// Copyright (c) 2025-2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

// Package version provides build version information and user agent generation
package version

import (
	"fmt"
	"runtime"
	"runtime/debug"
	"strings"
)

// BuildInfo contains version and build information
type BuildInfo struct {
	Version   string
	Commit    string
	BuildDate string
	GoVersion string
}

// GetBuildInfo returns the current build information
func GetBuildInfo() BuildInfo {
	info := BuildInfo{
		Version:   "dev",
		Commit:    "unknown",
		BuildDate: "unknown",
		GoVersion: runtime.Version(),
	}

	bi, ok := debug.ReadBuildInfo()
	if !ok {
		return info
	}

	// Get module version
	if bi.Main.Version != "" && bi.Main.Version != "(devel)" {
		info.Version = bi.Main.Version
	}

	// Extract VCS information from build settings
	for _, s := range bi.Settings {
		switch s.Key {
		case "vcs.revision":
			info.Commit = s.Value
			// Truncate commit hash to 7 characters for brevity
			if len(info.Commit) > 7 {
				info.Commit = info.Commit[:7]
			}
		case "vcs.time":
			info.BuildDate = s.Value
		case "vcs.modified":
			// If working tree is modified, append -dirty to commit
			if s.Value == "true" && info.Commit != "unknown" {
				info.Commit += "-dirty"
			}
		}
	}

	return info
}

// UserAgent returns a formatted user agent string for the given component
func UserAgent(component string) string {
	info := GetBuildInfo()

	if info.Version == "dev" && info.Commit == "unknown" {
		// Simple format for development builds without VCS info
		return fmt.Sprintf("Probo/dev (%s) Go/%s", component, info.GoVersion)
	}

	// Full format with all available information
	parts := []string{
		fmt.Sprintf("Probo/%s", info.Version),
	}

	// Add component and metadata
	metadata := []string{component}
	if info.Commit != "unknown" {
		metadata = append(metadata, fmt.Sprintf("commit=%s", info.Commit))
	}

	if info.BuildDate != "unknown" {
		metadata = append(metadata, fmt.Sprintf("built=%s", info.BuildDate))
	}

	parts = append(parts, fmt.Sprintf("(%s)", strings.Join(metadata, "; ")))
	parts = append(parts, fmt.Sprintf("Go/%s", info.GoVersion))

	return strings.Join(parts, " ")
}