package clicmd

import (
	"context"
	"flag"
	"fmt"
	"os"
	"strconv"
	"strings"

	"github.com/iceBear67/simplepages/internal/client"
	"github.com/iceBear67/simplepages/internal/cliutil"
)

// stringList is a flag that may be given more than once.
type stringList []string

func (s *stringList) String() string { return strings.Join(*s, ",") }

func (s *stringList) Set(v string) error {
	*s = append(*s, v)
	return nil
}

func deployCmd(g *Globals) *cliutil.Command {
	var (
		activate    = true
		meta        stringList
		include     stringList
		exclude     stringList
		concurrency int
		retries     int
		follow      bool
		dryRun      bool
	)
	return &cliutil.Command{
		Name:  "deploy",
		Args:  "<dir>",
		Short: "Upload a directory and switch the site to it",
		Long: "Hashes the directory, uploads only the files the server does not\n" +
			"already have, then switches the project over in one step — a visitor\n" +
			"sees the old site or the new one, never a mixture.\n\n" +
			"Interrupting a deploy is safe: the blobs that made it are kept, so\n" +
			"running the same command again uploads only what is still missing.\n\n" +
			"Commit metadata is read from the CI environment (GitHub Actions,\n" +
			"GitLab CI) and can be set or overridden with --meta.",
		Flags: func(fs *flag.FlagSet) {
			fs.BoolVar(&activate, "activate", true, "switch the project to this deployment once it is uploaded")
			fs.Var(&meta, "meta", "`key=value` recorded with the deployment; repeatable")
			fs.Var(&include, "include", "only upload files matching `glob`; repeatable")
			fs.Var(&exclude, "exclude", "skip files and directories matching `glob`; repeatable")
			fs.IntVar(&concurrency, "concurrency", 8, "`number` of blobs uploaded at once")
			fs.IntVar(&retries, "retries", 4, "`number` of extra attempts per blob on a transient failure")
			fs.BoolVar(&follow, "follow-symlinks", false, "upload what symlinks point at instead of refusing them")
			fs.BoolVar(&dryRun, "dry-run", false, "scan and report without contacting the server")
		},
		Exec: func(ctx context.Context, args []string) error {
			if err := exactArgs(args, 1, "one directory"); err != nil {
				return err
			}
			dir := args[0]

			metaMap, err := parseMeta(meta)
			if err != nil {
				return err
			}

			p, err := g.Printer()
			if err != nil {
				return err
			}

			src, err := client.Scan(ctx, dir, client.ScanOptions{
				Include:        include,
				Exclude:        exclude,
				FollowSymlinks: follow,
			})
			if err != nil {
				return err
			}
			defer src.Close()

			if dryRun {
				// Deliberately offline: negotiating the manifest to find out what is
				// missing would create a deployment on the server, which is exactly
				// what --dry-run promises not to do.
				return p.Print(dryRunResult{
					Dir:         src.Dir,
					FileCount:   len(src.Files),
					TotalBytes:  src.TotalBytes,
					UniqueBlobs: src.UniqueBlobs(),
					Files:       src.Files,
				}, func() *cliutil.Table {
					t := cliutil.NewTable("PATH", "SIZE", "DIGEST")
					for _, f := range src.Files {
						t.Row(f.Path, cliutil.Bytes(f.Size), f.Digest[:12])
					}
					t.Row("", "", "")
					t.Row(fmt.Sprintf("%d files", len(src.Files)),
						cliutil.Bytes(src.TotalBytes),
						fmt.Sprintf("%d unique", src.UniqueBlobs()))
					return t
				})
			}

			project, err := g.ProjectName()
			if err != nil {
				return err
			}
			c, err := g.Client()
			if err != nil {
				return err
			}

			res, err := c.Deploy(ctx, client.DeployOptions{
				Project:     project,
				Source:      src,
				Meta:        metaMap,
				Activate:    activate,
				Concurrency: concurrency,
				Retries:     retries,
				// Progress goes to stderr so it stays out of a piped -o json
				// document, and is shown even without --verbose: the deduplication
				// win is the reason this tool exists, and a CI log should record it.
				Progress: func(msg string) { fmt.Fprintln(g.Err, msg) },
			})
			if err != nil {
				return err
			}

			return p.Print(res, func() *cliutil.Table {
				t := cliutil.NewTable()
				t.Row("deployment", res.Deployment.ID)
				t.Row("project", project)
				t.Row("state", res.Deployment.State)
				t.Row("files", strconv.Itoa(res.FileCount))
				t.Row("total_bytes", cliutil.Bytes(res.TotalBytes))
				t.Row("uploaded", fmt.Sprintf("%s, %s",
					cliutil.Plural(res.Uploaded, "blob"), cliutil.Bytes(res.UploadedBytes)))
				t.Row("reused", strconv.Itoa(res.Deduplicated))
				t.Row("activated", cliutil.Bool(res.Activated))
				t.Row("url", cliutil.Str(res.URL))
				return t
			})
		},
	}
}

// dryRunResult is what --dry-run reports: everything decided locally, and
// nothing that would need the server.
type dryRunResult struct {
	Dir         string             `json:"dir"`
	FileCount   int                `json:"file_count"`
	TotalBytes  int64              `json:"total_bytes"`
	UniqueBlobs int                `json:"unique_blobs"`
	Files       []client.LocalFile `json:"files"`
}

// parseMeta folds --meta over whatever the CI environment reveals, so an
// explicit flag always wins over a guessed value.
func parseMeta(pairs []string) (map[string]string, error) {
	out := detectCIMeta()
	for _, p := range pairs {
		k, v, ok := strings.Cut(p, "=")
		if !ok {
			return nil, cliutil.UsageErrorf("--meta %q: expected key=value", p)
		}
		k = strings.TrimSpace(k)
		if k == "" {
			return nil, cliutil.UsageErrorf("--meta %q: empty key", p)
		}
		if out == nil {
			out = make(map[string]string, len(pairs))
		}
		out[k] = v
	}
	return out, nil
}

// detectCIMeta reads the commit metadata the common CI systems export, so a
// deployment can be traced back to what produced it without every pipeline
// having to spell out the same four --meta flags.
func detectCIMeta() map[string]string {
	out := make(map[string]string, 4)
	set := func(key string, envs ...string) {
		for _, e := range envs {
			if v := strings.TrimSpace(os.Getenv(e)); v != "" {
				out[key] = v
				return
			}
		}
	}
	set("git_sha", "GITHUB_SHA", "CI_COMMIT_SHA", "GIT_COMMIT")
	set("git_ref", "GITHUB_REF_NAME", "CI_COMMIT_REF_NAME", "GIT_BRANCH")
	set("ci_run", "GITHUB_RUN_ID", "CI_PIPELINE_ID", "BUILD_NUMBER")
	set("actor", "GITHUB_ACTOR", "GITLAB_USER_LOGIN")

	if url := ciRunURL(); url != "" {
		out["ci_url"] = url
	}
	if len(out) == 0 {
		return nil
	}
	return out
}

// ciRunURL reconstructs a link back to the job. GitHub does not export one
// directly; GitLab does.
func ciRunURL() string {
	if v := strings.TrimSpace(os.Getenv("CI_PIPELINE_URL")); v != "" {
		return v
	}
	server := strings.TrimRight(os.Getenv("GITHUB_SERVER_URL"), "/")
	repo := os.Getenv("GITHUB_REPOSITORY")
	run := os.Getenv("GITHUB_RUN_ID")
	if server != "" && repo != "" && run != "" {
		return server + "/" + repo + "/actions/runs/" + run
	}
	return ""
}