if [[ ! -f "$TARGET" ]]; then
    warn "No ~/.zshrc found — copying source directly"
    cp "$SOURCE" "$TARGET"
    success "Created $TARGET from ZSHkit source"
    exit 0
fi

declare -A SECTION_START=(
    [autosuggestions]="# ─── Autosuggestions"
    [aliases]="# ─── User Aliases and Functions"
)
declare -A SECTION_END=(
    [autosuggestions]="source \$ZSH/oh-my-zsh.sh"
    [aliases]="alias rsy="
)

# =============================================================================
# STATUS MODE
# =============================================================================
if [[ "$STATUS_ONLY" = true ]]; then
    echo -e "\n${BOLD}${CYAN}🔧 .zshrc Managed Sections Status${RESET}"
    echo -e "${LINE}"
    for section in "${!SECTION_START[@]}"; do
        marker="# --- ZSHKIT:${section} ---"
        if grep -qF "$marker" "$TARGET" 2>/dev/null; then
            success "Section present: $section"
        else
            warn "Section missing (will be injected on next run): $section"
        fi
    done
    echo -e "${LINE}\n"
    exit 0
fi

# =============================================================================
# BACKUP
# =============================================================================
cp "$TARGET" "$BACKUP"
info "Backup saved: $BACKUP"

echo -e "\n${BOLD}${CYAN}🔧 Merging .zshrc sections${RESET}"
echo -e "${LINE}"

CHANGED=0

merge_section() {
    local name="$1"
    local start_pat="$2"
    local end_pat="$3"

    local begin_marker="# --- ZSHKIT:${name} ---"
    local end_marker="# --- /ZSHKIT:${name} ---"

    local new_content
    new_content=$(awk "/$start_pat/{found=1} found{print} /$end_pat/{if(found) {found=0}}" "$SOURCE")

    if [[ -z "$new_content" ]]; then
        warn "Could not extract section '$name' from source — skipping"
        return
    fi

    local block
    block="$begin_marker
$new_content
$end_marker"

    if grep -qF "$begin_marker" "$TARGET"; then
        local existing
        existing=$(awk "/$begin_marker/{found=1; next} /$end_marker/{found=0; next} found{print}" "$TARGET")
        if [[ "$existing" == "$new_content" ]]; then
            success "Up to date: $name"
            return
        fi
        if [[ "$DRY_RUN" = true ]]; then
            warn "[DRY RUN] Would update section: $name"
            diff <(echo "$existing") <(echo "$new_content") || true
        else
            python3 - "$TARGET" "$begin_marker" "$end_marker" "$new_content" <<'PYEOF'
import sys, re
target   = sys.argv[1]
begin    = sys.argv[2]
end      = sys.argv[3]
new_body = sys.argv[4]
with open(target, 'r') as f:
    content = f.read()
pattern = re.escape(begin) + r'.*?' + re.escape(end)
replacement = begin + '\n' + new_body + '\n' + end
new_content = re.sub(pattern, replacement, content, flags=re.DOTALL)
with open(target, 'w') as f:
    f.write(new_content)
PYEOF
            success "Updated section: $name"
            (( CHANGED++ )) || true
        fi
    else
        if [[ "$DRY_RUN" = true ]]; then
            warn "[DRY RUN] Would inject new section: $name"
        else
            if grep -q "# End of .zshrc" "$TARGET"; then
                python3 - "$TARGET" "# End of .zshrc" "$block" <<'PYEOF'
import sys
target    = sys.argv[1]
marker    = sys.argv[2]
new_block = sys.argv[3]
with open(target, 'r') as f:
    content = f.read()
content = content.replace(marker, new_block + '\n\n' + marker)
with open(target, 'w') as f:
    f.write(content)
PYEOF
            else
                echo "" >> "$TARGET"
                echo "$block" >> "$TARGET"
            fi
            success "Injected new section: $name"
            (( CHANGED++ )) || true
        fi
    fi
}

merge_section "autosuggestions" \
    "# ─── Autosuggestions" \
    "source \\\$ZSH/oh-my-zsh.sh"

merge_section "aliases" \
    "# ─── User Aliases and Functions" \
    "alias rsy="

echo -e "${LINE}"
if [[ "$DRY_RUN" = true ]]; then
    warn "Dry run complete — no files were modified"
elif [[ $CHANGED -eq 0 ]]; then
    success "Everything already up to date — no changes needed"
else
    success "$CHANGED section(s) updated in $TARGET"
    echo -e "\n  ${YELLOW}Run ${CYAN}fresh${RESET}${YELLOW} or open a new terminal to apply changes.${RESET}"
fi
echo -e "${LINE}\n"