package app

import (
	"context"
	"database/sql"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"net/http"
	"os"
	"path/filepath"
	"strconv"
	"strings"
)

func (a *App) handleDeployWebhook(w http.ResponseWriter, r *http.Request) {
	if r.Method != http.MethodPost {
		http.Error(w, "method not allowed", http.StatusMethodNotAllowed)
		return
	}
	path := strings.TrimPrefix(r.URL.Path, "/api/webhooks/deploy/")
	parts := strings.Split(path, "/")
	if len(parts) != 2 || parts[0] == "" || parts[1] == "" {
		http.Error(w, "bad path", http.StatusBadRequest)
		return
	}
	projectID, err := strconv.ParseInt(parts[0], 10, 64)
	if err != nil {
		http.Error(w, "invalid project id", http.StatusBadRequest)
		return
	}
	p, err := a.getProjectForWebhook(r.Context(), projectID, parts[1])
	if err != nil {
		http.Error(w, "unauthorized", http.StatusUnauthorized)
		return
	}
	var payload struct {
		Ref string `json:"ref"`
	}
	if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
		http.Error(w, "invalid json", http.StatusBadRequest)
		return
	}
	if payload.Ref != "refs/heads/main" {
		writeJSON(w, http.StatusAccepted, map[string]string{"status": "ignored", "reason": "not main branch"})
		return
	}
	if err := a.deployProjectFromMain(r.Context(), p); err != nil {
		log.Printf("deploy failed project_id=%d err=%v", p.ID, err)
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	writeJSON(w, http.StatusOK, map[string]string{"status": "deployed"})
}

func (a *App) getProjectForWebhook(ctx context.Context, projectID int64, token string) (Project, error) {
	var p Project
	err := a.db.QueryRowContext(ctx, `SELECT p.id, p.user_id, p.name, p.slug, p.description, p.repo_url, p.service_name, p.route_host, p.target_port, p.workspace_id, w.name, w.unix_user, p.deploy_token, p.created_at
		FROM projects p JOIN workspaces w ON w.id=p.workspace_id WHERE p.id=$1 AND p.deploy_token=$2`, projectID, token).
		Scan(&p.ID, &p.UserID, &p.Name, &p.Slug, &p.Description, &p.RepoURL, &p.ServiceName, &p.RouteHost, &p.TargetPort, &p.WorkspaceID, &p.Workspace, &p.UnixUser, &p.DeployToken, &p.CreatedAt)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return Project{}, errors.New("project not found")
		}
		return Project{}, err
	}
	p.WebhookURL = a.deployWebhookURL(p.ID, p.DeployToken)
	return p, nil
}

func (a *App) deployProjectFromMain(_ context.Context, p Project) error {
	if p.RepoURL == "" {
		return errors.New("project has no repo_url to deploy from")
	}
	projectDir, err := a.projectDirFor(p)
	if err != nil {
		return err
	}
	repoDir := filepath.Join(projectDir, "repo")
	if _, err := os.Stat(repoDir); err != nil {
		return fmt.Errorf("repo checkout missing at %s (trigger deploy webhook/push first)", repoDir)
	}
	binDir := filepath.Join(projectDir, "bin")
	if err := os.MkdirAll(binDir, 0o755); err != nil {
		return err
	}
	if _, err := os.Stat(repoDir); os.IsNotExist(err) {
		if err := runCmd("git", "clone", "--branch", "main", "--single-branch", p.RepoURL, repoDir); err != nil {
			return err
		}
	} else {
		if err := runCmd("git", "-C", repoDir, "remote", "set-url", "origin", p.RepoURL); err != nil {
			return err
		}
		if err := runCmd("git", "-C", repoDir, "fetch", "origin", "main", "--prune"); err != nil {
			return err
		}
		if err := runCmd("git", "-C", repoDir, "reset", "--hard", "origin/main"); err != nil {
			return err
		}
	}
	if err := a.buildProjectBinary(p); err != nil {
		return err
	}
	return runSystemctlUser(p.UnixUser, "restart", p.ServiceName)
}

func (a *App) buildProjectBinary(p Project) error {
	projectDir, err := a.projectDirFor(p)
	if err != nil {
		return err
	}
	repoDir := filepath.Join(projectDir, "repo")
	binDir := filepath.Join(projectDir, "bin")
	if err := os.MkdirAll(binDir, 0o755); err != nil {
		return err
	}
	if err := ensureOwnedByUnixUser(binDir, p.UnixUser, 0o755); err != nil {
		return err
	}
	binaryPath := filepath.Join(binDir, "app")
	if err := runCmd("go", "-C", repoDir, "build", "-o", binaryPath, "."); err != nil {
		return fmt.Errorf("build failed: %w", err)
	}
	if err := ensureOwnedByUnixUser(binaryPath, p.UnixUser, 0o755); err != nil {
		return err
	}
	return nil
}