package bridge

import (
	"crypto/rand"
	"encoding/hex"
	"encoding/json"
	"fmt"
	"io"
	"log"
	"os"
	"os/exec"
	"path/filepath"
	"strings"
	"time"

	"archive/zip"
)

// SummarizeResult holds artifact summary data
type SummarizeResult struct {
	Files     []string  `json:"files"`
	Timestamp time.Time `json:"timestamp"`
}

// SummarizeConfig configures summarization behavior
type SummarizeConfig struct {
	ArtifactsDir string
	OutputFile   string
}

// ApplyPatch applies a patch file to a new branch
func ApplyPatch(op PatchOperation) error {
	if op.PatchFile == "" || op.BranchName == "" {
		return fmt.Errorf("both --patch and --branch are required")
	}

	// create new branch
	cmd := exec.Command("git", "checkout", "-b", op.BranchName)
	if out, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("git checkout failed: %s: %w", string(out), err)
	}

	// apply patch
	cmd = exec.Command("git", "apply", op.PatchFile)
	if out, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("git apply failed: %s: %w", string(out), err)
	}

	log.Printf("[CI-Agent-Bridge] Patch applied to branch: %s", op.BranchName)
	return nil
}

// RevertBranch deletes a branch (hard reset)
func RevertBranch(branch string) error {
	if branch == "" {
		return fmt.Errorf("--branch is required")
	}

	// switch to main first
	cmd := exec.Command("git", "checkout", "main")
	if out, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("git checkout main failed: %s: %w", string(out), err)
	}

	// delete branch
	cmd = exec.Command("git", "branch", "-D", branch)
	if out, err := cmd.CombinedOutput(); err != nil {
		return fmt.Errorf("git branch delete failed: %s: %w", string(out), err)
	}

	log.Printf("[CI-Agent-Bridge] Branch reverted: %s", branch)
	return nil
}

// RunPodmanCompose executes podman-compose up
func RunPodmanCompose() error {
	log.Println("[CI-Agent-Bridge] Starting podman-compose...")
	cmd := exec.Command("podman-compose", "up", "-d")
	cmd.Stdout = os.Stdout
	cmd.Stderr = os.Stderr
	return cmd.Run()
}

// ZipDir compresses a directory into a ZIP archive
func ZipDir(srcDir, destZip string) error {
	zipFile, err := os.Create(destZip)
	if err != nil {
		return err
	}
	defer zipFile.Close()

	archive := zip.NewWriter(zipFile)
	defer archive.Close()

	return filepath.Walk(srcDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}

		// skip directories
		if info.IsDir() {
			return nil
		}

		// create file in archive
		relPath, _ := filepath.Rel(srcDir, path)
		zipEntry, err := archive.Create(relPath)
		if err != nil {
			return err
		}

		// copy file data
		file, err := os.Open(path)
		if err != nil {
			return err
		}
		defer file.Close()

		_, err = io.Copy(zipEntry, file)
		return err
	})
}

// SummarizeArtifacts creates a JSON summary and ZIP of artifacts
func SummarizeArtifacts(cfg SummarizeConfig) error {
	var files []string
	err := filepath.Walk(cfg.ArtifactsDir, func(path string, info os.FileInfo, err error) error {
		if err != nil {
			return err
		}
		if !info.IsDir() {
			relPath, _ := filepath.Rel(cfg.ArtifactsDir, path)
			files = append(files, relPath)
		}
		return nil
	})
	if err != nil {
		return fmt.Errorf("failed to walk artifacts dir: %w", err)
	}

	result := SummarizeResult{
		Files:     files,
		Timestamp: time.Now(),
	}

	// write JSON summary
	data, _ := json.MarshalIndent(result, "", "  ")
	if err := os.WriteFile(cfg.OutputFile, data, 0644); err != nil {
		return fmt.Errorf("failed to write summary: %w", err)
	}

	// create ZIP of artifacts
	zipPath := strings.TrimSuffix(cfg.OutputFile, filepath.Ext(cfg.OutputFile)) + ".zip"
	if err := ZipDir(cfg.ArtifactsDir, zipPath); err != nil {
		return fmt.Errorf("failed to create zip: %w", err)
	}

	log.Printf("[CI-Agent-Bridge] Artifacts summarized to %s (%d files)", cfg.OutputFile, len(files))
	return nil
}

// PatchOperation holds patch application parameters
type PatchOperation struct {
	PatchFile  string
	BranchName string
}

// generateSecureBranchName creates a cryptographically secure random branch name
func generateSecureBranchName() (string, error) {
	bytes := make([]byte, 16)
	if _, err := rand.Read(bytes); err != nil {
		return "", err
	}
	return "ai/" + hex.EncodeToString(bytes), nil
}