#!/usr/bin/env bash
#
# release-engine.sh — Build, tag, and release the engine Docker images
#
# Usage:
#   ./release-engine.sh --gitea|--github [--dry-run] [--no-increment] [--patch|--minor|--major]

set -euo pipefail

#──────────────────────────────────────────────────────────────────────
# Config
#──────────────────────────────────────────────────────────────────────
SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
ENGINE_DIR="$SCRIPT_DIR/engine"
VERSION_FILE="$ENGINE_DIR/VERSION"

# Container registry
REGISTRY="${REGISTRY:-docker.dcglab.co.uk}"
IMAGE_ORG="${IMAGE_ORG:-dcg}"
IMAGE_BASE="${REGISTRY}/${IMAGE_ORG}/kb"

#──────────────────────────────────────────────────────────────────────
# Parse args
#──────────────────────────────────────────────────────────────────────
DRY_RUN=false
INCREMENT=true
BUMP="patch"
FORGE=""

for arg in "$@"; do
    case "$arg" in
        --dry-run)       DRY_RUN=true ;;
        --no-increment)  INCREMENT=false ;;
        --minor)         BUMP="minor" ;;
        --major)         BUMP="major" ;;
        --patch)         BUMP="patch" ;;
        --gitea)         FORGE="tea" ;;
        --github)        FORGE="gh" ;;
        *)
            echo "Unknown argument: $arg"
            echo "Usage: $0 --gitea|--github [--dry-run] [--no-increment] [--patch|--minor|--major]"
            exit 1
            ;;
    esac
done

if [[ -z "$FORGE" ]]; then
    echo "Error: specify --gitea or --github"
    echo "Usage: $0 --gitea|--github [--dry-run] [--no-increment] [--patch|--minor|--major]"
    exit 1
fi

# Ensure we're on main branch
CURRENT_BRANCH="$(git -C "$SCRIPT_DIR" rev-parse --abbrev-ref HEAD)"
if [[ "$CURRENT_BRANCH" != "main" ]]; then
    echo "Error: releases must be made from the main branch (currently on '$CURRENT_BRANCH')"
    exit 1
fi

if ! command -v "$FORGE" &>/dev/null; then
    echo "Error: '$FORGE' not found in PATH"
    exit 1
fi

#──────────────────────────────────────────────────────────────────────
# Version helpers
#──────────────────────────────────────────────────────────────────────
read_version() {
    local file="$1"
    if [[ ! -f "$file" ]]; then
        echo "Error: version file not found: $file" >&2
        exit 1
    fi
    tr -d '[:space:]' < "$file"
}

bump_version() {
    local ver="$1" part="$2"
    local major minor patch
    IFS='.' read -r major minor patch <<< "$ver"

    case "$part" in
        major) echo "$((major + 1)).0.0" ;;
        minor) echo "${major}.$((minor + 1)).0" ;;
        patch) echo "${major}.${minor}.$((patch + 1))" ;;
    esac
}

write_version() {
    local file="$1" ver="$2"
    echo "$ver" > "$file"
}

run() {
    echo "  $ $*"
    if [[ "$DRY_RUN" == false ]]; then
        "$@"
    fi
}

#──────────────────────────────────────────────────────────────────────
# Determine release version
#──────────────────────────────────────────────────────────────────────
CURRENT_VERSION="$(read_version "$VERSION_FILE")"

if [[ "$INCREMENT" == true ]]; then
    VERSION="$(bump_version "$CURRENT_VERSION" "$BUMP")"
    echo "==> Engine version bump: $CURRENT_VERSION → $VERSION ($BUMP)"
else
    VERSION="$CURRENT_VERSION"
    echo "==> Engine version: $VERSION (no increment)"
fi

GIT_TAG="engine-v${VERSION}"
DOCKER_TAG="v${VERSION}"

echo "    Git tag:   $GIT_TAG"
echo "    Image tag: $DOCKER_TAG"
echo "    Registry:  $IMAGE_BASE"
echo "    Forge CLI: $FORGE"
echo "    Dry run:   $DRY_RUN"
echo ""

#──────────────────────────────────────────────────────────────────────
# 1. Pre-flight checks
#──────────────────────────────────────────────────────────────────────
echo "==> Pre-flight checks"

if [[ "$DRY_RUN" == false ]]; then
    if git -C "$SCRIPT_DIR" rev-parse "$GIT_TAG" &>/dev/null; then
        echo "Error: tag $GIT_TAG already exists"
        exit 1
    fi
fi

echo "    OK"
echo ""

#──────────────────────────────────────────────────────────────────────
# 2. Update version file
#──────────────────────────────────────────────────────────────────────
if [[ "$INCREMENT" == true ]]; then
    echo "==> Updating engine version to $VERSION"
    run write_version "$VERSION_FILE" "$VERSION"
    echo ""
fi

#──────────────────────────────────────────────────────────────────────
# 3. Build Docker engine images
#──────────────────────────────────────────────────────────────────────
echo "==> Building Docker engine images ($VERSION)"

NVIDIA_IMAGE="${IMAGE_BASE}/engine:${DOCKER_TAG}-nvidia"
CPU_IMAGE="${IMAGE_BASE}/engine:${DOCKER_TAG}-cpu"
NVIDIA_LATEST="${IMAGE_BASE}/engine:latest-nvidia"
CPU_LATEST="${IMAGE_BASE}/engine:latest-cpu"

run docker build -t "$NVIDIA_IMAGE" -t "$NVIDIA_LATEST" -f "$ENGINE_DIR/Dockerfile.nvidia" "$ENGINE_DIR"
run docker build -t "$CPU_IMAGE" -t "$CPU_LATEST" -f "$ENGINE_DIR/Dockerfile.cpu" "$ENGINE_DIR"

echo ""

#──────────────────────────────────────────────────────────────────────
# 3b. Build Docker MCP server image
#──────────────────────────────────────────────────────────────────────
MCP_DIR="$SCRIPT_DIR/mcp"

if [[ -f "$MCP_DIR/Dockerfile" ]]; then
    echo "==> Building Docker MCP server image ($VERSION)"

    MCP_IMAGE="${IMAGE_BASE}/mcp:${DOCKER_TAG}"
    MCP_LATEST="${IMAGE_BASE}/mcp:latest"

    run docker build -t "$MCP_IMAGE" -t "$MCP_LATEST" -f "$MCP_DIR/Dockerfile" "$MCP_DIR"

    echo ""
fi

#──────────────────────────────────────────────────────────────────────
# 4. Commit, tag, and push
#──────────────────────────────────────────────────────────────────────
echo "==> Committing and tagging $GIT_TAG"

if [[ "$INCREMENT" == true ]]; then
    run git -C "$SCRIPT_DIR" add "$VERSION_FILE"
    run git -C "$SCRIPT_DIR" commit -m "Bump engine version to $VERSION"
fi

run git -C "$SCRIPT_DIR" tag -a "$GIT_TAG" -m "Release $GIT_TAG"
run git -C "$SCRIPT_DIR" push origin HEAD
run git -C "$SCRIPT_DIR" push origin "$GIT_TAG"

echo ""

#──────────────────────────────────────────────────────────────────────
# 5. Create release
#──────────────────────────────────────────────────────────────────────
echo "==> Creating release via $FORGE"

RELEASE_TITLE="Engine $GIT_TAG"
RELEASE_NOTES="## Docker images

\`\`\`bash
# NVIDIA GPU
docker pull ${NVIDIA_IMAGE}

# CPU only
docker pull ${CPU_IMAGE}
\`\`\`

## MCP server

\`\`\`bash
docker pull ${MCP_IMAGE:-${IMAGE_BASE}/mcp:${DOCKER_TAG}}
\`\`\`"

if [[ "$FORGE" == "gh" ]]; then
    run gh release create "$GIT_TAG" \
        --title "$RELEASE_TITLE" \
        --notes "$RELEASE_NOTES"

elif [[ "$FORGE" == "tea" ]]; then
    run tea release create \
        --tag "$GIT_TAG" \
        --title "$RELEASE_TITLE" \
        --note "$RELEASE_NOTES"
fi

echo ""

#──────────────────────────────────────────────────────────────────────
# 6. Push Docker images to registry
#──────────────────────────────────────────────────────────────────────
echo "==> Pushing Docker images to $REGISTRY"

run docker push "$NVIDIA_IMAGE"
run docker push "$NVIDIA_LATEST"
run docker push "$CPU_IMAGE"
run docker push "$CPU_LATEST"

if [[ -n "${MCP_IMAGE:-}" ]]; then
    run docker push "$MCP_IMAGE"
    run docker push "$MCP_LATEST"
fi

echo ""
echo "==> Release $GIT_TAG complete!"
echo ""
echo "    Images:"
echo "      $NVIDIA_IMAGE"
echo "      $CPU_IMAGE"
if [[ -n "${MCP_IMAGE:-}" ]]; then
    echo "      $MCP_IMAGE"
fi