package main

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
)

// Project is one compose project as docker knows it.
type Project struct {
	Name        string   `json:"name"`
	Status      string   `json:"status,omitempty"`
	WorkingDir  string   `json:"working_dir,omitempty"`
	ConfigFiles []string `json:"config_files"`
	Services    []string `json:"services"`
	Running     int      `json:"running"`
	Containers  int      `json:"containers"`
}

// ProjectsAnswer is what docker_compose_projects answers.
type ProjectsAnswer struct {
	Count    int       `json:"count"`
	Projects []Project `json:"projects"`
}

// composeFiles are the names compose looks for in a directory, in its order.
var composeFiles = []string{"compose.yaml", "compose.yml", "docker-compose.yaml", "docker-compose.yml"}

// statDir says whether a path is a directory. Tests replace it.
var statDir = func(p string) bool {
	info, err := os.Stat(p)
	return err == nil && info.IsDir()
}

// statFile says whether a path is a regular file. Tests replace it.
var statFile = func(p string) bool {
	info, err := os.Stat(p)
	return err == nil && info.Mode().IsRegular()
}

// docker runs one docker command and names a daemon the account cannot reach as such.
func docker(args ...string) (Result, error) {
	r, err := call(Cmd{Name: "docker", Args: args})
	if err != nil && strings.Contains(r.Stderr, "permission denied") && strings.Contains(r.Stderr, "docker.sock") {
		return r, fmt.Errorf("the account cannot reach the container runtime's socket (permission denied): it is not in the docker group, or has not logged in since it was added. The docker module owns the group's members")
	}
	if err != nil && strings.Contains(r.Stderr, "Cannot connect to the Docker daemon") {
		return r, fmt.Errorf("the container runtime is not running on this machine: %s", firstLine(r.Stderr))
	}
	return r, err
}

// Projects merges what compose lists with what the containers' labels say.
func Projects() (ProjectsAnswer, error) {
	r, err := docker("compose", "ls", "--all", "--format", "json")
	if err != nil {
		return ProjectsAnswer{}, err
	}
	var listed []struct {
		Name        string `json:"Name"`
		Status      string `json:"Status"`
		ConfigFiles string `json:"ConfigFiles"`
	}
	if s := strings.TrimSpace(r.Stdout); s != "" {
		if err := json.Unmarshal([]byte(s), &listed); err != nil {
			return ProjectsAnswer{}, fmt.Errorf("docker compose ls answered what is not JSON: %v", err)
		}
	}
	by := map[string]*Project{}
	get := func(name string) *Project {
		if by[name] == nil {
			by[name] = &Project{Name: name, ConfigFiles: []string{}, Services: []string{}}
		}
		return by[name]
	}
	for _, l := range listed {
		p := get(l.Name)
		p.Status = l.Status
		p.ConfigFiles = splitFiles(l.ConfigFiles)
	}
	r, err = docker("ps", "-a", "--filter", "label=com.docker.compose.project", "--format",
		`{{.Label "com.docker.compose.project"}}`+"\t"+`{{.Label "com.docker.compose.project.working_dir"}}`+"\t"+
			`{{.Label "com.docker.compose.project.config_files"}}`+"\t"+`{{.Label "com.docker.compose.service"}}`+"\t{{.State}}")
	if err != nil {
		return ProjectsAnswer{}, err
	}
	services := map[string]map[string]bool{}
	for _, l := range lines(r.Stdout) {
		f := strings.Split(l, "\t")
		if len(f) < 5 || f[0] == "" {
			continue
		}
		p := get(f[0])
		if p.WorkingDir == "" {
			p.WorkingDir = f[1]
		}
		if len(p.ConfigFiles) == 0 {
			p.ConfigFiles = splitFiles(f[2])
		}
		if services[f[0]] == nil {
			services[f[0]] = map[string]bool{}
		}
		if f[3] != "" {
			services[f[0]][f[3]] = true
		}
		p.Containers++
		if f[4] == "running" {
			p.Running++
		}
	}
	out := ProjectsAnswer{Projects: []Project{}}
	for name, p := range by {
		for s := range services[name] {
			p.Services = append(p.Services, s)
		}
		sort.Strings(p.Services)
		if p.WorkingDir == "" && len(p.ConfigFiles) > 0 {
			p.WorkingDir = filepath.Dir(p.ConfigFiles[0])
		}
		out.Projects = append(out.Projects, *p)
	}
	sort.Slice(out.Projects, func(i, k int) bool { return out.Projects[i].Name < out.Projects[k].Name })
	out.Count = len(out.Projects)
	return out, nil
}

func splitFiles(s string) []string {
	out := []string{}
	for _, f := range strings.Split(s, ",") {
		if f = strings.TrimSpace(f); f != "" {
			out = append(out, f)
		}
	}
	return out
}

// Target is the project a tool acts on, and how compose is told which it is.
type Target struct {
	Project string   `json:"project,omitempty"`
	Dir     string   `json:"dir,omitempty"`
	Files   []string `json:"files,omitempty"`
}

// args are compose's own options naming the target.
func (t Target) args() []string {
	out := []string{"compose"}
	if t.Dir != "" {
		out = append(out, "--project-directory", t.Dir)
	}
	for _, f := range t.Files {
		out = append(out, "-f", f)
	}
	if t.Project != "" {
		out = append(out, "-p", t.Project)
	}
	return out
}

var projectName = regexp.MustCompile(`^[a-z0-9][a-z0-9_-]*$`)

// targetOf reads dir or project. A directory docker already knows a project for is that project,
// with the files it was started from; otherwise it must hold a compose file. needFiles says the
// tool reads the files (config, up, pull), so a project known only by its containers is not enough.
func targetOf(args map[string]any, needFiles bool) (Target, error) {
	dir, err := optText(args, "dir", "")
	if err != nil {
		return Target{}, err
	}
	name, err := optText(args, "project", "")
	if err != nil {
		return Target{}, err
	}
	if dir == "" && name == "" {
		return Target{}, fmt.Errorf("give dir, the project's directory, or project, its name")
	}
	if dir != "" {
		if !filepath.IsAbs(dir) {
			return Target{}, fmt.Errorf("dir must be an absolute path, not %q", dir)
		}
		dir = filepath.Clean(dir)
		if !statDir(dir) {
			return Target{}, fmt.Errorf("%s is not a directory on this machine", dir)
		}
	}
	if name != "" && !projectName.MatchString(name) {
		return Target{}, fmt.Errorf("%q is not a compose project name", name)
	}
	known, err := Projects()
	if err != nil {
		return Target{}, err
	}
	for _, p := range known.Projects {
		if (dir != "" && p.WorkingDir == dir) || (dir == "" && p.Name == name) {
			if name != "" && p.Name != name {
				continue
			}
			t := Target{Project: p.Name, Dir: p.WorkingDir}
			present := len(p.ConfigFiles) > 0
			for _, f := range p.ConfigFiles {
				present = present && statFile(f)
			}
			if present {
				t.Files = p.ConfigFiles
			} else if needFiles && !hasComposeFile(t.Dir) {
				return Target{}, fmt.Errorf("project %s was started from %s, which is no longer there", p.Name, strings.Join(p.ConfigFiles, ", "))
			}
			return t, nil
		}
	}
	if dir == "" {
		return Target{}, fmt.Errorf("no compose project named %s is known to docker here: give dir, its directory", name)
	}
	if !hasComposeFile(dir) {
		return Target{}, fmt.Errorf("%s holds no compose file (%s)", dir, strings.Join(composeFiles, ", "))
	}
	return Target{Dir: dir, Project: name}, nil
}

func hasComposeFile(dir string) bool {
	for _, f := range composeFiles {
		if statFile(filepath.Join(dir, f)) {
			return true
		}
	}
	return false
}

// Container is one of a project's containers.
type Container struct {
	Name     string   `json:"name"`
	Service  string   `json:"service"`
	State    string   `json:"state"`
	Status   string   `json:"status"`
	Health   string   `json:"health,omitempty"`
	ExitCode int      `json:"exit_code"`
	Image    string   `json:"image"`
	Ports    []string `json:"ports"`
}

// PsAnswer is what docker_compose_ps answers.
type PsAnswer struct {
	Target     Target      `json:"target"`
	Containers []Container `json:"containers"`
}

// jsonObjects reads compose's JSON output, which is one array or one object per line by version.
func jsonObjects(s string, into any) error {
	s = strings.TrimSpace(s)
	if s == "" {
		s = "[]"
	}
	if !strings.HasPrefix(s, "[") {
		s = "[" + strings.Join(lines(s), ",") + "]"
	}
	return json.Unmarshal([]byte(s), into)
}

// Ps answers a project's containers.
func Ps(t Target) (PsAnswer, error) {
	r, err := docker(append(t.args(), "ps", "-a", "--format", "json")...)
	if err != nil {
		return PsAnswer{}, err
	}
	var raw []struct {
		Name       string `json:"Name"`
		Service    string `json:"Service"`
		State      string `json:"State"`
		Status     string `json:"Status"`
		Health     string `json:"Health"`
		ExitCode   int    `json:"ExitCode"`
		Image      string `json:"Image"`
		Publishers []struct {
			URL           string `json:"URL"`
			TargetPort    int    `json:"TargetPort"`
			PublishedPort int    `json:"PublishedPort"`
			Protocol      string `json:"Protocol"`
		} `json:"Publishers"`
	}
	if err := jsonObjects(r.Stdout, &raw); err != nil {
		return PsAnswer{}, fmt.Errorf("docker compose ps answered what is not JSON: %v", err)
	}
	out := PsAnswer{Target: t, Containers: []Container{}}
	for _, c := range raw {
		ports := []string{}
		for _, p := range c.Publishers {
			if p.PublishedPort == 0 {
				continue
			}
			ports = append(ports, fmt.Sprintf("%s:%d->%d/%s", p.URL, p.PublishedPort, p.TargetPort, p.Protocol))
		}
		out.Containers = append(out.Containers, Container{Name: c.Name, Service: c.Service, State: c.State, Status: c.Status,
			Health: c.Health, ExitCode: c.ExitCode, Image: c.Image, Ports: ports})
	}
	return out, nil
}

// LogsAnswer is what docker_compose_logs answers.
type LogsAnswer struct {
	Target    Target   `json:"target"`
	Lines     []string `json:"lines"`
	Truncated bool     `json:"truncated,omitempty"`
}

var since = regexp.MustCompile(`^[0-9A-Za-z:.+-]+$`)

// Logs answers a project's last lines.
func Logs(t Target, services []string, n int, from string) (LogsAnswer, error) {
	args := append(t.args(), "logs", "--no-color", "--timestamps", "--tail", fmt.Sprint(n))
	if from != "" {
		if !since.MatchString(from) {
			return LogsAnswer{}, fmt.Errorf("since %q is neither a duration nor a timestamp", from)
		}
		args = append(args, "--since", from)
	}
	for _, s := range services {
		if err := plainName("service", s); err != nil {
			return LogsAnswer{}, err
		}
	}
	r, err := docker(append(args, services...)...)
	if err != nil {
		return LogsAnswer{}, err
	}
	// compose writes the containers' output on its stdout, and its own complaints on stderr.
	return LogsAnswer{Target: t, Lines: lines(r.Stdout), Truncated: r.Truncated}, nil
}

// ConfigAnswer is what docker_compose_config answers.
type ConfigAnswer struct {
	Target   Target         `json:"target"`
	Services []string       `json:"services"`
	Redacted int            `json:"redacted"`
	Rendered map[string]any `json:"rendered"`
}

// secretish is a name whose value is not shown.
var secretish = regexp.MustCompile(`(?i)(pass|secret|token|key|credential|auth|private|cert|cookie|session|salt|dsn|api)`)

// redact replaces the values of secret-looking names in the maps compose renders.
func redact(v any, count *int) {
	switch x := v.(type) {
	case map[string]any:
		for k, child := range x {
			switch k {
			case "environment", "args", "labels", "build_args":
				if m, ok := child.(map[string]any); ok {
					for name, val := range m {
						if val != nil && secretish.MatchString(name) {
							m[name] = "[redacted]"
							*count++
						}
					}
					continue
				}
			case "content":
				// An inline config or secret: its content is the secret itself.
				if _, ok := child.(string); ok {
					x[k] = "[redacted]"
					*count++
					continue
				}
			}
			redact(child, count)
		}
	case []any:
		for _, child := range x {
			redact(child, count)
		}
	}
}

// Config answers the rendered configuration.
func Config(t Target) (ConfigAnswer, error) {
	r, err := docker(append(t.args(), "config", "--format", "json")...)
	if err != nil {
		return ConfigAnswer{}, err
	}
	var rendered map[string]any
	if err := json.Unmarshal([]byte(r.Stdout), &rendered); err != nil {
		return ConfigAnswer{}, fmt.Errorf("docker compose config answered what is not JSON: %v", err)
	}
	out := ConfigAnswer{Target: t, Services: []string{}, Rendered: rendered}
	if s, ok := rendered["services"].(map[string]any); ok {
		for name := range s {
			out.Services = append(out.Services, name)
		}
		sort.Strings(out.Services)
	}
	redact(rendered, &out.Redacted)
	return out, nil
}

// ActAnswer is what an act answers: the target and the job that carries it.
type ActAnswer struct {
	Act    string `json:"act"`
	Target Target `json:"target"`
	Job    Job    `json:"job"`
}

func act(name string, t Target, extra ...string) (ActAnswer, error) {
	j, err := actAsJob(Cmd{Name: "docker", Args: append(append(t.args(), name), extra...)})
	if err != nil {
		return ActAnswer{}, err
	}
	return ActAnswer{Act: name, Target: t, Job: j}, nil
}

func checkServices(services []string) error {
	for _, s := range services {
		if err := plainName("service", s); err != nil {
			return err
		}
	}
	return nil
}

// Up brings a project up, detached.
func Up(t Target, services []string, build bool, pull string) (ActAnswer, error) {
	if err := oneOf("pull", pull, "missing", "always", "never"); err != nil {
		return ActAnswer{}, err
	}
	if err := checkServices(services); err != nil {
		return ActAnswer{}, err
	}
	extra := []string{"--detach", "--pull", pull}
	if build {
		extra = append(extra, "--build")
	}
	return act("up", t, append(extra, services...)...)
}

// Down stops and removes a project's containers and networks, keeping its volumes.
func Down(t Target) (ActAnswer, error) {
	return act("down", t)
}

// Restart restarts a project's containers.
func Restart(t Target, services []string) (ActAnswer, error) {
	if err := checkServices(services); err != nil {
		return ActAnswer{}, err
	}
	return act("restart", t, services...)
}

// Pull pulls a project's images.
func Pull(t Target, services []string) (ActAnswer, error) {
	if err := checkServices(services); err != nil {
		return ActAnswer{}, err
	}
	return act("pull", t, services...)
}