#!/bin/bash
set -e

# ============================================================================
# PRD Skill Installer
#
# Usage:
#   From a clone:   ./install.sh
#   From GitHub:    curl -fsSL https://raw.githubusercontent.com/codesoda/make-prd/main/install.sh | bash
# ============================================================================

# Colors for output
RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[1;33m'
CYAN='\033[0;36m'
NC='\033[0m' # No Color

SKILL_NAME="prd"
REPO_URL="https://github.com/codesoda/make-prd.git"
CLONE_DIR="$HOME/.local/share/make-prd"

# ============================================================================
# Functions
# ============================================================================

print_header() {
    echo -e "${CYAN}"
    echo "  ____  ____  ____    ____  _    _ _ _ "
    echo " |  _ \\|  _ \\|  _ \\  / ___|| | _(_) | |"
    echo " | |_) | |_) | | | | \\___ \\| |/ / | | |"
    echo " |  __/|  _ <| |_| |  ___) |   <| | | |"
    echo " |_|   |_| \\_\\____/  |____/|_|\\_\\_|_|_|"
    echo -e "${NC}"
    echo "PRD Generator Skill for Claude Code & Codex"
    echo "============================================"
    echo ""
}

print_section() {
    local title="$1"
    echo ""
    echo -e "${CYAN}━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━${NC}"
    echo -e "${YELLOW}${title}${NC}"
    echo -e "${CYAN}━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━${NC}"
    echo ""
}

resolve_source_dir() {
    # If running from a clone (BASH_SOURCE is set and points to a real file),
    # use that directory. Otherwise, clone from GitHub.
    if [ -n "${BASH_SOURCE[0]:-}" ] && [ -f "${BASH_SOURCE[0]}" ]; then
        SOURCE_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
        echo -e "Installing from local clone: ${CYAN}$SOURCE_DIR${NC}"
    else
        print_section "Downloading from GitHub"
        if [ -d "$CLONE_DIR/.git" ]; then
            echo "Updating existing clone..."
            git -C "$CLONE_DIR" pull --ff-only
        else
            echo "Cloning repository..."
            git clone "$REPO_URL" "$CLONE_DIR"
        fi
        SOURCE_DIR="$CLONE_DIR"
        echo -e "${GREEN}Downloaded to $SOURCE_DIR${NC}"
    fi
}

detect_install_location() {
    print_section "Detecting Installation Location"

    local HAS_CLAUDE=false
    local HAS_CODEX=false

    if command -v claude &> /dev/null; then
        HAS_CLAUDE=true
    fi
    if command -v codex &> /dev/null; then
        HAS_CODEX=true
    fi

    if ! $HAS_CLAUDE && ! $HAS_CODEX; then
        echo -e "${RED}Error: Neither Claude Code nor Codex CLI found.${NC}"
        echo -e "${RED}Install at least one before running this installer.${NC}"
        exit 1
    fi

    INSTALL_DIR=""
    if $HAS_CLAUDE; then
        INSTALL_DIR="$HOME/.claude/skills"
        mkdir -p "$INSTALL_DIR"
        echo -e "${GREEN}Claude Code detected${NC} — installing to $INSTALL_DIR"
    fi

    CODEX_INSTALL_DIR=""
    if $HAS_CODEX; then
        CODEX_INSTALL_DIR="$HOME/.codex/skills"
        mkdir -p "$CODEX_INSTALL_DIR"
        echo -e "${GREEN}Codex detected${NC} — installing to $CODEX_INSTALL_DIR"
    fi

    echo ""
}

install_skill_to_dir() {
    local dir="$1"
    local label="$2"

    echo -e "${YELLOW}${label}:${NC}"
    echo ""

    local TARGET="$dir/$SKILL_NAME"

    if [ -e "$TARGET" ] || [ -L "$TARGET" ]; then
        rm -rf "$TARGET"
        echo -e "  Replacing existing $SKILL_NAME skill..."
    fi
    ln -s "$SOURCE_DIR" "$TARGET"
    echo -e "${GREEN}  + $SKILL_NAME${NC}"
    echo ""
}

install_skill() {
    print_section "Installing PRD Skill"

    echo "Creating skill symlink..."
    echo ""

    if [ -n "$INSTALL_DIR" ]; then
        install_skill_to_dir "$INSTALL_DIR" "Claude Code ($INSTALL_DIR)"
    fi

    if [ -n "$CODEX_INSTALL_DIR" ]; then
        install_skill_to_dir "$CODEX_INSTALL_DIR" "Codex ($CODEX_INSTALL_DIR)"
    fi
}

show_usage() {
    print_section "Getting Started"

    echo "The PRD skill is now installed! Use it like this:"
    echo ""
    echo -e "${CYAN}Create a PRD:${NC}"
    echo "  /prd build a task priority system"
    echo ""
    echo -e "${CYAN}Or describe what you want:${NC}"
    echo "  /prd add user authentication with OAuth"
    echo ""
    echo -e "${CYAN}To update later:${NC}"
    echo "  Re-run this installer to pull the latest version."
    echo ""
}

# ============================================================================
# Main Installation Flow
# ============================================================================

main() {
    print_header
    resolve_source_dir
    detect_install_location
    install_skill
    show_usage

    print_section "Installation Complete"
    echo -e "${GREEN}PRD skill is ready to use!${NC}"
    echo ""
}

main